beta2-microglobulin is a signaling and growth-promoting factor for human prostate cancer bone metastasis.
The protein factor beta2-microglobulin (beta2M), purified from the conditioned medium of human prostate cancer cell lines, stimulated growth and enhanced osteocalcin (OC) and bone sialoprotein (BSP) gene expression in human prostate cancer cells by activating a cyclic AMP (cAMP)-dependent protein kinase A signaling pathway. When beta2M was overexpressed in prostate cancer cells, it induced explosive tumor growth in mouse bone through increased phosphorylated cAMP-responsive element binding protein (CREB) and activated CREB target gene expression, including OC, BSP, cyclin A, cyclin D1, and vascular endothelial growth factor. Interrupting the beta2M downstream signaling pathway by injection of the beta2M small interfering RNA liposome complex produced an effective regression of previously established prostate tumors in mouse bone through increased apoptosis as shown by immunohistochemistry and activation of caspase-9, caspase-3, and cleavage of poly(ADP-ribose) polymerase. These results suggest that beta2M signaling is an attractive new therapeutic target for the treatment of lethal prostate cancer bone metastasis.
Huang
Wen-Chin
WC
Molecular Urology and Therapeutics Program, Department of Urology and Winship Cancer Institute, Microchemical and Proteomics Facility, and Divison of Endocrinology and Metabolism and Lipids, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Wu
Daqing
D
Xie
Zhihui
Z
Zhau
Haiyen E
HE
Nomura
Takeo
T
Zayzafoon
Majd
M
Pohl
Jan
J
Hsieh
Chia-Ling
CL
Weitzmann
M Neale
MN
Farach-Carson
Mary C
MC
Chung
Leland W K
LW
D000818:Animals; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism / Q000556:secondary*; D048708:Cell Growth Processes / Q000502:physiology; D045744:Cell Line, Tumor; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D001613:beta 2-Microglobulin / Q000096:biosynthesis / Q000378:metabolism*
D017362:Cyclic AMP Response Element-Binding Protein; D012333:RNA, Messenger; D001613:beta 2-Microglobulin; D015675:Osteocalcin; D017868:Cyclic AMP-Dependent Protein Kinases