Sensitivity Of Ovarian Cancer Cells Research Articles

Iron promotes ovarian cancer malignancy and advances platinum resistance by enhancing DNA repair via FTH1/FTL/POLQ/RAD51 axis

Iron is crucial for cell DNA synthesis and repair, but an excess of free iron can lead to oxidative stress and subsequent cell death. Although several studies suggest that cancer cells display characteristics of ‘Iron addiction’, an ongoing debate surrounds the question of whether iron can influence the malignant properties of ovarian cancer. In the current study, we initially found iron levels increase during spheroid formation. Furthermore, iron supplementation can promote cancer cell survival, cancer spheroid growth, and migration; vice versa, iron chelators inhibit this process. Notably, iron reduces the sensitivity of ovarian cancer cells to platinum as well. Mechanistically, iron downregulates DNA homologous recombination (HR) inhibitor polymerase theta (POLQ) and relieves its antagonism against the HR repair enzyme RAD51, thereby promoting DNA damage repair to resist chemotherapy-induced damage. Additionally, iron tightly regulated by ferritin (FTH1/FTL) which is indispensable for iron-triggered DNA repair. Finally, we discovered that iron chelators combined with platinum exhibit a synergistic inhibitory effect on ovarian cancer in vitro and in vivo. Our findings affirm the pro-cancer role of iron in ovarian cancer and reveal that iron advances platinum resistance by promoting DNA damage repair through FTH1/FTL/POLQ/RAD51 pathway. Our findings highlight the significance of iron depletion therapy, revealing a promising avenue for advancing ovarian cancer treatment.

ATP6V1B1 regulates ovarian cancer progression and cisplatin sensitivity through the mTOR/autophagy pathway.

Early detection and effective chemotherapy for ovarian cancer, a serious gynecological malignancy, require further progress. This study aimed to investigate the molecular mechanism of ATPase H+-Transporting V1 Subunit B1 (ATP6V1B1) in ovarian cancer development and chemoresistance. Our data show that ATP6V1B1 is upregulated in ovarian cancer and correlated with decreased progression-free survival. Gain- and loss-of-function experiments demonstrated that ATP6V1B1 promotes the proliferation, migration, and invasion of ovarian cancer cells in vitro, while ATP6V1B1 knockout inhibits tumor growth in vivo. In addition, knocking down ATP6V1B1 increases the sensitivity of ovarian cancer cells to cisplatin. Mechanistic studies showed that ATP6V1B1 regulates the activation of the mTOR/autophagy pathway. Overall, our study confirmed the oncogenic role of ATP6V1B1 in ovarian cancer and revealed that ATP6V1B1 promotes ovarian cancer progression via the mTOR/autophagy axis.

A miRNA-7704/IL2RB/AKT feedback loop regulates tumorigenesis and chemoresistance in ovarian cancer

Ovarian cancer is one of the most common gynecological tumors worldwide. Despite the availability of multiple treatments for ovarian cancer, its resistance to chemotherapy remains a significant challenge. miRNAs play crucial roles in the initiation and progression of cancer by affecting processes such as differentiation, proliferation, and chemoresistance. According to microarray and qPCR analyses, miR-7704 is significantly downregulated in cisplatin-resistant cells compared to parental cells. In this study, we found that miR-7704 inhibited the proliferation and promoted cisplatin sensitivity of ovarian cancer cells in vitro and in vivo. Moreover, ectopic expression of miR-7704 had the same effect as IL2RB knockdown. Further mechanistic studies revealed that miR-7704 played an inhibitory role by regulating IL2RB expression to inactivate the AKT signaling pathway. Furthermore, IL2RB reversed the miR-7704 mediated resistance to cisplatin in ovarian cancer. Based on these findings, miR-7704 and IL2RB show the potential as novel therapeutic targets for ovarian cancer.

Anlotinib Inhibits Ovarian Cancer and Enhances Cisplatinum Sensitivity via Suppressing NOTCH2 Expression and Stemness.

