Human Epithelial Ovarian Cell Lines Research Articles

Targeting Mitochondrial Cholesterol Efflux via TCF21/ABCA10 Pathway to Enhance Cisplatin Efficacy in Ovarian Cancer.

Cisplatin (DDP) resistance is one of the causes of treatment failure for ovarian cancer (OV). Mitochondrial cholesterol level was reported to be associated with OV chemoresistance. We found that ABCA10, a potential cholesterol transport protein, was highly expressed in ovarian tissues and downregulated in OV tissues. Our study aimed to explore TCF21/ABCA10 axis resistance to DDP therapy in ovarian cancer based on regulating mitochondrial cholesterol efflux. Thirty epithelial ovarian cancer tumors and thirty ovarian tissues from non-cancer patients were collected. Western blot and RT-qPCR were used to measure ABCA10 and TCF21 expression levels in these tissues, as well as in a human ovarian epithelial cell line (IOSE-80), OV cells (A2780 and SKOV3), and DDP-resistant OV cell lines (A2780/DDP and SKOV3/DDP). IOSE-80 cells were also infected with ABCA10 knockdown lentivirus to identify the most effective ABCA10 knockdown plasmid. Lentiviral infection was used to create ABCA10 knockdown, ABCA10 overexpression, and TCF21 overexpression anti-DDP OV cell lines. Cell proliferation was detected by CCK-8 and EDU staining, flow cytometry for apoptosis, MTT for metabolic activity, calcium-induced Cytochrome C release, and mitochondrial matrix swelling for mitochondrial function and Oil Red O staining for lipid accumulation. Cholesterol metabolism was evaluated by measuring mitochondrial cholesterol and cholesterol efflux. Protein concentration was determined using the BCA method. A dual-luciferase reporter assay confirmed TCF21's interaction with ABCA10. ChIP also verified this interaction. The mRNA level (P < 0.01) and protein level (P < 0.001) of ABCA10 were downregulated in cancer tissues of OV patients relative to normal ovarian tissues. Relative to human ovarian epithelial cells, ABCA10 expression was significantly downregulated in OV cells (P < 0.01) and even more significantly downregulated in DDP-resistant OV cells (P < 0.001). Compared to the group treated solely with DDP, the overexpression of ABCA10 significantly inhibited the proliferation of DDP-resistant OV cells (P < 0.01), markedly reduced the staining intensity of EDU in these cells (P < 0.05), and substantially accelerated apoptosis in DDP-resistant OV cells (P < 0.01).Overexpression of ABCA10 further accelerated Cytochrome C expression and mitochondrial matrix swelling in DDP-resistant OV cells compared to the DDP-alone group (P < 0.01). The addition of cholesterol reversed the decrease in lipid accumulation, the decrease in mitochondrial cholesterol levels (P < 0.05), and the increase in cholesterol efflux (P < 0.01) in DDP-resistant OV cells caused by overexpression of ABCA10. The transcription factor TCF21 was bound to the promoter of ABCA10. Overexpression of TCF21 significantly increased ABCA10 expression in DDP-resistant OV cells (P < 0.01) and increased cytochrome C expression in A2780/DDP (P < 0.05) and SKOV3/DDP (P < 0.01) cells, with accelerated mitochondrial matrix swelling in A2780/DDP (P < 0.01) and SKOV3/DDP (P < 0.001) cells, while knockdown of ABCA10 reversed these effects. Our study found that TCF21 boosts ABCA10 expression, which in turn reduces DDP resistance in OV cells by enhancing mitochondrial cholesterol efflux. This mechanism increases the sensitivity of DDP-resistant OV cells to DDP. Our findings will provide new therapeutic targets for the treatment of ovarian cancer.

