Involvement of MCL1, c-myc, and cyclin D2 protein degradation in ponatinib-induced cytotoxicity against T315I(+) Ph+leukemia cells

Chisato Inoue, Sayaka Sobue, Yoshiyuki Kawamoto, Yuji Nishizawa, Masatoshi Ichihara, Akihiro Abe, Fumihiko Hayakawa, Motoshi Suzuki, Yoshinori Nozawa, Takahsi Murate

Research output: Contribution to journalArticle

Abstract

T315I mutation found in chronic myelogenous leukemia (CML) and Ph + ALL patients is the most serious one among resistance against BCR/ABL kinase inhibitors including imatinib and is only responsive to ponatinib (PNT). However, the novel strategy is required to reduce life-threatening adverse effects of PNT including ischemic cardiovascular disease. We examined the mechanism of PNT-induced cytotoxicity against a T315I(+) Ph + ALL cell line, TccY/Sr. PNT induced apoptosis (increased sub G1 cells, and cleaved caspase3 and PARP), and suppressed protein expression of MCL1, cyclin D2 and c-myc, which were reversed by a proteasome inhibitor, MG132, suggesting enhanced proteasomal degradation by PNT. Among BCL2 family inhibitors, MCL1 inhibitors (maritoclax and AZD5991) robustly induced cell death, showing the MCL1-dependent survival of TccY/Sr cells. Decreased MCL1 and c-myc expression by PNT was also observed in T315I(+) MEGA2/STIR cells. PNT suppressed PI3K activation followed by AKT inhibition and GSK3 dephosphorylation. PI3K/AKT inhibitors mimicked PNT, suggesting that PI3K/AKT signaling is important for survival of TccY/Sr cells. Moreover, GSK3 inhibitor (SB216763) reduced PNT-induced cytotoxicity and degradation of c-myc and MCL1. AZD5991 exhibited the synergistic action with PNT, anti-cancer drugs and venetoclax (BCL2 inhibitor), suggesting the utility of MCL1 inhibitor alone or in combination as a future clinical option for Ph + leukemia patients.

Original languageEnglish
Pages (from-to)1074-1080
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume525
Issue number4
DOIs
Publication statusPublished - 14-05-2020

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Involvement of MCL1, c-myc, and cyclin D2 protein degradation in ponatinib-induced cytotoxicity against T315I(+) Ph+leukemia cells'. Together they form a unique fingerprint.

  • Cite this