Cisplatin In Ovarian Cancer Cells Research Articles

Antitumor effects of redox-responsive nanoparticles containing platinum（Ⅳ）in ovarian cancer

Objectives: To explore the antitumor effects of redox-responsive nanoparticles containing platinum(Ⅳ)-NP@Pt(Ⅳ) in ovarian cancer. Methods: Redox-responsive polymer carriers were synthesized. Polymer carriers and platinum(Ⅳ)-Pt(Ⅳ) can self-assemble into NP@Pt(Ⅳ). Inductively coupled plasma mass spectrometry was performed to detect the platinum release from NP@Pt(Ⅳ) in reducing environment and the platinum content in ovarian cancer cells ES2 treated with cisplatin, Pt(Ⅳ) and NP@Pt(Ⅳ). The proliferation ability of the ovarian cancer cells were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cellular apoptosis was assessed by flow cytometry. Collection of primary ovarian cancer tissues from patients with primary high-grade serous ovarian cancer who were surgically treated at the Cancer Hospital of the Chinese Academy of Medical Sciences from October to December 2022. The high-grade serous ovarian cancer patient-derived xenograft (PDX) mice were intravenously injected with Cy7.5 labeled NP@Pt(Ⅳ) followed by in vivo imaging system. Mice were treated with PBS, cisplatin and NP@Pt(Ⅳ). Tumor volume and weight were measured in each group. Necrosis, apoptosis and cell proliferation of tumor tissues were detected by hematoxylin-eosin (HE) staining, TUNEL fluorescence staining and Ki-67 immunohistochemistry staining. Body weight and HE staining of heart, liver, spleen, lung and kidney of mice in each group were measured. Results: The platinum release of NP@Pt(Ⅳ) after 48 hours in reducing environment was 76.29%, which was significantly higher than that of 26.82% in non-reducing environment (P<0.001). The platinum content in ES2 cells after 4 hours and 7 hours of treatment with NP@Pt(Ⅳ) (308.59, 553.15 ng/million cells) were significantly higher than those of Pt(Ⅳ) (100.21, 180.31 ng/million cells) and cisplatin (43.36, 50.36 ng/million cells, P＜0.05). The half inhibitory concentrations of NP@Pt(Ⅳ) in ovarian cancer cells ES2, A2780, A2780DDP were 1.39, 1.42 and 4.62 μmol/L, respectively, which were lower than those of Pt(IV) (2.89, 7.27, and 16.74 μmol/L) and cisplatin (5.21, 11.85, and 71.98 μmol/L). The apoptosis rate of ES2 cells treated with NP@Pt(Ⅳ) was (33.91±3.80)%, which was significantly higher than that of Pt(Ⅳ) [(16.28±2.41)%] and cisplatin [(15.01±1.17)%, P＜0.05]. In high-grade serous ovarian cancer PDX model, targeted accumulation of Cy7.5 labeled NP@Pt(Ⅳ) at tumor tissue could be observed. After the treatment, the tumor volume of mice in NP@Pt(IV) group was (130±98) mm3, which was significantly lower than those in control group [(1 349±161) mm3, P<0.001] and cisplatin group [(715±293) mm3, P=0.026]. The tumor weight of mice in NP@Pt(IV) group was (0.17±0.09)g, which was significantly lower than those in control group [(1.55±0.11)g, P<0.001] and cisplatin group [(0.82±0.38)g, P=0.029]. The areas of tumor necrosis and apoptosis in mice treated with NP@Pt(Ⅳ) were higher than those in mice treated with cisplatin. Immunohistochemical staining revealed that there were low expressions of Ki-67 at tumor tissues of mice treated with NP@Pt(Ⅳ) compared with cisplatin. The change in body weight of mice in NP@Pt(Ⅳ) group was not significantly different from that of the control group [(18.56±2.04)g vs.(20.87±0.79)g, P=0.063]. Moreover, the major organs of the heart, liver, spleen, lung, and kidney were also normal by HE staining. Conclusion: Redox-responsive NP@Pt(Ⅳ), produced in this study can enhance the accumulation of cisplatin in ovarian cancer cells and improve the efficacy of ovarian cancer chemotherapy.

The splicing factor SNRPB promotes ovarian cancer progression through regulating aberrant exon skipping of POLA1 and BRCA2.

