与再生肝细胞共培养对结肠癌细胞增生反应的影响

目的 探讨与再生肝细胞共培养时结肠癌细胞增生潜能的改变及其可能机制.方法 人结肠痛细胞株SW480,与70%肝切除大鼠模型术后24 h采用原位胶原酶灌流法分离获得有活性的再生肝细胞以不同比例混合进行体外培养;采用3H].胸腺嘧啶核苷(3H-TdR)掺入率和Westernblot检测细胞培养24、72、96和120 h的增生反应及表皮生长因子受体(EGFR)、胰岛素样生长因子-1受体(IGF-1R)和肝细胞生长因子受体(c-met)表达变化.结果 1:1和1:10比例共培养组结肠癌细胞增生反应增强,3H-TdR掺人率从培养第72 h开始增加,至第120 h呈持续增加趋势(P<0.05),EGFR和IGF-1R从第24 h开始表达增强,且表达水平呈时间效应关系,c-met表达无明显变化;10:1比例共培养组结肠癌细胞增生情况、3种受体表达水平均无明显变化.结论 与再生肝细胞共培养可增强结肠癌细胞EGFR、IGF-1R的表达,方式可能来自于肝细胞内的生长信号通过旁分泌机制增强结肠癌细胞EGFR和IGF-1R的表达,从而促进结肠癌细胞的增生反应.

Hyperproliferation of human colon cancer cells in co-cultures of rat regenerating hepatocytes

Objective To investigate the stimulated proliferation of colon cancer cells in co-cultures of regenerating hepatocytes. Methods Regenerating hepatocytes(24 hours after partial hepatectomy)were obtained by collagenase perfusion of models of rats undergoing 70% liver resection. To determine whether the ratio of human colon cell line SW480 cells to hepatocytes in co-cultures has influence on their interaction,these cells were cultured in ratios of 1: 101:1, or 10: 1. Proliferation capacity was assessed by the percentage of 3 H-TdR incorporation. Expression of epidermal growth factor receptor(EGFR), insulin-like growth factor1 receptor(IGF-1R)and hepatocyte growth factor receptor(c-met) were analyzed by western blot. Results For co-cultured SW480 and hepatocytes in the ratios of 1: 1 and 1: 10, an increase of disintegrations per minute(dpm) occurred after 72 hours' culture, and lasted at 120 hours' culture(P < 0.05). No difference was found between the group with ratio of 10:1 and control group. Protein levels of EGFR and IGF-1R, but not c-met, were significantly increased between culture of 24 hours and 120 hours; however, no change of these receptors was found in the ratio of 10: 1. Conclusions These results imply that co-culturing human colon cancer cells with regenerating hepatocytes leads to increased expression of EGFR and IGF-1R. We conclude that this effect is probably dependent on paracrine stimulation, by which numerous signals from the hepatocytes contribute to the hyperproliferative state of colon cancer cells via up-regulating the responding receptors.