The online version of this article (doi:10.1186/1475-2867-12-54) contains supplementary material, which is available to authorized users.
Qilin Wang, Wendong Sun contributed equally to this work.
The authors declare that they have no competing interests.
XGL and LS conducted the project design. QLW, WDS, XXH, TLL and LS conducted the experiments and data analysis. QL W and XG L drafted the manuscript. XG L managed the funding acquisition, supervised the project and was involved in interpretation of data and revision of the manuscript. All authors have contributed and approved the final manuscript.
Cellular FLICE-Inhibitory Protein (long form, c-FLIPL) is a critical negative regulator of death receptor-mediated apoptosis. Overexpression of c-FLIPL has been reported in many cancer cell lines and is associated with chemoresistance. In contrast, down-regulation of c-FLIP may drive cancer cells into cellular apoptosis. This study aims to demonstrate that inhibition of the heat shock protein 90 (Hsp90) either by inhibitors geldanamycin/17-N-Allylamino-17-demethoxygeldanamycin (GA/17-AAG) or siRNA technique in human lung cancer cells induces c-FLIPL degradation and cellular apoptosis through C-terminus of Hsp70-interacting protein (CHIP)-mediated mechanisms.
Calu-1 and H157 cell lines (including H157-c-FLIPL overexpressing c-FLIPL and control cell H157-lacZ) were treated with 17-AAG and the cell lysates were prepared to detect the given proteins by Western Blot and the cell survival was assayed by SRB assay. CHIP and Hsp90 α/β proteins were knocked down by siRNA technique. CHIP and c-FLIPL plasmids were transfected into cells and immunoprecipitation experiments were performed to testify the interactions between c-FLIPL, CHIP and Hsp90.
c-FLIPL down-regulation induced by 17-AAG can be reversed with the proteasome inhibitor MG132, which suggested that c-FLIPL degradation is mediated by a ubiquitin-proteasome system. Inhibition of Hsp90α/β reduced c-FLIPL level, whereas knocking down CHIP expression with siRNA technique inhibited c-FLIPL degradation. Furthermore, c-FLIPL and CHIP were co-precipitated in the IP complexes. In addition, overexpression of c-FLIPL can rescue cancer cells from apoptosis. When 17-AAG was combined with an anti-cancer agent celecoxib(CCB), c-FLIPL level declined further and there was a higher degree of caspase activation.
We have elucidated c-FLIPL degradation contributes to apoptosis induced by Hsp90 inhibition, suggesting c-FLIP and Hsp90 may be the promising combined targets in human lung cancer treatment.
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Salon C, Eymin B, Micheau O, Chaperot L, Plumas J, Brambilla C, Brambilla E, Gazzeri S: E2F1 induces apoptosis and sensitizes human lung adenocarcinoma cells to death-receptor-mediated apoptosis through specific downregulation of c-FLIP(short). Cell Death Differ. 2006, 13: 260-272. 10.1038/sj.cdd.4401739. CrossRefPubMed
Zong H, Yin B, Chen J, Ma B, Cai D, He X: Over-expression of c-FLIP confers the resistance to TRAIL-induced apoptosis on gallbladder carcinoma, Tohoku. J Exp Med. 2009, 217: 203-208.
Park MA, Zhang G, Mitchell C, Rahmani M, Hamed H, Hagan MP, Yacoub A, Curiel DT, Fisher PB, Grant S, Dent P: Mitogen-activated protein kinase kinase 1/2 inhibitors and 17-allylamino-17-demethoxygeldanamycin synergize to kill human gastrointestinal tumor cells in vitro via suppression of c-FLIP-s levels and activation of CD95. Mol Cancer Ther. 2008, 7: 2633-2648. 10.1158/1535-7163.MCT-08-0400. PubMedCentralCrossRefPubMed
Chen S, Liu X, Yue P, Schönthal AH, Khuri FR, Sun SY: CCAAT/enhancer binding protein homologous protein-dependent death receptor 5 induction and ubiquitin/proteasome-mediated cellular FLICE-inhibitory protein down-regulation contribute to enhancement of tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis by dimethyl-celecoxib in human non small-cell lung cancer cells. Mol Pharmacol. 2007, 72: 1269-1279. 10.1124/mol.107.037465. CrossRefPubMed
Sun SY, Yue P, Dawson MI, Shroot B, Michel S, Lamph WW, Heyman RA, Teng M, Chandraratna RA, Shudo K, Hong WK, Lotan R: Differential effects of synthetic nuclear retinoid receptor-selective retinoids on the growth of human non small cell lung carcinoma cells. Cancer Res. 1997, 57: 4931-4939. PubMed
Chatterjee M, Jain S, Stühmer T, Andrulis M, Ungethüm U, Kuban RJ, Lorentz H, Bommert K, Topp M, Krämer D, Müller-Hermelink HK, Einsele H, Greiner A, Bargou RC: STAT3 and MAPK signaling maintain overexpression of heat shock proteins 90alpha and beta in multiple myeloma cells, which critically contribute to tumor-cell survival. Blood. 2007, 109: 720-728. 10.1182/blood-2006-05-024372. CrossRefPubMed
- Down-regulation of cellular FLICE-inhibitory protein (Long Form) contributes to apoptosis induced by Hsp90 inhibition in human lung cancer cells
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