Translationally controlled tumor protein (TCTP) is a novel anti apoptotic protein which is highly expressed in several cancer cell types including prostate cancer. However, studies investigating the role of TCTP in prostate cancer are scarce. Therefore, in this study we evaluated the effect of small interference RNA (siRNA) based knocking down of TCTP gene in prostate cancer cells. Cell proliferation and apoptosis were evaluated. Our results showed that TCTP is highly expressed in LNCaP cells compared to normal prostate epithelial cells. Transfection with TCTP siRNA specifically and drastically reduced the expression of both mRNA and protein levels of TCTP in LNCaP cells. The decreased expression of TCTP was associated with decreased viability of LNCaP cells. Further analysis of the transfected LNCaP cells showed that they undergo apoptosis via caspase-8 and caspase-3 dependent pathways. Results presented herein suggest a potential therapeutic application for prostate cancer by targeting TCTP gene using an siRNA approach.

Abstract. The present study reports the identification of human sex hormone binding globulin (SHBG)-interacting proteins in the brain using a phage display-based screening technology. Phage display is a system in which a foreign protein is displayed on the surface of a bacteriophage as a fusion protein with one of the coat proteins of the bacteriophage. T7 phage clones expressing normal human brain proteins (human normal brain phage-display cDNA expression library) were screened using SHBG as bait. The bound phage clones were then identified by DNA sequencing and by BLAST search analysis. Of the twenty binding proteins analyzed, three were found to be membrane-associated proteins: synaptosomal associated protein 25 (SNAP25), Thy-1 cell surface antigen and zonadhesin. Further studies will determine if the interactions of SHBG with these proteins have any role in the internalization and cell signaling events or whether they contribute to steroid delivery to specific cells.