scholarly journals Pan-cancer analysis of non-oncogene addiction to DNA repair

Author(s):  
Luis Bermúdez-Guzmán

Abstract Cancer cells usually depend on the aberrant function of one or few driver genes to initiate and promote their malignancy, an attribute known as oncogene addiction. However, cancer cells might become dependent on the normal cellular functions of certain genes that are not oncogenes but ensure cell survival (non-oncogene addiction). The downregulation of DNA repair genes and the consequent genetic and epigenetic instability is key to promote malignancy, but the activation of the DNA-damage response (DDR) has been shown to become a type of non-oncogene addiction that critically supports tumour survival. While we know that different cancer types can become dependent on specific DDR genes for their survival, a systematic evaluation of DNA repair addiction at the pan-cancer level is missing. In the present study, this systematic evaluation was addressed using data derived from The Cancer Dependency Map and The Cancer Genome Atlas (TCGA). Following this approach, 59 DDR genes were identified as commonly essential in cancer cells with 14 genes being exclusively associated with better overall patient survival and 19 with worse overall survival. Notably, a specific molecular signature among the latter, characterized by DDR genes showing the weakest dependency scores, but significant upregulation was strongly associated with worse survival, supporting the presence and relevance of non-oncogenic addiction to DNA repair in cancer. Particularly, UBE2T, RFC4, POLQ, BRIP1, and H2AFX represent the best predictors of poor overall survival, and some might represent promising therapeutic targets, especially under the synthetic lethality approach.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luis Bermúdez-Guzmán

AbstractCancer cells usually depend on the aberrant function of one or few driver genes to initiate and promote their malignancy, an attribute known as oncogene addiction. However, cancer cells might become dependent on the normal cellular functions of certain genes that are not oncogenes but ensure cell survival (non-oncogene addiction). The downregulation or silencing of DNA repair genes and the consequent genetic and epigenetic instability is key to promote malignancy, but the activation of the DNA-damage response (DDR) has been shown to become a type of non-oncogene addiction that critically supports tumour survival. In the present study, a systematic evaluation of DNA repair addiction at the pan-cancer level was performed using data derived from The Cancer Dependency Map and The Cancer Genome Atlas (TCGA). From 241 DDR genes, 59 were identified as commonly essential in cancer cell lines. However, large differences were observed in terms of dependency scores in 423 cell lines and transcriptomic alterations across 18 cancer types. Among these 59 commonly essential genes, 14 genes were exclusively associated with better overall patient survival and 19 with worse overall survival. Notably, a specific molecular signature among the latter, characterized by DDR genes like UBE2T, RFC4, POLQ, BRIP1, and H2AFX showing the weakest dependency scores, but significant upregulation was strongly associated with worse survival. The present study supports the existence and importance of non-oncogenic addiction to DNA repair in cancer and may facilitate the identification of prognostic biomarkers and therapeutic opportunities.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Daniel R. Principe ◽  
Matthew Narbutis ◽  
Regina Koch ◽  
Ajay Rana

AbstractPARP inhibitors have shown remarkable efficacy in the clinical management of several BRCA-mutated tumors. This approach is based on the long-standing hypothesis that PARP inhibition will impair the repair of single stranded breaks, causing synthetic lethality in tumors with loss of high-fidelity double-strand break homologous recombination. While this is now well accepted and has been the basis of several successful clinical trials, emerging evidence strongly suggests that mutation to several additional genes involved in homologous recombination may also have predictive value for PARP inhibitors. While this notion is supported by early clinical evidence, the mutation frequencies of these and other functionally related genes are largely unknown, particularly in cancers not classically associated with homologous recombination deficiency. We therefore evaluated the mutation status of 22 genes associated with the homologous recombination DNA repair pathway or PARP inhibitor sensitivity, first in a pan-cancer cohort of 55,586 patients, followed by a more focused analysis in The Cancer Genome Atlas cohort of 12,153 patients. In both groups we observed high rates of mutations in a variety of HR-associated genes largely unexplored in the setting of PARP inhibition, many of which were associated also with poor clinical outcomes. We then extended our study to determine which mutations have a known oncogenic role, as well as similar to known oncogenic mutations that may have a similar phenotype. Finally, we explored the individual cancer histologies in which these genomic alterations are most frequent. We concluded that the rates of deleterious mutations affecting genes associated with the homologous recombination pathway may be underrepresented in a wide range of human cancers, and several of these genes warrant further and more focused investigation, particularly in the setting of PARP inhibition and HR deficiency.


