Published in:
01-12-2016 | Research Paper
CD4+FOXP3+ T regulatory cells decrease and CD3+CD8+ T cells recruitment in TILs from melanoma metastases after electrochemotherapy
Authors:
P. Di Gennaro, G. Gerlini, C. Urso, S. Sestini, P. Brandani, N. Pimpinelli, L. Borgognoni
Published in:
Clinical & Experimental Metastasis
|
Issue 8/2016
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Abstract
Electrochemotherapy (ECT) represents an effective local treatment for skin unresectable melanoma metastases with high overall objective response rate. ECT is based on the combination of anti-neoplastic drugs administration and cancer cells electroporation. Whether ECT can also activate the immune system is a matter of debate, however a significant recruitment of dendritic cells in melanoma treated metastases has been described. Herein we investigated immediate and late effects of ECT treatment on T cell subsets in ECT-treated lesions by fluorescent immunohistochemistry. Biopsies from melanoma patients (n = 10) were taken before ECT (t0), at d1 and d14 from treatment. At t0, CD3+CD4+ T cells were the most represented T cells, well detected in the perilesional dermis, particularly at tumour margin, while CD3+CD8+ T cells were less represented. CD4+FOXP3+ T regulatory (Treg) cells were present in the perilesional dermis and within the lesion. ECT induced a significant decrease of CD4+FOXP3+ Treg cells percentage in the perilesional dermis, observed at d1 and at d14 (p < 0.001). CD3+CD8+ T cells frequency significantly increased at d14 from treatment in the perilesional dermis (p < 0.001). Furthermore calreticulin translocation to the plasma membrane, a hallmark of immunogenic cell death, was observed in metastatic cells after ECT. The data reported here confirm that ECT induces a local response, with a lymphoid infiltrate characterized by CD4+FOXP3+ Treg cells decrease and CD3+CD8+ T cells recruitment in the treated lesions. These results might contribute to design novel combinational therapeutic approaches with ECT and immunotherapy in order to generate a systemic long-lasting anti-melanoma immunity.