LncRNA HOTTIP promotes papillary thyroid carcinoma cell proliferation, invasion and migration by regulating miR-637

Knockdown of HOXA transcript at the distal tip suppresses the growth and invasion and induces apoptosis of oral tongue squamous carcinoma cells

Background

Oral tongue squamous cell carcinoma (OTSCC) is an aggressive cancer which has high mortality rates. HOXA transcript at the distal tip (HOTTIP) is a lncRNA that can be used as a prognostic marker in multiple carcinomas. The expression of HOTTIP is found to be elevated in OTSCC tissues, and such elevation is correlated with poor prognosis. However, its functional role in regulating the growth and metastasis of OTSCC cells remains elusive and requires further investigation.

Methods

HOTTIP-silenced OTSCC cells were established by inhibiting HOTTIP expression via its exclusive shRNA. Whether HOTTIP knockdown affected the aggressive tumor behaviors of OTSCC cells was investigated in vitro and in vivo.

Results

We found that HOTTIP shRNA restrained the cell proliferation and arrested the cell cycle at G1 phase in TSCCA and TCA8113 cells. The expression levels of cyclins B, D1, and E were downregulated in HOTTIP-silenced cells. HOTTIP silencing suppressed the growth of xenograft tumors. Moreover, the silencing of HOTTIP triggered apoptosis in TSCCA and TCA8113 cells and altered the expression of a group of apoptosis-related molecules: downregulated Bcl-2, upregulated Bax, and enhanced the cleavage of caspase 3 and PARP. Knockdown of HOTTIP also suppressed the migration, invasion, and epithelial-mesenchymal transition (EMT) of both TSCCA and TCA8113 cell lines.

Conclusion

Our findings suggest that HOTTIP is required by the OTSCC cells to maintain their growth and metastasis in vitro. It may serve as a promising potential candidate for OTSCC therapy.

Interaction of long-chain non-coding RNAs and important signaling pathways on human cancers (Review)

Long non-coding RNAs (lncRNAs) usually refer to non-coding RNA transcripts >200 nucleotides in length. In terms of the full genomic transcript, the proportion of lncRNAs far exceeds that of coding RNA. Initially, lncRNAs were considered to be the transcriptional noise of genes, but it has since been demonstrated that lncRNAs serve an important role in the regulation of cellular activities through interaction with DNA, RNA and protein. Numerous studies have demonstrated that various intricate signaling pathways are closely related to lncRNAs. Here, we focus on a large number of studies regarding the interaction of lncRNAs with important signaling pathways. It is comprehensively illustrated that lncRNAs regulate key metabolic components and regulatory factors of signaling pathways to affect the biological activities of tumor cells. Evidence suggests that the abnormal expression or mutation of lncRNAs in human tumor cells, and their interaction with signaling pathways, may provide a basis and potential target for the diagnosis and treatment of human cancers.

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 XIST promotes proliferation and invasion by targeting miR-141 in papillary thyroid carcinoma

Background

The long noncoding RNA X-inactive specific transcript (XIST) was reported to play vital roles in tumor progression. In the present study, we determined the regulatory function of XIST in papillary thyroid carcinoma (PTC).

Materials and methods

XIST expression was determined in PTC tissues and cell lines by quantitative real-time polymerase chain reaction (PCR) (qRT-PCR). Cellular proliferation, migration, and invasion were measured using the Cell Counting Kit-8 (CCK-8) assay, wound-healing assay, and transwell invasion assay, respectively. Western blotting was used to determine protein expression. The downstream target miRNAs for XIST were identified by luciferase reporter assay and qRT-PCR.

Results

Relative expression of XIST was upregulated in PTC tissues and cell lines. High XIST expression was positively correlated with TNM stage and lymph node metastasis. Function assay demonstrated that knockdown of XIST significantly decreased cell proliferation, migration, and invasion in PTC cells. Moreover, we showed that the effects of XIST on PTC cell progression were mediated by miR-141.

Conclusion

Our results demonstrated that XIST functioned as an oncogene in PTC progression by regulating miR-141, suggesting that XIST might be a promising therapeutic target for PTC treatment.

Long non-coding RNA HOTTIP is upregulated in renal cell carcinoma and regulates cell growth and apoptosis by epigenetically silencing of LATS2

Renal cell carcinoma (RCC) is one of the most aggressive malignancies with increasing incidence worldwide and is characterized by dismal prognosis owing to a lack of early detection and prognostic biomarkers for this fatal disease. Accumulating studies demonstrated that abnormally expressed long non-coding RNAs (lncRNAs) are involved in tumorigenesis and progression. Specifically, HOTTIP is upregulated and exerts oncogenic properties in some cancers. However, its clinical significance, biological functions and molecular mechanisms in RCC have not been studied. In the current study, RT-qPCR was performed to quantify the relative expression of HOTTIP in RCC tissues and cells. Additionally, we explored its clinical value using Fisher's exact test. Moreover, cell growth and apoptosis altered by HOTTIP was evaluated in vitro and in vivo. Mechanistically, RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) analysis was used to determine its molecular mechanism in cell growth and apoptosis. As a result, upregulated HOTTIP is closely associated with unfavorable phenotypes in RCC patients. The mechanistic investigations showed that HOTTIP could bind to enhancer of zeste homolog 2 (EZH2) and lysine specific demethylase 1 (LSD1), thereby repressing LATS2 expression. Collectively, our study illustrates how HOTTIP plays an oncogenic role in RCC and may offer a potential therapeutic target for treating this fatal disease.