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Novel mutations of OGG1 base excision repair pathway gene in laryngeal cancer patients
Abstract and Figures
OGG1 (The human 8-oxoguanine glycosylase 1) is the primary enzyme in BER (base excision repair) pathway, responsible for the excision of 7, 8-dihydro-8-oxoguanine (8-oxoG), a mutagenic base byproduct that occurs as a result of exposure to reactive oxygen species. OGG1 gene is highly polymorphic among humans and is mutated in cancer cells. In this case control study, all exons of OGG1 gene and its exon/intron boundaries were amplified in 210 laryngeal cancer cases and 210 matched controls and then analyzed by single stranded conformational polymorphism. Amplified products showing altered mobility patterns were sequenced and analyzed. Two silent (Gln718Gln, His699-700His) and three missense (Ala597, Thr608-610Pro and Glu707Lys) mutations were observed in exon 2. In addition to this one missense mutation (1578G > A) was also observed in 3'UTR region. We found a significant association between OGG1 mutations and laryngeal cancer and observed that His699-His700, silent mutation exhibited an enhanced risk of ~9.0 folds (OR = 9.07, 95 % CI = 4.73-17.39) and 1578G > A, missense mutation ~0.4 folds (OR = 0.37, 95 % CI = 0.15-0.90). Furthermore, a positive association of OGG1 mutations with smoking was observed in laryngeal cancer cases when compared to controls. Heavy smokers have higher incidence of OGG1 mutations when compared to light smokers in present study. Our results demonstrate that OGG1 mutations are associated with an increased risk of laryngeal cancer. OGG1 mutations were found to accumulate more of 8-OHdG in smokers, which may serve as a biomarker for early diagnosis of laryngeal cancer.
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... Almost 99% of de novo germline mutations in the Ogg1/Mutyh/Mth1 triple KO mice are C>A transversions, demonstrating the clear role of 8-oxoG repair in preventing C>A mutation. Additionally, missense mutations and loss-of-heterozygosity in Ogg1 have been associated with increased risk of human cancer (Mahjabeen et al., 2012;Chevillard et al., 1998), and copy-number losses of either Ogg1 or Mutyh are linked to elevated rates of spontaneous C>A mutation in human neuroblastoma (van den Boogaard et al., 2021). ...
Maintaining germline genome integrity is essential and enormously complex. Although many proteins are involved in DNA replication, proofreading, and repair, mutator alleles have largely eluded detection in mammals. DNA replication and repair proteins often recognize sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations – the frequencies of C>T, A>G, etc. – will differ between genomes that harbor either a mutator or wild-type allele. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs (Sasani et al., 2022, Ashbrook et al., 2021). In this study we developed a new method to detect alleles associated with mutation spectrum variation and applied it to mutation data from the BXDs. We discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1 , a DNA glycosylase involved in the same base-excision repair network as Mutyh (David et al., 2007). Its effect depends on the presence of a mutator allele near Mutyh , and BXDs with mutator alleles at both loci have greater numbers of C>A mutations than those with mutator alleles at either locus alone. Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles and may be applicable to mutation data from humans and other model organisms.
... Base excision repair is the main pathway for repair of oxidative base lesions in DNA (11) . OGG1 encodes the 8-Oxoguanine glycosylase 1 enzyme which is the primary enzyme which is BER (base excision repair pathway) (7,12) responsible for the excision of 7,8 dihydro-8oxoguanine (8-OxoG) a mutagenic base byproduct and other oxidatively damaged nucleobases from the DNA (7, 8) that occur as a result of exposure to reactive oxygen species (7) . OGG1 expression is increased upon inhalation or instillation of diesel exhausted particles indicating that base excision repair is activated (8) . ...
