Cisplatin-resistant Ovarian Cancer Cells Research Articles

Synthesis, Chemical Characterization, and Biological Evaluation of Hydrophilic Gold(I) and Silver(I) N-Heterocyclic Carbenes as Potential Anticancer Agents.

A series of new gold(I) and silver(I) N-heterocyclic carbenes bearing a 1-thio-β-d-glucose tetraacetate moiety was synthesized and chemically characterized. The compounds' stability and solubility in physiological conditions were investigated employing a multitechnique approach. Interaction studies with biologically relevant proteins, such as superoxide dismutase (SOD) and human serum albumin (HSA), were conducted via UV-vis absorption spectroscopy and high-resolution ESI mass spectrometry. The biological activity of the compounds was evaluated in the A2780 and A2780R (cisplatin-resistant) ovarian cancer cell lines and the HSkMC (human skeletal muscle) healthy cell line. Inhibition studies of the selenoenzyme thioredoxin reductase (TrxR) were also carried out. The results highlighted that the gold complexes are more stable in aqueous environment and capable of interaction with SOD and HSA. Moreover, these carbenes strongly inhibited the TrxR activity. In contrast, the silver ones underwent structural alterations in the aqueous medium and showed greater antiproliferative activity.

Zinc finger domain of p62/SQSTM1 is involved in the necroptosis of human cisplatin‑resistant ovarian cancer cells treated with sulfasalazine.

Cisplatin resistance in ovarian cancer cells is mainly apoptosis resistant. Although other types of programmed cell death are highly involved in chemoresistance, which type can overcome cisplatin resistance remains unclear. The present study observed that cisplatin-sensitive SKOV3 cells and cisplatin-resistant SKOV3/DDP cells had different levels of sensitivity to sulfasalazine (SAS). The present study aimed to investigate the effect of SAS on necroptosis under the same inhibition rate in these two types of cells. Necroptosis inhibitor Necrostatin-1 (Nec-1) attenuated SAS-induced SKOV3/DDP cytotoxicity. SAS decreased SKOV3/DDP cells survival rate, accompanied by decreased cell adhesion and spreading. SAS treatment activated necrosome formation in SKOV3/DDP cells, suggesting the possibility of necroptosis. p62/sequestosome-1 (SQSTM1) protein expression levels were also increased over the same time period. The transfection of small interfering (si)-p62 could decrease the ratios of phosphorylated (p)-receptor-interacting serine/threonine kinase 1 (RIP1)/RIP1, p-receptor-interacting serine/threonine kinase 3 (RIP3)/RIP3 and p-mixed lineage kinase domain-like protein (MLKL)/MLKL proteins in SKOV3/DDP cells. Under the si-p62 condition, there was no increase in the rate of cell survival in Nec-1 and SAS combination group compared with SAS. The zinc finger domain deletion of p62/SQSTM1 effectively decreased the expression levels of necroptosis-related p-proteins. Collectively, certain drugs were able to induce necroptosis in SKOV3/DDP, while p62/RIP1/RIP3/MLKL was associated with the induction of necroptosis and with increasing the sensitivity of cisplatin-resistant ovarian cancer cells, which provided evidence for potential as a therapeutic target for overcoming resistance.

Salvia microphylla essential oil reduces cell viability in cisplatin-resistant clear cell type ovarian cancer cells caused by mitochondrial dysfunction

Salvia microphylla essential oil reduces cell viability in cisplatin-resistant clear cell type ovarian cancer cells caused by mitochondrial dysfunction

MUL1 identified as mitochondria-linked biomarker promoting cisplatin resistance in OC cells

Ovarian cancer (OC) ranks among the prevalent tumors affecting the female reproductive system. The aim of this study was to evaluate mitochondria-associated platinum resistance genes using organoid models. Univariate Cox regression, LASSO and multivariate Cox regression analyses were performed on The Cancer Genome Atlas (TCGA) database to construct 2-gene prognostic signature (MUL1 and SSBP1), and GSE26712 dataset was used for external validation. In addition, the relationship between MUL1 and platinum resistance was examined by organoid culture, lentiviral transduction, CCK8 assay, and Western blot. The results showed that patients in the high-risk group exhibited significantly worse OS (P = 0.002, P = 0.017). Drug sensitivity analysis revealed that platinum resistance increased with the upregulation of MUL1 expression (Cor = 0.5154, P = 0.02). Our experimental findings demonstrated that knockout of the MUL1 gene significantly increased apoptosis and enhanced the sensitivity of the OC cell line A2780 to cisplatin. Through this study, we have provided strong evidence for further research on prognostic risk factors and individualized treatment in OC patients, and provided new insights into addressing platinum resistance in OC.