2021 ◽  
Vol 12 ◽  
Author(s):  
Zhenyu Xie ◽  
Xin Li ◽  
Yuzhen He ◽  
Song Wu ◽  
Shiyue Wang ◽  
...  

BackgroundTriggering receptor expressed on myeloid cells-1 (TREM-1) has been reported as a biomarker in many cancers. However, the biological function of TREM-1 in papillary thyroid carcinoma (PTC) remains unknown.MethodsWe obtained TREM-1 expression data from The Cancer Genome Atlas (TCGA) database. Enrichment analysis of coexpressed genes and TREM-1 methylation analysis were performed via LinkedOmics. The correlations between TREM-1 and immune infiltrates were investigated via ESTIMATE, TIMER and TISIDB. We analyzed the association of TREM-1 expression with pan-cancer overall survival via Gene Expression Profiling Interactive Analysis (GEPIA).ResultsTREM-1 has lower methylation levels and higher expression levels in PTC tissues compared to normal tissues. TREM-1 expression is significantly associated with poor prognosis, advanced T classification, advanced N classification, and an increased incidence of BRCA2 and BRAF mutations. Genes coexpressed with TREM-1 primarily participate in immune-related pathways. TREM-1 expression is positively correlated with immune infiltration, tumor progression and poor overall survival across cancers.ConclusionsTREM-1 is a good prognostic and diagnostic biomarker in PTC. TREM-1 may promote thyroid cancer progression through immune-related pathways. Methylation may act as an upstream regulator of TREM-1 expression and biological function. Additionally, TREM-1 has broad prognostic value in a pan-cancer cohort.


2019 ◽  
Vol 116 (35) ◽  
pp. 17438-17443 ◽  
Author(s):  
Gayathri Srinivasan ◽  
Elizabeth A. Williamson ◽  
Kimi Kong ◽  
Aruna S. Jaiswal ◽  
Guangcun Huang ◽  
...  

Defects in DNA repair give rise to genomic instability, leading to neoplasia. Cancer cells defective in one DNA repair pathway can become reliant on remaining repair pathways for survival and proliferation. This attribute of cancer cells can be exploited therapeutically, by inhibiting the remaining repair pathway, a process termed synthetic lethality. This process underlies the mechanism of the Poly-ADP ribose polymerase-1 (PARP1) inhibitors in clinical use, which target BRCA1 deficient cancers, which is indispensable for homologous recombination (HR) DNA repair. HR is the major repair pathway for stressed replication forks, but when BRCA1 is deficient, stressed forks are repaired by back-up pathways such as alternative nonhomologous end-joining (aNHEJ). Unlike HR, aNHEJ is nonconservative, and can mediate chromosomal translocations. In this study we have found that miR223-3p decreases expression of PARP1, CtIP, and Pso4, each of which are aNHEJ components. In most cells, high levels of microRNA (miR) 223–3p repress aNHEJ, decreasing the risk of chromosomal translocations. Deletion of the miR223 locus in mice increases PARP1 levels in hematopoietic cells and enhances their risk of unprovoked chromosomal translocations. We also discovered that cancer cells deficient in BRCA1 or its obligate partner BRCA1-Associated Protein-1 (BAP1) routinely repress miR223-3p to permit repair of stressed replication forks via aNHEJ. Reconstituting the expression of miR223-3p in BRCA1- and BAP1-deficient cancer cells results in reduced repair of stressed replication forks and synthetic lethality. Thus, miR223-3p is a negative regulator of the aNHEJ DNA repair and represents a therapeutic pathway for BRCA1- or BAP1-deficient cancers.


2020 ◽  
Author(s):  
Ran Wei ◽  
Jichuan Quan ◽  
Shuofeng Li ◽  
Zhao Lu ◽  
Xu Guan ◽  
...  

