Costimulation-based immunotherapy for head and neck cancer

The role of antagonists of the PD-1:PD-L1/PD-L2 axis in head and neck cancer treatment

We review the current clinical knowledge surrounding one of the most promising immune checkpoint pathways currently investigated in head and neck squamous cell carcinoma patients, programmed cell death-1 (PD-1) and its ligands (PD-L1 and PD-L2). We review ongoing clinical trials and associated clinical responses observed with targeting the receptor, PD-1, and its ligand, PD-L1. A recent phase III clinical trial (Checkmate 141) demonstrated an improved overall survival in head and neck cancer patients treated with anti-PD-1 monotherapy as compared to standard of care for recurrent and/or metastatic disease, which raises questions on how best to incorporate immunotherapy in the context of standard of care. We discuss biomarkers of response to this class of novel drugs, which is an area of active investigation. Lastly, we project future directions in the field wherein understanding how the Fc portions of the various monoclonal antibodies may impact their clinical efficacy as well as discuss areas where our next advances may take place, such as combination strategies.

Immunologic checkpoints blockade in renal cell, prostate, and urothelial malignancies

Genitourinary (GU) tumors, and in particular renal cell and prostate cancer, represent one of the most dynamic areas in oncology from the scientific point of view. One of the most recent treatment approaches for GU tumors has focused on a series of molecules known as immune checkpoints and the possibility of manipulating immune responses against tumor cells by blocking these molecules with monoclonal antibodies (mAbs). Cytotoxic T lymphocyte antigen-4 (CTLA-4), and the immune checkpoint inhibitor mAbs ipilimumab and tremelimumab, represent the prototypes of this new growing class of agents called immunomodulating antibodies, while programmed death/ligand 1 (PD-1/PD-L1) also has garnered a significant interest as a new immune checkpoints to target in urothelial cancer, with the anti-PD-1/PD-L1 inhibitor mAbs nivolumab, MPDL-3280, and BMS-936559 as the first agents tested. Here we report the encouraging initial data observed in GU cancers with this new class of agents, which have reinforced the interest of investigating the therapeutic potential of the immune checkpoint modulators in large controlled trials.

Inhibitors of B7-CD28 costimulation in urologic malignancies

T-cell costimulatory molecules deliver positive or negative signals to govern the ultimate fate of immune responses. These ligands and receptors that negatively costimulate T cells (including cytotoxic T-lymphocyte antigen [CTLA]-4, B7-H1, programmed death [PD]-1, B7-H3 and B7x) have received significant interest recently owing to their proposed ability to form a molecular shield for tumor cells. CTLA-4 represents the most extensively studied receptor in the costimulatory pathway and functions as a potent inhibitor of T-cell-mediated immunity. Clinical trials with anti-CTLA-4 are ongoing, although numerous objective responses have been observed in heavily pretreated patients, albeit with autoimmune side effects. In renal cell carcinoma, B7-H1, PD-1 and B7x have been observed to be expressed on tumor cells or infiltrating lymphocytes and are individually associated with adverse pathologic features and poor clinical outcome. In prostate cancer, B7-H3 and B7x immunostaining intensity correlate with disease spread, clinical cancer recurrence and cancer-specific death. External validation and prospective studies are now needed to confirm these findings, while further development of humanized monoclonal antibodies, similar to the experience with anti-CTLA-4, are underway. Herein, we review the B7-CD28 family as it applies to urologic malignancies.

Progress and challenges in the vaccine-based treatment of head and neck cancers

Head and neck (HN) cancer represents one of the most challenging diseases because the mortality remains high despite advances in early diagnosis and treatment. Although vaccine-based approaches for the treatment of advanced squamous cell carcinoma of the head and neck have achieved limited clinical success, advances in cancer immunology provide a strong foundation and powerful new tools to guide current attempts to develop effective cancer vaccines. This article reviews what has to be rather what has been done in the field for the development of future vaccines in HN tumours.

