Target In Epithelial Ovarian Cancer Research Articles

Germ cell-specific gene 2 accelerates cell cycle in epithelial ovarian cancer by inhibiting GSK3α-p27 cascade

Epithelial ovarian cancer (EOC) is one of the most common malignant gynecological tumors with rapid growth potential and poor prognosis, however, the molecular mechanism underlying its outgrowth remained elusive. Germ cell-specific gene 2 (GSG2) was previously reported to be highly expressed in ovarian cancer and was essential for the growth of EOC. In this study, GSG2-knockdown cells and GSG2-overexpress cells were established through lentivirus-mediated transfection with Human ovarian cancer cells HO8910 and SKOV3. Knockdown of GSG2 inhibited cell proliferation and induced G2/M phase arrest in EOC. Interestingly, the expression of p27, a well-known regulator of the cell cycle showed a most significant increase after GSG2 knockdown. Further phosphorylation-protein array demonstrated the phosphorylation of GSK3αSer21 decreased in GSG2-knockdown cells to the most extent. Notably, inhibiting GSK3α activity effectively rescued GSG2 knockdown’s suppression on cell cycle as well as p27 expression in EOC. Our study substantiates that GSG2 is able to phosphorylate GSK3α at Ser21 and then leads to the reduction of p27 expression, resulting in cell cycle acceleration and cell proliferation promotion. Thus, GSG2 may have the potential to become a promising target in EOC.

Effect of tumor type on response to adjuvant platinum-based chemotherapy and prognosis in patients with stage II-IV epithelial ovarian carcinoma.

To evaluate the effect of histological subtype on oncological outcome and adjuvant platinum-based chemotherapy response in patients with epithelial ovarian cancer (EOC). The study group was created with stage II-IV EOC patients. Progression-free survival (PFS) and disease-specific survival (DSS) estimates were determined by using the Kaplan-Meier method. The log-rank test and cox proportional hazards model were performed. A total 396 patients were included the study. Tumor type was serous in 332 (83.8%). Two hundred and thirty-one patients (58.3%) had maximal cytoreduction. Three hundred and twenty-seven (82.6%) patients received complete clinical response. Refractory disease was present in 69 (17.4%) patients. In patients with complete clinical response, 183 (56%) patients recurred. Five-year PFS was 32% in serous group and 31% in non-serous group (p = 0.755). Five-year DSS was 78% in serous group and 87% in non-serous group (p = 0.084). On multivariate analysis, recurrence rates 1.959 times (95% CI: 1.224-3.085; p = 0.004), death rates 2.624 times (95% CI: 1.328-5.185; p = 0.005) higher in patients with optimal cytoreduction than patients with maximal cytoreduction, respectively. Although the rate of maximal cytoreduction was higher in patients with non-serous tumor type, the rate of refractory disease was higher after adjuvant chemotherapy. However, the recurrence rate was higher in serous tumor type. Survival rates were similar in serous and non-serous tumor types. Maximal cytoreduction was an independent predictor factor for survival. Maximal cytoreduction should be the main target in EOC.

Suppression of NBS1 Upregulates CyclinB to Induce Olaparib Sensitivity in Ovarian Cancer.

Background: Deficiencies in DNA damage repair responses promote chemotherapy sensitivity of tumor cells. The Nibrin homolog encoding gene Nijmegen Breakage Syndrome 1 (NBS1) is a crucial component of the MRE11-RAD50-NBN complex (MRN complex) and is involved in the response to DNA double-strand breaks (DSBs) repair that has emerged as an attractive strategy to overcome tumor drug resistance, but the functional relationship between NBS1 regulated DNA damage repair and cell cycle checkpoints has not been fully elucidated. Methods: In this study, lentivirus-mediated RNAi was used to construct NBS1-downregulated cells. Flow cytometry, qPCR, and immunohistochemistry were used to explore the regulatory relationship between NBS1 and CyclinB in vivo and in vitro. Results: Our findings suggest that NBS1 deficiency leads to defective homologous recombination repair. Inhibition of NBS1 expression activates CHK1 and CyclinB signaling pathways leading to cell cycle arrest and sensitizes ovarian cancer cells to Olaparib treatment in vitro and in vivo. NBS1-deficient ovarian cancer cells tend to maintain sensitivity to chemotherapeutic drugs through activation of cell cycle checkpoints. Conclusions: NBS1 may be a potential therapeutic target for epithelial ovarian cancer as it plays a role in the regulation of the DNA damage response and cell cycle checkpoints. Suppression of NBS1 upregulates CyclinB to induce Olaparib sensitivity in ovarian cancer.

