The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China.
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China.
Oncol Rep. 2019 Jan;41(1):154-164. doi: 10.3892/or.2018.6788. Epub 2018 Oct 12.
Transmembrane protein 40 (TMEM40) is a 23‑kDa protein and its association with tongue squamous cell carcinoma (TSCC) remains unclear. This study aimed to investigate the expression and clinical significance of TMEM40 in TSCC and its roles in TSCC cells. Immunohistochemical analysis was performed to detect the expression levels of TMEM40 in 60 tongue tissue samples. Furthermore, TMEM40 was overexpressed and inhibited in two TSCC cell lines by transfection with pEZ‑M98‑TMEM40 plasmid or TMEM40 small interfering RNA, respectively. Cell Counting Kit‑8 and colony formation assays were used to investigate the effects of TMEM40 on cell proliferation and colony formation ability, respectively. Flow cytometry was performed to determine cell apoptosis and cycle conditions of transfected cells. Wound‑healing and Transwell assays were processed to explore the effects of TMEM40 on cell migration and invasion, respectively. The results indicated that TMEM40 expression levels were significantly increased in TSCC tissues compared with adjacent normal tongue tissues (P<0.01). Clinicopathological analysis revealed that TMEM40 expression was positively correlated with pathological TNM (pTNM) status (P<0.05), histological grade (P<0.001) and clinical stage (P<0.01), but not with sex or age. Results of cell proliferation, apoptosis, migration and invasion assays indicated that when TMEM40 had been successfully overexpressed or knocked down in CAL27 and SCC9 TSCC cell lines, cell growth and invasion increased in the TMEM40 overexpressing cells, while they decreased in TMEM40‑knockdown cells. Furthermore, experiments revealed that TMEM40 knockdown resulted in increased levels of p53 and Bax, and decreased levels of MMP‑9, which indicated that TMEM40 regulated cell apoptosis and migration via involvement of p53, Bax and MMP‑9 in TSCC cells. Our findings indicated that increased expression of TMEM40 contributed to progressive features of TSCC via regulation of p53, Bax and MMP‑9.
跨膜蛋白 40（TMEM40）是一种 23kDa 蛋白，其与舌鳞状细胞癌（TSCC）的关系尚不清楚。本研究旨在探讨 TMEM40 在 TSCC 中的表达及临床意义及其在 TSCC 细胞中的作用。采用免疫组织化学分析检测 60 例舌组织标本中 TMEM40 的表达水平。此外，通过转染 pEZ-M98-TMEM40 质粒或 TMEM40 小干扰 RNA 分别在两种 TSCC 细胞系中过表达和抑制 TMEM40。细胞计数试剂盒-8 和集落形成实验分别用于研究 TMEM40 对细胞增殖和集落形成能力的影响。流式细胞术用于确定转染细胞的细胞凋亡和周期状态。划痕愈合和 Transwell 实验分别用于研究 TMEM40 对细胞迁移和侵袭的影响。结果表明，与相邻正常舌组织相比，TMEM40 在 TSCC 组织中的表达水平显著升高（P<0.01）。临床病理分析表明，TMEM40 的表达与病理 TNM（pTNM）分期（P<0.05）、组织学分级（P<0.001）和临床分期（P<0.01）呈正相关，而与性别或年龄无关。细胞增殖、凋亡、迁移和侵袭实验结果表明，在 CAL27 和 SCC9 TSCC 细胞系中成功过表达或敲低 TMEM40 后，TMEM40 过表达细胞的细胞生长和侵袭增加，而 TMEM40 敲低细胞的细胞生长和侵袭减少。此外，实验表明 TMEM40 敲低导致 p53 和 Bax 水平升高，MMP-9 水平降低，表明 TMEM40 通过参与 TSCC 细胞中的 p53、Bax 和 MMP-9 调节细胞凋亡和迁移。我们的研究结果表明，TMEM40 的表达增加通过调节 p53、Bax 和 MMP-9 促进了 TSCC 的进展特征。
