Epithelial-mesenchymal Transition In Ovarian Cancer Research Articles

Unraveling the molecular mechanisms of lymph node metastasis in ovarian cancer: focus on MEOX1

BackgroundLymph node metastasis (LNM) is a major factor contributing to the high mortality rate of ovarian cancer, making the treatment of this disease challenging. However, the molecular mechanism underlying LNM in ovarian cancer is still not well understood, posing a significant obstacle to overcome.ResultsThrough data mining from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, we have identified MEOX1 as a specific gene associated with LNM in ovarian cancer. The expression of MEOX1 was found to be relatively high in serous ovarian adenocarcinoma, and its higher expression were associated with increased tumor grade and poorer clinical prognosis for ovarian cancer patients. Bioinformatics analysis revealed that MEOX1 exhibited the highest mRNA levels among all cancer types in ovarian cancer tissues and cell lines. Furthermore, gene set enrichment analysis (GSEA) and pathway analysis demonstrated that MEOX1 was involved in various LNM-related biological activities, such as lymphangiogenesis, lymphatic vessel formation during metastasis, epithelial-mesenchymal transition (EMT), G2/M checkpoint, degradation of extracellular matrix, and collagen formation. Additionally, the expression of MEOX1 was positively correlated with the expression of numerous prolymphangiogenic factors in ovarian cancer. To validate our findings, we conducted experiments using clinical tissue specimens and cell lines, which confirmed that MEOX1 was highly expressed in high-grade serous ovarian cancer (HGSOC) tissues and various ovarian cancer cell lines (A2780, SKOV3, HO8910, and OVCAR5) compared to normal ovarian tissues and normal ovarian epithelial cell line IOSE-80, respectively. Notably, we observed a higher protein level of MEOX1 in tumor tissues of LNM-positive HGSOC compared to LNM-negative HGSOC. Moreover, our fundamental experiments demonstrated that suppression of MEOX1 led to inhibitory effects on ovarian cancer cell proliferation and EMT, while overexpression of MEOX1 enhanced the proliferation and EMT capacities of ovarian cancer cells.ConclusionsThe results of our study indicate that MEOX1 plays a role in the lymph node metastasis of ovarian cancer by regulating multiple biological activities, including the proliferation and EMT of ovarian cancer, lymphangiogenesis, and ECM remodeling. Our findings suggest that MEOX1 could serve as a potential biomarker for the diagnosis and treatment of ovarian cancer with LNM.

FSH induces EMT in ovarian cancer via ALKBH5-regulated Snail m6A demethylation.

Background: The therapeutic benefits of targeting follicle-stimulating hormone (FSH) receptor in treatment of ovarian cancer are significant, whereas the role of FSH in ovarian cancer progresses and the underlying mechanism remains to be developed. Methods: Tissue microarray of human ovarian cancer, tumor xenograft mouse model, and in vitro cell culture were used to investigate the role of FSH in ovarian carcinogenesis. siRNA, lentivirus and inhibitors were used to trigger the inactivation of genes, and plasmids were used to increase transcription of genes. Specifically, pathological characteristic was assessed by histology and immunohistochemistry (IHC), while signaling pathway was studied using western blot, quantitative RT-PCR, and immunofluorescence. Results: Histology and IHC of human normal ovarian and tumor tissue confirmed the association between FSH and Snail in ovarian cancer metastasis. Moreover, in epithelial ovarian cancer cells and xenograft mice, FSH was showed to promote epithelial mesenchymal transition (EMT) progress and metastasis of ovarian cancer via prolonging the half-life of Snail mRNA in a N6-methyladenine methylation (m6A) dependent manner, which was mechanistically through the CREB/ALKBH5 signaling pathway. Conclusions: These findings indicated that FSH induces EMT progression and ovarian cancer metastasis via CREB/ALKBH5/Snail pathway. Thus, this study provided new insight into the therapeutic strategy of ovarian cancer patients with high level of FSH.

RIPK4 Promotes Cell Invasion and the Epithelial-Mesenchymal Transition in Ovarian Cancer.