Ascitic autotaxin as a potential prognostic, diagnostic, and therapeutic target for epithelial ovarian cancer

BackgroundMalignant ascites contributes to the metastatic process by facilitating the multifocal dissemination of ovarian tumour cells onto the peritoneal surface. However, the prognostic and diagnostic relevance of ascitic fluid remains largely unknown. Herein, we investigated the potential clinical value and therapeutic utility of ascitic autotaxin (ATX) in epithelial ovarian cancer (EOC).MethodsATX expression was assessed in clinical samples. Spheroid-forming assay, real-time PCR, western blot analysis, invadopodia assay, and adhesion assays were performed.ResultsAscitic ATX expression was highly elevated in patients with ovarian cancer compared to those with benign ascites and was associated with advanced stage, high grade, and a short disease-free period in patients with EOC. Combining the diagnostic ability of ascitic ATX and serum CA-125 levels significantly improved the area under the curve (AUC) value for EOC compared to serum CA125 level alone. This marker combination showed a large odds ratio for short disease-free period in high-risk EOC groups. Functional studies revealed that ascitic ATX was required for maintaining cancer stem cell-like characteristics and invadopodia formation.ConclusionAscitic ATX levels may serve as a useful prognostic indicator for predicting aggressive behaviour in EOC. ATX-linked invadopodia are a potential target to prevent peritoneal dissemination in ovarian cancer.

VISTA+/CD8+ status correlates with favorable prognosis in Epithelial ovarian cancer.

Immunotherapy by blocking immune checkpoint regulators has emerged as a new targeted therapy for some cancers. Among them V-domain Ig suppressor of Tcell activation (VISTA) which is identified as a novel checkpoint regulator in ovarian cancer. This study aimed to investigate the VISTA role in Epithelial ovarian cancer (EOC), and its relationship with tumor-infiltrating lymphocytes (TILs) markers and its prognostic value. The expression of VISTA, CD3, CD8, CD4, FOXP3, and CD56 was assessed in 168 EOC tissue microarrays (TMA) by immunohistochemistry (IHC). In addition, associations between VISTA, TILs, clinicopathological variables, and overall survival (OS) were analyzed. VISTA expression in IGRov1 cells, as well as in PBMC of EOC patient, was evaluated by western blot. VISTA expression was detected in 64,28% of tissues, among which 42.3% were positive for tumor cells (TCs), and 47,9% were positive for immune cells (ICs). In univariate analysis, VISTA expression was significantly associated with a high density of TILs:CD3+ (p = 0,001), CD4+ (p = 0,002) and CD8+ (p≤0,001), in ICs but not in TCs. In terms of OS, multivariate analysis showed a significant association between the high density of CD8+ TILs and VISTA positive staining in ICs (p = 0,044), but not in TCs (p = 0,108). Kaplan-Meier curves demonstrated no correlation between VISTA expression and prolonged OS in both ICs (p = 0,841) and TCs (p = 0,090). Classification of EOC tumor microenvironment based on VISTA and CD8+TILs expression, demonstrated four immune subtypes: VISTA+/CD8+, VISTA+/CD8-, VISTA-/CD8+ and VISTA-/CD8-. The dual positive VISTA+/CD8+ subtype was significantly associated with prolonged OS in both TCs and ICs (p = 0,012 and p≤0,01, respectively), whereas patients with VISTA+/CD8- had the worst OS. Our results showed that VISTA is highly expressed in the IGRov1 cell line and LT-CD8 from a patient with EOC. Our results highlighted the association of VISTA expression and CD8+ TILs in EOC, with prolonged OS in patients with VISTA+/CD8+ and proposed VISTA as a potential immunotherapeutic target in EOC.

HOXA‑AS3 induces tumor progression through the epithelial‑mesenchymal transition pathway in epithelial ovarian cancer.

HOXA cluster antisense RNA 3 (HOXA‑AS3) is considered to be involved in several malignancies, however, its biological function in the progression of epithelial ovarian cancer (EOC) remains unclear. The present study compared the expression of HOXA‑AS3 in ovarian cancer and normal ovarian tissues and analyzed the association between the expression of HOXA‑AS3 and the survival outcomes of patients with ovarian cancer. RNA interference was used to suppress HOXA‑AS3 expression in ovarian cancer cell lines in order to demonstrate the function of HOXA‑AS3 in ovarian cancer progression. The associations between HOXA‑AS3 and epithelial‑mesenchymal transition (EMT) markers were explored to verify the mechanism of action of HOXA‑AS3 in ovarian cancer. The results of the present study revealed that ovarian cancer tissues exhibited higher HOXA‑AS3 expression than normal ovarian tissues. Clinical data indicated that HOXA‑AS3 was a significant predictor of progression‑free survival and overall survival. Patients with high HOXA‑AS3 expression had a poorer prognosis than patients with low HOXA‑AS3 expression. Invitro experiments using HOXA‑AS3‑knockdown ovarian cancer cell lines demonstrated that HOXA‑AS3 knockdown inhibited cell proliferation and migration. HOXA‑AS3 was a potent inducer and modulator of the expression of EMT pathway‑related markers and interacted with both the mRNA and protein forms of HOXA3. Collectively, the findings of the present study demonstrated that HOXA‑AS3 expression is associated with ovarian cancer progression and thus, may be employed as a prognostic marker and therapeutic target in EOC.

