Lentiviral vector neutral endopeptidase gene transfer suppresses prostate cancer tumor growth.
Neprilysin (neutral endopeptidase, NEP) is a cell surface peptidase whose expression is lost in approximately 50% of prostate cancers (PC). NEP normally functions to inactivate peptides such as bombesin and endothelin-1, and potentiates the effects of the PTEN tumor suppressor via a direct protein-protein interaction. NEP loss contributes to PC progression. We investigated the therapeutic efficacy of using a lentiviral vector system to restore NEP expression in PC cells. Third-generation lentiviral vectors encoding wild-type NEP (L-NEP) or green fluorescent protein (L-GFP) were introduced into NEP-deficient 22RV1 PC cells. Cells infected with L-NEP or L-GFP at a multiplicity of infection of 10 demonstrated NEP enzyme activity of 1171.2+/-4.9 and 17.2+/-5.3 pmol/microg/min (P<0.0001), respectively. Cell viability, proliferation and invasion were each significantly inhibited in 22RV1 cells expressing NEP compared with control cells infected with L-GFP (P<0.01). Analysis of known downstream effects of NEP showed NEP-expressing cells exhibiting decreased Akt and focal adhesion kinase phosphorylation and increased PTEN protein expression. Finally, injection of L-NEP into established 22RV1 xenograft tumors significantly inhibited tumor growth (P<0.01). These experiments demonstrate that lentiviral NEP gene transfer is a novel targeted strategy for the treatment of NEP-deficient PC.
Horiguchi
A
A
Urologic Oncology Research Laboratory, Department of Urology, Weill Medical College of Cornell University, New York, NY 10021, USA.
Zheng
R
R
Goodman
O B
OB
Shen
R
R
Guan
H
H
Hersh
L B
LB
Nanus
D M
DM
D000818:Animals; D002460:Cell Line; D004195:Disease Models, Animal; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness / Q000503:physiopathology*; D015260:Neprilysin / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000276:immunology / Q000628:therapy*; D023041:Xenograft Model Antitumor Assays
D015260:Neprilysin