To investigate the clinical role and biological function of receptor-interacting protein kinase 4 (RIPK4) in ovarian cancer (OC). We conducted a comprehensive analysis of the expression and prognostic role of RIPK4 in OC using various public databases including The Cancer Genome Atlas, Oncomine, and Kaplan-Meier plotter. In vitro studies included wound healing, cell migration and invasion, cell proliferation, and cell apoptosis assays as well as vascular mimicry experiments. In vivo studies were conducted using subcutaneous and intraperitoneal xenografts. Our findings revealed that RIPK4 was significantly overexpressed in OC tissue compared to normal ovarian tissue. Moreover, the overexpression of RIPK4 was associated with advanced-stage disease and a poor prognosis in OC patients. RIPK4 silencing resulted in significant inhibition of intraperitoneal tumor growth, invasion, and vascular mimicry in OC cells. Furthermore, downregulation of RIPK4 inhibited the epithelial-mesenchymal transition of OC cells both in vitro and in vivo by promoting the expression of E-cadherin and inhibiting the expression of N-cadherin. The results of this study suggest that RIPK4 may function as an oncogene in the development and prognosis of OC.

Exosome Secretion and Epithelial-Mesenchymal Transition in Ovarian Cancer Are Regulated by Phospholipase D.

Phospholipase D (PLD) isoenzymes participate in a variety of cellular functions that are mostly attributed to phosphatidic acid (PA) synthesis. Dysregulation of PLD regulates tumor progression and metastasis, yet little is known about the underlying mechanism. We previously reported on the expression and clinical role of the PLD isoenzymes PLD1 and PLD2 in tubo-ovarian high-grade serous carcinoma (HGSC). In the present study, we investigated the biological function of PLD1 and PLD2 using the OVCAR-3 and OVCAR-8 HGSC cell lines. KO cell lines for both PLDs were generated using CRISPR/CAS9 technology and assayed for exosome secretion, spheroid formation, migration, invasion and expression of molecules involved in epithelial-mesenchymal transition (EMT) and intracellular signaling. Significant differences between PLD1 and PLD2 KO cells and controls were observed for all the above parameters, supporting an important role for PLD in regulating migration, invasion, metastasis and EMT.

Multiomics characterization implicates PTK7 in ovarian cancer EMT and cell plasticity and offers strategies for therapeutic intervention

Most patients with ovarian cancer (OC) are diagnosed at a late stage when there are very few therapeutic options and a poor prognosis. This is due to the lack of clearly defined underlying mechanisms or an oncogenic addiction that can be targeted pharmacologically, unlike other types of cancer. Here, we identified protein tyrosine kinase 7 (PTK7) as a potential new therapeutic target in OC following a multiomics approach using genetic and pharmacological interventions. We performed proteomics analyses upon PTK7 knockdown in OC cells and identified novel downstream effectors such as synuclein-γ (SNCG), SALL2, and PP1γ, and these findings were corroborated in ex vivo primary samples using PTK7 monoclonal antibody cofetuzumab. Our phosphoproteomics analyses demonstrated that PTK7 modulates cell adhesion and Rho-GTPase signaling to sustain epithelial-mesenchymal transition (EMT) and cell plasticity, which was confirmed by high-content image analysis of 3D models. Furthermore, using high-throughput drug sensitivity testing (525 drugs) we show that targeting PTK7 exhibited synergistic activity with chemotherapeutic agent paclitaxel, CHK1/2 inhibitor prexasertib, and PLK1 inhibitor GSK461364, among others, in OC cells and ex vivo primary samples. Taken together, our study provides unique insight into the function of PTK7, which helps to define its role in mediating aberrant Wnt signaling in ovarian cancer.

Detection of circulating tumor cells and evaluation of epithelial-mesenchymal transition patterns of circulating tumor cells in ovarian cancer.

