ABSTRACT
Our objectives were to determine whether heme oxygenase-1 is a second messenger for prolactin-mediated angiogenesis. Endothelial cell proliferation and angiogenesis assay demonstrated that cell number and capillary formation were increased by prolactin (10 and 25 ng/ml). Both protein synthesis and mRNA analysis confirmed that HO-1 expression was induced by prolactin in cultured endothelial cells and occurred in a concentration-dependent manner. Endothelial cells transduced with retrovirus-mediated delivery of HO-1 gene in sense and antisense orientation were used to further determine whether HO-1 overexpression or underexpression modulated prolactin-mediated endothelial cell proliferation and angiogenesis. Incubation of human microvessel endothelial cells transduced with HO-1 in sense orientation resulted in enhancement of prolactin-mediated increase in endothelial cell proliferation and angiogenesis, whereas inhibition of HO-1 by transduction of HO-1 in antisense orientation prevented prolactin increase in endothelial cell proliferation. Similarly, addition of stannic mesoporphyrin, the inhibitor of HO activity, prevented PRL-mediated increase in endothelial cell proliferation. Our results demonstrated for the first time, that prolactin-mediated angiogenesis and cell proliferation was dependent on HO-1 gene expression.
Subject(s)
Cell Division/physiology , Endothelium, Vascular/metabolism , Heme Oxygenase (Decyclizing)/metabolism , Neovascularization, Pathologic/enzymology , Prolactin/pharmacology , Endothelium, Vascular/drug effects , Genetic Vectors , Heme Oxygenase (Decyclizing)/biosynthesis , Heme Oxygenase (Decyclizing)/genetics , Humans , In Vitro Techniques , RetroviridaeABSTRACT
Pyrrolidindithiocarbamate (PDTC), is a metal chelator widely used to study the activation of redox sensitive transcription factors. Recently it has been demonstrated that it manifests pro-oxidant properties. The nuclear factor-Kappa B (NF-kappaB) transcription factor can both promote cell survival and induce apoptosis depending on cell type and context in response to genotoxic stress. In our previous study we reported that in acute myelogenous leukemia CD34+ cells PDTC stimulates apoptosis, whereas in CD34+ cells of healthy volunteers PDTC was ineffective. This cytotoxicity was dependent on the generation of superoxide anion and oxidized glutathione. In this article we have shown that the pro-oxidant effect of PDTC in AML cells induces NF-kappaB activity. These findings imply a role for NF-kappaB in the survival of normal cells with respect to leukemic cells, suggesting that NF-kappaB activity and function differs according to tumor cell phenotype.