Human Ovarian Cancer Tissues Research Articles

Activated PARP1/FAK/COL5A1 signaling facilitates the tumorigenesis of cholesterol-resistant ovarian cancer cells through promoting EMT

Cancer cells require plentiful cholesterol for membrane biogenesis and other functional needs due to fast proliferating, leading to the interaction of cholesterol or its metabolites with cancer-related pathways. However, the impact of long-lasting high cholesterol concentrations on tumorigenesis and its underlying mechanisms remains largely unexplored. To the best of our knowledge, this study is the first to establish a cholesterol-resistant ovarian cancer cells, whose intracellular total cholesterol level up to 6–8 mmol/L. We confirmed that high cholesterol facilitated the progression of ovarian cancer in vitro and in vivo. Notably, our findings revealed significant upregulation of collagen type V alpha 1 chain (COL5A1) expression in cholesterol-resistant ovarian cancer cells and human ovarian cancer tissue, which was depended on FAK/Src activation. Mechanistically, PARP1 directly bound to FAK in response to activate FAK/Src/COL5A1 signaling. Intriguingly, COL5A1 depletion significantly impeded the tumorigenesis of these cells, concomitant with a decrease in epithelial-mesenchymal transition (EMT) progression. In conclusion, PARP1/FAK/COL5A1 signaling activation facilitated progression of cholesterol-resistant ovarian cancer cells by promoting EMT, thereby broadening a new therapeutic opportunity.

MATN2 overexpression suppresses tumor growth in ovarian cancer via PTEN/PI3K/AKT pathway.

The incidence rate of developing ovarian cancer decreases over the years; however, mortality ranks top among malignancies of women, mainly metastasis through local invasion. Matrilin-2 (MATN2) is a member of the matrilin family that plays an important role in many cancers. However, its relationship with ovarian cancer remains unknown. Our study aimed to explore the function and possible mechanism of MATN2 in ovarian cancer. Human ovarian cancer tissue microarrays were used to detect the MATN2 expression in different types of ovarian cancer using immunohistochemistry (IHC). CCK-8, wound scratch healing assay, transwell assay, and flow cytometry were used to detect cell mobility. Gene and protein expression were detected using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. MATN2 interacts with phosphatase, and the tensin homolog (PTEN) deleted on chromosome 10 was analyzed using TCGA database and co-immunoprecipitation (Co-IP). In vivo experiments were conducted using BALB/c nude mice, and tumor volume and weight were recorded. Tumor growth was determined using hematoxylin and eosin (H&E) and IHC staining. MATN2 was significantly downregulated in ovarian cancer cells. The SKOV3 and A2780 cell mobility was significantly inhibited by MATN2 overexpression, while the cell apoptosis rate was significantly increased. MATN2 overexpression decreased transplanted tumor size in vivo. These results were reversed by inhibiting MATN2. Furthermore, we found that PTEN closely interacted with MATN2 using bioinformatics and Co-IP. MATN2 overexpression significantly inhibited the PI3K/AKT pathway, however, PTEN suppression reversed this effect of MATN2 overexpression. These results indicated that MATN2 may play a critical role in ovarian cancer development by inhibiting cells proliferation and migration. The mechanism was related to interacting with PTEN, thus inhibiting downstream effectors in the PI3K/AKT pathway, which may be a novel target for treating ovarian cancer.

LRP8 promotes tumorigenesis in ovarian cancer through inhibiting p53 signaling.

Ovarian cancer (OC) is the most lethal gynecological malignancy with a high mortality rate. Low-density lipoprotein (LDL) receptor-related protein 8 (LRP8) is a cell membrane receptor belonging LDL receptor family and is involved in several tumor progressions. However, there is limited understanding of how LRP8 mediates OC development. LRP8 expression level was identified in human OC tissues and cells using immunohistochemical staining and quantitative polymerase chain reaction assays, respectively. Functions of LRP8 in OC progression were evaluated by Celigo cell counting, wound healing, transwell and flow cytometry assays, and the xenograft models. The human phospho-kinase array analysis was used for screening potential signaling involved in OC development. We observed that LRP8 was overexpressed in OC tissues, and high expression of LRP8 was associated with poor prognosis of OC patients. Functionally, LRP8 knockdown remarkably reduced proliferation and migration of OC cells, and induced apoptosis and S phase cycle arrest. LRP8 deficiency attenuated in vivo tumor growth of OC cells. Moreover, the addition of p53 inhibitor partially reversed the effects of LRP8 knockdown on OC cell proliferation and apoptosis, indicating the involvement of p53 signaling in LRP8-mediated OC progression. This study confirmed that LRP8/p53 axis contributed to OC progression, which might serve as a novel potential therapeutic target for OC patients.

