Anti-cancer agent piperlongumine is an inhibitor of transient receptor potential melastatin 7 channel in oral squamous cell carcinoma.

OBJECTIVES: To elucidate the association between the anticancer activities of piperlongumine (PL) and its potential target, transient receptor potential melastatin 7 channel (TRPM7), in oral squamous cell carcinoma (OSCC). METHODS: The expression levels and electrical characteristics of TRPM7 as well as cell viability in response to various PL treatments were investigated in the OSCC cell line Cal27. RESULTS: PL treatment resulted in a concentration- and time-dependent reduction in TRPM7 mRNA and protein expression in Cal27 cells. Furthermore, PL treatment inhibited TRPM7-like rectifying currents in Cal27 cells; however, this inhibition was less effective than that of the TRPM7 antagonist waixenicin A. Rapid perfusion and washout experiments revealed an immediate inhibitory effect of PL on TRPM7-like currents. The antagonistic effect of PL occurred within 1 min and was not completely reversed following washout. Notably, the extracellular Ca2+ concentration still influenced PL-induced changes in the TRPM7-like current, indicating that PL can directly but gently antagonize the TRPM7 channel. Functional changes in TRPM7 correlated with the observed antiproliferative and cytotoxic effects of PL in Cal27 cells. CONCLUSIONS: These findings suggest that PL exhibits potent inhibitory effects on TRPM7 and exerts its anti-cancer effects by downregulating TRPM7 expression and antagonizing channel currents.

Long non-coding RNA XIST promotes the malignant features of oral squamous cell carcinoma (OSCC) cells through regulating miR-133a-5p/VEGFB.

OBJECTIVE: Oral squamous cell carcinoma (OSCC) represents a frequently seen oral cavity malignancy, and the mechanisms of its occurrence and development remain unclear. The present work examined the expression and biological function of long non-coding RNA (lncNRA) XIST (X-inactive specific transcript) in OSCC cells and tissues. STUDY DESIGN: A total number of 50 OSCC and paired non-carcinoma tissue samples were collected in this study. Gene expression levels in cancer tissues and cells were quantified by RT-qPCR. In addition, gain- and loss-of-function experiments were conducted to investigate the biological roles of XIST as well as its downstream targets in OSCC cells. RESULTS: XIST was upregulated in OSCC cells and tissues, which predicted a poorer prognostic outcome in OSCC patients. Silencing XIST inhibited the growth and invasion of OSCC cells and triggered apoptosis. miR-133a-5p was identified as a downstream target of XIST, which was downregulated in OSCC tissues. miR-133a-5p mediated the effect of XIST by targeting VEGFB. VEGFB overexpression rescued the inhibitory effects of XIST silencing on cell growth, invasion and migration. CONCLUSION: Taken together, the above data indicates that XIST serves as an oncogenic factor to enhance the growth and invasion of OSCC cells by targeting the miR-133a/VEGFB axis.

Effect of MicroRNA-138 on Tumor Necrosis Factor-Alpha-Induced Suppression of Osteogenic Differentiation of Dental Pulp Stem Cells and Underlying Mechanism.

High doses of tumor necrosis factor-α (TNF-α) suppress osteogenic differentiation of human dental pulp stem cells (hDPSCs). In the present study, we aimed to explore the role and potential regulatory mechanism of microRNA-138 (miR-138) in the osteogenic differentiation of hDPSCs after treatment with a high dose of TNF-α. The hDPSCs were cultured in osteogenic medium with or without 50 ng/ml TNF-α. The miR-138 levels were upregulated during osteogenic differentiation of the hDPSCs following TNF-α treatment. The miR-138 overexpression accelerated but miR-138 knockdown alleviated the TNF-α-induced suppression of the alkaline phosphatase activity, calcium deposition, and protein abundance of dentin sialophosphoprotein, dentin matrix protein 1, bone sialoprotein, and osteopontin during osteogenic differentiation induction of hDPSCs. Additionally, miR-138 overexpression accelerated but miR-138 knockdown alleviated the suppression of the focal adhesion kinase- (FAK-) extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway during osteogenic differentiation induction of hDPSCs under TNF-α treatment. In conclusion, miR-138 accelerates TNF-α-induced suppression of osteogenic differentiation of hDPSCs. Inactivation of the FAK-ERK1/2 signaling pathway may be one of the mechanisms underlying the effect of miR-138. Inhibition of miR-138 expression may be a strategy to weaken the inhibitory effect of high-dose TNF-α on the osteogenic differentiation of hDPSCs.

LINC00460 facilitated tongue squamous cell carcinoma progression via the miR-320b/IGF2BP3 axis.

OBJECTIVE: We aimed to explore the role of long intergenic non-protein coding RNA 460 (LINC00460) in tongue squamous cell carcinoma (TSCC). METHODS: We enrolled 27 TSCC patients to explore LINC00460 expression in clinical TSCC samples. RT-qPCR measured expression of molecules in this research. Loss-of-function assays explored biological function of LINC00460 in TSCC cells. RNA pull-down assay, luciferase reporter assay, and RIP assay investigated mechanism of LINC00460 underlying TSCC cells. RESULTS: TSCC tissues and cell lines both showed high expression of LINC00460. Functionally, LINC00460 downregulation inhibited TSCC cell growth and promoted TSCC cell apoptosis. Additionally, LINC00460 silencing suppressed tumor growth in vivo. Mechanistically, LINC00460 bound with microRNA 320b (miR-320b) in TSCC cells. MiR-320b overexpression suppressed TSCC cell growth and promoted TSCC cell apoptosis. Moreover miR-320b targeted insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) 3'untranslated region in TSCC cells. Furthermore, IGF2BP3 silencing suppressed TSCC cell growth and promoted TSCC cell apoptosis. IGF2BP3 upregulation countervailed effects of silenced LINC00460 on TSCC cells. The LINC00460/miR-320b/IGF2BP3 axis was associated with lymph node metastasis of TSCC patients. CONCLUSION: Our research illustrated that LINC00460 facilitated TSCC progression via the miR-320b/IGF2BP3 axis, highlighting a potential insight for the treatment of TSCC.

circVAPA promotes the proliferation, migration and invasion of oral cancer cells through the miR-132/HOXA7 axis.

OBJECTIVE: To study the relationship between the circular RNA vesicle-associated membrane protein-associated protein A (circVAPA) and the pathogenesis of oral squamous cell carcinoma. METHODS: The expression of circVAPA was detected by RT-qPCR. In vitro loss-of-function experiments were performed in Cal-27 cells. The malignant phenotype of cells was evaluated by cell counting kit-8, clone formation and transwell assays. Luciferase reporter assays were used to assess the circVAPA/miR-132/homeobox A (HOXA) regulatory axis. RESULTS: circVAPA expression was significantly increased in oral cancer tissues and cells. The overall survival and progression-free survival of patients with oral cancer who exhibited high circVAPA expression were significantly shorter compared with those with low expression. circVAPA expression was closely related to tumor size, TNM stage and distant metastasis. circVAPA knockdown reduced the proliferation, invasion and migration of Cal-27 cells. MiR-132 was identified as a target of circVAPA in Cal-27 cells. Cotransfection with si-circVAPA and miR-132 inhibitor reversed the inhibitory effect of circVAPA knockdown on cell malignant phenotypes. HOXA7 was further identified as a downstream target of miR-132. CONCLUSION: circVAPA is highly expressed in oral cancer, and its abnormal expression might affect the proliferation, invasion and migration of oral cancer cells by modulating the miR-132/HOXA7 signaling axis.