Pim kinase inhibitors sensitize prostate cancer cells to apoptosis triggered by Bcl-2 family inhibitor ABT-737

Jin H. Song, Andrew S. Kraft

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Pim serine/threonine kinases contribute to prostate tumorigenesis and therapeutic resistance, yet Pim kinase inhibitors seem to have only limited effects on prostate cancer cell survival. Because overexpression of Bcl-2 family members are implicated in chemotherapeutic resistance in prostate cancer, we investigated the cooperative effects of Pim kinase inhibition with ABT-737, a small molecule antagonist of Bcl-2 family members. Strikingly, the addition of ABT-737 to Pim inhibitors triggered a robust apoptosis of prostate cancer cells in vitro and in vivo. Pim inhibitors decreased levels of the Bcl-2 family member Mcl-1, both by blocking 5′-cap dependent translation and decreasing protein half life. In addition, Pim inhibition transcriptionally increased levels of the BH3 protein Noxa by activating the unfolded protein response (UPR), lead to eIF-2α phosphorylation and increased expression of CHOP. Increased levels of Noxa also inactivated the remaining levels of Mcl-1 protein activity. Notably, these specific protein changes were essential to the apoptotic process because ABT-737 did not inhibit Mcl-1 protein activity and Mcl-1 overexpression blocked the apoptotic activity of ABT-737. Our results therefore suggest that this combination treatment could be developed as a potential therapy for human prostate cancer where overexpression of Pim kinases and antiapoptotic Bcl-2 family members drives tumor cell resistance to current anticancer therapies.

Original languageEnglish (US)
Pages (from-to)294-303
Number of pages10
JournalCancer Research
Volume72
Issue number1
DOIs
StatePublished - Jan 1 2012
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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