Circular RNA circ_ARHGEF28 inhibits MST1/2 dimerization to suppress Hippo pathway to induce cisplatin resistance in ovarian cancer

BackgroundCisplatin is integral to ovarian cancer treatment, yet resistance to this drug often results in adverse patient outcomes. The association of circular RNA (circRNA) with cisplatin resistance in ovarian cancer has been observed, but the mechanisms governing this relationship require further elucidation.MethodsHigh-throughput sequencing was utilized to profile circRNA expression in cisplatin-resistant ovarian cancer cells. Gain-and-loss-of-function experiments assessed the impact on cisplatin sensitivity, both in vitro and in vivo. Fluorescence in situ hybridization was conducted to determine the cellular distribution of circRNAs, and RNA pulldown and immunoprecipitation experiments were performed to identify associated binding proteins.ResultsThe study revealed that circ_ARHGEF28 is overexpressed in certain cisplatin-resistant ovarian cancer tissues and cell lines, and is associated with reduced progression-free survival in patients. It was observed that circ_ARHGEF28 contributes to cisplatin resistance in ovarian cancer models, both in vitro and in vivo. Importantly, circ_ARHGEF28 was found to interact directly with MST1/2, inhibiting the SARAH coiled-coil binding domains and consequently deactivating the Hippo pathway.ConclusionThis investigation identifies circ_ARHGEF28 as a novel circRNA that contributes to cisplatin resistance in ovarian cancer by suppressing the Hippo pathway. Therapeutic strategies targeting circ_ARHGEF28 may offer a potential avenue to mitigate cisplatin resistance in ovarian cancer treatment.

The Induction of G2/M Phase Cell Cycle Arrest and Apoptosis by the Chalcone Derivative 1C in Sensitive and Resistant Ovarian Cancer Cells Is Associated with ROS Generation.

Ovarian cancer ranks among the most severe forms of cancer affecting the female reproductive organs, posing a significant clinical challenge primarily due to the development of resistance to conventional therapies. This study investigated the effects of the chalcone derivative 1C on sensitive (A2780) and cisplatin-resistant (A2780cis) ovarian cancer cell lines. Our findings revealed that 1C suppressed cell viability, induced cell cycle arrest at the G2/M phase, and triggered apoptosis in both cell lines. These effects are closely associated with generating reactive oxygen species (ROS). Mechanistically, 1C induced DNA damage, modulated the activity of p21, PCNA, and phosphorylation of Rb and Bad proteins, as well as cleaved PARP. Moreover, it modulated Akt, Erk1/2, and NF-κB signaling pathways. Interestingly, we observed differential effects of 1C on Nrf2 levels between sensitive and resistant cells. While 1C increased Nrf2 levels in sensitive cells after 12 h and decreased them after 48 h, the opposite effect was observed in resistant cells. Notably, most of these effects were suppressed by the potent antioxidant N-acetylcysteine (NAC), underscoring the crucial role of ROS in 1C-induced antiproliferative activity. Moreover, we suggest that modulation of Nrf2 levels can, at least partially, contribute to the antiproliferative effect of chalcone 1C.

Ruthenium(II) complexes of curcumin and β-diketone derivatives: effect of structural modifications on their cytotoxicity.

Ruthenium(II) complexes (Ru1-Ru3) with the general formula [Ru(O-O)(PPh3)2(bipy)]PF6, bearing two triphenylphosphine (PPh3), bipyridine (bipy) and a series of natural and synthetic β-diketones (O,O) ligands were synthesized and characterized using various analytical techniques. The interaction between the complexes and calf thymus DNA (CT-DNA) was investigated and demonstrated a weak interaction. The cytotoxicity of the complexes was investigated against breast cancer cells (MDA-MB-231 and MCF-7), lung cancer cells (A549), cisplatin-resistant ovarian cancer cells (A2780cis), as well as non-tumour lung (MRC-5) and non-tumour breast (MCF-10A) cell lines. All complexes exhibited cytotoxic activity against all the cell lines studied, with half maximal inhibitory concentration (IC50) values ranging from 0.39 to 13 µM. Notably, the three complexes demonstrated selectivity against the A2780cis cell line, with IC50 ranging from 0.39 to 0.82 µM. Among them, Ru2 exhibited the highest cytotoxicity, with an IC50 value of 0.39 µM. Consequently, this new class of complexes shows good selectivity towards cisplatin-resistant ovarian cancer cells and it is promising for further investigation as anti-cancer agents.

