Ovarian cancer: strategies for overcoming resistance to chemotherapy

Agarwal, Roshan; Kaye, Stan B.

doi:10.1038/nrc1123

Cited by 1,026 publications

(912 citation statements)

References 106 publications

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“…However, while initially often responding with regression, most tumors relapse and develop resistance within less than a year. 17,18 Like other platinum compounds, carboplatin acts by forming crosslinks within DNA. 17 Platinum compounds form intrastrand DNA lesions but also interstrand crosslinks (ICLs) by covalently linking opposite DNA strands.…”

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confidence: 99%

Strong antitumor synergy between DNA crosslinking and HSP90 inhibition causes massive premitotic DNA fragmentation in ovarian cancer cells

et al. 2016

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All current regimens for treating ovarian cancer center around carboplatin as standard first line. The HSP90 inhibitor ganetespib is currently being assessed in advanced clinical oncology trials. Thus, we tested the combined effects of ganetespib and carboplatin on a panel of 15 human ovarian cancer lines. Strikingly, the two drugs strongly synergized in cytotoxicity in tumor cells lacking wild-type p53. Mechanistically, ganetespib and carboplatin in combination, but not individually, induced persistent DNA damage causing massive global chromosome fragmentation. Live-cell microscopy revealed chromosome fragmentation occurring to a dramatic degree when cells condensed their chromatin in preparation for mitosis, followed by cell death in mitosis or upon aberrant exit from mitosis. HSP90 inhibition caused the rapid decay of key components of the Fanconi anemia pathway required for repair of carboplatin-induced interstrand crosslinks (ICLs), as well as of cell cycle checkpoint mediators. Overexpressing FancA rescued the DNA damage induced by the drug combination, indicating that FancA is indeed a key client of Hsp90 that enables cancer cell survival in the presence of ICLs. Conversely, depletion of nuclease DNA2 prevented chromosomal fragmentation, pointing to an imbalance of defective repair in the face of uncontrolled nuclease activity as mechanistic basis for the observed premitotic DNA fragmentation. Importantly, the drug combination induced robust antitumor activity in xenograft models, again accompanied with depletion of FancA. In sum, our findings indicate that ganetespib strongly potentiates the antitumor efficacy of carboplatin by causing combined inhibition of DNA repair and cell cycle control mechanisms, thus triggering global chromosome disruption, aberrant mitosis and cell death. 6 This provides a strong rationale for HSP90 inhibitors in cancer therapy 7 and raises the possibility that HSP90 inhibitors can be used in combination with DNAdamaging chemotherapeutics. 8 Ovarian cancer is among the most common gynecological tumor types and carries the worst prognosis. HSP90 is highly expressed in advanced ovarian carcinoma 9 and thus constitutes a potential therapeutic drug target. 10 In support, HSP90 inhibitors were found effective against ovarian cancer in preclinical models, 11-14 alone or in combination with conventional chemotherapy. 15,16 Carboplatin is the key component of all current first-line therapies for ovarian carcinoma. However, while initially often responding with regression, most tumors relapse and develop resistance within less than a year. 17,18 Like other platinum compounds, carboplatin acts by forming crosslinks within DNA. 17 Platinum compounds form intrastrand DNA lesions but also interstrand crosslinks (ICLs) by covalently linking opposite DNA strands. Such ICLs represent major obstacles to the DNA replication fork 19 and are therefore considered the principal toxic lesion of carboplatin's mode of action. The ICLs can only be removed by a sophisticated DNA repair systemthe Fanconi ...

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confidence: 99%

Strong antitumor synergy between DNA crosslinking and HSP90 inhibition causes massive premitotic DNA fragmentation in ovarian cancer cells

et al. 2016

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“…Although a complete clinical response to optimal surgery and firstline chemotherapy (currently usually a platinum agent in combination with paclitaxel) is frequently achieved, the majority of women will relapse with recurrent disease that becomes refractory to further cytotoxic treatment and is essentially incurable. Understanding the mechanisms that underlie the emergence of drug resistance is critical for the development of novel treatments that can prevent or overcome drug resistance and thus improve survival (Vasey, 2003;Agarwal and Kaye, 2003).…”

