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

• Published in: Breast cancer research and treatment 2011-11, Vol.130 (2), p.465-475
• Main Authors: Roberti, M. P., Barrio, M. M., Bravo, A. I., Rocca, Y. S., Arriaga, J. M., Bianchini, M., Mordoh, J., Levy, E. M.
• Format: Article
• Language: English
• Subjects: Analysis; Antibodies, Monoclonal - pharmacology; Antibodies, Monoclonal, Humanized; Antineoplastic Agents - pharmacology; Apoptosis - drug effects; Base Sequence; Biological and medical sciences; Breast cancer; Breast Neoplasms; Cancer research; Cancer therapies; Cell Line, Tumor; Cell Proliferation - drug effects; Cetuximab; Coculture Techniques; Cytotoxicity; DNA Mutational Analysis; Estrogen; Fc receptors; Female; Genotype & phenotype; GPI-Linked Proteins - genetics; GPI-Linked Proteins - metabolism; Gynecology. Andrology. Obstetrics; Humans; Interferon-gamma - metabolism; Interferon-gamma - secretion; Interleukin-15 - pharmacology; Interleukin-15 - physiology; Interleukin-2 - pharmacology; Interleukin-2 - physiology; Killer Cells, Natural - drug effects; Killer Cells, Natural - metabolism; Mammary gland diseases; Medical sciences; Medicine; Medicine & Public Health; Monoclonal antibodies; NK Cell Lectin-Like Receptor Subfamily K - genetics; NK Cell Lectin-Like Receptor Subfamily K - metabolism; Oncology; Point Mutation; Preclinical Study; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins p21(ras); ras Proteins - genetics; Receptor, Epidermal Growth Factor - metabolism; Receptor, ErbB-2 - metabolism; Receptors, Estrogen - metabolism; Receptors, IgG - genetics; Receptors, IgG - metabolism; Receptors, Progesterone - metabolism; Tumors; Up-Regulation - drug effects
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-011-1360-2

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 IIB-BR-G MT. Furthermore, IL-15 pretreatment increased the ADCC up to 71 ± 3% in IIB-BR-G and 79 ± 3.5% in IIB-BR-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. EGFR-expressing 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-γ, and paralleling the up-regulation of activating receptors.