Tumour biology and pathology

3PD - Co-targeting PIM1 or Src to overcome the limits of single MET inhibition

Authors
  • Ilaria Attili (IT)
  • Niki Karachaliou (ES)
  • Jillian Bracht (ES)
  • Jordi Berenguer (ES)
  • Carles Codony-Servat (ES)
  • Masaoki Ito (JP)
  • Massimo Rugge (IT)
  • Pier Franco Conte (IT)
  • Laura Bonanno (IT)
  • Rafael Rosell (ES)
Presenter
  • Ilaria Attili (IT)

Abstract

Background

Single MET inhibition has controversial effects in MET addicted tumors. Proviral integration site for Moloney murine leukemia virus-1 (PIM1) is activated upon MET inhibition in MET addicted cells. PIM1 drives the expression of receptor tyrosine kinases (RTKs). SHP2, a non-receptor protein tyrosine phosphatase, is central in RTKs signaling and in Src activation. We have shown that the overexpression of RTKs like AXL and the transmembrane protein CUB domain-containing protein-1 (CDCP1) as well as Src activation, are mechanisms of intrinsic resistance to EGFR inhibition in EGFR mutant lung cancer. We are now testing whether RTKs, SHP2 or CDCP1 expression and activation are driven by PIM1 or Src and cause resistance to MET inhibitors in MET addicted tumors.

Methods

We studied the inhibitory effect of the class I MET inhibitors tepotinib and savolitinib, the pan-PIM inhibitor AZD1208, and the Src inhibitor dasatinib in five MET addicted cell lines: 2 MET amplified lung cancer cells (EBC1 and H1993), 2 MET exon 14 mutant cells (Hs746T and H596) and a glioma cell line that carries the still not well recognized MET exon 7–8 splicing variant (E98). We assessed the effect of combined MET and PIM or MET and Src inhibition in cell viability and protein immunoblotting.

Results

All the cell lines were sensitive to single MET inhibition (except H596) and resistant to single AZD1208 or dasatinib. The combination of savolitinib or tepotinib with AZD1208 was synergistic in the EBC1 cell line and slightly synergistic or additive in the H1993, Hs746T and E98 cell lines. The combination of savolitinib or tepotinib with dasatinib was highly synergistic in all four cell lines. The treatment of EBC1 cells with tepotinib monotherapy was not able to inhibit AXL activation while it induced the activation of SHP2 and CDCP1. AXL, CDCP1 and SHP2 expression or activation were downregulated when tepotinib was combined with dasatinib.

Conclusions

Co-targeting PIM or Src with MET can be more effective than MET inhibition alone in MET addicted cell lines. Overexpression and activation of RTKs, CDCP1 and SHP2 can be mechanisms of resistance to single MET inhibition. The investigation of combinatorial strategies in MET addicted tumors, merits further investigation.

Legal entity responsible for the study

IGTP – Germans Trias i Pujol Research Institute, Badalona, Barcelona, Spain

Funding

Fundació Obra Social “La Caixa”

Disclosure

All authors have declared no conflicts of interest.

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