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Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy.

ABSTRACT: BACKGROUND:Poly(ADP-ribose) polymerase inhibitors (PARPis) specifically target homologous recombination deficiency (HRD) cells and display good therapeutic effect in women with advanced-stage BRCA1/2-mutated breast and epithelial ovarian cancer (EOC). However, about 50% of high grade serous ovarian cancers (HGSOC) present with HRD due to epigenetic BRCA1 inactivation, as well as genetic/epigenetic inactivation(s) of other HR genes, a feature known as "BRCAness". Therefore, there is a potential for extending the use of PARPis to these patients if HR status can be identified. METHODS:We have developed a 3D (spheroid) functional assay to assess the sensitivity of two PARPis (niraparib and olaparib) in ascites-derived primary cell cultures (AsPCs) from HGSOC patients. A method for AsPCs preparation was established based on a matrix (agarose), allowing for easy isolation and successive propagation of monolayer and 3D AsPCs. Based on this method, we performed cytotoxicity assays on 42 AsPCs grown both as monolayers and spheroids. RESULTS:The response to PARPis treatment in monolayer AsPCs, was significantly higher, compared to 3D AsPCs, as 88% and 52% of the monolayer AsPCs displayed sensitivity to niraparib and olaparib respectively, while 66% of the 3D AsPCs were sensitive to niraparib and 38% to olaparib, the latter being more consistent with previous estimates of HRD (40%-60%) in EOC. Moreover, niraparib displayed a significantly stronger cytotoxic effect in both in 3D and monolayer AsPCs, which was confirmed by consecutive analyses of the HR pathway activity (?H2AX foci formation) in PARPis-sensitive and resistant AsPCs. Global gene expression comparison of 6 PARPi-resistant and 6 PARPi-sensitive 3D AsPCs was indicative for the predominant downregulation of numerous genes and networks with previously demonstrated roles in EOC chemoresistance, suggesting that the PARPis-sensitive AsPCs could display enhanced sensitivity to other chemotherapeutic drugs, commonly applied in cancer management. Microarray data validation identified 24 potential gene biomarkers associated with PARPis sensitivity. The differential expression of 7 selected biomarkers was consecutively confirmed by immunohistochemistry in matched EOC tumor samples. CONCLUSION:The application of this assay and the potential biomarkers with possible predictive significance to PARPis therapy of EOC patients now need testing in the setting of a clinical trial.

SUBMITTER: Sheta R

PROVIDER: S-EPMC7678187 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy.

Sheta Razan R Bachvarova Magdalena M Plante Marie M Renaud Marie-Claude MC Sebastianelli Alexandra A Gregoire Jean J Navarro Jamilet Miranda JM Perez Ricardo Bringas RB Masson Jean-Yves JY Bachvarov Dimcho D

Journal of translational medicine 20201119 1

<h4>Background</h4>Poly(ADP-ribose) polymerase inhibitors (PARPis) specifically target homologous recombination deficiency (HRD) cells and display good therapeutic effect in women with advanced-stage BRCA1/2-mutated breast and epithelial ovarian cancer (EOC). However, about 50% of high grade serous ovarian cancers (HGSOC) present with HRD due to epigenetic BRCA1 inactivation, as well as genetic/epigenetic inactivation(s) of other HR genes, a feature known as "BRCAness". Therefore, there is a pot ...[more]

PMID: 33213473

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Project description:Epithelial ovarian cancer (EOC) is the most serious of all gynecological cancers, mainly due to its asymptomatic nature and the resulting lack of early diagnosis. Cells with defects in DNA repair accumulate genetic abnormalities and may progress to become malignant. However, this DNA repair deficiency makes tumor cells vulnerable to further compromise by therapeutic targeting of other associated pathways, using agents such as poly-ADP ribose polymerase (PARP) inhibitors (PARPIs). A major challenge facing the use of PARPIs is the paucity of functional assays/biomarkers to identify HGSOC patients who may benefit from these agents, in particular the subgroup with non-BRCA-mutant, HR-deficient cancers. Our study presents a predictive tool which may help identify sporadic HGSOC patients, most likely to respond to PARPIs therapy. We have successfully developed and employed a functional 3D assay to test PARPIs sensitivity in EOC based on ascites-derived primary cell cultures (AsPCs) from EOC patients. Our data showed that this approach can better mimic primary tumor response to PARPIs treatments. We have successfully grown 42 AsPCs, and have prepared spheroid cultures from AsPCs using 3D-Biomatrix technology. We were able to monitor the cytotoxic effect on AsPCs spheroids of each of the drugs olaparib (Astra- Zeneca) and niraparib (Tesaro, licensed from Merck). Our results showed that AsPCs appear to be much more sensitive to niraparib compared to olaparaib. The cytotoxic effect observed by the two drugs was confirmed by analysis of γH2AX foci formation. Data demonstrated γH2AX foci to significantly increase in cell lines that are sensitive to the drug treatments. Consecutively, epithelial-to-mesenchymal transition (EMT) was also assessed in resistant vs. sensitive cell lines. Our results indicate that PARP inhibition can inhibit the acquisition of an EMT phenotype in sensitive cell lines, but not in resistant cell lines. Moreover, global gene and microRNA expression profiling of PARPI-R and PARPI-S spheroid cultures identifies gene/mRNA biomarkers, associated with PARPI sensitivity. We believe our predictive tool has helped classify genes that can be clinically relevant in identifying PARP inhibitor sensitivity in ovarian cancer.

Project description:Unlabelled: High-grade serous ovarian cancer is characterized by genomic instability, with one half of all tumors displaying defects in the important DNA repair pathway of homologous recombination. Given the action of poly(ADP-ribose) polymerase (PARP) inhibitors in targeting tumors with deficiencies in this repair pathway by loss of BRCA1/2, ovarian tumors could be an attractive population for clinical application of this therapy. PARP inhibitors have moved into clinical practice in the past few years, with approval from the Food and Drug Administration (FDA) and European Medicines Agency (EMA) within the past 2 years. The U.S. FDA approval of olaparib applies to fourth line treatment in germline BRCA-mutant ovarian cancer, and European EMA approval to olaparib maintenance in both germline and somatic BRCA-mutant platinum-sensitive ovarian cancer. In order to widen the ovarian cancer patient population that would benefit from PARP inhibitors, predictive biomarkers based on a clear understanding of the mechanism of action are required. Additionally, a better understanding of the toxicity profile is needed if PARP inhibitors are to be used in the curative, rather than the palliative, setting. We reviewed the development of PARP inhibitors in phase I-III clinical trials, including combination trials of PARP inhibitors and chemotherapy/antiangiogenics, the approval for these agents, the mechanisms of resistance, and the outstanding issues, including the development of biomarkers and the rate of long-term hematologic toxicities with these agents.Implications for practiceThe poly(ADP-ribose) polymerase (PARP) inhibitor olaparib has recently received approval from the Food and Drug Administration (FDA) and European Medicines Agency (EMA), with a second agent (rucaparib) likely to be approved in the near future. However, the patient population with potential benefit from PARP inhibitors is likely wider than that of germline BRCA mutation-associated disease, and biomarkers are in development to enable the selection of patients with the potential for clinical benefit from these agents. Questions remain regarding the toxicities of PARP inhibitors, limiting the use of these agents in the prophylactic or adjuvant setting until more information is available. The indications for olaparib as indicated by the FDA and EMA are reviewed.

Dataset Information

Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy.

Publications

Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy.

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