Penta-acetyl geniposide-induced apoptosis involving transcription of NGF/p75 via MAPK-mediated AP-1 activation in C6 glioma cells.
We have demonstrated the herbal derivative penta-acetyl geniposide ((Ac)(5)GP) induces C6 glioma cell apoptosis through the critical sphingomyelinase (SMase)/nerve growth factor (NGF)/p75 and its downstream signals. It has been reported mitogen-activated protein kinase (MAPK) mediates NGF synthesis induced by SMase activation. In this study, ERK, p38 and JNK are shown to mediate (Ac)(5)GP-induced glioma cell apoptosis and elevation of NGF and p75. Treatment of PD98059 (ERK-specific inhibitor), SB203580 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor) decreases the elevation of NGF and p75 mRNA induced by (Ac)(5)GP, indicating possible transcription regulation via MAPKs. The results of nuclear extract blotting and EMSA further confirm (Ac)(5)GP maximally increases AP-1 and NF-kappaB DNA binding at 6h. Inhibition of ERK, p38 and JNK block the activation of AP-1 and NF-kappaB, suggesting these MAPKs are involved in (Ac)(5)GP-induced transcription regulation. We thereby used RT-PCR to analyze cells treated with (Ac)(5)GP, with or without AP-1 or NF-kappaB inhibitors. AP-1 inhibitor NDGA decreases NGF/p75 and expression of FasL and caspase 3 induced by (Ac)(5)GP, suggesting the importance of AP-1 in mediating NGF/p75 and their downstream apoptotic signals. However, FasL and caspase 3 do not change with the NF-kappaB inhibitor PDTC; NF-kappaB might be linked to other cellular events. Overall, we demonstrate that MAPK mediates (Ac)(5)GP-induced activation of AP-1, promoting the transcription of NGF/p75 and downstream apoptotic signals. These results further highlight the potential therapeutic effects of (Ac)(5)GP in chemoprevention or as an anti-tumor agent.
Peng
Chiung-Huei
CH
Department of Nursing, Hungkuang University, Sha Lu, Taichung, Taiwan.
Huang
Chien-Ning
CN
Hsu
Shu-Ping
SP
Wang
Chau-Jong
CJ
D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D024202:Electrophoretic Mobility Shift Assay; D005419:Flavonoids / Q000494:pharmacology; D032062:Gardenia / Q000737:chemistry; D005910:Glioma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005960:Glucosides / Q000737:chemistry / Q000633:toxicity*; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D057888:Iridoid Glucosides; D039823:Iridoids / Q000737:chemistry / Q000633:toxicity*; D007641:Keratolytic Agents / Q000494:pharmacology; D009637:Masoprocol / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015394:Molecular Structure; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D020932:Nerve Growth Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects
D000873:Anthracenes; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants; D005419:Flavonoids; D005960:Glucosides; D007093:Imidazoles; D057888:Iridoid Glucosides; D039823:Iridoids; D007641:Keratolytic Agents; D016328:NF-kappa B; D010446:Peptide Fragments; D011725:Pyridines; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; C432165:pyrazolanthrone; C074968:pentaacetyl geniposide; D009637:Masoprocol; D020932:Nerve Growth Factor; C051997:nerve growth factor (75-88); D020928:Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one