Role of Six Trans Membrane Protein of Prostate (STAMP) Proteins in Prostate Cancer- Relation with Survival Genes

Abstract

Prostate cancer studies focus on identification of androgen receptor (AR) regulated genes that are also highly expressed in the prostate. As a promising candidate, STAMP family genes STAMP1/STEAP2, STAMP2/STEAP4 and STEAP3 are involved in apoptosis and the cell cycle in metastatic prostate cancer. Vascular NADPH oxidase generates superoxide and other ROS, which stimulates IkappaB degradation and NF-kB activation by subunits of NADPH oxidases, namely p47phox and p67phox induced by different stimuli such as hydrogen peroxide. Hydrogen peroxide increased the expression levels of p67phox. They also have a role in redox-sensitive genes such as STAMP gene family. Flow cytometry analysis of LNCaP cells was performed using Annexin V staining and apoptotic index charts were drawn. STAMP1 and STAMP2 showed total anti-oxidant capacity versus control with hydrogen peroxide incubation. Using siRNA technology in LNCaP cells expressing mutant p53 silencing of p53 showed significant increase in MDM2 and decrease of caspase 9 mRNA levels at RT-PCR. Silencing of STAMP2, a significant decrease in p47phox was shown but STAMP1 silencing counteracted this effect on Cu/ZnSOD expression.As a conclusion, STAMP proteins have effects on oxidative stress-induced genes with significant and opposite changes.