Resistant Ovarian Carcinoma Research Articles

A multicentric single-arm phase II clinical trial to evaluate safety and efficacy of the combination of olaparib and PLD for platinum resistant ovarian primary peritoneal carcinoma and fallopian tube cancer patients: The GEICO-1601 ROLANDO trial—A trial in resistant ovarian cancer with olaparib and pegylated liposomal doxorubicin.

TPS5610Background: Olaparib is a PARP-inhibitor that has demonstrated efficacy in ovarian cancer in both platinum-sensitive and platinum-resistant relapse. BRCA mutations have been identified as an...

A multicenter phase II study of the efficacy and safety of quisinostat (an HDAC inhibitor) in combination with paclitaxel and carboplatin chemotherapy (CT) in patients (pts) with recurrent platinum resistant high grade serous epithelial ovarian, primarily peritoneal or fallopian tube carcinoma cancer (OC).

5541 Background: Quisinostat is an orally bioavailable potent pan-histone deacetylase inhibitor. Combinations of HDAC inhibitors with paclitaxel or cisplatin demonstrate promising results in preclinical models with cisplatin and paclitaxel resistant OC. In phase Ib study the dosage of Quisinostat in combination of paclitaxel and carboplatin recommended for the phase II study was 12 mg. We report results of the phase II study of Quisinostat in combination with paclitaxel and carboplatin in pts with recurrent platinum resistantOC. Methods: the main inclusion criteria was tumor progression observed not less than 1 month and no more than 6 months after completion of the planned number of cycles of 1st line platinum/paclitaxel based CT. Quisinostat was administered at dose 12 mg p.o. each 3 week cycle on Days 1, 3, 5, 7, 9, 11 with of paclitaxel (175 mg/m2) and carboplatin (AUC5) on Day 7 of each cycle, for 2ndline. Pts received up to 6 cycles. The primary efficacy endpoint is the objective response rate (ORR) verified by the ICR. The secondary endpoints include safety, progression free survival (PFS) and overall survival. The study design implies the use of the two-stage Simon model: 29 patients who underwent treatment would provide 80% power for hypothesis testing in order to frequency of the ORR 30% (α = 0.05). Results: 31 pts were enrolled (30 pts evaluated). Median age was 57 years. Twenty one pts (67.7%) received all 6 cycles of therapy. ORR was 50.0% (15 pts). Median duration of response was 5 months (4.2-5.7). Median PFS - 6 months (95%CI 4.4-7.6). Any SAE were seen in 16.1% pts, AE of grade 3 and 4 – in 71% and 48.4% pts temporarily discontinued therapy due to AE. Dose reduction of CT due to AE was performed in 22.6% pts. The most common adverse events were neutropenia – 67,7%, nausea – 61.3%, weakness – 29%, thrombocytopenia – 22.6%, neuropathy – 19.4%, vomiting – 19.4%. Conclusions: Quisinostat in combination with paclitaxel and carboplatin in pts with recurrent platinum resistant ovarian cancer showed high efficacy and good tolerability Clinical trial information: NCT02948075.

Reversion of P-gp-Mediated Drug Resistance in Ovarian Carcinoma Cells with PHPMA-Zosuquidar Conjugates.

Inhibition of P-glycoprotein (P-gp) transporter is an attractive approach for the reversion of cancer-associated multidrug resistance (MDR). Poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA)-based carriers that are able to release the anticancer drug doxorubicin in the lysosomes have shown promise to reduce P-gp mediated resistance. This is attributed to the release of the drug in close proximity to the nucleus and distant from the P-gp transporter. This work presents a strategy to maximize P-gp inhibition and enhance doxorubicin cytotoxicity in cancer cells by using a dual functional PHPMA conjugate carrying both the anticancer drug doxorubicin and the P-glycoprotein inhibitor zosuquidar (Zos). While doxorubicin was connected to the polymer backbone via a lysosomally cleavable spacer, the P-gp inhibitor Zos was attached by a hydrazone linker in order to promote release in the early stage of the endocytic process and maximize its cytosolic concentration in proximity of the P-gp transporter. Following Zos modification and determination of its ability to inhibit P-gp, conjugation to the PHPMA polymer backbone resulted in enhanced doxorubicin cytotoxicity in resistant A2780ADR ovarian carcinoma cells. Finally, the incorporation of both Dox and Zos in a single polymer carrier enhanced P-gp inhibition as compared to a control PHPMA conjugate containing only Dox.

