Brefeldin A induces p53-independent apoptosis in primary cultures of human prostatic cancer cells.
OBJECTIVE
The objective of this study was to investigate growth-inhibitory and apoptotic activity of the experimental antitumor drug, brefeldin A (BFA), on primary cultures of human epithelial cells derived from prostatic adenocarcinomas.


METHODS
Clonal assays were performed to evaluate the effects of BFA on growth of prostatic cancer cell strains. Loss of cell viability in response to BFA was assessed by trypan blue exclusion. Induction of apoptosis by BFA was evaluated by morphologic criteria, electrophoretic assay of DNA fragmentation, and a cell death ELISA. Immunoblots were used to monitor p53 and pRB expression in response to BFA.


RESULTS
BFA was growth-inhibitory at a half-maximal concentration of 5 ng./ml. (18 nM). Morphological manifestations of apoptosis were evident by 24 hours of treatment. Cell viability declined and the cell death ELISA indicated an 18-fold increase in apoptosis in BFA-treated versus untreated cells at 48 hours. DNA fragmentation was also seen at 48 hours. Levels of p53 were not altered by BFA, but pRB was maintained in a hypophosphorylated state by BFA treatment.


CONCLUSIONS
BFA is a potent inducer of apoptosis in prostatic cancer cells via a p53-independent mechanism. Cells derived from low-grade as well as high-grade cancers responded similarly to BFA. Since p53-mediated pathways of apoptosis may frequently be abrogated in prostatic cancer cells, agents such as BFA that induce p53-independent cell death may be promising candidates for chemotherapeutic agents.
Wallen
E
E
Department of Urology, Stanford University Medical Center, CA 94305-5118, USA.
Sellers
R G
RG
Peehl
D M
DM
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D020126:Brefeldin A / Q000627:therapeutic use*; D016923:Cell Death / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells / Q000187:drug effects; D004396:Coloring Agents; D053938:DNA Fragmentation; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000187:drug effects; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D008297:Male; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D011500:Protein Synthesis Inhibitors / Q000627:therapeutic use*; D016160:Retinoblastoma Protein / Q000187:drug effects; D014343:Trypan Blue; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects
D000970:Antineoplastic Agents; D004396:Coloring Agents; D011500:Protein Synthesis Inhibitors; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D020126:Brefeldin A; D014343:Trypan Blue