A. Ali Zirakzadeh

Multiplex B Cell Characterization in Blood, Lymph Nodes, and Tumors from Patients with Malignancies

B lymphocytes contribute to immune surveillance, by tumor-specific Abs and Ag presentation to T lymphocytes, but are insufficiently studied in humans. In this article, we report a flow cytometric investigation of B lymphocyte subpopulations in blood, lymph nodes (LNs), and malignant tissues from 20 patients operated on because of advanced solid tumors. The CD19+ compartment in peripheral blood was essentially unaltered in patients, as compared with healthy control subjects. In metastatic LNs, signs of B lymphocyte activation were observed, as evidenced by increased proportions of plasmablasts and CD86-expressing cells. In tumor-infiltrating B lymphocytes (TIL-B), both switched memory cells and plasmablasts were expanded, as compared with nonmalignant epithelium. Moreover, pronounced skewing of Igλ/Igκ ratio was evident among TIL-Bs. By spectratype analysis on IgH, we confirmed a monoclonal expansion of the Vh7 family in TIL-B, also present in a tumor-associated LN. Sequencing the clonally expanded Vh7 revealed signs of somatic hypermutation. In conclusion, B lymphocytes in cancer patients exhibit signs of activation in tumor-associated tissues, likely induced by recognition of tumor Ags. Increased numbers of switched memory cells and plasmablasts in combination with clonal expansion and signs of somatic hypermutation suggest a CD4+ T lymphocyte–dependent antitumoral response, which may be exploited for immunotherapy.

The effects of chemotherapeutic drugs on human monocyte-derived dendritic cell differentiation and antigen presentation

Recent studies indicate that chemotherapeutic agents may increase the anti‐tumoral immune response. Based on the pivotal role of dendritic cells (DCs) in host tumour‐specific immune responses, we investigated the effect of commonly used chemotherapeutic drugs dexamethasone, doxorubicin, cisplatin and irinotecan and glucocorticoids on monocyte‐derived DCs (moDCs). Dexamethasone displayed the strongest inhibitory effect on DC differentiation. The effect of cisplatin and irinotecan was moderate, while only weak effects were noticed for doxorubicin. Surprisingly, when the functional consequence of chemotherapy‐treated CD14+ monocytes and their capacity to activate CD4+ T responders cells were investigated, cisplatin‐treated monocytes gave rise to increased T cell proliferation. However, dexamethasone, doxorubicin and irinotecan‐pretreated monocytes did not stimulate any increased T cell proliferation. Further investigation of this observation revealed that cisplatin treatment during DC differentiation up‐regulated significantly the interferon (IFN)‐β transcript. By contrast, no effect was evident on the expression of interleukin (IL)‐1β, tumour necrosis factor (TNF)‐α, IL‐6 or IFN‐α transcripts. Blocking IFN‐β attenuated the cisplatin‐enhanced T cell proliferation significantly. In conclusion, cisplatin treatment enhanced the immune stimulatory ability of human monocytes, a mechanism mediated mainly by the increased production of IFN‐β.

The many flavors of tumor-associated B cells

Little is known on the role of distinct B-cell subtypes in human malignancies. We have recently performed a multiplex characterization of B cells in patient-derived tumor-associated tissues, documenting the activation and antigen-driven differentiation of B cells in metastatic lymph nodes and neoplastic lesions. Here we discuss the role of B lymphocytes as antigen-presenting cells and catalysts of T cell-based immunotherapies in view of these findings.

Doxorubicin enhances the capacity of B cells to activate T cells in urothelial urinary bladder cancer

Cancer is currently treated by a combination of therapies, including chemotherapy which is believed to suppress the immune system. Combination of immunotherapy and chemotherapy correlates with improved survival but needs careful planning in order to achieve a synergistic effect. In this study, we have demonstrated that doxorubicin treatment of B cells resulted in increased expression of CD86 and concordantly increased CD4+ T cell activation in the presence of superantigen, an effect that was inhibited by the addition of a CD86 blocking antibody. Furthermore, doxorubicin resulted in decreased expression of the anti-inflammatory cytokines IL-10 and TNF-α. Finally, B cells from urinary bladder cancer patients, treated with a neoadjuvant regiment containing doxorubicin, displayed increased CD86-expression. We conclude that doxorubicin induces CD86 expression on B cells and hence enhances their antigen-presenting ability in vitro, a finding verified in patients. Development of tailored time and dose schedules may increase the effectiveness of combining chemotherapy and immunotherapy.

