| Title | Epothilones induce human colon cancer SW620 cell apoptosis via the tubulin polymerization independent activation of the nuclear factor-{kappa}B/I{kappa}B kinase signal pathway. | | Author(s) | Lee SH, Son SM, Son DJ, Kim SM, Kim TJ, Song S, Moon DC, Lee HW, Ryu JC, Yoon DY, Hong JT | | Institution | College of Pharmacy, Chungbuk National University, 410 SungBong-Ro, Heungduk-gu, Cheongju, Chungbuk 361-763, Korea. jinthong@chungbuk.ac.kr. | | Source | Mol Cancer Ther 2007 Oct; 6(10):2786-97. | | Abstract | Molecular mechanisms underlying epothilone-induced apoptotic cell death were investigated in SW620 human colon cancer cells. Treatment with epothilone B and D at different concentrations (1-100 nmol/L) dose-dependently inhibited cell growth and caused cell cycle arrest at G(2)-M, which was followed by apoptosis. Consistent with this induction of apoptotic cell death, epothilone B and D enhanced the constitutional activation of nuclear factor-kappaB (NF-kappaB) via IkappaB degradation through IkappaB kinase (IKKalpha and IKKbeta) activation, and this resulted in p50 and p65 translocation to the nucleus. Moreover, cells treated with sodium salicylic acid, an IKK inhibitor, or transiently transfected with mutant IKKalpha and beta did not show epothilone-induced cell growth inhibition or p50 translocation, although p65 was still translocated to the nucleus. Treatment with epothilone B and D also enhanced beta-tubulin polymerization and the formation of p50/beta-tubulin complex. However, beta-tubulin polymerization was not inhibited in the cells treated by sodium salicylic acid or transiently transfected with mutant IKKalpha and beta. Moreover, epothilone B and D increased the expressions of NF-kappaB-dependent apoptotic cell death regulatory genes, i.e., Bax, p53, and the active form of caspase-3, but reduced Bcl-2 expression, and these actions were partially reversed by salicylic acid. In addition, caspase-3 inhibitor reduced epothilone B-induced cell death and NF-kappaB activation. These findings suggest that the activation of NF-kappaB/IKK signals plays an important role in the epothilone-induced apoptotic cell death of SW620 colon cancer cells in a tubulin polymerization-independent manner. [Mol Cancer Ther 2007;6(10):2786-97]. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 17938270 |
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