The reversal of multidrug resistance in ovarian carcinoma cells by co-application of tariquidar and paclitaxel in transferrin-targeted polymeric micelles

In this study, a transferrin (Tf)-modified polyethylene glycol-phosphatidyl ethanolamine (PEG-PE)-based micellar delivery system containing paclitaxel (PTX) and tariquidar (TRQ), a potent third generation P-gp inhibitor, was prepared. The nanoformulation was evaluated by targeting efficiency, cellular association, cellular internalization pathway and cytotoxicity for reversal of PTX resistance on two multidrug resistant (MDR) ovarian carcinoma cell lines, SKOV-3TR and A2780-Adr. PTX and TRQ are both hydrophobic compounds. They were successfully encapsulated into the micellar structure containing vitamin E as the encapsulation enhancer. The Tf-targeted micelles were internalized mainly via clathrin-dependent endocytosis by both cell lines. For SKOV-3TR, additional mechanisms including caveolin-dependent endocytosis and macropinocytosis were found to play a significant role. The PTX cytotoxicity against the SKOV-3TR and A2780-Adr MDR cells was increased significantly in the presence of micellar encapsulation. However, unlike the A2780-Adr cell line, the Tf-targeting effect was significant on SKOV-3TR cells when co-administrated with TRQ. Penetration of the Tf-targeted micelles in a cancer cell spheroid culture was also investigated.

Dual inhibition of ATR and ATM potentiates the activity of trabectedin and lurbinectedin by perturbing the DNA damage response and homologous recombination repair.

Trabectedin (Yondelis®, ecteinascidin-743, ET-743) is a marine-derived natural product approved for treatment of advanced soft tissue sarcoma and relapsed platinum-sensitive ovarian cancer. Lurbinectedin is a novel anticancer agent structurally related to trabectedin. Both ecteinascidins generate DNA double-strand breaks that are processed through homologous recombination repair (HRR), thereby rendering HRR-deficient cells particularly sensitive. We here characterize the DNA damage response (DDR) to trabectedin and lurbinectedin in HeLa cells. Our results show that both compounds activate the ATM/Chk2 (ataxia-telangiectasia mutated/checkpoint kinase 2) and ATR/Chk1 (ATM and RAD3-related/checkpoint kinase 1) pathways. Interestingly, pharmacological inhibition of Chk1/2, ATR or ATM is not accompanied by any significant improvement of the cytotoxic activity of the ecteinascidins while dual inhibition of ATM and ATR strongly potentiates it. Accordingly, concomitant inhibition of both ATR and ATM is an absolute requirement to efficiently block the formation of γ-H2AX, MDC1, BRCA1 and Rad51 foci following exposure to the ecteinascidins. These results are not restricted to HeLa cells, but are shared by cisplatin-sensitive and -resistant ovarian carcinoma cells. Together, our data identify ATR and ATM as central coordinators of the DDR to ecteinascidins and provide a mechanistic rationale for combining these compounds with ATR and ATM inhibitors.

Abstract B10: Noninvasive pharmacodynamic markers of the dual mTORC1/2 inhibitor AZD2014 in combination with paclitaxel, in cisplatin-resistant ovarian carcinoma xenografts

