Stephen R. Mattarollo

Contribution of IL-17–producing γδ T cells to the efficacy of anticancer chemotherapy

IL-17 production by γδ T cells is required for tumor cell infiltration by IFN-γ–producing CD8+ T cells and inhibition of tumor growth in response to anthracyclines.

Pivotal Role of Innate and Adaptive Immunity in Anthracycline Chemotherapy of Established Tumors

We show, in a series of established experimental breast adenocarcinomas and fibrosarcomas induced by carcinogen de novo in mice, that the therapeutic efficacy of doxorubicin treatment is dependent on CD8 T cells and IFN-γ production. Doxorubicin treatment enhances tumor antigen-specific proliferation of CD8 T cells in tumor-draining lymph nodes and promotes tumor infiltration of activated, IFN-γ-producing CD8 T cells. Optimal doxorubicin treatment outcome also requires both interleukin (IL)-1β and IL-17 cytokines, as blockade of IL-1β/IL-1R or IL-17A/IL-17Rα signaling abrogated the therapeutic effect. IL-23p19 had no observed role. The presence of γδ T cells, but not Jα18(+) natural killer T cells, at the time of doxorubicin treatment was also important. In tumor samples taken from breast cancer patients prior to treatment with anthracycline chemotherapy, a correlation between CD8α, CD8β, and IFN-γ gene expression levels and clinical response was observed, supporting their role in the therapeutic efficacy of anthracyclines in humans. Overall, these data strongly support the pivotal contribution of both innate and adaptive immunity in treatment outcomes of anthracycline chemotherapy.

Molecular and Translational Classifications of DAMPs in Immunogenic Cell Death

The immunogenicity of malignant cells has recently been acknowledged as a critical determinant of efficacy in cancer therapy. Thus, besides developing direct immunostimulatory regimens, including dendritic cell-based vaccines, checkpoint-blocking therapies, and adoptive T-cell transfer, researchers have started to focus on the overall immunobiology of neoplastic cells. It is now clear that cancer cells can succumb to some anticancer therapies by undergoing a peculiar form of cell death that is characterized by an increased immunogenic potential, owing to the emission of the so-called “damage-associated molecular patterns” (DAMPs). The emission of DAMPs and other immunostimulatory factors by cells succumbing to immunogenic cell death (ICD) favors the establishment of a productive interface with the immune system. This results in the elicitation of tumor-targeting immune responses associated with the elimination of residual, treatment-resistant cancer cells, as well as with the establishment of immunological memory. Although ICD has been characterized with increased precision since its discovery, several questions remain to be addressed. Here, we summarize and tabulate the main molecular, immunological, preclinical, and clinical aspects of ICD, in an attempt to capture the essence of this phenomenon, and identify future challenges for this rapidly expanding field of investigation.

Clinical evaluation of autologous gamma delta T cell-based immunotherapy for metastatic solid tumours.

Background:Adoptive transfer of ex vivo expanded autologous Vγ9Vδ2 T cells may be of therapeutic benefit for cancer because of their potent direct cytotoxicity towards tumour cells, synergistic cytotoxicity when combined with aminobisphosphonates and enhancement of antibody-dependent cell-mediated cytotoxicity.Methods:To determine the feasibility and clinical safety of therapy with ex vivo expanded, activated Vγ9Vδ2 T cells in combination with zoledronate, we enrolled 18 subjects with advanced solid tumours into a phase I clinical study. Administered indium111-oxine-labelled Vγ9Vδ2 T cells were tracked in a cohort of patients.Results:Administered Vγ9Vδ2 T cells had an activated effector memory phenotype, expressed chemokine receptors predictive of homing to peripheral tissues and were cytotoxic in vitro against tumour targets. Adoptively transferred Vγ9Vδ2 T cells trafficked predominantly to the lungs, liver and spleen and, in some patients, to metastatic tumour sites outside these organs. No dose-limiting toxicity was observed, but most patients progressed on study therapy. However, three patients administered Vγ9Vδ2 T cells while continuing previously ineffective therapy had disease responses, suggesting an additive effect.Conclusion:Therapy with aminobisphosphonate-activated Vγ9Vδ2 T cells is feasible and well tolerated, but therapeutic benefits appear only likely when used in combination with other therapies.