Splicing factors play a crucial role in the initiation and development of various human cancers. SNRPB, a core spliceosome component, regulates pre-mRNA alternative splicing. However, its function and underlying mechanism in ovarian cancer remain unclear. This study identified SNRPB as a critical driver of ovarian cancer through TCGA and CPTAC database analysis. SNRPB was highly upregulated in fresh frozen ovarian cancer tissues compared with normal fallopian tubes. Immunohistochemistry revealed that SNRPB expression was increased in formalin-fixed, paraffin-embedded ovarian cancer sections and was positively correlated with a poor prognosis for ovarian cancer. Functionally, SNRPB knockdown suppressed ovarian cancer cell proliferation and invasion, and overexpression exerted opposite effects. SNRPB expression increased after cisplatin treatment, and silencing SNRPB sensitized ovarian cancer cells to cisplatin. KEGG pathway analysis revealed that the differentially expressed genes (DEGs) were mainly enriched in DNA replication and homologous recombination, and almost all DEGs related to DNA replication and homologous recombination were downregulated after SNRPB knockdown according to RNA-seq. Exon 3 skipping of the DEGs DNA polymerase alpha 1 (POLA1) and BRCA2 was induced by SNRPB silencing. Exon 3 skipping of POLA1 yielded premature termination codons and led to nonsense-mediated RNA decay (NMD); exon 3 skipping of BRCA2 led to loss of the PALB2 binding domain, which is necessary for homologous recombination, and increased ovarian cancer cell cisplatin sensitivity. POLA1 or BRCA2 knockdown partially impaired the increased malignancy of SNRPB-overexpressing ovarian cancer cells. Moreover, miR-654-5p was found to reduce SNRPB mRNA expression by directly binding to the SNRPB 3'-UTR. Overall, SNRPB was identified as an important oncogenic driver that promotes ovarian cancer progression by repressing exon 3 skipping of POLA1 and BRCA2. Thus, SNRPB is a potential treatment target and prognostic marker for ovarian cancer.

Baohuoside I inhibits resistance to cisplatin in ovarian cancer cells by suppressing autophagy via downregulating HIF-1α/ATG5 axis.

Since chemotherapy's therapeutic impact is diminished by drug resistance, treating ovarian cancer is notably challenging. Thereafter, it is critical to develop cutting-edge approaches to treating ovarian cancer. Baohuoside I (derived from Herba Epimedii) is reported to have antitumor properties in various malignancies. It is unknown, however, what role Baohuoside I plays in cisplatin (DDP)-resistant ovarian cancer cells.3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT), colony formation, and flow cytometry assay were used to investigate the impact of Baohuoside I on ovarian cancer A2780 cells and DDP-resistant A2780 (A2780/DDP) cells. The level of microtubule associated protein 1 light chain 3 (LC3) was determined using immunofluorescence staining. Utilizing the mRFP-GFP-LC3B tandem fluorescent probe allowed us to analyse the autophagy flux. Analysis of mRNA and protein level was performed using RT-qPCR and Western blot analysis, respectively. The interaction between hypoxia inducible factor 1 subunit alpha (HIF-1α) and autophagy related 5 (ATG5) promoter was investigated by dual luciferase and ChIP assay. Additionally, evaluation of Baohuoside I's role in ovarian cancer was performed using a nude mouse xenograft model.Baohuoside I decreased the viability and proliferation and triggered the apoptosis of both A2780 and A2780/DDP cells in a concentration-dependent manner. Baohuoside I also increased the sensitivity of A2780/DDP cells to DDP. Concurrently, HIF-1α could promote A2780/DDP cells resistance to DDP. In addition, HIF-1α could induce the autophagy of A2780/DDP cells through transcriptionally activating ATG5, and Baohuoside I imporved the chemosensitivity of A2780/DDP cells to DDP by downregulating HIF-1α. Moreover, Baohuoside I could inhibit the chemoresistance to DDP in ovarian cancer in vivo.Baohuoside I sensitizes ovarian cancer cells to DDP by suppressing autophagy via downregulating the HIF-1α/ATG5 axis. Consequently, Baohuoside I might be evaluated as a new agent for enhancing the chemotherapeutic efficacy of drug treatment for ovarian cancer.

Circ_0078607 increases platinum drug sensitivity via miR-196b-5p/GAS7 axis in ovarian cancer

ABSTRACT Platinum-based chemotherapy is one of the predominant strategies for treating ovarian cancer (OC), however, platinum resistance greatly influences the therapeutic effect. Circular RNAs (circRNAs) have been found to participate in the pathogenesis of platinum resistance. Our aim was to explore the involvement of circ_0078607 in OC cell cisplatin (DDP) resistance and its potential mechanisms. Circ_0078607, miR-196b-5p, and growth arrest-specific 7 (GAS7) levels were assessed by qPCR. Circ_0078607 stability was assessed by ribonuclease R digestion and actinomycin D treatment. Cell viability of various conic of DDP treatment was measured by CCK-8. The cell proliferation was determined by CCK-8 and colony formation assay. Western blotting was performed for determining GAS7, ABCB1, CyclinD1 and Bcl-2 protein levels. The direct binding between miR-196b-5p and circ_0078607 or GAS7 was validated by dual-luciferase reporter and RIP assay. DDP resistance in vivo was evaluated in nude mice. Immunohistochemistry staining for detecting Ki67 expression in xenograft tumours. Circ_0078607 and GAS7 was down-regulated, but miR-196b-5p was up-regulated in OC samples and DDP-resistant cells. Overexpression of circ_0078607 inhibited DDP resistance, cell growth and induced apoptosis in DDP-resistant OC cells. Mechanistically, circ_0078607 sequestered miR-196b-5p to up-regulate GAS7. MiR-196b-5p mimics reversed circ_0078607 or GAS7 overexpression-mediated enhanced sensitivity. Finally, circ_0078607 improved the sensitivity of DDP in vivo. Circ_0078607 attenuates DDP resistance via miR-196b-5p/GAS7 axis, which highlights the therapeutic potential of circ_0078607 to counter DDP resistance in OC.

