LncRNA CASC9 Promotes Proliferation and Inhibits Apoptosis of Oral Squamous Cell Carcinoma Cells by Regulating miR-423-5p/NRSN2 Axis
LI Liheng1 *, WANG Rui1, WANG Qin1, ZHANG Zhiyi1, AN Feng1, ZHANG Xuan1, WANG Xiaoming1, ZHANG Fan2
OSCC (oral squamous cell carcinoma) is a highly invasive malignant tumor of the head and neck, which seriously threatens human health. The purpose of the study was to investigate the effects of LncRNA CASC9 (long chain non coding RNA tumor susceptible candidate 9) regulating the miR-423-5 p/NRSN2 (neurensin-2) axis on the proliferation and apoptosis of OSCC cells. qRT-PCR (quantitative real-time PCR) was used to detect the expression level of CASC9 in cancer tissues of 21 OSCC patient and hSC-3, CAL-27, SCC-15 cell; divide SCC-15 cells into control group, sh-NC-1 group, sh-CASC9 group, miR-NC group, miR-423-5p mimics group, anti-miR-NC group, anti-miR-423-5p group, sh-NC group, sh-NRSN2 group, sh-CASC9+anti-miR-NC group and sh-CASC9+anti-miR-423-5p group, qRT-PCR was used to detect the expression of CASC9 and miR-423-5p, cell proliferation, apoptosis and the expression of NRSN2 protein were detected by CCK-8, flow cytometry and Western blot, respectively; the effect of CASC9 on tumor growth was observed by tumor xenograft experiment in nude mice; RNA pull down and the dual luciferase reporter gene experiment were used to detect the targeting relations hip of CASC9 and miR-423-5p, miR-423-5p and NRSN2. The results show that, CASC9 was highly expressed in OSCC tissues and cells, and the expression of CASC9 was the highest in SCC-15 cells, therefore, SCC-15 cells were used as the research object; silencing CASC9 could inhibit the proliferation of SCC-15, promote apoptosis and inhibit tumor formation in nude mice (P<0.05); CASC9 targeted and negatively regulated the expression of miR-423-5p, and miR-423-5p targeted and negatively regulated the expression of NRSN2; inhibition of miR-423-5p could promote the proliferation and inhibit apoptosis of SCC-15 cells, and down-regulation of NRSN2 could inhibit the proliferation and promote apoptosis of SCC-15 cells; inhibition of miR-423-5p expression weakened the effect of silencing CASC9 on OSCC cells (P<0.05). In short, silencing of CASC9 inhibits the proliferation and promotes apoptosis of SCC-15 cells by targeting up-regulation of miR-423-5p to inhibit the expression of NRSN2.
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