Characterization of intracellular calcium mobilization by bombesin-related neuropeptides in PC-3 human prostate cancer cells.
BACKGROUND
The objective of this study was to characterize the calcium mobilizing activity of bombesin-related neuropeptides in PC-3 cells.


METHODS
Intracellular free Ca2+ concentration ([Ca2+]i) was measured following the administration of bombesin-related neuropeptides using spectrofluorometric monitoring of PC-3 cells loaded with Fura2/AM.


RESULTS
Individual neuropeptides induced a rapid rise in [Ca2+]i immediately after stimulation in similar fashion. When two different peptides were administered simultaneously, the [Ca2+]i changes were similar to that produced by each peptide alone. However, simultaneous addition of tyr4-bombesin 100 nM and 2% serum resulted in [Ca2+]i increase greater than either alone. Sequential stimulation by same or different peptides, was not able to induce another response. However, 6 hrs after the first stimulus, a second stimulus was able to induce a similar response.


CONCLUSIONS
The data indicate that all members of the bombesin-related family of neuropeptides are capable of triggering calcium mobilization in PC-3 cells via a similar signalling pathway. PC-3 cells become acutely desensitized to additional stimulation of neuropeptide. This desensitization is selective and reversible, requiring approximately 6 hrs for recovery.
Han
K
K
Department of Surgery (Urology), McGill University, Montreal, Quebec.
Viallet
J
J
Chevalier
S
S
Zheng
W
W
Bazinet
M
M
Aprikian
A G
AG
D001839:Bombesin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D004357:Drug Synergism; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D001839:Bombesin; D002118:Calcium