Activation and role of MAP kinases in 15d-PGJ2-induced apoptosis in the human pancreatic cancer cell line MIA PaCa-2.
OBJECTIVE
We have previously reported that 15-deoxy-delta-prostaglandin J2 (15d-PGJ2), a potent ligand for peroxisome proliferator-activated receptor gamma (PPARgamma), induces caspase-mediated apoptosis in human pancreatic cancer cell lines. Mitogen-activated protein kinases (MAPKs) are known to regulate apoptosis in various cancers. The purpose of this study was to investigate the role of MAPKs (ERK, JNK, and p38) in 15d-PGJ2-induced pancreatic cancer cell apoptosis.


METHODS
The effect of 15d-PGJ2 on MAPK activity was investigated by kinase assays using the human pancreatic cancer cell line MIA PaCa-2. Western blot analysis was performed to analyze phosphorylation of MAPKs, activation of caspases and poly ADP-ribose polymerase (PARP) cleavage. Apoptosis was evaluated by caspase-3 enzymatic activity and DNA fragmentation assay.


RESULTS
15d-PGJ2 activated all 3 MAPKs in a dose- and time-dependent fashion. SB202190, an inhibitor of p38, prevented 15d-PGJ2-induced activation of caspase-8, -9, and -3 and significantly decreased apoptosis. This effect was potentiated by SP600125, an inhibitor of JNK, although SP600125 alone had no significant effect on 15d-PGJ2-induced apoptosis. In contrast, PD98059, an inhibitor of MEK, significantly increased sensitivity to 15d-PGJ2-induced apoptosis.


CONCLUSIONS
15d-PGJ2 stimulates proapoptotic and antiapoptotic MAPK pathways. Sensitivity to 15d-PGJ2-induced apoptosis is increased by ERK inhibition but decreased by inhibition of p38.
Hashimoto
Koji
K
Department of Surgery, The University of Texas Medical Branch, Galveston, Texas, USA.
Farrow
Buckminster J
BJ
Evers
B Mark
BM
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D006801:Humans; D008024:Ligands; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000502:physiology*; D047495:PPAR gamma / Q000819:agonists; D010190:Pancreatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology*
C097240:15-deoxy-delta(12,14)-prostaglandin J2; D000970:Antineoplastic Agents; D008024:Ligands; D047495:PPAR gamma; D020928:Mitogen-Activated Protein Kinases; D020169:Caspases; D015230:Prostaglandin D2