Afatinib and Temozolomide combination inhibits tumorigenesis by targeting EGFRvIII-cMet signaling in glioblastoma cells

Abstract

Background Glioblastoma (GBM) is an aggressive brain tumor with universal recurrence and poor prognosis. The recurrence is largely driven by chemoradiation resistant cancer stem cells (CSCs). Epidermal growth factor receptor (EGFR) and its mutant EGFRvIII are amplified in ~ 60% and ~ 30% of GBM patients, respectively; however, therapies targeting EGFR have failed to improve disease outcome. EGFRvIII-mediated cross-activation of tyrosine kinase receptor, cMET, regulates GBM CSC maintenance and promote tumor recurrence. Here, we evaluated the efficacy of pan-EGFR inhibitor afatinib and Temozolomide (TMZ) combination on GBM in vitro and in vivo. Methods We analyzed the effect of afatinib and temozolomide (TMZ) combination on GBM cells U87MG and U251 engineered to express wild type (WT) EGFR, EGFRvIII or EGFRvIII dead kinase, CSCs isolated from U87 and U87EGFRvIII in vitro . The therapeutic utility of the drug combination was investigated on tumor growth and progression using intracranially injected U87EGFRvIII GBM xenografts. Results Afatinib and TMZ combination synergistically inhibited the proliferation, clonogenic survival, motility, invasion and induced senescence of GBM cells compared to monotherapy. Mechanistically, afatinib decreased U87EGFRvIII GBM cell proliferation and motility/invasion by inhibiting EGFRvIII/AKT, EGFRvIII/JAK2/STAT3, and focal adhesion kinase (FAK) signaling pathways respectively. Interestingly, afatinib specifically inhibited EGFRvIII-cMET crosstalk in CSCs, resulting in decreased expression of Nanog and Oct3/4, and in combination with TMZ significantly decreased their self-renewal property in vitro. More interestingly, afatinib and TMZ combination significantly decreased the xenograft growth and progression compared to single drug alone. Conclusion Our study demonstrated significant inhibition of GBM tumorigenicity, CSC maintenance in vitro , and delayed tumor growth and progression in vivo by combination of afatinib and TMZ. Our results warrant evaluation of this drug combination in EGFR and EGFRvIII amplified GBM patients. Electronic supplementary material The online version of this article (10.1186/s13046-019-1264-2) contains supplementary material, which is available to authorized users.

Hyperforin induces apoptosis through extrinsic/intrinsic pathways and inhibits EGFR/ERK/NF‐κB‐mediated anti‐apoptotic potential in glioblastoma

“…Aberrant EGFR expression mediates resistance to chemotherapy and radiotherapy through evoking anti‐apoptotic signaling 25,26 . Many preclinical and clinical studies indicated suppression of EGFR activation by EGFR inhibitors enhances anti‐glioblastoma efficacy of chemotherapy or radiotherapy 27,28 …”

Molecular implications of MUC5AC-CD44 axis in colorectal cancer progression and chemoresistance

“…Stem cell or non-stem cell populations were isolated by using ATP-binding cassette inhibitor (verapamil) and DNA staining dye (Hoechst 33342) [17]. Both parental and MUC5AC KO clones were seeded (approximately 1 × 10 6 cells) and treated with verapamil (75 μM).…”

EGFRvIII: An Oncogene with Ambiguous Role

“…Reports from in vitro studies conducted on EGFR vIII -expressing cell lines tend to be contradictory. Some results indicate EGFR vIII sensitivity, while the others demonstrate that EGFR vIII , in contrast to EGFR WT , appears to be relatively resistant to EGFR-TKIs [87]. By now, several TKI-involving clinical trials on glioblastoma were completed or terminated, however still without any significant patients' benefits [65,72,77,88,178,[184][185][186][187][188].…”