The prognosis of ovarian cancer (OC) patients is especially poor for patients with chemotherapy resistance. Anlotinib, a novel multi-targeted tyrosine kinase inhibitor, has shown encouraging clinical efficacy in several tumor types. The aim of the present study was to examine the inhibitory efficacy and mechanism of anlotinib on the proliferation and chemosensitivity of OC cells. The inhibitory effects of Anlotinib on SKOV3 and OVCAR3 OC cells were examined using CCK-8 cell-viability, colony-formation, flow-cytometry, transwell-migration and sphere-formation assays. A xenograft mouse model was used for in vivo studies. RT-qPCR and western blotting were used to detect gene expression. Molecular targets of anlotinib were elevated in OC patient tumors. Anlotinib significantly inhibited ovarian cancer cell proliferation and migration in vitro. Anlotinib enhanced the sensitivity of ovarian cancer cells to cisplatinum both in vitro and in vivo. Anlotinib suppressed sphere formation and the stemness phenotype of OC cells by inhibiting NOTCH2 expression. Anlotinib inhibits ovarian cancer and enhances cisplatinum sensitivity, suggesting its future clinical promise.

Abstract 4318: CD24 enhances cisplatin resistance in ovarian cancer by suppressing autophagy

Abstract Ovarian cancer is one of the most common gynecological cancers with the highest mortality rate. Most patients are diagnosed with advanced disease and will relapse due to chemoresistance. CD24, a highly glycosylated GPI-anchored membrane protein. Recent studies have shown that CD24 expression is significantly up-regulated in ovarian cancer and is associated with chemotherapy resistance, and CD24 also plays an inhibitory role in tumor immunity by binding to Siglec-10 on macrophages. However, the molecular mechanisms of how CD24 affects chemotherapy resistance in ovarian cancer remain unclear. In this study, we used shRNAs to knockdown CD24 and explore the impact and mechanism of CD24 on the chemotherapy resistance of ovarian cancer cells. The results showed that knockdown of CD24 in ovarian cancer cells SKOV3 and TOV21G significantly reduced cell proliferation and arrested the cell cycle in S phase. Knockdown of CD24 also significantly increased the sensitivity of ovarian cancer cells to cisplatin but had no effect on paclitaxol treatment. Further experiments showed that knockdown of CD24 increased cisplatin sensitivity by promoting autophagy-induced cell death. In addition, Gene Set Enrichment Analysis (GSEA) was used to analyze the correlation between the expression of CD24 and its biological functions in the TCGA ovarian cancer dataset. The results showed that CD24 is mostly correlated to cell proliferation and autophagy-related pathways in ovarian cancers. Further mouse xenograft tumor transplantation experiments also confirmed that knockdown of CD24 reduced tumor size and increased sensitivity to cisplatin treatment by increasing cell autophagy. Taken together, these results indicate that CD24 regulates cell growth and chemoresistance in ovarian cancer cells and that inhibition of CD24 may be helpful in the treatment of ovarian cancer. Citation Format: Yuh-Ling Chen, Tse-Ming Hong, Yu-Yi Wen. CD24 enhances cisplatin resistance in ovarian cancer by suppressing autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4318.

Abstract A035: Genome-wide CRISPRi screening reveals determinants of platinum sensitivity and resistance in high-grade serous ovarian cancer

Abstract A035: Genome-wide CRISPRi screening reveals determinants of platinum sensitivity and resistance in high-grade serous ovarian cancer

Abstract B095: Tenascin C promotes ovarian cancer stem cells interactions with the niche

Abstract Background: Effective treatment of ovarian cancer (OC) is greatly impacted by advanced, late-stage diagnosis which usually presents with intra-peritoneal metastases, chemoresistance and high recurrence. The development of intra-peritoneal metastases is correlated with the formation of multicellular spheroids disseminated in the peritoneal fluid. Spheroid formation is promoted by a change of cell adhesion properties, enhanced secretion of extracellular matrix (ECM) components that stiffen the tumor stroma and promote the aberrant activation of oncogenic processes, including survival, invasion, and stemness. Tenascin C (TNC) is one of the molecules secreted in the ECM and correlates with migration and metastatic progression in a variety of carcinomas. However, the functional role of TNC in spheroid formation and in the maintenance of the platinum resistant ovarian cancer stem phenotype has not been investigated yet. We tested the hypothesis that the increased expression of TNC and its secretion in the ECM compartment promotes survival of OCSCs, supports OC spheroid formation and tumor progression. Methods: We compared TNC expression in OC cells grown as spheroids and monolayers and in chemoresistant vs sensitive OC cells by realtime-PCR and Western Blot (WB). TNC blockade by siRNA knockdown (KD) was evaluated in combination with carboplatin on spheroid assay, colony formation, and by qPCR of stemness related gene expression. Chromatin immunoprecipitation (ChIP) assay detected the interaction between the β-catenin and the TNC promoter. Results: OC cells grown as spheroids showed a significant increase in TNC expression compared to monolayers. Our results also demonstrated an increase in TNC expression levels in platinum resistant OC cell lines when compared to the platinum sensitive counterpart. A comparison of normal adjacent ovarian epithelium and primary OC tumors on a multitissue array revealed that TNC expression coincided with a pro-tumorigenic phenotype (n=88, P<0.001), correlating with poor outcome. TNC-KD in combination with carboplatin led to a significant decrease in the expression levels of stemness-related genes, spheroid and colony formation. Mechanistically, b-catenin-KD decreased TNC expression levels and β-catenin coimmunoprecipitated with the TNC promoter, suggesting that TNC is a direct β-catenin target. Additionally, OC spheroids treated with the Wnt ligand WNT-3A showed increased TNC expression compared to control untreated cells, as demonstrated by WB. Importantly, the enhanced expression of TNC was followed by its secretion in the ECM compartment, as observed via immunofluorescence imaging, implying a direct role of TNC in the ECM-rearrangement which is responsible for CSC maintenance and spheroid formation. Conclusions: TNC is strongly linked to chemoresistance and is regulated by the oncogenic β-catenin pathway. Our data suggest that strategies aimed at interfering with TNC expression and/or secretion along with carboplatin treatment could be a potential combination therapy in OC. Citation Format: Amber Rogers, Maya Shebeshi, Morganna Gordon, Rula Atwani, Virginie Lazar, Salvatore Condello. Tenascin C promotes ovarian cancer stem cells interactions with the niche [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B095.

