Up-regulation of circ_LARP4 suppresses cell proliferation and migration in ovarian cancer by regulating miR-513b-5p/LARP4 axis.

BACKGROUND: Ovarian cancer (OC) is a common fatal malignant tumor of female reproductive system worldwide. Growing studies have proofed that circular RNAs (circRNAs) engage in the regulation of various types of cancers. However, the underlying biological functions and effect mechanism of circular RNA_LARP4 (circ_LARP4) in OC have not been explored. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was used to detect the expression of circ_LARP4 in OC cells. The function of circ_LARP4 was measured by cell counting kit-8 (CCK-8), colony formation assay and transwell assay. RNA immunoprecipitation (RIP) assay and luciferase reporter assays assessed the binding correlation between miR-513b-5p and circ_LARP4 (or LARP4). RESULTS: The expression of circ_LARP4 in OC cells was much lower than that in human normal ovarian epithelial cells. Overexpressing circ_LARP4 impaired cell proliferation, invasion and migration abilities. Circ_LARP4 worked as a competing endogenous RNA (ceRNA) to sponge miR-513b-5p. Furthermore, LARP4 was indirectly modulated by circ_LARP4 as the downstream target of miR-513b-5p, as well as the host gene of circ_LARP4. CONCLUSION: Circ_LARP4 could hamper cell proliferation and migration by sponging miR-513b-5p to regulate the expression of LARP4. This research may provide some referential value to OC treatment.

Down-regulation of p16 and MGMT promotes the anti-proliferative and pro-apoptotic effects of 5-Aza-dC and radiation on cervical cancer cells.

Cervical cancer is one of the most common malignancies of the female reproductive system. Therefore, it is critical to investigate the molecular mechanisms involved in the development and progression of cervical cancer. In this study, we stimulated cervical cancer cells with 5-aza-2'-deoxycytidine (5-Aza-dC) and found that this treatment inhibited cell proliferation and induced apoptosis; additionally, methylation of p16 and O-6-methylguanine-DNA methyltransferase (MGMT) was reversed, although their expression was suppressed. 5-Aza-dC inhibited E6 and E7 expression and up-regulated p53, p21, and Rb expression. Cells transfected with siRNAs targeting p16 and MGMT as well as cells stimulated with 5-Aza-dC were arrested in S phase, and the expression of p53, p21, and Rb was up-regulated more significantly. However, when cells were stimulated with 5-Aza-dC after transfection with siRNAs targeting p16 and MGMT, proliferation decreased significantly, and the percentage of cells in the sub-G1 peak and in S phase was significantly increased, suggesting a marked increase in apoptosis. But E6 and E7 overexpression could rescue the observed effects in proliferation. Furthermore, X-ray radiation caused cells to arrest in G2/M phase, but cells transfected with p16- and MGMT-targeted siRNAs followed by X-ray radiation exhibited a significant decrease in proliferation and were shifted toward the sub-G1 peak, also indicating enhanced apoptosis. In addition, the effects of 5-Aza-dC and X-ray radiation were most pronounced when MGMT expression was down-regulated. Therefore, down-regulation of p16 and MGMT expression enhances the anti-proliferative effects of 5-Aza-dC and X-ray radiation. This discovery may provide novel ideas for the treatment of cervical cancer.

Radix ranunculus temate saponins sensitizes ovarian cancer to Taxol via upregulation of miR-let-7b.

A common cause of treatment failure in ovarian cancer is acquired drug resistance. Therefore, effective novel drugs against chemoresistance need to be developed. MicroRNAs (miRNAs or miRs) serve key regulatory roles in tumorigenesis and chemoresistance. The objective of the present study was to explore the role of miR-let-7b in ovarian cancer chemoresistance, and to develop novel strategy for the treatment of drug-resistant ovarian cancer. For this purpose, reverse transcription-quantitative PCR was performed to evaluate the expression level of miR-let-7b in fresh ovarian cancer tissues and cell lines. miR-let-7b mimic was transfected into ovarian cancer cell lines. Functional experiments, cell apoptosis and cell viability assays were carried out to identify the tumor-suppressor function of miR-let-7b. The treatment effect of Radix ranunculus temate saponins (RRTS), one of the primary constituents extracted from the traditional Chinese medicine radix Ranunculi ternati, was identified in vitro and in vivo. The results revealed that miR-let-7b was downregulated significantly in chemoresistant ovarian cancer patients. miR-let-7b overexpression suppressed cell growth and invasion and enhanced sensitivity to Taxol of ovarian cancer cells. Furthermore, miR-let-7b levels in ovarian cancer tissue were inversely associated with collagen type III α1 chain (COL3A1) levels. COL3A1, a non-fibrillar collagen associated with chemoresistance, was targeted by miR-let-7b. RRTS showed cytotoxic effects on ovarian cancer cells through inducing miR-let-7b expression and decreasing COL3A1 expression. In addition, RRTS sensitized ovarian cancer to Taxol both in vitro and in vivo. In conclusion, the present results revealed synergistic cytotoxicity of RRTS and Taxol on against ovarian cancer cells via upregulating expression of miR-let-7b. Combination of Taxol and RRTS may be a novel treatment strategy for patients with TR ovarian cancer.