BackgroundCirculating tumor cells (CTCs) have considered to be promising liquid biopsy in cancer due to the intact information of whole cells and the potential to reflect micrometastasis. However, CTCs research are extremely limited in ovarian cancer, probably due to their rarity. The predictive value of CTCs and circulating tumor microemboli (CTM) in metastasis remains to be elucidated in ovarian cancer. This study tried to identify CTCs/CTM in ovarian cancer with considerably positive rate. To preliminarily identify the invasive capacity of CTCs/CTM, the epithelial-mesenchymal transition (EMT) patterns of CTCs/CTM was evaluated. Moreover, for comprehensive understanding of invasiveness of disseminated cells in ovarian cancer, EMT pattern of exfoliated tumor cells in ascites were also confirmed in this study.MethodsPeripheral blood samples and ascites samples were collected from 22 ovarian cancer patients. The Microfiltration combined with morphological analysis was used to detect CTC single cells or cell clusters. Microfiltration combined with morphological analysis was applied in the CTC isolation and identification. EMT was evaluated by immunofluorescence via markers including vimentin and cytokeratin.ResultsMicrofiltration combined with morphological analysis was introduced to detect CTCs/CTM with a positivity rate of 40.9% in ovarian cancer patients. The number of CTC varied from 1 to 8, with CTM number from 4 to 30. CTCs/CTM of all samples have experienced EMT process. Vimentin was expressed in all CTC samples and all tumor cells in ascites, while cytokeratin was expressed in 44.4% (4/9) of CTC samples. There were no significant differences of the clinical parameters between the CTC-positive and CTC-negative patients.ConclusionsThis study showed that both CTCs/CTM and detached tumor cells in ascites might have undergone complete or partial EMT in ovarian cancer. Moreover, microfiltration combined with cytomorphological analysis showed a considerable CTC detection rate.

MiRNA-651-3p regulates EMT in ovarian cancer cells by targeting ZNF703 and via the MEK/ERK pathway

miRNAs are non-coding single-stranded RNA molecules with many functions. Several miRNAs have been found to be dysregulated in ovarian cancer; however, the role of miR-651-3p in ovarian cancer remains unknown. Here, the expression level of miR-651-3p in ovarian tissue samples was determined via qRT-PCR, and then miR-651-3p was overexpressed and downregulated to study the functional changes in ovarian cancer cells. Based on previous research and database predictions, we analyzed the binding and regulatory effects of miR-651-3p on zinc finger protein 703 (ZNF703). We additionally evaluated the effect of miR-651-3p on epithelial–mesenchymal transition (EMT) and mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathways in ovarian cancer cells. We found that miR-651-3p was downregulated in ovarian cancer tissues. miR-651-3p expression was associated with inhibited proliferation, invasion, and migration of ovarian cancer cells and promoted cell cycle arrest. Additionally, miR-651-3p was found to target ZNF703 and affect EMT in ovarian cancer by activating the MEK/ERK signaling pathway. MiR-651-3p was downregulated in ovarian cancer, and suppressed the malignant biological behavior of ovarian cancer by inhibiting ZNF703 and the MEK/ERK pathway. Our findings on miR-651-3p provided new insights for the diagnosis and treatment of ovarian cancer.

Effect of WWOX on epithelial-mesenchymal transition in ovarian cancer cells in vivo, and its association with Elf5/Snail-1 signal pathway

Purpose: To investigate how WW domain-containing oxidoreductase (WWOX) gene affects epithelial-mesenchymal transition (EMT) of ovarian cancer (OC) cells, and the implication of Elf5/Snail-1 pathway in the process.
 Methods: This study employed female BALB/c nude mice aged 6 weeks. The expression levels of E-cadherin, β-Catenin, N-cadherin, Vimentin, Snail1 and Elf5 were assayed using qRT-PCR. The protein levels of WW1, WW2, E-cad, β-Cat, N-cad, vimentin, Snail-1 and Elf5 were determined using western blotting (WB). Invasion changes in cells in each group were analyzed by Transwell invasion test while WWOX and Elf5 were evaluated by GST pull-down test; furthermore, WWOX and ELF5 were evaluated by co-immunoprecipitation (COIP).
 Results: Relative to control group, tumor volume and weight of WWOX high-expression mice were significantly decreased, while those of WWOX low-expression group were increased (p < 0.05). The levels of E-cad, Elf5 and β-catenin increased, but those of N-cad, Snail-1 and vimentin decreased in WWOX high expression group. In the WWOX low-expression group, the levels of E-cad, Elf5 and β-cat were down-regulated, while those of N-cad, Snail-1 and vimentin were up-regulated (p < 0.05). The expression of E-cad, Elf5 and β-cat declined; on the other hand, those of N-Cad, Snail-1 and vimentin were elevated after mutation of WW1 domain in WWOX gene (p < 0.05).
 Conclusion: Based on the in vivo results, the role of WWOX/Elf5/Snail1 signal route in the epithelial-mesenchymal transition of ovarian cancer, and its related mechanisms have been clarified. This provides a new target for gene therapy of ovarian cancer.

