Long non-coding RNA SNHG15 interacts with and stabilizes transcription factor Slug and promotes colon cancer progression

SNHG15 functions as a tumor suppressor in thyroid cancer

Small nucleolar RNA host gene 15 (SNHG15) has been suggested to be overexpressed, and function as an oncogenic long noncoding RNA (lncRNA) in various types of human malignancies. However, the expression status and function of SNHG15 were still unknown in thyroid cancer. In our study, we assessed the expression status and clinical value in thyroid cancer samples, and explored the effect of SNHG15 on thyroid cancer cell proliferation, migration, and invasion. In results, SNHG15 expression was downregulated in thyroid cancer tissues and cells, and correlated with age, pathology classification, clinical stage, tumor size, distant metastasis, and disease-free survival. The in vitro studies suggested SNHG15 overexpression suppressed cell proliferation, migration, and invasion in thyroid cancer. In summary, SNHG15 serves as tumor suppressive role in thyroid cancer.

Long noncoding RNA SNHG15 serves as an oncogene and predicts poor prognosis in epithelial ovarian cancer

Objective

This study aims to investigate the functional role of long noncoding RNA SNHG15 in epithelial ovarian cancer (EOC).

Materials and methods

The expression of SNHG15 was measured in EOC cells and tissues using qRT-PCR. The correlation of SNHG15 expression and the clinicopathological characters was statistically analyzed. The prognosis of patients with different clinical features in the high/low SNHG15 expression groups were calculated. Moreover, univariate and multivariate Cox regression analyses were performed to identify the risk factors for poor overall survival (OS) and progression-free survival (PFS). The effect of SNHG15 on the migration and invasion was evaluated using Transwell and Matrigel, respectively. The proliferation ability of EOC cells was tested using colony formation and MTT assay. The influence of SNHG15 on the cisplatin resistance was detected by measuring cell inhibition rate and cell viability.

Results

SNHG15 was upegulated in EOC cells and tissues. High SNHG15 expression was correlated with EOC progression and predicted poor OS and PFS in different subgroups of EOC patients. Moreover, multivariate Cox regression analysis defined high SNHG15 expression as an independent risk factor for poor OS and PFS. Furthermore, functional assays showed that the overexpression of SNHG15 promoted migration and invasion, while the loss of SNHG15 suppressed migration and invasion. Furthermore, the proliferation of EOC cells was improved after the ectopic expression of SNHG15, which was suppressed with SNHG15 deficiency. In addition, cisplatin-resistant EOC cells were established for detecting the effect of SNHG15 on EOC chemoresistance. The results showed that cisplatin-resistant EOC cells exhibited much higher levels of SNHG15 expression than controls, and SNHG15 contributed to the chemoresistance of EOC cells.

Conclusion

This study confirms that SNHG15 contributes to the migration, invasion, proliferation, and chemoresistance of EOC. SNHG15 may serve as a potential therapeutic target and prognostic biomarker of EOC patients.

Epigenetic Regulation by lncRNAs: An Overview Focused on UCA1 in Colorectal Cancer

Colorectal cancers have become the second leading cause of cancer-related deaths. In particular, acquired chemoresistance and metastatic lesions occurring in colorectal cancer are a major challenge for chemotherapy treatment. Accumulating evidence shows that long non-coding (lncRNAs) are involved in the initiation, progression, and metastasis of cancer. We here discuss the epigenetic mechanisms through which lncRNAs regulate gene expression in cancer cells. In the second part of this review, we focus on the role of lncRNA Urothelial Cancer Associated 1 (UCA1) to integrate research in different types of cancer in order to decipher its putative function and mechanism of regulation in colorectal cancer cells. UCA1 is highly expressed in cancer cells and mediates transcriptional regulation on an epigenetic level through the interaction with chromatin modifiers, by direct regulation via chromatin looping and/or by sponging the action of a diversity of miRNAs. Furthermore, we discuss the role of UCA1 in the regulation of cell cycle progression and its relation to chemoresistance in colorectal cancer cells.

