Inhibition of lymphokine-activated killer cell generation by blocking factors in sera of patients with head and neck cancer

Immunosuppressive Factors: Role in Cancer Development and Progression

The concept of the immunological surveillance against neoplastic cells was initially proposed by Erlich in 1909 and later elaborated by Burnet. This hypothesis states that the normal function of the immune system, in particular the cell-mediated immunity, is to recognize and destroy the transformed and proliferating tumor cells. The role of cell-mediated immunity during the first steps of tumorigenesis remains controversial. However, there is certain evidence about its importance in the progression and dissemination of cancer. The frequent immunosuppressed condition of cancer patients at tumor relapse or recurrence of secondary tumors is a clinical sign supporting this hypothesis, and many studies have demonstrated a defective immune response in patients diagnosed with advanced cancer. Several mechanisms of escape from the immune surveillance have been described, including the immunoselection of tumor antigen-negative variants, the downregulation of MHC class I expression, suppressive T cells, and the elaboration of immunosuppressive cytokines and other factors. Because of the technical difficulty of isolating the very small amounts from culture supernatants or body fluids, only a few of these substances have been characterized and studied with respect to their biological activity: transforming growth factor-β (TGF-β), the protein p15E, interleukin 10 (IL-10), prostaglandin E2 (PGE2), mucins, suppressive E-receptor (SER), immunosuppressive acidic protein (IAP), and adhesion molecules. The possibility of monitoring cancer patients by testing biochemical factors related to cancer growth led to a proposal to measure a number of these factors as tumor markers. Some of them, e.g mucins, enjoy the consensus of the oncologic community, as for some indications they can help the clinician in the management of cancer patients. Except for the class of mucins, the other above-mentioned immunosuppressive factors have not found any clinical application in the laboratory routine because the information deriving from their measurement, although of speculative and scientific interest, has limited clinical value at present. Nevertheless, even if they have no impact on patient management, these substances do have a potential role to play in the study of cancer patients, and should be taken into account when developing new therapeutic strategies.

[Immunotherapy of head and neck cancer. Current developments]

In order to improve the prognosis for patients with head and neck squamous cell cancer (HNSCC) the introduction of new therapeutic strategies is necessary. The concept of immunotherapy has been applied and improved for several years and recent studies have used tumor-specific antigens which facilitates targeted oncologic therapy. However, immunotherapy is hampered by the fact that immunosuppressive mechanisms are pronounced and relevant effector cells are suppressed, especially in patients with HNSCC. Successful immunotherapy could induce an antitumor immune response by restitution of these cell populations. Current anti-tumor immunotherapy includes unspecific immune stimulation, genetic modification of tumor and immune cells, the use of monoclonal antibodies, e.g. cetuximab, adoptive cell transfer and tumor vaccination. In the future, these biologic therapies alone or in combination with conventional therapeutic regimens could present a valuable therapeutic option for HNSCC patients.

Immune therapies for neuroblastoma

Neuroblastoma, a solid tumor arising from developing cells of the sympathetic nervous system, is the most common extracranial tumor in children. The prognosis for high-risk neuroblastoma remains poor with conventional treatment, and new approaches are therefore being explored to treat this disease. One such alternative therapy that holds promise is immune therapy. We review here the recent advances in four types of immune therapy-cytokine, vaccine, antibody and cellular therapy-to treat neuroblastoma. We present preclinical research and clinical trials on several promising candidates such as IL-12, dendritic cell vaccines, anti-GD2 antibodies and allogeneic hematopoietic stem cell transplant. An optimal treatment plan for neuroblastoma will most likely involve multimodal approaches and combinations of immune therapies.

Plattenepithelkarzinome des Kopf-Hals-Bereichs

Biologic therapies able to induce or up-regulate anti-tumor immune responses could represent a complementary approach to improve the conventional treatment of squamous cell carcinomas of the head and neck (SCCHN). Patients with SCCHN are frequently immunocompromised due to the elimination and dysfunction of critical immune effector cells. Therefore, it might be necessary to restore these immune functions to allow for the generation of effective anti-tumor host responses. Simultaneously, to prevent tumor escape from immunological recognition and destruction, it might also be necessary to alter antigenic and immunogenic attributes of the malignant cells. The present overview summarizes general aspects, historical data, and recent advances in the field of immunotherapy of SCCHN, including non-specific immune stimulation, transfer of immunocompetent cells, gene therapy, use of monoclonal antibodies, and anti-cancer vaccines.

