Rapid induction of apoptosis by combination of flavopiridol and tumor necrosis factor (TNF)-alpha or TNF-related apoptosis-inducing ligand in human cancer cell lines.
Flavopiridol is one of the first cyclin-dependent kinase inhibitors undergoing clinical tests. We found that the combination treatment of flavopiridol (100-500 nM) with tumor necrosis factor (TNF)-alpha (10 ng/ml) induced a rapid and eminent apoptosis, 20 +/- 5% in 6-h treatment, in a human non-small cell lung carcinoma cell line, A549, as determined by the increase of sub-G(1) fraction in flow cytometry. A similar observation was also made in human colon cancer cell lines, HCT-116 and HCT-15, but not in Rat2, a rat fibroblast cell line. In A549 cells, the cytotoxic synergy by the combination treatment involved the activation of caspase-1, caspase-3, and caspase-8 and generated huge chromosomal degradation. The treatment schedules were so important that only the treatments of flavopiridol concomitantly with or followed by TNF-alpha showed the pronounced apoptosis in A549 cells. Prior treatment of TNF-alpha inhibited the apoptosis by the following combination treatment, leading to little cell death. Yet, such inhibition was reversed when 100 microM of 5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole, a transcription inhibitor, was present during the TNF-alpha pretreatment, suggesting that the inhibitory pretreatment of TNF-alpha might involve antiapoptotic gene expression at the transcriptional level. TNF-alpha treatment resulted in nuclear factor (NF)-kappa B activation, revealed by NF-kappa B activity reporter assay. In contrast, flavopiridol was found to inhibit the NF-kappa B-dependent gene transcription, which might give an explanation for the synergistic effect of flavopiridol with TNF-alpha. TNF-related apoptosis-inducing ligand (TRAIL; 100 ng/ml) also caused a rapid and strong cytotoxic synergy with flavopiridol. In contrast to TNF-alpha, however, all of the treatment sequences supported the synergy by TRAIL and flavopiridol. The combination of flavopiridol with TNF-alpha or TRAIL may be of use for the development in cancer therapy.
Kim
Dong-Myung
DM
LG Life Sciences, Ltd./R&D Park, Drug Discovery Institute, Daejeon, 305-380, Korea.
Koo
Sun-Young
SY
Jeon
Kiwan
K
Kim
Min Hyung
MH
Lee
Jinho
J
Hong
Chang Yong
CY
Jeong
ShinWu
S
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D018288:Carcinoma, Small Cell / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D005419:Flavonoids / Q000008:administration & dosage; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D008562:Membrane Glycoproteins / Q000008:administration & dosage; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D010880:Piperidines / Q000008:administration & dosage; D051381:Rats; D011994:Recombinant Proteins / Q000008:administration & dosage; D053221:TNF-Related Apoptosis-Inducing Ligand; D015533:Transcriptional Activation / Q000187:drug effects; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage
D051017:Apoptosis Regulatory Proteins; D061945:Caspase Inhibitors; D005419:Flavonoids; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D010880:Piperidines; D011994:Recombinant Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505655:Tnfsf10 protein, rat; D014409:Tumor Necrosis Factor-alpha; C077990:alvocidib; D020169:Caspases