6mer Seed Toxicity and Platinum Resistance in Ovarian Cancer

ABSTRACTDevelopment of platinum (Pt) resistance is a major barrier to curing ovarian cancer (OC). 6mer seed toxicity is a novel cancer killing mechanism mediated by tumor suppressive miRNAs with a toxic 6mer seed sequence (positions 2-7) through the RNA-induced silencing complex (RISC). The most toxic 6mer seeds are G-rich and kill cells by targeting the 3′ untranslated region of genes critical for cell survival. We now show that treatment of OC cells with Pt leads to an increase in RISC-bound miRNAs carrying toxic 6mer seeds and a decrease in miRNAs with nontoxic seeds. Pt-resistant cells did not exhibit this Pt induced toxicity shift but retained sensitivity to death mediated by siRNAs carrying toxic 6mer seeds. Analysis of RISC-bound miRNAs in OC patients revealed that miRNA 6mer seed toxicity ratios were predictive of treatment outcomes. Our results suggest that 6mer seed toxicity can be exploited to treat patients with Pt-resistant OC.

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Treatment of chemoresistant ovarian cancer with sigma2/SMAC and cisplatin.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.e16508 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. e16508-e16508

Author(s):

Ivy Wilkinson-Ryan ◽

Dirk Spitzer ◽

Robert Mach ◽

Suwanna Vangveravong ◽

Peter S Goedegebuure ◽

...

Keyword(s):

Ovarian Cancer ◽

Combination Therapy ◽

Cancer Cells ◽

Caspase 3 ◽

Platinum Resistance ◽

Apoptotic Pathway ◽

Major Barrier ◽

Skov3 Cells

e16508 Background: Platinum resistance continues to be a major barrier to the successful treatment of ovarian cancer. Overexpression of the X-linked inhibitor of apoptosis proteins (XIAP) contribute to platinum resistance in ovarian cancer through inhibition of caspases and up regulation of Akt activity. Second mitochondrial-derived activators of caspases (SMAC) is an endogenous protein that binds to and reverses XIAP-mediated inhibition of caspases. In order to exploit the SMAC-mediated pro-apoptotic pathway pharmacologically, SMAC mimetics have been developed and shown to induce apoptosis in cancer cells in vitro and in vivo. Untargeted cytotoxic cancer drugs bind to both malignant and normal tissue leading to significant toxicity. We have shown previously that solid tumors upregulate the sigma-2 receptor. We have also shown that sigma-2 ligands are internalized into cancer cells and are therefore an appealing vehicle for tumor targeted therapy. The goal of this study is to test if a conjugate drug of sigma-2 ligand and a SMAC mimetic (sigma-2/SMAC) in combination with chemotherapy is capable of overcoming chemoresistance in ovarian cancer. Methods: SKOV3 and OVCAR3 ovarian cancer cell lines were treated with sigma2/SMAC (1-16μM) and/or cisplatin (.5-10μg/mL). Viability assays were used to detect cell death. Luminescence-based caspase assays were used to compare the activity of caspase-3, -7, and -9 between treatment groups to document involvement of the XIAP survival pathway. Results: We found that sigma2-SMAC is synergistic when used in combination with cisplatin. Compared to untreated cells, SKOV3 cells treated with sigma/2SMAC (4uM), cisplatin .5ug/mL, or combination therapy showed 52.6%, 117.7%, and 34.8% viability respectively (p<.05). Cisplatin and sigma2/SMAC remained synergistic at increasing doses. Similar results were observed in OVCAR3 cells. Caspase-3 and -7 increased in combination therapy 1.2-fold over Sigma/2SMAC alone (4uM) and 7-fold over cisplatin alone (.5ug/mL) in SKOV3 cells (p<.05). Conclusions: This study suggests that the sigma2/SMAC conjugate provides a targeted means for overcoming chemoresistance in ovarian cancer through inhibition of XIAP and activation of caspases.

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Co-targeting EGFR and Autophagy Impairs Ovarian Cancer Cell Survival during Detachment from the ECM

Current Cancer Drug Targets ◽

10.2174/1568009615666150126161939 ◽

2015 ◽

Vol 15 (3) ◽

pp. 215-226 ◽

Cited By ~ 9

Author(s):

Zongyuan Yang ◽

Yi Liu ◽

Xiao Wei ◽

Xiaoshui Zhou ◽

Cheng Gong ◽

...

Keyword(s):

Ovarian Cancer ◽

Cell Survival ◽

Cancer Cell ◽

Ovarian Cancer Cell ◽

Cancer Cell Survival

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The BRCA2 p.N372 H i.a.1342A>C Could Regulate the Sensitivity of Ovarian Cancer Cells to Platinum-Based Drugs

Technology in Cancer Research & Treatment ◽

10.1177/1533033820983289 ◽

2020 ◽

Vol 19 ◽

pp. 153303382098328

Author(s):

Zhen-Hua Du ◽

Yu Xia ◽

Qing Yang ◽

Song Gao

Keyword(s):

Ovarian Cancer ◽

Cancer Cells ◽

Mutant Gene ◽

Negative Control ◽

Ovarian Cancer Cells ◽

Platinum Resistance ◽

Over Expression ◽

Ic50 Value ◽

Brca2 Protein ◽

Recombination Repair

Background and Objective: We have previously reported that BRCA2 N372 H i.a.1342A>C heterozygous variation presented in platinum-resistant patients. This study aimed to further investigate the mechanism of BRCA2 N372 H mutation in the development of platinum resistance in ovarian cancer. Methods: The BRCA2 N372 H i.a.1342A>C was synthesized and used to exchange 1 wildtype allele followed by sequencing to confirm the mutant allele sequence. Plasmids were constructed and transfected into the OVCAR-3 cells after lentiviral packaging. BRCA2 N372 H mRNA was detected by qPCR. BRCA2 protein was assessed by immunoblotting. Binding of the BRCA2 to Rad51 was detected by immunofluorescence staining. Sensitivity of the cells to cisplatin treatment was assessed with CCK-8 assay. Results: It was found that expression of BRCA2 protein in ovarian cancer cells transfected with BRCA2 N372 H i.a.1342A>C gene (2.177 ± 0.003) was significantly increased compared to that of the cells transfected with lenti-EGFP only (1.227 ± 0.003, P < 0.001). Binding of the BRCA2 and Rad51 proteins was significantly increased in the cells with BRCA2 N372 H i.a.1342A>C mutation (3.542 ± 0.24) than that in the cells transfected with lenti-EGFP (1.29 ± 0.32) or empty cells (1.363 ± 0.32, P < 0.001). Cell viability significantly increased in the cells transfected with BRCA2 N372 H mutant gene. The IC50 value was significantly higher in the cells transfected with BRCA2 N372 H mutant gene (1.963 ± 0.04) than that of the cells transfected with lenti-EGFP (0.955 ± 0.03, P < 0.01) or empty cells (1.043 ± 0.007, P < 0.01). Conclusion: Over expression of mRNA and protein of BRCA2 was detected in the cells with BRCA2 N372 H i.a.1342A>C mutation but not in the lentivirus negative control (lenti-EGFP) or the cells without transfection (empty cells), which may lead to resistance to platinum-based drugs in ovarian cancer cells through homologous recombination repair pathway.

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Emerging Roles for Ion Channels in Ovarian Cancer: Pathomechanisms and Pharmacological Treatment

Cancers ◽

10.3390/cancers13040668 ◽

2021 ◽

Vol 13 (4) ◽

pp. 668

Author(s):

Concetta Altamura ◽

Maria Raffaella Greco ◽

Maria Rosaria Carratù ◽

Rosa Angela Cardone ◽

Jean-François Desaphy

Keyword(s):

Ovarian Cancer ◽

Ion Channels ◽

Transient Receptor Potential ◽

Critical Role ◽

Gynecologic Cancer ◽

Receptor Potential ◽

Transient Receptor Potential Channels ◽

Platinum Resistance

Ovarian cancer (OC) is the deadliest gynecologic cancer, due to late diagnosis, development of platinum resistance, and inadequate alternative therapy. It has been demonstrated that membrane ion channels play important roles in cancer processes, including cell proliferation, apoptosis, motility, and invasion. Here, we review the contribution of ion channels in the development and progression of OC, evaluating their potential in clinical management. Increased expression of voltage-gated and epithelial sodium channels has been detected in OC cells and tissues and shown to be involved in cancer proliferation and invasion. Potassium and calcium channels have been found to play a critical role in the control of cell cycle and in the resistance to apoptosis, promoting tumor growth and recurrence. Overexpression of chloride and transient receptor potential channels was found both in vitro and in vivo, supporting their contribution to OC. Furthermore, ion channels have been shown to influence the sensitivity of OC cells to neoplastic drugs, suggesting a critical role in chemotherapy resistance. The study of ion channels expression and function in OC can improve our understanding of pathophysiology and pave the way for identifying ion channels as potential targets for tumor diagnosis and treatment.

