Predicting ROR1/BCL2 combination targeted therapy of small cell carcinoma of the lung

Cell Death Dis. 2021 Jun 4;12(6):577. doi: 10.1038/s41419-021-03855-w.

Abstract

Small cell lung cancer (SCLC) remains a deadly form of cancer, with a 5-year survival rate of less than 10 percent, necessitating novel therapies. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncofetal protein that is emerging as a therapeutic target and is co-expressed with BCL2 in multiple tumor types due to microRNA coregulation. We hypothesize that ROR1-targeted therapy is effective in small cell lung cancer and synergizes with therapeutic BCL2 inhibition. Tissue microarrays (TMAs) and formalin-fixed paraffin-embedded (FFPE) SCLC patient samples were utilized to determine the prevalence of ROR1 and BCL2 expression in SCLC. Eight SCLC-derived cell lines were used to determine the antitumor activity of a small molecule ROR1 inhibitor (KAN0441571C) alone and in combination with the BCL2 inhibitor venetoclax. The Chou-Talalay method was utilized to determine synergy with the drug combination. ROR1 and BCL2 protein expression was identified in 93% (52/56) and 86% (48/56) of SCLC patient samples, respectively. Similarly, ROR1 and BCL2 were shown by qRT-PCR to have elevated expression in 79% (22/28) and 100% (28/28) of SCLC patient samples, respectively. KAN0441571C displayed efficacy in 8 SCLC cell lines, with an IC50 of 500 nM or less. Synergy as defined by a combination index of <1 via the Chou-Talalay method between KAN0441571C and venetoclax was demonstrated in 8 SCLC cell lines. We have shown that ROR1 inhibition is synergistic with BCL2 inhibition in SCLC models and shows promise as a novel therapeutic target in SCLC.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / pharmacology*
  • Bridged Bicyclo Compounds, Heterocyclic / administration & dosage
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology*
  • Cell Line, Tumor
  • Drug Synergism
  • Humans
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Molecular Targeted Therapy
  • Protein Kinase Inhibitors / administration & dosage
  • Protein Kinase Inhibitors / pharmacology*
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Receptor Tyrosine Kinase-like Orphan Receptors / antagonists & inhibitors*
  • Receptor Tyrosine Kinase-like Orphan Receptors / biosynthesis
  • Receptor Tyrosine Kinase-like Orphan Receptors / genetics
  • Small Cell Lung Carcinoma / drug therapy*
  • Small Cell Lung Carcinoma / genetics
  • Small Cell Lung Carcinoma / metabolism
  • Sulfonamides / administration & dosage
  • Sulfonamides / pharmacology*
  • Survival Analysis

Substances

  • BCL2 protein, human
  • Bridged Bicyclo Compounds, Heterocyclic
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins c-bcl-2
  • Sulfonamides
  • ROR1 protein, human
  • Receptor Tyrosine Kinase-like Orphan Receptors
  • venetoclax