Elevated AKR1C3 expression promotes prostate cancer cell survival and prostate cell-mediated endothelial cell tube formation: implications for prostate cancer progression.
BACKGROUND
Aldo-keto reductase (AKR) 1C family member 3 (AKR1C3), one of four identified human AKR1C enzymes, catalyzes steroid, prostaglandin, and xenobiotic metabolism. In the prostate, AKR1C3 is up-regulated in localized and advanced prostate adenocarcinoma, and is associated with prostate cancer (PCa) aggressiveness. Here we propose a novel pathological function of AKR1C3 in tumor angiogenesis and its potential role in promoting PCa progression.


METHODS
To recapitulate elevated AKR1C3 expression in cancerous prostate, the human PCa PC-3 cell line was stably transfected with an AKR1C3 expression construct to establish PC3-AKR1C3 transfectants. Microarray and bioinformatics analysis were performed to identify AKR1C3-mediated pathways of activation and their potential biological consequences in PC-3 cells. Western blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and an in vitro Matrigel angiogenesis assays were applied to validate the pro-angiogenic activity of PC3-AKR1C3 transfectants identified by bioinformatics analysis.


RESULTS
Microarray and bioinformatics analysis suggested that overexpression of AKR1C3 in PC-3 cells modulates estrogen and androgen metabolism, activates insulin-like growth factor (IGF)-1 and Akt signaling pathways, as well as promotes tumor angiogenesis and aggressiveness. Levels of IGF-1 receptor (IGF-1R) and Akt activation as well as vascular endothelial growth factor (VEGF) expression and secretion were significantly elevated in PC3-AKR1C3 transfectants in comparison to PC3-mock transfectants. PC3-AKR1C3 transfectants also promoted endothelial cell (EC) tube formation on Matrigel as compared to the AKR1C3-negative parental PC-3 cells and PC3-mock transfectants. Pre-treatment of PC3-AKR1C3 transfectants with a selective IGF-1R kinase inhibitor (AG1024) or a non-selective phosphoinositide 3-kinases (PI3K) inhibitor (LY294002) abolished ability of the cells to promote EC tube formation.


CONCLUSIONS
Bioinformatics analysis followed by functional genomics demonstrated that AKR1C3 overexpression promotes angiogenesis and aggressiveness of PC-3 cells. These results also suggest that AKR1C3-mediated tumor angiogenesis is regulated by estrogen and androgen metabolism with subsequent IGF-1R and Akt activation followed by VEGF expression in PCa cells.
Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 N,E, 13th Street, Oklahoma City, Oklahoma 73104, USA.
Mikhail G
MG
Dozmorov
Joseph T
JT
Azzarello
Jonathan D
JD
Wren
Kar-Ming
KM
Fung
Qing
Q
Yang
Jeffrey S
JS
Davis
Robert E
RE
Hurst
Daniel J
DJ
Culkin
Trevor M
TM
Penning
Hsueh-Kung
HK
Lin
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival; D019295:Computational Biology; D013196:Dihydrotestosterone / Q000378:metabolism; D018450:Disease Progression; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D053263:Gene Regulatory Networks; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D009389:Neovascularization, Pathologic / Q000201:enzymology* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000098:blood supply / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism; D047488:Retinoid X Receptors / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D047428:Protein Kinase Inhibitors; D018167:Receptors, Calcitriol; D047488:Retinoid X Receptors; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D013196:Dihydrotestosterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D015096:3-Hydroxysteroid Dehydrogenases; D006911:Hydroxyprostaglandin Dehydrogenases; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt