The calcimimetic R-568 induces apoptotic cell death in prostate cancer cells.
BACKGROUND
Increased serum level of parathyroid hormone (PTH) was found in metastatic prostate cancers. Calcimimetic R-568 was reported to reduce PTH expression, to suppress cell proliferation and to induce apoptosis in parathyroid cells. In this study, we investigated the effect of R-568 on cellular survival of prostate cancer cells.


METHODS
Prostate cancer cell lines LNCaP and PC-3 were used in this study. Cellular survival was determined with MTT, trypan blue exclusion and fluorescent Live/Death assays. Western blot assay was utilized to assess apoptotic events induced by R-568 treatment. JC-1 staining was used to evaluate mitochondrial membrane potential.


RESULTS
In cultured prostate cancer LNCaP and PC-3 cells, R-568 treatment significantly reduced cellular survival in a dose- and time-dependent manner. R-568-induced cell death was an apoptotic event, as evidenced by caspase-3 processing and PARP cleavage, as well as JC-1 color change in mitochondria. Knocking down calcium sensing receptor (CaSR) significantly reduced R-568-induced cytotoxicity. Enforced expression of Bcl-xL gene abolished R-568-induced cell death, while loss of Bcl-xL expression led to increased cell death in R-568-treated LNCaP cells,.


CONCLUSIONS
Taken together, our data demonstrated that calcimimetic R-568 triggers an intrinsic mitochondria-related apoptotic pathway, which is dependent on the CaSR and is modulated by Bcl-xL anti-apoptotic pathway.
Li
Huaifu
H
Department of Urology, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, PR China. lifuzh3@163.com
Ruan
Guofeng
G
Li
Zhijun
Z
Liu
Ziwei
Z
Zheng
Xiaoqing
X
Zheng
Hao
H
Cheng
Guangming
G
Li
Benyi
B
Zhan
Ming
M
D000814:Aniline Compounds / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis; D002118:Calcium / Q000819:agonists*; D016923:Cell Death; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000378:metabolism; D010627:Phenethylamines; D011437:Propylamines; D011471:Prostatic Neoplasms / Q000378:metabolism*; D014162:Transfection; D051020:bcl-X Protein / Q000378:metabolism
D000814:Aniline Compounds; C107873:N-(2-chlorophenylpropyl)-1-(3-methoxyphenyl)ethylamine; D010281:Parathyroid Hormone; D010627:Phenethylamines; D011437:Propylamines; D051020:bcl-X Protein; D002118:Calcium