Serum levels of tumor necrosis factor in squamous cell carcinoma of the head and neck

Sheddase activity of tumor necrosis factor-alpha converting enzyme is increased and prognostically valuable in head and neck cancer

Tumor necrosis factor alpha converting enzyme (TACE) is a sheddase overexpressed in cancers that generates cancer cell growth and survival factors, and is implicated in carcinogenesis and tumor growth. This indicates that TACE could be a potentially important cancer biomarker. Unexpectedly, TACE expression in cancer tissues does not correlate with cancer stage or invasiveness. Although TACE sheddase activity is a more direct and potentially better indicator of TACE biology and might be a better cancer biomarker than TACE expression, it has not been studied in cancer tissues. In the present study, we developed a reliable specific assay for quantification of TACE sheddase activity, investigated TACE activity and TACE protein expression in head and neck cancer (HNC) tissues, and examined the correlation of the results with HNC clinical stages and likelihood to recur. We found that HNC cell lines and tissues contained remarkably higher quantities of TACE activity and TACE protein than normal keratinocytes or oral mucosa. siRNA silencing of TACE resulted in the inhibition of release of the tumorogenic factors amphiregulin and transforming growth factor alpha, and tumor protective factors tumor necrosis factor receptors from HNC cells. Importantly, TACE activity, but not TACE protein expression, was significantly higher in large, T3/T4, primary tumors relative to small, T1/T2, primary tumors, and especially in primary tumors likely to recur relative to those unlikely to recur. These data show that increased TACE activity in cancer is biologically and clinically relevant, and indicate that TACE activity could be a significant biomarker of cancer prognosis.

Reactive oxygen species production by blood neutrophils of patients with laryngeal carcinoma and antioxidative enzyme activity in their blood

Squamous cell carcinoma of the head and neck is a devastating illness with a severe impact on affected individuals. Several mechanisms may lead to oxidative stress in tumor-bearing patients, among others chronic inflammation. Inflammatory cells, especially macrophages and neutrophil leukocytes, may produce reactive oxygen species (ROS) which participate in carcinogenesis and tumor-associated immunosuppression. The aim of the study presented in this paper was to compare the production of reactive oxygen species (ROS)--superoxide anion (O2-) and hydrogen peroxide (H2O2)--by neutrophils isolated from the blood of 16 patients with larynx carcinoma and 15 healthy controls. The serum activity of superoxide dismutase and catalase as well as the total peroxidase activity in serum have also been estimated. The production of ROS, especially spontaneous and phorbol 12-myristate 13-acetate (PMA)-induced O2-, was relatively higher in the patients with larynx carcinoma than in the healthy controls and increased parallel with the tumor stage (tumor, node, metastasis-TNM staging). The serum activity of catalase and peroxidase was also highest in the patients with stage T3 and T4 larynx carcinoma. After partial or total laryngectomy, a significant decrease in ROS production and the serum activity of catalase and peroxidase was observed. In contrast, the serum level of superoxide dismutase, which had been low prior to surgery, especially in the patients with advanced tumor stages (T3-T4), increased significantly afterwards. The results indicate the existence of oxidative stress in the blood of patients with larynx carcinoma and its significant decrease after partial or total laryngectomy.

Is insulin an antiinflammatory molecule?

I suggest that insulin suppresses the secretion and antagonizes the harmful effects of tumor necrosis factor-alpha, macrophage migration-inhibitory factor, and superoxide anion. Therefore, the glucose-insulin-potassium regimen might be beneficial in acute myocardial infarction and useful in the management of patients with septicemia, septic shock, and other inflammatory diseases in which tumor necrosis factor-alpha and macrophage migration-inhibitory factor have important roles.

Inhibition of transcription factor nuclear factor-kappaB by a mutant inhibitor-kappaBalpha attenuates resistance of human head and neck squamous cell carcinoma to TNF-alpha caspase-mediated cell death