Urothelial bladder cancer may suppress perforin expression in CD8+ T cells by an ICAM-1/TGFβ2 mediated pathway

The immune system plays a significant role in urothelial bladder cancer (UBC) progression, with CD8+ T cells being capable to directly kill tumor cells using perforin and granzymes. However, tumors avoid immune recognition by escape mechanisms. In this study, we aim to demonstrate tumor immune escape mechanisms that suppress CD8+ T cells cytotoxicity. 42 patients diagnosed with UBC were recruited. CD8+ T cells from peripheral blood (PB), sentinel nodes (SN), and tumor were analyzed in steady state and in vitro-stimulated conditions by flow cytometry, RT-qPCR, and ELISA. Mass spectrometry (MS) was used for identification of proteins from UBC cell line culture supernatants. Perforin was surprisingly found to be low in CD8+ T cells from SN, marked by 1.8-fold decrease of PRF1 expression, with maintained expression of granzyme B. The majority of perforin-deficient CD8+ T cells are effector memory T (TEM) cells with exhausted Tc2 cell phenotype, judged by the presence of PD-1 and GATA-3. Consequently, perforin-deficient CD8+ T cells from SN are low in T-bet expression. Supernatant from muscle invasive UBC induces perforin deficiency, a mechanism identified by MS where ICAM-1 and TGFβ2 signaling were causatively validated to decrease perforin expression in vitro. Thus, we demonstrate a novel tumor escape suppressing perforin expression in CD8+ T cells mediated by ICAM-1 and TGFβ2, which can be targeted in combination for cancer immunotherapy.

Neoadjuvant Chemotherapy Reinforces Antitumour T cell Response in Urothelial Urinary Bladder Cancer

Evidence indicates that neoadjuvant chemotherapy (NAC) may promote antitumour immune responses by activating T cells. The tumour-draining sentinel node (SN) is a key site to study tumour-specific T cell activation, being the primary immunological barrier against the tumour. In this prospective study, we set out to elucidate the effects of NAC on T cell subsets in the SNs of patients with muscle-invasive urothelial bladder cancer. We found that CD8+ effector T (Teff) cell exhaustion was reduced after NAC treatment, while cytotoxicity was increased. Additionally, in complete responders (CR patients), these cells were functionally committed effectors, as displayed by epigenetic analysis. In CD4+ Teffs, NAC treatment was associated with increased clonal expansion of tumour-specific SN-derived cells, as demonstrated by a specific cell reactivity assay. In contrast, we observed an attenuating effect of NAC on regulatory T cells (Tregs) with a dose-dependent decrease in Treg frequency and reduced effector molecule expression in the remaining Tregs. In addition, multicolour flow cytometry analysis revealed that CR patients had higher Teff to activated Treg ratio, promoting antitumoural T cell activation. These results suggest that NAC reinforces the antitumour immune response by activating the effector arm of the T cell compartment and diminishing the influence of suppressive Tregs. PATIENT SUMMARY: In this report, we analysed the effect of chemotherapy on immune cell subsets of 40 patients with advanced bladder cancer. We found that chemotherapy has a positive effect on immune effector T cells, whereas an opposite, diminishing effect was observed for immune-suppressive regulatory T cells. We conclude that chemotherapy reinforces the antitumour immune response in bladder cancer patients.