Objective: The aim of this study is to detect the effect of continuous exposure to Sodium Nitrite on 8-oxoguanineDNA glycosylase (OGG1) gene which responsible on DNA repairs. DNA repair play a major role in maintaininggenomic stability when DNA exposure to damage. Genomic stability is very important for keeping body cellshealthy and to prevent many types of tumor development. Many genes are responsible for this job; one of them isOGG1 gene.Methodology: In current study two groups of mice were chronically exposed to sodium nitrite for six months andeighteen months while third group was used as a control. Then sizes of OGG1 were estimated.Results: The results exhibited in the unexposed (control) mice had two different alleles for this gene while theexposed animals showed more polymorphisms and this finding is independent to the period of exposure.Conclusion obtained from this study indicated that sodium nitrite has ability to act on this gene that leads todevelop more polymorphisms.Recommendations: Other research should be done in order to detect how nitrite can act on this gene
... About 300-500 μl of blood was taken in 1.5 ml eppendorf tube, and genomic DNA was extracted from the blood using phenol chloroform extraction procedure as described by Mahjabeen et al. (2012). The resultant DNA isolated from this method was stored at − 20°C. ...
Ubiquitin-proteasome system (UPS) gene, PSMD1, is an important gene for neutralization of damaged and misfolded protein(s). The current study was designed to study the genetic and expression variations of PSMD1 gene as a consequence of arsenic exposure and its potential implications in arsenic induced diseases. In the present study, 250 blood samples of exposed industrial workers along with 250 controls were used. Initially, tetra amplification refractory mutation system-PCR was used to determine the role of PSMD1 gene polymorphisms (rs1549339, rs13402242) in industrial workers and controls. Frequency of homozygous mutant genotype of rs1549339 (OR: 2.23, 95% CI: 1.51-3.32, p = 0.0001) and rs13402242 (OR: 2.96, 95% CI: 1.52-5.75, p = 0.001) was observed significantly higher in exposed individuals vs controls. Secondly, qPCR was performed for expression analysis of PSMD1 gene. Significant down-regulated expression of PSMD1 gene (p < 0.0001) was observed vs controls, and this down-regulation was observed more pronounced in smokers (p < 0.0001) with maximum exposure duration (p < 0.0008). This down-regulated expression was observed significantly more pronounced in welding (p < 0.004) and brick kiln industries (p < 0.04) compared to other selected industries. The obtained results suggest that the exposure to arsenic may have an increased risk of developing disease(s) because of arsenic-induced PSMD1 variations.
... The obtained data on gene environment interactions illustrated a positive association between smoking and LSCC for OGG1 mutated patients: His699-700His, in case of light smokers, and Gln718Gln, Ala597Val, Glu707Lys, and His699-700His, in case of heavy smokers. In conclusion, both silent and missense mutations were found to accumulate in smokers and, particularly, His699-His700 silent mutation displayed an enhanced risk bỹ 9.0 fold to develop LSCC, thus suggesting a role in the risk prediction [63]. PIK3CA, FGFR3, JAK3, MET, and FBXW7. ...
Simple Summary
Laryngeal cancer represents one of the most common head and neck cancers worldwide. It can arise in different larynx subsites, each associated with specific clinical-pathological characteristics and treatment options. Due to the nonspecific symptoms, laryngeal cancer diagnosis often occurs in a late phase, resulting in delayed treatment and worse prognosis. Therefore, successful clinical management is strictly linked to the identification of reliable diagnostic and prognostic biomarkers. Herein, we provide an overview of the most promising molecular factors to date identified for both detection and monitoring, focusing on mutated genes, non-coding RNAs, transforming epigenetic events, inflammatory mediators, and immune-related agents.