SMAD4 inhibits glycolysis in ovarian cancer through PI3K/AKT/HK2 signaling pathway by activating ARHGAP10.

ARHGAP10 is a tumor-suppressor gene related to ovarian cancer (OC) progression; however, its specific mechanism is unclear. To investigate the effect of ARHGAP10 on OC cell migration, invasion, and glycolysis. Quantitative real-time PCR (qRT-PCR) quantified mRNA and protein expressions of AKT, p-AKT, HK2, and SMAD4 were tested by Western blot. EdU, Wound healing, and Transwell assay were utilized to evaluate OC cell proliferation, migration, and invasion. We used a Seahorse XF24 Extracellular Flux Analyzer to monitor cellular oxygen consumption rates (OCR) and extracellular acidification rates (ECAR). Chromatin immunoprecipitation (ChIP) was used to analyze the transcriptional regulation of ARHGAP10 by SMAD4. ARHGAP10 expression in OC tissues was detected by immunohistochemistry. Our results showed that ARHGAP10 expression was negatively related to lactate levels in human OC tissues. ARHGAP10 overexpression can inhibit the migration, proliferation, and invasion of OC cells, and this function can be blocked by 2-Deoxy-D-glucose. Moreover, we found that ARHGAP10 expression can be rescued with the AKT inhibitor LY294002. This study revealed that the antitumor effects of ARHGAP10 in vivo and in vitro possibly suppress oncogenic glycolysis through the PI3K/AKT/HK2-regulated glycolysis metabolism pathway.

The long non-coding RNA NEAT1 promotes the progression of human ovarian cancer through targeting miR-214-3p and regulating angiogenesis

BackgroundAngiogenesis and metastasis contributes substantially to the poor outcome of patients with ovarian cancer. We aimed to explore the role and mechanisms of the long non-coding RNA NEAT1 (nuclear enriched abundant transcript 1) in regulating angiogenesis and metastasis of human ovarian cancer. NEAT1 expression in human ovarian cancer tissues and cell lines including SKOV-3 and A2780 was investigated through in situ hybridization. Gene knockdown and overexpressing were achieved through lentivirus infection, transfection of plasmids or microRNA mimics. Cell viability was measured with the cell counting kit-8 assay, while apoptosis was determined by flow cytometry. Cell migration and invasion were evaluated by transwell experiments, and protein expression was determined by western blot assays or immunohistochemistry. Duo-luciferase reporter assay was employed to confirm the interaction between NEAT1 and target microRNA. In vivo tumor growth was evaluated in nude mice with xenografted SKOV-3/A2780 cells, and blood vessel formation in tumor was examined by histological staining.ResultsNEAT1 was highly expressed in ovarian cancer tissues of patients and cell lines. MiR-214-3p was identified as a sponging target of NEAT1, and they antagonizedeach other in a reciprocal manner. NEAT1-overexpressing SKOV-3 and A2780 cells had significantly increased proliferation, reduced apoptosis, and augmented abilities of migration and invasion, while cells with NEAT1-knockdown displayed markedly attenuated traits of malignancies. Additionally, the levels of NEAT1 appeared to be positively correlated with the expression levels of angiogenesis-related molecules, including Semaphorin 4D (Sema4D), Sema4D receptor Plexin B1, T-lymphoma invasion and metastasis-inducing protein-1 (Tiam1), and Rho-like GTPases Rac1/2/3. In the xenograft mouse model, more NEAT1 expression resulted in faster in vivo tumor growth, more blood vessel formation in tumor tissues, as well as higher expression levels of angiogenesis-related molecules and CD31.ConclusionsNEAT1 promotes angiogenesis and metastasis in human ovarian cancer. NEAT1 and miR-214-3p are promising targets for developing therapeutics to treat human ovarian cancer.