Urinary Bladder Cancer Tregs Suppress MMP2 and Potentially Regulate Invasiveness

Tregs localized to the invasive front of human bladder tumors inhibited the expression of MMP2, an enzyme that cleaves extracellular matrix and promotes metastasis. Therefore, caution should be exercised in the clinical targeting of Tregs in inflammation-driven cancers. Regulatory T cells (Treg) have long been considered one-sided suppressors of antitumor immune responses and hence associated with poor patient outcome in cancer. However, evidence is mounting of a paradoxical positive prognostic effect of Tregs on certain malignancies, including urinary bladder cancer (UBC). This discrepancy has partly been attributed to the shear misidentification of Tregs, but also to the inflammatory profile of the tumor. Our aim was to determine whether tumor-infiltrating Forkhead box P3+ (FOXP3+) cells confer a stable Treg phenotype and to investigate putative beneficial Treg functions, focusing on tumor-promoting inflammatory pathways in UBC. Patients (n = 52) with suspected UBC were prospectively included. We show, by using a broad range of analytical approaches, that tumor-infiltrating CD4+FOXP3+ T cells in UBC phenotypically, functionally, and epigenetically represent a true Treg population. At the invasive front of UBC tumors, we found an inverse relationship between Treg frequency and expression of matrix metalloproteinase 2 (MMP2), a key proinvasive factor induced by tumor-promoting inflammation. Correspondingly, a significant, dose-dependent Treg-mediated downregulation of MMP2 protein and mRNA expression was observed in both macrophages and UBC cells. Also, we found that Treg frequency specifically at the invasive front positively correlated with survival. Thus, we identify Treg-mediated suppression of MMP2 in the tumor microenvironment as a mechanism explaining the paradoxical positive prognostic impact of tumor-infiltrating Tregs in UBC. Cancer Immunol Res; 6(5); 528–38. ©2018 AACR.

Individual immunoproteomics identifies il-16 processing in tregs as a factor in bladder cancer tumour immunity

Introduction: The incidence of renal cell carcinoma (RCC), accounting for more than 90% of all renal malignances, has increased globally during recent decades. Obesity is a well-established risk fa ...No difference in risk of cardiovascular disease in men with prostate cancer treated with GnRH agonists or orchiectomy : semi-ecologic, nationwide, population-based studyExosomes in urine retain a malignant protein profile after primary tumour ablation in patients with invasive urinary bladder cancerSentinel node detection in muscle invasive urothelial bladder cancer is feasible after neoadjuvant chemotherapy in all pT-stagesSignificantly more downstaging in patients recieving preoperative (neoadjuvant and induction) chemotherapy prior to cystectomy for muscle-invasive bladder cancerIntroduction: The role of inflammation in prostate cancer has been widely discussed [1]. Exploring the association between immunological or inflammatory conditions, that reflect immune response pro ...Individual immunoproteomics identifies il-16 processing in tregs as a factor in bladder cancer tumour immunity

B cells in tumor draining lymph nodes act as efficient antigen presenting cells in cancer patients

Overall Survival of patients with muscle invasive urothelial bladder cancer MIBC remains around 50% (5 years), albeit some improvements by combining neoadjuvant chemotherapy with radical surgery. Our previous work has demonstrated that in vitro expansions of sentinel node-acquired autologous tumor specific CD4+ T cells are promising for adoptive immunotherapy [1]. In order for naive T helper cells to become activated, they need effective APCs, presenting tumor antigens. In another study, we observed that B cells in cancer patients were tumor antigen experienced and from their phenotypes we suggested a CD4+ T cell dependent anti-tumoral response [2]. In this study, we report a flow cytometric investigation of tumor draining lymph node (sentinel node) derived B cell activation by autologous tumor extract in patients with MIBC.

The effect of chemotherapeutic drugs on human B lymphocytes

Cancer is currently treated by a combination of therapies, including chemotherapy. As a side effect, chemotherapy is believed to suppress the host immune system. Combination of immunotherapy and chemotherapy has been reported to be correlated with improvement of survival. However this combination needs careful planning in order to achieve a synergistic effect. In this study we have performed a flow cytometry analysis of lymphoblast transformation to investigate the effects of three conventional chemotherapeutic drugs, cisplatin, doxorubicin and irinotecan on human B cells and their role as APC.