Abstract
Laryngeal squamous cell cancer (LSCC) accounts for almost 25–30% of all head and neck squamous cell cancers and is clustered according to the affected districts, as this determines distinct tendency to recur and metastasize. A major role for numerous genetic alterations in driving the onset and progression of this neoplasm is emerging. However, major efforts are still required for the identification of molecular markers useful for both early diagnosis and prognostic definition of LSCC that is still characterized by significant morbidity and mortality. Non-coding RNAs appear the most promising as they circulate in all the biological fluids allowing liquid biopsy determination, as well as due to their quick and characteristic modulation useful for non-invasive detection and monitoring of cancer. Other critical aspects are related to recent progress in circulating tumor cells and DNA detection, in metastatic status and chemo-refractoriness prediction, and in the functional interaction of LSCC with chronic inflammation and innate immunity. We review all these aspects taking into account the progress of the technologies in the field of next generation sequencing.
... Mahjabeen et al. sequenced exons of XRCC1 in HNSCC and matched controls and found two missense mutations in 55% of cases and two silent mutations in 45% cases, accounting for a mutation frequency of 87% (16). Sequencing of RAD51C revealed five distinct heterozygous alterations in 5.8% of HNSCCs (17). ...
Head and neck squamous cell carcinomas (HNSCC) arising from the oral cavity, pharynx, and larynx constitute the 6th most common human cancer. Human papillomavirus (HPV)-positive tumours are distinct from HPV-negative counterparts, with HPV status affording clear clinical utility, prognostic benefit and better treatment outcomes. In contrast to their HPV-positive counterparts, HPV-negative tumours are characterized by high mutational load and chromosomal aberrations, with varying copy number alteration (CNA) profiles. HNSCC are distinct tumours at the chromosomal, gene and expression levels, with additional insight gained from immune profiling. Based on mutational analyses, HNSCC are categorized as HPV-positive, HPV-negative CNA-silent, and HPV-negative CNA-high tumours. Furthermore, gene expression profiling segregates these tumours into atypical, classical, basal, and mesenchymal, with clear differences observed between tumours of the oral cavity, oropharynx, hypopharynx and larynx. Additional immune profiling further classifies tumours as either immune-active or immune-exhausted. The clinical utility and impact of these tumour molecular subtypes however remains to be determined. HNSCC harbor high levels of somatic mutations. They display loss at 3p and 18q and gain at 3q and 8q, with mutations in CDKN2A, TP53, CCND1, EGFR, PIK3CA, PTEN, NOTCH1, NSD1, FAT1, AJUBA and KMT2D. Important pathways include the p53 and RB pathways which are involved in cell cycle control and are frequently lost in HPV-negative tumours, the WNT-β-catenin pathway related to the mesenchymal subtype and smoking etiology, and the PI3K pathway which includes the most common genetic alteration in HPV-positive HNSCC. Understanding the mutational, genomic and transcriptomic landscape of HNSCC has leveraged better therapeutic approaches to manage this group of diseases, and it is hoped that additional insight into the molecular subtypes of HNSCC and its specific subsites will further drive improved strategies to stratify and treat patients with this debilitating disease.
... About 300-500 μl of blood was taken in 1.5 ml eppendorf tube, and genomic DNA was extracted from the blood using phenol chloroform extraction procedure as described by Mahjabeen et al. (2012). The resultant DNA isolated from this method was stored at − 20°C. ...
Ubiquitin-proteasome system (UPS) gene, PSMD1, is an important gene for neutralization of damaged and misfolded protein(s). The current study was designed to study the genetic and expression variations of PSMD1 gene as a consequence of arsenic exposure and its potential implications in arsenic induced diseases. In the present study, 250 blood samples of exposed industrial workers along with 250 controls were used. Initially, tetra amplification refractory mutation system-PCR was used to determine the role of PSMD1 gene polymorphisms (rs1549339, rs13402242) in industrial workers and controls. Frequency of homozygous mutant genotype of rs1549339 (OR: 2.23, 95% CI: 1.51–3.32, p = 0.0001) and rs13402242 (OR: 2.96, 95% CI: 1.52–5.75, p = 0.001) was observed significantly higher in exposed individuals vs controls. Secondly, qPCR was performed for expression analysis of PSMD1 gene. Significant down-regulated expression of PSMD1 gene (p < 0.0001) was observed vs controls, and this down-regulation was observed more pronounced in smokers (p < 0.0001) with maximum exposure duration (p < 0.0008). This down-regulated expression was observed significantly more pronounced in welding (p < 0.004) and brick kiln industries (p < 0.04) compared to other selected industries. The obtained results suggest that the exposure to arsenic may have an increased risk of developing disease(s) because of arsenic-induced PSMD1 variations.