S1PR1 regulates ovarian cancer cell senescence through the PDK1-LATS1/2-YAP pathway

Cell senescence deters the activation of various oncogenes. Induction of senescence is, therefore, a potentially effective strategy to interfere with vital processes in tumor cells. Sphingosine-1-phosphate receptor 1 (S1PR1) has been implicated in various cancer types, including ovarian cancer. The mechanism by which S1PR1 regulates ovarian cancer cell senescence is currently elusive. In this study, we demonstrate that S1PR1 was highly expressed in human ovarian cancer tissues and cell lines. S1PR1 deletion inhibited the proliferation and migration of ovarian cancer cells. S1PR1 deletion promoted ovarian cancer cell senescence and sensitized ovarian cancer cells to cisplatin chemotherapy. Exposure of ovarian cancer cells to sphingosine-1-phosphate (S1P) increased the expression of 3-phosphatidylinositol-dependent protein kinase 1 (PDK1), decreased the expression of large tumor suppressor 1/2 (LATS1/2), and induced phosphorylation of Yes-associated protein (p-YAP). Opposite results were obtained in S1PR1 knockout cells following pharmacological inhibition. After silencing LATS1/2 in S1PR1-deficient ovarian cancer cells, senescence was suppressed and S1PR1 expression was increased concomitantly with YAP expression. Transcriptional regulation of S1PR1 by YAP was confirmed by chromatin immunoprecipitation. Accordingly, the S1PR1-PDK1-LATS1/2-YAP pathway regulates ovarian cancer cell senescence and does so through a YAP-mediated feedback loop. S1PR1 constitutes a druggable target for the induction of senescence in ovarian cancer cells. Pharmacological intervention in the S1PR1-PDK1-LATS1/2-YAP signaling axis may augment the efficacy of standard chemotherapy.

Anisomycin inhibits the activity of human ovarian cancer stem cells via regulating antisense RNA NCBP2-AS2/MEK/ERK/STAT3 signaling.

Ovarian cancer stem cells (OCSCs) are the main cause of relapse and drug resistance in patients with ovarian cancer. Anisomycin has been shown to be an effective antitumor agent, but its mechanism of action in ovarian cancer remains elusive. CD44+/CD133+ human OCSCs were isolated from human ovarian cancer tissues. OCSCs were interfered with using anisomycin and specific small-interfering RNA (siRNA). Microarray assay, MTT, in vivo tumorigenic experiments, transwell assay, cell cycle assay, colony formation assay, angiogenesis assay, and hematoxylin and eosin staining were used to detect the mechanism of anisomycin with respect to inhibiting the activity of OCSCs. Expression of the NCBP2-AS2/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK)/signal transducer and activator of transcription 3 (STAT3) pathway was examined using western blotting, a quantitative real-time PCR (RT-qPCR) and immunofluorescence staining. Bioinformatics analysis was used for predictive analysis of NCBP2-AS2 expression in urogenital tumors. Microarray analysis showed that treatment with anisomycin significantly decreased the expression of antisense RNA NCBP2-AS2 in OCSCs. In vitro cellular experiments showed that interfering with endogenous antisense RNA NCBP2-AS2 using siRNA distinctly inhibited the proliferation, migration and angiogenesis of OCSCs, whereas in vivo animal experiments revealed decreased tumorigenesis in nude mice. Moreover, the results of RT-qPCR and western blotting demonstrated that both anisomycin treatment and NCBP2-AS2 silencing led to significant reductions in the mRNA and protein expression levels of NCBP2-AS2, MEK, ERK and STAT3. From a bioinformatic point of view, antisense RNA NCBP2-AS2 exhibited significantly differential expression between urogenital tumors and normal controls, and a similar expression pattern was found in the genes NCBP2, RPL35A, DNAJC19 and ECE2, which have similarity to NCBP2-AS2. Anisomycin suppresses the in vivo and in vitro activity of human OCSCs by downregulating the antisense RNA NCBP2-AS2/MEK/ERK/STAT3 signaling pathway, whereas the antisense RNA NCBP2-AS2 and genes with similarity have the potential to serve as markers for clinical diagnosis and prognosis of urogenital tumors.

Ginsenoside 20(S)-Rg3 reduces KIF20A expression and promotes CDC25A proteasomal degradation in epithelial ovarian cancer

BackgroundGinsenoside 20(S)-Rg3 shows promising tumor-suppressive effects in ovarian cancer via inhibiting NF-κB signaling. This study aimed to explore the downstream tumor suppressive mechanisms of ginsenoside Rg3 via this signaling pathway. Materials and methodsA systematical screening was applied to examine the expression profile of 41 kinesin family member genes in ovarian cancer. The regulatory effect of ginsenoside Rg3 on KIF20A expression was studied. In addition, we explored interacting proteins of KIF20A and their molecular regulations in ovarian cancer. RNA-seq data from The Cancer Genome Atlas (TCGA) was used for bioinformatic analysis. Epithelial ovarian cancer cell lines SKOV3 and A2780 were used as in vitro and in vivo cell models. Commercial human ovarian cancer tissue arrays were used for immunohistochemistry staining. ResultsKIF20A is a biomarker of poor prognosis among the kinesin genes. It promotes ovarian cancer cell growth in vitro and in vivo. Ginsenoside Rg3 can suppress the transcription of KIF20A. GST pull-down and co-immunoprecipitation (IP) assays confirmed that KIF20A physically interacts with BTRC (β-TrCP1), a substrate recognition subunit for SCFβ−TrCP E3 ubiquitin ligase. In vitro ubiquitination and cycloheximide (CHX) chase assays showed that via interacting with BTRC, KIF20A reduces BTRC-mediated CDC25A poly-ubiquitination and enhances its stability. Ginsenoside Rg3 treatment partly abrogates KIF20A overexpression-induced CDC25A upregulation. ConclusionThis study revealed a novel anti-tumor mechanism of ginsenoside Rg3. It can inhibit KIF20A transcription and promote CDC25A proteasomal degradation in epithelial ovarian cancer.