Interleukin-6 and Hypoxia Synergistically Promote EMT-Mediated Invasion in Epithelial Ovarian Cancer via the IL-6/STAT3/HIF-1α Feedback Loop.

Extensive peritoneal spread and capacity for distant metastasis account for the majority of mortality from epithelial ovarian cancer (EOC). Accumulating evidence shows that interleukin-6 (IL-6) promotes tumor invasion and migration in EOC, although the molecular mechanisms remain to be fully elucidated. Meanwhile, the hypoxic microenvironment has been recognized to cause metastasis by triggering epithelial-mesenchymal transition (EMT) in several types of cancers. Here, we studied the synergy between IL-6 and hypoxia in inducing EMT in two EOC cell lines, A2780 cells and SKOV3 cells. Exogenous recombination of IL-6 and autocrine production of IL-6 regulated by plasmids both induced EMT phenotype in EOC cells characterized by downregulated E-cadherin as well as upregulated expression of vimentin and EMT-related transcription factors. The combined effects of IL-6 and hypoxia were more significant than those of either one treatment on EMT. Suppression of hypoxia-inducible factor-1α (HIF-1α) before IL-6 treatment inhibited the EMT phenotype and invasion ability of EOC cells, indicating that HIF-1α occupies a key position in the regulatory pathway of EMT associated with IL-6. EMT score was found positively correlated with mRNA levels of IL-6, signal transducer and activator of transcription 3 (STAT3), and HIF-1α, respectively, in 489 ovarian samples from The Cancer Genome Atlas dataset. Next, blockade of the abovementioned molecules by chemical inhibitors reversed the alteration in the protein levels of EMT markers induced by either exogenous or endogenous IL-6. These findings indicate a positive feedback loop between IL-6 and HIF-1α, and induce and maintain EMT phenotype through STAT3 signaling, which might provide a novel rationale for prognostic prediction and therapeutic targets in EOC.

ODF2L acts as a synthetic lethal partner with WEE1 inhibition in epithelial ovarian cancer models.

WEE1 has emerged as an attractive target in epithelial ovarian cancer (EOC), but how EOC cells may alter their sensitivity to WEE1 inhibition remains unclear. Here, through a cell cycle machinery-related gene RNAi screen, we found that targeting outer dense fiber of sperm tails 2-like (ODF2L) was a synthetic lethal partner with WEE1 kinase inhibition in EOC cells. Knockdown of ODF2L robustly sensitized cells to treatment with the WEE1 inhibitor AZD1775 in EOC cell lines in vitro as well as in xenografts in vivo. Mechanistically, the increased sensitivity to WEE1 inhibition upon ODF2L loss was accompanied by accumulated DNA damage. ODF2L licensed the recruitment of PKMYT1, a functionally redundant kinase of WEE1, to the CDK1-cyclin B complex and thus restricted the activity of CDK1 when WEE1 was inhibited. Clinically, upregulation of ODF2L correlated with CDK1 activity, DNA damage levels, and sensitivity to WEE1 inhibition in patient-derived EOC cells. Moreover, ODF2L levels predicted the response to WEE1 inhibition in an EOC patient-derived xenograft model. Combination treatment with tumor-targeted lipid nanoparticles that packaged ODF2L siRNA and AZD1775 led to the synergistic attenuation of tumor growth in the ID8 ovarian cancer syngeneic mouse model. These data suggest that WEE1 inhibition is a promising precision therapeutic strategy for EOC cells expressing low levels of ODF2L.