Blocking Oncostatin M receptor abrogates STAT3 mediated integrin signaling and overcomes chemoresistance in ovarian cancer

Chemotherapy such as cisplatin is widely used to treat ovarian cancer either before or after surgical debulking. However, cancer relapse due to chemotherapy resistance is a major challenge in the treatment of ovarian cancer. The underlying mechanisms related to chemotherapy resistance remain largely unclear. Therefore, identification of effective therapeutic strategies is urgently needed to overcome therapy resistance. Transcriptome-based analysis, in vitro studies and functional assays identified that cisplatin-resistant ovarian cancer cells express high levels of OSMR compared to cisplatin sensitive cells. Furthermore, OSMR expression associated with a module of integrin family genes and predominantly linked with integrin αV (ITGAV) and integrin β3 (ITGB3) for cisplatin resistance. Using ectopic expression and knockdown approaches, we proved that OSMR directly regulates ITGAV and ITGB3 gene expression through STAT3 activation. Notably, targeting OSMR using anti-OSMR human antibody inhibited the growth and metastasis of ovarian cancer cells and sensitized cisplatin treatment. Taken together, our results underscore the pivotal role of OSMR as a requirement for cisplatin resistance in ovarian cancer. Notably, OSMR fostered the expression of a distinct set of integrin genes, which in turn resulted into a crosstalk between OSMR and integrins for signaling activation that is critical for cisplatin resistance. Therefore, targeting OSMR emerges as a promising and viable strategy to reverse cisplatin-resistance in ovarian cancer.

TGF β1 promotes the polarization of M2-type macrophages and activates PI3K/mTOR signaling pathway by inhibiting ISG20 to sensitize ovarian cancer to cisplatin

The involvement of Interferon-stimulated exonuclease gene 20 (ISG20) has been reported in renal clear cell carcinoma, hepatocellular carcinoma, and cervical cancer. However, its role in ovarian cancer chemotherapy remains unclear. In this study, we conducted a comparative analysis of TGF-β1 and ISG20 in cisplatin-sensitive and cisplatin-resistant ovarian cancer cells and tissues using qRT-PCR and a tissue immunofluorescence analysis. We also investigated the impact of ISG20-targeted drugs (IFN-γ) and TGF-β1 inhibitors on cisplatin response both in vivo and in vitro. Additionally, we assessed the effects of TGF-β1 or ISG20 on the polarization of tumor-associated macrophages through flow cytometry and ELISA analysis. Our findings revealed that ISG20 expression was lower in cisplatin-resistant tissues compared to cisplatin-sensitive tissues; however, overexpression of ISG20 sensitized ovarian cancer to cisplatin treatment. Furthermore, activation of ISG20 expression with IFN-γ or TGF-β1 inhibitors enhanced the sensitivity of ovarian cancer cells to cisplatin therapy. Notably, our results demonstrated that TGF-β1 promoted M2-type macrophage polarization as well as PI3K/mTOR pathway activation by suppressing ISG20 expression both in vivo and in vitro. In conclusion, our study highlights the critical role played by ISG20 within the network underlying cisplatin resistance in ovarian cancer. Targeting ISG20 using IFN-γ or TGF-β1 inhibitors may represent a promising therapeutic strategy for treating ovarian cancer.

