Ascorbate radiosensitizes pancreatic cancer cells 

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... our present study we have shown that pharmacological ascorbate significantly decreases clonogenic survival and inhibits the growth of all pancreatic cancer cell lines as a single agent, as well as sensitizes cancer cells to IR. This corresponds well with other reports demonstrating that pharmacological ascorbate enhances IR-induced cell killing and DNA fragmentation leading to induction of apoptosis in HL60 leukemia cells ( 39 ). In addition, Hurst et al. demonstrated that pharmacological ascorbate combined with IR leads to increased numbers of double-strand DNA breaks and cell cycle arrest when compared to either treatment alone ( 40 ). Our previous studies demonstrated that pharmacological ascorbate could serve as a "pro-drug" for the delivery of H 2 O 2 to tumors (1, 2, 3, 4). There was both a time and dose-dependent increase in measured H 2 O 2 production with increased concentrations of ascorbate. Others have demonstrated increased levels of double-strand breaks with pharmacological ascorbate and H 2 O 2 treatment to tumor cells ( 41,42 ). In addition, the double-strand breaks induced by H 2 O 2 were more slowly ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

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... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 17

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 18

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 19

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 20

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 21

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 22

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 23

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 24

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 25

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 26

... our present study we have shown that pharmacological ascorbate significantly decreases clonogenic survival and inhibits the growth of all pancreatic cancer cell lines as a single agent, as well as sensitizes cancer cells to IR. This corresponds well with other reports demonstrating that pharmacological ascorbate enhances IR-induced cell killing and DNA fragmentation leading to induction of apoptosis in HL60 leukemia cells ( 39 ). In addition, Hurst et al. demonstrated that pharmacological ascorbate combined with IR leads to increased numbers of double-strand DNA breaks and cell cycle arrest when compared to either treatment alone ( 40 ). Our previous studies demonstrated that pharmacological ascorbate could serve as a "pro-drug" for the delivery of H 2 O 2 to tumors (1, 2, 3, 4). There was both a time and dose-dependent increase in measured H 2 O 2 production with increased concentrations of ascorbate. Others have demonstrated increased levels of double-strand breaks with pharmacological ascorbate and H 2 O 2 treatment to tumor cells ( 41,42 ). In addition, the double-strand breaks induced by H 2 O 2 were more slowly ...

Context 27

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 28

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 29

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 30

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 31

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 32

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 33

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 34

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 35

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 36

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 37

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 38

... studies from our laboratory have demonstrated that pharmacological ascorbate is cytotoxic to pancreatic cancer cells while normal cells are resistant (1). To test the effect of ascorbate on radiation response in cancer vs. non-cancerous cell lines, we performed clonogenic ( Figure 1A -D) and cell viability assays ( Figure 1E, F) using three pancreatic ductal adenocarcinomas (MIA PaCa-2, PANC-1 ( Figure A, B) and AsPC-1 ( Figure 1C), compared to normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). The radiation survival curves were normalized to ascorbate-or sham-treated controls and fit with a linear quadratic model. Pharmacological ascorbate (0.25 mM) enhanced IR-induced decreases in clonogenic survival. The pancreatic cancer cell lines showed dose modification factors at 10% iso-survival of 2.5 (MIA PaCa-2) and 2.2 (PANC-1) ( Figure 1A, B) and 1.25 (AsPC-1, Figure 1C). In contrast no radio-sensitization was noted with ascorbate in the normal non-tumorigenic H6c7 pancreatic ductal epithelial cells ( Figure 1D). Similar results were seen using cell viability where there was radiosensitization in the MIA PaCa-2 cell line ( Figure 1E) but no radiosensitization in the H6c7 cell line ( Figure 1F). To determine if ascorbate radiosensitization occurs in the physiologically relevant environment seen in pancreatic cancer, we treated patient derived pancreatic cancer cell lines, 339 ( Figure 1G) and 403 ( Figure 1H) (13,14) in 4% O 2 . Again we demonstrated ascorbate radiosensitization in the 339 line with a DMF of 1.4 at 40% iso-survival and a DMF of 1.6 in the 403 cell line at 40% iso-survival. The timing for the administration of pharmacological ascorbate is also important. Treating cells with ascorbate for 1 h prior to IR or 1 h immediately after IR demonstrated a similar decrease in clonogenic survival when compared to IR or ascorbate alone. However, when ascorbate was administered 6 h after IR, the decrease in clonogenic survival was decreased (Supplemental Information Figure 1). These data strongly support the hypothesis that pharmacological ascorbate is a selective radio-sensitizer in pancreatic cancer cells vs. normal non-tumorigenic pancreatic ductal epithelial ...

Context 39

... our present study we have shown that pharmacological ascorbate significantly decreases clonogenic survival and inhibits the growth of all pancreatic cancer cell lines as a single agent, as well as sensitizes cancer cells to IR. This corresponds well with other reports demonstrating that pharmacological ascorbate enhances IR-induced cell killing and DNA fragmentation leading to induction of apoptosis in HL60 leukemia cells ( 39 ). In addition, Hurst et al. demonstrated that pharmacological ascorbate combined with IR leads to increased numbers of double-strand DNA breaks and cell cycle arrest when compared to either treatment alone ( 40 ). Our previous studies demonstrated that pharmacological ascorbate could serve as a "pro-drug" for the delivery of H 2 O 2 to tumors (1, 2, 3, 4). There was both a time and dose-dependent increase in measured H 2 O 2 production with increased concentrations of ascorbate. Others have demonstrated increased levels of double-strand breaks with pharmacological ascorbate and H 2 O 2 treatment to tumor cells ( 41,42 ). In addition, the double-strand breaks induced by H 2 O 2 were more slowly ...