Abstract Background: The PI3K/AKT/mTOR pathway is known to regulate glucose metabolism, proliferation and apoptosis, hence the inhibition of mTOR is expected have impact on these important mechanisms of tumor growth and survival. Studies of cancer metabolism following mTOR inhibition reported to date have only been carried out on allosteric mTOR inhibitors which selectively inhibit the activity of mTORC1. The metabolic changes associated with dual mTORC1 and 2 inhibitions remain unknown. AZD2014 is a dual mTORC1/2 inhibitor. The aims of this study are to (i) examine the effects on tumor metabolism following mTORC1/2 inhibition alone and in combination with paclitaxel, (ii) to develop a non-invasive pharmacodynamic (PD) biomarker for tumor response. Methods: We investigated the effects of AZD2014 alone (A: 50mg/kg/3 days/week po), paclitaxel alone (P: 20mg/kg/1 day/week ip) and the combination of AZD2014 and paclitaxel (A+P: same doses) on tumor growth, signal transduction (pSer473-AKT, pSer240/244-S6) and apoptosis (cleaved PARP) in a cisplatin resistant ovarian (A2780CisR) carcinoma xenograft model following 2 weeks of treatment. Metabolic profiles of A2780CisR tumor extracts after 2 weeks of treatment were also measured by high resolution in vitro 1H- and 31P-MRS. In order to develop early non-invasive PD markers of tumor response, in vivo 1H-MRS before and after 3 days of treatment were also performed. Results: Growth and molecular response- Following two weeks of treatment, tumor volumes of the A2780CisR xenografts increased by 280±100% in A+P (p<0.05; compared to vehicle-controls (V)), 420±160% in A (not significant compared to V (ns)), 730±180% in P (ns) and 560±20% in V. Reduced pSer473-AKT and pSer240/244-S6 protein levels and increased cleaved-PARP expression were observed in A- and A+P-treated xenografts consistent with mTORC1/2 inhibition and induction of apoptosis, respectively. In vitro 1H- and 31P-MRS of tumor extracts- Similar significant increases in branched-chain amino acids (p<0.03), glutamine (p<0.002), tyrosine (p<0.0001), phenylalanine (p<0.02) and glucose (p<0.03) were found in A- and A+P-treated tumors when compared with V. Significant decreases in phosphocholine (PC, p<0.002), glycero-phosphocholine (GPC, p<0.002), phosphoethanolamine (PE, p<0.02) and ATP (p<0.003), together with reduced expression of choline kinase, were only seen in A+P-treated tumors. An increase in threonine (p<0.03) was only observed in P- and A+P-treated tumors compared with V. In vivo 1H-MRS- The reduction in phospholipid metabolites (PC, GPC and PE) following A+P treatment was confirmed in vivo with a significant decrease in the ratio of total choline/water signal (p=0.04) observed at the early time-point of 3 days of treatment. Conclusions: A+P is effective in preclinical ovarian tumors, with additive growth inhibition and increased apoptosis. Very few metabolic changes were observed in P-treated tumors compared with V. The non-phospholipid changes in the metabolic profiles of A- and A+P-treated tumors are consistent with previous findings where similar metabolic profiles were found following mTOR inhibition (1). A+P treatment also caused decreases in PC (associated with reduced choline kinase expression) and other choline-related metabolites and these phospholipid changes may have potential as surrogate non-invasive markers for determining tumor response following AZD2014 and paclitaxel combination treatment. (1) Lin et al. Cell Symposia: Angiogenesis, Metabolic Regulation, and Cancer Biology in association with VIB, Belgium 2012. This work is supported by the CR-UK and EPSRC Cancer Imaging Centre in association with the MRC and Department of Health (England) grants C1060/A10334 and C1060/A16464, NHS funding to the NIHR Biomedical Research Centre. MOL is an NIHR Senior Investigator. Citation Format: Anne-Christine LF Wong Te-Fong, Efthymia Papaevangelou, Martin O. Leach, Udai Banerji, Yuen-Li Chung. Noninvasive pharmacodynamic markers of the dual mTORC1/2 inhibitor AZD2014 in combination with paclitaxel, in cisplatin-resistant ovarian carcinoma xenografts. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr B10.

Proadifen sensitizes resistant ovarian adenocarcinoma cells to cisplatin.

Proadifen (SKF-525A) is a P450 monooxygenase inhibitor with potential anti-proliferative activity and the ability to potentiate the toxicity of hypericin-mediated photodynamic therapy and mitoxantrone via alteration of ABC transport proteins. Elevated expression of some ABC transporters may also determine the efficacy of cisplatin-based chemotherapy. Thus, the purpose of this study was to investigate the ability of proadifen to sensitize A2780 and A2780cis ovarian cancer cells to cisplatin (CDDP). Herein, we show for the first time that proadifen sensitized resistant ovarian cancer cells to CDDP-induced cell death. The chemosensitizing effect of proadifen on CDDP action was also confirmed by MTT assays in multicellular spheroids. The possible mechanisms responsible for the enhanced cytotoxicity of proadifen/CDDP combined treatment may be attributed to a decrease of reduced relative glutathione levels, downregulation of multidrug resistance-associated proteins 1 and 2 (MRP1, MRP2) and attenuation of survivin expression. Taken together, our results indicate that proadifen is a promising compound for further in vivo experiments related to overcoming multidrug resistance and sensitization of resistant ovarian carcinoma to CDDP.

Enhanced anti-hyperproliferative activity of human thymidylate synthase inhibitor peptide by solid lipid nanoparticle delivery

Recently, octapeptide LSCQLYQR (LRp), reducing growth of cis-platinum (cDDP) resistant ovarian carcinoma cells by inhibiting the monomer–monomer interface of the human enzyme thymidylate synthase, has been identified. As the peptide is not able to cross the cell membrane it requires an appropriate delivery system. In this work the application of SLNs, biocompatible and efficient tools for the intracellular drug transport, applied especially for lipophilic drugs, was exploited for the delivery of the hydrophilic peptide LRp. SLNs formulated in the absence/presence of small amount of squalene showed dimensions below 150nm, negative zeta potential and good stability to the freeze-drying process. Even though the particles formulated with squalene exhibited a less ordered crystal lattice and a lower surface hydrophobicity, a rapid drug release from these nanocarriers occurred as a result of the relevant expulsion of the drug from the lipid core during lipid crystallization. On the contrary, SLNs formulated in the absence of squalene were able to incorporate more stably the peptide showing considerable cytotoxic effect on cDDP resistant C13* ovarian carcinoma cell line at concentration 50 times lower than that used previously with a marketed delivery system. From the cell cycle analysis by the propidium iodide test in SLNs-peptide treated cancer cells an increase of apoptosis percentage was observed, indicating that SLNs were able to carry efficiently the peptide until its enzymatic target.