Abstract B007: NAD+ metabolism drives PARPi resistance in ovarian cancer cells

Abstract NAD+ is a coenzyme for redox reactions and a cofactor for enzymes such as PARPs and Sirtuins. The nuclear enzyme PARP1 is a major consumer of NAD+, which is cleaved during the catalytic activation of PARP1 in response to DNA damage. PARP1 inhibitors compete with NAD+ for the catalytic site of PARP1 and reduce the catalytic activity of PARP1 and impair DNA damage repair. Recently PARP inhibitors (PARPi) have shown efficacy in the treatment of ovarian cancers and most patients with defects in homologous repair of DNA damage are now on PARPi maintenance. But, heterogeneous responses to PARPi is limiting their clinical efficacy. To identify the mechanisms of PARPi resistance, we generated a panel of ovarian cancer cells with acquired resistance to niraparib (PARPiR), an FDA approved PARP inhibitor. We demonstrated that the PARPiR cells are also resistant to other FDA approved PARP inhibitors rucaparib and olaparib. This data suggested that a common mechanism of resistance underlies poor response to the FDA approved PARP inhibitors. Since PARP1 activity is tightly controlled by the cellular NAD+ levels, we next investigated the role of NAD+ biosynthesis in PARPi resistance. Metabolomic profiling of the parental and PARPiR cells demonstrated that PARPiR cells have elevated levels of NAD+ metabolism. Indeed, treating the PARPiR cells with inhibitors of NAD+ synthesis restored the sensitivity to PARP inhibitors. Moreover, culturing the previously sensitive parental ovarian cancer cells in NAD+ precursors decreased their sensitivity to PARP inhibitors. These data collectively demonstrated that high levels of NAD+ metabolism causes PARP inhibitor resistance in ovarian cancer cells. Complementary to the metabolomic analysis, results from phenotypic assays in PARPiR cells revealed that high levels of NAD+ maintain cellular quiescence in PARPiR cells. In summary, our results demonstrated that high levels of NAD+ biosynthesis causes PARPi resistance by maintaining cellular quiescence. There is an urgent need to identify the mechanisms of resistance to PARP inhibitors to increase their clinical efficacy. Our study identified that maintenance of quiescence is a fundamental mechanism of PARPi resistance. We also demonstrated that inhibiting NAD+ biosynthesis reverses PARP inhibitor resistance. Citation Format: Subin Myong, Hardik Shah, Benedikt Nagele, Reshma Rajesh, Sridevi Challa. NAD+ metabolism drives PARPi resistance in ovarian cancer cells [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B007.

E2F1 mediates competition, proliferation and response to cisplatin in cohabitating resistant and sensitive ovarian cancer cells.

