Improved Natural Killer cell activity and retained anti-tumor CD8+ T cell responses contribute to the induction of a pathological complete response in HER2-positive breast cancer patients undergoing neoadjuvant chemotherapy

Abstract

BackgroundLocally advanced HER2-overexpressing breast cancer (BC) patients achieve a high rate of pathological complete responses (pCR) after neoadjuvant chemotherapy (NC). The apparently unaltered immune proficiency of these patients together with the immune-modulating activities of NC drugs suggest a potential contribution of host immunity in mediating clinical responses. We thus performed an extensive immunomonitoring in locally advanced BC patients undergoing NC to identify immunological correlates of pCR induction.MethodsThe immune profile of 40 HER2-positive and 38 HER2-negative BC patients was characterized at diagnosis and throughout NC (Paclitaxel and Trastuzumab, or Docetaxel and Epirubicin, respectively). The percentages of circulating immune cell subsets including T and B lymphocytes, Natural Killer (NK) cells, regulatory T cells, T helper 17 lymphocytes, were quantified by multiparametric flow cytometry. NK cells functional activity was evaluated through the analysis of NF-kB nuclear translocation by Multispectral flow cytometry, and with the in vitro monitoring of Trastuzumab-mediated antibody-dependent cell cytotoxicity (ADCC). CD8+ T cell responses against six different tumor-associated antigens (TAA) were characterized by IFN-γ ELISPOT and IFN-γ/IL-2 DualSpot assays.ResultsAfter NC, HER2-positive patients showed a significant increase in the number of NK cells and regulatory T cells irrespective of the pathological response, whereas patients undergoing a pCR disclosed higher percentages of T helper 17 cells. Notably, a significant increase in the number of activated NK cells was observed only in HER2-positive patients achieving a pCR. Characterization of anti-tumor T cell responses highlighted sustained levels of CD8+ T cells specific for survivin and mammaglobin-A throughout NC in patients undergoing a pCR in both arms. Moreover, HER2-positive patients achieving a pCR were characterized by a multi-epitopic and polyfunctional anti-tumor T cell response, markedly reduced in case of partial response.ConclusionsThese results indicate that maintenance of functional T cell responses against selected antigens and improvement of NK cell proficiency during NC are probably critical requirements for pCR induction, especially in HER2-positive BC patients.Trail registration: Trial registration number: NCT02307227, registered on ClinicalTrials.gov (http://www.clinicaltrials.gov, November 26, 2014).Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-015-0567-0) contains supplementary material, which is available to authorized users.

Circulating Tumor Cells (CTC) Are Associated with Defects in Adaptive Immunity in Patients with Inflammatory Breast Cancer

“…Twenty-four patients included in the study were HER2 positive, and 9 (37.5%) of them were pretreated with trastuzumab-based chemotherapy. Trastuzumab is known to activate both the innate and the adaptive immune systems as well as to be capable of inducing long-lasting immune responses by reducing circulating T regulatory cells 35 , 36 . However, there was not a significant difference in any of the analyzed T-cell subsets in patients with mIBC based on previous treatment, except ALC, that was significantly higher in patients with prior to trastuzumab treatment in contrast to patients who were pretreated with chemotherapy without trastuzumab (p = 0.04).…”

GRP78 expression in peripheral blood mononuclear cells is a new predictive marker for the benefit of taxanes in breast cancer neoadjuvant treatment

“…We found significantly higher concentrations of the inflammatory cytokine IFNγ in the sera of patients who achieved pCR only at the end of the taxane phase: IFNγ levels were correlated with the presence of GRP78-positive clones in PBMC subpopulations in these patients. Previous studies described antitumor CD8(+) T cell responses with increase in IFNγ levels in pCR Her2-positive breast cancer patients undergoing neoadjuvant chemotherapy [41]. Accumulating data show that UPR activation plays a role in a number of physiological events associated with immune cells and with modulation of inflammatory signaling pathways, resulting in cytokine production [42,43].…”

<p>Combination Strategies of Checkpoint Immunotherapy in Metastatic Breast Cancer</p>

“…42 Trastuzumab has been reported to modulate immune activity, mediate antibody-dependent cellular cytotoxicity (ADCC) and promote T-cell response. 43 Clinically, data from the PANACEA study (NCT02129556) demonstrated the durable clinical benefit of pembrolizumab plus trastuzumab in patients with PD-L1-positive, trastuzumab-resistant, advanced, HER-2-positive breast cancer. In this single-arm, multicenter trial, 6 patients were enrolled in phase 1b and 52 patients in Phase 2.…”