Immunobiology of head and neck cancer: basic concepts

Neoantigens in immunotherapy and personalized vaccines: Implications for head and neck squamous cell carcinoma

The recent success of immunotherapies has demonstrated the potency of tumor-specific immune cells in mediating tumor rejection and generating durable tumor immunity. Our understanding of the scientific basis of these responses results from the confluence of a better comprehension of the cancer immunoediting process and the revolution in next generation sequencing of cancer genomes. Recent evidence suggests that T cell specificity for cancer cell expressed mutant proteins - termed neoantigens - is an important component of immune mediated tumor rejection. Improved neoantigen prediction algorithms have made it possible to predict and monitor immune responses to checkpoint inhibitors and adoptively transferred autologous lymphocytes and have enabled the development of tumor-specific therapeutic vaccines. Herein, we review the current research on cancer neoantigens in immunotherapies and its implications for the future of head and neck cancer management.

Gene therapy--phase I trial for primary untreated head and neck squamous cell cancer (HNSCC) UICC stage II-IV with a single intratumoral injection of hIL-2 plasmids formulated in DOTMA/Chol

Recombinant IL-2 protein has shown many immunostimulatory effects in a variety of human tumors. However, the clinical use of rIL-2 is limited by common and serious side effects after systemic administration. IL-2 expression plasmids may circumvent these drawbacks, producing high local IL-2 concentrations that cause limited or no systemic side effects. Due to the superficial growth of squamous cell carcinoma of the head and neck (HNSCC) are readily accessible for direct intratumoral injection and therefore an optimal target for such a gene therapy approach. There has been evidence for local and systemic activation of immune cells by peritumoral injections of IL-2 in patients with advanced HNSCC (Whiteside et al. 1993; Cortesina et al. 1994; De Stefani et al. 1996). We now perform a placebo-controlled, dose-rising study of the safety and tolerability of a single intratumoral injection of hIL-2 plasmid at four dose levels formulated in DOTMA/Chol in patients with primary untreated head and neck squamous cell cancer (HNSCC) TNM stage II-IV. The patients will be monitored for the occurrence of any adverse reactions to the given medication. In addition, we will determine whether the intratumoral administration of the plasmid induces and or enhances tumor-specific host responses at the immunological and or clinical level.

Role of arachidonic acid metabolites in tumor growth inhibition by nonsteroidal antiinflammatory drugs

PURPOSE

A murine model of squamous cell carcinoma (SCC) was used to determine the role of arachidonic acid (AA) metabolites in the growth of SCC of the head and neck.

MATERIALS AND METHODS

C3H/HeJ mice bearing SCC (SCC VII) were treated with cyclooxygenase inhibitors (piroxicam and nabumetone) or a 5-lipoxygenase inhibitor (ketoconazole). Growth curves were established, and final tumor weights were measured. Following sacrifice, tumor tissue homogenates were assayed for prostaglandin E2 (PGE2) and 12-hydroxyeicosatetraenoic acid (12-HETE) by enzyme-linked immunosorbent assay (ELISA), and leukotriene B4 (LTB4) by radioimmunoassay (RIA). Inflammatory cell infiltrate was assessed histologically.

RESULTS

A significant inhibition of tumor growth (P = .001) and final tumor weight (P = .002) was noted in mice treated with piroxicam and nabumetone. Inhibition of tumor growth was associated with increased tumor tissue levels of PGE2 (P = .04) and lymphocytic infiltration (P = .07). Significant inhibition of tumor growth (P = .002) and final tumor weight (P = .05) was also noted in mice treated with ketoconazole.

CONCLUSION

These data suggest that both cyclooxygenase and lipoxygenase metabolites of AA affect tumor growth in this model and that inhibition of tumor growth by inhibitors of AA metabolism may be caused by an enhanced inflammatory cell response at the tumor site.

Prognostic significance of prostaglandin E2 production in fresh tissues of head and neck cancer patients

BACKGROUND

Immunosuppressive prostaglandins may play a role in the biologic behavior of head and neck cancer. Increased levels of prostaglandin E2 (PGE2) have been measured in squamous cell carcinoma of the head and neck (SCCHN).

METHODS

To address this question, tissue levels of PGE2 were measured in tumor tissues, normal mucosa, and lymph nodes of 37 patients undergoing tumor resections. Tissue specimens were placed in culture media, and levels of PGE2 released into the supernatant were measured by radioimmunoassay.

RESULTS

Tissue levels of PGE2 were significantly greater in tumor and normal mucosal tissues compared to lymph nodes (p = 0.0003). There was no difference between metastatic and tumor-free lymph nodes. Although tumor tissue levels of PGE2 were not associated with tumor stage, increased levels of PGE2 were associated with increased 2-year disease-free survival (p = 0.02).

CONCLUSIONS

Although PGE2 may have adverse effects on local immune function in tumor tissues, improved survival of patients with increased local PGE2 production may be indicative of an enhanced immunologic response to the tumor which has a favorable impact on outcome.

Anti-proliferative activity of interferon-alpha on human squamous carcinoma of tongue cell lines

We evaluated the anti-tumour activity of human recombinant interferon-alpha (IFN-alpha) on two human squamous carcinoma of tongue cell lines (T2/CUHK and PWH-S1). The in vitro cytotoxicity was monitored by MTT assay. Continuous exposure to IFN-alpha alone at 500 IU/ml for 48 h produced inhibitory growth of 30% and 7% on T2/CUHK and PWH-S1 cell lines respectively. The ID50 of T2/CUHK cells was approximately 2500 IU/ml. PWH-S1 cells were resistant to treatment with interferon-alpha as 500 IU/ml IFN-alpha gave only 10% growth inhibition on PWH-S1 cells. IFN-alpha increased the anti-neoplastic activity of cisplatin and 5-FU against T2/CUHK cells, but the effect was less evident in PWH-S1 cells. Our findings support the further evaluation of IFN-alpha as a potent anti-proliferative cytokine therapy that may act synergistically with conventional chemotherapeutic agents for the treatment of squamous carcinoma of head and neck.

Comparison of in vivo and in vitro prostaglandin E2 production by squamous cell carcinoma of the head and neck

Prostaglandin E2 has been identified as an immunosuppressive factor in patients with squamous cell carcinoma of the head and neck. Spontaneous prostaglandin E2 production by 21 cancer cell lines, which were obtained from 17 patients with squamous cell carcinoma of the head and neck, was determined by radioimmunoassay. In comparison with normal keratinocyte cultures, prostaglandin E2 production by cancer cell lines was significantly decreased (p < 0.0001). Prostaglandin E2 levels demonstrated no correlation to the site, stage, or histopathologic differentiation of the tumor. In a separate group of 17 patients with squamous cell carcinoma of the head and neck, tumor cells were isolated from fresh tumor specimens, and 24-hour PGE2 production in vitro was assayed. No correlation was found with tumor site, stage, or 2-year disease-free survival. Although prostaglandin E2 may have biologic significance in vivo in patients with squamous cell carcinoma of the head and neck, these findings suggest that measurements of tumor cell-derived prostaglandin E2 are not predictive of biologic behavior.

Arachidonic acid metabolites in saliva of patients with squamous cell carcinoma of the head and neck

Alterations in the production of arachidonic acid metabolites by squamous epithelium of the upper aerodigestive tract may play a role in the pathogenesis of squamous cell carcinoma of the head and neck. The levels of cyclooxygenase and lipoxygenase metabolites of arachidonic acid metabolism were measured by radioimmunoassay in the saliva of 51 patients with squamous cell carcinoma of the head and neck and compared with a control group of 27 patients with no history of cancer. Levels of leukotriene B4 were significantly increased in cancer patients (p = 0.02), whereas there were no significant differences in levels of prostaglandin E2 or 15-hydroxy-eicosatetranoic acid. Levels of metabolites did not correlate with a history of tobacco use and did not change in a consistent manner after surgery. The significance of arachidonic acid metabolites in the saliva of patients with squamous cell carcinoma of the head and neck is unknown.