Proto-oncogene c-Myb potentiates cisplatin resistance of ovarian cancer cells by downregulating lncRNA NKILA and modulating cancer stemness and LIN28A-let7 axis

Ovarian cancer is a major gynecological cancer that has poor prognosis associated mainly to its late diagnosis. Cisplatin is an FDA approved ovarian cancer therapy and even though the therapy is initially promising, the patients mostly progress to resistance against cisplatin. The underlying mechanisms are complex and not very clearly understood. Using two different paired cell lines representing cisplatin-sensitive and the cisplatin-resistant ovarian cancer cells, the ES2 and the A2780 parental and cisplatin-resistant cells, we show an elevated proto-oncogene c-Myb in resistant cells. We further show down-regulated lncRNA NKILA in resistant cells with its de-repression in resistant cells when c-Myb is silenced. NKILA negatively correlates with cancer cell and invasion but has no effect on cellular proliferation or cell cycle. C-Myb activates NF-κB signaling which is inhibited by NKILA. The cisplatin resistant cells are also marked by upregulated stem cell markers, particularly LIN28A and OCT4, and downregulated LIN28A-targeted let-7 family miRNAs. Whereas LIN28A and downregulated let-7s individually de-repress c-Myb-mediated cisplatin resistance, the ectopic expression of let-7s attenuates LIN28A effects, thus underlying a c-Myb-NKILA-LIN28A-let-7 axis in cisplatin resistance of ovarian cancer cells that needs to be further explored for therapeutic intervention.

P27Kip1 and cytoplasmic pSer10p27 are promising biomarkers for predicting prognosis and chemotherapy response in ovarian cancer.

The biological function of p27Kip1 largely depends on its subcellular localization and phosphorylation status. Different subcellular localizations and phosphorylation statuses of p27Kip1 may represent distinct clinical values, which are unclear in ovarian cancer. This study aimed to elucidate different subcellular localizations of p27Kip1 and pSer10p27 in predicting prognosis and chemotherapy response in ovarian cancer. Meta-analyses were executed to evaluate the association of p27Kip1 and phosphorylated p27Kip1 with the prognosis of ovarian cancer patients. The expression levels and patterns of p27Kip1 and pSer10p27 were evaluated by immunohistochemistry. The correlations between different p27Kip1 states, clinicopathological features, and prognosis were analyzed. p27Kip1 and pSer10p27 expression levels in cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines were detected using WB. KEGG analysis and WB were performed to evaluate the pathways in which p27Kip1 was involved. Meta-analyses showed that p27Kip1 was associated with significantly better overall survival (OS) in ovarian cancer (HR=2.14; 95% CI [1.71-2.68]) and pSer10p27 was associated with significantly poor OS in mixed solid tumors (HR=2.56; 95% CI [1.76-3.73]). In our cohort of ovarian cancer patients, low total p27Kip1 remained independent risk factors of OS (HR=2.097; 95% CI [1.121-3.922], P=0.021) and PFS (HR=2.483; 95% CI [1.364-4.518], P=0.003), while low cytoplasmic pSer10p27 had independent protective effects in terms of OS (HR=0.472; 95% CI [0.248-0.898], P=0.022) and PFS (HR=0.488; 95% CI [0.261-0.910], P=0.024). Patients with low total p27Kip1/pSer10p27 and low nuclear p27Kip1 had worse chemotherapy responses, while patients with low cytoplasmic pSer10p27 expression had better chemotherapy responses. The protein levels of p27Kip1 and pSer10p27 were significantly reduced in the cisplatin-resistant cell lines SKOV3-cDDP and A2780-cDDP, and the level of p27Kip1/pSer10p27 was subjective to Akt activation. The present study demonstrates that p27Kip1 and cytoplasmic pSer10p27 are promising biomarkers for predicting prognosis and chemotherapy response in ovarian cancer.

Angelica sinensis polysaccharide combined with cisplatin reverses cisplatin resistance of ovarian cancer by inducing ferroptosis via regulating GPX4

Cisplatin (DDP) resistance poses a significant challenge in the treatment of ovarian cancer. Studies have shown that the combination of certain polysaccharides derived from plants with DDP is an effective approach to overcoming drug resistance in some cancers. Angelica sinensis (Oliv.) Diels has been used for centuries in China to treat gynecological ailments. Numerous studies indicate that Angelica sinensis polysaccharide (ASP), an extract from Angelica sinensis, can inhibit various forms of cancer. However, the impact of ASP on ovarian cancer remains unexplored. Through both in vitro and in vivo experiments, our study revealed the capability of ASP to effectively reversing DDP resistance in cisplatin-resistant ovarian cancer cells, while exhibiting acceptable safety profiles in vivo. To elucidate the mechanism underlying drug resistance reversal, we employed RNA-seq analysis and identified GPX4 as a key gene. Considering the role of GPX4 in ferroptosis, we conducted additional research to explore the effects of combining ASP with DDP on SKOV3/DDP cells. In summary, our findings demonstrate that the combination of ASP and DDP effectively suppresses GPX4 expression in SKOV3/DDP cells, thereby reversing their resistance to DDP.

