Suppression of PI3K/Akt signaling by synthetic bichalcone analog TSWU-CD4 induces ER stress- and Bax/Bak-mediated apoptosis of cancer cells

Meng Liang Lin, Shih Shun Chen, Ren Yu Huang, Yao Cheng Lu, Yu Ren Liao, Mopuru Vijaya Bhaskar Reddy, Chuan Chun Lee, Tian Shung Wu

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Suppression of the activity of pro-apoptotic Bcl-2-family proteins frequently confers chemoresistance to many human cancer cells. Using subcellular fractionation, the ER calcium (Ca++) channel inhibitor dantrolene and small interfering RNA (siRNA) against Bax or Bak, we show that the new synthetic bichalcone analog TSWU-CD4 induces apoptosis in human cancer cells by releasing endoplasmic reticulum (ER)-stored Ca++ through ER/mitochondrial oligomerization of Bax/Bak. Blockade of the protein kinase RNA-like ER kinase or the unfolded protein response regulator glucose-regulated protein 78 expression by siRNA not only suppressed oligomeric Bax/Bak-mediated pro-caspase-12 cleavage and apoptosis but also resulted in an inhibition of Bcl-2 downregulation induced by TSWU-CD4. Induction of the ER oligomerization of Bax/Bak and apoptosis by TSWU-CD4 were suppressed by Bcl-2 overexpression. Inhibition of lipid raft-associated phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling by TSWU-CD4 induced ER stress- and oligomeric Bax/Bak-mediated apoptosis, which were substantially reversed by overexpression of the wt PI3K p85α subunit. Taken together, these results suggest that suppression of lipid raft-associated PI3K/Akt signaling is required for the ER stress-mediated apoptotic activity of Bax/Bak, which is responsible for the ability of TSWU-CD4-treated cancer cells to exit the ER-mitochondrial apoptotic cell death pathway.

Original languageEnglish
Pages (from-to)1637-1653
Number of pages17
JournalApoptosis
Volume19
Issue number11
DOIs
Publication statusPublished - 2014 Oct 14

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmaceutical Science
  • Clinical Biochemistry
  • Cell Biology
  • Biochemistry, medical
  • Cancer Research

Fingerprint Dive into the research topics of 'Suppression of PI3K/Akt signaling by synthetic bichalcone analog TSWU-CD4 induces ER stress- and Bax/Bak-mediated apoptosis of cancer cells'. Together they form a unique fingerprint.

Cite this