Radiofrequency ablation for the treatment of HCC – Maybe much more than simple tumor destruction?

COMMENTARY ONRadiofrequency thermal ablation for hepatocellular carcinoma stimulates autologous NK-cell response. Zerbini A, Pilli M, Laccabue D, Pelosi G, Molinari A, Negri E, Cerioni S, Fagnoni F, Soliani P, Ferrari C, Missale G. Gastroenterology, 2010 May;138(5):1931–1942. Eup 2010 Jan 11. Copyright 2010. Abstract reprinted with permission from Elsevier Inc.www.ncbi.nlm.gov/pubmed/20060829Abstract: Background & AimsRadiofrequency thermal ablation (RFA) is a minimally invasive technique used as standard local therapy of hepatocellular carcinoma and second-line treatment for metastatic liver tumors. Studies in preclinical models and in patients have shown that thermal destruction of tumor tissue can enhance anti-tumor cellular responses, but our knowledge of its impact on natural killer (NK) cells is still very limited.MethodsThirty-seven patients undergoing RFA for hepatocellular carcinoma were studied for peripheral blood lymphocytes counts followed by phenotypic and functional characterization of NK-cell population.ResultsPeripheral blood lymphocytes kinetics revealed an increased frequency and absolute number of NK-cells expressing higher levels of activatory along with reduced levels of inhibitory NK receptors, and increased functional NK-cell activity. A prevalent expansion of the CD3(−)CD56(dim) NK subset was observed compared to the CD3(−)CD56(bright) counterpart. Interferon-gamma production, anti-K562 cell-cytotoxicity, and antibody-dependent cell-cytotoxicity, appeared consistently increased in terms of both absolute activity and killing efficiency at 4weeks after RFA, as compared to baseline. Interestingly, when recurrence-free survival was assessed in two groups of patients separated according to higher vs lower enhancement of cytotoxicity and/or interferon-gamma production, a significant difference was observed, thus suggesting a potential predictive role of NK functional assays on efficacy of RFA.ConclusionsRFA can lead to stimulation of NK-cells with a more differentiated and proactivatory phenotypic profile with general increase of functional activities. This observation may be relevant for development of adjuvant immunotherapeutic strategies aimed at enhancing NK-cell responses against primary and metastatic liver tumors. Copyright 2010 AGA Institute

Tumour-derived GM-CSF promotes granulocyte immunosuppression in mesothelioma patients

Abstract Purpose: The cross-talk between tumor cells, myeloid cells, and T cells can play a critical role in tumor pathogenesis and response to immunotherapies. Although the etiology of mesothelioma is well understood, the impact of mesothelioma tumor cells on the surrounding immune microenvironment is less well studied. In this study, the effect of the mesothelioma tumor microenvironment on circulating and infiltrating granulocytes and T cells is investigated. Experimental Design: Tumor tissues and peripheral blood from mesothelioma patients were evaluated for presence of granulocytes, which were then tested for their T-cell suppression potential. Different cocultures of granulocytes and/or mesothelioma tumor cells and/or T cells were set up to identify the mechanism of T-cell inhibition. Results: Analysis of human tumors showed that the mesothelioma microenvironment is enriched in infiltrating granulocytes, which inhibit T-cell proliferation and activation. Characterization of the whole blood at diagnosis identified similar, circulating, immunosuppressive CD11b+CD15+HLADR− granulocytes at increased frequency compared with healthy controls. Culture of healthy-donor granulocytes with human mesothelioma cells showed that GM-CSF upregulates NOX2 expression and the release of reactive oxygen species (ROS) from granulocytes, resulting in T-cell suppression. Immunohistochemistry and transcriptomic analysis revealed that a majority of mesothelioma tumors express GM-CSF and that higher GM-CSF expression correlated with clinical progression. Blockade of GM-CSF with neutralizing antibody, or ROS inhibition, restored T-cell proliferation, suggesting that targeting of GM-CSF could be of therapeutic benefit in these patients. Conclusions: Our study presents the mechanism behind the cross-talk between mesothelioma tumors and the immune microenvironment and indicates that targeting GM-CSF could be a novel treatment strategy to augment immunotherapy in patients with mesothelioma. Clin Cancer Res; 24(12); 2859–72. ©2018 AACR.</jats:p