Exploring the Antiproliferative and Modulatory Effects of 1-Methoxyisobrassinin on Ovarian Cancer Cells: Insights into Cell Cycle Regulation, Apoptosis, Autophagy, and Its Interactions with NAC.

Ovarian cancer, a highly lethal malignancy among reproductive organ cancers, poses a significant challenge with its high mortality rate, particularly in advanced-stage cases resistant to platinum-based chemotherapy. This study explores the potential therapeutic efficacy of 1-methoxyisobrassinin (MB-591), a derivative of indole phytoalexins found in Cruciferae family plants, on both cisplatin-sensitive (A2780) and cisplatin-resistant ovarian cancer cells (A2780 cis). The findings reveal that MB-591 exhibits an antiproliferative effect on both cell lines, with significantly increased potency against cisplatin-sensitive cells. The substance induces alterations in the distribution of the cell cycle, particularly in the S and G2/M phases, accompanied by changes in key regulatory proteins. Moreover, MB-591 triggers apoptosis in both cell lines, involving caspase-9 cleavage, PARP cleavage induction, and DNA damage, accompanied by the generation of reactive oxygen species (ROS) and mitochondrial dysfunction. Notably, the substance selectively induces autophagy in cisplatin-resistant cells, suggesting potential targeted therapeutic applications. The study further explores the interplay between MB-591 and antioxidant N-acetylcysteine (NAC), in modulating cellular processes. NAC demonstrates a protective effect against MB-591-induced cytotoxicity, affecting cell cycle distribution and apoptosis-related proteins. Additionally, NAC exhibits inhibitory effects on autophagy initiation in cisplatin-resistant cells, suggesting its potential role in overcoming resistance mechanisms.

Abstract 2989: MicroRNA profiling in human samples and cell lines uncovers eight key players in the cisplain resistance of HGSOC

Abstract Metastasis and drug resistance remain significant contributors to cancer-related mortality globally. In ovarian cancer, a substantial 70% of cases develop resistance to the front-line therapy, cisplatin. Despite numerous proposed mechanisms for cisplatin resistance, the complete molecular events leading to this phenomenon in ovarian cancer remain incompletely understood. Mounting evidence suggests that dysregulation of microRNAs (miRNAs) plays a pivotal role in carcinogenesis, including the development of drug resistance. While various miRNAs have been identified in ovarian cancer samples and cell lines, few studies have compared miRNA expression in human paraffin ovarian samples and cisplatin-resistant high-grade serous ovarian cancer (HGSOC), the most prevalent and malignant of gynecological malignancies. This study aimed to identify key miRNAs implicated in cisplatin resistance. We performed miRNA expression profiles in RNA isolated from human paraffin ovarian tumors and ovarian cancers cell lines. Eight miRNAs were commonly increased in paraffin samples and cisplatin resistant ovarian cancer cells. Targeting these miRNAs with inhibitors significantly reduced cell proliferation by more than 50% for miR-203a, miR-96-5p, miR-10a-5p, miR-141-3p, miR-200c-3p, and miR-182-5p, and to a lesser extent, miR-296-5p and miR-1206. Inhibitors demonstrated a reduction in cell migration for all targets except miR-200c-3p and miR-10a-5p. Analysis of online databases, literature reports, and molecular pathway construction revealed that these eight miRNAs regulate key molecular pathways associated with cell proliferation, primarily through PTEN regulation in cisplatin-resistant HGSOC cells. Interrogation of the KM plotter patient database revealed that high expression of miR-1206, miR-10a, miR-141, and miR-96 correlates with a poor prognosis in ovarian cancer patients. These findings position these eight miRNAs as potential therapeutic targets and markers for cisplatin response in ovarian cancer therapy. Citation Format: Mariela Rivera-Serrano, Marienid Flores, Jose Rolon, Victor Reyes, Fatma Valiyeva, Pablo E. Vivas-Mejia. MicroRNA profiling in human samples and cell lines uncovers eight key players in the cisplain resistance of HGSOC [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 2989.

