oxalylglycine and 3-(5--hydroxymethyl-2--furyl)-1-benzylindazole

The study was established to inquire into the protective effect of the HIF-1α (Hypoxia-inducible factor-1α)/ BNIP3(Bcl-2/adenovirus E1B 19-kDa interacting protein) signal path-induced-autophagy during myocardial ischemia/ reperfusion (I/R) and oxygen-glucose deprivation/recovery (OGD/R) injury in heart-derived H9C2 cells as well as its potential underlying mechanism.. Immediate myocardial I/R in SD (Spraque Dawley) rats and cytotoxicity of OGD/R injury on H9C2 cells with and without inhibitors or agonists of HIF-1α and BNIP3 were evaluated. Expression of mitochondrial autophagic protein were detected by Western blot and immunofluorescence. And the mitochondrial autophagosome were detected using Transmission Electron Microscope (TEM).. I/R and OGD/R injury increased the expression level of HIF-1α, activated the downstream BNIP3 and subsequently triggered mitochondria-dependent autophagy. Up-regulation the expression of HIF-1α and BNIP3 may promote the cardiac myocytes of SD rats of I/R injure and OGD/R injury-induced autophagy of H9C2 cells. Moreover, down-regulation the expression of HIF-1α or BNIP3-siRNA decreased H9C2 cells autophagy under OGD/R injury.. Together, our studies indicated that HIF-1α synchronization regulate BNIP3 during OGD/R injury-induced autophagy in H9C2 cells, though BNIP3-induced autophagy acting as a survival mechanism.

Topics: Amino Acids, Dicarboxylic; Animals; Apoptosis; Autophagy; Beclin-1; Cell Hypoxia; Cell Line; Hypoxia-Inducible Factor 1, alpha Subunit; Indazoles; Male; Membrane Proteins; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Proteins; Models, Animal; Myocardial Reperfusion Injury; Myocytes, Cardiac; Rats; Rats, Sprague-Dawley; Signal Transduction

Hypoxia-inducible factor (HIF)-1 plays a key role in tumor promotion by inducing approximately 60 genes required for tumor adaptation to hypoxia; thus, it is viewed as a target for cancer therapy. For this reason, YC-1, which down-regulates HIF-1alpha and HIF-2alpha at the post-translational level, is being developed as a novel anticancer drug. We here found that YC-1 acts in a novel manner to inhibit HIF-1. In the Gal4 reporter system, which is not degraded by YC-1, YC-1 was found to significantly inactivate the COOH-terminal transactivation domain (CAD) of HIF-1alpha, whereas it failed to inactivate CAD(N803A) mutant. In coimmunoprecipitation assays, YC-1 stimulated factor inhibiting HIF (FIH) binding to CAD even in hypoxia, whereas it failed to increase the cellular levels of hydroxylated Asn803 of CAD. It was also found that YC-1 prevented p300 recruitment by CAD in mammalian two-hybrid and coimmunoprecipitation assays. The involvement of FIH in YC-1-induced CAD inactivation was confirmed in EPO-enhancer and Gal4 reporter systems using FIH small interfering RNA and dimethyloxalylglycine FIH inhibitor. Indeed, FIH inhibition rescued HIF target gene expressions repressed by YC-1. In cancer cell lines other than Hep3B, YC-1 inhibits HIF-1alpha via the FIH-dependent CAD inactivation as well as via the protein down-regulation. Given these results, we suggest that the functional inactivation of HIF-alpha contributes to the YC-1-induced deregulation of hypoxia-induced genes.

Topics: Amino Acids, Dicarboxylic; Cell Line, Tumor; Enzyme Activators; Gene Expression Regulation, Neoplastic; Genes, Reporter; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Indazoles; Mixed Function Oxygenases; Models, Biological; p300-CBP Transcription Factors; Plasmids; Protein Biosynthesis; Repressor Proteins; RNA, Small Interfering; Transcriptional Activation