Molecular mechanism of CD163+ tumor-associated macrophage (TAM)-derived exosome-induced cisplatin resistance in ovarian cancer ascites

BackgroundStudies have found that tumor-associated macrophages (TAMs) in the malignant ascites of patients with serous ovarian cancer exhibit a mixed polarization phenotype and highly variable expression of the surface marker CD163. The exosomes secreted by mesenchymal cells can be taken up by tumor cells, affecting the malignant biological behavior of them.MethodsUsing reverse transcription-polymerase chain reaction (RT-PCR) to detect the genes expression of drug resistance related factors cancer stem cells (CSCs)/multidrug resistance (MDR)/epithelial-mesenchymal transition (EMT) after CD163+ TAMs exosomes in ovarian cancer ascites co-cultured with A2780 and A2780/cis-diamminedichloroplatinum (DDP). Differences of the level of miR-221-3p expression between CD163+ TAMs cells (M2) and peripheral blood mononuclear cells M0 detect by microarray screening, and bioinformatics analysis predicts that its target gene is ADAMTS6. Western blot (WB) and immunohistochemical detection of ADAMTS6 expression level in epithelial ovarian cancer (EOC) clinical sample tissues, and analysis of the ADAMTS6 expression in ovarian cancer tissues and its correlation with clinicopathological factors. WB was used to detect the expression of AKT pathway and downstream EMT-related molecules [SNAIL1, ZEB1, Vimentin (VIM)] after co-culture of CD163+ TAMs exosomes with ovarian cancer cell lines A2780, A2780/DDP. WB detects the expression of EGFR and TGF-β1 upstream molecules of the AKT signaling pathway (AKT-pAKT) and downstream EMT molecules (SNAIL1, ZEB1, VIM) after overexpression of ADAMTS6 in A2780 and A2780/DDP.ResultsWe demonstrated that after CD163+ TAM exosomes were taken up by EOC cells, the highly expressed miR-221-3p could downregulate the level of ADAMTS6, further activate the AKT signaling pathway, and increase the expression of EMT transcription factors SNAIL1 and ZEB1 and the mesothelial marker VIM. Decreased expression of the epithelial marker E-cadherin induced EMT, triggering a switch to a CSC-like phenotype and MDR, thereby promoting EOC cell proliferation, adhesion, migration, and resistance. Compared with benign ovarian tumors, ADAMTS6 expression was low in EOC tissues and was closely related to the clinical stage, age, and survival curve of ovarian cancer patients.ConclusionsOverexpression of ADAMTS6 reduced the IC50 of cisplatin in ovarian cancer cells. The mechanism may be related to the inhibition of EMT mediated by the EGFR/TGF-β/AKT pathway of EOC cells, which has potential value in the treatment of ovarian cancer.

The cyclin-dependent kinase inhibitor AT7519 augments cisplatin's efficacy in ovarian cancer via multiple oncogenic signaling pathways.

Although cisplatin is the most active drug for the treatment of ovarian cancer, majority of patients develop resistance and ultimately relapse. Enhancing the efficacy of cisplatin could represent a promising strategy to improve the clinical outcome of patients with ovarian cancer. AT7519 is a multitargeted cyclin-dependent kinase (CDK) inhibitor and displays potent anticancer activities. In this work, we show that the combination of AT7519 with cisplatin is much more superior to cisplatin alone in inhibiting ovarian cancer. AT7519 at nanomolar concentrations inhibits proliferation and migration and induces apoptosis of multiple ovarian cancer cell lines. In contrast, AT7519 at the same concentrations either does not affect survival or is significantly less effective in inhibiting proliferation and migration in normal ovarian cells and fibroblast cells. AT7519 significantly augments the inhibitory effects of cisplatin in ovarian cancer cells in a dose-dependent manner. Mechanistic studies suggest that AT7519 (i) inhibits proliferation via decreasing activities of CDK1 and 2, and via inhibiting RNA transcription; (ii) inhibits migration via suppressing epithelial-mesenchymal transition (EMT); and (iii) induces apoptosis via decreasing Mcl-1 and increasing Bim in ovarian cancer cells. Using a human ovarian cancer xenograft mouse model, we confirm the in vivo efficacy of AT7519 alone, and the synergistic effects of AT7519 and cisplatin in combination, at doses that cause minimal toxicity in mice. Our findings provide systematic preclinical evidence to support the initialization of clinical trials of the AT7519 and cisplatin combination for the treatment of ovarian cancer.

