Efficacy of osimertinib against EGFRvIII+ glioblastoma

Gustavo Chagoya, Shawn G. Kwatra, Cory W. Nanni, Callie M. Roberts, Samantha M. Phillips, Sarah Nullmeyergh, Samuel P. Gilmore, Ivan Spasojevic, David L. Corcoran, Christopher C. Young, Karla V. Ballman, Rohan Ramakrishna, Darren A. Cross, James M. Markert, Michael Lim, Mark R. Gilbert, Glenn J. Lesser, Madan M. Kwatra

Research output: Contribution to journalArticlepeer-review

Abstract

Epidermal Growth Factor Receptor variant III (EGFRvIII) is an active mutant form of EGFR that drives tumor growth in a subset of glioblastoma (GBM). It occurs in over 20% of GBMs, making it a promising receptor for small molecule targeted therapy. We hypothesize that poor penetration of the blood-brain barrier by previously tested EGFR-tyrosine kinase inhibitors (EGFR-TKIs) such as afateninb, erlotinib, gefitinib, and lapatinib played a role in their limited efficacy. The present study examined the effects of osimertinib (previously known as AZD9291) on EGFRvIII+ GBM models, both in vitro and in vivo. Therefore, a panel of six GBM stem cells (GSCs) expressing EGFRvIII+ was evaluated. The EGFRvIII+ GSC differed in the expression of EGFRvIII and other key genes. The GSC line D317, which expresses high levels of EGFRvIII and has robust tyrosine kinase activity, was selected for assessing osimertinib’s efficacy. Herein, we report that osimertinib inhibits the constitutive activity of EGFRvIII tyrosine kinase with high potency (<100 nM) while also inhibiting its downstream signaling. Further, osimertinib inhibited D317’s growth in vitro and in both heterotopic and orthotopic xenograft models. Additional preclinical studies are warranted to identify EGFRvIII+ GBM’s molecular signature most responsive to osimertinib.

Original languageEnglish (US)
Pages (from-to)2074-2082
Number of pages9
JournalOncotarget
Volume11
Issue number22
DOIs
StatePublished - Jun 1 2020

Keywords

  • EGFRvIII
  • Glioblastoma stem cells
  • Osimertinib
  • Tyrosine kinase
  • Xenografts

ASJC Scopus subject areas

  • Oncology

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