Tumor heterogeneity is one of the key factors leading to chemo-resistance relapse. It remains unknown how resistant cancer cells influence sensitive cells during cohabitation and growth within a heterogenous tumors. The goal of our study was to identify driving factors that mediate the interactions between resistant and sensitive cancer cells and to determine the effects of cohabitation on both phenotypes. We used isogenic ovarian cancer (OC) cell lines pairs, sensitive and resistant to platinum: OVCAR5 vs. OVCAR5 CisR and PE01 vs. PE04, respectively, to perform long term direct culture and to study the phenotypical changes of the interaction of these cells. Long term direct co-culture of sensitive and resistant OC cells promoted proliferation (p < 0.001) of sensitive cells and increased the proportion of cells in the G1 and S cell cycle phase in both PE01 and OVCAR5 cells. Direct co-culture led to a decrease in the IC50 to platinum in the cisplatin-sensitive cells (5.92 µM to 2.79 µM for PE01, and from 2.05 µM to 1.51 µM for OVCAR5). RNAseq analysis of co-cultured cells showed enrichment of Cell Cycle Control, Cyclins and Cell Cycle Regulation pathways. The transcription factor E2F1 was predicted as the main effector responsible for the transcriptomic changes in sensitive cells. Western blot and qRT-PCR confirmed upregulation of E2F1 in co-cultured vs monoculture. Furthermore, an E2F1 inhibitor reverted the increase in proliferation rate induced by co-culture to baseline levels. Our data suggest that long term cohabitation of chemo-sensitive and -resistant cancer cells drive sensitive cells to a higher proliferative state, more responsive to platinum. Our results reveal an unexpected effect caused by direct interactions between cancer cells with different proliferative rates and levels of platinum resistance, modelling competition between cells in heterogeneous tumors.

Peroxiredoxin-1 as a molecular chaperone that regulates glutathione S-transferase P1 activity and drives mutidrug resistance in ovarian cancer cells

Ovarian cancer is among the most prevalent gynecological malignancies around the globe. Nonetheless, chemoresistance continues to be one of the greatest obstacles in the treatment of ovarian cancer. Therefore, understanding the mechanisms of chemoresistance and identifying new treatment options for ovarian cancer patients is urgently required. In this study, we found that the mRNA and protein expression levels of PRDX1 were significantly increased in cisplatin resistant A2780/CDDP cells. Cell survival assays revealed that PRDX1 depletion substantially increased ovarian cancer cell sensitivity to cisplatin, docetaxel, and doxorubicin. Additionally, PRDX1 significantly increased GSTP1 activity, resulting in multidrug resistance. Biochemical experiments showed that PRDX1 interacted with GSTP1 through Cysteine 83, which regulated GSTP1 activity as well as chemotherapy resistance in ovarian cancer cells. Our findings indicate that the molecular chaperone activity of PRDX1 is a promising new therapeutic target for ovarian cancer.

Abstract C002: Identification of biomarkers predictive of sensitivity to the CHK1/2 inhibitor ACR-368 using high-resolution phosphoproteomics and development of an ACR-368-tailored patient responder identification 3-marker test, ACR-368 OncoSignature

