Monoclonal antibody to the six-transmembrane epithelial antigen of prostate 4 promotes apoptosis and inhibits proliferation and glucose uptake in human adipocytes.
We previously identified the six-transmembrane epithelial antigen of prostate (STEAP) 4 as a novel plasma membrane protein that is up-regulated in obese patients and may play a significant role in the development of human obesity. In this study, a STEAP4-specific antibody was used to characterize the biological functions of the STEAP4 protein in human adipocytes. Cell viability assays (Trypan Blue exclusion), CCK-8 assays and cell cycle analysis showed that the STEAP4 antibody inhibited pre-adipocyte proliferation. Morphological observations by electron microscopy and confocal laser microscopy, annexin V-FITC labeling, caspase-3 and caspase-8 activity assays as well as data from quantitative real-time RT-PCR (qPCR) further determined that the STEAP4 antibody could promote apoptosis in pre-adipocytes. Based on quantitative Oil Red O staining and the expression profiles of specific markers, we demonstrated that the STEAP4 antibody did not affect adipogenesis, but the 2-deoxy-d-[3H]-glucose uptake tests showed that it induced the insulin-stimulated glucose uptake in mature human adipocytes. In conclusion, our results demonstrated that the STEAP4 antibody does not influence human adipocyte differentiation, but it is likely that the STEAP4 protein regulates proliferation and apoptosis and plays an important role in modulating the insulin sensitivity of human adipocytes.
Department of Pediatrics, Nanjing Maternal and Child Health Hospital of Nanjing Medical University, No. 123 Tianfei Road, Nanjing, P.R. China.
Da-Ni
DN
Qin
Chun-Zhao
CZ
Kou
Yu-Hui
YH
Ni
Chun-Mei
CM
Zhang
Jin-Gai
JG
Zhu
Chun
C
Zhu
Yan-Ping
YP
Wang
Guan-Zhong
GZ
Zhu
Chunmei
C
Shi
Chen-Bo
CB
Ji
Xi-Rong
XR
Guo
D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000704:Analysis of Variance; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D048708:Cell Growth Processes / Q000187:drug effects; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000276:immunology*; D010088:Oxidoreductases / Q000276:immunology*; D012844:Sincalide / Q000378:metabolism
D000911:Antibodies, Monoclonal; D008565:Membrane Proteins; D010088:Oxidoreductases; C503310:STEAP4 protein, human; D005947:Glucose; D012844:Sincalide