Maintaining germline genome integrity is essential and enormously complex. Hundreds of proteins are involved in DNA replication and proofreading, and hundreds more are mobilized to repair DNA damage [1]. While loss-of-function mutations in any of the genes encoding these proteins might lead to elevated mutation rates, mutator alleles have largely eluded detection in mammals.
DNA replication and repair proteins often recognize particular sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations — that is, the frequency of each individual mutation type (C>T, A>G, etc.) — will differ between genomes that harbor either a mutator or wild-type allele at a given locus. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs [2, 3].
In this study we developed a new method, called “inter-haplotype distance,” to detect alleles associated with mutation spectrum variation. By applying this approach to mutation data from the BXDs, we confirmed the presence of the germline mutator locus near Mutyh and discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1 and Mbd4, two DNA glycosylases involved in base-excision repair [4, 5]. The effect of a chromosome 6 mutator allele depended on the presence of a mutator allele near Mutyh, and BXDs with mutator alleles at both loci had even greater numbers of C>A mutations than those with mutator alleles at either locus alone.
Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles, and may be applicable to mutation data from humans and other model organisms.
Maintaining germline genome integrity is essential and enormously complex. Hundreds of proteins are involved in DNA replication and proofreading, and hundreds more are mobilized to repair DNA damage [1]. While loss-of-function mutations in any of the genes encoding these proteins might lead to elevated mutation rates, mutator alleles have largely eluded detection in mammals.
DNA replication and repair proteins often recognize particular sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations — that is, the frequency of each individual mutation type (C>T, A>G, etc.) — will differ between genomes that harbor either a mutator or wild-type allele at a given locus. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs [2, 3].
In this study we developed a new method, called “inter-haplotype distance,” to detect alleles associated with mutation spectrum variation. By applying this approach to mutation data from the BXDs, we confirmed the presence of the germline mutator locus near Mutyh and discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1 and Mbd4, two DNA glycosylases involved in base-excision repair [4, 5]. The effect of a chromosome 6 mutator allele depended on the presence of a mutator allele near Mutyh, and BXDs with mutator alleles at both loci had even greater numbers of C>A mutations than those with mutator alleles at either locus alone.
Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles, and may be applicable to mutation data from humans and other model organisms.
Today, treatment options for cancer patients typically include surgery, radiation therapy, immunotherapy, and chemotherapy. While these therapies have saved lives and reduced pain and suffering, cancer still takes millions of lives every year around the world. Researchers are now developing advanced therapeutic strategies such as immunotherapy, targeted therapy, and combination nanotechnology for drug delivery. In addition, the identification of new biomarkers will potentiate early-stage diagnosis. Molecular Targets and Cancer presents information about cancer diagnosis and therapy in a simple way. It covers several aspects of the topic with updated information on par with medical board levels. The book features contributions from experts and includes an overview of cancer from basic biology and pathology, classifications, surveillance, prevention, diagnosis, types of cancer, treatment and prognosis. The first part of this book introduces the reader to cancer epidemiology, genetic alterations in cancer, exogenous and endogenous factors in carcinogenesis, roles for growth factors in cancer progression, cell signaling in cancer, transcription factors in cancer, and cancer genetics and epigenetics. This comprehensive guide is a valuable resource for oncologists, researchers, and all medical professionals who work in cancer care and research.
Head and neck cancers are a heterogeneous group of neoplasms, affecting an ever increasing global population. Despite advances in diagnostic technology and surgical approaches to manage these conditions, survival rates have only marginally improved and this has occurred mainly in developed countries. Some improvements in survival, however, have been a result of new management and treatment approaches made possible because of our ever-increasing understanding of the molecular pathways triggered in head and neck oncogenesis, and the growing understanding of the abundant heterogeneity of this group of cancers. Some important pathways are common to other solid tumours, but their impact on reducing the burden of head and neck disease has been less than impressive. Other less known and little-explored pathways may hold the key to the development of potential druggable targets. The extensive work carried out over the last decade, mostly utilising next generation sequencing has opened up the development of many novel approaches to head and neck cancer treatment. This paper explores our current understanding of the molecular pathways of this group of tumours and outlines associated druggable targets which are deployed as therapeutic approaches in head and neck oncology with the ultimate aim of improving patient outcomes and controlling the personal and economic burden of head and neck cancer.
Many chemoradiation therapies cause DNA damage through oxidative stress. An important cellular mechanism that protects cells against oxidative stress involves DNA repair. One of the primary DNA repair mechanisms for oxidative DNA damage is base excision repair (BER). BER involves the tightly coordinated function of four enzymes (glycosylase, apurinic/apyrimidinic endonuclease, polymerase and ligase), in which 8-oxoguanine DNA glycosylase 1 initiates the cycle. An imbalance in the production of any one of these enzymes may result in the generation of more DNA damage and increased cell killing. In this study, we targeted mitochondrial DNA to enhance cancer chemotherapy by over-expressing a human 8-oxoguanine DNA glycosylase 1 (hOGG1) gene in the mitochondria of human hepatoma cells. Increased hOGG1 transgene expression was achieved at RNA, protein and enzyme activity levels. In parallel, we observed enhanced mitochondrial DNA damage, increased mitochondrial respiration rate, increased membrane potential and elevated free radical production. A greater proportion of the hOGG1-over-expressing hepatoma cells experienced apoptosis. Following exposure to a commonly used chemotherapeutic agent, cisplatin, cancer cells over-expressing hOGG1 displayed much shortened long-term survival when compared with control cells. Our results suggest that over-expression of hOGG1 in mitochondria may promote mitochondrial DNA damage by creating an imbalance in the BER pathway and sensitize cancer cells to cisplatin. These findings support further evaluation of hOGG1 over-expression strategies for cancer therapy.
An immunoperoxidase method using a monoclonal antiserum that recognizes 8-hydroxydeoxyguanosine has been developed for detection and quantitation of oxidative damage in single cells. The method was initially applied to cultured cells treated with H2O2 or aflatoxin B1 and then to cryostat liver sections of rats treated with aflatoxin B1. To demonstrate that the method has sufficient sensitivity for detection of damage in human samples, oral mucosal cells from a total of 12 pairs of smokers and nonsmokers were analyzed. Mean staining intensity of oral cells of smokers was 1.6-fold higher than in nonsmokers. The immunoperoxidase method, requiring a small number of cells and eliminating the need for isolation of DNA, will be useful for evaluation of oxidative damage in a wide range of biological samples.
To evaluate the effect of cigarette smoking on oxidative stress in lung tissues, we compared the levels of a type of oxidative DNA damage, 8-hydroxydeoxyguanosine (8-OH-dG), in tissue obtained from the central sites of lungs from 14 current smokers, seven ex-smokers and nine non-smokers. The mean level of 8-OH-dG in the lung tissues from smokers was 1.43-fold higher than that of the non-smokers (the difference was statistically significant, P = 0.0262). A positive correlation between the 8-OH-dG levels in normal lung tissues and the Brinkman index was obtained from smokers and ex-smokers (r = 0.525; P = 0.0134). A positive correlation was also obtained for the 8-OH-dG levels in normal lung tissues and the number of cigarettes smoked per day (r = 0.436; P = 0.0132). These results suggest that oxidative DNA damage is induced in lung DNA by cigarette smoking.