ELK3 Targeting AEG1 Promotes Migration and Invasion of Ovarian Cancer Cells under Hypoxia.

Ovarian cancer (OC) is one of the most common tumors in female reproductive organs with a five-year survival rate of less than 45%. Metastasis is a crucial contributor to OC development. ETS transcription factor (ELK3), as a transcriptional factor, have been involved in multiple tumor development. However, its role in OC remains elusive. In this study, we observed high expression of ELK3 and AEG1 in human OC tissues. OVCAR-3 and SKOV3 cells were treated with hypoxia to mimic tumor microenvironment in vivo. We found that the expression of ELK3 was significantly increased in cells under hypoxia compared with normoxia. ELK3 knockdown inhibited cell migration and invasion abilities under hypoxia. Moreover, ELK3 knockdown decreased β-catenin expression and inhibited the activation of Wnt/β-catenin pathway in SKOV3 cells under hypoxia. Astrocyte-elevated gene-1 (AEG1) has been reported to promote OC progression. Our results showed that the mRNA level of AEG1 was decreased when ELK3 knockdown under hypoxia. Dural luciferase assay confirmed that ELK3 bound to gene AEG1 promoter (-2005-+15) and enhanced its transcriptional activity under hypoxia. Overexpression of AEG1 increased the migration and invasion abilities of SKOV3 cell with ELK3 knockdown. In the absence of ELK3, the activation of β-catenin was recovered by AEG1 overexpression. To sum up, we conclude that ELK3 promotes AEG1 expression by binding to its promoter. ELK3 could promote migration and invasion of OC cells by targeting AEG1, which provides a potential basis for therapeutic approaches to OC.

Signal transducer and activator of transcription 3 and cancer associated fibroblasts jointly generate chemo-resistance and affect prognosis in epithelial ovarian cancer

Objective: To investigate the mechanism of signal transducer and activator of transcription 3 (STAT3) and cancer associated fibroblasts (CAF) jointly generate chemo-resistance in epithelial-ovarian cancer and their effect on prognosis. Methods: A total of 119 patients with high-grade ovarian serous cancer who received surgery in Cancer Hospital of Chinese Academy of Medical Sciences from September 2009 to October 2017 were collected. The clinico-pathological data and follow-up data were complete. Multivariate Cox regression model was used to analyze the prognostic factors. Ovarian cancer tissue chips of patients in our hospital were prepared. EnVision two-step method immunohistochemistry was used to detect the protein expression levels of STAT3, the specific markers of CAF activation, fibroblast activating protein (FAP), and type Ⅰ collagen (COL1A1) secreted by CAF. The relationship between the expression of STAT3, FAP, COL1A1 protein and drug resistance and prognosis of ovarian cancer patients was analyzed, and the correlation between the expression of three proteins was analyzed. These results were verified through the gene expression and prognostic information of human ovarian cancer tissues collected in the GSE26712 dataset of gene expression omnibus (GEO) database. Results: (1) Multivariate Cox regression model analysis showed that chemotherapy resistance was an independent risk factor for overall survival (OS) of ovarian cancer (P<0.001). (2) The expression levels of STAT3, FAP, and COL1A1 proteins in chemotherapy resistant patients were significantly higher than those in chemotherapy sensitive patients (all P<0.05). Patients with high expression of STAT3, FAP, and COL1A1 had significantly shorter OS than those with low expression (all P<0.05). According to the human ovarian cancer GSE26712 dataset of GEO database, patients with high expression of STAT3, FAP, and COL1A1 also showed shorter OS than patients with low expression (all P<0.05), the verification results were consistent with the detection results of ovarian cancer patients in our hospital. (3) Correlation analysis showed that the protein level of STAT3 was positively correlated with FAP and COL1A1 in our hospital's ovarian cancer tissue chips (r=0.47, P<0.001; r=0.30, P=0.006), the analysis of GEO database GSE26712 dataset showed that the expression of STAT3 gene and FAP, COL1A1 gene were also significantly positively correlated (r=0.31, P<0.001; r=0.52, P<0.001). Conclusion: STAT3 and CAF could promote chemotherapy resistance of ovarian cancer and lead to poor prognosis.