Abstract Introduction ACR-368 (prexasertib) is a potent and selective CHK1/2 inhibitor with demonstrated durable, single-agent activity in patients with advanced solid tumors. Genomic biomarkers have been unsuccessful in predicting response to ACR-368 due in part to the complex genetic changes in cancer that translate into dysregulated protein signaling pathways. To address this challenge, we sought to identify protein-based, predictive biomarkers that measure the ACR-368-sensitive dysregulated signaling driving tumorigenesis using our proprietary approach, AP3 (Acrivon Predictive Precision Proteomics). Methods ACR-368 anticancer activity was measured in a panel of ovarian cancer cell lines using CellTiter-Glo. Quantitative phosphoproteomics was performed on ACR-368 sensitive and resistant ovarian cancer cell lines using data-independent acquisition mass spectrometry (DIA-MS). Kinase activity inference analysis and signaling pathway analyses were conducted to uncover ACR-368-regulated pathways associated with tumorigenesis. A quantitative, multiplexed immunofluorescent (IF) assay was developed based on three biomarkers, termed ACR-368 OncoSignature. Ovarian PDX studies were conducted in female athymic nude or CB-17 Scid mice. Results ACR-368 demonstrated diverse anti-proliferative activity in ovarian cancer cell lines. Phosphoproteome-profiling analysis from ACR-368 sensitive and resistant cells exposed to ACR-368 yielded &amp;gt;17,000 confidently localized phospho-sites (localization probability &amp;gt; 0.75), with 8272 being significantly regulated by ACR-368 (FC &amp;gt; 1.5, Q-value &amp;lt; 0.05, Limma t-test). Unsupervised hierarchical clustering analysis revealed overrepresentation of ATM/ATR and CDK1/2-associated substrate sites in the upregulated group, while the downregulated group showed overrepresentation of CHK1-associated sites. Pathway enrichment analysis highlighted the differential regulation of the homology-directed repair (HDR) pathway between sensitive and non-sensitive ovarian cancer cells. Through analysis of HDR-related signaling networks, three functionally orthogonal predictive biomarkers were assembled into a quantitative multiplex in situ assay for FFPE tissue that provides a direct readout of a tumor’s dependency on the signaling axis inhibited by ACR-368. Quantitation of these biomarkers in cancer cell lines using the IF-based OncoSignature demonstrated efficient classification based on ACR-368 sensitivity. The assay accurately predicted sensitivity to ACR-368 across ovarian cancer PDX models with an AUC of 0.9 (95% confidence interval: 0.71 to 1; p-value = 0.025). Conclusions Employing our AP3 platform, which combines MS-based phosphoproteomics and quantitative multiplexed-IF staining of drug-tailored biomarkers, we developed a response-predictive test for ACR-368 that enables identification of responders to ACR-368 treatment. A clinical trial (NCT05548296) evaluating the efficacy of ACR-368 based on the OncoSignature test status is currently recruiting in patients with platinum-resistant ovarian, endometrial, and urothelial cancer. Citation Format: Caroline Wigerup, Michail Shipitsin, Ayesha Murshid, Lei Shi, Magnus E. Jakobsson, Dorte Bekker-Jensen, Sibgat Choudry, James Dunyak, David Proia, Jesper V. Olsen, Kristina Masson, Peter Blume-Jensen. Identification of biomarkers predictive of sensitivity to the CHK1/2 inhibitor ACR-368 using high-resolution phosphoproteomics and development of an ACR-368-tailored patient responder identification 3-marker test, ACR-368 OncoSignature [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C002.

Baicalein improves the chemoresistance of ovarian cancer through regulation of CirSLC7A6

PurposeThe present study aimed to investigate whether baicalein improves the sensitivity of resistant ovarian cancer cells to cisplatin.MethodsTranscriptomic sequencing and bioinformatics analysis were used to screen differentially expressed CirSLC7A6 in A2780 and A2780/CDDP cells. RT-qPCR was performed to examine the expression levels of CirSLC7A6, miR-2682-5p, and SLC7A6. Cell proliferation and apoptosis were examined using a Cell Counting Kit-8 assay and flow cytometry, and cell migration and invasion were analyzed using wound healing and Transwell assays. Cell suspensions were inoculated into the subcutaneous tissues of the bilateral interscapular region of nude mice. Saline, cisplatin, baicalein and cisplatin plus baicalein were intraperitoneally injected to observe the effects on tumor growth. Toxicity analyses in the liver and kidney were performed using H&E staining. RT-qPCR and immunohistochemistry were used to detect the expression of CirSLC7A6, miR-2682-5p, and SLC7A6 in tumor tissues, and western blot analysis was carried out to measure protein expression levels.ResultsCirSLC7A6 was markedly upregulated in A2780/CDDP cells compared with the A2780 cells. CirSLC7A6 knockdown notably increased the expression of miR-2682-5p and decreased SLC7A6 expression. The rates of inhibition and apoptosis in the group treated with a combination of cisplatin and baicalein were significantly higher than those of the cisplatin and baicalein groups of A2780/CDDP shCirSLC7A6 cells. In A2780/CDDP shCirSLC7A6 cells, migration and invasion were significantly higher in the cisplatin and baicalein groups, compared with the combined treatment group. In the A2780/CDDP shCirSLC7A6 cell xenograft, the tumor weight of the combined treatment group was significantly lower than that of the cisplatin and baicalein groups. In addition, the combination of cisplatin and baicalein did not induce higher levels of toxicity in the liver or kidney. Baicalein alone and in combination with cisplatin notably reduced the expression of CirSLC7A6 and SLC7A6, and increased the expression of miR-2682-5p in the A2780/CDDP shCirSLC7A6 cell xenograft. In A2780/CDDP shCirSLC7A6 cells, the expression levels of P-Akt, P-mTOR, P-Erk, Bcl-2 and MMP2 were lower in the combined treatment group than in the control group.ConclusionsTreatment with baicalein improved the sensitivity of ovarian cancer cells to cisplatin and inhibited cell proliferation, metastasis and tumor growth.

Polyethylenimine-based iron oxide nanoparticles enhance cisplatin toxicity in ovarian cancer cells in the presence of a static magnetic field.