MicroRNA-133b targets glutathione S-transferase π expression to increase ovarian cancer cell sensitivity to chemotherapy drugs.

BackgroundAccumulating studies reveal that aberrant microRNA (miRNA) expression can affect the development of chemotherapy drug resistance by modulating the expression of relevant target proteins. The aim of this study was to investigate the role of miR-133b in the development of drug resistance in ovarian cancer cells.MethodsWe examined the levels of miR-133b expression in ovarian carcinoma tissues and the human ovarian carcinoma cell lines (A2780, A2780/DDP and A2780/Taxol, respectively). We determined the cell viability of these cell lines treated with cisplatin or paclitaxel in the presence or absence of miR-133b or anti-miR-133b transfection using the MTT assay. Reverse transcription polymerase chain reaction and Western blotting were used to assess the mRNA and protein expression levels of two drug-resistance-related genes: glutathione S-transferase (GST)-π and multidrug resistance protein 1 (MDR1). The dual-luciferase reporter assay was used to detect the promoter activity of GST-π in the presence and absence of miR-133b.ResultsThe expression of miR-133b was significantly lower in primary resistant ovarian carcinomas than in the chemotherapy-sensitive carcinomas (P<0.05), and the same results were found in primary resistant ovarian cell lines (A2780/Taxol and A2780/DDP) compared to the chemotherapy-sensitive cell line (A2780; P<0.05). Following miR-133b transfection, four cell lines showed increased sensitivity to paclitaxel and cisplatin, while anti-miR-133b transfection reduced cell sensitivity to paclitaxel and cisplatin. Dual-luciferase reporter assay showed that miR-133b interacted with the 3′-untranslated region of GST-π. Compared to controls, the mRNA and protein levels of MDR1 and GST-π were downregulated after miR-133b transfection and upregulated after anti-miR-133b transfection.ConclusionMicroRNA-133b may reduce ovarian cancer drug resistance by silencing the expression of the drug-resistance-related proteins, GST-π and MDR1. In future, the combination of miR-133b with chemotherapy agents may prevent the development of drug resistance in ovarian cancers.

Methylation-associated Has-miR-9 deregulation in paclitaxel- resistant epithelial ovarian carcinoma.

BackgroundDrug resistance is still one of the key causes of death in epithelial ovarian carcinoma (EOC) patients, however there are very few strategies to reverse chemoresistance. Here we try to clarify whether and how miR-9 takes part in the regulation of paclitaxel sensitivity.MethodsmiR-9 expressions in EOC cells and tissues were detected by Realtime PCR. The target of miR-9 was validated through dual luciferase reporter assay and Western Blot. Methylation study, RNAi technique and cytotoxicity assay were used to determine the intrinsic mechanism of miR-9 in paclitaxel sensitivity regulation.ResultsmiR-9 is down-regulated in paclitaxel resistant EOC. The patients with lower miR-9, Grade 3, Stage III –IV and suboptimal surgery present shorter survival time. miR-9 and suboptimal surgery are independent prognostic factors of EOC. Modulating miR-9 expression could change paclitaxel sensitivity of EOC cells. CCNG1, validated as a direct target of miR-9, mediates paclitaxel resistance. miR-9-1 and 3 gene hypermethylation would decrease miR-9 expression, while demethylation of miR-9 gene could restore miR-9 expression and improve paclitaxel sensitivity in chemoresistance EOC cells. Furthermore, methylation-associated miR-9 deregulation in EOC cells could be induced by paclitaxel exposure.ConclusionsMethylation-associated miR-9 down-regulation is probably one of the key mechanisms for paclitaxel resistance in EOC cells, via targeting CCNG1. Our findings may also provide a new potential therapeutic target to reverse paclitaxel resistance in EOC patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1509-1) contains supplementary material, which is available to authorized users.

Dichlorido-platinum(II) complexes with kinetin derivatives as promising cytotoxic agents avoiding resistance of cancer cells: Contrasting results between cisplatin and oxaliplatin analogues