Abstract 416: Phosphorylation of CDK9 transduces ALK signaling to promote resistance to PARP inhibitors via RNA Pol II activated homologous recombination repair

Abstract Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) are currently the most promising drugs to induce synthetic lethality in tumor with homologous recombination (HR) deficiency. However, development of resistance to PARPi is an almost universal occurrence in tumor despite initial sensitivity. Additionally, how to identify the right patients for PARPi monotherapy or in combination with other agents remains a substantial clinical challenge. Therefore, understanding the molecular underpinnings of PARPi resistance is critical to the development of rational combinatorial treatment strategies and identification of novel biomarkers which will in turn facilitate optimization of outcomes for patients receiving PARPi. By employing a screening procedure using phospho-RTK antibody array, our study identifies phosphorylated ALK (p-ALK) expression is higher in PARPi/platinum resistant cells relative to sensitive cells. We further demonstrate that p-ALK expression in human ovarian cancer tissue is associated with resistance to PARPi and platinum-based chemotherapy. Notably, FDA approved ALK inhibitors induce an HR-deficient phenotype and sensitize PARPi/platinum-resistant tumors to PARPi in vitro and in vivo. Mechanistically, ALK contributes to PARPi resistance by tyrosine phosphorylating CDK9 at Y19, thereby increasing the protein stability and kinase activity of CDK9 which in turn stabilizes positive transcriptional elongation factor b (P-TEFb) to activate RNA pol II and turn on HR repair genes transcription. Importantly, the phosphorylated counterparts of ALK/CDK9 complex (p-ALK/p-Y19 CDK9) can serve as a biomarker to identify patients with PARPi/platinum-resistant tumors which most likely to respond to dual PARP and ALK inhibition. Together, our findings identify p-ALK/p-Y19-CDK9 mediated stabilization of P-TEFb as a critical mechanism of PARPi resistance and supports a biomarker-guided therapeutic strategy combining ALKi and PARPi to induce synthetic lethality. Citation Format: Yu-Yi Chu, Jianjun Gao, Dihua Yu, Mien-Chie Hung. Phosphorylation of CDK9 transduces ALK signaling to promote resistance to PARP inhibitors via RNA Pol II activated homologous recombination repair [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 416.

Abstract 2266: Tumor associated neutrophils (TAN) may produce neutrophil extracellular traps (NETs) which can suppress the infiltration of activated T cells in tumor tissue

Abstract Objective: High density of tumor-infiltrating lymphocytes (TIL) in the tumor is associated with favorable prognosis of cancer patients. It has been reported that many neutrophils also infiltrate in various tumor tissues as tumor-associated neutrophils (TAN) which produce considerable amounts of neutrophil extracellular traps (NETs). However, the crosstalk between TAN and TIL and its impact on tumor behavior have not been fully examined. Methods: Neutrophils and mononuclear cells (PBMC) were collected from the blood of healthy donor. Neutrophils were stimulated with PMA or LPS for 15 min, washed extensively, and incubated for another 4 hours to produce NETs. PBMC were cultured on anti-CD3 mAb-coated plate with recombinant-IL-2 for 7-14days. The migration of activated T cells through 3μm pore to CXCL-11 was examined in vitro. The localization and densities of TAN and TIL were immunohistochemically evaluated in 38 human serous ovarian cancer tissue. NETs were quantified with the density of CD66b(+) and Citrullinated Histon H3(+) cells. Results: Chemotactic migration of T cells to CXCL-11 was inhibited by 99%±1.6% (p&amp;lt;0.001) in the presence of PMA-activated neutrophils in lower chamber. The inhibition was similarly detected when NET components were removed by ultracentrifugation. Timelapse analysis also showed the NETs-depleted supernatant inhibited random migration, which was totally canceled by the pretreatment with catalase. When neutrophils were activated by LPS, T cell migration was also inhibited by 49%±19.9% (p&amp;lt;0.01), but not by NETs-depleted supernatant. In western blotting, CXCL11 was totally degraded by LPS-stimulated neutrophils, which was greatly reduced by the depletion of NET component and restored by DNase I as well as phenylmethylsulfonyl fluoride (PMSF) or Neutrophil elastase inhibitor (NEI). The reduced migration induced by LPS-stimulated neutrophils was also restored with these reagents. In ovarian cancer tissues, density of TIL was greater in tumors with diameter ≥10cm than that of tumors &amp;lt;10cm (p=0.04). However, the densities of TIL and NETs were irrelevant with age, tumor stage and neutrophil-to-lymphocyte ratio (NLR) in peripheral blood. Multicolor immunohistochemistry showed that TAN and TIL tended to be reciprocally distributed in tumor stroma in most of the ovarian cancer tissues. Cit-H3 was positively detected in 2.1%~75% of CD66b(+) TANs, and the proportion of NET in TAN greatly varied among tumors. In all cases, the densities of CD4(+) and CD8(+) T cells inversely correlated with that of NETs (r = -0.5182, p = 0.0012; r = -0.5684, p = 0.0003, respectively). Conclusion: Activated neutrophils negatively regulate T cell migration partially through NET formation. TAN may suppress T cell traffic into tumor tissue, which may attenuate cell-mediated immunity in tumor microenvironment and promote tumor progression. Citation Format: Kohei Tamura, Hideyo Miyato, Misaki Matsumiya, Rei Takahashi, Yuki Kaneko, Yurie Futoh, Kazuya Takahashi, Yuki Kimura, Akira Saito, Hideyuki Ohzawa, Yasushi Saga, Yuji Takei, Hiroyuki Fujiwara, Joji Kitayama. Tumor associated neutrophils (TAN) may produce neutrophil extracellular traps (NETs) which can suppress the infiltration of activated T cells in tumor tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2266.