Revisiting immunosurveillance and immunostimulation: Implications for cancer immunotherapy

Experimental and clinical experience demonstrates that the resolution of a pathogenic challenge depends not only on the presence or absence of an immune reaction, but also on the initiation of the proper type of immune reaction. The initiation of a non-protective type of immune reaction will not only result in a lack of protection, but may also exacerbate the underlying condition. For example, in cancer, constituents of the immune system have been shown to augment tumor proliferation, angiogenesis, and metastases. This review discusses the duality of the role of the immune system in cancer, from the theories of immunosurveillance and immunostimulation to current studies, which illustrate that the immune system has both a protective role and a tumor-promoting role in neoplasia. The potential of using chemotherapy to inhibit a tumor-promoting immune reaction is also discussed.

Targeting the immune system: novel therapeutic approaches in squamous cell carcinoma of the head and neck

Despite advances in surgery, radiotherapy, and chemotherapy, the overall survival rates for patients with squamous cell carcinoma of the head and neck (SCCHN) have not changed over the last decades. Clearly, novel therapeutic strategies are needed for this cancer, which is highly immunosuppressive. Therefore, biologic therapies able to induce and/or up-regulate antitumor immune responses could represent a complementary approach to conventional treatments. Because patients with SCCHN are frequently immunocompromised due to the elimination or dysfunction of critical effector cells of the immune system, it might be necessary to restore these immune functions to allow for the generation of more effective antitumor host responses. Simultaneously, to prevent tumor escape, it might be necessary to alter attributes of the malignant cells. The present review summarizes recent advances in the field of immunotherapy of SCCHN, including techniques of nonspecific immune stimulation, the use of monoclonal antibodies, advances in adoptive immunotherapy and genetic engineering, as well as anticancer vaccines. These biologic therapies, alone or in combination with conventional treatment, are likely to develop into useful future treatment options for patients with SCCHN.

Neuroblastoma and dendritic cell function

Neuroblastoma, the most common extracranial solid tumor of childhood, remains a challenge for clinicians and investigators in pediatric surgical oncology. The absence of effective conventional therapies for most patients with neuroblastoma justifies the application of novel, biology-based, experimental approaches to the treatment of this deadly disease. The observation that some aggressive neuroblastomas, particularly in infants, may spontaneously regress suggested that immune-mediated mechanisms may be important in the biology of this disease. Advances in the understanding of the cognate interactions between T cells, antigen-presenting cells and tumors have demonstrated the sentinel role of dendritic cells (DC), the most potent antigen presenting cells, in initiating the cellular immune response to cancer. Until recently the function of DC in pediatric solid tumors, especially neuroblastoma, had not been extensively studied. This review discusses the role of DC in initiating and coordinating the immune response against cancer, the ability of neuroblastoma to induce DC dysregulation at multiple levels by inhibiting DC maturation and function, and the current vaccine strategies being designed to employ the unique ability of DC to promote neuroblastoma regression.

Advanced neuroblastoma impairs dendritic cell function in adoptive immunotherapy

BACKGROUND/PURPOSE

The authors previously described the complete regression of established neuroblastoma (NB) by the adoptive transfer of syngeneic interleukin-12 transduced dendritic cells (DC) from naive mice. However, some malignancies, like NB, abrogate DC immunostimulation. The authors hypothesize that IL-12 transduction of DC from NB-bearing mice will have the same antitumor properties.

METHODS

A/J mice (n = 32) with established NB received peritumoral injection of 1 x 10(6) DC (DC, IL-12 DC, day 7 IL-12 DC or day 14 IL-12 DC) on day 7. Tumor growth, phenotype, and ability to induce NK and T cell activity were measured.

RESULTS

Vaccination with naive admIL-12 DC resulted in 100% tumor regression and prolonged survival. Transduced DC induced only partial responses in 75% (day 7) and 25% (day 14) of animals. No differences in phenotype or effector cell activation were noted between admIL-12DC in tumor-bearing or naive mice.