Drug resistance in cancer cells is a major concern in chemotherapy. Cisplatin (CIS) is one of the most effective chemotherapeutics for ovarian cancer. Here, we investigated an experimental approach to increase CIS cytotoxicity and overcome cell resistance using nanoparticle-based combination treatments. Polyethylenimine (PEI)-based magnetic iron oxide nanocomplexes were used for drug delivery in genetically matched CIS-resistant (A2780/CP) and -sensitive (A2780) ovarian cancer cells in the presence of a 20 mT static magnetic field. Magnetic nanoparticles (MNPs) were synthesized and bonded to PEI cationic polymers to form binary complexes (PM). The binding of CIS to the PM binary complexes resulted in the formation of ternary complexes PM/C (PEI-MNP/CIS) and PMC (PEI-MNP-CIS). CIS cytotoxicity increased at different concentrations of CIS and PEI in all binary and ternary delivery systems over time. Additionally, CIS induced cell cycle arrest in the S and G2/M phases and reactive oxygen species production in both cell lines. Ternary complexes were more effective than binary complexes at promoting apoptosis in the treated cells. PEI-based magnetic nanocomplexes can be considered novel carriers for increasing CIS cytotoxicity and likely overcoming drug resistance of ovarian cancer cells.

The TGFBI gene and protein expression in topotecan resistant ovarian cancer cell lines

PurposeThe primary limiting factor in achieving cures for patients with cancer, particularly ovarian cancer, is drug resistance. The mechanisms of drug resistance of cancer cells during chemotherapy may include compounds of the extracellular matrix, such as the transforming growth factor-beta-induced protein (TGFBI). In this study, we aimed to analyze the TGFBI gene and protein expression in different sensitive and drug-resistant ovarian cancer cell lines, as well as test if TGFBI can be involved in the response to topotecan (TOP) at the very early stages of treatment. Materials and methodsIn this study, we conducted a detailed analysis of TGFBI expression in different ovarian cancer cell lines (A2780, A2780TR1, A2780TR2, W1, W1TR, SKOV-3, PEA1, PEA2 and PEO23). The level of TGFBI mRNA (QPCR), intracellular and extracellular protein (Western blot analysis) were assessed in this study. ResultsWe observed upregulation of TGFBI mRNA in drug-resistant cell lines and estrogen-receptor positive cell lines, which was supported by overexpression of both intracellular and extracellular TGFBI protein. We also showed the TGFBI expression after a short period of treatment of sensitive ovarian cancer cell lines with TOP. ConclusionThe expression of TGFBI in ovarian cancer cell lines suggests its role in the development of drug resistance.

Hsa_circ_0000585 promotes chemoresistance to cis-platin in epithelial cells of ovarian cancer by modulating autophagy

BackgroundChemoresistance, i.e., resistance to cisplatin (DDP), has been a major obstacle to ovarian cancer treatment. It has been found that circular RNAs (circRNAs) play vital roles in the tumorigenesis various cancers by regulating autophagy, while few studies focusing on cisplatin-resistance ovarian cancer (CROC). MethodsThe expressions of the circRNAs were detected by qRT-PCR. Short hairpin RNA targeting circRNA was used to explore the biological functions of the circRNA. Cell viability, autophagic flux, immunofluorescence, and xenograft tumors experiments were performed to further illustrate the underlying mechanisms. ResultsHsa_circ_0000585 was increased in cisplatin-resistant SKOV3/DDP cells. Stably knocking down hsa_circRNA_0000585 expression in SKOV3/DDP cells was established by RNA interference. We found that downregulation of hsa_circ_0000585 significantly enhanced the sensitivity of DDP/SkOV3 cells to DDP. In vivo study, hsa_circRNA_0000585 knockdown significantly decreased tumor volume in nude mice. Under the measurements of western blot and cellular immunofluorescence, hsa_circ_0000585 knockdown significantly inhibited the expression of Beclin1 and P62, indicating the autophagic flux was inhibited. Administrations with autophagic inhibitor “Chloroquine (CQ)” and autophagy activator “QX77” further confirmed that hsa_circ_0000585 knockdown resulted in autophagy inhibition. ConclusionsOverall, this study provided a new insight into the role of circRNAs in the mechanism of DDP-resistance in ovarian cancer. Hsa_circRNA_0000585 may be promising therapeutic targets for the enhancement of the sensitivity of ovarian cancer cells to cisplatin-mediated chemotherapy.