Abstract 5860: Understanding the biological role of MMP16 in cisplatin resistance in ovarian cancer

Abstract High-Grade Serous Ovarian Cancer (HGSOC) is the most common and lethal of Ovarian Cancer (OC) types, which accounts for eighty percent of deaths. Treatment for OC includes surgery and platinum-based therapy. However, around 70% of women with HGSOC become resistant to chemotherapy. Therefore, new therapeutic agents with higher specificity and efficacy are needed for women with advanced and drug-resistant OC. Matrix metalloproteases (MMPs) are a group of enzymes involved in the degradation of the extracellular matrix (ECM). Deregulation of MMPs contributes to tumor growth and metastasis in several cancer types. Preliminary studies of our research team found that MMP16 is higher in cisplatin-resistant as compared with cisplatin-sensitive OC cells. The aim of this project is to understand the role of MMP16 in the cisplatin resistance of OC cells. We hypothesize that MMP16 increased expression may contribute to cancer progression and drug-resistance. We performed experiments in A2780/A2780CP20 and OVCAR3/OVCAR3CIS human OC cells. To assess the MMP16 protein levels we used western blot analysis. To measure the mRNA levels, we used qRT-PCR. Kaplan-Meier survival curves were generated by interrogation of the KM Plotter patient database. The MMP16 protein and qRT-PCR experiments confirmed that protein and mRNA levels are more abundant in cisplatin-resistant as compared with cisplatin-sensitive cells. Interrogation of the KM plotter database showed that OC patients with higher MMP16 mRNA levels live less as compared with OC patients with lower MMP16 levels. Ongoing experiments are testing the biological effect of small interference RNA (siRNA) targeting MMP16 in cisplatin-resistant OC cells. Citation Format: Jesennia Bonilla-Liriano, Mariela Rivera-Serrano, Victor Reyes-Burgos, Jose Rolon-Perez, Fatima Valiyeva, Pablo Vivas-Mejia. Understanding the biological role of MMP16 in cisplatin resistance in ovarian cancer [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 5860.

Abstract 4473: Targeting matrix metalloproteinase-3 (MMP-3) in high-grade serous ovarian cancer

Abstract High-Grade Serous Ovarian Cancer (HGSOC) is the most aggressive and lethal gynecological malignancy. Surgery and chemotherapy (with platinum compounds) are the main treatments. Many patients relapse and develop chemotherapy resistance, limiting the therapeutic utility of these therapies. This persistent resistance makes HGSOC treatment difficult. Cisplatin-resistant ovarian cancer cells upregulate Matrix Metalloproteinase-3. MMP3 is an enzyme involved in active tissue remodeling and extracellular matrix protein breakdown during dynamic physiological processes. The structure of MMP3 includes the prodomain, the catalytic domain and the hemopexin domain. We showed that MMP3 protein levels are higher in cisplatin resistant as compared with cisplatin sensitive HGSOC cells. Our research team showed that small interference RNA (siRNA)-mediated MMP3 knockdown reduced cisplatin-resistant ovarian cancer cell growth and invasion. This data indicates that MMP3 may be a promising HGSOC treatment target. Targeting MMP3 with small chemical inhibitors (SCI) could represent a better option than siRNA because SCI are more stable and easier to deliver. The purpose of this project is to design SCI of MMP3 in the propeptide, catalytic, and hemopexin domains of MMP3. We used in silico methods to identify MMP3 inhibitors in these domains. The ZINC20 database of commercially compounds was used for virtual screening using Python Prescription (PyRx) software. We identified 25 ligands out of 370,000 with the greatest affinity for each MMP3 functional domains. SwissADME was then used to evaluate in silico absorption, distribution, metabolism, pharmacokinetics, drug-likeliness, and medicinal chemistry. This research lays the groundwork for HGSOC therapeutic strategies to improve treatment efficacy, especially for chemotherapy-resistant patients. Citation Format: Víctor G. Reyes-Burgos, Eliud Hernández-O'Farrill, Luis E. Vazquez Quiñones, Marienid Flores-Colón, Fatima Valiyeva, Pablo E. Vivas-Mejía. Targeting matrix metalloproteinase-3 (MMP-3) in high-grade serous ovarian cancer [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 4473.

