Franziska Maria Schwarz, Daniel Martin Klotz, Ruming Yang, Melanie Brux, Frank Buchholz, Hani Harb, Theresa Link, Pauline Wimberger, Mirko Theis, Jan Dominik Kuhlmann
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引用次数: 0
Abstract
PARP-inhibitors (PARPi) are an integral part of ovarian cancer treatment. However, overcoming acquired PARPi resistance or increasing the benefit of PARPi in patients without homologous recombination deficiency (HRD) remains an unmet clinical need. We sought to identify genetic modulators of PARPi response, guiding pharmacological PARPi sensitization. CRISPR-Cas9 mediated loss-of-function screen with a focused sgRNA library revealed that DNA-demethylases JMJD1B/JMJD1C, targetable by the small inhibitor methylstat, promote PARPi resistance. Methylstat synergistically interacted with olaparib, and (re-)sensitized ovarian cancer cells to PARPi treatment, surpassing the efficacy of common demethylase inhibitors. Genetic knockout of JMJD1B and/or JMJD1C phenocopied the effect of methylstat in an additive manner. Validation studies revealed methylstat to be a universal PARPi-sensitizing drug, effective, regardless of PARPi resistance status or BRCA1 mutational background. Methylstat modulated clonal cancer dynamics by mitigating positive selection of PARPi-resistant or BRCA1-proficient cells under olaparib treatment. Using a model of PARPi-induced cellular toxicity, we showed that methylstat impairs cellular DNA repair, indicated by an increased susceptibility of ovarian cancer cells to olaparib-induced DNA double strand breaks after methylstat exposure. This study proposes the histone demethylase inhibitor methylstat as an epigenetic drug for overcoming PARPi-resistance or for increasing efficacy of PARPi beyond HRD in ovarian cancer patients.
期刊介绍:
Cancer Gene Therapy is the essential gene and cellular therapy resource for cancer researchers and clinicians, keeping readers up to date with the latest developments in gene and cellular therapies for cancer. The journal publishes original laboratory and clinical research papers, case reports and review articles. Publication topics include RNAi approaches, drug resistance, hematopoietic progenitor cell gene transfer, cancer stem cells, cellular therapies, homologous recombination, ribozyme technology, antisense technology, tumor immunotherapy and tumor suppressors, translational research, cancer therapy, gene delivery systems (viral and non-viral), anti-gene therapy (antisense, siRNA & ribozymes), apoptosis; mechanisms and therapies, vaccine development, immunology and immunotherapy, DNA synthesis and repair.
Cancer Gene Therapy publishes the results of laboratory investigations, preclinical studies, and clinical trials in the field of gene transfer/gene therapy and cellular therapies as applied to cancer research. Types of articles published include original research articles; case reports; brief communications; review articles in the main fields of drug resistance/sensitivity, gene therapy, cellular therapy, tumor suppressor and anti-oncogene therapy, cytokine/tumor immunotherapy, etc.; industry perspectives; and letters to the editor.