SPOCK1 Overexpression Suggests Poor Prognosis of Ovarian Cancer

Sparc/osteonectin, cwcv, and kazal-like domains proteoglycan 1 (SPOCK1) has been found in a variety of malignant tumors and is associated with a poor prognosis. We aimed to explore the role of SPOCK1 in ovarian cancer. Ovarian cancer cell lines SKOV3 and SW626 were transfected with SPOCK1 overexpressing or empty vector using electroporation. Cells were studied by immunostaining and an automated Western blotting system. BrdU uptake and wound healing assays assessed cell proliferation and migration. SPOCK1 expression in human ovarian cancer tissues and in blood samples were studied by immunostaining and ELISA. Survival of patients with tumors exhibiting low and high SPOCK1 expression was analyzed using online tools. Both transfected cell lines synthesized different SPOCK1 variants; SKOV3 cells also secreted the proteoglycan. SPOCK1 overexpression stimulated DNA synthesis and cell migration involving p21CIP1. Ovarian cancer patients had increased SPOCK1 serum levels compared to healthy controls. Tumor cells of tissues also displayed abundant SPOCK1. Moreover, SPOCK1 levels were higher in untreated ovarian cancer serum and tissue samples and lower in recipients of chemotherapy. According to in silico analyses, high SPOCK1 expression was correlated with shorter survival. Our findings suggest SPOCK1 may be a viable anti-tumor therapeutic target and could be used for monitoring ovarian cancer.

MiR-5195-3p functions as a tumor suppressor by targeting RHBDD1 in ovarian cancer.

Recent studies have reported the tumor suppressive role of miR-5195-3p in the progression of several cancers, but the potential roles of miR-5195-3p in ovarian cancer (OC) remain largely unknown. We first analyzed the expression levels of miR-5195-3p in 83 pairs of human OC tissues and adjacent specimens by reverse transcription-quantitative PCR. The correlation of miR-5195-3p/rhomboid domain containing 1 (RHBDD1) and clinicopathological parameters was analyzed by chi-square test. The prognostic value of miR-5195-3p was evaluated by Kaplan-Meier method Cox proportional hazards models. The effects of miR-5195-3p on cell proliferation, cell cycle distribution, migration and invasion were examined by CCK-8 assay, colony formation assay, flow cytometry and transwell assay. Tumor forming was evaluated by nude mice model in vivo. The association between miR-5195-3p and RHBDD1 was verified by luciferase reporter assay. We observed that miR-5195-3p level was remarkably reduced in OC tissues as compared to adjacent tissues. The expression of miR-5195-3p was associated with FIGO stage, depth of invasion and poor survival prognosis in OC patients. Overexpression of miR-5195-3p significantly suppressed cell proliferation, cell cycle G1/S transition, migration and invasion in OC cell lines (SKOV-3 and OVCAR3), while knockdown of miR-5195-3p obtained the opposite results. We further confirmed miR-5195-3p as a negative post-transcriptional modulator of RHBDD1. RHBDD1 expression was upregulated in OC tissues compared with adjacent tissues, which was inversely correlated with miR-5195-3p expression. The expression of RHBDD1 was associated with FIGO stage and distant metastasis. RHBDD1 overexpression reversed the suppressive role of miR-5195-3p on OC cell proliferation, migration and invasion. Consistent with the in vitro results, miR-5195-3p overexpression decreased the growth of subcutaneously inoculated tumors in nude mice. Taken together, the present results indicated that miR-5195-3p acts a tumor suppressor by targeting RHBDD1 in OC.

