R(+)-Methanandamide Elicits a Cyclooxygenase-2-Dependent Mitochondrial Apoptosis Signaling Pathway in Human Neuroglioma Cells
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Cannabinoids have been associated with tumor regression and apoptosis of cancer cells. Recently, we have shown that R(+)-methanandamide (R(+)-MA) induces apoptosis of H4 human neuroglioma cells via a mechanism involving de novo expression of the cyclooxygenase-2 (COX-2) enzyme. The present study investigated a possible involvement of a mitochondrial-driven pathway in this process.
Cell death was determined by the WST-1 cell viability test, and changes in apoptotic parameters [i.e., release of mitochondrial cytochrome c, activation of caspases, cleavage of poly(ADP-ribose) polymerase (PARP)] were detected by Western blotting.
H4 cells treated with R(+)-MA showed typical signs of mitochondrial apoptosis, i.e., release of mitochondrial cytochrome c into the cytosol and activation of initiator caspase-9. Moreover, activation of the executor caspase-3 was observed following cannabinoid treatment. Cells were fully protected from apoptotic cell death by the caspase-3 inhibitor Ac-DEVD-CHO, indicating a crucial role for caspase-3 activation in R(+)-MA-elicited apoptosis. Furthermore, cleavage of the caspase-3 target protein PARP was registered. All of the aforementioned effects were substantially reduced by the selective COX-2 inhibitor celecoxib (1 μM) at a pharmacologically relevant, nonapoptotic concentration.
R(+)-MA-induced apoptosis is mediated via a mitochondrial-dependent pathway that becomes activated, at least in part, through up-regulation of the COX-2 enzyme.
Key Wordscyclooxygenase-2 human neuroglioma cells intrinsic apoptosis mitochondrial apoptosis R(+)-methanandamide
This study was supported by the Deutsche Forschungsgemeinschaft (HI 813/1-1 and SFB 539 TP BI.6).
- 17.Thornberry, N. A., Rano, T. A., Peterson, E. P., Rasper, D. M., Timkey, T., Garcia-Calvo, M., Houtzager, V. M., Nordstrom, P. A., Roy, S., Vaillancourt, J. P., Chapman, K. T., Nicholson, D. W. 1997A combinatorial approach defines specificities of members of the caspase family and granzyme B. Functional relationships established for key mediators of apoptosisJ. Biol. Chem.2721790717911CrossRefPubMedGoogle Scholar
- 18.Niiya, M., Niiya, K., Shibakura, M., Asaumi, N., Yoshida, C., Shinagawa, K., Teshima, T., Ishimaru, F., Ikeda, K., Tanimoto, M. 2004Involvement of ERK1/2 and p38 MAP kinase in doxorubicin-induced uPA expression in human RC-K8 lymphoma and NCI-H69 small cell lung carcinoma cellsOncology67310319CrossRefPubMedGoogle Scholar
- 26.Denkert, C., Furstenberg, A., Daniel, P. T., Koch, I., Kobel, M., Weichert, W., Siegert, A., Hauptmann, S. 2003Induction of G0/G1 cell cycle arrest in ovarian carcinoma cells by the anti-inflammatory drug NS-398, but not by COX-2-specific RNA interferenceOncogene2286538661CrossRefPubMedGoogle Scholar