射频消融治疗后转化生长因子-β对肝癌干细胞发生和肝癌复发的影响

Study on the effect of transforming growth factor beta (TGF-β) on the development of cancer stem cells and the recurrence of hepatocellular carcinoma after radiofrequency ablation

目的探讨肝癌射频消融(RFA)治疗后,外周血转化生长因子(TGF-β)对肿瘤组织中肝癌干细胞(LCSCs)发生和肝癌复发的影响。方法检测肝癌RFA治疗后的患者外周血TGF-β和肿瘤组织LCSCs的水平;体外实验研究亚致死温度对肝癌细胞系Hep1-6中肿瘤干细胞和TGF-β水平的影响。结果 RFA治疗后10例患者外周血TGF-β水平显著下降(Ⅰ型患者),另10例患者TGF-β水平显著增高(Ⅱ型患者)。Ⅰ、Ⅱ型患者肝癌复发时间分别为(2.45±1.46)和(11.90±3.72)个月,差异有统计学意义(P<0.001)。RFA治疗后,I型患者复发肝癌组织中CD13 mRNA的水平较治疗前明显上调,上调2倍以上;但RFA治疗对Ⅱ型患者CD13mRNA水平无明显影响。小鼠肝癌细胞系Hep1-6用45℃亚致死温度处理10 min后再继续培养24 h。45℃处理相比37℃处理,可显著上调CD13^+Hep1-6细胞水平(P<0.001),并且45℃处理导致Sox2表达增加和TGF-β表达下降。用中和抗体抑制TGF-β可显著增加CD13^+ Hep1-6细胞水平(P<0.001);而用Sox2 siRNA抑制Sox2表达则显著减少CD13^+ Hep1-6细胞水平(P<0.001)。结论 TGF-β可以通过抑制Sox2的表达来抑制LCSCs的产生,从而抑制肝癌复发。

Objective To study the effect of transforming growth factor beta（TGF-β） in blood and liver cancer stem cells（LCSCs） in tumor tissue on tumor recurrence of hepatocellular carcinoma（HCC） after radiofrequency ablation（RFA）. Methods The levels of TGF-β in blood and LCSCs in tumor tissue of HCC patients treated by RFA were measured. The effect of sub-lethal temperature treatment on TGF-β and LCSCs in Hep1-6 cells in vitro were detected. Results RFA decreased TGF-β in 10 patients（termed type I）, but increased in the other 10 patents（termed type II）. The mean interphase of type I and II was 2.45 and 11.90 months, respectively（P〈0.001）. RFA increased CD13 expression in tumor tissue in type I（at least more than 2-folds）, but RFA had no effect on CD13 expression in type II. Hep1-6 cells, a mouse HCC cell line, were treated by 45℃ for 10 minutes and then were cultured with usual condition. 45℃ treatment resulted in upregulation of Sox2 and down-regulation of TGF-β. Blocking TGF-β with neutralizing antibody significantly enhanced the levels of CD13＋ Hep1-6 cells after 45℃ treatment（P0.001）, while knock down of Sox2 by siRNA could significantly reduce the level of CD13＋ cells（P〈0.001）. Conclusion TGF-β can inhibit Sox2 expression and then inhibit the production of CD13＋ LCSCs, which plays an inhibitory role on HCC recurrence.