The human OGG1 gene encodes a DNA glycosylase activity catalysing the excision of the mutagenic lesion 7,8-dihydro-8-oxoguanine from oxidatively damaged DNA. The OGG1 gene was localized to chromosome 3p25, a region showing frequent loss of heterozygosity (LOH) in lung and kidney tumours. In this study, we have analysed by RT-PCR the expression of OGG1 in 25 small cell lung cancers, in 15 kidney carcinomas and the 15 normal kidney counterparts. The results show that OGG1 messenger RNA can be detected in all tumours tested and that no significant difference was observed in the level of expression between normal and tumoral kidney tissues. Denaturing gradient gel electrophoresis (DGGE) was used to screen this series of human tumours for alterations in the OGG1 cDNA. The study revealed homozygous mutations in three tumours, two from lung and one from kidney. Sequencing analysis of the mutants identified a single base substitution in each of the three cases: two transversions (GC to TA and TA to AT) and one transition (GC to AT). All three substitutions cause an amino acid change in the hOgg1 protein. For the mutant kidney tumour, the normal tissue counterpart shows a wild-type profile. These results suggest a role for OGG1 mutations in the course of the multistage process of carcinogenesis in lung or kidney.
Active oxygen species (AOS) such as O2- and H2O2 have been shown to be generated from both gas and tar phases of cigarette smoke and it has been suggested that they are involved in carcinogenesis due to cigarette smoking. Therefore, we investigated the effect of cigarette smoking on oxidative DNA damages in human peripheral blood cells using 8-hydroxydeoxy-guanosine (8-OH-dG) as a marker. From ten healthy male volunteers aged 20-22 years, 5 ml of blood was taken before and 10 minutes after smoking 2 cigarettes in 10 minutes. After lysis of blood cell membranes leukocyte DNA was isolated using a DNA extractor and 8-OH-dG levels were determined using high performance liquid chromatography (HPLC) with electrochemical detection. The mean levels of 8-OH-dG increased significantly (P less than 0.05) from 3.3 +/- 0.8/10(6) dG (mean +/- SD) to 5.1 +/- 2.5 after smoking. These results indicate that cigarette smoking induces oxidative DNA damage in peripheral blood cells in a relatively short time.
To investigate the oxidative stress induced by cigarette smoking, the levels of a form of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), and its repair activity in the leukocytes of current smokers, ex-smokers, and complete nonsmokers were measured. The mean level of 8-OH-Gua was 1.88-fold higher in smokers as compared to complete nonsmokers (the difference was statistically significant, P = 0.013). The mean 8-OH-Gua repair activity was 1.6-fold higher in smokers than complete nonsmokers (the difference was statistically significant, P = 0.0053). A positive association was observed for the 8-OH-Gua levels and its repair activity. Considerable interindividual variations in the 8-OH-Gua levels (current smokers, 3.5-fold; nonsmokers, 7.2-fold) and in its repair activity (current smokers, 7.5-fold; nonsmokers. 5.5-fold) were observed. These results demonstrate that not only smoking status but also life-style, environment, and genetic differences might have effects on the level of 8-OH-Gua and its repair activity in human leukocytes.
Base-excision DNA repair proteins that target alkylation damage act on a variety of seemingly dissimilar adducts, yet fail to recognize other closely related lesions. The 1.8 A crystal structure of the monofunctional DNA glycosylase AlkA (E. coli 3-methyladenine-DNA glycosylase II) reveals a large hydrophobic cleft unusually rich in aromatic residues. An Asp residue projecting into this cleft is essential for catalysis, and it governs binding specificity for mechanism-based inhibitors. We propose that AlkA recognizes electron-deficient methylated bases through pi-donor/acceptor interactions involving the electron-rich aromatic cleft. Remarkably, AlkA is similar in fold and active site location to the bifunctional glycosylase/lyase endonuclease III, suggesting the two may employ fundamentally related mechanisms for base excision.