RESUMEN
OBJECTIVE: Mitofusin-2 (MFN2) is a mitochondrial membrane protein that plays a critical role in regulating mitochondrial fusion and cellular metabolism. To further elucidate the impact of MFN2, this study aimed to investigate its significance on hepatocellular carcinoma (HCC) cell function and its potential role in mediating chemosensitivity. METHODS: This study investigated the effects of silencing and overexpressing MFN2 on the survival, proliferation, invasion and migration abilities, and sorafenib resistance of MHCC97-L HCC cells. Additional experiments were conducted using XAV939 (a ß-catenin inhibitor) and HLY78 (a ß-catenin activator) to further validate these findings. RESULTS: Silencing MFN2 significantly promoted the survival and proliferation of MHCC97-L cells, enhanced their invasion and migration capacities, increased the IC50 of sorafenib, reduced the percentage of TUNEL-positive cells, and decreased the expression of proapoptotic proteins. Additionally, silencing MFN2 markedly induced the nuclear translocation of ß-catenin, increased ß-catenin acetylation levels and enhanced the expression of the downstream regulatory proteins Snail1 and Vimentin while inhibiting E-cadherin expression. Conversely, overexpressing MFN2 reversed the effects observed in MHCC97-L cells mentioned above. The results confirmed that silencing MFN2 activated the ß-catenin/epithelial-mesenchymal transition (EMT) pathway and reduced the sensitivity of cells to sorafenib, which could be reversed by XAV939 treatment. Conversely, overexpression of MFN2 inhibited the ß-catenin/EMT pathway and increased the sensitivity of cells to sorafenib, which could be altered by HLY78. CONCLUSION: Low expression of MFN2 in HCC cells promotes the nuclear translocation of ß-catenin, thereby activating the EMT pathway and mediating resistance to sorafenib.
Asunto(s)
Carcinoma Hepatocelular , Movimiento Celular , Proliferación Celular , Resistencia a Antineoplásicos , GTP Fosfohidrolasas , Neoplasias Hepáticas , Sorafenib , Vía de Señalización Wnt , beta Catenina , Humanos , Sorafenib/farmacología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Línea Celular Tumoral , beta Catenina/metabolismo , beta Catenina/genética , Vía de Señalización Wnt/efectos de los fármacos , Vía de Señalización Wnt/genética , Proliferación Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Movimiento Celular/genética , Resistencia a Antineoplásicos/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Silenciador del Gen , Antineoplásicos/farmacología , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Transición Epitelial-Mesenquimal/efectos de los fármacos , Transición Epitelial-Mesenquimal/genética , Apoptosis/efectos de los fármacos , Apoptosis/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacosRESUMEN
Abnormal gene transcription plays an important role in oncogenesis. In cancer cells, the improper activation of specific genes is usually ascribed to aberrant transcription machinery including transcription factors, RNA polymerase II, and Mediator complex. This study reports on short hairpin RNA (shRNA)-mediated gene silencing of MED19, a subunit of Mediator complex, and its effect on the growth of pancreatic cancer cells. RNA interference was performed by lentivirus shRNA system to specifically knockdown MED19 expression in Aspc-1 and Panc-1 cells. The knockdown efficiency of MED19 was confirmed by quantitative RT-PCR and western blot. The effect of MED19 shRNA on Aspc-1 and Panc-1 cell proliferation was evaluated by methylthiazoletetrazolium assay, BrdU incorporation assay, colony formation assay, and flow cytometry assay. This study shows that downregulation of MED19 remarkably reduced cancer cell proliferation and colony formation capacity in two pancreatic cancer cell lines. In addition, downregulated MED19 induced G1-phase cell cycle arrest and apoptosis. This study provides a potent role of MED19 in promoting pancreatic cancer growth and a possible drug target for cancer therapy.