Multi-Omics Analysis of the Therapeutic Value of MAL2 Based on Data Mining in Human Cancers

Recent studies have reported that T-cell differentiation protein 2 (MAL2) is an important regulator in cancers. Here, we downloaded data from multiple databases to analyze MAL2 expression and function in pan-cancers, especially in ovarian cancer (OC). Gene Expression Profiling Interactive Analysis (GEPIA) databases was used to examine MAL2 expression in 13 types of cancer. Kaplan–Meier plotter database was used to analyze the overall survival rate of MAL2 in pan-cancers. The Catalog of Somatic Mutations in Cancer (COSMIC), cBioPortal, and UCSC databases were used to examine MAL2 mutation in human cancers. Metascape, STRING, and GeneMANIA websites were used to explore MAL2 function in OC. Furthermore, ggplot2 package and ROC package were performed to analyze hub gene expression and undertake receiver operating characteristic (ROC) analysis. Drug sensitivity of MAL2 in OC was examined by the GSCALite database. In order to verify the results from databases above, real-time quantitative polymerase chain reaction (qRT-PCR) and western blotting were conducted to detect the expression of MAL2 in OC cells. CRISPR/Cas9 system was used to knockout the MAL2 gene in the OC cell lines HO8910 and OVCAR3, using specific guide RNA targeting the exons of MAL2. Then, we performed proliferation, colony formation, migration, and invasion assays to investigate the impact of MAL2 in OC cell lines in vivo and in vitro. Epithelial-mesenchymal transition (EMT)-associated biomarkers were significantly altered in vitro via western blotting and qRT-PCR. Taken together, we observed that MAL2 was remarkably dysregulated in multiple cancers and was related to patient overall survival (OS), mutation, and drug sensitivity. Furthermore, experimental results showed that MAL2 deletion negatively regulated the proliferation, migration, invasion, and EMT of OC, indicating that MAL2 is a novel oncogene that can activate EMT, significantly promote both the proliferation and migration of OC in vitro and in vivo, and provide new clues for treatment strategies.

LINC00974 sponges miR-33a to facilitate cell proliferation, invasion, and EMT of ovarian cancer through HMGB2 upregulation.

The function and mechanism of long intergenic non-protein coding RNA 974 (LINC00974) are rarely reported in ovarian cancer (OC). The study aimed to investigate how LINC00974 affects the progression of OC. The expression levels of LINC00974, microRNA-33a (miR-33a), and high mobility group box 2 (HMGB2) mRNA were detected by qRT-PCR. The LINC00974/miR-33a/HMGB2 axis was confirmed by dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP), and biotinylated RNA pull-down assays. A series of in vitro experiments were employed to assess the effects of LINC00974/miR-33a/HMGB2 axis on the proliferation, invasion and epithelial mesenchymal transition (EMT) of OC cells. Results showed that LINC00974 and HMGB2 mRNA expression were upregulated in OC cells, while miR-33a expression was downregulated. HMGB2 was a direct target gene of miR-33a. LINC00974 act as a competing endogenous RNA (ceRNA) to directly bind with miR-33a, thereby upregulated HMGB2 expression. Notably, silencing of LINC00974 suppressed cell proliferation, invasion and EMT of OC cells, whereas miR-33a knockdown partially reversed the phenotypes of LINC00974 on OC cells. Overall, our study demonstrated that LINC00974 sponges miR-33a to promote cell proliferation, invasion, and EMT of OC through HMGB2 upregulation. LINC00974/miR-33a/HMGB2 axis may be an important signaling pathway in the progression of OC.

