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Primary tumours of bone present a significant diagnostic and therapeutic challenge at times. Silver stained nucleolar organiser regions (AgNORs) have been widely used in a variety of tissues but with a limited study on bone tumours. Our study was aimed at the evaluation of AgNOR count in various neoplastic lesions of bone.
: One hundred biopsies of...
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In carbon monoxide (CO) poisoning, CO affects the oxygen-carrying capacity of the hemoglobin molecule. Nucleolar-organizing regions (NORs) are genetic loci on chromosomes that are composed of ribosomal DNA and proteins. NORs can be stained with silver. A total of 18 rats were exposed to CO in three different concentrations (1000, 3000, and 5000 ppm...
SUMMARY nl ). The concentrations of reducible silver, developed silver, and silver nuclei in the sections were determined, but it is doubtful if the values obtained for silver nuclei are significant. All three forms of silver increased with pH, time, and the concentration of silver in the impregnating solution. Temperature of impregnation had littl...
An evaluation of the cellular alterations in the smoker's oral mucosal cells was performed. Exfoliative Citology technique were applied and the cytologic smears stained with silver for quantitative analyses of Argyrophilic nucleolar organizer regions. (AgNORs). Cytologic smears were collected from two anatomic sites, mouth floor and tongue border w...
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... But less studies finding a significant relationship between the decrease in the mAgNOR post-therapy with stage. (13,23,24) Chemoradiotherapy is a chemotherapy combined with radiotherapy concurrently used to control tumor lokoregional and improve the survival of patients in order to overcome cancer cells systemically through microcirculation. In this study most of the samples will undergo neoadjuvant chemotherapy intended to reduce the size of the tumor before radiotherapy. ...
BACKGROUND: Nasopharyngeal carcinoma (NPC) is malignant tumor growing in nasopharynx with a predilection in fossa Rossenmuller and nasopharyngeal roof. This research aimed to prove whether the means of argyrophilic nucleolar organizer region (mAgNOR) can predict the success of treatment in nasopharyngeal carcinoma patients.
METHODS: We used diagnostic test method with longitudinal design and purposive sampling technique. Endoscopic biopsy examination was performed on 15 nasopharyngeal carcinoma patients before and after therapy, 13 patients underwent chemotherapy and other two underwent chemoradiotherapy. Tumor tissues were stained and AgNOR was calculated.
RESULTS: Based on the tumor stage, sample characteristic showed 3 patients (20%) were in stage II, 3 patients (20%) in stage III, and 9 patients (60%) in stage IV, with pre- and post-therapy mAgNOR were 1.610±0.988 and 1.000±0.000, respectively in stage II, 1.100±0.092 and 1.000±0.000, respectively in stage III, 1.226±0.265 and 1.107±0.164, respectively in stage IV patients. Based on histopathology type, 4 patients (26.7%) had non keratinizing squamous cell carcinoma with pre- and post-therapy mAgNOR were 1.117±0.134 and 1.060±0.120, respectively, while 11 patients (73.3%) had undifferentiated squamous cell carcinoma with pre- and post-therapy mAgNOR were 1.335±0.528 and 1.065±0.146, respectively. Overall the pre-therapy were significantly higher than post-therapy mAgNOR. In subgroups there are significant differences in stage IV and type 3.
CONCLUSION: The values of AgNOR were decreased in all NPC stages and significantly decreased in undifferentiated squamous cell carcinoma. AgNOR can be used to predict the successfulness of therapy in NPC.
KEYWORDS: nasopharyngeal carcinoma, therapy, proliferation, mAgNOR
... In fact, there is more than one evidence that reports similar behavior between a cancer cell and a proliferating cell of a sea urchin embryo, since these two kinds of cells have both their metabolism oriented to support the accelerated ribosome biogenesis. Firstly it was reported that the cell of the bone cancer has an active nucleolar organizer (Arora et al., 2003), as well as the repression of rRNA synthesis in nucleolus and the parallel synthesis of p53 and p21 proteins determine the block of cell cycle and subsequently apoptosis of osteosarcoma cells (Montanaro et al., 2007). Moreover, was described that Myc oncogene plays a key role in elevating rDNA transcription, (reviewed in Woods et al., 2015; Kusnadi et al., 2015). ...