Tasquinimod enhances the sensitivity of ovarian cancer cells to cisplatin by regulating the Nur77-Bcl-2 apoptotic pathway.

Resistance to cisplatin (DDP) in ovarian cancer therapy has been a major clinical barrier. Drug-resistant cancers have been shown to downregulate the proapoptotic protein B-cell lymphoma-2 (Bcl-2) to inhibit apoptosis. Therefore, we explored whether tasquinimod could modulate resistance to DDP through apoptotic pathways. We aimed to explore the relationship between tasquinimod, Nur77-Bcl-2 apoptosis pathway and sensitivity of the ovarian carcinoma cell line SKOV3 and the DDP-resistant strain SKOV3/DDP cells to DDP. First, SKOV3 and SKOV3/DDP cells were treated with 2 μg/mL DDP or 40 μM tasquinimod. Western blot and quantitative real-time polymerase chain reaction (qPCR) were then used to analyze the expression of histone deacetylase 4 (HDAC4), Nur77, Bcl-2 (BH3 domain-specific), and caspase-3. Flow cytometry, scratch-wound assay and immunofluorescence were used to detect apoptosis, migration rate, and related expression of Nur77 and Bcl-2 (BH3 domain-specific). Subsequently, 5×107 SKOV3 or SKOV3/DDP cells cultured with 2 μg/mL DDP were injected into 4-week-old female BALB/c nude mice. Then, the mice were administered 4 mg/kg DDP and 50 mg/kg tasquinimod every 3 days. Finally, the changes in tumor diameter and weight were measured. After treatment of SKOV3 and SKOV3/DDP cells with tasquinimod, cell migration and HDAC4 expression levels were significantly reduced, while Nur77 expression was increased. Tasquinimod treatment enhanced the expression of Nur77 and caspase-3, and cells transfected with si-Nur77 showed the opposite result. Transfection of si-Nur77 reduced the expression of caspase-3 and Nur77 in the SKOV3/DDP cells that were treated with both DDP and tasquinimod. After injection of SKOV3/DDP cells into the mice, the tumor diameter, mass and in vivo HDAC4 level were significantly decreased by tasquinimod. Meanwhile, the levels of Nur77 and Bcl-2 (BH3 domain-specific) were increased. Tasquinimod upregulated the Nur77/Bcl-2 pathway to induce apoptosis in SKOV3/DDP cells and enhanced the anti-tumor effect of DDP in SKOV3/DDP xenografts. Therefore, tasquinimod can be expected to find clinical applications in enhancing DDP resistance.

Gene Expression and Drug Sensitivity Analysis of Mitochondrial Chaperones Reveals That HSPD1 and TRAP1 Expression Correlates with Sensitivity to Inhibitors of DNA Replication and Mitosis.

Mitochondria-critical metabolic hubs in eukaryotic cells-are involved in a wide range of cellular functions, including differentiation, proliferation, and death. Mitochondria import most of their proteins from the cytosol in a linear form, after which they are folded by mitochondrial chaperones. However, despite extensive research, the extent to which the function of particular chaperones is essential for maintaining specific mitochondrial and cellular functions remains unknown. In particular, it is not known whether mitochondrial chaperones influence the sensitivity to drugs used in the treatment of cancers. By mining gene expression and drug sensitivity data for cancer cell lines from publicly available databases, we identified mitochondrial chaperones whose expression is associated with sensitivity to oncology drugs targeting particular cellular pathways in a cancer-type-dependent manner. Importantly, we found the expression of TRAP1 and HSPD1 to be associated with sensitivity to inhibitors of DNA replication and mitosis. We confirmed experimentally that the expression of HSPD1 is associated with an increased sensitivity of ovarian cancer cells to drugs targeting mitosis and a reduced sensitivity to drugs promoting apoptosis. Taken together, our results support a model in which particular mitochondrial pathways hinge upon specific mitochondrial chaperones and provide the basis for understanding selectivity in mitochondrial chaperone-substrate specificity.

