TM7SF4对人甲状腺乳头状癌细胞IHH-4增殖、凋亡和侵袭的作用研究

Effects of TM7SF4 on proliferation, apoptosis and invasion of human papillary thyroid cancer IHH-4 cells

目的 探讨树突表达特异性7跨膜蛋白（TM7SF4）的低表达对人甲状腺乳头状癌细胞IHH-4增殖、凋亡和侵袭的作用及其相关机制.方法 选取甲状腺乳头状癌患者的手术标本（癌组织及癌旁组织）及甲状腺乳头状癌细胞系IHH-4为对象.qRT-PCR法检测病理组织和细胞系IHH-4中TM7SF4的mRNA表达量.分别用MTT法、流式细胞分析和Transwell法检测TM7SF4表达量对IHH-4细胞增殖、凋亡和侵袭的影响.Western印迹检测IHH-4细胞中磷酸化与非磷酸化磷脂酰肌醇3激酶（PI3K）、蛋白激酶B（Akt）、哺乳动物雷帕酶素靶蛋白（mTOR）的表达.结果 与癌旁组织相比,甲状腺癌组织中TM7SF4的mRNA表达水平显著升高（t=52.31,P＜0.05）.与正常甲状腺细胞系Nthy-ori 3-1相比,IHH-4细胞系中TM7SF4的表达水平也显著上升（t=34.35,P＜0.05）.与对照组细胞相比,沉默TM7SF4的表达后,可诱导IHH-4细胞凋亡,而细胞增殖和侵袭能力受到显著抑制（F=8.32,7.55,846.40;P均＜0.05）.此外,沉默TM7SF4的表达后可显著降低磷酸化PI3K、磷酸化Akt、磷酸化mTORmRNA及蛋白的表达（F=1014.88,1121.29,985.22,720.14,854.63,4 563.12;P均＜0.05）.结论 低表达的TM7SF4可能通过下调PI3K/Akt/mTOR通路而抑制IHH-4细胞增殖、诱导凋亡并抑制侵袭.

Objective To investigate the effects and mechanisms of dendrocyte expressed seven transmembrane protein （TM7SF4） on proliferation,apoptosis and invasion of human papillary thyroid cancer （PTC） cell IHH-4.Methods PTC tumor tissues and the adjacent normal tissues,as well as the human PTC IHH-4 cells were used in this study.TM7SF4 mRNA in tissues and in IHH-4 cells were analyzed using qRT-PCR analysis.The effects of TM7SF4 on proliferation,apoptosis and invasion of IHH-4 cells were analyzed using MTI assay,flow cytometry and Transwell assay,respectively.Furthermore,Western blottingwas used to detect the expression of TM7SF4,phosphorylated and non-phosphorylated phosphatidylinositol 3-kinase （PI3K）,protein kinase B （Akt）,mammalian target of rapamycin （mTOR） protein.Results Compared with adjacent normal tissues,TM7SF4 mRNA and protein were significantly increased IHH-4 in PTC tissues （t =52.31,P 〈0.05）.TM7SF4 was also significantly increased in cells compared with that in Nthy-ori 3-1 cells （t =34.35,P 〈 0.05）.Consequently,silencing TM7SF4 significantly induced IHH-4 cells apoptosis,inhibited proliferation and suppressed invasion compared with controls （F=8.32,7.55,846.40;all P 〈0.05）.Moreover,the mRNA and protein levels of phosphorylated-PI3K,phosphorylatedAkt and phosphorylated-mTOR were significantly decreased by silencing TM7SF4 （F =1 014.88,1 121.29,985.22,720.14,854.63,4 563.12,all P 〈 0.05）.Conclusion Down-regulated TM7SF4 may be an inhibitor of PTC development and metastasis through suppressing PI3K/Akt/mTOR pathway.