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》

hsa_circ_0072387 Suppresses Proliferation, Metastasis, and Glycolysis of Oral Squamous Cell Carcinoma Cells by Downregulating miR-503-5p.

Han L ，Cheng J ，Li A 《-》

Circular hsa_circ_0020377 regulates KLF7 by targeting miR-194-5p to facilitate tumor cell malignant behaviors and glycolysis in oral squamous cell carcinoma progression.

Oral squamous cell carcinoma (OSCC) is a common malignant tumor with high recurrence, metastasis rates, and poor prognosis. Numerous studies discover that circular RNA (circRNA) is closely associated with OSCC progression. Hsa_circ_0020377 has been aberrantly expressed in OSCC, but its role in tumor growth and metastasis remains largely unclear. Hsa_circ_0020377, microRNA-194-5p (miR-194-5p), and Krüppel-like factor 7 (KLF7) contents were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferative, cycle progression migration, and invasion were measured using 5-ethynyl-2'-deoxyuridine (EdU), Cell Counting Kit-8 (CCK-8), flow cytometry, wound healing, and Transwell assays. The glycolysis level was detected via specific kits. Cyclin D1, E-cadherin, hexokinase 2 (HK2), and KLF7 protein levels were detected via western blot. Using predicting bioinformatics software, the binding between miR-194-5p and hsa_circ_0020377 or KLF7 was verified using a dual-luciferase reporter and RNA Immunoprecipitation (RIP). Beyond that, a xenograft tumor model was used to analyze the role of hsa_circ_0020377 on tumor cell growth in vivo. Increased hsa_circ_0020377 and KLF7 and reduced miR-194-5p were found in OSCC tissues and cell lines. Loss-of-function experiments proved that hsa_circ_0020377 depletion might block OSCC cell proliferation, cycle progression, migration, invasion, and glycolysis in vitro. In xenograft mouse models, hsa_circ_0020377 silencing might suppress tumor growth. In addition, mechanism research suggested that hsa_circ_0020377 could bind with miR-194-5p and enhance its target gene (KLF7), thereby affecting OSCC development. These results broaden our insights regarding the regulation of OSCC progression via circRNA and act as a reference for future clinical studies in OSCC diagnosis and treatment.

Hei N ，Liu P ，Jin L ，Peng S ，Bao Y ... -  《-》

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 《-》

circ_0004872 inhibits proliferation, invasion, and glycolysis of oral squamous cell carcinoma by sponged miR-424-5p.

Oral squamous cell carcinoma (OSCC) is one of the most common oral malignant tumors. circ_0004872 can inhibit the progression of gastric cancer, but its effect on the growth and metastasis of OSCC is still unclear. qRT-PCR was used to detect the expression levels of circ_0004872 and miR-424-5p in cancer tissues of OSCC patients and adjacent normal tissues, OSCC cell lines, and human normal oral keratinocytes (HOK). CCK-8, cell colony formation, flow cytometry, and transwell assay were used to detect cell proliferation rate, viability, apoptosis rate, and invasion ability. Use glucose/lactic acid kit to assay cell glycolysis ability. The dual-luciferase reporter gene experiment and RIP experiment verified the relationship between circ_0004872 and miR-424-5p. The protein levels were examined by Western blot. The expression of circ_0004872 was significantly downregulated in OSCC tissues and cells, and the overexpression of circ_0004872 inhibited the proliferation, vitality, invasion, and glycolysis of OSCC cells, and promoted apoptosis. The expression of miR-424-5p was greatly upregulated in OSCC tissues and OSCC cells. circ_0004872 can adsorb miR-424-5p in OSCC cells, and circ_0004872 can reverse the promoting effect of miR-424-5p overexpression on the process of OSCC cells. circ_0004872 suppresses the proliferation, invasion, and glycolysis of OSCC cells by sponged miR-424-5p, and promotes apoptosis, which can be used as a potential target for early diagnosis and targeted therapy of OSCC.

Dai Y ，Zhu Y ，Xu H 《-》