CONCLUSIONS

IL-12 DC from tumor-bearing animals have a decreased ability to induce antitumor activity against established murine NB. This decreased capacity appears to be related to the duration of exposure to tumor because day 14 transduced DC had less of an effect than day 7 DC, despite similar phenotypes and ability to activate immune effector cells.

Inhibition of CD40 expression and CD40-mediated dendritic cell function by tumor-derived IL-10

As CD40 plays a key role in both antitumor immunity and DC maturation, we have studied the regulation of its expression during DC hematopoiesis (dendropoiesis) in vitro and in vivo in the tumor microenvironment. Using MC38 colon adenocarcinoma tumor models, we have demonstrated that DCs generated in vitro from bone marrow precursors obtained from tumor-bearers have significantly lower expression of CD40 molecules compared to DCs generated from tumor-free mice. Furthermore, CD40 expression on DCs isolated from the spleens of tumor-bearing mice was also significantly reduced, suggesting that tumor-derived factors inhibit CD40 expression on DCs during dendropoiesis both in vitro and in vivo. Interestingly, CD40 ligation on DCs generated from tumor-bearers did not result in inducible expression of IL-12 protein or IL-12 p40 mRNA. However, Staphylococcus aureus-induced IL-12 production by DCs was not altered in tumor-bearers, confirming that inhibition of IL-12 production by DCs generated in vitro from tumor-bearing mice was due to reduced expression of CD40 on DCs. We have also shown that MC38 tumor cells produce IL-10 and that exogenous IL-10 causes downregulation of CD40 expression on DCs. In addition, endogenous IL-10 produced by colon carcinoma cells inhibited CD40-dependent IL-12 production by DCs since tumor-induced inhibition of IL-12 production was abrogated by neutralizing anti-IL-10 antibody. Finally, systemic administration of FLT3L and/or CD40L reversed CD40 and IL-12 (p40) deficiency of DCs in tumor-bearing mice in vivo. These findings thus demonstrate that tumor-derived factors, including IL-10, inhibit CD40 expression on DCs and DC precursors and suppress their maturation and function.

Interleukins 7 and 12 are expressed in head and neck squamous cancer

Interleukin 7 (IL-7) and IL-12 have major roles in cell-mediated tumour immunity. In head and neck squamous cell cancer, depressed cell-mediated immunity is well documented and may account for the poor prognosis. This is the first study to assess intratumour expression of IL-7 and IL-12 in head and neck squamous cell cancer (HNSCC). Immunohistochemistry was used to identify IL-7 and IL-12 expression in snap-frozen tumour specimens from 25 patients with HNSCC and the results of immunohistochemical staining were semiquantitatively graded. Both IL-7 and IL-12 were expressed in all tumour samples and expression was not related to tumour stage or site. A trend towards better survival was associated with high expression of IL-7 and IL-12, this being more pronounced with IL 7. The universal expression suggests that the depressed cell-mediated immunity in HNSCC is not caused by reduced production of IL-7 and IL-12. Further studies with larger cohorts, especially of IL-7, are certainly warranted.

Relationship between progression of disease and immunoglobulin A-anti-Fab-/F(ab')2 autoantibodies in patients with head and neck cancer

Patients with malignant tumors of the head and neck often have immune defects. Higher serum immunoglobulin (Ig)A levels were reported in this group of patients. We investigated whether IgA-anti-Fab- or IgA-anti-F(ab')2 autoantibodies, which have been shown to correlate with severe dysfunction of the immune system, also appear in patients with head and neck cancer. Sera of 110 patients with squamous cell carcinoma (SCCHN), eight patients with adenoid cystic carcinoma, and 57 healthy control subjects were tested by enzyme-linked immunosorbent assay for IgA-anti-Fab autoantibody activity. Patients with head and neck cancer showed a higher IgA-anti-Fab activity (optical density (OD) = 399; n = 118) than did healthy control subjects (OD = 84; n = 57; p < 0.0001). An association between stage of disease and IgA-anti-Fab activity could be established in patients with SCCHN. Patients with stage IV disease had a significantly higher IgA-anti-Fab activity (OD = 538; n = 51) than had patients with stage I disease (OD = 283; n = 18; p < 0.05). Patients with stage II (OD = 293; n = 13) or stage III (OD = 379; n = 28) disease had intermediate activity. Also a higher IgA-anti-Fab activity than in healthy control subjects could be shown in the eight patients with adenoid cystic carcinoma (OD = 314; n = 8; p < 0.01). The highest IgA-anti-Fab activity was observed in eight patients with SCCHN who died within 6 months after testing (OD = 1004; n = 8), suggesting an association between autoimmunity and final desintegration of physiologic body functions. The occurrence of IgA-anti-Fab/IgA-anti-F(ab')2 autoantibodies might be interpreted as an aspect of immune deficiency in patients with malignant tumors of the head and neck.