With the aim to study the anticancer potential and compare the influence of different leaving groups, dichlorido and oxalato (ox) platinum(II) complexes involving di- and tri-substituted derivatives of a plant hormone kinetin (N6-furfuryladenine; Ln) were prepared: cis-[PtCl2(L1)2]·H2O (1), trans-[PtCl2(L1)2] (1a), cis-[PtCl2(L2)2]·0.75H2O (2), and [Pt(L1)2(ox)] (3), [Pt(L2)2(ox)] (4), with 2-chloro-N6-furfuryl-9-isopropyladenine (L1) and 2-chloro-N6-(5-methylfurfuryl)-9-isopropyladenine (L2). The complexes were structurally characterized by elemental and thermal analyses, FT-IR and 1H, 13C, 15N and 195Pt NMR spectroscopy, ESI+ mass spectrometry, conductivity measurements as well as single crystal X-ray diffraction (for 1). The Ln carrier ligands act as monodentate N-donors coordinated to the platinum(II) centre, which reveals a slightly distorted square-planar geometry. All the prepared complexes were screened for their in vitro cytotoxicity against breast adenocarcinoma (MCF7) and osteosarcoma (HOS) human cancer cell lines. This preliminary study identified only the cis-dichlorido-Pt(II) complexes 1, 2 as cytotoxic agents. These two complexes were thus further evaluated for in vitro cytotoxicity against malignant melanoma (G-361), cervix epitheloid carcinoma (HeLa), cisplatin sensitive (A2780) and resistant (A2780R) ovarian carcinoma human cancer cell lines. Most importantly, the obtained results showed that the cis-[PtCl2(Ln)2]·xH2O complexes were able to circumvent cisplatin resistance in A2780R cells while additionally being significantly more cytotoxic against A2780 than cisplatin, as demonstrated by the resistance factors IC50(A2780R)/IC50(A2780) equal to 0.87 for 1; 0.48 for 2 as compared to 2.25 for cisplatin. The complexes were furthermore comparably active against HOS, MCF7, G-361 cells as cisplatin. In order to address the contrasting cytotoxic results of the cisplatin (1, 2) and oxaliplatin (3, 4) analogues, their possible fate in the physiological environment, focusing on the hydrolytic stability and interactions with glutathione and 5′-guanosine monophosphate, was studied by means of 1H NMR spectroscopy.

Abstract 2823: Low merlin level as a biomarker for sensitivity of ovarian cancer cell lines to FAK inhibition

Abstract Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that undergoes gene amplification in &amp;gt;20% of serous ovarian cancers. In addition to increased tumor growth and spread, ovarian cancer patients with FAK amplification have a poorer prognosis with decreased overall survival. Merlin, a product of the NF2 tumor suppressor gene, is being evaluated as a biomarker for sensitivity to FAK inhibition in human clinical trials for malignant mesothelioma. As it remains undetermined whether linkages exist between merlin and FAK in other tumor types, we evaluated nine human and two murine ovarian cancer cell lines with sub-micromolar levels of FAK inhibitor (PF-271) for effects on anchorage-independent cell growth. Cells were identified as sensitive (OVCAR3, OVCAR8, HEY, ID8-IP), intermediate (A2780, IGROV1), or resistant (OVCAR10, IGROV1-IP, SKOV3, SKOV3-IP, 5009) to FAK inhibition. Notably, merlin protein levels were high in all resistant cell lines, moderate in intermediate cell lines, and low or undetectable in sensitive cell lines. Oral FAK inhibitor administration reduced orthotopic tumor growth of sensitive (ID8-IP, low merlin) but not resistant (5009, high merlin) murine ovarian carcinoma cells. However, stable knockdown of merlin expression in resistant SKOV3-IP and OVCAR10 human ovarian carcinoma cells did not induce sensitivity to FAK inhibition in vitro. These results support the notion that high merlin expression is correlated with a FAK-inhibitor resistant phenotype, likely through an indirect mechanistic linkage. Nevertheless, merlin protein levels may serve as a biomarker to predict ovarian cancer sensitivity or resistance to FAK inhibitor treatment. Supported by NIH CA102310 Citation Format: Nina R. Shah, Isabelle Tancioni, Kristy K. Ward, Christine Lawson, Xiao Lei Chen, Nichol L.G. Miller, Florian J. Sulzmaier, Sean Uryu, David D. Schlaepfer. Low merlin level as a biomarker for sensitivity of ovarian cancer cell lines to FAK inhibition. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2823. doi:10.1158/1538-7445.AM2014-2823

Abstract 1801: APR-246, a clinical-stage mutant p53-reactivating compound, resensitizes ovarian cancer cells to platinum compounds and doxorubicin