Overlapping gene dependencies for PARP inhibitors and carboplatin response identified by functional CRISPR-Cas9 screening in ovarian cancer

PARP inhibitors (PARPi) have revolutionized the therapeutic landscape of epithelial ovarian cancer (EOC) treatment with outstanding benefits in regard to progression-free survival, especially in patients either carrying BRCA1/2 mutations or harboring defects in the homologous recombination repair system. Yet, it remains uncertain which PARPi to apply and how to predict responders when platinum sensitivity is unknown. To shed light on the predictive power of genes previously suggested to be associated with PARPi response, we systematically reviewed the literature and identified 79 publications investigating a total of 93 genes. The top candidate genes were further tested using a comprehensive CRISPR-Cas9 mutagenesis screening in combination with olaparib treatment. Therefore, we generated six constitutive Cas9+ EOC cell lines and profiled 33 genes in a CRISPR-Cas9 cell competition assay using non-essential (AAVS1) and essential (RPA3 and PCNA) genes for cell fitness as negative and positive controls, respectively. We identified only ATM, MUS81, NBN, BRCA2, and RAD51B as predictive markers for olaparib response. As the major survival benefit of PARPi treatment was reported in platinum-sensitive tumors, we next assessed nine top candidate genes in combination with three PARPi and carboplatin. Interestingly, we observed similar dropout rates in a gene and compound independent manner, supporting the strong correlation of cancer cell response to compounds that rely on DNA repair for their effectiveness. In addition, we report on CDK12 as a common vulnerability for EOC cell survival and proliferation without altering the olaparib response, highlighting its potential as a therapeutic target in EOC.

FTO Inhibits Epithelial Ovarian Cancer Progression by Destabilising SNAI1 mRNA through IGF2BP2.

Fat mass and obesity-associated protein (FTO) regulates critical pathways in various diseases, including malignant tumours. However, the functional link between FTO and its target genes in epithelial ovarian cancer (EOC) development remains to be elucidated. In this study, the biological functions of FTO were verified in vitro and in vivo. The m6A modification and the binding sites of SNAI1 mRNA were confirmed by m6A RNA immunoprecipitation (MeRIP) and RIP experiments. The actinomycin D assay was used to test the stability of RNA. We found that FTO was downregulated with increased m6A levels in EOC. Reduced expression of FTO was associated with a higher FIGO stage in patients with EOC. Mechanistically, FTO decreased the m6A level and stability of SNAI1 mRNA, causing downregulation of SNAI1 and inhibiting epithelial-mesenchymal transition (EMT). Furthermore, FTO-mediated downregulation of SNAI1 expression depended on IGF2BP2, which acted as an m6A reader binding to the 3' UTR region of SNAI1 mRNA to promote its stability. In conclusion, FTO inhibits SNAI1 expression to attenuate the growth and metastasis of EOC cells in an m6A-IGF2BP2-dependent manner. Our findings suggest that the FTO-IGF2BP2-SNAI1 axis is a potential therapeutic target in EOC.

Downregulation of LEMD1-AS1 and Its Influences on the Diagnosis, Prognosis, and Immune Infiltrates of Epithelial Ovarian Cancer.

Previous studies have confirmed long noncoding RNA LEMD1-AS1 (LEMD1-AS1) as a functional factor in several tumors. The present work is aimed at exploring the prognostic and diagnostic values of LEMD1-AS1 in patients with epithelial ovarian cancer (EOC). We examined the expressions of LEMD1-AS1 in pan-cancer from TCGA microarray datasets and GTEx Project. The expressions of LEMD1-AS1 were detected by qRT-PCR in EOC specimens and normal ovarian specimens from 30 EOC patients. The χ2 test was applied to compare the clinicopathological characteristics of different groups. ROC curves were established to determine the diagnostic values of LEMD1-AS1 in screening EOC tissues. The association of LEMD1-AS1 expression with clinical outcome was determined by the Kaplan-Meier methods and COX assays. A decreased expression of LEMD1-AS1 was observed in EOC tissues compared to matched normal specimens (p < 0.01). Low LEMD1-AS1 expression could be used to distinguish EOC from adjacent normal specimens. A clinical study revealed that patients with low LEMD1-AS1 expression have a shorter overall survival (p = 0.035) and progress-free interval (p = 0.041) than those with high LEMD1-AS1 expression. The Spearman correlation test revealed that LEMD1-AS1 expressions were negatively associated with the expressions of neutrophil and myeloid dendritic cell. Overall, our finding suggested that LEMD1-AS1 may have potential roles as a potential biomarker and/or a therapeutic target in EOC.