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Evaluating Targeted Therapies in Ovarian Cancer Metabolism: Novel Role for PCSK9 and Second Generation mTOR Inhibitors

Cancers ◽

10.3390/cancers13153727 ◽

2021 ◽

Vol 13 (15) ◽

pp. 3727

Author(s):

Dafne Jacome Sanz ◽

Juuli Raivola ◽

Hanna Karvonen ◽

Mariliina Arjama ◽

Harlan Barker ◽

...

Keyword(s):

Ovarian Cancer ◽

Lipid Metabolism ◽

Cell Survival ◽

Drug Testing ◽

Cancer Metabolism ◽

Ex Vivo ◽

Specific Inhibitor ◽

Low Grade ◽

Serous Ovarian Cancer

Background: Dysregulated lipid metabolism is emerging as a hallmark in several malignancies, including ovarian cancer (OC). Specifically, metastatic OC is highly dependent on lipid-rich omentum. We aimed to investigate the therapeutic value of targeting lipid metabolism in OC. For this purpose, we studied the role of PCSK9, a cholesterol-regulating enzyme, in OC cell survival and its downstream signaling. We also investigated the cytotoxic efficacy of a small library of metabolic (n = 11) and mTOR (n = 10) inhibitors using OC cell lines (n = 8) and ex vivo patient-derived cell cultures (PDCs, n = 5) to identify clinically suitable drug vulnerabilities. Targeting PCSK9 expression with siRNA or PCSK9 specific inhibitor (PF-06446846) impaired OC cell survival. In addition, overexpression of PCSK9 induced robust AKT phosphorylation along with increased expression of ERK1/2 and MEK1/2, suggesting a pro-survival role of PCSK9 in OC cells. Moreover, our drug testing revealed marked differences in cytotoxic responses to drugs targeting metabolic pathways of high-grade serous ovarian cancer (HGSOC) and low-grade serous ovarian cancer (LGSOC) PDCs. Our results show that targeting PCSK9 expression could impair OC cell survival, which warrants further investigation to address the dependency of this cancer on lipogenesis and omental metastasis. Moreover, the differences in metabolic gene expression and drug responses of OC PDCs indicate the existence of a metabolic heterogeneity within OC subtypes, which should be further explored for therapeutic improvements.

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SENP1-mediated deSUMOylation of JAK2 regulates its kinase activity and platinum drug resistance

Cell Death and Disease ◽

10.1038/s41419-021-03635-6 ◽

2021 ◽

Vol 12 (4) ◽

Author(s):

Jing Li ◽

Ruiqin Wu ◽

Mingo M. H. Yung ◽

Jing Sun ◽

Zhuqing Li ◽

...

Keyword(s):

Ovarian Cancer ◽

Drug Resistance ◽

Kinase Activity ◽

Regulatory Mechanism ◽

Platinum Resistance ◽

Platinum Drug ◽

Clinical Prognosis ◽

Platinum Resistant ◽

Poor Clinical Prognosis ◽

Stat Pathway

AbstractThe JAK2/STAT pathway is hyperactivated in many cancers, and such hyperactivation is associated with a poor clinical prognosis and drug resistance. The mechanism regulating JAK2 activity is complex. Although translocation of JAK2 between nucleus and cytoplasm is an important regulatory mechanism, how JAK2 translocation is regulated and what is the physiological function of this translocation remain largely unknown. Here, we found that protease SENP1 directly interacts with and deSUMOylates JAK2, and the deSUMOylation of JAK2 leads to its accumulation at cytoplasm, where JAK2 is activated. Significantly, this novel SENP1/JAK2 axis is activated in platinum-resistant ovarian cancer in a manner dependent on a transcription factor RUNX2 and activated RUNX2/SENP1/JAK2 is critical for platinum-resistance in ovarian cancer. To explore the application of anti-SENP1/JAK2 for treatment of platinum-resistant ovarian cancer, we found SENP1 deficiency or treatment by SENP1 inhibitor Momordin Ic significantly overcomes platinum-resistance of ovarian cancer. Thus, this study not only identifies a novel mechanism regulating JAK2 activity, but also provides with a potential approach to treat platinum-resistant ovarian cancer by targeting SENP1/JAK2 pathway.