Tumour necrosis factor-alpha (TNF-alpha) is a cytokine that can induce cell death of different cancers via a cellular cascade of proteases, the caspases. However, TNF-alpha has been detected in tumour and serum of patients with head and neck squamous cell carcinoma (HNSCC), and tumour cell lines derived from this environment often exhibit resistance to TNF-alpha-induced cell death. Cell death mediated by TNF-alpha and caspases may be inhibited by cytoprotective genes regulated by transcription factor nuclear factor-kappaB (NF-kappaB). We recently showed that NF-kappaB is constitutively activated in HNSCC, and that inhibition of NF-kappaB by expression of a nondegradable mutant inhibitor of NF-kappaB, IkappaBalphaM, markedly decreased survival and growth of HNSCC cells in vivo. In the present study, we examined the TNF-alpha sensitivity and response of HNSCC with constitutively active NF-kappaB, and of HNSCC cells in which NF-kappaB is inhibited by stable expression of a dominant negative mutant inhibitor, IkappaBalphaM. Human lines UM-SCC-9, 11B and 38, previously shown to exhibit constitutive activation of NF-kappaB, were found to be highly resistant to growth inhibition by up to 10(4)U/ml of TNF-alpha in 5 day MTT assay. These TNF-alpha resistant HNSCC lines expressed TNF receptor I, and exhibited constitutive and TNF-alpha-inducible activation of NF-kappaB as demonstrated by nuclear localization of NF-kappaB p65 by immunohistochemistry. UM-SCC-9 I11 cells which stably expressed an inhibitor of NF-kappaB, IkappaBalpham, were susceptible to TNF-alpha-induced growth inhibition. DNA cell cycle analysis revealed that TNF-alpha induced growth inhibition was associated with accumulation of cells with sub-G0/G1 DNA content. Cell death was demonstrated by trypan blue staining, and was blocked by caspase inhibitor. We conclude that HNSCC that exhibit constitutive and TNF-alpha-inducible activation of transcription factor NF-kappaB are resistant to TNF-alpha, and that inhibition of NF-kappaB sensitizes HNSCC to TNF-alpha caspase-mediated cytotoxicity. The demonstration of the role of activation of NF-kappaB in resistance of HNSCC to TNF-alpha may be helpful in the identification of potential targets for pharmacological, molecular and immune therapy of HNSCC.

Angiogenesis in the development of head and neck cancer and its inhibition by chemopreventive agents

Squamous cell carcinoma is an aggressive malignancy that often develops as multiple independent lesions throughout the mucosa of the upper aerodigestive tract. Therefore, the comprehensive treatment of this disease must not only address the initial primary neoplasm, but also prevent the progression of the premalignant lesions lurking throughout the rest of the mucosal surfaces. The need to treat these lesions has resulted in a search for chemopreventive agents that can halt or even reverse their malignant progression. The biologic and molecular mechanisms by which most chemopreventive agents act have remained unclear and controversial. Recent work from several laboratories has demonstrated that some drugs may act in part by inhibiting the ability of tumors to induce blood vessel growth. Angiogenesis, the growth of new blood vessels from pre-existing ones, is absolutely required for solid neoplasms to grow beyond 2-3 mm in diameter. Therefore, chemopreventive agents that act to inhibit angiogenesis may provide a very powerful modality by which one may limit the growth of both pre-malignant lesions and small nests of tumor cells. This review will outline the basic changes that occur in tumor cells that result in the switch from an anti-angiogenic to an angiogenic phenotype. In addition, it will discuss the mechanisms by which some chemopreventive agents, presently under clinical investigation, inhibit tumor angiogenesis. Finally, this paper will present a rationale for the use of multiple anti-angiogenic agents as a means of developing new chemopreventive protocols that result in reduced patient toxicity while maintaining similar clinical efficacies.

The immunopharmacology of head and neck cancer: an update

Patients with head and neck squamous cell cancer have cell-mediated immune defects and anergy, which progress with disease. T-lymphocytopenia and dysfunction, monocyte dysfunction, prostaglandins, antigen-antibody complexes, serum and cell suppressive factors, radiation therapy and poor nutrition with zinc deficiency all contribute. Nevertheless, cell-mediated immunoreactivity to tumor is manifest in the majority of the patient's blood and regional nodes, and in the tumor itself by tumor-infiltrating lymphocytes. Lymphocytes from these sources cloned in the presence of interleukin-2 +/- tumor extracts show relatively specific cytotoxicity against squamous cell cancer. Humoral immunity is intact, and increased IgA and IgE levels and antibodies reactive to tumor antigens are common. Tumor-associated antigens detected in serum and tumor include carcinoembryonic antigen, tumor polypeptide antigen, squamous cell cancer antigens, tumor antigen-4 and various mucin antigens. The mucin antigens, in particular, can elicit T-cell responses. Humoral reactivity to such antigens is manifest in circulating immune complexes and immunoglobulin coating of tumor surfaces. Immunotherapeutic efforts in head and neck squamous cell cancer should logically employ T-cell adjuvants, contrasuppression and immunorestoration. Non-specific stimulation with bacille Calmette-Guerin (BCG), levamisole and other agents has not been successful. Encouraging results have been observed in limited trials with indomethacin and plasmapheresis. Early trials with local administration of low dosages of interferon-alpha, natural interleukin-2 and a natural interleukin mixture have produced partial and complete regressions with no toxicity and with intense leukocyte infiltration indicating cellular immunity. Efforts are needed to define the mechanisms and the antigens involved in these reactions. On the contrary, treatments with high dosages of recombinant interferon-alpha and interleukin-2 have yielded few responses and considerable toxicity. Combination strategies are discussed which may improve upon these initial immunotherapeutic effects of these low dose trials.