Interferon alpha2b augments suppressed immune functions in tobacco-related head and neck squamous cell carcinoma patients by modulating cytokine signaling

HNSCC subverts PBMCs to secrete soluble products that promote tumor cell proliferation

The immune system detects shifts from homeostasis and eliminates altered cells. However, neoplastic cells can modulate the host response to escape immunosurveillance thereby allowing tumor progression. Head and neck squamous cell carcinoma (HNSCC) is one of the most immunosuppressive cancers but its role in co-opting the immune system to actively promote tumor growth has not been investigated. In this study, we investigated the influence of soluble factors secreted by HNSCC and non-neoplastic epithelial cells on proliferation, apoptosis, activation, cytokine gene expression and phenotypic polarization of immune cells of healthy donors. Then, we determined if the immunomodulation caused by HNSCC-derived soluble products leads to immunosubversion by assessing proliferation, migration and survival of tumor cells exposed to soluble products secreted by modulated immune cells or co-cultured with immune cells. Soluble products from HNSCC inhibited proliferation and cytokine expression in PBMCs, activation of T cells, and polarization of CD4+ towards the Th17 phenotype. These changes co-opted the immune cells to favor cell proliferation, survival and migration of HNSCC. This immunosubversion was observed both indirectly with secreted products and with direct cell-to-cell contact. We conclude that HNSCC-derived secreted products create an immunosuppressive environment that facilitates evasion of tumor cells and subverts the immune cells into a pro-tumoral phenotype.

The activation pattern of blood leukocytes in head and neck squamous cell carcinoma is correlated to survival

Head and neck squamous cell carcinoma (HNSCC) is known to cause substantial immunosuppression. The present study was designed to characterize blood leukocyte activation in HNSCC and to investigate if the individual activation pattern could be related to tumor progress and survival. The leukocyte activation profile of HNSCC patients and healthy controls was assessed with flow cytometry. HNSCC patients displayed increased numbers of monocytes, neutrophils and total leukocytes as well as an enhanced neutrophil/lymphocyte ratio. In addition, patients had a higher percentage of CD69⁺, CD71⁺ and CD98⁺ T cell subsets and NK cells, and a reduced expression of L-selectin in CD14^highCD16⁺ monocytes and neutrophils, when compared to controls. These changes could be correlated to both tumor burden and spread to lymph nodes. Among the cancer patients an increased neutrophil/lymphocyte ratio, a low neutrophil and CD14^high CD16⁺ monocyte activation state and an elevated CD4/CD8 ratio were related to poor survival. In contrast, a high percentage of CD98⁺ Th cells appeared to be associated with a better outcome. Taken together, the present data indicate that HNSCC causes activation of blood leukocytes and that the individual activation pattern can be linked to prognosis.

Dysregulated CC receptor/ligand in monocytes/macrophages from tongue squamous cell carcinoma patients is partially rectified by interferon α-2b

In an aim to rectify dysregulated CC chemokine receptor (CCR5)/ligand (RANTES, MIP-1α, MIP-1β) status of monocytes/macrophages in tongue squamous cell carcinoma (TSCC; n = 12) patients, we have tested interferon α2b (IFNα2b), a novel immunomodulator with wide use in the management of several forms of cancer. IFNα2b can upregulate reduced CCR5 expression and increases the suppressed secretory status of its ligands, as evidenced from in vitro studies on monocytes/macrophages from the peripheral blood of TSCC patients as well as healthy individuals. Isolated monocytes of TSCC patients (n = 5) undergoing chemotherapeutic treatment along with IFNα2b immunotherapy demonstrated significant upregulation in CCR5 expression and secretion of corresponding ligands. These rectifications in receptor/ligand levels are reflected in improved CCR5-dependent migration of monocytes/macrophages after IFNα2b treatment. The rectified chemokine profile and cellular migration translate into better tumoricidal and antigen-presenting functions of these cells. Accordingly, enhanced T-cell-mediated tumor cell killing is demonstrated upon IFNα2b treatment. Translating dual benefits on monocyte/macrophage functions, IFNα2b may emerge as a potential form of immunotherapy for TSCC patients that may be combined with standard chemotherapy for better clinical outcome.

Defective dendritic cell generation from monocytes is a potential reason for poor therapeutic efficacy of interferon α2b (IFNα2b) in cervical cancer

Despite being a pleiotropic cytokine, the therapeutic potential of interferon α2b (IFNα2b) is debatable. Thus, the need for identifying predictive marker(s) for patients who are most likely to benefit from the treatment is pivotal for avoiding the exposure of nonresponsive patients to the toxicity of the treatment. To account for the attenuated efficacy of the drug, we have verified its dendritic cell (DC) maturating ability from monocytes of cervical cancer stage IIIB (CaCx-IIIB) patients. First, we evaluated the status of monocytes from CaCx-IIIB and healthy women by conducting flow cytometric studies of various activation markers and a cytokine analysis by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Immature DCs were then generated from these monocytes and matured with low-dose IFNα2b (1500 units/mL). A functional and phenotypic comparative analysis of these matured DCs was performed by flow cytometric, proliferative, cytotoxic, and enzyme-linked immunosorbent assays. Our study shows that monocytes isolated from CaCx-IIIB are impaired, and in vitro maturation with IFNα2b did not significantly improve the functional repertoire of DCs generated from these monocytes in comparison with healthy controls. This impairment of monocytes might be a plausible reason for the attenuated efficacy of this drug alone in treating CaCx-IIIB patients, and this imbalance of immune parameters associated with the stage of malignancy might be considered an effective marker to design a proper therapeutic regimen.