Enhanced Accumulation of Cisplatin in Ovarian Cancer Cells from Combination with Wedelolactone and Resulting Inhibition of Multiple Epigenetic Drivers.

PurposeCisplatin resistance is a major concern in ovarian cancer treatment. The aim of this study was to investigate if wedelolactone could perform better in resistant ovarian cancer cells when used in combination with cisplatin.MethodsGrowth inhibitory potential of wedelolactone and cisplatin was investigated through MTT reduction assay in ovarian cancer cell lines including A2780 (sensitive), A2780cisR (cisplatin resistant) and A2780ZD0473R. Resistance factor (RF) of drugs was determined in these three cell lines. Combination index (CI) was calculated as a measure of combined drug action. Effect of this combination on changes in the cellular accumulation of platinum levels and platinum-DNA binding was also determined in vitro using AutoDock Vina while the effect of wedelolactone on inhibition of possible key culprits of resistance including Chk1, CD73, AT tip60, Nrf2, Brd1, PCAF, IGF1, mTOR1 and HIF2α was investigated in silico.ResultsCisplatin and wedelolactone showed a dose-dependent growth inhibitory effect. RF value of wedelolactone was 1.1 in the case of A2780cisR showing its potential to bring more cell death in cisplatin-resistant cells. CI values were found to vary showing antagonistic to additive outcomes. Additive effect was observed for all sequences of administration (0/0, 0/4 and 4/0 h) in A2780cisR. Enhanced cellular accumulation of cisplatin was observed in parent and resistant cells on combination. Docking results revealed that among the selected oncotargets, Chk1, CD73, Nrf2, PCAF and AT tip60 were more vulnerable to wedelolactone than their respective standard inhibitors.ConclusionThese findings have shown that additive outcome of drug combination in A2780cisR and raised levels of platinum accumulation followed a clear pattern. This observation indicates that the presence of wedelolactone might have contributed to sensitize A2780cisR. However, in silico results point to the possible effects of this compound on epigenetic factors involving tumor microenvironment, epithelial mesenchymal transition, and immune-checkpoint kinases.

Oleuropein reduces cisplatin resistance in ovarian cancer by targeting apoptotic pathway regulators

AimsDespite many attempts to treat ovarian cancer, 13,940 individuals perish annually due to this disease worldwide. Chemotherapy is the main approach to ovarian cancer treatment, but the development of drug resistance is a major obstacle to the successful treatment. Oleuropein is a phenolic ingredient with anticancer characteristics. This study was aimed at investigating the effect of oleuropein on cell viability, cisplatin resistance, and apoptosis, as well as the expression levels of miR-34a, miR-125b, miR16, miR-21, and some of their potential target genes in ovarian cancer cells. Main methodsA2780S and A2780/CP cell lines were exposed to different concentrations of oleuropein alone or in combination with cisplatin for 48 h and 72 h. After that, the cell viability and apoptosis were evaluated using MTT assay and flow cytometry, respectively. Bioinformatics analyses were conducted using STRING database and Cytoscape software. The effect of oleuropein and/or cisplatin on the expression of miRNAs and target genes was assessed via Real-time PCR. Key findingsUpon treatment with oleuropein, the expression of P21, P53, and TNFRSF10B increased while that of Bcl-2 and Mcl1 decreased. Moreover, this is the 1st report of a significant decrease in the expression of miR-21 and increase in the expression of miR-34a, miR-125b, and miR16 by oleuropein and/or cisplatin in ovarian cancer cells. SignificanceAltogether, these data revealed that oleuropein regulated the expression of the above-mentioned miRNAs in ovarian cancer cells, which potentially resulted in apoptosis induction, cell proliferation inhibition, and cisplatin resistance decline in ovarian cancer cells. To confirm the results of this study, it is suggested that similar experiments be performed in animal models of ovarian cancer.

Transcriptome Remodeling in Gradual Development of Inverse Resistance between Paclitaxel and Cisplatin in Ovarian Cancer Cells

