Division of Gastroenterology and Liver Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
Hepatology. 2013 Nov;58(5):1667-80. doi: 10.1002/hep.26526. Epub 2013 Sep 19.
Radiofrequency ablation (RFA) is a potentially curative therapy for hepatocellular carcinoma (HCC). However, incomplete RFA can induce accelerated invasive growth at the periphery. The mechanisms underlying the RFA-induced tumor promotion remain largely unexplored. Three human HCC cell lines were exposed to 45°C-55°C for 10 minutes, simulating the marginal zone of RFA treatment. At 5-12 days post-treatment cell proliferation, parameters of epithelial-mesenchymal transition (EMT), and activation of mitogen-activated protein kinases were analyzed. Livers from patients with viral hepatitis without and with HCC (n = 114) were examined to confirm the relevance of altered kinase patterns. In vivo tumorigenic potential of heat-treated versus untreated HCC cells was studied in nude mice. Heating to 55°C killed all HCC cells, whereas 65%-85% of cells survived 48°C-50°C, developing spindle-like morphology and expressing CD133, cytokeratin (CK)7, CK19, procollagen-α1(I), and Snail at day 5 after heat exposure, which returned to baseline at day 12. Heat-exposed HCC cells showed enhanced proliferation and prominent activation of p46-Shc (Src homology and collagen) and downstream extracellular signal-related kinase (Erk)1/2. In patients, Shc expression correlated with malignant potential and overall survival. Blocking Erk1/2 reduced proliferation and EMT-like changes of heat-treated HCC cells. Implantation of heat-exposed HEPG2 cells into nude mice induced significantly larger, more aggressive tumors than untreated cells.
Sublethal heat treatment skews HCC cells toward EMT and transforms them to a progenitor-like, highly proliferative cellular phenotype in vitro and in vivo, which is driven significantly by p46Shc-Erk1/2. Suboptimal RFA accelerates HCC growth and spread by transiently inducing an EMT-like, more aggressive cellular phenotype.
射频消融（RFA）是治疗肝细胞癌（HCC）的一种潜在的根治性疗法。然而，不完全的 RFA 会导致边缘区域的肿瘤加速侵袭性生长。RFA 诱导肿瘤促进的机制在很大程度上仍未得到探索。将三种人 HCC 细胞系暴露于 45°C-55°C 10 分钟，模拟 RFA 治疗的边缘区域。在治疗后 5-12 天，分析细胞增殖、上皮-间充质转化（EMT）的参数以及丝裂原活化蛋白激酶的激活情况。检查了患有病毒性肝炎且无 HCC（n=114）和有 HCC 的患者的肝脏，以确认改变的激酶模式的相关性。在裸鼠中研究了经热处理与未经处理的 HCC 细胞的体内致瘤潜力。加热至 55°C 可杀死所有 HCC 细胞，而 48°C-50°C 下 65%-85%的细胞存活，在热暴露后第 5 天出现纺锤形形态，并表达 CD133、细胞角蛋白（CK）7、CK19、前胶原-α1（I）和 Snail，在第 12 天恢复基线。热暴露的 HCC 细胞表现出增强的增殖和显著的 p46-Shc（Src 同源和胶原）和下游细胞外信号相关激酶（Erk）1/2 的激活。在患者中，Shc 表达与恶性潜能和总生存相关。阻断 Erk1/2 减少了热处理的 HCC 细胞的增殖和 EMT 样变化。将热暴露的 HEPG2 细胞植入裸鼠中会导致明显更大、更具侵袭性的肿瘤，而未处理的细胞则不会。
亚致死热处理使 HCC 细胞向 EMT 倾斜，并在体外和体内将其转化为祖细胞样、高增殖的细胞表型，这主要由 p46Shc-Erk1/2 驱动。次优的 RFA 通过短暂诱导 EMT 样、侵袭性更强的细胞表型来加速 HCC 的生长和扩散。
