MicroRNA-186 serves as a tumor suppressor in oral squamous cell carcinoma by negatively regulating the protein tyrosine phosphatase SHP2 expression.

MicroRNAs (miRs) have been shown to play critical roles in the pathogenesis of oral squamous cell carcinoma (OSCC), the current study is designed to identify the potential role of miR-186 in OSCC. Realtime polymerase chain reaction was used to determine miR-186 expression in paired tissue samples (OSCC and adjacent normal tissues) and multiple oral cell lines (normal oral keratinocyte HOK cell and OSCC cell lines). Cell viability, colony formation and flow cytometry assays were used to assess the biological function of miR-186. Furthermore, luciferase and western blot assays were used to verify the predicted target of miR-186. We found that miR-186 expression was significantly downregulated in OSCC tissues and cell lines. Overexpression of miR-186 produced an anti-growth effect and induced apoptosis in Tca8113 and SCC-25 cells. Luciferase assay revealed that miR-186 directly targeted PTPN11 (a gene encodes the protein tyrosine phosphatase SHP2) mRNA 3' untranslated region and suppressed its expression. Consistently, MiR-186 and SHP2 were negatively correlated in OSCC tissues. Consequently, miR-186 inhibited signaling activities of Extracellular Regulated protein Kinases (ERK) and Protein kinase B (AKT), which act downstream of SHP2 and are critical for growth of cancer cells. We identify that miR-186 serves as a tumor suppressor in OSCC. Downregulation of this microRNA may lead to a higher expression of oncogenic factor SHP2, which leads to activation of growth promoting signaling. Thus, miR-186 may be a novel and effective therapeutic agent for the treatment of OSCC.

Cai Z ，Hao XY ，Liu FX 《-》

Deregulation of hsa_circ_0001971/miR-186 and hsa_circ_0001874/miR-296 signaling pathways promotes the proliferation of oral squamous carcinoma cells by synergistically activating SHP2/PLK1 signals.

It has been demonstrated that circ_0001874 and circ_0001971 are potential biomarkers for the diagnosis of oral squamous carcinoma (OSCC). MiR-186 was reported to serve as a tumor suppressor in OSCC, and the down-regulation of miR-186 was reported to lead to higher expression of oncogenic factor SHP2 and the activation of growth promoting signaling. In this study, we aimed to explore the possible molecular role of circ_0001874 and circ_0001971 signaling in the pathogenesis of OSCC. RT-qPCR, Western blot, online bioinformatics tools and luciferase assay were utilized to study the molecular signaling pathways of circ_0001874 and circ_0001971. MTT assay and FCM assay were performed to investigate the synergistic effect of circ_0001971 and circ_0001874 on cell proliferation and apoptosis. By observing the effect of different miRNAs on the levels of circ_0001847 and circ_0001971, it was identified that circ_0001847 and circ_0001971 respectively sponged the expression of miR-296 and miR-186 via binding to these miRNAs. Also, SHP2 mRNA and PLK1 mRNA were respectively targeted by miR-186 and miR-296-5p. We also established two signaling pathways, i.e., circ_0001971/miR-186/SHP2 and circ_0001874/miR-296-5p/PLK1, and validated the synergistic effect of circ_0001971 and circ_0001874 via observing their positive effect on cell proliferation and negative effect on cell apoptosis. The expression of miR-186 and miR-296-5p was generally lower in saliva of OSCC patients compared with that in OLK patients, while the expression of miR-186 and miR-296-5p was specifically up-regulated in saliva of OSCC patients. In conclusion, the finding of this study demonstrated that the relative level of hsa_circ_0001971 and hsa_circ_0001874 were different in the saliva of OSCC patients and could be used as predictive biomarkers for the development of OSCC. Furthermore, oncogenic effects of hsa_circ_0001971 and hsa_circ_0001874 in the development of OSCC might be, at least partially, mediated by its downstream signaling pathways including hsa_circ_0001971/microRNA-186/SHP2 and hsa_circ_0001874/microRNA-297/PLK1.