Resistance to anti-cancer drugs is the main challenge in oncology. In pre-clinical studies, established cancer cell lines are primary tools in deciphering molecular mechanisms of this phenomenon. In this study, we proposed a new, transcriptome-focused approach, utilizing a model of isogenic cancer cell lines with gradually changing resistance. We analyzed trends in gene expression in the aim to find out a scaffold of resistance development process. The ovarian cancer cell line A2780 was treated with stepwise increased concentrations of paclitaxel (PTX) to generate a series of drug resistant sublines. To monitor transcriptome changes we submitted them to mRNA-sequencing, followed by the identification of differentially expressed genes (DEGs), principal component analysis (PCA), and hierarchical clustering. Functional interactions of proteins, encoded by DEGs, were analyzed by building protein-protein interaction (PPI) networks. We obtained human ovarian cancer cell lines with gradually developed resistance to PTX and collateral sensitivity to cisplatin (CDDP) (inverse resistance). In their transcriptomes, we identified two groups of DEGs: (1) With fluctuations in expression in the course of resistance acquiring; and (2) with a consistently changed expression at each stage of resistance development, constituting a scaffold of the process. In the scaffold PPI network, the cell cycle regulator—polo-like kinase 2 (PLK2); proteins belonging to the tumor necrosis factor (TNF) ligand and receptor family, as well as to the ephrin receptor family were found, and moreover, proteins linked to osteo- and chondrogenesis and the nervous system development. Our cellular model of drug resistance allowed for keeping track of trends in gene expression and studying this phenomenon as a process of evolution, reflected by global transcriptome remodeling. This approach enabled us to explore novel candidate genes and surmise that abrogation of the osteomimic phenotype in ovarian cancer cells might occur during the development of inverse resistance between PTX and CDDP.

Osteopontin‑c isoform inhibition modulates ovarian cancer cell cisplatin resistance, viability and plasticity.

Osteopontin (OPN) is upregulated in several types of tumor and has been associated with chemoresistance. However, the contribution of OPN splicing isoforms (OPN-SIs) to chemoresistance requires further investigation. The present study aimed to evaluate the expression patterns of each tested OPN-SI in cisplatin (CDDP)-resistant ovarian carcinoma cell lines, focusing on the role of the OPN-c isoform (OPNc) in drug resistance. ACRP ovarian cancer cells resistant to CDDP, as well as their parental cell line A2780, were used. Analyses of the transcriptional expression of OPN-SIs, epithelial-mesenchymal transition (EMT) markers and EMT-related cytokines were performed using reverse transcription-quantitative PCR. OPNc was silenced in ACRP cells using anti-OPNc DNA oligomers and stably overexpressed by transfecting A2780 cells with a mammalian expression vector containing the full length OPNc cDNA. Functional assays were performed to determine cell proliferation, viability and colony formation. The results demonstrated that among the three tested OPN-SIs, OPNc was the most upregulated transcript in the ACRP cells compared with the parental A2780 cells. In addition, the expression levels of P-glycoprotein multidrug transporter were upregulated in CDDP-resistant ACRP cells compared with those in A2780 cells. OPNc knockdown sensitized ACRP cells to CDDP treatment and downregulated P-gp expression levels compared with those in the negative control group. Additionally, silencing of OPNc impaired cell proliferative and colony formation abilities, as well as reversed the expression levels of EMT markers and EMT-related cytokines compared with those in the negative control cells. Notably, although stable OPNc overexpression resulted in increased A2780 cell proliferation, it notably increased CDDP sensitivity compared with that in the cells transfected with a control vector. These results suggested that OPNc silencing may represent a putative approach to sensitize resistant ovarian cancer cells to chemotherapeutic agents.

MiR-513a-3p inhibits EMT mediated by HOXB7 and promotes sensitivity to cisplatin in ovarian cancer cells.

Our aim was to investigate the biological function and mechanism of action of miR-513a-3p in ovarian cancer cells. In this study, qRT-PCR, Western blots, and immunohistochemistry experiments were among the methods used to examine the expression of miR-513a-3p, HOXB7, and related transcripts within ovarian cancer cells. An MTT assay was conducted to evaluate the viability of ovarian cancer cells in the presence of cisplatin. Transwell and wound-healing assays were performed to examine cell migration and invasion. Dual-Luciferase reporter assays were used to evaluate interactions among the aforementioned target genes. In vivo tumorigenesis experiments were conducted to verify biological effects of miR-513a-3p and HOXB7. HOXB7 expression was relatively higher and MiR-513a-3p expression was relatively lower in ovarian cancer cells. Down-regulated expression of miR-513a-3p promoted cell movement via its ability to regulate epithelial-mesenchymal transition (EMT). Furthermore, decreased expression of miR-513a-3p resulted in increased sensitivity to cisplatin and resulted in poor prognosis in ovarian cancer patients who had relapsed after treatment with cisplatin. However, HOXB7 reversed the impact of miR-513a-3p in ovarian cancer cells. These results suggested that miR-513a-3p altered EMT mediated by HOXB7 and cisplatin-resistance. MiR-513a-3p plays a critical role in promoting sensitivity to cisplatin and tumorigenesis via targeting HOXB7 in ovarian cancer.

Apigenin induces apoptosis and counteracts cisplatin-induced chemoresistance via Mcl-1 in ovarian cancer cells.