Evaluation of effects of bisphenol analogs AF, S, and F on viability, proliferation, production of selected cancer-related factors, and expression of selected transcripts in Caov-3 human ovarian epithelial cell line

Bisphenol A (BPA) has been a substantial additive in plastics until the reports on its adverse effects have led to its restrictions and replacement. Monitoring studies document the increasing occurrence of bisphenol analogs, however, data on their effects and risks is still insufficient. Based on the indications that BPA might contribute to ovarian cancer pathogenesis, we examined effects of the analogs AF (BPAF), S (BPS) and F (BPF) (10−9–10−4 M) on the Caov-3 epithelial cancer cells, including the impact on cell viability, proliferation, oxidative stress, and production and expression of several factors and genes related to ovarian cancer. At environmentally relevant doses, bisphenols did not exert significant effects. At the highest concentration, BPAF caused varied alterations, including decreased cell viability and proliferation, caspase activation, down-regulation of PCNA and BIRC5, elevation of IL8, VEGFA, MYC, PTGS2 and ABCB1 expressions. Only BPA (10−4 M) increased IL-6, IL-8 and VEGFA output by the Caov-3 cells. Each bisphenol induced generation of reactive oxygen species and decreased superoxide dismutase activity at the highest concentration. Although the effects were observed only in the supraphysiological doses, the results indicate that certain bisphenol analogs might affect several ovarian cancer cell characteristics and merit further investigation.

Knockdown of heat shock protein family D member 1 (HSPD1) promotes proliferation and migration of ovarian cancer cells via disrupting the stability of mitochondrial 3-oxoacyl-ACP synthase (OXSM)

BackgroundHeat shock protein 60 (HSP60) is essential for the folding and assembly of newly imported proteins to the mitochondria. HSP60 is overexpressed in most types of cancer, but its association with ovarian cancer is still in dispute. SKOV3 and OVCAR3 were used as experimental models after comparing the expression level of mitochondrial HSP60 in a normal human ovarian epithelial cell line and four ovarian cancer cell lines.ResultsLow HSPD1 (Heat Shock Protein Family D (HSP60) Member 1) expression was associated with unfavorable prognosis in ovarian cancer patients. Knockdown of HSPD1 significantly promoted the proliferation and migration of ovarian cancer cells. The differentially expressed proteins after HSPD1 knockdown were enriched in the lipoic acid (LA) biosynthesis and metabolism pathway, in which mitochondrial 3-oxoacyl-ACP synthase (OXSM) was the most downregulated protein and responsible for lipoic acid synthesis. HSP60 interacted with OXSM and overexpression of OXSM or LA treatment could reverse proliferation promotion mediated by HSPD1 knockdown.ConclusionsHSP60 interacted with OXSM and maintained its stability. Knockdown of HSPD1 could promote the proliferation and migration of SKOV3 and OVCAR3 via lowering the protein level of OXSM and LA synthesis.

Promoting action of long non-coding RNA small nucleolar RNA host gene 4 in ovarian cancer.

Long non-coding RNA (LncRNA) small nucleolar RNA host gene 4 (SNHG4) has been shown to be aberrantly expressed in a variety of cancers and involved in cancer development, but its role in ovarian cancer (OC) is unclear. The purpose of this study was to explore the biological function of SNHG4 in OC and reveal its potential downstream molecular targets. OC tumor tissue and normal tissue were collected; normal human ovarian epithelial cell line (IOSE80) and human ovarian cancer cell line (A2780, SKOV-3, OV-90 and CAOV3) were selected. RT-qPCR was used to detect SNHG4, miR-98-5p, and TMED5, while western blot was used to detect the protein expression levels of TMED5, Ki67, MMP-9, Bcl-2, Bax, Gsk3β, Wnt3a, and β-catenin. The subcellular localization of SNHG4 was assessed by nucleocytoplasmic separation assay. CCK-8, colony formation assay, flow cytometry, and Transwell were used to assess the biological behavior of OC cells. The targeting relationship between SNHG4, miR-98-5p and TMED5 was verified by dual luciferase reporter assay and RIP assay. In OC, SNHG4 and TMED5 were highly expressed, and miR-98-5p was underexpressed. Knockdown of SNHG4 inhibited OC cell proliferation, migration and invasion, promoted apoptosis, and prevented Wnt/β-catenin pathway activation. The effect of knockdown of SNHG4 was reversed by knockdown of miR-98-5p or overexpression of TMED5. Mechanistically, SNHG4 competitively adsorbed miR-98-5p to mediate TMED5 expression, thereby activating the Wnt/β-catenin pathway. SNHG4 accelerates OC development via mediating the miR-98-5p/TMED5 axis and activating the Wnt/β-Catenin pathway. SNHG4 gene silencing might be a novel option for OC treatment.

Expression of selected nuclear receptors in human epithelial ovarian cell line Caov3 exposed to bisphenol derivatives.