HIF-2α-dependent TGFBI promotes ovarian cancer chemoresistance by activating PI3K/Akt pathway to inhibit apoptosis and facilitate DNA repair process

Hypoxia-mediated chemoresistance plays a crucial role in the development of ovarian cancer (OC). However, the roles of hypoxia-related genes (HRGs) in chemoresistance and prognosis prediction and theirs underlying mechanisms remain to be further elucidated. We intended to identify and validate classifiers of hub HRGs for chemoresistance, diagnosis, prognosis as well as immune microenvironment of OC, and to explore the function of the most crucial HRG in the development of the malignant phenotypes. The RNA expression and clinical data of HRGs were systematically evaluated in OC training group. Univariate and multivariate Cox regression analysis were applied to construct hub HRGs classifiers for prognosis and diagnosis assessment. The relationship between classifiers and chemotherapy response and underlying pathways were detected by GSEA, CellMiner and CIBERSORT algorithm, respectively. OC cells were cultured under hypoxia or transfected with HIF-1α or HIF-2α plasmids, and the transcription levels of TGFBI were assessed by quantitative PCR. TGFBI was knocked down by siRNAs in OC cells, CCK8 and in vitro migration and invasion assays were performed to examine the changes in cell proliferation, motility and metastasis. The difference in TGFBI expression was examined between cisplatin-sensitive and -resistant cells, and the effects of TGFBI interference on cell apoptosis, DNA repair and key signaling molecules of cisplatin-resistant OC cells were explored. A total of 179 candidate HRGs were extracted and enrolled into univariate and multivariate Cox regression analysis. Six hub genes (TGFBI, CDKN1B, AKAP12, GPC1, TGM2 and ANGPTL4) were selected to create a HRGs prognosis classifier and four genes (TGFBI, AKAP12, GPC1 and TGM2) were selected to construct diagnosis classifiers. The HRGs prognosis classifier could precisely distinguish OC patients into high-risk and low-risk groups and estimate their clinical outcomes. Furthermore, the high-risk group had higher percentage of Macrophages M2 and exhibited higher expression of immunecheckpoints such as PD-L2. Additionally, the diagnosis classifiers could accurately distinguish OC from normal samples. TGFBI was further verified as a specific key target and demonstrated that its high expression was closely correlated with poor prognosis and chemoresistance of OC. Hypoxia upregulated the expression level of TGFBI. The hypoxia-induced factor HIF-2α but not HIF-1α could directly bind to the promoter region of TGFBI, and facilitate its transcription level. TGFBI was upregulated in cisplatin-sensitive and resistant ovarian cancer cells in a cisplatin time-dependent manner. TGFBI interference downregulated DNA repair-related markers (p-p95/NBS1, RAD51, p-DNA-PKcs, DNA Ligase IV and Artemis), apoptosis-related marker (BCL2) and PI3K/Akt pathway-related markers (PI3K-p110 and p-Akt) in cisplatin-resistant OC cells. In summary, the HRGs prognosis risk classifier could be served as a predictor for OC prognosis and efficacy evaluation. TGFBI, upregulated by HIF-2α as an HRG, promoted OC chemoresistance through activating PI3K/Akt pathway to reduce apoptosis and enhance DNA damage repair pathway.

TMCO1 regulates cell proliferation, metastasis and EMT signaling through CALR, promoting ovarian cancer progression and cisplatin resistance.