Ovarian cancer (OC) is one of the prominent causes of mortality in female patients diagnosed with gynecologic malignancies. While it has previously been demonstrated that apigenin inhibits cell growth in colon and breast cancer cells, the effect of apigenin in OC cells is not fully understood. Therefore, the aim of the present study was to investigate the impact of apigenin on cell death and resistance to cisplatin in OC cells. It was found that apigenin inhibited proliferation, hindered cell cycle progression and promoted SKOV3 cell apoptosis. Moreover, these effects were also observed in cisplatin-resistant SKOV3/DDP cells. Furthermore, apigenin reduced the mitochondrial transmembrane potential, and elevated the ratios of cleaved caspase-3/caspase-3 and Bax/Bcl-2 in the two cell types. Reverse transcription-quantitative PCR and western blotting results demonstrated that apigenin significantly downregulated Mcl-1 at the transcriptional and translational levels in SKOV3 and SKOV3/DDP cells, which was responsible for its cytotoxic functions and chemosensitizing effects. Collectively, the present results identified the impact of apigenin on OC cell death and resistance to cisplatin, and the potential molecular mechanisms. However, additional studies are required to further elucidate the underlying mechanisms.

Sulforaphane enhances the cisplatin sensitivity through regulating DNA repair and accumulation of intracellular cisplatin in ovarian cancer cells

ObjectivesCisplatin is commonly applied as anticancer agent for various cancers, including ovarian cancer. Unfortunately, the drug resistance frequently occurred which obstructing the effect of cisplatin on tumors. The goal of our research was to investigate the reversal actions and the potential mechanisms of sulforaphane (SFN) on cisplatin resistance in ovarian carcinoma. MethodsThe A2780 and IGROV1 cells and their cisplatin resistance cells A2780/CP70 and IGROV1-R10 were used in this study. Cell viability was detected by CCK-8. The DNA repair was measured by comet assay. The cisplatin transporter proteins were measured with western blotting. The concentration of intracellular cisplatin was detected by HPLC. The luciferase activity assay was applied to determine the target site of miR-30a-3p on the 3′UTR of ERCC1 and ATP7A. A2780/CP70 and IGROV1-R10 xenograft mouse model were established to confirm the antineoplastic action of SFN combined with cisplatin. ResultsSFN reversed the resistance of A2780/CP70 and IGROV1-R10 ovarian carcinoma cells to cisplatin through inducing DNA damage and accumulation of intracellular cisplatin. SFN treatment notably increased miR-30a-3p expression, which was decreased in cisplatin-resistant cells. Moreover, overexpressed miR-30a-3p enhanced the sensitivity of A2780/CP70 and IGROV1-R10 cells to cisplatin treatment, and inhibiting miR-30a-3p activity abated the reversal actions of SFN on cisplatin resistance. The luciferase assay findings showed that miR-30a-3p binds to ERCC1 and ATP7A which are the key regulators for DNA repair and cisplatin transportation. ConclusionsOur findings indicated that SFN could enhance cisplatin sensitivity of ovarian carcinoma cells through up-regulating miR-30a-3p to induce DNA damage and accumulation of intracellular cisplatin.

MiR-203 Regulates DJ-1/Phosphatase and Tensin Homologue Deleted on Chromosome Ten/Phosphatidylinositol-3 Kinase/Protein Kinase B Pathway and Affects Proliferation, Apoptosis and Cisplatin Resistance of Ovarian Cancer Cells

DJ-1 negatively regulates PTEN and plays a role in tumorigenesis and progression. Abnormal miR-203 expression is associated with ovarian cancer. miR-203 was predicted to have a relationship with DJ-1 3-UTR. Our study assessed miR-203’s role in ovarian cancer cell cisplatin (CDDP) resistance. The CDDP-resistant cell line SKOV3/CDDP was established and compared with the expression of miR-203 and DJ-1 in the parental SKOV3 cells. SKOV3/CDDP cells were separated into miR-NC group and miR-203 mimic group followed by analysis of DJ-1, PTEN and p-AKT expression, cell apoptosis and proliferation. There was a targeted relationship between miR-203 and DJ-1 mRNA. miR-203 and PTEN protein expression in SKOV3/CDDP cells was significantly reduced compared to SKOV3 cells with significantly upregulated DJ-1. miR-203 mimic significantly upregulated miR-203, decreased DJ-1 and p-AKT protein expression and elevated PTEN expression along with increased cell apoptosis and reduced cell proliferative ability. Decreased miR-203 expression and increased DJ-1 expression participate in drug resistance in ovarian cancer cells. miR-203 inhibits DJ-1 expression, affects PTEN-PI3K/AKT signaling, inhibits ovarian cancer cell proliferation and promotes apoptosis, and reduces CDDP resistance.

