Prostate-tumor targeting of gene expression by lentiviral vectors containing elements of the probasin promoter.
BACKGROUND
Lentiviruses are retroviruses that can infect and stably integrate into the chromatin of non-dividing cells. The purpose of this study was to determine whether lentiviral vectors containing the probasin (PB) promoter displayed prostate-specific, androgen-regulated, and persistent gene expression.


METHODS
Three lentiviral-PB promoter/enhanced green fluorescent protein (EGFP)-reporter vectors together with a control lentiviral-CMV-EGFP, were tested by microscopy and flowcytometry for expression of EGFP after infection of human prostate cancer cells (LNCaP, PC-3, PC-3(hAR), and Du145 cells) and non-prostate cells (COS-1, HeLa, HeLa(hAR), and MCF-7 cells).


RESULTS
All cells infected in vitro with lentiviral-CMV vectors expressed EGFP, whereas with lentiviral-PB vectors (the most potent being Lv-ARR(2)PB), reporter expression was only observed in LNCaP cells with a small amount seen in androgen-independent PC-3 cells. Stable or transient transfection of androgen receptor only raised EGFP expression in prostate-derived cell lines, but did not change tumor specificity. With Lv-ARR(2)PB infected LNCaP cells, androgens regulated EGFP both in vitro and in vivo. After intra-tumor injection of this vector, EGFP expression was observed in LNCaP tumors, but not in A-549 lung or CaKi-2 kidney tumors.


CONCLUSIONS
Lv-ARR(2)PB may be an ideal vector for prostate-tumor targeting and for persistent, hormone-enhanced expression of a therapeutic gene to treat slow growing prostate tumors.
Yu
Duan
D
The Prostate Center at Vancouver General Hospital and the Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada.
Jia
William W
WW
Gleave
Martin E
ME
Nelson
Colleen C
CC
Rennie
Paul S
PS
D000727:Androgen-Binding Protein / Q000096:biosynthesis* / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D015316:Genetic Therapy; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D006801:Humans; D016086:Lentivirus / Q000235:genetics* / Q000472:pathogenicity; D008164:Luminescent Proteins / Q000096:biosynthesis; D008297:Male; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics*; D014407:Tumor Cells, Cultured
D000727:Androgen-Binding Protein; D008164:Luminescent Proteins; C027519:probasin; D049452:Green Fluorescent Proteins