Peptide-β2-microglobulin-major histocompatibility complex expressing cells are potent antigen-presenting cells that can generate specific T cells

Adoptive T-cell therapy represents a promising therapeutic approach for the treatment of cancer. Successful adoptive immunotherapy depends on the ex vivo priming and expansion of antigen-specific T cells. However, the in vitro generation of adequate numbers of functional antigen-specific T cell remains a major obstacle. It is important to develop efficient and reproducible methods to generate high numbers of antigen-specific T cells for adoptive T-cell transfer. We have developed a new artificial antigen-presenting cell (aAPC) by transfection of major histocompatibility (MHC) class I negative Daudi cells with a peptide-β2-microglobulin–MHC fusion construct (single-chain aAPC) ensuring presentation of the peptide–MHC complex of interest. Using this artificial antigen-presenting cell, we could generate up to 9·2 × 108 antigen-specific cytotoxic CD8+ T cells from 10 ml blood. In vitro generated T cells lysed endogenously presented antigens. Direct comparison of the single-chain aAPC with autologous monocyte-derived dendritic cells demonstrated that these cells were equally efficient in stimulation of T cells. Finally, we were able to generate antigen-specific T cell lines from perpheral blood mononuclear cells of patients receiving cytotoxic chemotherapy. The use of single-chain aAPC represent a promising option for the generation of antigen-specific CD8+ T cells, which could be used for adoptive T-cell therapy

Tumour-Associated Transcripts and EGFR Deletion Variants in Colorectal Cancer in Primary Tumour, Metastases and Circulating Tumour Cells

The clinical relevance of circulating tumour cells (CTC) in peripheral blood of patients with colorectal cancer (CRC) has been described as an independent prognostic factor useful to monitor drug effects and clinical status. The aim of the present study was to compare the epidermal growth factor receptor (EGFR) status of primary tumour, related metastases and CTC of patients with CRC. Therefore, in addition to EGFR, the tumour-associated transcripts gastrointestinal tumour-associated antigen 733-2 (GA733-2) and carcinoembryonic antigen (CEA) were analyzed in a multiplex RT-PCR to characterize CTC. 55% patients were positive for CTC. EGFR expression was detected in 18% of these patients. EGFR was expressed more frequently in metastatic and primary tumour tissues as revealed by immunohistochemistry. Besides, detailed expression profiling of EGFR variants in various colorectal and glioma cell lines has been performed to generate positive controls, resulting in the discovery of two new transcript deletion variations (cEX12_15del, cEX12_14del) located on the extracellular domain of the EGFR

An immunodominant MHC class II-restricted tumor antigen is conformation dependent and binds to the endoplasmic reticulum chaperone, calreticulin

There is accumulating evidence that CD4+ T cell responses are important in antitumor immunity. Accordingly, we generated CD4+ T cells against the murine CT26 colon cancer. Three of three independent CT26-specific CD4+ hybridomas were found to recognize the high m.w. precursor of the env gene product gp90. The CD4+ response was completely tumor specific in that the same glycoprotein expressed by other tumors was not recognized by the CT26-specific hybridomas. The recognition of gp90 by the hybridomas was strictly dependent on the conformation of gp90. Different procedures that disrupted the conformation of the glycoprotein, such as disulfide bond reduction and thermal denaturation, completely abrogated recognition of gp90 by all three hybridomas. In CT26 cells, but not in other tumor cells tested, a large proportion of gp90 was retained in the endoplasmic reticulum, mostly bound to the endoplasmic reticulum chaperone, calreticulin. Although calreticulin was not essential for the stimulation of the gp90-specific hybridomas, most of the antigenic form of gp90 was bound to it. The antigenicity of gp90 correlated well with calreticulin binding, reflecting the fact that specificity of binding of calreticulin to its substrate required posttranslational modifications that were also necessary for the generation of this tumor-specific CD4+ epitope