Investigating the Effects of Morphine on Survival and Sensitivity to Cisplatin in Ovarian Cancer Cells

Morphine as an analgesic drug is used frequently in cancer patients. Contradictory results have been achieved from previous studies related to morphine effects in different concentrations. In current study, we examined the effect of clinical concentrations of morphine on A2780Cp cell line related to ovarian cancer. Moreover, its effect on the cytotoxicity of cisplatin was investigated. A2780CP cells were cultured in RPMI1640 medium and treated with clinical doses of morphine alone or in combination with cisplatin. The rate of cell proliferation was measured using MTT assay, morphological changes of nuclei were revealed by 4′,6-diamidino-2-phenylindole (DAPI) staining, and expression of B-cell lymphoma 2 (Bcl-2) was measured using flowcytometry. MTT assay results showed clinical concentration of morphine had no effect on viability of A2780CP cells and toxicity of cisplatin. DAPI staining revealed no chromatin condensation in presence of morphine, and flowcytometry analysis showed that the expression of Bcl-2 in treated cells did not differ from control cells. In accordance with findings in other kinds of cancer, our results demonstrated that morphine did not interact with the function of cispatin in ovarian cancer. This finding can be considered in clinical applications of morphine.

ABT737 enhances ovarian cancer cells sensitivity to cisplatin through regulation of mitochondrial fission via Sirt3 activation

AimsThe poor prognosis of ovarian cancer is mainly caused by chemotherapy resistance. Studies show that the Bcl-2 inhibitor ABT737 can significantly improve the effect of cisplatin and induce mitochondrial pathway apoptosis. However, the mechanism of ABT737 increases sensitivity to cisplatin by regulating mitochondrial function remains unclear in ovarian cancer cells. Sirt3, as a histone deacetylase, is involved in the regulation of mitochondrial function in cancers. In this study, we intend to explore the mechanistic link between Sirt3 and mitochondrial dysfunction induced by ABT737 and cisplatin in ovarian cancer cells. Main methodsApoptosis was examined by flow cytometry following Annexin V and PI staining. Sirt3 activity was assessed using Sirt3 deacetylase fluorometric assay. The mitochondrial membrane potential was examined by flow cytometry following JC-1 staining. Overexpression and knock-down of Sirt3 were confirmed by western blot analysis. Mitochondrial fission/fusion dynamics were detected by immunofluorescence staining or western blot analysis. Key findingsCisplatin accompanied with ABT737 promoted apoptosis and decreased mitochondrial membrane potential. ABT737 enhanced the sensitivity of ovarian cancer cells to cisplatin, which was partly achieved by activating Sirt3 to regulate the mitochondrial fission process. SignificanceThis study identified the activation of Sirt3 played an important role in increasing sensitivity of ovarian cancer cells to cisplatin induced by ABT737. Furthermore, Sirt3 might represent a potential therapeutic target for ovarian cancer.

ZEB1 Promotes Chemoresistance to Cisplatin in Ovarian Cancer Cells by Suppressing SLC3A2

Ovarian cancer is one of the deadliest gynecological malignancies in women. Chemoresistance has been a major obstacle for ovarian cancer treatment. Zinc finger E-box-binding homeobox 1 (ZEB1) is an important regulator of tumor development in various types of cancer. Abnormal expression of SLC3A2 (CD98hc), a type 2 transmembrane cell surface molecule, has been described in several cancers. This study was designed to investigate the role of ZEB1 and SLC3A2 in the chemoresistance to cisplatin in ovarian cancer cells. We found that ZEB1 was increased in cisplatin-resistant SKOV3/DPP cells. Downregulation of ZEB1 significantly decreased cell viability in response to cisplatin, increased cis­platin-induced apoptosis, and decreased migration and invasion in the presence of cisplatin. In addition, downregulation of ZEB1 decreased the volume and weight of implanted tumors. SLC3A2 was decreased in cisplatin-resistant SKOV3/DPP cells. Upregulation of SLC3A2 significantly decreased cell viability in response to cisplatin, increased cisplatin-induced apoptosis, and decreased migration and invasion in the presence of cisplatin. Moreover, upregulation of SLC3A2 decreased the volume and weight of implanted tumors. Downregulation of ZEB1 resulted in a significant increase of SLC3A2 expression. Moreover, downregulation of SLC3A2 significantly inhibited ZEB1 knockdown-mediated inhibition of cisplatin-resistance. ZEB1-mediated regulation of SLC3A2 was involved in the chemoresistance to cisplatin in ovarian cancer cells. Overall, we provide new insights into the mechanism of chemoresistance to cisplatin in ovarian cancer cells. ZEB1/SLC3A2 may be promising therapeutic targets for enhancement of the sensitivity of ovarian cancer cells to cisplatin-mediated chemotherapy.