Clinical significance of cadherin-6 expression in primary and recurrent epithelial ovarian cancer and its association with outcomes: A potential therapeutic target for epithelial ovarian cancer (206)

<b>Objectives:</b> Cadherin-6 (CDH6) is a membrane glycoprotein, and aberrant expression of CDH6 has been reported in several human carcinomas, suggesting a possible role in metastasis and invasion. Recently, antibody-drug conjugates (ADCs) targeting CDH6 have drawn attention to new cancer therapies and demonstrated their antitumor activity in preclinical models of epithelial ovarian cancer (EOC). However, limited data are available regarding the frequency of CDH6 expression and its relationship to clinical factors in EOC. Our goal was to understand the clinical significance of CDH6 expression in EOC. <b>Methods:</b> We performed immunohistochemical (IHC) staining on CDH6 expression in a total of 232 EOC surgical samples (including 181 primary tumors and 51 recurrent tumors). CDH6 IHC was performed using the Leica BOND III staining platform with an anti-CDH6 antibody (HPA007456, ATLAS ANTIBODIES). The CDH6 IHC scoring standard refers to the HER2 detection guidelines for gastric cancer (0, 1+, 2+, 3+). We define a score greater than or equal to 1 as positive for the expression of CDH6. <b>Results:</b> We investigated 181 patients with primary EOC for CDH6 expression through IHC. Total 117 (64.6%) patients tested positive. In which, 18 (15.4%), 84 (71.8%) and 15 (12.8%) cases were scored as 1+, 2+ and 3+, respectively. We then investigated the relationship between CDH6 expression and clinical-pathologic features in EOC. CDH6 expression was observed more frequently in high-grade serous carcinomas (89.0%, p < 0.0001), stage III/IV tumors (84.8%, p < 0.0001) and gross residual tumors in primary surgery (84.7%, p < 0.0001). CDH6-positive patients showed shorter progression-free survival (PFS) and overall survival (OS) (p < 0.0001 and p=0.0006) than that of CDH6-negative patients in all EOC patients. In addition, patients with CDH6 3+ had shorter PFS and OS than that of patients who had 0, 1+ and 2+ (p =0.028 and p=0.015) in the high-grade serous subgroup. We also investigated the expression of CDH6 in 51 recurrent EOC; 38/51 (74.5%) recurrent tumors tested positive for CDH6 expression, and nine (23.7%), 17 (44.7%) and 12 (31.6%) received scores of 1+, 2+ and 3+, respectively. CDH6 expression from recurrent tumors was observed in 18/24 (75.0%) high-grade serous, 11/16 (68.8%) clear cell, 4/5 (80.0%) endometrioid and 5/6 (83.3%) other histotypes. <b>Conclusions:</b> CDH6 expression is frequently observed in primary and recurrent EOC of all histotypes, especially in high-grade serous carcinoma. The frequency of CDH6 expression is consistent between primary and recurrent tumors. CDH6 is a promising therapeutic target for the treatment of EOC.

Maelstrom promotes tumor metastasis through regulation of FGFR4 and epithelial-mesenchymal transition in epithelial ovarian cancer

BackgroundIncreasing evidence has indicated that Maelstrom (MAEL) plays an oncogenic role in various human carcinomas. However, the exact function and mechanisms by which MAEL acts in epithelial ovarian cancer (EOC) remain unclear.ResultsThis study demonstrated that MAEL was frequently overexpressed in EOC tissues and cell lines. Overexpression of MAEL was positively correlated with the histological grade of tumors, FIGO stage, and pT/pN/pM status (p < 0.05), and it also acted as an independent predictor of poor patient survival (p < 0.001). Ectopic overexpression of MAEL substantially promoted invasiveness/metastasis and induced epithelial-mesenchymal transition (EMT), whereas silencing MAEL by short hairpin RNA effectively inhibited its oncogenic function and attenuated EMT. Further study demonstrated that fibroblast growth factor receptor 4 (FGFR4) was a critical downstream target of MAEL in EOC, and the expression levels of FGFR4 were significantly associated with MAEL. (P < 0.05).ConclusionOur findings suggest that overexpression of MAEL plays a crucial oncogenic role in the development and progression of EOC through the upregulation of FGFR4 and subsequent induction of EMT, and also provide new insights on its potential as a therapeutic target for EOC.

