PI3Kδ inhibitor, GS-1101 (CAL-101), attenuates pathway signaling, induces apoptosis, and overcomes signals from the microenvironment in cellular models of Hodgkin lymphoma

Blood. 2012 Feb 23;119(8):1897-900. doi: 10.1182/blood-2011-10-386763. Epub 2011 Dec 30.

Abstract

GS-1101 (CAL-101) is an oral PI3Kδ-specific inhibitor that has shown preclinical and clinical activity in non-Hodgkin lymphoma and chronic lymphocytic leukemia. To investigate the potential role of PI3Kδ in Hodgkin lymphoma (HL), we screened 5 HL cell lines and primary samples from patients with HL for PI3Kδ isoform expression and constitutive PI3K pathway activation. Inhibition of PI3Kδ by GS-1101 resulted in the inhibition of Akt phosphorylation. Cocultures with stroma cells induced Akt activation in HL cells, and this effect was blocked by GS-1101. Conversely, production of the stroma-stimulating chemokine, CCL5, by HL cells was reduced by GS-1101. GS-1101 also induced dose-dependent apoptosis of HL cells at 48 hours. Reductions in cell viability and apoptosis were enhanced when combining GS-1101 with the mTOR inhibitor everolimus. Our findings suggest that excessive PI3Kδ activity is characteristic in HL and support clinical evaluation of GS-1101, alone and in combination, as targeted therapy for HL.

MeSH terms

  • Apoptosis / drug effects*
  • Cell Cycle Checkpoints / drug effects
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cellular Microenvironment / drug effects*
  • Chemokine CCL5 / metabolism
  • Class Ia Phosphatidylinositol 3-Kinase / metabolism
  • Dose-Response Relationship, Drug
  • Hodgkin Disease / enzymology
  • Hodgkin Disease / pathology
  • Humans
  • Immunoblotting
  • Immunohistochemistry
  • Phosphoinositide-3 Kinase Inhibitors
  • Purines / pharmacology*
  • Quinazolinones / pharmacology*
  • Signal Transduction / drug effects*
  • Tissue Array Analysis

Substances

  • CCL5 protein, human
  • Chemokine CCL5
  • Phosphoinositide-3 Kinase Inhibitors
  • Purines
  • Quinazolinones
  • Class Ia Phosphatidylinositol 3-Kinase
  • idelalisib