NRF2 controls iron homeostasis and ferroptosis through HERC2 and VAMP8.

Enhancing the intracellular labile iron pool (LIP) represents a powerful, yet untapped strategy for driving ferroptotic death of cancer cells. Here, we show that NRF2 maintains iron homeostasis by controlling HERC2 (E3 ubiquitin ligase for NCOA4 and FBXL5) and VAMP8 (mediates autophagosome-lysosome fusion). NFE2L2/NRF2 knockout cells have low HERC2 expression, leading to a simultaneous increase in ferritin and NCOA4 and recruitment of apoferritin into the autophagosome. NFE2L2/NRF2 knockout cells also have low VAMP8 expression, which leads to ferritinophagy blockage. Therefore, deletion of NFE2L2/NRF2 results in apoferritin accumulation in the autophagosome, an elevated LIP, and enhanced sensitivity to ferroptosis. Concordantly, NRF2 levels correlate with HERC2 and VAMP8 in human ovarian cancer tissues, as well as ferroptosis resistance in a panel of ovarian cancer cell lines. Last, the feasibility of inhibiting NRF2 to increase the LIP and kill cancer cells via ferroptosis was demonstrated in preclinical models, signifying the impact of NRF2 inhibition in cancer treatment.

ANKRD22 is a potential novel target for reversing the immunosuppressive effects of PMN-MDSCs in ovarian cancer

BackgroundOvarian cancer is the deadliest type of malignant gynecological tumor. Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) are involved ovarian cancer and are closely related to adverse outcomes. However, the immunosuppressive mechanism...

Cancer-associated fibroblasts contribute to cancer metastasis and apoptosis resistance in human ovarian cancer via paracrine SDF-1α.

Cancer-associated fibroblasts (CAFs), one of the main members of stromal cells in tumor microenvironment are proposed to play a central role in promoting tumor metastasis. It is unclear whether and how CAFs mediates tumor metastasis or chemoresistance in human ovarian cancer. CAFs were extracted from human ovarian cancer tissues (OCs) of patients with different kinds of histological types. We found that CAFs showed more aggressive potency than those tumor cells, both of which were isolated from the same ovarian cancer specimen. Moreover, when co-cultured with CAFs, cell migration abilities of ovarian cancer cells (SKOV3, OVCAR3 and HEY) were significantly increased. Next, we preliminarily detected a higher CAFs density in sections of metastatic lesions than those in primary tumor site of primary OCs clinically. However, no significant difference of stromal derived factors-1α (SDF-1α) production from CAFs was found between primary and metastatic lesions. Additionally, in contrast with tumor cells, CAFs exhibited obvious apoptosis resistance when treated with cisplatin. Furthermore, we found that cisplatin-induced cytotoxicity and apoptosis were significantly inhibited by co-cultured with recombinant human SDF-1α in SKOV3 in a time and dose-dependent manner, and this effect was suppressed by the CXCR4 antagonist AMD3100. CAFs might be involved in the malignant metastasis in human ovarian cancer through promoting cell migration in tumor cells. And their resistance to cytotoxic agents might be mediated by paracrine SDF-1α/CXCR4 signaling in ovarian cancer.

Hsa_circ_0001445 works as a cancer suppressor via miR-576-5p/SFRP1 axis regulation in ovarian cancer.