Phorbol dibutyrate plus ionomycin improves the generation of cytotoxic T cells from draining lymph nodes of patients with advanced head and neck cancer

Fifty-one cervical nodes from 19 patients with advanced head and neck cancer were stimulated with phorbol dibutyrate and ionomycin (PDBu + Io) to determine the effect of such stimulation on the generation of cytotoxic T cells and whether this stimulation could bypass the need for autologous tumor stimulation. Lymphocytes stimulated with PDBu + Io demonstrated a sixfold greater in vitro expansion and significantly increased DNA synthesis. Whereas fresh lymphocytes displayed no cytotoxicity, stimulation with PDBu + Io and culture in interleukin-2 (IL-2) led to significant cytotoxicity equivalent to that of lymphocytes stimulated with autologous tumor and IL-2. T cells with the greatest cytotoxicity were generated from patients with nodal metastases. In patients with stage IV tumors, effector cells demonstrating greater lysis of natural killer-resistant targets (Daudi cells) were associated with higher rates of recurrence (50% versus 12%, respectively, p < 0.001). Stimulation with PDBu + Io augments growth and proliferation of lymphocytes from draining lymph nodes and preserves cytotoxicity without the need for autologous tumor. Excluding the need for antigenic stimulation by autologous tumor may prove useful in adoptive immunotherapy procedures.

The absence of lymphoid suppressor cells in tumor-involved lymph nodes of patients with head and neck cancer

Patients with head and neck cancer often have decreased local or regional immunocompetence. Lymphocytes obtained from tumor-involved or -uninvolved lymph nodes (LNL) of these patients showed low or undetectable levels of antitumor cytotoxicity and low proliferative responses in vitro to interleukin 2 (IL2) or mitogens in comparison to peripheral blood lymphocytes (PBL). Lymphokine-activated killer (LAK) cell activity of LNL was lower (P less than 0.05) than that of autologous PBL. Fresh LNL were neither enriched in cells with the CD8+ CD11b+ "suppressor" phenotype nor did they suppress proliferative or cytotoxic responses of autologous PBL in mixing experiments. LNL did not inhibit LAK cell generation from autologous PBL in the presence of IL2. Also, no evidence for the inhibition of autotumor-restricted responses by IL2-activated LNL was obtained. Spontaneous or in vitro-induced production of IL1 beta. TNF alpha, and IFN-tau was low or undetectable in LNL from tumor-involved and -uninvolved lymph nodes in comparison to that in normal or autologous PBL. Mitogen-induced IL2 production was normal in LNL. The depressed ability to produce certain cytokines may be in part responsible for a state of unresponsiveness present in lymph nodes obtained from patients with head and neck cancer. No evidence for the presence of lymphoid suppressor cell in LNL of these patients was obtained.

An immunologic profile of young adults with head and neck cancer

Numerous reports have suggested, although never demonstrated, a suppressed immune defense mechanism as a contributing factor in the development of head and neck cancer in the young adult. Twenty-four previously untreated adults less than or equal to 40 years of age with squamous cell carcinoma were examined for lymphocyte function (natural killer cell activity and in vitro lymphocyte blastogenesis response to mitogens), total lymphocyte number and percentage of lymphocyte subsets, and humoral immune status (circulating IgA, IgG, and IgM). As compared with 33 healthy young adults, no significant immunologic deficit could be identified. On the contrary, the young adult cancer population had significantly increased lymphocyte numbers (P less than 0.05) and serum IgA, IgG, and IgM levels (P less than 0.001, respectively). These young cancer patients cannot be considered to be immunosuppressed. Alternative biologic mechanisms must be defined to account for the increasing incidence of head and neck cancer over the last decade among young adults in the United States.