Overexpression of glycosyltransferase 8 domain containing 2 confers ovarian cancer to CDDP resistance by activating FGFR/PI3K signalling axis.

It has been reported that chemotherapy resistance mainly contributed to treatment failure and poor survival in patients with ovarian cancer. Therefore, clarifying the molecular mechanism and identifying effective strategies to overcome drug resistance may play an important clinical impact on this malignant tumor. In our study, we found that the expression of Glycosyltransferase 8 domain containing 2 (GLT8D2) was significantly upregulated in ovarian cancer samples with CDDP (Cis-dichlorodiammine-platinum) resistance. Biological experiment demonstrate that GLT8D2 overexpression confers CDDP resistance on ovarian cancer cells; however, inhibition of GLT8D2 sensitized ovarian cancer cell lines to CDDP cytotoxicity both in vitro and in vivo. By using affinity purification/mass spectrometry (IP/MS) and reciprocal co-immunoprecipitation (co-IP) analyses, we found that GLT8D2 interacts with fibroblast growth factor receptor 1(FGFR1) in ovarian cancer cells. Furthermore, overexpression of GLT8D2 activated FGFR/PI3K signaling axis and upregulated the phosphorylation levels of FRS2a and AKT (AKT serine/threonine kinase). Importantly, pharmacological inhibition of FGFR and PI3K (phosphatidylinositol 3-kinase) signaling pathway significantly counteracted GLT8D2-induced chemoresistance and enhanced platinum's therapeutic efficacy in ovarian cancer. Therefore, our findings suggest that GLT8D2 is a potential therapeutic target for the treatment of ovarian cancer; targeting GLT8D2/FGFR/PI3K/AKT signaling axis may represent a promising strategy to enhance platinum response in patients with chemoresistant ovarian cancer.

Elevated MYO10 Predicts Poor Prognosis and its Deletion Hampers Proliferation and Migration Potentials of Cells Through Rewiring PI3K/Akt Signaling in Cervical Cancer.

MYO10, recognized as an important regulator of cytoskeleton remodeling, has been reported to be associated with tumorigenesis. However, its functional implication in cervical cancer and potential mechanism still remain to be undetermined currently. MYO10 level in cervical cancer tissues was analyzed by using data retrieved from The Cancer Genome Atlas and ONCOMINE databases. Messenger RNA and protein expression levels were determined by quantitative real-time polymerase chain reaction and Western blotting. Small-interfering RNA and overexpressing plasmid were used for MYO10 silencing and overexpression, and cell proliferation was analyzed by CCK-8. Transwell assays were performed to investigate the ability of cell migration and invasion. MYO10 was upregulated in cervical cancer tissues and cells when compared to normal controls, and survival analysis showed patients with high MYO10 expression had worse overall survival. Moreover, knockdown/overexpression of MYO10 significantly inhibited/enhanced the proliferation, invasion, and migration capabilities of cervical cells transfected with siRNAs/overexpressing plasmid. Additionally, MYO10 silencing inhibited PI3K/Akt signaling pathway by decreasing the phosphorylation status of PI3K and AKT. Data from the present study indicated that MYO10 were overexpressed in patients with cervical cancer and positively linked with poor prognosis. Experimental results suggested that MYO10 induced a significant encouraging effect in cervical cancer cell proliferation, invasion, and migration, linked with involvement of PI3K/Akt signaling. Collectively, these results emphasize a novel role for MYO10 overexpression in cervical cancer and provide a potent therapeutic strategy against cervical cancer.

Lymph node ratio may predict the benefit of postoperative radiotherapy in node-positive cervical cancer.

The standard treatment for node-positive cervical cancer after radical hysterectomy is pelvic radiotherapy and concurrent chemotherapy. Given the potential toxicity of postoperative radiotherapy, we used the lymph node ratio (LNR) to assess the benefit of postoperative radiotherapy in lymph node-positive cervical cancer patients. Data from the Surveillance Epidemiology and End Results database (1988-2010) were analyzed using Kaplan-Meier and Cox regression proportional hazard analysis. A total of 2,269 eligible patients were identified (median follow-up, 78.0 months); 1,863 (82.1%) patients received postoperative radiotherapy. In both univariate and multivariate analysis multivariate analysis, a higher LNR was significantly associated with a poorer outcome. A LNR > 0.16 was associated with poorer cervical cancer-related survival (CCSS) (hazard Ratio [HR] 1.376, confidence interval [CI] 1.082-1.750; P < 0.001) and overall survival (OS) (HR 1.287, CI 1.056-1.569; P = 0.012). Postoperative radiotherapy was only associated with survival benefits in patients with a LNR > 0.16 (CCSS, P < 0.001; OS, P < 0.001) and not in patients with a LNR ≤ 0.16 (CCSS, P = 0.620; OS, P = 0.167); these trends were not affected by number of removed lymph nodes. A higher LNR is associated with a poorer survival in lymph node-positive cervical cancer. The survival benefits of postoperative radiotherapy appear to be limited to patients with a LNR > 0.16.