Abstract Background: Cancer stem cells (CSCs), which are characterized by self-renewal and plasticity, are highly correlated with tumor metastasis and drug resistance. To fully understand the role of CSCs in colorectal cancer (CRC), we evaluated the stemness traits and prognostic value of stemness-related genes in CRC.Methods: In this study, the data from 616 CRC patients from The Cancer Genome Atlas (TCGA) were assessed and subtyped based on the mRNA expression-based stemness index (mRNAsi). The correlations of cancer stemness with the immune microenvironment, tumor mutational burden (TMB) and N6-methyladenosine (m6A) RNA methylation regulators were analyzed. Weighted gene co-expression network analysis (WGCNA) was performed to identify the crucial stemness-related genes and modules. Furthermore, a prognostic expression signature was constructed using Lasso-penalized Cox regression analysis. The signature was validated via multiplex immunofluorescence staining of tissue samples in an independent cohort of 48 CRC patients.Results: This study suggests that high mRNAsi scores are associated with poor overall survival in stage Ⅳ CRC patients. Moreover, the levels of TMB and m6A RNA methylation regulators were positively correlated with mRNAsi scores, and low mRNAsi scores were characterized by increased immune activity in CRC. The analysis identified 2 key modules and 34 key genes as prognosis-related candidate biomarkers. Finally, a 3-gene prognostic signature (PARPBP, KNSTRN and KIF2C) was explored together with specific clinical features to construct a nomogram, which was successfully validated in an external cohort. Conclusions: There is a unique correlation between CSCs and the prognosis of CRC patients, and the novel biomarkers related to cell stemness could accurately predict the clinical outcomes of these patients.


2020 ◽  
Author(s):  
Chen Yang ◽  
Changhao Huang ◽  
Pengwei Zeng ◽  
Heyuan Huang ◽  
Zhikang Chen ◽  
...  

Abstract Background: B3GNT6 encodes the core 3 synthase in O-glycan biosynthesis. It is commonly expressed in the GI tract, while its clinical significance in colorectal cancer remains largely unknown.Methods: We gathered mRNA transcriptomic sequencing data from 3 Gene Expression Omnibus (GEO) datasets (GSE37182, GSE39582, GSE103512) and The Cancer Genome Atlas (TCGA) to compare the B3GNT6 mRNA level between colorectal cancer tissues and normal tissues and to evaluate its value as a prognostic marker. We further validated this in protein level using online database Human Protein Atlas and with immunohistochemical staining of B3GNT6 with our own cohort. Results: B3GNT6 expression was downregulated in colorectal cancer tissue compared with that in normal tissue in both mRNA and in protein level. Downregulation of B3GNT6 was associated with poor overall survival of colorectal cancer in GSE39582 and in TCGA database. Low B3GNT6 mRNA level was significantly associated with chromosome stable (CIN negative) and KRAS mutated group colorectal cancer patient. GSEA revealed that low B3GNT6 level in colorectal cancer is associated with upregulated proteasome activity.Conclusions: Downregulated B3GNT6 was correlated with poor overall survival of colorectal cancer patients. B3GNT6 could be used as a good prognostic marker in colorectal cancer.


Oncogene ◽  
2021 ◽  
Author(s):  
Cyrus Vaziri ◽  
Igor B. Rogozin ◽  
Qisheng Gu ◽  
Di Wu ◽  
Tovah A. Day

AbstractMutagenesis is a key hallmark and enabling characteristic of cancer cells, yet the diverse underlying mutagenic mechanisms that shape cancer genomes are not understood. This review will consider the emerging challenge of determining how DNA damage response pathways—both tolerance and repair—act upon specific forms of DNA damage to generate mutations characteristic of tumors. DNA polymerases are typically the ultimate mutagenic effectors of DNA repair pathways. Therefore, understanding the contributions of DNA polymerases is critical to develop a more comprehensive picture of mutagenic mechanisms in tumors. Selection of an appropriate DNA polymerase—whether error-free or error-prone—for a particular DNA template is critical to the maintenance of genome stability. We review different modes of DNA polymerase dysregulation including mutation, polymorphism, and over-expression of the polymerases themselves or their associated activators. Based upon recent findings connecting DNA polymerases with specific mechanisms of mutagenesis, we propose that compensation for DNA repair defects by error-prone polymerases may be a general paradigm molding the mutational landscape of cancer cells. Notably, we demonstrate that correlation of error-prone polymerase expression with mutation burden in a subset of patient tumors from The Cancer Genome Atlas can identify mechanistic hypotheses for further testing. We contrast experimental approaches from broad, genome-wide strategies to approaches with a narrower focus on a few hundred base pairs of DNA. In addition, we consider recent developments in computational annotation of patient tumor data to identify patterns of mutagenesis. Finally, we discuss the innovations and future experiments that will develop a more comprehensive portrait of mutagenic mechanisms in human tumors.


