Importance of C16 ceramide accumulation during apoptosis in prostate cancer cells.
OBJECTIVE
Adenocarcinoma of the prostate is one of the most frequently diagnosed non-cutaneous cancers and the second leading cause of cancer-related deaths among men in the United States. To fully understand the role of ceramide during apoptosis induced by androgen ablation, we modified the levels of intracellular ceramide by pharmacological agents as well as through serum deprivation in androgen-dependent and independent cell lines.


METHODS
Ceramide levels were modified using N-oleoylethanolamine (NOE), sphingosine-1-phosphate (S1P) as well as through serum deprivation, in LNCaP, DU145 and PC-3 prostate cancer cells. Various methods including nonyl acridine orange staining, propidium iodide staining/cell cycle analysis and lipid analysis were utilized.


RESULTS
Our results demonstrate that the inhibition of acid ceramidase by NOE enhances the intracellular ceramide levels induced by androgen ablation in androgen-dependent LNCaP cells, and is accompanied by an increase in apoptotic cells. Sphingosine 1-phosphate had no effect in rescuing LNCaP cells from apoptosis induced by androgen ablation. Our results also show that serum deprivation causes intracellular ceramide accumulation and apoptosis in androgen-independent prostate cancer cells.


CONCLUSIONS
Our studies indicate that the increase in intracellular ceramide itself, but not the balance between ceramide and S1P, determines whether LNCaP cells undergo apoptosis. Our results also show that the increase in intracellular ceramide strongly correlates with apoptosis induced by serum deprivation even in androgen-independent prostate cancer cell lines.
Department of Surgery/Division of Surgical Oncology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219, USA.
Masatoshi
M
Eto
Jaafar
J
Bennouna
Oriana C
OC
Hunter
Michael T
MT
Lotze
Andrew A
AA
Amoscato
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology*; D000726:Androgen Antagonists / Q000494:pharmacology; D017209:Apoptosis; D045744:Cell Line, Tumor; D002518:Ceramides / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*
D000726:Androgen Antagonists; D002518:Ceramides; C097760:N-palmitoylsphingosine