Interleukin-10 as a possible mediator of immunosuppressive effect in patients with squamous cell carcinoma of the head and neck

BACKGROUND

Depressed cell-mediated immunity is a frequent event in patients with head and neck cancer and is characterized by impairment of T cell-proliferative responses and natural killer cell and lymphokine-activated killer cell activity. This immunosuppressive effect appears to be mediated by a serum-derived factor. Certain cytokines, including transforming growth factor-beta (TGF-beta) and interleukin (IL)-10 have been shown to induce similar immunosuppressive effects. The present study was designed to examine the putative role of these cytokines in cellular immune suppression induced by patient serum.

METHODS

Serum was collected from multiple patients with newly diagnosed or recurrent squamous cell carcinoma of the head and neck. The serum was heat inactivated for 30 min and frozen in aliquots. Peripheral blood lymphocytes were isolated from normal human blood. Lymphocytes were suspended in RPMI and 15% concentrations of control and patient serum and stimulated with 0.75 mg% phytohemagglutinin. In addition, neutralizing antibodies to TGF-beta and IL-10 were added to lymphocyte cultures. At 24 h, and IL-2 response assay was performed. Finally, the sera were examined for the presence of TGF-beta and IL-10 using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

In seven of seven experiments, incubating cells with a neutralizing antibody to TGF-beta failed to counteract the immune suppression and restore proliferative response to IL-2. Also, an ELISA of these sera failed to demonstrate the presence of TGF-beta. In contrast, four of five experiments performed with neutralizing antibody to IL-10 showed significant restoration of proliferation in the presence of this antibody. Also, ELISA showed elevated IL-10 levels in 65% of the patients' sera in comparison to controls.

CONCLUSION

We conclude that TGF-beta is not responsible for the immunosuppressive effects induced by head and neck patient sera. However, the suppressive effect is reversed by blocking the biologic action of IL-10. Further experiments are needed to define the role of IL-10 in inducing the immunosuppressive effect.

Inhibitory activity of soluble IL-2R in sera, ascites and culture supernatants from murine leukaemic cells

The effect of sera from mice bearing a T cell lymphoid leukaemia (LB) and the supernatants from short term cultures of the tumour cells were studied on cell proliferation using syngeneic and allogeneic normal and tumour cells. An inhibitory activity was demonstrated in 24-48 h supernatants of LB cells in culture and disappeared after 4 days of culture. Inhibitory activity was cytostatic but not cytotoxic and was non-specific since it inhibited the growth of both syngeneic and allogeneic normal and tumour cells. Such activity was found in the 10(5)-1.3 x 10(5) M(r) serum fraction after a Sephacryl S200 chromatography. Though sensitive to protease, trypsin or neuraminidase treatment, which indicated its glycoprotein nature, it remained stable after heating or freezing-thawing cycles as well as after alkaline, acid or hyaluronidase treatment. Addition of exogenous IL-2 abrogated inhibitory activity. ELISA showed the presence of soluble IL-2R both in LB conditioned medium and in above serum fraction. It is demonstrated that the inhibitory factor, soluble IL-2R, is produced by LB leukaemia cells, then secreted into blood and ascitic fluid or released into culture supernatants. Soluble IL-2R exerts inhibitory activity blocking cell proliferation and modulating immune response by binding to free IL-2.