Author(s):  
Haitang Yang ◽  
Liang Zhao ◽  
Feng Yao ◽  
Yanyun Gao ◽  
Thomas M. Marti ◽  
...  

Abstract Background: Ferroptosis is an apoptosis-independent cell death program implicated in various diseases including cancer. Emerging evidence has demonstrated the promise of pharmacological induction of ferroptosis as a novel anti-cancer approach, but the molecular underpinnings of ferroptosis regulation and biomarkers associated with sensitivity to ferroptosis indcuers has been poorly defined. Methods: By implementing integrated pharmacogenomic analysis, we correlated the sensitivity of small-molecule compounds (n=481) against the transcriptomes of solid cancer cell lines (n=659). The potential of a drug compound to modulate ferroptosis was determined by significant (empirical p-value < 0.01) association of drug effectiveness with SLC7A11 expression. To establish generalized gene signatures for ferroptosis sensitivity and resistance, we interrogated drug effects of multiple ferroptosis inducers (n=7) with transcriptomic data of pan-solid cancer cells. Finally, the ferroptosis gene signature was applied to The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) project to identify cancer patients and cells that likely benefit from ferroptosis-based therapeutics. Results: We report, for the first time, the comprehensive identification of cancer drugs with the potential to induce ferroptosis and a generalized gene expression signature predicting ferroptosis response in pan-cancer. Informed by the findings, we reveal an unanticipated role for class I histone deacetylase (HDAC) in regulating ferroptosis and show that targeting HDAC significantly enhances the ferroptosis-promoting effect of Erastin in lung cancer cells. Moreover, our data indicate that small cell lung cancer (SCLC) and isocitrate dehydrogenase ( IDH )-mutant brain tumors are highly primed for ferroptosis, suggesting that relaunching ferroptosis might be an innovative strategy to target these malignancies. Conclusions: Expanding arsenal targeting aberrant ferroptosis and deciphering gene networks dictating ferroptosis sensitivity shed light on ferroptosis regulatory networks and may facilitate biomarker-guided stratification for ferroptosis-based therapy.


2019 ◽  
Vol 20 (12) ◽  
pp. 3100 ◽  
Author(s):  
Daniela Criscuolo ◽  
Francesco Morra ◽  
Riccardo Giannella ◽  
Aniello Cerrato ◽  
Angela Celetti

One of the most common malignancies in men is prostate cancer, for which androgen deprivation is the standard therapy. However, prostate cancer cells become insensitive to anti-androgen treatment and proceed to a castration-resistant state with limited therapeutic options. Therefore, besides the androgen deprivation approach, novel biomarkers are urgently required for specific targeting in this deadly disease. Recently, germline or somatic mutations in the homologous recombination (HR) DNA repair genes have been identified in at least 20–25% of metastatic castration-resistant prostate cancers (mCRPC). Defects in genes involved in HR DNA repair can sensitize cancer cells to poly(ADP-ribose) polymerase (PARP) inhibitors, a class of drugs already approved by the Food and Drug Administration (FDA) for breast and ovarian cancer carrying germline mutations in BRCA1/2 genes. For advanced prostate cancer carrying Breast cancer1/2 (BRCA1/2) or ataxia telengiectasia mutated (ATM) mutations, preclinical studies and clinical trials support the use of PARP-inhibitors, which received breakthrough therapy designation by the FDA. Based on these assumptions, several trials including DNA damage response and repair (DDR) targeting have been launched and are ongoing for prostate cancer. Here, we review the state-of-the-art potential biomarkers that could be predictive of cancer cell synthetic lethality with PARP inhibitors. The identification of key molecules that are affected in prostate cancer could be assayed in future clinical studies to better stratify prostate cancer patients who might benefit from target therapy.


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