Objectives. Bisphenol A (BPA) is an indispensable industrial chemical. However, as a proven endocrine disruptor, it may be associated with several health disturbances, including the reproductive functions impairment and cancer. Due to the restriction of BPA usage, many bisphenol derivatives gradually substitute BPA. However, studies have reported adverse biological effects of BPA analogs, but the specific sites of their action remain largely unknown. Nuclear receptors (NRs) appear to play significant roles in various types of cancer. In addition, they are considered relevant targets of bisphenols. In the present study, we investigated the effects of BPA and its analogs bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) on mRNA expression of selected NRs in the human ovarian epithelial cell line Caov3. The NRs examined included retinoic acid receptor α (RARA), retinoid X receptor α (RXRA), peroxisome proliferator activating receptor β/δ (PPARD), chicken ovalbumin upstream promoter-transcription factor 2 (COUPTFII), and nuclear receptor-related protein 1 (NURR1). Methods. Caov3 cells were treated with the bisphenols at the concentrations of 1 nM, 100 nM, 10 µM and 100 µM. After 24 h and 72 h of incubation, cell viability was determined by the MTS assay, and the selected genes expression was analyzed using RT-qPCR. Results. Bisphenol treatment did not affect Caov3 cell viability, except the significant impairment after exposure to the highest BPAF dose (100 µM). At lower doses, neither bisphenol analog altered the expression of the NRs. However, at the highest concentration (100 µM), BPAF and BPA altered the mRNA levels of PPARD, COUPTFII, and NURR1 in a time- and receptor-specific manner. Conclusions. The effects of bisphenols on the specific NRs in the epithelial ovarian cancer cells were addressed for the first time by the present study. Although generally we did not find that bisphenols may provoke significant alterations in the expression of the selected NRs in Caov3 cells, they may alter mRNA expression of certain NRs at high concentrations.

The traditional Chinese medicine (TCM), Sheng-xue-xiaoban, inhibits the angiogenesis in ovarian cancer in vitro

Purpose: The traditional Chinese medicine (TCM), Sheng-xue-xiao-van (SXXB) is reported to be effective in treatment of thrombocytopenic purpura and chemotherapy-induced thrombocytopenia in clinical practices. The purpose of this study was to explore the functions of the SXXB Capsule in ovarian cancer in vitro.Methods: The toxicity of the medicine was measured using CCK8 method in ovarian cancer cell lines A2780 and OC-3-VGH and also the human ovarian epithelial cell line IOSE80. The cells were treated using the DMSO-diluted SXXB solution with the concentration levels at0, 3.125 and 6.25 μg/ml. Western blot was applied to measure the VEGFA proteins in each group. Later, the cells treated with 0 and 25μg/ml SXXB solution for 48h were collected for supernatant. Then HUVECs were co-cultured with the supernatant. Migration and tube formation assays were performed thereafter.Results: SXXB solution showed higher toxicity in ovarian cancer cells than in IOSE80. The protein levels of VEGFA were reduced as the SXXB concentrations increased in ovarian cancer cells but not in IOSE80. Migration and formed tubes were inhibited in HUVECs co-cultured with the supernatant collected from SXXB-treated ovarian cancer cells.Conclusion: The SXXB Capsule might inhibit the angiogenesis in ovarian cancer in vitro.

LncRNA SNHG20 promotes migration and invasion of ovarian cancer via modulating the microRNA-148a/ROCK1 axis

BackgroundOvarian cancer (OC) is characterized by early metastasis and poor prognosis, which threatens the health of women worldwide. Small nucleolar RNA host gene 20 (SNHG20), a long noncoding RNA (lncRNA), has been verified to be significantly up-regulated in several tumors, including OC. MicroRNA-148a (miR-148a)/rho-kinase1 (ROCK1) axis plays an important role in the modulation of tumor development. However, whether SNHG20 can regulate OC progression through miR-148a/ROCK1 axis remains unclear. Normal human ovarian epithelial cell line and four OC cell lines were adopted for in vitro experiments. Real-time PCR was performed to assess the levels of SNHG20 and miR-148a. OC cell proliferation, apoptosis, invasion and migration were detected using clone formation, flow cytometry, transwell, and wound healing assays, respectively. Tumor xenograft assay was applied to evaluate the effect of SNHG20 on tumor growth in vivo.ResultsSignificant higher expression of SNHG20 was observed in OC cell lines. SNHG20 markedly promoted the invasion, migration, proliferation and inhibited the apoptosis of OC cells. SNHG20 enhanced ROCK1 expression by sponging miR-148a, and the direct binding between SNHG20/ROCK1 and miR-148a was identified.ConclusionSNHG20 promoted invasion and migration of OC via targeting miR-148a/ROCK1 axis. The present research may provide a novel insight for the therapeutic strategies of OC.