Abnormal spindle-like microcephaly-associated protein promotes proliferation by regulating cell cycle in epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) ranks first for female gynecological tumor-related deaths. Due to the limited efficacy of traditional chemotherapy strategies, potential therapeutic targets are urgently needed. Previous studies have reported a relationship between abnormal spindle-like microcephaly-associated protein (ASPM) and ovarian cancer based on immunohistochemistry (IHC) and bioinformatics analysis. However, the potential role of ASPM in the proliferation of ovarian cancer cells and its molecular mechanism remain to be elucidated. Therefore, we aimed to further investigate the potential role of ASPM and its underlying mechanism in EOC using integrated online databases, clinical samples, and cell models. We used online databases (Gene Expression Profiling Interactive Analysis, Cbioportal and Kaplan-Meier Plotter) to analyze differential ASPM expression in ovarian carcinoma and explore its prognostic value in ovarian cancer (OvCa) patients. Immunohistochemistry staining based on a clinical tissue microarray (TMA) comprised 75 cases of EOC tissue and 5 cases of adjacent normal ovary tissue was used to detect the ASPM expression and analyze the relationship between ASPM expression and EOC characteristics. Various cell function experiments related to tumorigenesis were performed including the CCK8 assay, 5-ethynyl-2'-deoxyuridine (EdU), colony formation assay and Transwell assay in EOC cell models (A2780 and OVCAR3) with knocked down ASPM by small interfering RNA (siRNA) to observe its role. Finally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment was conducted to determine the signaling pathways in which ASPM was involved in the pathogenesis of ovarian cancer. Analysis of cell cycle distribution using flow cytometry was further performed to verify the pathways. The expression profile based on data from The Cancer Genome Atlas (TCGA) database confirmed ASPM expression in EOC was higher compared with normal tissue, and further analysis suggested that higher expression was correlated with worse patient prognosis. Immunohistochemical analysis further indicated that ASPM was highly expressed in OvCa tissues and associated with a higher pathological stage, grade, and positive lymphatic metastasis. Cell models with knocked down ASPM by small interfering RNA (siRNA) significantly inhibited proliferation and migration. KEGG pathway enrichment and cell cycle analysis showed that ASPM silencing could inhibit ovarian cancer cell proliferation via synthesis (S) phase arrest. Our study confirmed that ASPM promoted proliferation and caused S phase arrest in EOC cells. ASPM may become a potential molecular marker for early screening and a valuable therapeutic target in EOC. Abnormal spindle-like microcephaly-associated protein (ASPM); epithelial ovarian cancer (EOC); prognosis; proliferation.

Exosome Component 4 Promotes Epithelial Ovarian Cancer Cell Proliferation, Migration, and Invasion via the Wnt Pathway.

BackgroundOf gynecologic malignancies, ovarian cancer is the leading cause of death, mainly due to the lack of sensitive tumor markers, which means it almost always presents at an advanced stage. Exosome Component 4 (EXOSC4) is involved in RNA degradation, but its role in epithelial ovarian cancer (EOC) is unclear.MethodsThe expression levels of EXOSC4 in EOC and normal ovarian tissue specimens were determined by immunohistochemical staining. The overall survival (OS) and progression-free survival (PFS) of patients with EOC were evaluated after patients were classified into high and low EXOSC4 expression groups, and the Cox regression model was established to identify independent predictors of patient prognosis. The effects of EXOSC4 on proliferation, colony formation, migration, and invasion were examined in the SKOV-3 and HO8910 cell lines by lentivirus-mediated shRNA knockdown. Flow cytometry was used to detect cell cycle changes. The mRNA levels of cyclin D1, CDK4, and c-myc were detected by RT-PCR. The protein expression levels of β-catenin, cyclin D1, CDK4, c-myc, vimentin, N-cadherin, and E-cadherin were assessed by western blot. Wnt/β-catenin activation was measured by TCF/LEF reporter assay.ResultsEXOSC4 was significantly elevated in EOC tissues and cell lines. High EXOSC4 expression was correlated with the International Federation of Gynecology and Obstetrics (FIGO) stage and pathological grade, and identified as an independent predictor of shorter OS and PFS. EXOSC4 knockdown suppressed proliferation, migration, and invasion in EOC cell lines. Cells were arrested at G0/G1 phase after EXOSC4 knockdown. The mRNA levels of cyclin D1, CDK4, and c-myc were decreased. β-catenin, cyclin D1, CDK4, c-myc, vimentin, and N-cadherin protein expression levels were reduced, while those of E-cadherin was increased. Wnt/β-catenin activity was suppressed after the EXOSC4 knockdown.ConclusionsEXOSC4 is involved in EOC. Knockdown of EXOSC4 can inhibit the proliferation, migration, and invasion ability of EOC by suppressing the Wnt pathway. EXOSC4 is expected to be a novel biomarker and molecular target in EOC.

Voltage-Gated Sodium Channels as Potential Biomarkers and Therapeutic Targets for Epithelial Ovarian Cancer.