Prevention and Treatment of Papillomavirus-Related Cancers Through Immunization

Cervical and other anogenital cancers are initiated by infection with one of a small group of human papillomaviruses (HPV). Virus-like particle-based vaccines have recently been developed to prevent infection with two cancer-associated HPV genotypes (HPV16, HPV18) and have been ∼95% effective at preventing HPV-associated disease caused by these genotypes in virus-naive subjects. Although immunization induces virus-neutralizing antibody sufficient to prevent infection, persistence of antibody as measured by current assays does not appear necessary to maintain protection over time. Investigators have not identified a reliable surrogate immunological marker of protection against disease following immunization. The prophylactic vaccines are not therapeutic for existing infection. Trials of HPV-specific immunotherapy have shown some efficacy for existing disease, although animal modeling suggests that a combination of immunization and local enhancement of innate immunity may be necessary for optimal therapeutic outcome. HPV prophylactic vaccines are the first vaccines designed to prevent a human cancer and are the practical outcome of a global collaborative effort between basic and applied scientists, clinicians, and industry.

Vγ9Vδ2 T cell cytotoxicity against tumor cells is enhanced by monoclonal antibody drugs—Rituximab and trastuzumab

Vγ9Vδ2 T cells exert potent cytotoxicity toward various tumor cells and adoptive transfer of Vγ9Vδ2 T cells is an attractive proposition for cell based immunotherapy. Vγ9Vδ2 T cells expanded in the presence of Zoledronate and IL‐2 express CD16 (FcγRIII), which raises the possibility that Vγ9Vδ2 T cells could be used in conjunction with tumor targeting monoclonal antibody drugs to increase antitumor cytotoxicity by antibody dependent cellular cytotoxicity (ADCC). Cytotoxic activity against CD20‐positive B lineage lymphoma or chronic lymphocytic leukemia (CLL) and HER2‐positive breast cancer cells was assessed in the presence of rituximab and trastuzumab, respectively. Cytotoxicity of Vγ9Vδ2 T cells against CD20‐positive targets was higher when used in combination with rituximab. Similarly, Vγ9Vδ2 T cells used in combination with trastuzumab resulted in greater cytotoxicity against HER2‐positive cells in comparison with either agent alone and this effect was restricted to the CD16+Vγ9Vδ2 T cell population. Our results show that CD16+Vγ9Vδ2 T cells recognize monoclonal antibody coated tumor cells via CD16 and exert ADCC similar to that observed with NK cells, even when target cells are relatively resistant to monoclonal antibodies or Vγ9Vδ2 T cells alone. Combination therapy involving ex vivo expanded CD16+Vγ9Vδ2 T cells and monoclonal antibodies may enhance the clinical outcomes for patients treated with monoclonal antibody therapy.

An Intact Immune System Is Required for the Anticancer Activities of Histone Deacetylase Inhibitors