The Cell-Free Expression of MiR200 Family Members Correlates with Estrogen Sensitivity in Human Epithelial Ovarian Cells.

Exposure to physiological estrogens or xenoestrogens (e.g., zearalenone or bisphenol A) increases the risk for cancer. However, little information is available on their significance in ovarian cancer. We present a comprehensive study on the effect of estradiol, zearalenone and bisphenol A on the phenotype, mRNA, intracellular and cell-free miRNA expression of human epithelial ovarian cell lines. Estrogens induced a comparable effect on the rate of cell proliferation and migration as well as on the expression of estrogen-responsive genes (GREB1, CA12, DEPTOR, RBBP8) in the estrogen receptor α (ERα)-expressing PEO1 cell line, which was not observable in the absence of this receptor (in A2780 cells). The basal intracellular and cell-free expression of miR200s and miR203a was higher in PEO1, which was accompanied with low ZEB1 and high E-cadherin expression. These miRNAs showed a rapid but intermittent upregulation in response to estrogens that was diminished by an ERα-specific antagonist. The role of ERα in the regulation of the MIR200B-MIR200A-MIR429 locus was further supported by publicly available ChIP-seq data. MiRNA expression of cell lysates correlated well with cell-free miRNA expression. We conclude that cell-free miR200s might be promising biomarkers to assess estrogen sensitivity of ovarian cells.

Upregulation of bromodomain PHD finger transcription factor in ovarian cancer and its critical role for cancer cell proliferation and survival.

Bromodomain PHD finger transcription factor (BPTF) is a core subunit of the nucleosome-remodeling factor (NURF) complex, which plays an important role in the development of several cancers. However, it is unknown whether BPTF regulates the progression of ovarian cancer (OC). To investigate this, we measured the relative expression levels of BPTF in OC cell lines and tissues using Western blot and immunohistochemistry, respectively, and the results were analyzed using the χ2 test. We also examined the effects from BPTF knockdown on the proliferation, migration, invasiveness, and apoptosis of OC cell lines. Mechanistic studies revealed that these effects were achieved through simultaneous modulation of multiple signaling pathways. We found that BPTF was highly expressed in OC cell lines and tissues compared with a normal human ovarian epithelial cell line and non-cancerous tissues (P < 0.05). These results are also supported by the public RNA-seq data. BPTF overexpression was correlated with a poor prognosis for OC patient survival (P < 0.05). In vitro experiments revealed that the downregulation of BPTF inhibited OC cell proliferation, colony formation, migration, and invasiveness, and induced apoptosis. BPTF knockdown also affected the epithelial-mesenchymal transition (EMT) signaling pathways and induced the cleavage of apoptosis-related proteins. Consequently, BPTF plays a critical role in OC cell survival, and functions as a potential therapeutic target for OC.

Vinculin presents unfavorable prediction in ovarian cancer and prevents proliferation and migration of ovarian cancer cells.

The influences of Vinculin on many cancers were blurry, including ovarian cancer. Thus, we concentrated on the efficient role of Vinculin in ovarian cancer and explored the potential mechanism(s). Expression of Vinculin in ovarian cancer tissues and cell lines was investigated by real-time polymerase chain reaction, immunohistochemistry, and Western blot. The Kaplan-Meier manner with the logrank was performed to assess overall survival. We further evaluated the relations between Vinculin expression and clinicopathological features of ovarian cancer. Moreover, Vinculin was overexpressed or silenced by respectively transfection with pcDNA-Vinculin or small interfering (si-Vinculin) into human ovarian cancer cell line Caov3 or human ovarian epithelial cell line (HOEpiC). Thereafter, cell viability, cell apoptosis, and migration were checked by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, flow cytometer, and scratch assay, respectively. Likewise, the apoptosis- and migration-related proteins were distinguished by Western blot. Compared to the nontumor tissues or HOEpiC cells, Vinculin was significantly lower expressed in the ovarian cancer tissues and cells. Furthermore, we found out that Vinculin was primarily distributed at the cell membrane and cytoplasm. Moreover, Vinculin was negatively associated with International Federation of Gynecology and Obstetrics stage, grade, and distant metastasis. Overexpression of Vinculin dramatically weakened cell viability and migration and stimulated apoptosis. Conversely, suppression of Vinculin showed opposite results. Vinculin presents unfavorable prediction in ovarian cancer and inhibits ovarian cancer proliferation and migration.