Simple SummaryVoltage-gated sodium channels are membrane proteins that change conformation in response to depolarization of the membrane potential, allowing sodium ions to flow into cells. While voltage-gated sodium channels are normally studied in terms of neuron impulses and skeletal or cardiac muscle contraction, abnormal ion channel expression is a feature of many cancer cells. The aim of our study was to assess the expression of voltage-gated sodium channels in ovarian cancer cells. We found that ovarian cancer cells generally express lower levels of voltage-gated sodium channels than normal cells and that two voltage-gated sodium channels, SCN8A and SCN1B, were prognostic biomarkers for ovarian cancer overall survival. In vitro studies suggested that drugs that block voltage-gated sodium channels, such as certain anti-epileptic drugs and local anesthetics, might sensitize ovarian cancer cells to chemotherapy. These findings suggest that voltage-gated sodium channels may be interesting targets for ovarian cancer therapy.Abnormal ion channel expression distinguishes several types of carcinoma. Here, we explore the relationship between voltage-gated sodium channels (VGSC) and epithelial ovarian cancer (EOC). We find that EOC cell lines express most VGSC, but at lower levels than fallopian tube secretory epithelial cells (the cells of origin for most EOC) or control fibroblasts. Among patient tumor samples, lower SCN8A expression was associated with improved overall survival (OS) (median 111 vs. 52 months; HR 2.04 95% CI: 1.21–3.44; p = 0.007), while lower SCN1B expression was associated with poorer OS (median 45 vs. 56 months; HR 0.69 95% CI 0.54–0.87; p = 0.002). VGSC blockade using either anti-epileptic drugs or local anesthetics (LA) decreased the proliferation of cancer cells. LA increased cell line sensitivity to platinum and taxane chemotherapies. While lidocaine had similar additive effects with chemotherapy among EOC cells and fibroblasts, bupivacaine showed a more pronounced impact on EOC than fibroblasts when combined with either carboplatin (ΔAUC −37% vs. −16%, p = 0.003) or paclitaxel (ΔAUC −37% vs. −22%, p = 0.02). Together, these data suggest VGSC are prognostic biomarkers in EOC and may inform new targets for therapy.

Abstract 1459: PTP4A3 phosphatase is a novel drug target for epithelial ovarian cancer

Abstract High grade serous ovarian cancer (HGSOC) is the deadliest epithelial ovarian cancer (EOC) variant, with a bleak outcome that kills &amp;gt;14,000 women annually in the US. In past four decades, first line therapies have changed only modestly. While dramatic advances in targeted- and immune-based therapies have been seen in some solid tumors, they have not been reported in patients with HGSOC. Recurrent and chemoresistant HGSOC is common. Therefore, it is imperative that new HGSOC drug targets be interrogated. The Protein Tyrosine Phosphatases of Regenerating Liver (PRL or PTP4A) family is significantly upregulated in a variety of tumors, including HGSOC. A bioinformatic analysis of the ovarian cancer using the KMplot Survival Database revealed that high PTP4A3 expression was associated with poor survival in EOC (p&amp;lt;0.0001, hazard ratio (HR)=1.35). In HGSOC early stage disease, PTP4A3 expression levels were also correlated with survival (stage I/II- p=0.0013, HR=3.2), with low expressing patients surviving twice as long as high expressing patients (upper quartile survival in low expression cohort = 81.2 months compared to high expression cohort = 44.3 months). This survival difference appeared independent of myc amplification and was more pronounced in advanced disease (stage III/IV). qPCR profiling of established HGSOC cell lines, including Kuramochi, COV362 and OVCAR4, showed 5-20 fold increases in PTP4A3 gene expression versus nonmalignant control cells. A potent, specific, allosteric small molecule inhibitor of PTP4A3, KVX-053, markedly reduced the growth and survival of chemoresistant and chemosensitive EOC cell lines independent of their BRCA or p53 status. Moreover, treatment of the HGSOC OVCAR4 cell line with KVX-053 (1 μM) inhibited the oncogenic Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway through loss of phosphorylation of STAT3. Evaluation of a series of next-generation KVX-053-based analogs including chemodegraders yielded chemotypes with enhanced cytotoxic effects. These results demonstrate a clear path for the development of the PTP4A family of tyrosine phosphatases as a novel therapeutic target in a HGSOC. Citation Format: John Robert Cornelison, Ettore J. Rastelli, Duncan J. Hart, Anna J. Mendelson, Elizabeth R. Sharlow, Peter Wipf, John S. Lazo. PTP4A3 phosphatase is a novel drug target for epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1459.

MRPL15 is a novel prognostic biomarker and therapeutic target for epithelial ovarian cancer.