Identification of key lncRNAs in the carcinogenesis and progression of colon adenocarcinoma by co-expression network analysis

Colon adenocarcinoma (COAD) is one of the most common cancers, and its carcinogenesis and progression is influenced by multiple long non-coding RNAs (lncRNA), especially through the miRNA sponge effect. In this study, more than 4000 lncRNAs were re-annotated from the microarray datasets through probe sequence mapping to obtain reliable lncRNA expression profiles. As a systems biology method for describing the correlation patterns among genes across microarray samples, weighted gene co-expression network analysis was conducted to identify lncRNA modules associated with the five stepwise stages from normal colonic samples to COAD (n = 94). In the most relevant module (R²  = -0.78, P = 4E-20), four hub lncRNAs were identified (CTD-2396E7.11, PCGF5, RP11-33O4.1, and RP11-164P12.5). Then, these four hub lncRNAs were validated using two other independent datasets including GSE20916 (n = 145) and GSE39582 (n = 552). The results indicated that all hub lncRNAs were significantly negatively correlated with the three-stage colonic carcinogenesis, as well as TNM stages in COAD (one-way analysis of variance P < 0.05). Kaplan-Meier survival curve showed that patients with higher expression of each hub lncRNA had a significantly higher overall survival rate and lower relapse risk (log-rank P < 0.05). In conclusion, through co-expression analysis, we identified and validated four key lncRNAs in association with the carcinogenesis and progression of COAD, and these lncRNAs might have important clinical implications for improving the risk stratification, therapeutic decision and prognosis prediction in COAD patients.

LncRNA SNHG15 acts as a ceRNA to regulate YAP1-Hippo signaling pathway by sponging miR-200a-3p in papillary thyroid carcinoma

Over the past decade, lncRNAs have been widely reported in human malignant tumors, including papillary thyroid carcinoma. LncRNA SNHG15 has been validated to be a tumor facilitator in several types of malignancies. The present study focused on the biological role of SNHG15 in papillary thyroid carcinoma. Based on the result of qPCR analysis, we identified the strong expression of SNHG15 in human papillary thyroid carcinoma tissues and cell lines. Moreover, Kaplan–Meier method was utilized to analyze the internal relevance between SNHG15 expression and overall survival rate of patients with papillary thyroid carcinoma. Loss-of-function assays were designed and conducted to determine the inhibitory effects of silenced SNHG15 on the cell growth and migration in papillary thyroid carcinoma. The mechanical investigation indicated that SNHG15 upregulated YAP1 by sponging miR-200a-3p. Moreover, results of gain-of-function assays validated the anti-oncogenic function of miR-200a-3p in papillary thyroid carcinoma. Finally, results of rescue assays validated the function of SNHG15-miR-200a-3p-YAP1 axis in papillary thyroid carcinoma. YAP1 is known as an oncogene and a core factor of Hippo pathway. Here, we demonstrated that SNHG15 inactivated Hippo signaling pathway in papillary thyroid carcinoma. In summary, our findings demonstrated that SNHG15 serves as a competitively endogenous RNA (ceRNA) to regulate YAP1-Hippo signaling pathway by sponging miR-200a-3p in papillary thyroid carcinoma.

Long noncoding RNA MALAT1 regulates HDAC4-mediated proliferation and apoptosis via decoying of miR-140-5p in osteosarcoma cells

Noncoding RNAs regulate the initiation and progression of osteosarcoma (OS). The role of long noncoding RNA metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1) playing in OS and whether the function it working out was achieved through HDAC4 pathway remain uncovered. In this study, we illustrated that MALAT1 was upregulated and was correlated with poor prognosis in OS patients. Meanwhile, we demonstrated that a depression of MALAT1 suppressed proliferation and promoted apoptosis in OS cell line HOS and 143B. Further, we verified that MALAT1 exerting its function via upregulating of histone deacetylase 4 (HDAC4). Through an online prediction, a series of luciferase assays and RNA pull‐down assays, we demonstrated that both MALAT1 and HDAC4 were the targets of microRNA‐140‐5p (miR‐140‐5p) via sharing a similar microRNA responding elements. Even further, we revealed that MALAT1 served as a ceRNA of HDAC4 via decoying of miR‐140‐5p. Finally, we proved that MALAT1 promoted OS tumor growth in an in vivo animal study. In summary, the outcomes of this study demonstrated the complex ceRNA network among MALAT, miR‐140‐5p, and HDAC4‐mediated proliferation and apoptosis in OS. This study might provide a new axial in molecular treatment of OS.