Sinomenine hydrochloride exerts antitumor outcome in ovarian cancer cells by inhibition of long non-coding RNA HOST2 expression

Background Accumulating evidence displays that sinomenine hydrochloride (SH) are utilised to treat a variety of cancers. Nevertheless, the influences of SH on ovarian cancer stay blurry. We endeavoured to uncover the antitumor effects of SH on ovarian cancer and underlying mechanism(s). Methods Human ovarian epithelial cell line (HOEpiC), Caov3 and SKOV3 cells were administrated with SH and/or transfection with pc-long non-coding RNA (lncRNA) human ovarian cancer-specific transcript 2 (HOST2), then cell viability, cell cycle and apoptosis and the related-proteins were respectively inspected by MTT, flow cytometry, and Western blot. In addition, expression of HOST2 was investigated by real-time PCR. Kaplan-Meier manner with the log-rank investigation was achieved to calculate overall survival. Results SH remarkably repressed cell viability, evoked apoptosis and induced cell cycle arrest in G0/G1. Moreover, SH statistically decreased HOST2 expression in Caov3 and SKOV3 cells. Overexpression of HOST2 significantly reversed the effects of SH on Caov3 cell viability, cell cycle and apoptosis. Clinical findings confirmed that HOST2 was profoundly higher expressed in ovarian cancer tissues and cells, and HOST2 predicated unfavourable prognosis of ovarian cancer individuals. Conclusion Our findings recommended that SH exerted the antitumor effect in ovarian cancer cells by hindering expression of HOST2.

Promoter Methylation Down-regulates Osteoprotegerin Expression in Ovarian Carcinoma.

Previous studies have documented that osteoprotegerin (OPG) is involved in the development and progression of several human malignancies. However, OPG has also been shown to act as a tumor suppressor. The aim of this study was to examine the expression status of OPG in ovarian carcinoma cells and investigate the underlying mechanism responsible for alterations in OPG expression. The expression levels of OPG mRNA and protein were assessed in human ovarian carcinoma cell lines. The methylation status of the OPG promoter region was determined using the bisulfite pyrosequencing technique. The effects of demethylation on OPG expression were also analyzed. The human ovarian carcinoma cell lines, SW 626, OVCAR-3, ES-2, TOV-112D, and TOV-21G, expressed significantly lower levels of OPG mRNA and protein than the normal human ovarian epithelial cell line, HS823.Tc. Moreover, three CpG sites in the OPG promoter region were highly methylated in the SW 626, OVCAR-3, ES-2, and TOV-112D ovarian carcinoma cell lines compared to normal control cells. Furthermore, in all the examined ovarian carcinoma cell lines, treatment with the demethylating agent, 5-aza-2-deoxycytidine, resulted in significantly increased expression levels of OPG mRNA and protein compared to the respective pre-treatment levels. OPG expression was down-regulated in the studied ovarian carcinoma cells compared to the normal control cells, while demethylation significantly restored OPG expression in the OPG-down-regulated cell lines. Our results suggest that OPG down-regulation in ovarian carcinoma occurs, at least partly, through epigenetic repression, suggesting its involvement in ovarian carcinogenesis.

Overexpression of the lncRNA FER1L4 inhibits paclitaxel tolerance of ovarian cancer cells via the regulation of the MAPK signaling pathway.

