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Human osteocalcin: a strong promoter for nitric oxide synthase gene therapy, with specificity for hormone refractory prostate cancer
Author(s) -
McCarthy Helen O.,
Coulter Jonathan A.,
Worthington Jenny,
Robson Tracy,
Hirst David G.
Publication year - 2007
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.1045
Subject(s) - du145 , lncap , transfection , cancer research , prostate cancer , biology , microbiology and biotechnology , nitric oxide synthase , endocrinology , medicine , cell culture , chemistry , cancer , nitric oxide , genetics
Background Gene therapy has been identified as a promising treatment strategy for hormone refractory prostate cancer (HRPC). We report, for the first time, the use of the human osteocalcin (hOC) promoter to control inducible nitric oxide synthase (iNOS) transgene expression in HRPC. Methods Human prostate carcinoma cells (PC3, DU145, LNCaP), colon cancer cells (HT29) and human microvascular endothelial cells (HMEC‐1) were transfected in vitro with constitutively driven CMV/iNOS or hOC/iNOS plasmid DNA by cationic lipid vector. End points of these experiments were Western blotting, NO · generation using the Greiss test to measure accumulated nitrite, and clonogenic assay. Results Transfection of the hOC/iNOS plasmid increased iNOS protein and total nitrite levels in PC3 and DU145 cells, but not LNCaP or HT29. Transfection with CMV/iNOS or hOC/iNOS resulted in no additional cytotoxicity in androgen‐dependent LNCaP cells or in the non‐prostate cell lines. However, transfection with either construct resulted in a greatly reduced cell survival (to 10–20%) in the androgen‐independent PC3 and DU145 cell lines. Conclusions Utilising the tumour‐type specific properties of the hOC promoter in tandem with the iNOS gene, we have demonstrated target cell specificity, and transgene activation, in the androgen‐independent prostate cancer cell lines (PC3 and DU145), an effect absent in normal and androgen‐dependent cells. Furthermore, the levels of NO · generated are comparable with those seen generated with constitutively (CMV)‐driven iNOS. The data obtained from this study provide a basis for future development of hOC/iNOS gene therapy. Copyright © 2007 John Wiley & Sons, Ltd.