KLF4沉默与阿霉素诱导的DNA损伤协同抑制肝癌HepG2细胞的生长

探究KLF4沉默与经不同作用浓度阿霉素处理诱导的DNA损伤对肝癌HepG2细胞增殖凋亡的影响及其作用机制.应用RNA干扰技术，采用siRNA转染HepG2细胞以沉默KLF4基因.采用MTT法检测KLF4沉默前后对HepG2细胞增殖的影响，使用流式细胞术检测KLF4沉默前后对HepG2细胞周期变化影响，应用Western blot法检测转染前后HepG2细胞中KLF4蛋白及细胞周期相关蛋白表达变化.Western blot检测到高浓度的阿霉素促进KLF4的表达，并且低浓度的阿霉素可使得细胞停滞在G2/M期，高浓度的阿霉素则使部分细胞凋亡(19.31%).将KLF4沉默后，发现细胞生长变缓，低浓度的阿霉素处理后，细胞随时间增加而出现更多的细胞凋亡；高浓度的阿霉素处理后，细胞数明显减少，更多的细胞发生凋亡(28.89%)，且在KLF4沉默前后均发现低浓度阿霉素促进p53与p21表达，高浓度阿霉素抑制其表达.阿霉素诱导的DNA损伤可提高KLF4的表达，KLF4依赖于DNA损伤激活的p53促进p21的表达，进而引起G1/S期细胞周期阻滞.沉默KLF4与阿霉素诱导的DNA损伤可协同抑制肝癌细胞的增殖、促进凋亡，其在肝癌细胞 HepG2中扮演十分重要的角色.

KLF4 silencing and doxorubicin-induced DNA damage inhibit the growth of hepatocellular carcinoma HepG2 cells

In this paper， the effect of KLF4 silencing and DNA damage induced by different concentrations of doxorubicin on proliferation and apoptosis of HepG2 cells and its related mechanism were investigated. RNA interference technique was applied to siRNA transfection of HepG2 cells to silence KLF4 genes. And the effect of KLF4 on HepG2 cell proliferation treated with cytostatic concentration and cytotoxic concentration on doxorubicin were detected by MTT assay before and after KLF4 knockdown. The effect of KLF4 on HepG2 cell cycle was analyzed by flow cytometry before and after KLF4 silence. The expression of KLF4 protein and cell cycle related protein in HepG2 cells was examined by western blot before and after transfection. Western blot results showed that high concentration of doxorubicin promoted the expression of KLF4. Moreover， low concentrations of doxorubicin caused cells arrest in G2/M phase， while high concentrations of doxorubicin induced cell apoptosis (19.31%). After silencing KLF4， the MTT results showed that cell growth decreased. Cells treated with low concentration of doxorubicin， exhibited more apoptosis with increasing time. After treatment with high concentration of doxorubicin， cell viability reduced significantly， and number of apoptotic cells increased (28.89%). Moreover， the expression of p53 and p21 were promoted by low concentration of doxorubicin while inhibited by high concentration of doxorubicin. Doxorubicin-mediated DNA damage enhanced the expression of KLF4. In summary， KLF4 might inhibit the proliferation and promote apoptosis of human hepatoma cancer cells through p21 signal pathway and DNA damage-activated p53 signal pathway， suggesting its important function in hepatoma cancer HepG2 cells.