PurposeTo analyze the role of six human epididymis protein 4 (HE4)‐related mitochondrial ribosomal proteins (MRPs) in ovarian cancer and selected MRPL15, which is most closely related to the tumorigenesis and prognosis of ovarian cancer, for further analyses.MethodsUsing STRING database and MCODE plugin in Cytoscape, six MRPs were identified among genes that are upregulated in response to HE4 overexpression in epithelial ovarian cancer cells. The Cancer Genome Atlas (TCGA) ovarian cancer, GTEX, Oncomine, and TISIDB were used to analyze the expression of the six MRPs. The prognostic impact and genetic variation of these six MRPs in ovarian cancer were evaluated using Kaplan‐Meier Plotter and cBioPortal, respectively. MRPL15 was selected for immunohistochemistry and GEO verification. TCGA ovarian cancer data, gene set enrichment analysis, and Enrichr were used to explore the mechanism of MRPL15 in ovarian cancer. Finally, the relationship between MRPL15 expression and immune subtype, tumor‐infiltrating lymphocytes, and immune regulatory factors was analyzed using TCGA ovarian cancer data and TISIDB.ResultsSix MRPs (MRPL10, MRPL15, MRPL36, MRPL39, MRPS16, and MRPS31) related to HE4 in ovarian cancer were selected. MRPL15 was highly expressed and amplified in ovarian cancer and was related to the poor prognosis of patients. Mechanism analysis indicated that MRPL15 plays a role in ovarian cancer through pathways such as the cell cycle, DNA repair, and mTOR 1 signaling. High expression of MRPL15 in ovarian cancer may be associated with its amplification and hypomethylation. Additionally, MRPL15 showed the lowest expression in C3 ovarian cancer and was correlated with proliferation of CD8+ T cells and dendritic cells as well as TGFβR1 and IDO1 expression.ConclusionMRPL15 may be a prognostic indicator and therapeutic target for ovarian cancer. Because of its close correlation with HE4, this study provides insights into the mechanism of HE4 in ovarian cancer.

Inhibition of sphingosine kinase 2 down-regulates ERK/c-Myc pathway and reduces cell proliferation in human epithelial ovarian cancer.

BackgroundEpithelial ovarian cancer (EOC) is the leading cause of death from female cancers. In our previous study, sphingosine kinase 2 (SphK2) inhibitor was shown to display anti-EOC activities. The purpose of this study was to evaluate further the expression characteristics and clinical significance of SphK2 in EOC and to explore the roles and underlying mechanisms of SphK2 in EOC cell survival.MethodsThe expression of SphK2 was examined by immunohistochemistry (IHC) and Western blot, and its clinical implications and prognostic significance were analyzed. We performed a cellular proliferation assay, and a mouse xenograft model was established to confirm the roles of SphK2 in vitro and in vivo. Cell cycle analysis, apoptosis assay, and Western blot were performed to examine cell cycle progression and apoptosis rate. Gene set enrichment analysis (GSEA), and Western blot were used to investigate the downstream signaling pathways related to SphK2 function.ResultsThe expression level of SphK2 was shown to be associated with stage, histological grade, lymph node metastasis, and ascites status. More importantly, a high SphK2 expression level was a prognostic indicator of overall survival (OS) and relapse-free survival (RFS). Moreover, knockdown of SphK2 arrested cell cycle progression and inhibited EOC cell proliferation both in vitro and in vivo. Furthermore, ERK/c-Myc, the key pathway in EOC progression, was important for SphK2-mediated mitogenic action in EOC cells.ConclusionsOur findings provided the first evidence that SphK2 played a crucial role in EOC proliferation by regulating the ERK/c-Myc pathway. This indicated that SphK2 might serve as a prognostic marker and potential therapeutic target in EOC.

Ct-OATP1B3 Promotes Epithelial Ovarian Cancer Metastasis Via Regulation of Mitochondrial Fatty Acid Oxidation and Oxidative Phosphorylation

Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) is a newly discovered mRNA variant of OATP1B3, which predominantly expresses in various types of cancer specimens. However, very little is known about its biological function in cancer so far. Here, we reveal that Ct-OATP1B3 is overexpressed in epithelial ovarian cancer (EOC) tissues and plays a pivotal role in EOC metastasis. Mechanically, Ct-OATP1B3 directly interacts with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and activates mitochondrial fatty acid oxidation (FAO) and oxidative phosphorylation (OXPHOS) pathways to facilitate adenosine triphosphate (ATP) production and cellular lamellipodia formation in EOC cells. Our study provides an insight into the function and underlying mechanism of Ct-OATP1B3 in EOC metastasis, and highlights Ct-OATP1B3 as a novel prognostic marker as well as therapeutic target in EOC.