Overexpression of Long Noncoding RNA H19 Downregulates miR-140-5p and Activates PI3K/AKT Signaling Pathway to Promote Invasion, Migration and Epithelial-Mesenchymal Transition of Ovarian Cancer Cells.

Objective The abnormal expression of LncRNA H19 and miR-140-5p has been linked to ovarian cancer (OC). Whether H19 directly regulates miR-140-5p in ovarian cancer cells has been unclear. In this study, we deeply explored the relationship between H19 and miR-140-5p in ovarian cancer and the mechanism of action in regulating OC progression. Methods A total of 66 patients with OC admitted to the hospital from June 2017 to June 2019 were selected as the research group (RG), and meanwhile, 60 cases of healthy subjects were selected as the control group (CG). In addition, OC cells and normal ovarian epithelial cells were used to detect H19 and miR-140-5p expression levels and to analyze the effect of H19 on OC cells. The activation of the PI3K/AKT pathway and downstream proteins were analyzed by western blot. Results H19 was highly expressed while miR-140-5p was lowly expressed in OC patients and cell lines (P < 0.050). The proliferation, invasion, migration ability, and epithelial-mesenchymal transition (EMT) of OC cells were reduced after inhibiting H19 expression, and the apoptosis rate was increased. Transfection of cells with miR-140-5p mimics brought opposite effects. Online prediction and dual-luciferase reporter (DLR) confirmed that H19 directly binds miR-140-5p. Western blot assay indicated overexpression activated the PI3K/AKT signaling pathway in OC cells. Moreover, overexpression promoted tumor growth in nude mice and was suppressed by PI3K inhibitor. Conclusion LncRNA H19 downregulation of miR-140-5p to activate the PI3K/AKT signaling pathway and promote the proliferation, invasion, migration and EMT of OC.

Downregulation of RIPK4 Expression Inhibits Epithelial-Mesenchymal Transition in Ovarian Cancer through IL-6.

RIPK4 has been implicated in multiple cancer types, but its role in ovarian cancer (OC) has not been clearly elucidated. Our data from Gene Expression Profiling Interactive Analysis, RT-PCR, and immunohistochemical analysis showed that RIPK4 was expressed at higher levels in OC tissues and cells than in normal ovarian tissues and cells. Increased RIPK4 expression in OC markedly correlated with a worse overall survival than lower RIPK4 expression levels (hazard rate (HR) 1.5 (1.45–1.87); P = 0.001). In functional experiments, RIPK4 downregulation significantly inhibited metastatic behaviours in OC cells. Subsequently, based on data from 593 OC patients in the TCGA database, gene set enrichment analysis revealed that RIPK4 was involved in epithelial-mesenchymal transition (EMT) in OC. At the molecular level, silencing RIPK4 significantly downregulated vimentin, N-cadherin, and Twist expression but induced an increase in the protein level of E-cadherin and inhibited the IL-6 and STAT3 levels. Moreover, IL-6 levels were significantly decreased in RIPK4-silenced OC cells (P < 0.05). The addition of IL-6 to OC cells rescued the suppressive effect of RIPK4 knockdown on EMT. Thus, our data illustrate that downregulation of RIPK4 expression can restrain EMT in OC by inhibiting IL-6. This finding may provide a novel diagnostic and therapeutic target for improving the poor prognoses of OC patients.

Kinesin Family Member C1 (KIFC1) Regulated by Centrosome Protein E (CENPE) Promotes Proliferation, Migration, and Epithelial-Mesenchymal Transition of Ovarian Cancer.