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Hypermethylation of mismatch repair gene hMSH2 associates with platinum-resistant disease in epithelial ovarian cancer

Clinical Epigenetics ◽

10.1186/s13148-019-0748-4 ◽

2019 ◽

Vol 11 (1) ◽

Cited By ~ 3

Author(s):

Hua Tian ◽

Li Yan ◽

Li Xiao-fei ◽

Sun Hai-yan ◽

Chen Juan ◽

...

Keyword(s):

Mass Spectrometry ◽

Ovarian Cancer ◽

Dna Methylation ◽

Epithelial Ovarian Cancer ◽

Upstream Region ◽

Platinum Resistance ◽

Maldi Tof Mass Spectrometry ◽

Platinum Resistant ◽

Aberrant Dna Methylation ◽

Low Expression

Abstract Purpose One major reason of the high mortality of epithelial ovarian cancer (EOC) is due to platinum-based chemotherapy resistance. Aberrant DNA methylation may be a potential mechanism underlying the development of platinum resistance in EOC. The purpose of this study is to discover potential aberrant DNA methylation that contributes to drug resistance. Methods By initially screening of 16 platinum-sensitive/resistant samples from EOC patients with reduced representation bisulfite sequencing (RRBS), the upstream region of the hMSH2 gene was discovered hypermethylated in the platinum-resistant group. The effect of hMSH2 methylation on the cellular response to cisplatin was explored by demethylation and knockdown assays in ovarian cancer cell line A2780. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry was employed to examine the methylation levels of hMSH2 upstream region in additional 40 EOC patient samples. RT-qPCR and IHC assay was used to detect the hMSH2 mRNA and protein expression in extended 150 patients. Results RRBS assay discovered an upstream region from − 1193 to − 1125 of hMSH2 was significant hypermethylated in resistant EOC patients (P = 1.06 × 10−14). In vitro analysis demonstrated that global demethylation increased cisplatin sensitivity along with a higher expression of the hMSH2 mRNA and protein. Knockdown hMSH2 reduced the cell sensitivity to cisplatin. MALDI-TOF mass spectrometry assay validated the strong association of hypermethylation of hMSH2 upstream region with platinum resistance. Spearman’s correlation analysis revealed a significantly negative connection between methylation level of hMSH2 upstream region and its expression. The Kaplan-Meier analyses showed the high methylation of hMSH2 promoter region, and its low expressions are associated with worse survival. In multivariable models, hMSH2 low expression was an independent factor predicting poor outcome (P = 0.03, HR = 1.91, 95%CI = 1.85–2.31). Conclusion The hypermethylation of hMSH2 upstream region is associated with platinum resistant in EOC, and low expression of hMSH2 may be an index for the poor prognosis.

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Oncogenic Role of miR-200c-3p in High-Grade Serous Ovarian Cancer Progression via Targeting the 3′-Untranslated Region of DLC1

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18115741 ◽

2021 ◽

Vol 18 (11) ◽

pp. 5741

Author(s):

Sheril June Ankasha ◽

Mohamad Nasir Shafiee ◽

Norhazlina Abdul Wahab ◽

Raja Affendi Raja Ali ◽

Norfilza Mohd Mokhtar

Keyword(s):

Ovarian Cancer ◽

Cancer Progression ◽

Untranslated Region ◽

Luciferase Reporter ◽

Clinical Samples ◽

Binding Motif ◽

Skov3 Cell ◽

High Grade ◽

Serous Ovarian Cancer ◽

Dlc1 Expression

High-grade serous ovarian cancer (HGSC) is the most common ovarian cancer with highly metastatic properties. A small non-coding RNA, microRNA (miRNA) was discovered to be a major regulator in many types of cancers through binding at the 3′-untranslated region (3′UTR), leading to degradation of the mRNA. In this study, we sought to investigate the underlying mechanisms involved in the dysregulation of miR-200c-3p in HGSC progression and metastasis. We identified the upregulation of miR-200c-3p expression in different stages of HGSC clinical samples and the downregulation of the tumor suppressor gene, Deleted in Liver Cancer 1 (DLC1), expression. Over expression of miR-200c-3p in HGSC cell lines downregulated DLC1 but upregulated the epithelial marker, E-cadherin (CDH1). Based on in silico analysis, two putative binding sites were found within the 3′UTR of DLC1, and we confirmed the direct binding of miR-200c-3p to the target binding motif at position 1488–1495 bp of 3′UTR of DLC1 by luciferase reporter assay in a SKOV3 cell line co-transfected with vectors and miR-200c-3p mimic. These data showed that miR-200c-3p regulated the progression of HGSC by regulating DLC1 expression post-transcription and can be considered as a promising target for therapeutic purposes.

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