miR-143-3p靶向KRAS阻滞PI3K/Akt信号通路抑制分化型甲状腺癌细胞增殖、侵袭和迁移

目的:探讨miR-143-3p对分化型甲状腺癌细胞增殖、侵袭和迁移的影响及其作用机制。方法:采用qRT-PCR检测miR-143-3p在30例分化型甲状腺癌组织和对应的癌旁组织，以及人分化型甲状腺癌细胞（TCP-1、FTC-133、SW579、BCPAP）和甲状腺滤泡上皮正常细胞（Nthy-ori3-1）中的表达水平。将miR-143-3p mimic和miR-143-3p mimic+pcDNA3.1-KRAS转染于FTC-133细胞中，采用CCK-8检测FTC-133细胞增殖活力；Transwell检测FTC-133细胞侵袭和迁移能力。双荧光素酶报告基因验证miR-143-3p和KRAS的靶向关系。Western blot检测蛋白的表达水平。结果:miR-143-3p在分化型甲状腺癌组织中的表达水平明显低于对应的癌旁组织。miR-143-3p在分化型甲状腺癌细胞系中的表达水平低于甲状腺滤泡上皮正常细胞的表达，尤其在FTC-133细胞中表达最低。过表达miR-143-3p显著抑制了FTC-133细胞增殖、侵袭和迁移能力。此外，双荧光素酶报告基因证实，KRAS为miR-143-3p的靶基因。进一步，过表达KRAS通过激活PI3K/Akt信号通路缓解了仅过表达miR-143-3p对FTC-133细胞增殖、侵袭和迁移能力的抑制作用。结论:过表达miR-143-3p通过靶向KRAS且阻滞PI3K/Akt信号通路，进而抑制分化型甲状腺癌细胞恶性生物学行为。

miR-143-3p targeted KRAS to block PI3K/Akt signaling pathway and inhibit proliferation,invasion and migration of differentiated thyroid carcinoma cells

Objective:To explore the effect of miR-143-3p on proliferation,invasion and migration of differentiated thyroid carcinoma cells and its underlying mechanism.Methods:qRT-PCR was employed to examine the expression of miR-143-3p in 30 cases of differentiated thyroid carcinoma tissues and matched adjacent tissues,and differentiated thyroid carcinoma cell lines(TCP-1,FTC-133,SW579,BCPAP)and human thyroid follicular epithelial normal cells(Nthy-ori3-1).The miR-143-3p mimic and miR-143-3p mimic+pcDNA3.1-KRAS were respectively transfected into FTC-133 cells.After transfection,cell proliferation,invasion,and migration in FTC-133 cells were monitored by CCK-8 and Transwell assay,respectively.The relationship between miR-143-3p and KRAS was verified by dual-luciferase reporter gene.The levels of protein were detected by Western blot.Results:The expression of miR-143-3p was down-regulated in differentiated thyroid carcinoma tissues compared with the paired adjacent normal tissues.In parallel,the expression of miR-143-3p in differentiated thyroid carcinoma cell lines was lower than that in the human thyroid follicular epithelial normal cells,especially the lowest expression in FTC-133 cells.Compared with the control group,miR-143-3p elevated significantly decreased FTC-133 cell proliferation,invasion,and migration abilities.Besides,we identified KRAS as a direct target of miR-143-3p by dual-luciferase reporter gene.Furthermore,up-regulated expression of KRAS reversed the inhibitory effect of miR-143-3p overexpression on FTC-133 cell proliferation,invasion,and migration through activation the PI3K/Akt signaling pathway.Conclusion:Upregulation of miR-143-3p inactivated the PI3K/Akt signaling pathway to suppress cell malignant biological behavior via targeting KRAS in differentiated thyroid carcinoma.