The IGF-1 receptor inhibitor picropodophyllin potentiates the anti-myeloma activity of a BH3-mimetic

Oncotarget. 2014 Nov 30;5(22):11193-208. doi: 10.18632/oncotarget.1933.

Abstract

The ABT-analogous 737, 263 and 199 are BH3 mimetics showing potent anti-myeloma (MM) activity, but only on defined molecular subgroups of MM patients presenting a Bcl-2high/Mcl-1low profile. IGF-1 is a major survival factor in MM regulating the expression of Bcl-2 proteins and might therefore be a resistance factor to these ABT-analogous. We first show that IGF-1 protected human MM cell lines (HMCLs) against ABT-737. Concurrently, the IGF-1 receptor inhibitor picropodophyllin (PPP) synergistically sensitized HMCL, primary human MM and murine 5T33MM cells to ABT-737 and ABT-199 by further decreasing cell viability and enhancing apoptosis. Knockdown of Bcl-2 by shRNA protected MM cells to ABT-737, while Mcl-1 shRNA sensitized the cells. PPP overcame the Bcl-2 dependency of ABT-737, but failed to completely overcome the protective effect of Mcl-1. In vivo, co-treatment of 5T33MM bearing mice significantly decreased tumor burden and prolonged overall survival both in a prophylactic and therapeutic setting. Interestingly, proteasome inhibitor resistant CD138- 5T33MM cells were more sensitive to ABT-737, whereas PPP alone targeted the CD138+ cells more effectively. After co-treatment, both subpopulations were targeted equally. Together, the combination of an IGF-1R inhibitor and an ABT-analogue displays synergistic anti-myeloma activity providing the rational for further (pre)clinical testing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology*
  • Apoptosis / drug effects
  • Biomimetic Materials / administration & dosage
  • Biomimetic Materials / pharmacology
  • Biphenyl Compounds / administration & dosage
  • Biphenyl Compounds / pharmacology*
  • Cell Line, Tumor
  • Drug Synergism
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Multiple Myeloma / drug therapy*
  • Multiple Myeloma / metabolism
  • Multiple Myeloma / pathology
  • Nitrophenols / administration & dosage
  • Nitrophenols / pharmacology*
  • Piperazines / administration & dosage
  • Piperazines / pharmacology
  • Podophyllotoxin / administration & dosage
  • Podophyllotoxin / analogs & derivatives*
  • Podophyllotoxin / pharmacology
  • Receptor, IGF Type 1 / antagonists & inhibitors*
  • Sulfonamides / administration & dosage
  • Sulfonamides / pharmacology*

Substances

  • ABT-737
  • Biphenyl Compounds
  • Nitrophenols
  • Piperazines
  • Sulfonamides
  • picropodophyllin
  • Receptor, IGF Type 1
  • Podophyllotoxin