Isopentenyl pyrophosphate-activated CD56+ {gamma}{delta} T lymphocytes display potent antitumor activity toward human squamous cell carcinoma

PURPOSE

The expression of CD56, a natural killer cell-associated molecule, on alphabeta T lymphocytes correlates with their increased antitumor effector function. CD56 is also expressed on a subset of gammadelta T cells. However, antitumor effector functions of CD56(+) gammadelta T cells are poorly characterized.

EXPERIMENTAL DESIGN

To investigate the potential effector role of CD56(+) gammadelta T cells in tumor killing, we used isopentenyl pyrophosphate and interleukin-2-expanded gammadelta T cells from peripheral blood mononuclear cells of healthy donors.

RESULTS

Thirty to 70% of expanded gammadelta T cells express CD56 on their surface. Interestingly, although both CD56(+) and CD56(-) gammadelta T cells express comparable levels of receptors involved in the regulation of gammadelta T-cell cytotoxicity (e.g., NKG2D and CD94), only CD56(+) gammadelta T lymphocytes are capable of killing squamous cell carcinoma and other solid tumor cell lines. This effect is likely mediated by the enhanced release of cytolytic granules because CD56(+) gammadelta T lymphocytes expressed higher levels of CD107a compared with CD56(-) controls following exposure to tumor cell lines. Lysis of tumor cell lines is blocked by concanamycin A and a combination of anti-gammadelta T-cell receptor + anti-NKG2D monoclonal antibody, suggesting that the lytic activity of CD56(+) gammadelta T cells involves the perforin-granzyme pathway and is mainly gammadelta T-cell receptor/NKG2D dependent. Importantly, CD56-expressing gammadelta T lymphocytes are resistant to Fas ligand and chemically induced apoptosis.

CONCLUSIONS

Our data indicate that CD56(+) gammadelta T cells are potent antitumor effectors capable of killing squamous cell carcinoma and may play an important therapeutic role in patients with head and neck cancer and other malignancies.

Galectins as modulators of tumor progression in head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCCs) remain a significant cause of morbidity worldwide. Biological therapies able to induce and/or upregulate antitumor immune responses could represent a complementary approach to conventional treatments for patients with HNSCC because, despite advances in surgery, radiotherapy, and chemotherapy, the overall survival rates for these patients have not changed over recent decades. Galectins are involved in the control of cell proliferation, cell death, and cell migration and in the modulation of various functions of the immune system. In this context, galectin-1 is known to protect HNSCCs from the immune system. The present review details the involvement of galectins in HNSCC biology and suggests a number of approaches to reduce the levels of expression of galectin-1 in HNSCCs, with the aim of improving the efficiency of HNSCC immunotherapy.

Vaccine-based approaches to squamous cell carcinoma of the head and neck

Vaccine-based approaches for the treatment of advanced squamous cell carcinoma of the head and neck have achieved very limited success. Improvement in vaccine efficacy for both diseases control and survival is predicated on a careful analysis of the root causes for successes and failures to date. In this review, we analyse the utility and limitations of select protective and therapeutic vaccine strategies for tumour prevention and therapy. Based on this characterisation, we define potential directions which are meritorious of future study.

B7-H1-targeted immunotherapy for head and neck cancer

Manipulation of defined costimulatory pathways may provide a means to direct the immune response against head and neck cancer. Three broad hurdles serve as relative obstacles to effective clinical translation of reagents designed to alter costimulatory function. First is an expanding, but still limited, understanding of the biological function of each individual costimulatory pathway. Second is the paucity of reagents suitable for clinical application. Third is the limited number of valid model systems to evaluate the utility of these novel reagents prior to clinical intervention. This review focuses on the role of a recently discovered costimulatory molecule, B7-H1, as a model for the development of novel strategies for immunotherapy of head and neck cancer.

Development and immunophenotyping of squamous cell carcinoma xenografts: tools for translational immunology

OBJECTIVES/HYPOTHESIS

The objectives of this study were to delineate methods for the development of primary squamous cell carcinoma (SCCHN) xenografts and to define human leukocyte antigen (HLA), melanoma-associated antigen (MAGE)-A3, and human papilloma virus (HPV) 16 antigenic expression in resultant cellular products.

