Open Access

XIAP inhibits mature Smac-induced apoptosis by degrading it through ubiquitination in NSCLC

  • Authors:
    • Sida Qin
    • Chengcheng Yang
    • Boxiang Zhang
    • Xiang Li
    • Xin Sun
    • Gang Li
    • Jing Zhang
    • Guodong Xiao
    • Xiao Gao
    • Guanghong Huang
    • Peili Wang
    • Hong Ren
  • View Affiliations

  • Published online on: July 27, 2016     https://doi.org/10.3892/ijo.2016.3634
  • Pages: 1289-1296
  • Copyright: © Qin et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

X-linked inhibitor of apoptosis protein (XIAP) and second mitochondrial-derived activator of caspase (Smac) are two important prognostic biomarkers for cancer. They are negatively correlated in many types of cancer. However, their relationship is still unknown in lung cancer. In the present study, we found that there was a negative correlation between Smac and XIAP at the level of protein but not mRNA in NSCLC patients. However, XIAP overexpression had no effect on degrading endogenous Smac in lung cancer cell lines. Therefore, we constructed plasmids with full length of Smac (fSmac) and mature Smac (mSmac) which located in cytoplasm instead of original mitochondrial location, and was confirmed by immunofluorescence. Subsequently, we found that mSmac rather than fSmac was degraded by XIAP and inhibited cell viability. CHX chase assay and ubiquitin assay were performed to illustrate XIAP degraded mSmac through ubiquitin pathway. Overexpression of XIAP partially reverted apoptotic induction and cell viability inhibition by mSmac, which was due to inhibiting caspase-3 activation. In nude mouse xenograft experiments, mSmac inhibited Ki-67 expression and slowed down lung cancer growth, while XIAP partially reversed the effect of mSmac by degrading it. In conclusion, XIAP inhibits mature Smac-induced apoptosis by degrading it through ubiquitination in NSCLC.
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October-2016
Volume 49 Issue 4

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Copy and paste a formatted citation
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Spandidos Publications style
Qin S, Yang C, Zhang B, Li X, Sun X, Li G, Zhang J, Xiao G, Gao X, Huang G, Huang G, et al: XIAP inhibits mature Smac-induced apoptosis by degrading it through ubiquitination in NSCLC. Int J Oncol 49: 1289-1296, 2016.
APA
Qin, S., Yang, C., Zhang, B., Li, X., Sun, X., Li, G. ... Ren, H. (2016). XIAP inhibits mature Smac-induced apoptosis by degrading it through ubiquitination in NSCLC. International Journal of Oncology, 49, 1289-1296. https://doi.org/10.3892/ijo.2016.3634
MLA
Qin, S., Yang, C., Zhang, B., Li, X., Sun, X., Li, G., Zhang, J., Xiao, G., Gao, X., Huang, G., Wang, P., Ren, H."XIAP inhibits mature Smac-induced apoptosis by degrading it through ubiquitination in NSCLC". International Journal of Oncology 49.4 (2016): 1289-1296.
Chicago
Qin, S., Yang, C., Zhang, B., Li, X., Sun, X., Li, G., Zhang, J., Xiao, G., Gao, X., Huang, G., Wang, P., Ren, H."XIAP inhibits mature Smac-induced apoptosis by degrading it through ubiquitination in NSCLC". International Journal of Oncology 49, no. 4 (2016): 1289-1296. https://doi.org/10.3892/ijo.2016.3634