This study aimed to explore the involvement of Transmembrane and coiled-coil domains 1 (TMCO1) in ovarian cancer progression and its regulatory mechanisms in cisplatin resistance. Using the GEPIA database, we analyzed TMCO1 expression in ovarian cancer and normal tissues. In a cohort of 99 ovarian cancer patients, immunohistochemistry and immunofluorescence were employed to assess TMCO1 expression in tumor and adjacent tissues, correlating findings with clinical and pathological characteristics. TMCO1 overexpression and knockout cell models were constructed, and their impact on non-cisplatin-resistant (SK-OV-3) and cisplatin-resistant (SK-OV-3-CDDP) ovarian cancer cells was investigated through cloning, wound healing, Fluo 4, and Transwell experiments. Knocking down CALR and VDAC1 was performed to examine their effects on TMCO1, cell proliferation, and malignant markers. Subcutaneous tumor models in nude mice elucidated the in vivo role of TMCO1 in tumor growth. Expression levels of CALR, VDAC1, angiogenesis indicators (CD34), and epithelial-mesenchymal transition (EMT) markers were evaluated. TMCO1 expression in ovarian cancer tissue significantly differed from normal tissue, correlating with survival rates. TMCO1 overexpression was associated with lymph node metastases, late FIGO stage, and larger tumors. TMCO1 promoted proliferation, calcium ion elevation, cytoskeletal remodeling, and metastasis in SK-OV-3 and SK-OV-3-CDDP cells, upregulating VDAC1, CALR, Vimentin, N-cadherin, β-catenin, and downregulating E-cadherin. Silencing TMCO1 inhibited cell growth, proliferation, and angiogenesis in vivo, suppressing the expression of CALR, VDAC1, Vimentin, N-cadherin, and β-catenin. Overall, this study highlighted TMCO1 as a crucial regulator in ovarian cancer progression, influencing VDAC1 through CALR and impacting diverse cellular processes, offering potential as a targeted therapeutic strategy for ovarian cancer.

HMGB1 enhances the migratory and invasive abilities of A2780/DDP cells by facilitating epithelial to mesenchymal transition via GSK‑3β.

The aim of the present study was to investigate the impact and mechanism of high mobility group box 1 (HMGB1) on the regulation of cell migration and invasion in A2780/DDP cisplatin-resistant ovarian cancer cells. After transfecting small interfering (si)RNA-HMGB1 into A2780/DDP cells, Transwell migration and invasion assays were conducted to assess alterations in the cell migratory and invasive abilities. Additionally, western blotting analyses were performed to examine changes in HMGB1, phosphorylated (p)-GSK-3β, GSK-3β, E-cadherin and vimentin expression levels. The results of the present study demonstrated that the migratory and invasive abilities of A2780/DDP cells were significantly higher compared with those of A2780 cells. Additionally, the expression levels of HMGB1, p-GSK-3β and the mesenchymal phenotype marker, vimentin, in A2780/DDP cells were significantly elevated relative to the levels in A2780 cells. Conversely, the expression level of the epithelial phenotype marker, E-cadherin, was markedly decreased compared with that in A2780 cells. Following transfection of A2780/DDP cells with siRNA-HMGB1, there was a significant reduction in the rate of cell migration and invasion. Simultaneously, the expression levels of HMGB1, p-GSK-3β and vimentin were downregulated while the level of E-cadherin was upregulated. It was therefore concluded that the high expression of HMGB1 in A2780/DDP cells enhanced the cell migration and invasion abilities by facilitating epithelial to mesenchymal transition via GSK-3β.

Modulation of Cisplatin Sensitivity through TRPML1-Mediated Lysosomal Exocytosis in Ovarian Cancer Cells: A Comprehensive Metabolomic Approach.

The lysosome has emerged as a promising target for overcoming chemoresistance, owing to its role in facilitating the lysosomal sequestration of drugs. The lysosomal calcium channel TRPML1 not only influences lysosomal biogenesis but also coordinates both endocytosis and exocytosis. This study explored the modulation of cisplatin sensitivity by regulating TRPML1-mediated lysosomal exocytosis and identified the metabolomic profile altered by TRPML1 inhibition. We used four types of ovarian cancer cells: two cancer cell lines (OVCAR8 and TOV21G) and two patient-derived ovarian cancer cells. Metabolomic analyses were conducted to identify altered metabolites by TRPML1 inhibition. Lysosomal exocytosis in response to cisplatin was observed in resistant cancer cells, whereas the phenomenon was absent in sensitive cancer cells. Through the pharmacological intervention of TRPML1, lysosomal exocytosis was interrupted, leading to the sensitization of resistant cancer cells to cisplatin treatment. To assess the impact of lysosomal exocytosis on chemoresistance, we conducted an untargeted metabolomic analysis on cisplatin-resistant ovarian cancer cells with TRPML1 inhibition. Among the 1446 differentially identified metabolites, we focused on 84 significant metabolites. Metabolite set analysis revealed their involvement in diverse pathways. These findings collectively have the potential to enhance our understanding of the interplay between lysosomal exocytosis and chemoresistance, providing valuable insights for the development of innovative therapeutic strategies.