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Telomeric Allelic Imbalance Indicates Defective DNA Repair and Sensitivity to DNA-Damaging Agents

ABSTRACT: DNA repair competency is one determinant of sensitivity to certain chemotherapy drugs, such as cisplatin. Cancer cells with intact DNA repair can avoid the accumulation of genome damage during growth and also can repair platinum-induced DNA damage. We sought genomic signatures indicative of defective DNA repair in cell lines and tumors and correlated these signatures to platinum sensitivity. The number of subchromosomal regions with allelic imbalance extending to the telomere (NtAI) predicted cisplatin sensitivity in vitro and pathologic response to preoperative cisplatin treatment in patients with triple-negative breast cancer (TNBC). In serous ovarian cancer treated with platinum-based chemotherapy, higher levels of NtAI forecast a better initial response. We found an inverse relationship between BRCA1 expression and NtAI in sporadic TNBC and serous ovarian cancers without BRCA1 or BRCA2 mutation. Thus, accumulation of telomeric allelic imbalance is a marker of platinum sensitivity and suggests impaired DNA repair.

ORGANISM(S): Homo sapiens

PROVIDER: GSE28330 | GEO | 2012/03/22

SECONDARY ACCESSION(S): PRJNA139475

REPOSITORIES: GEO

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Telomeric Allelic Imbalance Indicates Defective DNA Repair and Sensitivity to DNA-Damaging Agents

Project description:DNA repair competency is one determinant of sensitivity to certain chemotherapy drugs, such as cisplatin. Cancer cells with intact DNA repair can avoid the accumulation of genome damage during growth and also can repair platinum-induced DNA damage. We sought genomic signatures indicative of defective DNA repair in cell lines and tumors and correlated these signatures to platinum sensitivity. The number of subchromosomal regions with allelic imbalance extending to the telomere (NtAI) predicted cisplatin sensitivity in vitro and pathologic response to preoperative cisplatin treatment in patients with triple-negative breast cancer (TNBC). In serous ovarian cancer treated with platinum-based chemotherapy, higher levels of NtAI forecast a better initial response. We found an inverse relationship between BRCA1 expression and NtAI in sporadic TNBC and serous ovarian cancers without BRCA1 or BRCA2 mutation. Thus, accumulation of telomeric allelic imbalance is a marker of platinum sensitivity and suggests impaired DNA repair. SNP data from 27 and 40 primary triple negative breast cancer tumor samples from two clinical trials treated with cisplatin and cisplatin + bevacizumab. Labeling, hybridization and data processing was performed by Affymetrix using 70k MIP arrays and 330k MIP arrays. In the cisplatin trial, matched normal samples based on blood from all patients and an additional three samples based on FFPE negative lymph nodes were used as references (30 normal references in total). In the cisplatin+bevacizumab trial, mathed normal samples based on blood from 10 patients were used as references.

2012-03-22 | E-GEOD-28330 | biostudies-arrayexpress

GenomicScarsInTnbcs_AGrigoriadis

Project description:Triple negative breast cancers (TNBCs) are characterised by a wide spectrum of genomic aberrations representing underlying repair defects that may be targeted therapeutically. However, means to measure these defects in tumours and an understanding of their effect on sensitivity to DNA damaging agents is limited. We sought to address this by establishing methods to trace underlying deficiencies in DNA repair processes using patterns of genomic instability. Here, we demonstrate that a pattern related to Homologous Recombination defects, allelic-imbalanced Copy Number Aberration, predicts response to platinum containing chemotherapeutics in TNBC patients. These patterns also enabled us to identify a meiotic gene HORMAD1, as a functional driver of allelic-imbalanced Copy Number Aberration and genomic instability in TNBC. Additionally, HORMAD1 expression is also a predictive marker of carboplatin response in TNBC. Mechanistically, expression of HORMAD1 in cell lines inhibited Homologous Recombination representing outÐof-context activation of its meiotic function.