Neem leaf glycoprotein induces perforin-mediated tumor cell killing by T and NK cells through differential regulation of IFNgamma signaling

We have demonstrated augmentation of the CD3-CD56+ natural killer (NK) and CD8+CD56_ T-cell-mediated tumor cell cytotoxicity by neem leaf glycoprotein (NLGP). These NK and T cells were isolated from the peripheral blood of head and neck squamous cell carcinoma patients with a state of immunosuppression. NLGP induces TCRalphabeta-associated cytotoxic T lymphocyte (CTL) reaction to kill oral cancer (KB) cells. This CTL reaction is assisted by NLGP-mediated up-regulation of CD28 on T cells and HLA-ABC, CD80/86 on monocytes. CTL-mediated killing of KB cells and NK-cell-mediated killing of K562 (erythroleukemic) cells are associated with activation of these cells by NLGP. This activation is evidenced by increased expression of early activation marker CD69 with altered expression of CD45RO/CD45RA. NLGP is a strong inducer of IFNgamma from both T and NK cells; however, IFNgamma regulates the T-cell-mediated cytotoxicity only without affecting NK-cell-mediated one. Reason of this differential regulation may lie within up-regulated expression of IFNgamma-receptor on T-cell surface, not on NK cells. This NLGP-induced cytotoxicity is dependent on up-regulated perforin/granzyme B expression in killer cells, which is again IFNgamma dependent in T cells and independent in NK cells. Although, FasL expression is increased by NLGP, it may not be truly linked with the cytotoxic functions, as brefeldin A could not block such NLGP-mediated cytotoxicity, like, concanamycin A, a perforin inhibitor. On the basis of these results, we conclude that NLGP might be effective to recover the suppressed cytotoxic functions of NK and T cells from head and neck squamous cell carcinoma patients.

Neem leaf glycoprotein directs T-bet-associated type 1 immune commitment

Neem leaf glycoprotein (NLGP)-mediated immune activation and associated immune polarization was studied. NLGP-induced activation is reflected in upregulation of early activation marker CD69 on lymphocytes, monocytes, and dendritic cells. Activation is also denoted by CD45RO enhancement, with a decrease in CD45RA phenotype and CD62L (L-selectin). NLGP-activated T cells secrete greater amount of signature T-helper (Th)1 cytokines interferon-gamma and a lower amount of the Th2 cytokine interleukin (IL)-4. Similar type 1 directiveness is also observed in antigen-presenting monocytes and dendritic cells by upregulation of IL-12, tumor necrosis factor -alpha and downregulation of IL-10. Creation of the type 1 microenvironment is also assisted by NLGP-induced downregulation of FoxP3(+) T-Reg cells. A type 1-specific transcription factor, T-bet, is upregulated in circulating immune cells after their stimulation with NLGP. In the creation of type 1 immune network, increased phosphorylation of STAT1 and STAT4 with decreased phosphorylation of STAT3 might have significance. We conclude that NLGP may be effective in maintaining normal immune homeostasis by upregulating type 1 response in immunosuppressed hosts, which may have significant role in the induction of host protective antitumor functions.

Toxicity as a result of immunostimulation by biologics

The immune system has evolved highly effective mechanisms of surveillance and defense against foreign pathogens, and is also thought to act in surveillance and suppression of cancer. Thus, a predominant goal of immune system-based therapies is to normalize or enhance the host immune response in the areas of infectious disease and oncology. This review considers general approaches used for therapeutic immunostimulation, alterations in immune response mechanisms that occur with these treatments and the syndromes that commonly arise as a result of these changes. Because nonclinical studies of these therapies are conducted in animal models as the basis for predicting potential human toxicities, this review also considers the value of nonclinical testing to predict human toxicity.

Recent advances in Oral Oncology

This paper reviews the main papers related to oral squamous cell carcinoma published in 2006 in oral oncology - an international interdisciplinary journal which publishes high quality original research, clinical trials and review articles, and all other scientific articles relating to the aetiopathogenesis, epidemiology, prevention, clinical features, diagnosis, treatment and management of patients with neoplasms in the head and neck, and orofacial disease in patients with malignant disease.

IFNα2b stimulated release of IFNγ differentially regulates T cell and NK cell mediated tumor cell cytotoxicity

Interferonalpha2b (IFNalpha2b) augments the suppressed immune functions and peripheral blood mononuclear cell (PBMC) cytotoxicity of head and neck squamous cell carcinoma (HNSCC) patients by differential regulation of IFNgamma, a pleotropic Th1 cytokine. In the present communication, we have examined the role of IFNgamma in IFNalpha2b initiated T and NK cell mediated cytotoxicity of tumor cells. IFNalpha2b activates both T and NK cells to release IFNgamma. IFNgamma plays a crucial role in enhancing tumor cell cytotoxicity by T cells, but not by NK cells, as evidenced by killing of a oral (KB) and breast (MCF7) cancer cells, without affecting the killing of NK sensitive erythroleukemic K562 cells by IFNalpha2b activated PBMC. IFNalpha2b driven tumor cell cytotoxicity is related to the rectification of the downregulated expression of cytotoxic molecules, perforin, granzyme B and FasL in CD8+ T and CD56+ NK cells. Expression of IFNalpha2b mediated perforin and granzyme B is dependent on IFNgamma in T cells, but not in NK cells. However, expression of FasL in both T and NK cells is not dependent on IFNgamma. In conclusion, IFNalpha2b enhances suppressed T cell cytotoxicity of HNSCC patients by stimulating perforin-granzyme B system, which is IFNgamma dependent. IFNalpha2b also induces the expression of perforin-granzyme B system in NK cells, but this NK mediated cytotoxicity is IFNgamma independent.