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The E3 ubiquitin ligase EDD is an adverse prognostic factor for serous epithelial ovarian cancer and modulates cisplatin resistance in vitro

et al. 2008

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Despite a high initial response rate to first-line platinum/paclitaxel chemotherapy, most women with epithelial ovarian cancer relapse with recurrent disease that becomes refractory to further cytotoxic treatment. We have previously shown that the E3 ubiquitin ligase, EDD, a regulator of DNA damage responses, is amplified and overexpressed in serous ovarian carcinoma. Given that DNA damage pathways are linked to platinum resistance, the aim of this study was to determine if EDD expression was associated with disease recurrence and platinum sensitivity in serous ovarian cancer. High nuclear EDD expression, as determined by immunohistochemistry in a cohort of 151 women with serous ovarian carcinoma, was associated with an approximately two-fold increased risk of disease recurrence and death in patients who initially responded to first-line chemotherapy, independently of disease stage and suboptimal debulking. Although EDD expression was not directly correlated with relative cisplatin sensitivity of ovarian cancer cell lines, sensitivity to cisplatin was partially restored in platinum-resistant A2780-cp70 ovarian cancer cells following siRNA-mediated knockdown of EDD expression. These results identify EDD as a new independent prognostic marker for outcome in serous ovarian cancer, and suggest that pathways involving EDD, including DNA damage responses, may represent new therapeutic targets for chemoresistant ovarian cancer.

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“…In many tumors, the actively dividing cells account for only a small proportion of the total cancer cells, with the remainder of the cells being in a nonproliferating state, which consists of both G0 (quiescent cells) and G1 cells (3,4). Indeed, tumor cell populations in G0 range from 70-95%, among different types of cancer including epithelial ovarian cancer (OC) (5,6). In a study looking at 100 OC tumors, the average expression of Ki-67, a proliferation marker present in all stages of the cell cycle except cells arrested at G0 and early G1, was 30% (5, 7).…”

Section: Introductionmentioning

confidence: 99%

NSAIDs induce apoptosis in nonproliferating ovarian cancer cells and inhibit tumor growth in vivo

et al. 2012

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Ovarian cancer (OC) is one of the most lethal gynaecological cancers, which usually has a poor prognosis due to late diagnosis. A large percentage of the OC cell population is in a nonproliferating and quiescent stage, which poses a barrier to success when using most chemotherapeutic agents. Recent studies have shown that several nonsteroidal anti‐inflammatory drugs (NSAIDs) are effective in the treatment of OC. Furthermore, we have previously described the molecular mechanisms of NSAIDs' induction of cancer apoptosis. In this report, we evaluated various structurally distinct NSAIDs for their efficacies in inducing apoptosis in nonproliferating OC cells. Although several NSAIDs‐induced apoptosis, Flufenamic Acid, Flurbiprofen, Finasteride, Celocoxib, and Ibuprofen were the most potent NSAIDs inducing apoptosis. A combination of these agents resulted in an enhanced effect. Furthermore, we demonstrate that the combination of Flurbiprofen, which targets nonproliferative cells, and Sulindac Sulfide, that affects proliferative cells, strongly reduced tumor growth when compared with a single agent treatment. Our data strongly support the hypothesis that drug treatment regimens that target nonproliferating and proliferating cells may have significant efficacy against OC. These results also provide a rationale for employing compounds or even chemically modified NSAIDs, which selectively and efficiently induce apoptosis in cells during different stages of the cell cycle, to design more potent anticancer drugs. © 2012 IUBMB IUBMB Life, 64(7): 636–643, 2012

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Ovarian cancer: strategies for overcoming resistance to chemotherapy

Cited by 1,026 publications

References 106 publications

Strong antitumor synergy between DNA crosslinking and HSP90 inhibition causes massive premitotic DNA fragmentation in ovarian cancer cells

Strong antitumor synergy between DNA crosslinking and HSP90 inhibition causes massive premitotic DNA fragmentation in ovarian cancer cells

The E3 ubiquitin ligase EDD is an adverse prognostic factor for serous epithelial ovarian cancer and modulates cisplatin resistance in vitro

NSAIDs induce apoptosis in nonproliferating ovarian cancer cells and inhibit tumor growth in vivo

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