BackgroundCentrosome amplification is recognized as a hallmark of cancer. Kinesin family member C1 (KIFC1), a centrosome-clustering molecule, is essential for the viability of extra centrosome-bearing cancer cells and may be the basis for the progression of ovarian cancer. However, its biological function and mechanism in ovarian cancer have not yet been studied.Material/MethodsQuantitative reverse-transcription polymerase chain reaction was performed to detect the levels of KIFC1 and centrosome protein E (CENPE). Further, cell viability was analyzed with CCK-8 assay, and immunofluorescence was used to measure the expression of Ki67 and PCNA. Cell migration was analyzed with wound healing and transwell assays. Western blot analysis was performed to measure the expression of proteins in ovarian cancer cells. The relationship between KIFC1 and CENPE was investigated by performing co-immunoprecipitation.ResultsKIFC1 was upregulated in ovarian cancer cells, especially in SKOV3 cells. Additionally, we found that KIFC1 silencing in SKOV3 cells inhibited cell proliferation and downregulated the expression of Ki67 and PCNA. Further, the knockdown of KIFC1 suppressed cell migration and epithelial-mesenchymal transition (EMT) and regulated the expression of matrix metalloproteinase (MMP)2, MMP9, E-cadherin, N-cadherin, Snail, and ZEB1. Next, we found that KIFC1 bound to and positively regulated CENPE, a tumor promoter in certain human cancers. All the suppressive effects triggered by KIFC1 inhibition were reversed by CENPE overexpression.ConclusionsKIFC1 contributed to cell proliferation, migration, and EMT via interacting with CENPE in ovarian cancer. KIFC1 might be a potential biomarker and therapeutic target in ovarian cancer patients.

KRT7 promotes epithelial‑mesenchymal transition in ovarian cancer via the TGF‑β/Smad2/3 signaling pathway.

Keratin 7 (KRT7) is a member of the keratin gene family. KRT7 is abnormally expressed in various types of cancer and promotes the malignant progression of tumors. However, the role of KRT7 in ovarian cancer remains unclear. The present study aimed to validate the role of KRT7 in ovarian cancer progression. KRT7 expression levels in patients with ovarian cancer were analyzed using data obtained from the Human Protein Atlas and The Cancer Genome Atlas databases. KRT7 mRNA and protein expression levels were upregulated in ovarian cancer tissue compared with normal tissue. KRT7 expression was associated with the grading, staging and poor prognosis of ovarian cancer. The differentially expressed genes affected by KRT7 were primarily enriched in the functions of cell migration, cell adhesion and cell growth. In vitro studies, including a CCK8 assay, were used to detect cell proliferation. In addition, wound healing and transwell assays were performed to analyze cell migration. The results demonstrated that KRT7 overexpression was associated with increased proliferation, migration and epithelial-mesenchymal transition (EMT) of ovarian cancer cells, and the migration and EMT of ovarian cancers cells were decreased following knockdown with KRT7 small interfering RNA. In vivo, knockdown of KRT7 inhibited tumor growth of ovarian cancer. Furthermore, KRT7 regulated EMT in ovarian cancer via the TGF-β/Smad2/3 pathway, and regulated cell-matrix adhesion through integrin-β1-focal adhesion kinase signaling. These results suggest that KRT7 may be a potential molecular marker for prognosis prediction in patients with ovarian cancer.

Effects of activating GABAB1 receptor on proliferation, migration, invasion and epithelial-mesenchymal transition of ovarian cancer cells

ObjectiveThis study aimed to explore the effects of activating GABAB1 receptor by baclofen on proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of ovarian cancer cells.ResultsOne hundred μmol/L, 200 μmol/L and 300 μmol/L were selected as low, medium and high baclofen concentrations respectively. Cells were divided into four groups: Control, 100 μmol/L, 200 μmol/L and 300 μmol/L. Compared with the control group, the viability, colony formation, migration and invasion of SKOV3 cells were inhibited, and the apoptosis of SKOV3 cells were enhanced significantly at 200 μmol/L and 300 μmol/L baclofen. Moreover, they changed significantly with the increase of baclofen concentration. Compared with the control group, the expression of E-cadherin and GABAB1 increased and the N-cadherin expression decreased significantly in 200 μmol/L and 300 μmol/L groups. Higher concentration of baclofen induced higher expression of E-cadherin and lower expression of N-cadherin.ConclusionBaclofen inhibited the proliferation, cloning, migration, invasion and EMT of ovarian cancer cells by activating GABAB1 receptor. These results might contribute a lot to clarify the role and possible mechanism of GABAB1 receptor in ovarian cancer.

Down-regulation of PADI2 prevents proliferation and epithelial-mesenchymal transition in ovarian cancer through inhibiting JAK2/STAT3 pathway in vitro and in vivo, alone or in combination with Olaparib

BackgroundEpithelial ovarian cancer (EOC) is the most lethal disease among female genital malignant tumors. Peptidylarginine deiminase type II(PADI II) has been shown to enhance a variety of cancers carcinogenesis, including ovarian cancer. The purpose of this study was to investigate the biological role of PADI2 in ovarian cancer (OC) and the relative mechanism.MethodsGene Expression Profiling Interactive Analysis (GEPIA) (https://gepia.pku.cn/) and ONCOMINE (https://www.oncomine.org/) were used to analyze PADI2 Gene Expression data. The survival curve for the PADI2 gene was generated by using the online Kaplan–Meier mapping site (https://www.kmplot.com/). We conducted MTT assay, cloning formation assay and EdU cell proliferation assay to detect the cell activity of PADI2 knockdown A2780 and SKOV3 ovarian cancer cells treated with Olaparib. Cell migration and invasion were observed by would healing and transwell assay. The pathway changes after the treatment of PADI2 were detected by transcriptome sequencing and western blot. The role of PADI2 combined with Olaparib treatment in vivo was studied in nude mouse model bearing ovarian cancer tumor.ResultsWe investigated the role of PADI2 on EOC in vitro and in vivo. PADI2 was upregulated in ovarian cancer samples and high PADI2 expression was correlated with poor outcome. Downregulating PADI2 suppressed colony formation, proliferation, migration and invasion of A2780 and SKOV3 cells. Furthermore, downregulating PADI2 and Olaparib combination treatment attenuated the viability, migration and invasion of A2780 and SKOV3 cells. We identified differentially expressed genes in A2780-shPADI2 and SKOV3-shPADI2 cell by transcriptome sequencing analysis and verified that downregulating PADI2 and Olaparib combination treatment suppresses EMT and JAK2/STAT3 signaling pathway in A2780 and SKOV3 cells in vitro and in vivo.ConclusionsDownregulation of PADI2 and Olaparib combination treatment attenuated the proliferation, migration and invasion of A2780 and SKOV3 cells by inhibiting the EMT through JAK2/STAT3 signaling pathway.

CircRNA FGFR3 induces epithelial-mesenchymal transition of ovarian cancer by regulating miR-29a-3p/E2F1 axis.

Circular RNAs (circRNAs) are a class of non-coding RNAs that regulate gene expression after transcription. However, the specific function of circRNAs in ovarian cancer remains undetermined. Previous studies have demonstrated abnormal expression of circFGFR3 in several cancers. The present study was designed to reveal the roles of circFGFR3 in ovarian cancer (OC). CircFGFR3 expression in OC tissues and cells was detected by RT-qPCR. The effects of CircFGFR3 on OC cells were evaluated by transwell assay and CCK-8 assay. Finally, the underlying mechanism was further revealed by luciferase reporter assay and western blotting. Our results showed that circFGFR3 expression was higher in OC cells and tissues than in normal ovarian cells and adjacent normal tissues; in addition, in OC patients, a high level of CircFGFR3 was related to lower survival rates and higher recurrence rates than a low level of circFGFR3. CircFGFR3 overexpression promotes OC progression by inducing epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, circFGFR3 upregulates E2F1 expression by sponging miR-29a-3p, and the overexpression of E2F1 or the suppression of miR-29a-3p induces OC cell EMT. Therefore, circFGFR3 serves as a promoter of OC by inducing OC cell EMT via the miR-29a-3p/E2F1 axis and circFGFR3 may be a prognostic biomarker for OC patients.

Gα13-mediated LATS1 down-regulation contributes to epithelial-mesenchymal transition in ovarian cancer.