2015-03-31 | E-MTAB-2626 | biostudies-arrayexpress

Tumor expression data from neoadjuvant trial of cisplatin monotherapy in triple negative breast cancer patients

2009-11-04 | GSE18864 | GEO

Tumor expression data from neoadjuvant trial of cisplatin monotherapy in triple negative breast cancer patients

Project description:Evidence suggests that BRCA1 mutation associated tumors have increased sensitivity to DNA damaging agents like cisplatin. Sporadic triple negative breast cancers (TNBC) have many phenotypic similarities to BRCA1 tumors and may have a similar sensitivity to cisplatin. We tested the efficacy of cisplatin monotherapy in 28 TNBC patients in a single arm neoadjuvant trial with outcome measured by pathologic treatment response quantified using the Miller-Payne scale. We used microarrays gene expression profiles to determine tumor subtype of each trial tumor sample and to test various expression signatures for association with pathologic response to cisplatin. Pretreatment tumor samples from the clinical trial (N=24 with adequate tissue) were used for RNA extraction, linear amplification, biotin labeling and hybridization to Affymetrix U133 plus 2.0 arrays. A reference set of 51 primary breast tumors representing all subtypes of breast cancer were processed in a similar manner to include linear amplification, and hybridized to Affymetrix arrays.

2009-11-04 | E-GEOD-18864 | biostudies-arrayexpress

Olaparib resistance and cisplatin responses in triple negative breast cancer

Project description:PARP inhibitor and platinum based drugs such as cisplatin are promising therapies for triple negative breast cancer and exploit the deficiencies in BRCA1 or BRCA2, or homologous recombination repair defects. However, PARP inhibitor resistance is proven to be a major clinical problem. Acquired PARP inhibitor resistance has been linked with co-resistance to platinum-based drugs. To determine how acquired olaparib resistance affects cisplatin response and whether this is influenced by their BRCA1 status, we performed RNAseq transcriptome analysis of isogenic triple negative breast cancer models of olaparib resistance with normal and mutant BRCA1.

2021-07-22 | GSE165914 | GEO

Homo sapiens

Project description:Telomeric Allelic Imbalance Indicates Defective DNA Repair and Sensitivity to DNA-Damaging Agents

| PRJNA139475 | ENA

Epigenetic regulation of the homeobox gene MSX1 associates with platinum resistant disease in high grade serous epithelial ovarian cancer

Project description:Introduction: Although High Grade Serous Ovarian Cancer (HGSOC) is considered a chemo-responsive disease, a proportion of patients do not respond to platinum-based chemotherapy at presentation or have progression-free survival of <6 months. Validated biomarkers of lack of response would enable alternative treatment stratification for these patients and identify novel mechanisms of resistance. Methods: Differential DNA methylation was investigated in independent tumour sets using Illumina 27K HumanMethylation arrays and validated by bisulphite pyrosequencing. Gene expression was by Affymetrix arrays and qRT-PCR. The role of Msh homeobox 1 (MSX1) in drug sensitivity was investigated by gene reintroduction into ovarian cancer cell lines. Results: CpG sites at contiguous genomic locations within the MSX1 gene have significantly lower levels of methylation in HGSOC which recur by 6 months compared to after 12 months and/or with RECIST response (p<0.05, q<0.05). A decrease in methylation at these intragenic CpG sites was significantly correlated with decreased MSX1 gene expression. Low expression of MSX1 was associated with poor progression-free survival independent of known clinical prognostic features (p=0.014). Three mutant or wild-type TP53 expressing ovarian cancer cell lines, resistant to cisplatin, have reduced MSX1 expression compared to matched parental, platinum sensitive, lines. Re-expression of MSX1 in resistant lines led to cisplatin sensitisation, increased apoptosis, increased p21 and BAX expression. However, in two TP53-null cell lines, MSX1 failed to change cisplatin sensitivity. Conclusion: Hypomethylation of MSX1 is a biomarker of resistant HGSOC disease at presentation and identifies a novel mechanism of platinum drug resistance. Bisulphite converted DNA from the 86 samples were hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2

2015-11-26 | E-GEOD-75414 | biostudies-arrayexpress

Mutational signature-based identification of DNA repair deficient gastroesophageal adenocarcinomas for therapeutic targeting

