Ectopic expression of neurotrophic peptide derived from saposin C increases proliferation and upregulates androgen receptor expression and transcriptional activity in human prostate cancer cells.
OBJECTIVE
To determine the effects of the functional domain of saposin C (neurotrophic peptide [NP]) on androgen receptor (AR) expression and transcriptional activity.


METHODS
We constructed DNA vectors expressing NP or a chimeric peptide of the viral TAT transduction domain and NP (TAT-NP) using gene cloning technology. The effects of ectopic expression of NP or TAT-NP on cell growth were examined by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot, transient transfection and reporter gene assays were used to determine the effects of NP on AR expression and activation.


RESULTS
NP stimulated proliferation of androgen responsive LNCaP cells in the absence of androgens. RT-PCR and Western blot analyses showed that ectopic expression of NP resulted in induction of AR gene expression, and that the NP-stimulated expression of AR could be synergistically enhanced in the presence of androgens. Furthermore, reporter gene assay results showed that NP could enhance AR transactivation by increasing androgen-inducible gene reporter activity.


CONCLUSIONS
We provided evidence that ectopic expression of saposin C-originated NP could upregulate AR gene expression and activate the AR transcriptional function in an androgen-independent manner in prostate cancer cells.
Ding
Yan
Y
Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, China. lyuanhq@sdu.edu.cn
Yuan
Hui-Qing
HQ
Kong
Feng
F
Hu
Xiao-Yan
XY
Ren
Kai
K
Cai
Jie
J
Wang
Xiao-Ling
XL
Young
Charles Y F
CY
D002455:Cell Division; D045744:Cell Line, Tumor; D004273:DNA, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors; D006801:Humans; D007700:Kinetics; D008297:Male; D009414:Nerve Growth Factors / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D011944:Receptors, Androgen / Q000235:genetics*; D015183:Restriction Mapping; D020133:Reverse Transcriptase Polymerase Chain Reaction; D049231:Saposins / Q000378:metabolism*; D014158:Transcription, Genetic; D015854:Up-Regulation
D004273:DNA, Neoplasm; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D011944:Receptors, Androgen; D049231:Saposins