Gα13, a heterotrimeric G-protein of the Gα12/13 subfamily, is associated with aggressive phenotypes in various human cancers. However, the mechanisms by which Gα13 promotes cancer progression have not been fully elucidated. Here, we demonstrate that the activation of Gα13 induces epithelial-mesenchymal transition in ovarian cancer (OvCa) cells through down-regulation of large tumor suppressor kinase (LATS) 1, a critical component of the Hippo signaling pathway. A synthetic biology approach using a mutant GPCR and chimeric G-protein revealed that Gα13-regulated phosphorylation of LATS1 at serine 909 within its activation loop induced recruitment of the itchy E3 ubiquitin protein ligase to trigger LATS1 degradation. Our findings uncover novel mechanisms through which Gα13 activation induces dysregulation of the Hippo signaling pathway, which leads to aggressive cancer phenotypes, and thereby identify a potential target for preventing the metastatic spread of OvCa.-Yagi, H., Onoyama, I., Asanoma, K., Hori, E., Yasunaga, M., Kodama, K., Kijima, M., Ohgami, T., Kaneki, E., Okugawa, K., Yahata, H., Kato, K. Gα13-mediated LATS1 down-regulation contributes to epithelial-mesenchymal transition in ovarian cancer.

P38 Stabilizes Snail by Suppressing DYRK2-Mediated Phosphorylation That Is Required for GSK3β-βTrCP-Induced Snail Degradation.

Snail is a key regulator of epithelial-mesenchymal transition (EMT), which is a major step in tumor metastasis. Although the induction of Snail transcription precedes EMT, posttranslational regulation, especially phosphorylation of Snail, is critical for determining Snail protein levels or stability, subcellular localization, and the ability to induce EMT. To date, several kinases are known that enhance the stability of Snail by preventing its ubiquitination; however, the molecular mechanism(s) underlying this are still unclear. Here, we identified p38 MAPK as a crucial posttranslational regulator that enhances the stability of Snail. p38 directly phosphorylated Snail at Ser107, and this effectively suppressed DYRK2-mediated Ser104 phosphorylation, which is critical for GSK3β-dependent Snail phosphorylation and βTrCP-mediated Snail ubiquitination and degradation. Importantly, functional studies and analysis of clinical samples established a crucial role for the p38-Snail axis in regulating ovarian cancer EMT and metastasis. These results indicate the potential therapeutic value of targeting the p38-Snail axis in ovarian cancer. SIGNIFICANCE: These findings identify p38 MAPK as a novel regulator of Snail protein stability and potential therapeutic target in ovarian cancer.

MiR-99a suppressed cell proliferation and invasion by directly targeting HOXA1 through regulation of the AKT/mTOR signaling pathway and EMT in ovarian cancer.

Ovarian cancer (OC) is the third frequently tumor worldwide. MicroRNA-99a (miR-99a), acting as a tumor suppressor, has been reported to be downregulated in multiple tumors. We aimed at exploring the significant roles of miR-99a in ovarian cancer. Quantitative Real-time polymerase chain reaction (qRT-PCR) and Western blotting were applied to calculate the mRNA and protein levels of miR-99a and its target genes. Kaplan-Meier method was conducted to evaluate the overall survival of ovarian cancer patients. CCK8 and transwell assays were performed to measure the proliferative and invasive abilities. miR-99a, acting as a prognosis predictor, was downregulated in ovarian cancer tissues and cell lines. miR-99a mediated the expression of homeobox A1 (HOXA1) through directly targeting to the 3'-untranslated region (3'-UTR) of its mRNA in ovarian cancer cell lines. miR-99a inhibited the proliferation of ovarian cancer by AKT/mTOR pathway in vitro and in vivo, and it suppressed the invasion-mediated epithelial-mesenchymal transition (EMT) through direct targeting to the 3'-UTR of HOXA1 mRNA. miR-99a suppressed the proliferation through AKT/mTOR signaling pathway and the invasion-mediated EMT in ovarian cancer. The newly identified miR-99a/HOXA1/AKT/mTOR axis provides novel insight into the pathogenesis of ovarian cancer.