To determine how the lncRNA FER1L4 in ovarian cancer cells influences paclitaxel (PTX) resistance, we examined the expression level of FER1L4 in human ovarian epithelial cell lines IOSE80 and HOSEpiC and human ovarian cancer cell lines OVCAR-3, Caov-3, and SKOV3 through RNA isolation and quantitative polymerase chain reaction (qRT-PCR). SKOV3 cell lines were treated with PTX. The cell survival rate and apoptosis rate of SKOV3 and SKOV3-PR at different PTX dose levels were evaluated. Next, qRT-PCR was performed to detect the expression of FER1L4 in SKOV3 and SKOV3-PR cell lines. SKOV3-PR cell lines were transfected with pcDNA3.1 as the control group (SKOV3-PR/pcDNA3.1) or pcDNA3.1-FER1L4 to upregulate the expression level of FER1L4 (SKOV3-PR/pcDNA3.1-FER1L4). The level of cell survival, apoptosis, and colony formation were compared between the two groups using MTT, flow cytometry analysis, and colony formation assay. To reveal the molecular mechanism, we measured the relative protein phosphorylation level of ERK and MAPK in SKOV3, SKOV3-PR, SKOV3-PR/pcDNA3.1, and SKOV3-PR/pcDNA3.1-FER1L4 groups using an enzyme-linked immunosorbent assay. The effects of SB203580 (a p38 MAPK inhibitor) on PTX were also investigated to reveal the function of the MAPK pathway on the PTX tolerance of SKOV3. In comparison with normal ovarian epithelial cells, FER1L4 was downregulated. The FER1L4 level was decreased in human ovarian cancer cells with drug resistance than in common ovarian cancer cells. The upregulation of FER1L4 could promote the PTX sensitivity of ovarian cancer cells. The increased level of FER1L4 could suppress the PTX resistance of ovarian cancer cells through the inhibition of the MAPK signaling pathway.

Inhibitory effect of nigericin on human epithelial ovarian cancer cells and its mechanism

Objective To ascertain the specific activities of nigericin on inhibiting human epithelial ovarian cancer (EOC) cells, and to investigate the possible molecular mechanism of nigericin on cell migration and invasion. Methods Cell viability under different treatments of nigericin (0.312 5, 0.625, 1.25, 2.5, 5, 10, 20, 40, 80 μmol/L) on EOC A2780 and SKOV3 cell lines was examined by CCK-8 assay, with DMSO as a control. The human epithelial ovarian cancer cell lines A2780 and SKOV3 were treated with 5, 10 or 20 μmol/L nigericin or with DMSO as a control. Transwell chambers was used to observe the impact of nigericin on migration and invasion of EOC cells. Western blot was used to detect the expressions of epithelial cell marker (E-cadherin), mesenchymal cell marker (Vimentin) and the epithelial-mesenchymal transition (EMT)-related transcription factors Slug, Snail, and Twist, as well as the expressions of proteins related to Wnt/β-catenin signaling pathway such as Gsk-3β, p-Gsk-3β and β-catenin under different concentration treatment of nigericin. Results CCK-8 assay showed that nigericin exhibited strong cytotoxicity on A2780 [IC50 (16.19±0.26) μmol/L, 95% CI 1.077-1.341)] and SKOV3 [IC50 (11.87±0.21) μmol/L, 95% CI 1.003-1.146] cell lines. Transwell chamber assay revealed that nigericin at different concentration (5, 10, 20 μmol/L) induced a remarkable reduction in the number of cells migrating through the membrane relative to the vehicle-treated controls in A2780 and SKOV3 cells [(121±9), (92±7), (59±5)/HP and (120.4±2.6), (91.8±5.5), (80.0±4.0)/HP, all P < 0.05]; the invasive ability of A2780 and SKOV3 cells also inhibited [(61.2±3.7), (43.2±4.3), (23.6±2.1)/HP and (85.2±7.0), (65.2±4.6), (45.6±4.4)/HP, all P < 0.05]. Western blot revealed that the increased expression of E-cadherin and decreased expression of Vimentin, Slug, Snail, Twist, p-Gsk-3β, β-catenin in EOC cells with the nigericin treatment at different concentration (5, 10 and 20 μmol/L) showed concentration dependence (P < 0.05). Conclusion Nigericin may induce EMT by activating Wnt-β-catenin signaling pathway to promote the migration and invasion of EOC cells. Key words: Ovarian neoplasms; Nigericin; Epithelial-mesenchymal transition; Migration; Invasion

MicroRNA-142-3p inhibits cell proliferation and chemoresistance in ovarian cancer via targeting sirtuin 1.