Project description:Homologous recombination (HR) and nucleotide excision repair (NER) are the two most frequently disabled DNA repair pathways in cancer. HR-deficient breast, ovarian, pancreatic and prostate cancers respond well to platinum chemotherapy and PARP inhibitors. However, the frequency of HR deficiency in gastric and esophageal adenocarcinoma (GEA) still lacks diagnostic and functional validation. Using whole exome and genome sequencing data, we found that a significant subset of GEA, but very few colorectal adenocarcinomas, show evidence of HR deficiency by mutational signature analysis (HRD score). High HRD gastric cancer cell lines demonstrated functional HR deficiency by RAD51 foci assay and increased sensitivity to platinum chemotherapy and PARP inhibitors. Of clinical relevance, analysis of three different GEA patient cohorts demonstrated that platinum treated HR deficient cancers had better outcomes. A gastric cancer cell line with strong sensitivity to cisplatin showed HR proficiency but exhibited NER deficiency by two photoproduct repair assays. Single-cell RNA-sequencing revealed that, in addition to inducing apoptosis, cisplatin treatment triggered ferroptosis in a NER-deficient gastric cancer, validated by intracellular GSH assay. Overall, our study provides preclinical evidence that a subset of GEAs harbor genomic features of HR and NER deficiency and may therefore benefit from platinum chemotherapy and PARP inhibitors.

2024-02-23 | GSE256301 | GEO

Evaluation of poly (ADP) ribose polymerase (PARP) inhibitor, veliparib (ABT-888), in combination with platinum, etoposide and radiation in small cell lung cancer

Project description:Veliparib showed limited single agent cytotoxicity but selectively potentiated (≥50% reduction in IC50) cisplatin, carboplatin and etoposide in vitro in 5 of 9 SCLC cell lines. Veliparib with cisplatin, etoposide or with both cisplatin and etoposide showed greater delay in tumor growth than chemotherapy alone in H146 but not H128. The potentiating effect of veliparib was associated with in vitro cell line sensitivity to cisplatin (CC=0.672; p=0.048) and DNA-PKcs protein modulation. Gene expression profiling identified differential expression of a 5-gene panel (GLS, UBEC2, HACL1, MSI2 and LOC100129585) in cell lines with relatively greater sensitivity to platinum and veliparib combination. Veliparib potentiates standard cytotoxic agents against SCLC in a cell specific manner. This potentiation correlates with platinum sensitivity, DNA-PKcs expression and a 5-gene expression profile.

2014-12-31 | GSE55830 | GEO

Unexpected roles of ATP11B in platinum resistance

Project description:Platinum compounds display clinical activity against a wide variety of solid tumors. However, resistance to these agents is a major limitation in cancer therapy. Reduced platinum uptake and increased platinum export are examples of resistance mechanisms that limit the extent of DNA damage. Here, we report the discovery and characterization of the role of ATP11B, a P-type ATPase membrane protein, in cisplatin resistance. ATP11B gene silencing restored the sensitivity of ovarian cancer cell lines to cisplatin in vitro. Combined therapy of cisplatin and ATP11B-siRNA significantly decreased cancer growth in mice bearing ovarian tumors derived from cisplatin-sensitive and -resistant cells. In vitro mechanistic studies on cellular platinum content and cisplatin efflux-kinetics indicated that ATP11B enhances the export of cisplatin from cells. The co-localization of ATP11B with fluorescent cisplatin and with vesicular trafficking proteins such as syntaxin-6 (STX6) and vesicular associated membrane protein 4 (VAMP4) strongly suggests that ATP11B contributes to secretory vesicular transport of cisplatin from Golgi to plasma membrane. In conclusion, silencing ATP11B expression might be a therapeutic strategy to overcome cisplatin resistance. We performed the transfection of control-siRNA and ATP11B-siRNA to both cisplatin-sensitive A2780-PAR and cisplatin-resistant A2780-CP20 cells respectively.

2013-01-23 | E-GEOD-43694 | biostudies-arrayexpress

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