Immunological parameters in peripheral blood of patients with renal cell carcinoma before and after nephrectomy

OBJECTIVE

To determine the effects of nephrectomy on the immune response of patients with renal cell carcinoma (RCC).

PATIENTS AND METHODS

Five patients with RCC were monitored before and over a period of up to 3 months after nephrectomy. The aspects measured were the phenotypic expression of markers on circulating lymphocytes, circulating concentrations of cytokines, markers of inflammatory and immune responses, and natural killer (NK) cell and lymphokine-activated killer (LAK) cell activity in peripheral blood mononuclear cells (PBMC). The suppressive activity of patients' plasma on NK activity and ability to generate interleukin-2 (IL-2) induced LAK cells in PBMC of normal volunteers was also investigated.

RESULTS

The results indicated that high CD4/8 ratios were present pre-nephrectomy with evidence of inflammatory responses and immune activation in some patients, particularly those with metastatic disease.

CONCLUSION

The effect of nephrectomy was to decrease the inflammatory response and increase immune activation. Various defects in NK cell activity and LAK cell generation were demonstrated pre-surgery which slowly improved once the primary tumour had been removed and it is suggested that such defects could have contributed to tumour growth and development due to an ineffective immune response.

Association of IgA-anti-Fab autoantibodies with disease stage in head-and-neck cancer

Patients with head-and-neck cancer commonly have immune defects. It was reported that these patients have raised serum IgA levels. We investigated whether IgA-anti-Fab autoantibodies, which occur in association with immune dysfunction, are present in patients with head-and-neck cancer. Sera of 101 patients with squamous-cell carcinoma (SCCHN) and 8 patients with adenoid cystic carcinoma (ACCHN) of the head and neck were tested in ELISA for IgA-anti-Fab autoantibody activity. IgA-anti-Fab serum activity was significantly higher in both SCCHN and ACCHN patients than in healthy controls. In patients with SCCHN, an association between disease stage and IgA-anti-Fab activity was established. Stage-IV patients had significantly higher IgA-anti-Fab than stage-I patients or healthy controls. Stage-II and stage-III patients had intermediate levels. Extremely high IgA-anti-Fab activity was observed in 7 patients who died within 6 months following testing, suggesting a relationship of autoimmunity with terminal disintegration of physiological body functions. IgA-anti-Fab autoantibodies may explain the occurrence of immune defects in patients with head-and-neck cancer.

Contribution of serum inhibitory factors and immune cellular defects to the depressed cell-mediated immunity in patients with head and neck cancer

The immune system of patients with head and neck cancer is frequently depressed. Serum inhibitory factors and immune cell dysfunction are known contributors to this depression, but their relative roles are unclear. We have examined these factors to determine whether a common pathway is involved. Is the defect an unresponding "switched-off cell" or is it a remedial defect responsive to the removal of serum inhibitory factors and/or to lymphokine restoration? Immune tests were performed in 66 patients with high-stage head and neck cancer. Serum inhibitory factors were measured by incubation of heat-inactivated serum (10%) with phytohemagglutinin (PHA)-stimulated lymphocytes or natural killer (NK) cells using the K562 assay. Lymphokine-activated killer (LAK) cell cytotoxicity was measured (in the presence/absence of serum) using chromium 51-labeled Raji tumor cells cultured 5 days with interleukin-2 (IL-2) (100 or 1,000 U/mL) and/or interferon-alpha (INF-alpha) (100 U/mL). IL-2 receptors, CD25 or p55 (low affinity) and p75 (high affinity), were measured by flow cytometry through fluorescence-activated cell sorter analysis. Serum inhibitory factors were detected in more than 50% of the patients. Head and neck cancer sera significantly inhibiting the normal lymphocyte response to PHA (11 of 22 patients), as well as significantly inhibiting the NK response of normal lymphocytes and the functional expression of the IL-2 receptor. LAK cell function at low-dose IL-2 was depressed in 45% of the patients (9 of 20) and was restored by increased IL-2 (1,000 U/mL) or a combination of IL-2 and INF-alpha. Twenty-five percent of the patients were unresponsive to maximum lymphokine stimulation. Half of the patients had depressed expression of the low-affinity IL-2 receptor (CD25). The cause of immune depression in patients with head and neck cancer is multifactorial and is related to serum inhibitory factors, as well as to inherent cellular defects. Based on these data, we would suggest a therapeutic approach in selected patients that includes the removal of serum inhibitory factors by plasmapheresis and restoration of cellular defects by combined IL-2 with or without INF-alpha.