Abstract Background: Platinum-based drugs are since decades used as first-line treatment for many solid tumors. Patients with ovarian cancer often respond well to platinum compounds but a majority of patients rapidly develop resistance and die of chemotherapy refractory disease. The mechanisms underlying resistance are multifactorial, but two of the main causes are mutations in the tumor suppressor p53 and elevated intracellular glutathione (GSH) levels. Mutations in p53 occur in about 60% of ovarian tumors. APR-246 (PRIMA-1MET) is the first clinical-stage compound that reactivates mutant p53. APR-246 is a prodrug that accumulates in cancer cells and is converted to the active form MQ, a Michael acceptor that binds to mutant p53, refolds it to wild type conformation and triggers apoptosis (Lambert et al. Cancer Cell 15, 2009). APR-246 has been tested in a Phase I/IIa clinical trial with promising results (Lehmann et al. J Clin Oncol 30, 2012), and a Phase Ib/II study with platinum-based combination therapy in recurrent p53 mutant ovarian cancer is underway. Methods: Cell viability was assessed with WST-1, MTT or FMCA assay. p53 gene status was determined by Sanger sequencing and single strand conformation analysis, and p53 protein expression by Western blotting. Intracellular GSH levels were assessed with GSH kit (Cayman). Results: We have previously shown outstanding synergistic anticancer effects with APR-246 in combination with platinum compounds in p53 mutant solid cancer cell lines, including cisplatin resistant ovarian cancer cells. Synergistic effects were also observed ex vivo as well as in vivo in mice carrying human tumor xenografts. Here we show that APR-246 not only reactivates mutant p53 but also decreases intracellular GSH levels in a dose-dependent manner, presumably via adduct formation between MQ and GSH. APR-246 resensitized cisplatin resistant p53 mutant ovarian A2780-CP20 carcinoma cells to cisplatin, as shown by a decrease in the IC50 value from 52 to 2.9 µM, similar to the IC50 in parental A2780 cells. APR-246 also restored the sensitivity of resistant A2780ADR cells to doxorubicin. A2780-CP20 and A2780ADR were developed from the parental A2780 line with wild type p53 by chronic exposure to the respective drug. Moreover, APR-246 resensitized the p53 mutant OVCAR-3 cell line, established from a drug resistant patient, to cisplatin. Conclusions: Our results show that APR-246 not only reactivates mutant p53 but also decreases intracellular glutathione levels. We propose that this unique dual mechanism of action accounts for the resensitization and strong synergistic effects with APR-246 and platinum drugs. Our results provide strong rationale for the planned clinical study in ovarian cancer and suggest that combination treatment with APR-246 and DNA damaging drugs could have broad applicability in the treatment of drug resistant p53 mutant human tumors. Citation Format: Nina Mohell, Jessica Alfredsson, Åsa Fransson, Vladimir Bykov, Mikael von Euler, Klas Wiman, Ulf Björklund. APR-246, a clinical-stage mutant p53-reactivating compound, resensitizes ovarian cancer cells to platinum compounds and doxorubicin. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1801. doi:10.1158/1538-7445.AM2014-1801

Abstract 3693: Preclinical antitumor activity of SST0116CL1, a novel heat shock protein 90 (HSP90) inhibitor

Abstract Hsp90 is a component of a molecular chaperone complex, involved in the folding, maturation and stabilisation of key signaling molecules which control cell proliferation, survival and transformation. It works by a modulation of a set of cancer-associated proteins, collectively referred to as ‘‘clients’'. Inhibition of Hsp90 causes simultaneous destabilization and eventual degradation of client proteins that result in suppression of tumor growth, and a number of novel synthetic HSP90 inhibitors are currently under oncology clinical investigations for the treatment of a wide variety of tumor types. SST0116CL1 (property of sigma-tau Research Switzerland S.A.) is a potent, second generation, small-molecule HSP90 inhibitor, with a chemical structure (4-amino substituted resorcino-isoxazole) unrelated to the first generation ansamycin family of HSP90 inhibitors. SST0116CL1 binds to the ATP binding pocket of HSP90, and interferes with HSP90 chaperone function thus resulting in client protein degradation and tumor growth inhibition. In in vitro studies, SST0116CL1 was shown to inhibit recombinant HSP90α and to induce the degradation of the oncogenic Her2 tyrosine kinase in BT-474 human breast cancer cells. Moreover, it was able to induce the destabilization and depletion of different client proteins, often overexpressed and constitutively activated in numerous types of hematological or solid human tumors. These results correlated well with those obtained from the cell proliferation assay as well as with the HSP90 competitive binding assay, and clearly suggested that target modulation of HSP90 was achieved. In preclinical in vivo studies, in different solid and hematological tumor xenograft models, such as A431 epidermoid carcinoma with EGFR overexpression, GTL-16 gastric carcinoma with c-Met overexpression, MV4;11 B-myelomonocytic leukemia with flt3 mutation, A2780/Dx multidrug resistant ovarian carcinoma with P-glycoprotein overexpression, SST0116CL1 delivered intravenously or intraperitoneally revealed a potency at least comparable or higher than that found with the HSP90 inhibitor NVP-AUY922, under Phase II clinical trials investigation, or chemotherapeutic drugs currently used in cancer therapy. SST0116CL1 showed to be a manageable compound when given according to different schedules (qd5x/w; q4d/w; q2dx3/w), since it was well-tolerated and active to inhibit the tumor growth. A modulation of PD biomarkers in terms of down-regulation of EGFR, AKT and CDK4 was reached in tumor lesions of A431 tumor bearing mice treated with SST0116CL1 and a down-regulation of c-Met, AKT and CDK4 was observed in tumors collected from GTL-16 tumor bearing mice. PK parameters demonstrated a rapid clearance of SST0116CL1 from normal tissues and a blood compartment with prolonged retention in tumors. On the complex, these results strongly encourage the selection of SST0116CL1 as a promising candidate for clinical trial. Citation Format: Loredana Vesci, Ferdinando Milazzo, Valeria Carollo, Silvia Pace, Giuseppe Giannini. Preclinical antitumor activity of SST0116CL1, a novel heat shock protein 90 (HSP90) inhibitor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3693. doi:10.1158/1538-7445.AM2014-3693

