RESUMO
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. The current treatment of HCC mainly includes surgery, chemotherapy, and liver transplantation. HCC differentiation therapy aims to restore tumor cells' normal liver characteristics and unlock their phenotypic plasticity. Understanding the molecular and signaling pathways that control HCC differentiation can help identify new targets for inducing differentiation and provide ideas for drug design. Downregulation of liver enriched transcription factors, imbalanced signal pathway, and dysregulated microRNA play essential roles in regulating the differentiation state of HCC. Restoring normal expression levels of these molecules could induce the tumor cells to differentiate into hepatocyte-like cells (HLCs) and suppress the malignant tumor phenotype. The strategies for inducing HLCs from induced pluripotent stem cells, fibroblasts, and other somatic cells provide a reference for the induced differentiation of liver cancer. The differentiation therapy is expected to be a promising and effective treatment for HCC.
Assuntos
Carcinoma Hepatocelular , Células-Tronco Pluripotentes Induzidas , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , Neoplasias Hepáticas/metabolismo , Diferenciação Celular/genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Adaptação Fisiológica , Linhagem Celular TumoralRESUMO
BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, hence a major public health threat. Pleomorphic adenoma gene like-2 (PLAGL2) has been reported to play a role in tumorigenesis. However, its precise function in HCC remains poorly understood. APPROACH AND RESULTS: In this study, we demonstrated that PLAGL2 was up-regulated in HCC compared with that of adjacent nontumorous tissues and also correlated with overall survival times. We further showed that PLAGL2 promoted HCC cell proliferation, migration, and invasion both in vitro and in vivo. PLAGL2 expression was positively correlated with epidermal growth factor receptor (EGFR) expression. Mechanistically, this study demonstrated that PLAGL2 functions as a transcriptional regulator of EGFR and promotes HCC cell proliferation, migration, and invasion through the EGFR-AKT pathway. Moreover, hypoxia was found to significantly induce high expression of PLAGL2, which promoted hypoxia inducible factor 1/2 alpha subunit (HIF1/2A) expression through EGFR. Therefore, this study demonstrated that a PLAGL2-EGFR-HIF1/2A signaling loop promotes HCC progression. More importantly, PLAGL2 expression reduced hepatoma cells' response to the anti-EGFR drug erlotinib. PLAGL2 knockdown enhanced the response to erlotinib. CONCLUSIONS: This study reveals the pivotal role of PLAGL2 in HCC cell proliferation, metastasis, and erlotinib insensitivity. This suggests that PLAGL2 can be a potential therapeutic target of HCC.