Cell-intrinsic effects such as induction of apoptosis and/or inhibition of cell proliferation have been proposed as the major antitumor responses to histone deacetylase inhibitors (HDACi). These compounds can also mediate immune-modulatory effects that may contribute to their anticancer effects. However, HDACi can also induce anti-inflammatory, and potentially immunosuppressive, outcomes. We therefore sought to clarify the role of the immune system in mediating the efficacy of HDACi in a physiologic setting, using preclinical, syngeneic murine models of hematologic malignancies and solid tumors. We showed an intact immune system was required for the robust anticancer effects of the HDACi vorinostat and panobinostat against a colon adenocarcinoma and two aggressive models of leukemia/lymphoma. Importantly, although HDACi-treated immunocompromised mice bearing established lymphoma succumbed to disease significantly earlier than tumor bearing, HDACi-treated wild-type (WT) mice, treatment with the conventional chemotherapeutic etoposide equivalently enhanced the survival of both strains. IFN-γ and tumor cell signaling through IFN-γR were particularly important for the anticancer effects of HDACi, and vorinostat and IFN-γ acted in concert to enhance the immunogenicity of tumor cells. Furthermore, we show that a combination of vorinostat with α-galactosylceramide (α-GalCer), an IFN-γ-inducing agent, was significantly more potent against established lymphoma than vorinostat treatment alone. Intriguingly, B cells, but not natural killer cells or CD8(+) T cells, were implicated as effectors of the vorinostat antitumor immune response. Together, our data suggest HDACi are immunostimulatory during cancer treatment and that combinatorial therapeutic regimes with immunotherapies should be considered in the clinic.

CCL2/CCR2-Dependent Recruitment of Functional Antigen-Presenting Cells into Tumors upon Chemotherapy

The therapeutic efficacy of anthracyclines relies, at least partially, on the induction of a dendritic cell- and T-lymphocyte-dependent anticancer immune response. Here, we show that anthracycline-based chemotherapy promotes the recruitment of functional CD11b(+)CD11c(+)Ly6C(high)Ly6G(-)MHCII(+) dendritic cell-like antigen-presenting cells (APC) into the tumor bed, but not into lymphoid organs. Accordingly, draining lymph nodes turned out to be dispensable for the proliferation of tumor antigen-specific T cells within neoplastic lesions as induced by anthracyclines. In addition, we found that tumors treated with anthracyclines manifest increased expression levels of the chemokine Ccl2. Such a response is important as neoplasms growing in Ccl2(-/-) mice failed to accumulate dendritic cell-like APCs in response to chemotherapy. Moreover, cancers developing in mice lacking Ccl2 or its receptor (Ccr2) exhibited suboptimal therapeutic responses to anthracycline-based chemotherapy. Altogether, our results underscore the importance of the CCL2/CCR2 signaling axis for therapeutic anticancer immune responses as elicited by immunogenic chemotherapy.

Regulation of immune responses to HPVinfection and during HPV‐directed immunotherapy

Summary:  The recent development of vaccines prophylactic against human papillomavirus (HPV) infection has the potential to reduce the incidence of cervical cancer globally by up to 70% over the next 40 years, if universal immunization is adopted. As these prophylactic vaccines do not alter the natural history of established HPV infection, immunotherapies to treat persistent HPV infection and associated precancers would be of benefit to assist with cervical cancer control. Efforts to develop immuno‐therapeutic vaccines have been hampered by the relative non‐immunogenicity of HPV infection, by immunoregulatory processes in skin, and by subversion of immune response induction and immune effector functions by papillomavirus proteins. This review describes HPV‐specific immune responses induced by viral proteins, their regulation by host and viral factors, and highlights some conclusions from our own recent research.

Invariant NKT Cells in Hyperplastic Skin Induce a Local Immune Suppressive Environment by IFN-γ Production

NKT cells can promote or inhibit adaptive immune responses. Cutaneous immunity is tightly regulated by cooperation between innate and adaptive immune processes, but the role of NKT cells in regulating cutaneous immunity is largely unknown. In this study, we show, in a mouse model, that skin-infiltrating CD1d-restricted NKT cells in HPV16-E7 transgenic hyperplastic skin produce IFN-γ, which can prevent rejection of HPV16-E7–expressing skin grafts. Suppression of graft rejection is associated with the accumulation of CD1dhi-expressing CD11c+F4/80hi myeloid cells in hyperplastic skin. Blockade of CD1d, removal of NKT cells, or local inhibition of IFN-γ signaling is sufficient to restore immune-mediated graft rejection. Thus, inhibition of NKT cell recruitment or function may enable effective immunity against tumor and viral Ags expressed in epithelial cells.