ABSTRACT
It is well known that tumors damage affected tissues; however, the specific mechanism underlying such damage remains elusive. AMP-activated protein kinase (AMPK) senses energetic changes and regulates glucose metabolism. In this study, we examined the mechanisms by which AMPK promotes metabolic adaptation in the tumor-bearing liver using a murine model of colon cancer liver metastasis. Knock-out of AMPK α2 significantly enhanced tumor-induced glucose deprivation in the liver and increased the extent of liver injury and hepatocyte death. Mechanistically, we observed that AMPK α2 deficiency resulted in elevated reactive oxygen species, reduced mitophagy, and increased cell death in response to tumors or glucose deprivation in vitro. These results imply that AMPK α2 is essential for attenuation of liver injury during tumor metastasis via hepatic glucose deprivation and mitophagy-mediated inhibition of reactive oxygen species production. Therefore, AMPK α2 might represent an important therapeutic target for colon cancer metastasis-induced liver injury.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Glucose/deficiency , Liver Neoplasms/metabolism , Liver Neoplasms/secondary , Liver/injuries , Liver/metabolism , Oxidative Stress , AMP-Activated Protein Kinases/deficiency , AMP-Activated Protein Kinases/genetics , Animals , Cell Line, Tumor , Colonic Neoplasms/pathology , Energy Metabolism , Gene Knockout Techniques , Hepatocytes/cytology , Hepatocytes/metabolism , Hepatocytes/pathology , Humans , Liver/pathology , Liver Neoplasms/pathology , Mice , Mitophagy , Necrosis/metabolism , Reactive Oxygen Species/metabolismABSTRACT
Discovery of the RNA interference (RNAi) pathway has led to exciting new strategies for developing HIV treatment. This study was to find out the highly effective and conserved siRNA target sequences for improving RNAi-based therapy against the HIV-1. We constructed 30 shRNA expression plasmids for expressing different siRNAs targeted to HIV-1 vif and co-transfected them with the pNL4-3 to score for its ability to inhibit the expression of p24 protein of HIV-1. Then, the highly effective siRNAs targeting sequences were selected to align with 625 HIV-1 sequences in database including all HIV-1 subtypes to ana lyze their conserved character. In addition, vif37 the highly effective and most conserved target sequence was confirmed of its sequence-specific inhibition by independent reporter assays. MT-4 cell transduced with lentiviral shRNA-vif37 vector could inhibit HIV-1(NL4.3) replication in vitro. Moreover, MT-4-vif37 cloned from transduced MT-4 cell could stably express shRNA-vif37 and inhibit virus replication more efficiently when challenged with high titer virus. These results showed that RNAi has great potential as an antiviral gene therapy approach and supports the efforts to develop treatment for HIV-1-infected individuals.