Circulating IgA immune complexes in head and neck cancer, nasopharyngeal carcinoma, lung cancer, and colon cancer

A double antibody enzyme-linked immunosorbent assay (ELISA) was developed to quantitate circulating immune complexed IgA (IgA IC) in human serum. The serum panel for this study consisted of normal blood donors, benign surgery (BS), head and neck cancer (HN), nasopharyngeal carcinoma (NPC), lung cancer (LC), and colon cancer (CC) patients. Immune complexes (IC) were isolated from these sera by precipitation with 3.5% polyethylene glycol (PEG), washed and then redissolved in 0.1 M phosphate-buffered saline pH 7.2. The amount of IgA IC present were then quantified using the double antibody IgA ELISA. This assay was found to be both sensitive (26.0 ng/ml) and reproducible (intra-assay coefficient of variation 4.0%). The mean IgA IC for each cancer group tested (HN = 11.38 +/- 12.54 micrograms/ml; NPC = 13.36 +/- 17.56 micrograms/ml; LC = 17.39 +/- 13.04 micrograms/ml; CC = 26.50 +/- 4.60 micrograms/ml) were significantly elevated (P = 0.001) over both the normals (5.12 +/- 4.09 micrograms/ml) and the benign surgery controls (5.92 +/- 5.04 micrograms/ml). In addition to providing a new tumor marker the presence of high levels of IgA IC in cancer patients could provide a source of tumor-specific antibody as well as antigen and provide reagents to study immune regulation in cancer patients.

Systemic and regional natural cytotoxicity in patients with head and neck cancer

Forty patients with squamous carcinoma of the oral cavity (head and neck cancer) were investigated for natural killer-cell (NK) activity in peripheral blood (PB) and tumour-draining lymph nodes (LNs). For measuring NK activity a 4 hrs 51Cr release assay and K 562 target cells were used. Mononuclear cells of PB (PBMNC) and LNs (LNMNC) were separated by Ficoll Hypaque gradient centrifugation. NK activity was determined before tumour surgery. LNs were obtained either at the time of surgery of the primary tumour (en bloc neck dissection)--"immediately dissected LNs (ID-LNs)" or some time after removal of the primary tumour, especially for prophylactic purposes,--"delayed dissected LNs (DD-LNs)". Preoperatively, NK activity was clearly stage-dependent, patients with stages T1-2 displaying mean values similar to those of a control group without malignant disease, whereas values were significantly lower in patients with stages T3-4. Spontaneous cytotoxicity was significantly lower in LNMNC than in PBMNC of identical donors. NK activity was significantly lower in ID-LNs than in DD-LNs. These results suggest some negative influence of the primary tumour in the spontaneous cytotoxicity in both PB and tumour-draining LNs. In vitro incubation at +37 degrees together with addition of lymphoblastoid interferon (IFN-alpha) achieved a significantly stimulation of NK activity in both PBMNC and LNMNC.

Immune complexes, serum proteins, cell-mediated immunity, and immune regulation in patients with squamous cell carcinoma of the head and neck

A collaborative study of the humoral and cellular immune status of patients with carcinoma of the Head and Neck (H&N) was conducted at the West Virginia University (WVU) hospital. In addition, blind-coded serum panels were supplied on H&N cancer patients being treated at the National Cancer Institute (NCI). Serum protein analysis of the WVU study groups revealed that at the pretreatment sampling, the alpha-1 acid glycoprotein (AGP), total complement, and IgA levels were significantly elevated. The AGP levels and total complement levels declined to normal levels in the post-treatment period, whereas the IgA levels remained elevated throughout the entire observation period. Levels of serum immune complexes (SIC) were measured in both the WVU and NCI H&N cancer populations using the polyethylene glycol (PEG) precipitation method. In both survey populations all cancer groups had significantly elevated levels of SIC when compared to any of the control populations. The SIC levels never returned to comparative normal values even in cases after successful treatment. A subpopulation of the WVU-H&N cancer study group underwent a short course of intravenous hyperalimentation prior to their treatment regimen. These patients demonstrated a transient decrease in their SIC levels as well as a concomitant increase in their in vitro cell-mediated immune (CMI) correlates. The analysis of in vitro CMI correlates of the WVU study group using both polyclonal mitogens and specific antigens demonstrated a significant depression in these parameters pretreatment and post-treatment. In addition, it was observed that the time course for elevation of selected serum proteins (i.e., IgA and SIC) correlated with concomitant drops in CMI activity. Investigations were also conducted into the effects of immune complex-rich serum fractions upon selected in vitro CMI correlates. Significant blockage of a normal donor leukocyte migration-inhibition assay was demonstrated. Also, a similar inhibition of the ability of normal human lymphocytes to form high affinity rosettes was accomplished with serum from H&N cancer patients.

