Purpose: The combination of prostate specific antigen (PSA) and human glandular kallikrein (KLK2) promoters and/or enhancers was used to establish a new model to determine the feasibility of tissue specific expression for prostate cancer.
Materials and methods: In vitro studies used the construction of PSA and KLK2 promoters/enhancers vectors to elucidate the link between the promoter/enhancer of PSA and KLK2. Reverse transcriptase-polymerase chain reaction assays were used to determine cell specific expression. Therefore, an attractive tissue specific expression vector for PSA and KLK2 gene was identified.
Results: The reporter vectors driven by KLK2 promoter had much lower luciferase activities than those of the reporter vectors driven by PSA promoter in LNCaP cells. Furthermore, the most efficient and cell specific reporter activity after 5alpha-androstan-17beta-ol-3-one treatment among the reporter vectors constructed in this study was that of pKLK2EPSABHE, which was driven by KLK2 enhancer and PSA promoter/enhancer. The pKLK2EPSABHE reporter vector could induce 800-fold higher than the KLK2 basic promoter and its reporter activity was 16 times that of the enhancer/promoter element of KLK2 following induction by androgen.
Conclusions: The results verify that the PSA promoter/enhancer must be combined with KLK2 to ensure the full activity and cell specificity of the gene. These expressions coupled with mechanic target validation yield valuable clues regarding the model of action of complex mixtures. This model is a potentially useful tool in gene therapy for metastatic prostate cancer.