Ovarian cancer (OC) has high mortality and morbidity. Circular RNA (circRNA) can deeply impact the tumor occurrence and growth. The pathogenic activity of one particular circRNA, hsa_circ_0001445 (hcR1445), in OC remains unclear and was therefore analyzed in this study. Human OC tissue specimens and cell lines (SKOV3, HO8910, and OVCAR8) were used to examine the levels of hcR1445 and the microRNA miR-576-5p using polymerase chain reaction. The 5-ethynyl-2'-deoxyuridine, flow cytometry, cellular scratch test, CCK-8, and Transwell migration assays were used to examine the biological activities of hcR1445 and miR-576-5p on cell apoptosis, invasion, migration, and proliferation in OC cells. Protein expression of WNT/β-catenin and secreted frizzled-related protein 1 (SFRP1) were tested using Western blot analysis. The potential interactions of miR-576-5p/SFRP1 and hcR1445/miR-576-5p were evaluated using a dual-luciferase report assay. The effect of hcR1445 on OC growth and metastasis was further determined using an OC tumor xenograft model in vivo. hcR1445 level was declined in OC cells and tissues. hcR1445 reduced cellular invasion, proliferation, and migration by blocking the ability of miR-576-5p to upregulate SFRP1 expression and consequently prohibit WNT/β-catenin signal transduction. hcR1445 upregulation suppressed OC growth, development, and intraperitoneal metastasis in vivo. hcR1445 acts an antioncogene by targeting the miR-576-5p/SFRP1 axis and blocking OC progression and development. Thus, hcR1445 may be employed as an indicator or a possible therapeutic target in OC patients.

ALG3 Promotes Peritoneal Metastasis of Ovarian Cancer through Increasing Interaction of α1,3-mannosylated uPAR and ADAM8.

Peritoneal metastasis is the main cause of poor prognoses and high mortality in ovarian cancer patients. Abnormal protein glycosylation modification is associated with cancer malignancy. Elevated α1,3-mannosyltransferase 3 (ALG3), which catalyzes the α1,3-mannosylation of glycoproteins, has been found in some malignant tumors. However, the pathological significance of ALG3 and its regulatory mechanism in ovarian cancer metastasis is unclear. The results showed that the level of ALG3/α1,3-mannosylation was higher in human ovarian cancer tissues compared with normal ovarian tissues, as measured by Lectin chip, Western blot and Lectin blot analyses, as well as ovarian tissue microarray analysis. ALG3 was also correlated with the poor prognosis of ovarian cancer patients, according to survival analysis. The downregulation of ALG3 decreased the proliferation, stemness and peritoneal metastasis of ovarian cancer cells. The increase in urokinase plasminogen activator receptor (uPAR) α1,3-mannosylation catalyzed by ALG3 enhanced urokinase plasminogen activator (uPA)/uPAR activation and the interaction of uPAR with a disintegrin and metalloproteinase 8 (ADAM8), which promoted ovarian cancer peritoneal metastasis via the ADAM8/Ras/ERK pathway. Furthermore, decreased ALG3 suppressed ascites formation and the peritoneal metastasis of ovarian cancer cells in mice. This study highlights ALG3 as a potential diagnostic biomarker and prospective therapeutic target for ovarian cancer.

SLC7A1 Overexpression Is Involved in Energy Metabolism Reprogramming to Induce Tumor Progression in Epithelial Ovarian Cancer and Is Associated with Immune-Infiltrating Cells.

Cationic amino acid transporters (SLC7A1/CAT1) are highly expressed in human ovarian cancer (OC) tissues. However, the specific biological functions and mechanisms involved remain unclear. We used bioinformatics analysis to explore SLC7A1 expression level, prognostic value, and tumor mutation burden (TMB) in ovarian cancer (OC) tissues. We performed in vitro experiments to identify the expression and biological function of SLC7A1 in epithelial ovarian cancer (EOC) tissues and cells. An amino acid autoanalyzer was used to detect the effect of SLC7A1 on amino acid metabolism in EOC cells. Finally, SLC7A1 in OC was evaluated for cell-to-cell signalling and immune infiltration using online databases. We found that increased SLC7A1 expression in EOC cells and tissues was associated with poorer survival outcomes (P < 0.05) but not with tumor stage or grade of OC (P > 0.05). SLC7A1 is involved in the transport of phenylalanine and arginine in EOC cells, and its knockdown reduced the proliferation and migration of EOC cells and the resistance of cells to cisplatin. Furthermore, the TIMER database indicated that SLC7A1 overexpression was significantly positively correlated with levels of CD4+ memory resting cells, CD8+ effector memory cells, M0 macrophages, and cancer-associated fibroblasts (CAFs) in OC (P < 0.05) and significantly negatively correlated with CD4+ memory-activated cells (P < 0.05). Cell immunofluorescence indicated that SLC7A1 overexpression may affect the distribution of immune-infiltrating lymphocytes in tumors by inhibiting the expression of CCL4. Therefore, we concluded that SLC7A1 is involved in the metabolic remodelling of amino acids in EOC to promote tumor development and cisplatin resistance and is related to the tumor-infiltrating immune microenvironment of OC. SLC7A1 is a biomarker for predicting EOC progression and cisplatin resistance and represents a promising target for EOC treatment.