The Bcl-2-xL inhibitor ABT-263 increases the stability of Mcl-1 mRNA and protein in hepatocellular carcinoma cellsReport as inadecuate




The Bcl-2-xL inhibitor ABT-263 increases the stability of Mcl-1 mRNA and protein in hepatocellular carcinoma cells - Download this document for free, or read online. Document in PDF available to download.

Molecular Cancer

, 13:98

First Online: 30 April 2014Received: 25 October 2013Accepted: 24 April 2014DOI: 10.1186-1476-4598-13-98

Cite this article as: Wang, B., Ni, Z., Dai, X. et al. Mol Cancer 2014 13: 98. doi:10.1186-1476-4598-13-98

Abstract

BackgroundHepatocellular carcinoma HCC is one of the major causes of mortality. ABT-263 is a newly synthesized, orally available Bcl-2-xL inhibitor that shows promising efficacy in HCC therapy. ABT-263 inhibits the anti-apoptotic activity of Bcl-2 and Bcl-xL, but not Mcl-1. Previous reports have shown that ABT-263 upregulates Mcl-1 in various cancer cells, which contributes to ABT-263 resistance in cancer therapy. However, the associated mechanisms are not well known.

MethodsWestern blot, RNAi and CCK-8 assays were used to investigate the relationship between Mcl-1 upregulation and ABT-263 sensitivity in HCC cells. Real-time PCR and Western blot were used to detect Mcl-1 mRNA and protein levels. Luciferase reporter assay and RNA synthesis inhibition assay were adopted to analyze the mechanism of Mcl-1 mRNA upregulation. Western blot and the inhibition assays for protein synthesis and proteasome were used to explore the mechanisms of ABT-263-enhanced Mcl-1 protein stability. Trypan blue exclusion assay and flow cytometry were used to examine cell death and apoptosis.

ResultsABT-263 upregulated Mcl-1 mRNA and protein levels in HCC cells, which contributes to ABT-263 resistance. ABT-263 increased the mRNA level of Mcl-1 in HCC cells by enhancing the mRNA stability without influencing its transcription. Furthermore, ABT-263 increased the protein stability of Mcl-1 through promoting ERK- and JNK-induced phosphorylation of Mcl-1 and increasing the Akt-mediated inactivation of GSK-3β. Additionally, the inhibitors of ERK, JNK or Akt sensitized ABT-263-induced apoptosis in HCC cells.

ConclusionsABT-263 increases Mcl-1 stability at both mRNA and protein levels in HCC cells. Inhibition of ERK, JNK or Akt activity sensitizes ABT-263-induced apoptosis. This study may provide novel insights into the Bcl-2-targeted cancer therapeutics.

KeywordsABT-263 Mcl-1 Stability HCC Electronic supplementary materialThe online version of this article doi:10.1186-1476-4598-13-98 contains supplementary material, which is available to authorized users.

Bin Wang, Zhenhong Ni contributed equally to this work.

Download fulltext PDF



Author: Bin Wang - Zhenhong Ni - Xufang Dai - Liyan Qin - Xinzhe Li - Liang Xu - Jiqin Lian - Fengtian He

Source: https://link.springer.com/







Related documents