An animal model to investigate the interaction between the immune system and oral carcinomas

In an attempt to investigate the role of the immune system in oral squamous cell carcinoma, an animal model was developed with an inbred strain of mice. Well-differentiated oral squamous cell carcinomas were induced with a polycyclic hydrocarbon in immunogenetically identical mice. The oral tumors that developed were maintained in vivo. Once established, the tumors were adapted to tissue culture and the resulting cell lines were cloned. An immunization protocol was formulated to detect the generation of cytolytic effector cells by using a microcytotoxic chromium-51 release assay to assess the immune response of the host.

Secretory immune response in patients with oropharyngeal carcinoma

The secretory immune system is a unique, local immunological mechanism which appears to be independent of systemic immunity. Secretory immunoglobulin A (SIgA), a major component in this mucosal immune system, is structurally different from the IgA immunoglobulin in serum and has a function as a first line of defense against the uptake of macromolecules and against infectious agents in the intestine, respiratory tract and genitourinary system. However, its relationship to the development and control of neoplasia is not well understood despite the fact that the major portion of human malignancies are of the epithelial type and located where the secretory immune system is vigorously functioning. In this study, the amounts of SIgA and secretory component (SC) in oral secretions and sera were measured in 20 patients with oropharyngeal carcinoma and 22 appropriate control subjects in order to elucidate the involvement of the secretory immune system as it related to oropharyngeal carcinoma. Cancer patients had increased IgA levels in oral secretions (561 +/- 161 micrograms/ml) compared to normal subjects (166 +/- 18 micrograms/ml, p less than 0.02) and to a smoker/drinker subgroup of controls (229 +/- 8.7 micrograms/ml, p less than 0.05). The elevated IgA levels in cancer patients appear to be unrelated to local inflammation or the patient's history of smoking or drinking. Density gradient analysis demonstrated that the IgA measured in oral secretions migrates at the 11S position, confirming that it is of the secretory type and indicating that the increased levels of IgA in oral secretions of patients with oropharyngeal carcinoma are not due to nonspecific leakage of 7 SIgA from sera. Secretory component levels in sera also revealed highly significant differences between cancer patients (1.65 +/- 0.73 micrograms/ml) and all control subjects (0.85 +/- 0.12 micrograms/ml, p less than 0.002). The data suggest that the increased SIgA concentration in secretions and SC level in sera accompany the existence of oropharyngeal carcinoma. The biological significance of these findings and their possible clinical application are discussed.

Immunology of head and neck cancers

Despite the ever growing collection of data concerning the function of the immune system in patients with epidermoid carcinoma of the head and neck, the precise mechanism by which these tumors effect the body's surveillance against foreign antigen is as yet unidentified. If these specific immunological characteristics of the cancer cell can be identified, laboratory analysis of these "markers" could lead to detection and treatment of cancer in its earliest stages. Included in this chapter is a review of the embryological development of the immune system, a description of the components of the immune system and their responses to invasion by tumor antigen. Measurements of immuno responsiveness of the individual are important in determining the pretreatment state of immuno-competence and in predicting prognosis following treatment. Measurements of T-lymphocyte functions and their response to immuno-manipulations can also aid in predicting which patients will benefit from immunotherapy. Finally, categorization of the multiple forms of immunotherapy including active, specific and non-specific, and adoptive mechanisms are discussed. More recent methods of related immunotherapy trials will also be mentioned. As of this writing, the trials of immunochemotherapy have not produced any conclusive results due to the lack of multi-institutional trials and limited quantities of immunotherapeutic agents for these clinical trials.