STUDY DESIGN

Prospective experimental model.

METHODS

Freshly isolated SCCHN xenografts were established in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice using a variety of methods. Resultant tumors were analyzed for expression patterns of HLA-A, MAGE-A3, and HPV 16. Appropriate controls were included to ensure the presence of human RNA.

RESULTS

Three xenografts were successfully established and passaged in vivo. Characterization of the resultant products revealed that one was positive for HLA-A2 at both the DNA and protein levels. One of the tumor lines expressed MAGE-A3, whereas none expressed HPV 16.

CONCLUSIONS

Freshly isolated SCCHN can be used to generate primary xenografts. Characterization of select patterns of protein expression in established xenografts is a precursor to the development of a mouse model for SCCHN using tumor bearing animals reconstituted with autologous patient leukocytes.

Immunity to squamous carcinoma in mice immunized with dendritic cells transfected with genomic DNA from squamous carcinoma cells

Immunotherapy of squamous cell carcinoma (SCC) at an early stage of the disease increases the likelihood of success. We report a new vaccination strategy designed to prepare SCC vaccines from microgram amounts of tumor tissue, enabling the treatment of patients with minimal residual disease. The vaccine was prepared by transfer of sheared genomic DNA-fragments (25 kb) from KLN205 cells, an SCC cell line of DBA/2 mouse origin, into syngeneic bone marrow-derived mature dendritic cells (DCs). More than 90% of the transfected DCs took up DNA from the neoplasm and transferred genes were expressed as protein. The DCs expressed CD11c, CD11b, and the costimulatory molecules CD40, CD80 and CD86, characteristic of mature DCs. Syngeneic DBA/2J mice, highly susceptible to the growth of KLN205 cells, were injected intravenously (i.v.) with the transfected DCs, followed by a subcutaneous (s.c.) injection of the tumor cells. The strong immunogenic properties of the transfected cells were indicated by the finding that the survival of the tumor-bearing mice was prolonged (P<.001), relative to that of mice in various control groups. Enzyme-linked immuno spot (ELISPOT IFN-gamma) assays revealed the activation of cell-mediated immunity directed toward the SCC in mice immunized with the transfected DCs. Two independent in vitro cytotoxicity assays indicated the presence of robust cell-mediated immunity directed toward the SCC in mice immunized with the transfected cells.

Costimulatory B7-H1 in renal cell carcinoma patients: Indicator of tumor aggressiveness and potential therapeutic target

Expression of B7-H1, a costimulating glycoprotein in the B7 family, is normally restricted to macrophage-lineage cells, providing a potential costimulatory signal source for regulation of T cell activation. In contrast, aberrant expression of B7-H1 by tumor cells has been implicated in impairment of T cell function and survival, resulting in defective host antitumoral immunity. The relationship between tumor-associated B7-H1 and clinical cancer progression is unknown. Herein, we report B7-H1 expression by both renal cell carcinoma (RCC) tumors of the kidney and RCC tumor-infiltrating lymphocytes. In addition, our analysis of 196 clinical specimens reveals that patients harboring high intratumoral expression levels of B7-H1, contributed by tumor cells alone, lymphocytes alone, or tumor and/or lymphocytes combined, exhibit aggressive tumors and are at markedly increased risk of death from RCC. In fact, patients with high tumor and/or lymphocyte B7-H1 levels are 4.5 times more likely to die from their cancer than patients exhibiting low levels of B7-H1 expression (risk ratio 4.53; 95% confidence interval 1.94-10.56; P < 0.001.) Thus, our study suggests a previously undescribed mechanism whereby RCC may impair host immunity to foster tumor progression. B7-H1 may prove useful as a prognostic variable for RCC patients both pre- and posttreatment. In addition, B7-H1 may represent a promising target to facilitate more favorable responses in patients who require immunotherapy for treatment of advanced RCC.