Inhibit ALDH3A2 reduce ovarian cancer cells survival via elevating ferroptosis sensitivity

Ovarian cancer (OC) is a malignant gynecologic tumor with high morbidity and mortality. As a newly discovered mode of programmed cell death, ferroptosis has been involved in various pathological processes of kinds of tumors in recent years. Aldehyde dehydrogenase 3 family member A2 (ALDH3A2) catalyzes the oxidation of long-chain aliphatic aldehydes to fatty acid. ALDH3A2 has been shown to be associated with ferroptosis in acute myeloid leukemia (AML), but the mechanism remains unclear. In this study, we analyzed the TCGA and GTEx databases and showed that high ALDH3A2 expression predicted poor prognosis in ovarian cancer. Further studies found that knockout or overexpression of ALDH3A2 correspondingly increased or attenuated the ferroptosis sensitivity of ovarian cancer cells. And sequencing revealed that ALDH3A2 knockout led to the activation of lipid metabolic, GSH metabolic, phospholipid metabolic, and aldehyde metabolic pathways, suggesting that ALDH3A2 induced changes in the sensitivity of ovarian cancer cells to ferroptosis by affecting these metabolic processes. Our results provide a new promising therapeutic strategy for the treatment of OC.

HSP90AB1 as the Druggable Target of Maggot Extract Reverses Cisplatin Resistance in Ovarian Cancer.

Cisplatin resistance is a crucial factor affecting ovarian cancer patient's survival rate, but the primary mechanism underlying cisplatin resistance in ovarian cancer remains unclear, and this prevents the optimal use of cisplatin therapy. Maggot extract (ME) is used in traditional Chinese medicine for patients with comas and patients with gastric cancer when combined with other drug treatments. In this study, we investigated whether ME enhances the sensitivity of ovarian cancer cells to cisplatin. Two ovarian cancer cells-A2780/CDDP and SKOV3/CDDP-were treated with cisplatin and ME in vitro. SKOV3/CDDP cells that stably expressed luciferase were subcutaneously or intraperitoneally injected into BALB/c nude mice to establish a xenograft model, and this was followed by ME/cisplatin treatment. In the presence of cisplatin, ME treatment effectively suppressed the growth and metastasis of cisplatin-resistant ovarian cancer in vivo and in vitro. RNA-sequencing data showed that HSP90AB1 and IGF1R were markedly increased in A2780/CDDP cells. ME treatment markedly decreased the expression of HSP90AB1 and IGF1R, thereby increasing the expression of the proapoptotic proteins p-p53, BAX, and p-H2AX, while the opposite effects were observed for the antiapoptotic protein BCL2. Inhibition of HSP90 ATPase was more beneficial against ovarian cancer in the presence of ME treatment. In turn, HSP90AB1 overexpression effectively inhibited the effect of ME in promoting the increased expression of apoptotic proteins and DNA damage response proteins in SKOV3/CDDP cells. Inhibition of cisplatin-induced apoptosis and DNA damage by HSP90AB1 overexpression confers chemoresistance in ovarian cancer. ME can enhance the sensitivity of ovarian cancer cells to cisplatin toxicity by inhibiting HSP90AB1/IGF1R interactions, and this might represent a novel target for overcoming cisplatin resistance in ovarian cancer chemotherapy.

The characterization of the sensitive ovarian cancer cell lines A2780 and W1 in response to ovarian CAFs

PurposeThe cancer-associated fibroblasts (CAFs) are one of the most abundant components of the tumor microenvironment (TME). CAFs have been implicated in tumor progression, extracellular matrix (ECM) remodeling, and treatment resistance. Drug resistance is the primary limiting factor in achieving cures for patients with cancer, particularly ovarian cancer. Therefore, inhibiting CAFs can be an effective strategies for cancer treatment. In this research, we studied whether CAFs have an influence on drug-sensitive ovarian cancer cells to become more resistant. We examined the influence of CAFs on genes and proteins expression changes in sensitive ovarian cancer cells. We prepared a 3D co-culture to investigate the role of CAFs on cancer cell morphology. MethodsHere, we performed a detailed analysis of drug-sensitive ovarian cancer cell lines (A2780 and W1) and the influence of ovarian CAFs on the A2780 and W1 cells morphology, genes and proteins expression. The 2D and 3D cultures, genes expression analysis (TaqMan qPCR), and proteins expression (Western blot analysis) were assessed in this study. ResultsWe observed upregulation of ABCC5, CYP2C8, CYP2C9, and DHFR mRNA in cell lines supplemented by CAFs medium. We showed fibronectin overexpression and COL3A1 downregulation after supplementation with CAFs. Co-culturing with CAFs prevented the formation of spheroids in 3D conditions. ConclusionWe demonstrated that the process of drug resistance in ovarian cancer cells is launched by CAFs. CAFs not only simulate cancer cells to produce drug transporters and specific enzymes production, but also remodel the TME to increase drug resistance. We believe that cancer progression and migration is due to the CAFs po-tumorigenic activity.