MicroRNAs (miRs) serve promoting or suppressive roles in various human cancer types, including ovarian cancer; however, the role of miR-142-3p in ovarian cancer growth and chemoresistance has not previously been studied. In the present study, reverse transcription-quantitative polymerase chain reaction and western blotting were used to examine miR and protein expression levels. An MTT assay was used to examine cell proliferation. A luciferase reporter gene assay was used to clarify the target gene of miR-142-3p. The present study reported that miR-142-3p expression levels were significantly lower in ovarian cancer tissues and cell lines, when compared with those in adjacent tissues and the normal human ovarian epithelial cell line IOSE386, respectively. The reduced expression of miR-142-3p was significantly associated with poor cell differentiation. Ectopic expression of miR-142-3p significantly inhibited the proliferation of ovarian cancer cells and increased the sensitivity of SKOV3/DDP cells to cisplatin. Sirtuin 1 (SIRT1) was identified as a target gene of miR-142-3p; SIRT1 expression was negatively regulated by miR-142-3p in ovarian cancer cells. Further investigation demonstrated that SIRT1 reversed the suppressive effects of miR-142-3p on the proliferation and chemoresistance of ovarian cancer cells. In addition, SIRT1 was significantly upregulated in ovarian cancer. A negative correlation between the expression of SIRT1 and miR-142-3p in ovarian cancer tissues was also observed. In summary, the present study indicated that miR-142-3p inhibits the proliferation and chemoresistance of ovarian cancer cells by targeting SIRT1. This suggests that miR-142-3p may be a promising therapeutic candidate for the treatment of ovarian cancer.

Long non-coding RNA MALAT1 is upregulated and involved in cell proliferation, migration and apoptosis in ovarian cancer.

Ovarian cancer (OC) is the leading cause of mortality among gynecological malignancies. Although microRNAs are known to have a key regulatory role in OC, the involvement of long non-coding RNAs in the disease is less established. Previous studies have demonstrated that metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a tumor oncogene in many cancers, though its role in OC remains unclear. The present study reported that MALAT1 expression was markedly upregulated in OC, by knockdown of MALAT1 expression in vivo, using RNA interference (RNAi) with small-interfering RNA (siRNA). It was found that MALAT1 expression was positively correlated with the International Federation of Gynecology and Obstetrics stages of OC, tumor histological grade and lymph node metastasis. In addition, the differential MALAT1 levels between a human ovarian epithelial cell line (HOSE) and OC cell lines (ES-2, OVCAR3, SKOV3 and HO8910) were compared in vitro. Notably, MALAT1 was expressed to a high level in OC cells. Furthermore, exogenous knockdown of MALAT1 significantly repressed growth and migration of OC cells, and promoted their apoptosis. Collectively, the current findings suggest that upregulation of MALAT1 in OC may facilitate tumorigenesis and metastasis. Knockdown of MALAT1 expression has potential as a novel target for the diagnosis and therapy of OC.

Loss of HDAC-Mediated Repression and Gain of NF-κB Activation Underlie Cytokine Induction in ARID1A- and PIK3CA-Mutation-Driven Ovarian Cancer

ARID1A is frequently mutated in ovarian clear cell carcinoma (OCCC) and often co-exists with activating mutations of PIK3CA. Although induction ofpro-inflammatory cytokines has been observed in this cancer, the mechanism by which the two mutations synergistically activate cytokine genes remains elusive. Here, we established an invitro model of OCCC by introducing ARID1A knockdown and mutant PIK3CA into a normal human ovarian epithelial cell line, resulting in cell transformation and cytokine gene induction. We demonstrate that loss of ARID1A impairs the recruitment of the Sin3A-HDAC complex, while the PIK3CA mutation releases RelA from IκB, leading to cytokine gene activation. We show that an NF-κB inhibitor partly attenuates the proliferation of OCCC and improves the efficacy of carboplatin both in cell culture and in a mouse model. Our study thus reveals the mechanistic link between ARID1A/PIK3CA mutations and cytokine gene induction in OCCC and suggests that NF-κB inhibition could be a potential therapeutic option.

The molecular mechanism of action of superactive human leptin antagonist (SHLA) and quadruple leptin mutein Lan-2 on human ovarian epithelial cell lines.

