Evidence that activation of nuclear factor-kappaB is essential for the cytotoxic effects of doxorubicin and its analogues.
Several reports within the last 5 years have suggested that nuclear factor (NF)-kappaB activation suppresses apoptosis through expression of anti-apoptotic genes. In the present report, we provide evidence from four independent lines that NF-kappaB activation is required for the cytotoxic effects of doxorubicin. We used doxorubicin and its structural analogues WP631 and WP744, to demonstrate that anthracyclines activate NF-kappaB, and this activation is essential for apoptosis in myeloid (KBM-5) and lymphoid (Jurkat) cells. All three anthracyclines had cytotoxic effects against KBM-5 cells; analogue WP744, was most potent, with an IC(50) of 0.5 microM, and doxorubicin was least active, with an IC(50) of 2 microM. We observed maximum NF-kappaB activation at 1 microM with WP744 and at 50 microM with doxorubicin and WP631, and this activation correlated with the IkappaBalpha degradation. Because the anthracycline analogue (WP744), most active as a cytotoxic agent, was also most active in inducing NF-kappaB activation and the latter preceded the cytotoxic effects, suggests that NF-kappaB activation may mediate cytotoxicity. Second, receptor-interacting protein-deficient cells, which did not respond to doxorubicin-induced NF-kappaB activation, were also protected from the cytotoxic effects of all the three anthracyclines. Third, suppression of NF-kappaB activation by pyrrolidine dithiocarbamate, also suppressed the cytotoxic effects of anthracyclines. Fourth, suppression of NF-kappaB activation by NEMO-binding domain peptide, also suppressed the cytotoxic effects of the drug. Overall our results clearly demonstrate that NF-kappaB activation and IkappaBalpha degradation are early events activated by doxorubicin and its analogues and that they play a critical pro-apoptotic role.
Ashikawa
Kazuhiro
K
Cytokine Research Laboratory, Department of Bioimmunotherapy, M.D. Anderson Cancer Center, The University of Texas, 1515 Holcombe Boulevard, Box 143, Houston, TX 77030, USA.
Shishodia
Shishir
S
Fokt
Izabel
I
Priebe
Waldemar
W
Aggarwal
Bharat B
BB
D018943:Anthracyclines / Q000494:pharmacology; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D004273:DNA, Neoplasm / Q000187:drug effects / Q000378:metabolism; D003630:Daunorubicin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology*; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D019169:Jurkat Cells; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured
D018943:Anthracyclines; D000903:Antibiotics, Antineoplastic; D004273:DNA, Neoplasm; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D014157:Transcription Factors; C104426:WP 631; C451735:WP 744; D000072000:NF-KappaB Inhibitor alpha; D004317:Doxorubicin; D003630:Daunorubicin