Antibody dependent cellular cytotoxicity-inducing anti-EGFR antibodies as effective therapeutic option for cutaneous melanoma resistant to BRAF inhibitors

Front Immunol. 2024 Mar 6:15:1336566. doi: 10.3389/fimmu.2024.1336566. eCollection 2024.

Abstract

Introduction: About 50% of cutaneous melanoma (CM) patients present activating BRAF mutations that can be effectively targeted by BRAF inhibitors (BRAFi). However, 20% of CM patients exhibit intrinsic drug resistance to BRAFi, while most of the others develop adaptive resistance over time. The mechanisms involved in BRAFi resistance are disparate and globally seem to rewire the cellular signaling profile by up-regulating different receptor tyrosine kinases (RTKs), such as the epidermal growth factor receptor (EGFR). RTKs inhibitors have not clearly demonstrated anti-tumor activity in BRAFi resistant models. To overcome this issue, we wondered whether the shared up-regulated RTK phenotype associated with BRAFi resistance could be exploited by using immune weapons as the antibody-dependent cell cytotoxicity (ADCC)-mediated effect of anti-RTKs antibodies, and kill tumor cells independently from the mechanistic roots.

Methods and results: By using an in vitro model of BRAFi resistance, we detected increased membrane expression of EGFR, both at mRNA and protein level in 4 out of 9 BRAFi-resistant (VR) CM cultures as compared to their parental sensitive cells. Increased EGFR phosphorylation and AKT activation were observed in the VR CM cultures. EGFR signaling appeared dispensable for maintaining resistance, since small molecule-, antibody- and CRISPR-targeting of EGFR did not restore sensitivity of VR cells to BRAFi. Importantly, immune-targeting of EGFR by the anti-EGFR antibody cetuximab efficiently and specifically killed EGFR-expressing VR CM cells, both in vitro and in humanized mouse models in vivo, triggering ADCC by healthy donors' and patients' peripheral blood cells.

Conclusion: Our data demonstrate the efficacy of immune targeting of RTKs expressed by CM relapsing on BRAFi, providing the proof-of-concept supporting the assessment of anti-RTK antibodies in combination therapies in this setting. This strategy might be expected to concomitantly trigger the crosstalk of adaptive immune response leading to a complementing T cell immune rejection of tumors.

Keywords: BRAF; antibody dependent cell cytotoxicity; cutaneous melanoma; drug resistance; receptor tyrosine kinases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibody-Dependent Cell Cytotoxicity
  • Cell Line, Tumor
  • Drug Resistance, Neoplasm / genetics
  • ErbB Receptors
  • Humans
  • Melanoma* / pathology
  • Mice
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use
  • Proto-Oncogene Proteins B-raf
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Skin Neoplasms* / pathology

Substances

  • Proto-Oncogene Proteins B-raf
  • Protein Kinase Inhibitors
  • Receptor Protein-Tyrosine Kinases
  • ErbB Receptors
  • BRAF protein, human
  • EGFR protein, human

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by Alleanza Contro il Cancro, Ministero della Salute (Ricerca Corrente and GR-2018-12366312 to EF), 5 × 1000 Institutional Grant from CRO Aviano, National Cancer Institute, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) (Intramural Grant to LS and MAP and Seed Grant to EM, BM and EF), AIRC Foundation for Cancer Research (Grant Number IG-23068 to AW). FS acknowledges funding from the National Health and Medical Research Council Ideas Grant APP2001396 and Philanthropic funding from Merchant Charitable Foundation (Grant number: 2019002447).