IntroductionA number of leptin receptor antagonists have been synthesised for therapeutic use, with pre-clinical tests suggesting their future use in anticancer therapy. To our knowledge, there are no data concerning the possible application of leptin receptor blockers in ovarian cancer.MethodsIn this study, we evaluated two leptin receptor antagonists: superactive human leptin antagonist (SHLA) and quadruple leptin mutein, Lan-2 (L39A/D40A/F41A/I42A), on cell proliferation (Alamar Blue test, BrdU assay), cell cycle gene (qPCR) and protein expression (Western blot) and cell signalling pathways (Western blot) in three different types of cell lines: OVCAR-3, CaOV-3 and HOSEpiC.ResultsBoth receptor blockers had no effect on non-cancerous HOSEpiC cell line proliferation; however, both reversed the stimulatory effect of leptin on CaOV-3 cell line proliferation to control levels and to below control levels in OVCAR-3 cells. In metastatic carcinoma CaOV-3, both ObR antagonists had an inhibitory effect on the cdk2/cyclin D1 complex, while in serous carcinoma, OVCAR-3, they only had an effect on cdk2 and cdk4 protein expression. SHLA had an inhibitory effect on all investigated signalling pathways in OVCAR-3, while only on Stat3 in CaOV-3. Lan-2 had an inhibitory effect on Stat3 and ERK1/2 in CaOV-3, while in OVCAR-3 it only affected Akt protein phosphorylation.ConclusionBased on these results, we conclude that SHLA and Lan-2 are promising leptin receptor inhibitors which could be used to block leptin activity, eliminating its negative effects on activities related to carcinogenesis. However, the selection of a specific antagonist should be related to tumour type.

Apoptotic effects of salinomycin on human ovarian cancer cell line (OVCAR-3).

In this study, we studied the apoptotic and cytotoxic effects of salinomycin on human ovarian cancer cell line (OVCAR-3) as salinomycin is known as a selectively cancer stem cell killer agent. We used immortal human ovarian epithelial cell line (IHOEC) as control group. Ovarian cancer cells and ovarian epithelial cells were treated by different concentrations of salinomycin such as 0.1, 1, and 40μM and incubated for 24, 48, and 72h. Dimethylthiazol (MTT) cell viability assay was performed to determine cell viability and toxicity. On the other hand, the expression levels of some of the apoptosis-related genes, namely anti-apoptotic Bcl-2, apoptotic Bax, and Caspase-3 were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, Caspase-3 protein level was also determined. As a result, we concluded that incubation of human OVCAR-3 by 0.1μM concentration of salinomycin for 24h killed 40% of the cancer cells by activating apoptosis but had no effect on normal cells. The apoptotic Bax gene expression was upregulated but anti-apoptotic Bcl-2 gene expression was downregulated. Active Caspase-3 protein level was increased significantly (p < 0.05).

Knockdown of eIF4E suppresses cell proliferation, invasion and enhances cisplatin cytotoxicity in human ovarian cancer cells.

Eukaryotic initiation factor 4E (eIF4E) plays an important role in cap-dependent translation. The overexpression of eIF4E gene has been found in a variety of human malignancies. In this study, we attempted to identify the potential effects of eIF4E and explore the possibility of eIF4E as a therapeutic target for the treatment of human ovarian cancer. First the activation of eIF4E protein was detected with m7-GTP cap binding assays in ovarian cancer and control cells. Next, the eIF4E-shRNA expression plasmids were used to specifically inhibit eIF4E activity in ovarian cancer cells line A2780 and C200. The effects of knockdown eIF4E gene on cell proliferation, migration and invasion were investigated in vitro. Moreover, the changes of cell cycle and apoptosis of ovarian cancer cells were detected by flow cytometry. Finally, we investigated the effect of knockdown of eIF4E on the chemosensitivity of ovarian cancer cells to cisplatin in vitro. Our results show there is elevated activation of eIF4E in ovarian cancer cells compared with normal human ovarian epithelial cell line. The results of BrdU incorporation and FCM assay indicate that knockdown of eIF4E efficiently suppressed cell growth and induce cell cycle arrest in G1 phase and subsequent apoptosis in ovarian cancer cells. From Transwell assay analysis, knockdown eIF4E significantly decrease cellular migration and invasion of ovarian cancer cells. We also confirmed that knockdown eIF4E could synergistically enhance the cytotoxicity effects of cisplatin to cancer cells and sensitized cisplatin-resistant C200 cells in vitro. This study demonstrates that the activation of eIF4E gene is an essential component of the malignant phenotype in ovarian cancer, and aberration of eIF4E expression is associated with proliferation, migration, invasion and chemosensitivity to cisplatin in ovarian cancer cells. Knockdown eIF4E gene can be used as a potential therapeutic target for the treatment of human ovarian cancer.