Abstract 752: Genetic and pharmacological FAK inhibition disrupt a β5 integrin signaling axis controlling anchorage-independent ovarian carcinoma growth

Abstract Ovarian cancer spreads via cell shedding and growth within malignant ascites. Effective targeted therapies have not been developed for ovarian cancer. Ascites contains an abundance of matrix proteins, and spheroids maintain integrin receptor expression. Through databases analyses we find that elevated osteopontin (OPN), β5 integrin, and focal adhesion kinase (FAK) mRNA levels are associated with decreased overall survival of serous ovarian cancer patients treated with platinum and taxol. In ovarian tumor tissue arrays, increased FAK activation (FAK Y397 phosphorylation) correlated with elevated tumor grade in parallel with increased in β5 integin and OPN levels. FAK is a cytoplasmic tyrosine kinase that remains active in spheroids, and treatment of seven ovarian carcinoma cell lines with sub-micromolar levels of FAK inhibitor (PND-1186) identified sensitive (HEY and OVCAR8), intermediate (OVCAR3, ID8-IP, and IGROV1-IP), and resistant (SKOV3-IP and OVCAR10) cells to blockage of growth under anchorage-independent conditions. Genetic or pharmacological FAK inhibition within ID8-IP or HEY cells selectively prevents anchorage-independent growth in culture and tumor growth in mice with corresponding reductions in β5 integrin and OPN expression. β5 knockdown reduced HEY growth in soft agar, tumor growth in mice, FAK Y397 phosphorylation, and OPN expression in spheroids. Although FAK inhibitor resistant ovarian carcinoma cells (SKOV3-IP and OVCAR10) were associated with anchorage-independent Akt S473 phosphorylation, membrane-targeted and activated Akt expression in sensitive cells (HEY and OVCAR8) resulted in only a partial rescue of FAK inhibitor-associated growth block. These results support the hypothesis that OPN, αvβ5 integrins, and FAK may function as a signaling axis promoting ovarian tumor progression. Although Akt signaling pathway activation is a common event in serous ovarian cancer, our results suggest that this may not impart complete resistance to FAK inhibitor treatment. Supported by NIH CA102310 Citation Format: Isabelle Tancioni, Sean Uryu, Florian Sulzmaier, Nina Shah, Christine Lawson, Nichol L.G. Miller, Christine Jean, Xiao Lei Chen, Kristy K. Ward, David D. Schlaepfer. Genetic and pharmacological FAK inhibition disrupt a β5 integrin signaling axis controlling anchorage-independent ovarian carcinoma growth. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 752. doi:10.1158/1538-7445.AM2014-752

Differential outcome of MEK1/2 inhibitor-platinum combinations in platinum-sensitive and -resistant ovarian carcinoma cells

Deregulated pro-survival signalling plays a role in ovarian carcinoma drug resistance. Here, we show that cisplatin or oxaliplatin in combination with the MEK1/2 inhibitor CI-1040 resulted in a synergistic effect associated with enhanced apoptotic response in platinum-sensitive cells. The drug combinations were additive in platinum-resistant cells exhibiting increased phospho-ERK1/2, down-regulation of apoptosis-related factors (BAX, PUMA, FOXO1) and of phosphatases inhibiting ERK1/2 (DUSP5, DUSP6). Consistently, FOXO1 knockdown in sensitive cells reduced the efficacy of the combination treatment. Pharmacological targeting of ERK1/2 pathway increases cell sensitivity to platinum compounds by interfering with multiple events, ultimately favouring apoptosis induction in selected molecular backgrounds.

Emodin augments cisplatin cytotoxicity in platinum-resistant ovarian cancer cells via ROS-dependent MRP1 downregulation.