Jun W ，Shaobo O ，Xianhua Z ，Siyu Z ，Mingyang C ，Xin F ，Ying C ，Lan L ... -  《Scientific Reports》

LncRNA UCA1 promotes proliferation and cisplatin resistance of oral squamous cell carcinoma by sunppressing miR-184 expression.

Chemotherapy resistance has become the main obstacle for the effective treatment of human cancers. Long non-coding RNA urothelial cancer associated 1 (UCA1) is generally regarded as an oncogene in some cancers. However, the function and molecular mechanism of UCA1 implicated in cisplatin (CDDP) chemoresistance of oral squamous cell carcinoma (OSCC) is still not fully established. UCA1 expression in tumor tissues and cells was tested by qRT-PCR. MTT, flow cytometry and caspase-3 activity analysis were explored to evaluate the CDDP sensitivity in OSCC cells. Western blot analysis was used to measure BCL2, Bax and SF1 protein expression. Luciferase reporter assay was conducted to investigate the molecular relationship between UCA1, miR-184, and SF1. Nude mice model was used to confirm the functional role of UCA1 in CDDP resistance in vivo. UCA1 expression was upregulated in OSCC tissues, cell lines, and CDDP resistant OSCC cells. Function analysis revealed that UCA1 facilitated proliferation, enhanced CDDP chemoresistance, and suppressed apoptosis in OSCC cells. Mechanisms investigation indicated that UCA1 could interact with miR-184 to repress its expression. Rescue experiments suggested that downregulation of miR-184 partly reversed the tumor suppression effect and CDDP chemosensitivity of UCA1 knockdown in CDDP-resistant OSCC cells. Moreover, UCA1 could perform as a miR-184 sponge to modulate SF1 expression. The OSCC nude mice model experiments demonstrated that depletion of UCA1 further boosted CDDP-mediated repression effect on tumor growth. UCA1 accelerated proliferation, increased CDDP chemoresistance and restrained apoptosis partly through modulating SF1 via sponging miR-184 in OSCC cells, suggesting that targeting UCA1 may be a potential therapeutic strategy for OSCC patients.

Fang Z ，Zhao J ，Xie W ，Sun Q ，Wang H ，Qiao B ... -  《Cancer Medicine》

miR-654-5p Targets GRAP to Promote Proliferation, Metastasis, and Chemoresistance of Oral Squamous Cell Carcinoma Through Ras/MAPK Signaling.

Lu M ，Wang C ，Chen W ，Mao C ，Wang J ... -  《-》

MicroRNA-155-5p is associated with oral squamous cell carcinoma metastasis and poor prognosis.

Abnormal miRNA expression was recently implicated in the metastasis of oral squamous cell carcinoma (OSCC) and with a poor prognosis. The initiation of the invasion-metastasis cascade involves epithelial-mesenchymal transition (EMT). Our aim was to clarify how miRNA, especially miR-155-5p misexpression contributes to OSCC metastasis through EMT. We collected tumor samples from 73 subjects with OSCC. The samples were analyzed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and correlations between miR-155-5p levels and clinical characteristics were investigated. OSCC cell lines were analyzed by miRNA microarray and by transfection with a miR-155-5p mimic or inhibitor, followed by proliferation and wound-healing migration assays. qRT-PCR analyses of EMT makers in cells transfected with miR-155-5p inhibitor were performed. We found high miR-155-5p expression in tissue samples from subjects with OSCC that had metastasized to cervical lymph nodes. HSC-3 cells also strongly expressed miR-155-5p. The epithelial marker E-cadherin was strongly expressed in HSC-3 cells transfected with miR-155-5p inhibitor, and we observed elevated SOCS1 and decreased STAT3 expression in these cells. Our results suggest that miR-155-5p causes OSCC to metastasize, and could serve as a novel therapeutic target for OSCC.

Baba O ，Hasegawa S ，Nagai H ，Uchida F ，Yamatoji M ，Kanno NI ，Yamagata K ，Sakai S ，Yanagawa T ，Bukawa H ... -  《-》