核糖体蛋白L22(RPL22)通过MDM2-p53信号通路抑制SW620细胞增殖

RPL22 inhibits the proliferation of SW620 cell line via MDM2-p53 signal pathway

目的:研究核糖体蛋白L22(ribosomal protein L22,RPL22)在人结肠癌细胞SW620内抑制细胞增殖的机制。方法:通过5-氟尿嘧啶(5-fluorouracil,5-FU)和放线菌素(actinomycin D,Act D)选择性的触发SW620细胞内的核糖体压力反应,再利用RNAi技术沉默RPL22,检测在RPL22沉默状态下细胞核糖体压力反应触发的效应率;使用流式细胞技术分析RPL22蛋白对SW620细胞周期的影响;最后通过BLI技术检测RPL22蛋白与p53的调节蛋白MDM2的相互作用情况,确定其靶向抑制MDM2进而激活p53的分子机制。结果:与未敲出RPL22基因的细胞比较,5-FU及Act D无法有效启动核糖体压力反应并激活L22沉默的SW620细胞内的p53;流式细胞检测同时发现敲出RPL22基因的细胞在核糖体压力反应下仍然大部分停留在G_1/G_0期,而原始状态下的细胞经5-FU及Act D处理后则更易于向分裂期过渡;BLI技术发现RPL22与MDM2有较强的相互作用,但与p53及p21等蛋白结合较弱。结论:RPL22基因对核糖体压力引起的细胞增殖抑制有着重要的影响,其机制可能是通过抑制MDM2从而激活p53信号通路实现的。

Objective：To probe the mechanism of ribosomal protein（RPL22）on cell proliferation inhibition to SW620 cell line.Methods：SW620 cell line was treated by 5-fluorouracil（5-FU）or actinomycin D（Act D）to launch the ribosomal stress,then,RNAi technology was plunged into this section in order to check out the function of RPL22 on cell ribosomal stress.Flow cytometry was introduced to confirm the function of RPL22 on cell cycle regulation.Last,to illustrate the molecular mechanism of RPL22 on p53 signal pathway.We also analyzed the interaction between RPL22 and MDM2,or RPL22 and p53 by BLI technology.Results：Compared with the control group,5-FU or Act D was unable to trigger the ribosomal stress and active p53 signal pathway,due to lack of RPL22 gene.Besides,RPL22 seemed to take a responsibility for the transition of cell cycle from G0/G1to S/G2.5-FU or Act D could not block the transition process that from G0/G1to S/G2while SW620 cell line was out of RPL22 gene.Another assay about proteins interaction in vitro showed that RPL22 protein had relatively high affinity to MDM2,but weak affinity to p53.Conclusion：RPL22 gene is able to inhibit the proliferation of SW620 cell line which in the status of ribosomal stress,and the potential mechanism is associated with inhibition of MDM2/p53 signal pathway.