We previously reported the characterization 5S ribosomal DNA (rDNA) clusters in the common sea urchin Paracentrotus lividus and demonstrated the presence of DNA methylation-dependent silencing of embryo specific 5S rDNA cluster in adult tissue. In this work, we show genetic and epigenetic characterization of 18S-26S rDNA clusters in this specie. The results indicate the presence of three different 18S-26S rDNA clusters with different Non-Transcribed Spacer (NTS) regions that have different chromosomal localizations. Moreover, we show that the two largest clusters are hyper- methylated in the promotors-containing NTS regions in adult tissues, as in the 5S rDNA. These findings demonstrate an analogous epigenetic regulation in small and large rDNA clusters and support the logical synchronism in building ribosomes. In fact, all the ribosomal RNA genes must be synchronously and equally transcribed to perform their unique final product.
... In tumorigenesis and cancer progression, ribosome biogenesis is an important process, and cancer cells generally exhibit increased ribosome synthesis, leading to larger nucleoli than observed in normal cells, 3,4 a factor that is predictive of cancer aggressiveness, 5,6 Ribosome synthesis requires the coordinated actions of all three DNA-dependent RNA polymerases (Pol I, II, and III). 7,8 RNA polymerase 1 transcription termination factor (TTF1) participates in ribosome synthesis by mediating ribosomal RNA (rRNA) gene activation and silencing. ...
RNA polymerase 1 transcription termination factor (TTF1) mediates the transcription of ribosomal RNA (rRNA). In the current study, we investigated the clinical and biological significance of the TTF1 gene in colorectal cancer (CRC).
The expression of TTF1 messenger RNA (mRNA) in tumor and normal tissues from 136 patients with CRC was examined by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). We also performed in vitro cell proliferation and migration assays in TTF1-expressing CRC cells. The biological role of TTF1 in CRC was further elucidated using gene set enrichment analysis (GSEA) with CRC samples.
TTF1 expression was significantly higher in tumor tissues than in corresponding normal tissues (p = 0.016). In clinicopathological analysis, the high-TTF1 expression group showed a higher incidence of liver metastasis and lymphatic invasion than the low-TTF1 expression group (p < 0.05), and tended to have more frequent venous invasion than the low-TTF1 expression group. Furthermore, the high-TTF1 expression group had a significantly poorer prognosis than the low-TTF1 expression group (p = 0.011). Moreover, overexpression of TTF1 enhanced the proliferation and migration capacity of CRC cells in vitro. GSEA revealed that TTF1 was significantly associated with the RAS and MYC pathways, and this observation was confirmed in samples from 136 patients with CRC.
TTF1 was involved in cancer progression via the RAS and MYC pathways in CRC, suggesting that TTF1 may be a prognostic indicator and therapeutic target in CRC.
Precise regulation of ribosome biogenesis is fundamental to maintain normal cell growth and proliferation, and accelerated ribosome biogenesis is associated with malignant transformation. Here, we show that the kinase AKT regulates ribosome biogenesis at multiple levels to promote ribosomal RNA (rRNA) synthesis. Transcription elongation by RNA polymerase I, which synthesizes rRNA, required continuous AKT-dependent signaling, an effect independent of AKT's role in activating the translation-promoting complex mTORC1 (mammalian target of rapamycin complex 1). Sustained inhibition of AKT and mTORC1 cooperated to reduce rRNA synthesis and ribosome biogenesis by additionally limiting RNA polymerase I loading and pre-rRNA processing. In the absence of growth factors, constitutively active AKT increased synthesis of rRNA, ribosome biogenesis, and cell growth. Furthermore, AKT cooperated with the transcription factor c-MYC to synergistically activate rRNA synthesis and ribosome biogenesis, defining a network involving AKT, mTORC1, and c-MYC as a master controller of cell growth. Maximal activation of c-MYC-dependent rRNA synthesis in lymphoma cells required AKT activity. Moreover, inhibition of AKT-dependent rRNA transcription was associated with increased lymphoma cell death by apoptosis. These data indicate that decreased ribosome biogenesis is likely to be a fundamental component of the therapeutic response to AKT inhibitors in cancer.
