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BACKGROUND: Long non-coding RNAs (lncRNAs) play critical roles in the occurrence and progression of various tumors, including ovarian cancer (OC). The lncRNA growth arrest-specific transcript 5 (GAS5) has been shown to be an important modulator in the growth and metastasis of OC cells. Our previous studies confirmed that GAS5 was down-regulated in OC; however, the potential underlying molecular mechanism underlying has not yet been elucidated. METHODS: We screened the Gene Expression Profiling Interactive Analysis (GEPIA) database for the expression of the lncRNA GAS5 in OC. Cell Counting Kit-8 (CCK-8), transwell assay, colony formation assay, flow cytometry analysis, and western blotting were applied to determine the various functions of GAS5 in OC progression. The competing endogenous RNA (ceRNA) mechanism was verified through bioinformatics analysis, dual-spectral luciferase reporter gene assay, and RNA immunoprecipitation assay (RIPA). Finally, the expression interactions between microRNA-96-5p, phosphatase and tensin homolog deleted on chromosome ten (PTEN), and GAS5 were measured. RESULTS: Our results demonstrated decreased expression levels of GAS5 and PTEN in OC samples and cell lines, while miR-96-5p was up-regulated when compared with the controls. GAS5 overexpression could significantly reduce OC cell proliferation and invasion ability via suppression of miR-96-5p expression. Moreover, GAS5 could influence the PTEN/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. CONCLUSIONS: Our study identified GAS5 as a ceRNA that can regulate the PTEN/AKT/mTOR axis by sponging miR-96-5p in OC.

Background Long non-coding RNAs (lncRNAs) play vital roles in the development and progression of non-small-cell lung cancer (NSCLC); however, the role of most lncRNAs in NSCLC remains unknown. This study explored the clinical significance, biological function and underlying mechanism of lnc-GAN1 in NSCLC. Methods With a custom lncRNA microarray we found that lnc-GAN1 is markedly downregulated in NSCLC tissues. Then lnc-GAN1 expression level was measured using qRT-PCR in NSCLC tissues and cell lines. Survival was assessed using the Kaplan-Meier method. The biological functions of lnc-GAN1 in lung cancer cells were evaluated in vitro and in vivo. RNA fluorescence in situ hybridization and subcellular localization assays revealed the subcellular distribution of lnc-GAN1 in cells. Bioinformatic analysis was adopted to predict miRNAs and signaling pathways regulated by lnc-GAN1. RNA immunoprecipitation and Dual-luciferase reporter assays were used to assess the interaction between lnc-GAN1 and miR-26a-5p in lung cancer cells. Results lnc-GAN1 is downregulated in HCC tissues and associated with larger tumor size and poor overall survival and disease-free survival; its ectopic expression suppresses cell proliferation, colony formation, and cell cycle progression and induces apoptosis in NSCLC cells; it also inhibits tumor growth in the NSCLC xenograft model. We further proved that lnc-GAN1 is localized in cytoplasm and transcribed independently from its parental gene GAN. Mechanistically, lnc-GAN1 acts as a sponge for miR-26a-5p by two seed sequences, and the two non-coding RNAs have a negative relationship in NSCLC tissues; we further prove that PTEN is a direct target of miR-26a-5p and lnc-GAN1 inhibits cell cycle signaling pathway by activating PTEN, whose expression level correlated negatively with miR-26a-5p level but positively with lnc-GAN1 level in NSCLC samples. Conclusions Lnc-GAN1 is downregulated and associated with poor survival of NSCLC patients, and mechanistically acts as a tumor suppressor via sponging and inhibiting miR-26a-5p to upregulate PTEN. This study provides a potential prognostic biomarker and treatment target for NSCLC.

Follicle-stimulating hormone (FSH) is closely related to the pathogenesis and progression of epithelial ovarian cancer (EOC). However, until now, knowledge relating to FSH-driven signalling pathways that lead to the growth of EOC remained incomplete. We sought to explore whether sphingosine kinase (SphK) could mediate FSH-induced ovarian cancer cell proliferation and which pathway might be involved in this process. The expression of phospho-SphK1 and phospho-SphK2 was detected in sections of EOC tissues by Immunohistochemical staining, and clinical significances were analyzed by statistical analysis. EOC cells were treated with FSH or/and SKI-II. CCK8 assays and colony formation assays were used to investigate cell proliferation. Western blot was carried out to detect protein expression in EOC cell line after treated with FSH. Here, for the first time, we provide evidence that high expression levels of phospho-SphK1 and phospho-SphK2 were both prognostic indicators of overall survival (OS) in EOC. Additionally, the expression levels of both phospho-SphK1 and phospho-SphK2 were closely correlated with the expression level of follicle-stimulating hormone receptor (FSHR) in ovarian cancer tissues. FSH stimulated the phosphorylation of both SphK1 and SphK2 and was able to regulate the survival and growth of ovarian cancer cells by activating SphK1 and SphK2 through ERK1/2. Both isoenzymes of SphK were equally responsible for FSH-induced cell proliferation of EOC. Both Erk1/2 and Akt activation play important roles in mediating FSH-induced cell proliferation after phosphorylation of SphK. Moreover, our data demonstrated that S1P receptor 1 (S1PR1) and S1PR3, key components of the SphK signalling system, were involved in FSH-mediated proliferation of EOC. Taken together, the results of the current study revealed that SphK is an essential mediator in FSH-induced proliferation of ovarian cancer cells in EOC, which indicates a new signalling pathway that controls FSH-mediated growth in EOC and suggests a new strategy that pharmaceutically targets both isoenzymes of SphK for the management of ovarian cancer.

