吉非替尼和靶向表皮生长因子受体小干扰RNA治疗前列腺癌

目的 观察吉非替尼(Gefitinib)和靶向表皮生长因子受体(EGFR)小干扰RNA(siRNA)体内外抑制前列腺癌的效果并探讨其作用机制.方法 前列腺癌细胞PC-3转染慢病毒为载体的EGFR siRNA或Gefitinib(0～10 ms/L)处理后,噻唑蓝(iT)比色法检测细胞生长抑制率,荧光聚合酶链反应(PCR)检测EGFR mRNA表达,Western blot检测EGFR、丝氨酸蛋白激酶(Akt)、促分裂原活化蛋白激酶(MAPK)和蛋白激酶c(PKC)表达.体内观察EGFR siRNA和Gefitinib单独或联合抑瘤效果.结果 EGFR siRNA对PC-3细胞转染率达85%,细胞生长抑制率为40%～50%,而Gefitinib细胞生长抑制率呈浓度.时间依赖性.EGFR siRNA对PC-3细胞EGFR mRNA和蛋白表达抑制率＞90%,明显高于Gefitinib的＜80%(P＜0.01);EGFR siRNA显著抑制Akt和MAPK表达,而Gefifimb仅明显抑制Akt表达.Gefitnib单独和联合EGFR siRNA的抑瘤率分别为53.95%和59.28%,明显高于EGFR siRNA组的34.83%(P＜0.05).结论 EGFR通路抑制剂能有效抑制前列腺癌生长,其机制主要通过阻断EGFR及其胞内蛋白Akt的表达来实现.

Effects of gefitinib and small interfering RNAs targeting EGFRin the treatment of prostate eallcer

Objective To probe into the inhibitory effects and mechanisms of Cefitinib and small interfering RNAs ( siRNA) targeting epidermal growth factor receptor ( EGFR) ( EGFR siRNA) against hormone independent prostate cancer (HIPC) in vitro and in vivo. Methods After PC-3 cells were trans-fected with lentivirus mediated EGFR siRNA recombinant or treated with Gefitinib (0-10 mg/L), MTT was used to measure cell growth inhibitory rate (IR), fluorescent real-time polymerase chain reaction (PCR) to detect EGFR mRNA level, and Western blotting to assay the expression of EGFR and its intracellular proteins, such as Akt, MAPK and PKC. Tumor growth was observed when EGFR siRNA or/and Gefitinib were used to treat mice with transplanted tumors. Results The IR of PC-3 cells was 40% -50% by using EGFR siRNA and transfection efficiency was 85%. Gefitnib inhibited the growth of PC-3 cells in a time-and concentration-dependent manner. The expression of EGFR mRNA and protein in PC-3 cells was down-regulated over 90% which was obviously higher than < 80% in Gefitinib group (P < 0.01) ; EGFR siRNA could significantly inhibit the expression of Akt and MAPK, but Gefitinib only significantly inhibit the expression of Akt. In the in vivo study, the tumor growth was inhibited significantly in Gefitinib group (53.95%) or Gefitinib + EGFR siRNA group (59. 28%) as compared with EGFR siRNA group (34. 83% ,P <0. 05). Conclusion EGFR pathways inhibitors could block PC cells growth effectively mainly via the down-regulation of the expression of EGFR and its intracellular protein Akt.