Department of Liver Surgery; Liver Cancer Institute; Zhongshan Hospital; Fudan University; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education; Shanghai, China.
Autophagy. 2013 Dec;9(12):2056-68. doi: 10.4161/auto.26398. Epub 2013 Oct 1.
Metastasis is one of the main causes of poor prognosis for hepatocellular carcinoma (HCC), which has been linked to cell-death resistance. Autophagy is an important survival mechanism under conditions of cell stress. We hypothesized that autophagy may play a role in HCC metastasis due to its prosurvival effect. Highly metastatic HCC cell lines with stable autophagy inhibition were established via lentivirus-mediated silencing of BECN1 and ATG5 genes. Mouse models of pulmonary metastasis were then developed using the cells with or without autophagy inhibition. The analysis of lung metastasis by histopathological examination and small animal imaging showed that autophagy inhibition significantly decreased the incidence of pulmonary metastases in vivo. Further invasion, migration, detachment, lung colonization, and epithelial-mesenchymal transition (EMT) assays indicated that autophagy inhibition did not affect cell invasiveness, migration or EMT but attenuated the anoikis-resistance and lung colonization of HCC cells. Investigation of the molecular mechanisms underlying showed that the autophagy-inhibition-mediated anoikis-resistance attenuation was associated with the regulation of apoptotic signaling. As autophagy inhibition was shown to be able to suppress HCC metastasis, an autophagy-based HCC tissue-specific target therapy system (AFP-Cre/LoxP-shRNA) was constructed. In vitro and in vivo analyses showed that the system was able to efficiently inhibit autophagy of HCC cells and tissue in a tissue-specific manner. Further in vivo metastasis assay showed that intratumoral administration of the system could significantly suppress lung metastasis. Together, our findings suggest that autophagy may be involved in HCC metastasis through facilitating anoikis resistance and lung colonization of HCC cells. Autophagy-based HCC tissue-specific target therapy may be a new strategy for the management of HCC metastasis.
转移是肝细胞癌（HCC）预后不良的主要原因之一，这与细胞死亡抵抗有关。自噬是细胞应激条件下的一种重要生存机制。我们假设自噬可能在 HCC 转移中发挥作用，因为它具有促进生存的作用。通过慢病毒介导的 BECN1 和 ATG5 基因沉默，建立了具有稳定自噬抑制的高转移性 HCC 细胞系。然后使用具有或不具有自噬抑制的细胞在小鼠模型中建立肺转移。通过组织病理学检查和小动物成像对肺转移的分析表明，自噬抑制显著降低了体内肺转移的发生率。进一步的侵袭、迁移、脱落、肺定植和上皮-间充质转化（EMT）测定表明，自噬抑制不影响细胞侵袭性、迁移或 EMT，但减弱了 HCC 细胞的无接触凋亡抵抗和肺定植。对潜在分子机制的研究表明，自噬抑制介导的无接触凋亡抵抗减弱与凋亡信号的调节有关。由于自噬抑制被证明能够抑制 HCC 转移，因此构建了基于自噬的 HCC 组织特异性靶向治疗系统（AFP-Cre/LoxP-shRNA）。体外和体内分析表明，该系统能够以组织特异性的方式有效地抑制 HCC 细胞和组织的自噬。进一步的体内转移试验表明，该系统的肿瘤内给药能够显著抑制肺转移。总之，我们的研究结果表明，自噬可能通过促进 HCC 细胞的无接触凋亡抵抗和肺定植参与 HCC 转移。基于自噬的 HCC 组织特异性靶向治疗可能是 HCC 转移管理的一种新策略。