The intracellular level of reactive oxygen species (ROS) is closely associated with chemosensitivity of cancer cells. Overexpression of ATP binding cassette transporter MRP1 is correlated with resistance to platinum drugs. In this study, we tested the hypothesis that emodin, a potent ROS generator, may increase sensitivity of cisplatin-(cDDP-) resistant ovarian carcinoma cells to cDDP cytotoxicity via ROS-mediated suppression of MRP1 expression. Using the isogenic pair of the human ovarian carcinoma cell line COC1 and its cDDP resistant variant COC1/DDP, we found that ROS level in the cDDP-sensitive ovarian cancer cells was significantly higher than that in the cDDP-resistant cells. Emodin enhanced ROS production in COC1/DDP cells and consequently sensitized them to cDDP-induced apoptosis. These effects were reversed by addition of the antioxidant N-acetyl-L-cysteine (NAC). Cotreatment with emodin and cDDP inhibited the tumor growth in vivo by increasing tumor cell apoptosis. The emodin-enhanced cDDP cytotoxicity was attributable to downregulation of multidrug resistance-related protein 1 (MRP1) expression. Together, these results suggest that emodin could act as an adjunct to enhance the anticancer effect of cDDP likely through ROS-related downregulation of MRP1 expression, and may be of therapeutic potential in cDDP-refractory ovarian carcinomas.

Evidence of extended (&gt;7 years) activity of bevacizumab and metronomic cyclophosphamide in a patient with platinum-resistant low-grade serous ovarian carcinoma

A patient with platinum resistant low-grade serous ovarian carcinoma had an objective response to therapy with bevacizumab and evidence of extended activity (>7 years). This case report adds to the growing literature regarding the use of bevacizumab in low-grade serous ovarian carcinoma.

The use of biologic agents and clinical trials may prolong survival for women with primary platinum resistant ovarian carcinoma

Hispanic (8%), Asian (4%), and other races (3%). 29% were from the South, 26% from the Midwest, 25% Northeast, and 21% were from the West. 23% of hospitals were higher volume (N20 cases/year) vs. lower volume hospitals. 1647 (25%) underwent robotic surgery (RS), 820 (12%) laparoscopic (LS), vs. 4093 (62%) had open surgery (OS). The older (N 62 years, median) were more likely to have RS compared to younger (26% vs. 24%, p = 0.02). 29% of Whites had RS compared to only 20% Native Americans, 15% Hispanics, 12% Blacks, and 11% of Asians (p b 0.01). Patients from Midwest, Northeast, South and West had RS in 26%, 26%, 25%, and 23% of cases. Higher volume hospital performed 72% of all surgeries and 84% of all RS. Moreover, these higher volume hospitals were more likely to use RS compared to lower volume institutions (29% vs. 14%, p b 0.01). Those with low(b$40,999),middle ($41,000–$50,999), upper middle ($51,000–$66,999), and high (N$67,000) socioeconomic had RS in 21%, 25%, 28%, and 27% of cases (p b 0.01). Those with Medicare orprivate insurance were more likelyto receive RS at 27% and 26% vs. 14% of Medicaid patients (p b 0.01). Conclusions: In this nationwide analysis of endometrial cancer patients, older, Whites, higher socioeconomic class, receiving care from higher volume hospitals were associated with likelihood of receiving robotic surgery. Further studies are warranted to better understand the barriers of receiving robotic surgery.

A phase II study of combination chemotherapy using docetaxel and irinotecan for TC-refractory or TC-resistant ovarian carcinomas (GOGO-OV2 study) and for primary clear or mucinous ovarian carcinomas (GOGO-OV3 Study)

ObjectiveTo analyze the efficacy and safety of combination chemotherapy of docetaxel and irinotecan for paclitaxel and carboplatin (TC) -refractory or -resistant ovarian carcinomas and for first treatment of primary clear cell and mucinous ovarian carcinomas. Study designBetween 2002 and 2009, we conducted a prospective Phase II study of the efficacy and safety of combination chemotherapy using docetaxel and irinotecan in 62 patients with TC-refractory or -resistant ovarian carcinoma cases (GOGO-OV2) and 15 patients with primary clear cell and mucinous ovarian carcinoma cases (GOGO-OV3). The dose of docetaxel and irinotecan was determined during our previous Phase I study. ResultsA docetaxel plus irinotecan regimen provided a 53% response rate, 6 months progression-free survival (PFS), and 12 months overall survival (OS) for primary clear cell and mucinous ovarian carcinomas (similar to TC therapy). The differences of anti-tumor and survival effects between refractory and resistant cases were not statistically significant. The regimen also provided a 15% response rate, 5 months PFS, and 15 months OS for TC-refractory or TC-resistant cases, when used as a second-line chemotherapy. These data are similar to previous reports, however, our study provides the first data exclusively for the cases refractory or resistant to a gold standard TC therapy as a second-line chemotherapy. The regimen was demonstrated to be well tolerable. ConclusionCombination chemotherapy of docetaxel and irinotecan may be a useful option to treat TC-refractory/resistant cases and primary clear cell and mucinous adenocarcinoma cases of ovarian carcinoma.