Department of Gastroenterology, The First Hospital of Jilin University, Changchun, Jilin Province, China.
Neoplasma. 2011;58(3):239-44. doi: 10.4149/neo_2011_03_239.
In hepatocellular carcinoma (HCC), Wnt/β-catenin, Ras/MAPK and PI3K/AKT signaling pathways form a complex network and play important roles during HCC genesis and development. To study their relationship and the influence on cell growth, the siRNA directed against β-catenin was transfected into HCC HepG2 cells. β-catenin mRNA and protein levels were measured respectively at various times by RT-PCR and Western blot. Furthermore, HCC cell growth was measured by MTT assay. Finally, MAPK family and Akt1 protein levels were also measured by Western blot. After the transfection, β-catenin mRNA levels were markedly inhibited at 24 h and increased gradually at 48, 72 and 96 h; β-catenin protein levels decreased gradually at 24, 48 and 72 h and slightly increased at 96 h. HCC cell growth was inhibited from 24-72 h, but this inhibition decreased at 96 h. ERK1/2 (p42/p44 MAPK), JNK/SAPK, p38 MAPK, and Akt1 protein levels showed no change following transfection, while their phosphorylated protein levels showed changes. Thus, siRNA directed against β-catenin markedly decreased β-catenin gene expression and inhibited cell growth. Wnt/β-catenin signaling pathway might regulate Ras/MAPK and PI3K/Akt signaling pathways through regulation of the phosphorylation state of ERK1/2, JNK/SAPK and Akt1 protein in HCC HepG2 cells. These pathways might compensate for the inhibitory effect of β-catenin, thereby affecting tumor cell growth and others downstream factors.
在肝细胞癌（HCC）中，Wnt/β-catenin、Ras/MAPK 和 PI3K/AKT 信号通路形成一个复杂的网络，在 HCC 的发生和发展过程中发挥着重要作用。为了研究它们之间的关系及其对细胞生长的影响，用针对β-catenin 的 siRNA 转染 HCC HepG2 细胞。分别在不同时间用 RT-PCR 和 Western blot 法检测β-catenin mRNA 和蛋白水平。另外，用 MTT 法检测 HCC 细胞生长情况。最后，用 Western blot 法检测 MAPK 家族和 Akt1 蛋白水平。转染后，β-catenin mRNA 水平在 24 h 时明显受到抑制，在 48、72 和 96 h 时逐渐升高；β-catenin 蛋白水平在 24、48 和 72 h 时逐渐下降，在 96 h 时略有升高。HCC 细胞生长在 24-72 h 时受到抑制，但在 96 h 时抑制作用减弱。ERK1/2（p42/p44 MAPK）、JNK/SAPK、p38 MAPK 和 Akt1 蛋白水平转染后无变化，但其磷酸化蛋白水平发生变化。因此，针对β-catenin 的 siRNA 可显著降低β-catenin 基因表达并抑制细胞生长。Wnt/β-catenin 信号通路可能通过调节 HCC HepG2 细胞中 ERK1/2、JNK/SAPK 和 Akt1 蛋白的磷酸化状态来调节 Ras/MAPK 和 PI3K/Akt 信号通路。这些通路可能会补偿β-catenin 的抑制作用，从而影响肿瘤细胞生长和其他下游因子。
