Identification of lenalidomide resistance pathways in myeloma and targeted resensitization using cereblon replacement, inhibition of STAT3 or targeting of IRF4

Yuan Xiao Zhu, Chang Xin Shi, Laura A. Bruins, Xuewei Wang, Daniel L. Riggs, Brooke Porter, Jonathan M. Ahmann, Cecilia Bonolo de Campos, Esteban D Braggio, Peter Leif Bergsagel, Alexander Keith Stewart

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

To understand immunomodulatory drug (IMiD) resistance in multiple myeloma (MM), we created isogenic human multiple myeloma cell lines (HMCLs) sensitive and resistant to lenalidomide, respectively. Four HMCLs were demonstrated to be resistant to all IMiDs including lenalidomide, pomalidomide, and CC-220, but not to Bortezomib. In three HMLCs (MM.1.SLenRes, KMS11LenRes and OPM2LenRes), CRBN abnormalities were found, including chromosomal deletion, point mutation, and low CRBN expression. The remaining HMCL, XG1LenRes, showed no changes in CRBN but exhibited CD147 upregulation and impaired IRF4 downregulation after lenalidomide treatment. Depletion of CD147 in XG1LenRes and three additional HMCLs had no significant impact on MM viability and lenalidomide response. Further analysis of XG1LenRes demonstrated increased IL6 expression and constitutive STAT3 activation. Inhibition of STAT3 with a selective compound (PB-1-102) re-sensitized XG1LenRes to lenalidomide. Since XG1LenRes harbors a truncated IRF4 that is not downregulated by lenalidomide, we targeted IRF4/MYC axis with a selective inhibitor of the bromodomain of CBP/EP300 (SGC-CBP30), which restored lenalidomide response in XG1LenRes. This strategy also appeared to be more broadly applicable as SGC-CBP30 could re-sensitize two resistant HMCLs with low but detectable CRBN expression to lenalidomide, suggesting that targeting CBP/E300 is a promising approach to restore IMiD sensitivity in MM with detectable CRBN expression.

Original languageEnglish (US)
Article number19
JournalBlood cancer journal
Volume9
Issue number2
DOIs
StatePublished - Feb 1 2019

ASJC Scopus subject areas

  • Hematology
  • Oncology

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