Background:This study aims to identify a long non-coding RNA (lncRNA) signature for predicting survival in non-small-cell lung carcinoma (NSCLC) patients and providing additional prognostic information to the tumor node metastasis (TNM) staging system. Methods: NSCLC cases from a hospital were divided into a discovery cohort (n=194) and validation cohort (n=172) and analyzed using a custom lncRNA microarray. Another 73 cases obtained from another hospital were assayed using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The differentially expressed lncRNAs were detected by significance analysis of microarrays (SAM) program and used for identifying those associated with survival in the discovery cohort, which were then employed to construct a prognostic lncRNA signature using a risk-score method. The signature was then confirmed in the validation and independent cohort as well. Results: The discovery cohort was found to comprise of 305 lncRNAs, which showed differential expression between the NSCLC and the corresponding normal lung tissues, a 4-lncRNA signature was identified that was found to significantly correlate with the survival of the NSCLC patients. This signature was further validated in the validation and independent cohort. Moreover, multivariate Cox analysis demonstrates that the 4-lncRNA signature is independent of the TNM staging system.as a risk-score model. The receiver operating characteristic (ROC) curve indicates that the prognostic value of the combined model is significantly higher than that of TNM staging alone in all the cohorts. Conclusions:This study identified a 4-lncRNA signature, which is a powerful prognostic biomarker which related to patient survival in addition to the traditional TNM staging system.

Background Epithelial ovarian cancer (EOC) is the malignant tumor of the female reproductive system with the highest fatality rate. Tolerance of chemotherapeutic drugs like cisplatin (DDP) occurring in very early stage is one of the important factors of the poor prognosis of epithelial ovarian cancer. Here we aim to study the dysregulation of a particular long noncoding RNA, lncRNA GAS5, and its role in EOC progression. Methods The low expression of lncRNA GAS5 in EOC tissues and OC cell lines was determined by microarray analyses and Real-Time qPCR. Flow cytometer assays were used to detect cell cycle and apoptosis of OC cells. CCK8 assay were performed to investigate the DDP sensitivity of OC cells. Western blot was carried out to detect cell growth markers, apoptotic markers, PARP1, E2F4, MAPK pathway protein expression and other protein expression in OC cell lines. The binding of GAS5 and E2F4 were proved by RNA pull-down and RIP assay. The effect of E2F4 on PARP1 were determined by CHIP-qPCR assay and luciferase reporter assay. The effect of lncRNA GAS5 on OC cells was assessed in vitro and in vivo. Results By microarray (3 EOC tissues νs. 3 normal ovary tissues) and RT- qPCR (53 EOC tissues νs. 10 normal ovary tissues) we identified lncRNA GAS5 to be dramatically low expressed in EOC samples and correlated with prognosis. Compared with sensitive cell lines, GAS5 was also low expressed in DDP resistant OC cell lines, and over-expression of GAS5 significantly enhanced the sensitivity of OC cells to DDP in vivo and in vitro. Meanwhile the over-expression of GAS5 also caused OC cells G0/G1 arrest and apoptosis increase. Mechanistically, GAS5 might regulate PARP1 expression by recruiting the transcription factor E2F4 to its promoter, and then affect the MAPK pathway activity. Due to the 5’TOP structure, GAS5 could be regulated by transcription inhibitor rapamycin in OC cells. Conclusion Here we explored the specific mechanisms of EOC cisplatin resistance and tumor progress due to lncRNA-GAS5, presented the GAS5-E2F4-PARP1-MAPK axis and its role in OC drug-sensitivity and progression for the first time, and the results may provide experimental basis for clinical application.

Aims This retrospective study was carried out to compare the outcomes between elderly (≥70 years of age) and nonelderly patients (