IL-15 and IL-2 increase Cetuximab-mediated cellular cytotoxicity against triple negative breast cancer cell lines expressing EGFR

  • M. P. Roberti
  • , M. M. Barrio
  • , A. I. Bravo
  • , Y. S. Rocca
  • , J. M. Arriaga
  • , M. Bianchini
  • , J. Mordoh
  • , E. M. Levy

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

Triple negative breast cancer (TNBC) patients are not likely to benefit from anti-estrogen or anti-HER2 therapy and this phenotype is associated with a more aggressive clinical course and worse clinical outcome. Taking into account the limited treatment possibilities in TNBC, the aim of the present work was to study a potential therapy based on Cetuximab-mediated immune activity by natural killer (NK) cells. We performed in vitro studies on human breast cancer (BC) cell lines, IIB-BR-G, and the in vivo metastatic variant IIB-BR-G MT. The immunohistochemical analysis showed a TNBC phenotype with high but different levels of EGFR expression on each cell line, measured by flow cytometry. DNA sequencing showed that both cell lines have a mutated K-RAS status, 38 G>A at codon 13. Consequently, Cetuximab did not inhibit cellular proliferation or induce apoptosis. We investigated if Cetuximab could trigger immune mechanisms, and we determined that both cell lines treated with 1 μg/ml Cetuximab were susceptible to antibody dependent cellular cytotoxicity (ADCC), mediated by peripheral blood mononuclear cells (PBMC). At 50:1 effector:target ratio, lytic activity was 34 ± 2% against IIB-BR-G and 27 ± 6% against IIB-BR-G MT cells. PBMC pretreatment with IL-2 allowed reaching 65 ± 3% of Cetuximab-mediated ADCC against IIB-BR-G and 63 ± 6.5% against IIBBR- G MT. Furthermore, IL-15 pretreatment increased the ADCC up to 71 ± 3% in IIB-BR-G and 79 ± 3.5% in IIBBR- G MT. We suggest that NK cells are the effectors present in PBMC since they were able to induce ADCC at lower effector:target ratios. Besides, IL-2- and mainly IL- 15-induced upregulation of NK activating receptors CD16 and NKG2D and enhanced IFN-γ production. EGFRexpressing TNBC could be killed by Cetuximab-mediated ADCC at clinically achievable concentrations. IL-15 could advantageously replace IL-2 in most of its immunologic activities, stimulating the ability to produce IFN-c, and paralleling the up-regulation of activating receptors.

Original languageEnglish
Pages (from-to)465-475
Number of pages11
JournalBreast Cancer Research and Treatment
Volume130
Issue number2
DOIs
StatePublished - Nov 2011
Externally publishedYes

Keywords

  • Cetuximab-mediated cytotoxicity
  • IL-2 and IL-15
  • K-RAS status
  • Triple negative breast cancer

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