Procaine has anti-proliferative effect and functions as an inhibitor of DNA methylation in human hepatocellular carcinoma and gastric cancer

本研究揭示了局麻药普鲁卡因（PCA）对人肝癌细胞（HLE、HuH7、HepG2、Hep3B、PLC/PRF/5、HuH6）和胃癌细胞（AGS、MKN1、MKN45、MKN74、KATOIII）具有体外生长抑制和去甲基化作用。MTS法检测加或不加trichostatin A （TSA）的PCA处理细胞的活力，发现PCA处理后HLE、HuH7、HuH6及所有胃癌细胞的活力均显著降低。在这些细胞中，TSA和PCA联合处理表现出更强的活力降低。为了阐明PCA抗增殖作用的机制，我们对PCA处理的细胞进行TUNEL实验、FACS分析和形态学观察。经pca处理的HLE细胞S/G2/M转变受到抑制，细胞出现空泡化等形态学改变，凋亡率未见增加。肝癌细胞或胃癌细胞中被DNA高甲基化转录抑制的基因在PCA治疗后被证明是去甲基化和重新激活的。在移植异种肿瘤的裸鼠身上测试了PCA在体内的生长抑制作用，发现PCA治疗可以显著减少体内肿瘤体积。综上所述，这些数据表明，PCA在体外和体内对人肝癌细胞和胃癌细胞具有生长抑制和去甲基化作用。PCA可能是未来治疗肝癌和胃癌的候选药物。

In this study, we revealed that a local anesthetic, procaine (PCA), possessed growth-inhibitory and demethylating effect on human hepatoma cells (HLE, HuH7, HepG2, Hep3B, PLC/PRF/5, HuH6) and gastric cancer cells (AGS, MKN1, MKN45, MKN74, KATOIII) in vitro. The viability of PCA-treated cells with or without trichostatin A (TSA) was assessed by MTS assay and found that the viability of HLE, HuH7, HuH6 and all gastric cancer cells examined was significantly decreased by PCA treatment. In these cells, the combination treatment with TSA and PCA exhibited stronger reduction of the viability. To clarify the mechanism of the anti-proliferating effect of PCA, TUNEL assay, FACS analysis and morphological observation of PCA-treated cells were performed. Inhibition of S/G2/M transition, morphological changes such as vacuolation and no increase in apoptosis rate were observed in the PCA-treated HLE cells. The genes that were transcriptionally suppressed by DNA hypermethylation in hepatoma cells or gastric cancer cells were demonstrated to be demethylated and reactivated after PCA treatment. The growth-inhibitory effect of PCA in vivo was tested in nude mice bearing xenograft and PCA treatment was revealed to lead to a significant reduction in tumor volume in vivo. In conclusion, these data indicated that PCA had growth-inhibitory and demethylating effects on human hepatoma cells and gastric cancer cells in vitro and in vivo. PCA may be a candidate agent for future therapies against HCC and gastric cancer.