四元复合体介导C-MYC反义RNA抑制肝癌细胞生长增殖

Suppression of tumorigenicity by C-MYC antisense RNA gene with a four-element complex

目的探讨四元复合体介导的C-MYC反义RNA转移系统对肝癌细胞系HepG2.2.15致瘤性的体内外抑制作用。方法C-MYC反义RNA四元复合体体外瞬时转染HepG2.2.15细胞,流式细胞术检测C-MYC蛋白的表达水平、细胞凋亡率及细胞周期的变化,MTT法测定细胞增殖代谢活性。以HepG2.2.15细胞制备荷瘤裸鼠模型,局部瘤内注射C-MYC反义RNA四元复合体或联合注射IFN-α,称量瘤重,免疫组化方法检测肿瘤组织C-MYC蛋白的表达。结果C-MYC反义RNA可显著降低细胞C-MYC蛋白的表达水平,使细胞生长停滞于G0/G1期。体内抑瘤实验显示,反义治疗组瘤体C-MYC蛋白表达降低,瘤重(1.72±0.16)g,显著低于生理盐水对照组(P<0.05)。联合IFN-α注射组抑瘤效果更佳。结论肿瘤组织靶向性C-MYC反义RNA转移系统在体内外均可有效降低C-MYC蛋白的表达,抑制细胞的生长增殖。体内联合IFN-α可取得更佳的抑瘤效果。

Objective To study the inhibitory effects of C-MYC antisense RNA mediated by a four-element complex on tumorigenicity of hepatocellular carcinoma cell line HepG2.2.15 both in vitro and in vivo. Methods The four-element complex ,containing C-MYC antisense RNA, was constructed and transiently transfected into HepG2.2.15 cells.72 h later, cells were collected and assayed for the expression of C-MYC protein, cell cycle distribution and apoptosis rate by flow cytometry. BALB/c nude mice bearing with HepG2.2.15 cells were injected with four-element complex including pcDNA-AS-MYC or IFN-α concomitantly . After being sacrificed, the weight of tumor were measured and the expression of C-MYC protein of tumor tissues was detected by immunohistochemistry. Results After transfection by C-MYC antisense RNA four-element complex, the expression of C-MYCprotein of HepG2.2.15 cells was greatly diminished;cell cycle was trapped at G_0/G_1 phase; apoptosis rate was not significantly affected. MTT assay indicated that after transfection with C-MYC antisense RNA, the potential growth activity and metabolism of HepG2.2.15 cells were effectively inhibited. When HepG2.2.15 cells were implanted into nude mice, injection of C-MYC antisense RNA four-element complex could significantly inhibited the expression of C-MYC protein in tumor tissue and the weight of tumor[(1.720.16)g,P<0.05].When injected by C-MYC antisense RNA and IFN-αconcurrently, the tumor was smaller than C-MYC antisense RNA alone. Conclusion C-MYC antisense RNA mediated by a four-element complex effectively inhibited the expression of C-MYC protein and impaired the tumorigenicity of HepG2.2.15 cells both in vitro and in vivo. When injected together with IFN-α,the inhibitory effect was more significant.