Inhibition of interleukin-2 dependent immune responses by serum from patients with advanced gastrointestinal cancer

Immunotherapy with high-dose interleukin-2 (IL-2) fails to induce clinical responses in patients with advanced gastrointestinal cancer, but may be effective in patients with malignant melanoma or renal adenocarcinoma. The hypothesis that this failure may be related to immunosuppressive moieties present in patients with advanced gastrointestinal cancer was investigated. Serum samples from 93 patients (32 advanced gastrointestinal cancer, 22 localized gastrointestinal cancer, 13 melanoma/renal adenocarcinoma and 26 age-matched controls) were incubated with peripheral blood lymphocytes from healthy volunteers. The generation of cytolytic lymphokine-activated killer (LAK) cells and the allogeneic mixed lymphocyte response (MLR) were measured in-vitro. LAK effector cytotoxicity (mean % +/- SEM) was significantly (P < 0.05) decreased by serum from advanced gastrointestinal cancer patients (30 +/- 3) compared with that from controls (47 +/- 3), serum from patients with localized gastrointestinal cancer (49 +/- 2) or that from patients with melanoma or renal adenocarcinoma (51 +/- 2). MLR responses were also significantly (P < 0.05) decreased using advanced gastrointestinal cancer patients serum compared to controls. A dose-response phenomenon for suppression of MLR was observed. Serum from patients with melanoma or renal adenocarcinoma was not significantly different to control samples. The immunosuppressive properties of serum from patients with advanced gastrointestinal carcinoma may abrogate therapeutic attempts using IL-2.

Effect of anti-CD3/anti-CD28/interleukin-2 stimulation of mononuclear cells on transforming growth factor beta inhibition of lymphokine-activated killer cell generation

After simultaneous stimulation with anti-CD3 monoclonal antibody (mAb) at 10 ng/ml, anti-CD28 mAb at 125 ng/ml, and interleukin-2 (IL-2) at 20 U/ml, peripheral blood mononuclear cells (PBMC) were partially resistant to immunosuppression by transforming growth factor-beta (TGF beta 2). The doses of TGF beta 2 that inhibit cytotoxicity of IL-2 stimulated cells by 60%-70% were much less effective when the same cells were stimulated with anti-CD3/anti-CD28/IL-2. This favorable stimulation a generated a cell population characterized by high lytic activity, excellent expansion, and a greater resistance to immunosuppressive action of TGF beta 2. The secretion of secondary cytokines important for LAK generation is considered a crucial event, at least partially responsible for the antagonization of TGF beta immunosuppression.

Detection of regulatory factors of lymphokine-activated killer cell activity in head and neck cancer patients treated with interleukin-2 and interferon alpha

Interleukin-2 (IL-2) and interferon-alpha (INF-alpha) are biologic modifiers that have met with limited clinical success in the treatment of human malignancies. We conducted a phase 2 trial of IL-2-IFN-alpha in patients with advanced or unresectable squamous cell carcinoma of the upper aerodigestive tract. Two patients were analyzed sequentially for serum induction phase-blocking factors of lymphokine-activated killer (LAK) cell activity in their therapy. Serum also modulated LAK activity independent of autologous or allogeneic effector cells. Significantly inhibitory serum samples were stable in multiple freezings and thawings. Heat-treating the inhibitory serum, at 56 degrees C for 30 minutes, only partially removed the serum inhibitory capacity. Sequential analysis of p55 and p75, subunits of IL-2 receptors, showed that absence of effector cell lytic activity was associated with markedly decreased fluorescence of the IL-2Rp75 subunit only. No significant alteration of the IL-2Rp55 subunit occurred with therapy. These studies support the theory that lymphocyte and multiple serum factors, developing during IL-2-IFN-alpha therapy, regulate the induction of in vitro LAK activity. Further understanding of these factors may lead to improvements in biologic modifier therapy.