Abstract 3522: Both mitochondrial function and composition of BCL2 family proteins determines sensitivity to Cisplatin in ovarian cancer cells and are promising targets to overcome Cisplatin resistance in ovarian cancer

Abstract Mitochondria are critical target structures of platinum drugs. To study whether mitochondrial activities of Cisplatin are critical for its cytotoxic function we studied mitochondrial mass, mitochondrial function and composition of pro- and anti-apoptotic BCL2 family proteins in three resistant and three sensitive high-grade serous carcinoma (HGSC) cell lines. Sensitive cell lines differed from resistant cells by higher mitochondrial mass (MM), higher levels of mitochondrial reactive oxygen species (mtROS) and higher basal oxygen consumption rate (OCR) levels as well as a higher ratio of pro- vs. anti-apoptotic BCL2 family proteins. Cell death upon Cisplatin in sensitive cells was dependent on induction of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP), induction of BAX-BAK pores and caspases. Genetically alteration of the BCL2 family protein ratio by siRNA mediated knockdown of pro-apoptotic NOXA reduced acute response in sensitive cell lines, whereas knockdown of anti-apoptotic BCLw rendered resistant cells sensitive. In analogy, pharmacological inhibition of anti-apoptotic proteins by ABT737 also completely re-sensitized Cisplatin resistant cell lines. Cisplatin exposure increased MM, mtROS and OCR in both sensitive and insensitive HGSC cell lines. However, these parameters reached higher peak levels in cell lines sensitive to induction of cell death by Cisplatin. Knockdown of PGC-1α (the master regulator of mitochondrial biogenesis) partially rescues sensitive cells from apoptosis. In addition, pharmacological inhibition of ATP synthase by Oligomycin A blocks MMP and mtROS induction by Cisplatin and inhibits Cisplatin induced cell death. This supports the hypothesis that induction of mitochondria leading to increased release of mtROS contributes to cell death by Cisplatin. We finally tested whether other modulators of mitochondrial function restore sensitivity to Cisplatin in resistant cells. Whereas Complex-I and Complex-III inhibitors did not affect cytotoxicity of Cisplatin, the iron chelator VLX600 had significant synergistic activity with Cisplatin in resistant cancer cells. VLX600 inhibits oxygen consumption almost completely in combination with Cisplatin whereas both compounds had no significant effect on survival when used as monotherapy. In conclusion, cytotoxicity of Cisplatin in HGSC cell lines depends on efficient induction of MM and mtROS. Resistance can efficiently be targeted by modulating the mitochondrial function by VLX600. These observations support the view that mitochondria are attractive targets for increasing Cisplatin activity on cancer cells. Citation Format: Markus Kleih, Simon Heine, Kathrin Böpple, Meng Dong, Heiko van der Kuip, Walter E. Aulitzky. Both mitochondrial function and composition of BCL2 family proteins determines sensitivity to Cisplatin in ovarian cancer cells and are promising targets to overcome Cisplatin resistance in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3522.

Luteolin promotes the sensitivity of cisplatin in ovarian cancer by decreasing PRPA1-medicated autophagy

Luteolin (LUT) is a flavone universally presented in plants. It shows an anti-carcinogenic effect in different cancers and could increase the sensitivity of cisplatin in colorectal cancer cell lines through Nrf2 pathway. However, the effect of luteolin on the sensitivity to ovarian cancer cells has not been studied. In this study, luteolin was found to suppress autophagy with reduced expression of LC3-II, but enhanced the inhibition of cell vitality and promoted apoptosis induced by cisplatin, leading to restoration of the sensitivity to cisplatin in ovarian cancer cells through CCK-8, flow cytometry and immunofluorescent assays. Although cisplatin elevated the PARP1 for cell survival, the cisplatin-induced expression of PARP1 was inhibited by luteolin a dose- and time- dependent manner through Q-PCR and WB assays. Further, PARP1 siRNA could further improve the LUT-induced inhibition of cell vitality and restore the sensitivity to cisplatin with reduced LC3-II levels. Our present work demonstrate that LUT can suppresses autophagy but enhance apoptosis induced by cisplatin and promote the sensitivity to cisplatin through suppressing the expression of RARP1 in ovarian cancer.

DUOXA1-mediated ROS production promotes cisplatin resistance by activating ATR-Chk1 pathway in ovarian cancer

The acquisition of resistance is a major obstacle to the clinical use of platinum drugs for ovarian cancer treatment. Increase of DNA damage response is one of major mechanisms contributing to platinum-resistance. However, how DNA damage response is regulated in platinum-resistant ovarian cancer cells remains unclear. Using quantitative high throughput combinational screen (qHTCS) and RNA-sequencing (RNA-seq), we show that dual oxidase maturation factor 1 (DUOXA1) is overexpressed in platinum-resistant ovarian cancer cells, resulting in over production of reactive oxygen species (ROS). Elevated ROS level sustains the activation of ATR-Chk1 pathway, leading to resistance to cisplatin in ovarian cancer cells. Moreover, using qHTCS we identified two Chk1 inhibitors (PF-477736 and AZD7762) that re-sensitize resistant cells to cisplatin. Blocking this novel pathway by inhibiting ROS, DUOXA1, ATR or Chk1 effectively overcomes cisplatin resistance in vitro and in vivo. Significantly, the clinical studies also confirm the activation of ATR and DOUXA1 in ovarian cancer patients, and elevated DOUXA1 or ATR-Chk1 pathway correlates with poor prognosis. Taken together, our findings not only reveal a novel mechanism regulating cisplatin resistance, but also provide multiple combinational strategies to overcome platinum-resistance in ovarian cancer.