Glucosamine induces activated T cell apoptosis through reduced T cell receptor

Glucosamine (GlcN), like N-acetylglucosamine (GlcNAc), is salvaged into the hexosamine pathway and is converted to UDP-GlcNAc. Golgi N-glycan branching enzymes produce N-glycans, using UDP-GlcNAc as a substrate, which attach to the T cell receptor (TCR) and cytotoxic T-lymphocyte antigen-4 (CTLA-4). These findings suggest that GlcN exerts the immunoregulation through TCR signalling, which could be involved not only in cytokine production but also activated T cell apoptosis. In fact, a preliminary study showed that GlcN reduced the number of CD3+ T cells of NC/Nga mice with AD-like skin lesions. Therefore, whether apoptosis of T cells would be one of the potential molecular mechanisms of GlcN-induced immunosuppression was investigated. Cultured human primary along with Jurkat T cells and purified T cells from NC/Nga mice with or without Df-induced AD-like skin lesion were used for the study. Glucosamine treatment increased the number of T cells expressing β1,6GlcNAc-branched N-glycans, with reduced ZAP-70 phosphorylation and enhanced CTLA-4 expression. Glucosamine treatment reduced the number of activated T cells from both the human primary and Jurkat cells and the dermatitis-induced mice. The expression of FasL and activated caspases, particularly caspase-3, was increased, whereas the phosphorylation of PI3K, Akt and NF-κB was decreased by GlcN treatment. Therefore, in addition to down-regulating TCR signalling and promoting CTLA-4 expression, GlcN may also suppress T cell function by enhancing apoptosis of activated T cells, through both extrinsic and intrinsic apoptotic signalling pathways, which were regulated by the inhibition of PI3K/Akt and NF-κB phosphorylation.

Glucosamine improved atopic dermatitis-like skin lesions in NC/Nga mice by inhibition of Th2 cell development

Dysregulated Th subset responses, characterized by Th2-dominant allergic inflammation, are thought to be central to the pathogenesis of atopic dermatitis (AD). Glucosamine has been shown to have immunosuppressive properties, but its effect on AD has not been examined. In this study, the immunoregulatory effects of glucosamine, using dermatophagoides farinae (Df)-induced AD-like skin lesions in NC/Nga mice, were investigated. The clinical scores were reduced significantly by the treatment with glucosamine at 10 and 20 mg/day. Histological analysis of the skin also revealed that treatment of glucosamine at 10 and 20 mg/day significantly reduced the inflammatory cellular infiltrate, including mast cells and eosinophils. The levels of serum IgE and Th2 cytokines in spleen cells were reduced, whereas no significant change was detected in IFN-γ, a Th1 cytokine. To determine the mechanism associated with inhibition of the Th2 immune response, the effects of glucosamine on the selective differentiation pathway of the Th subset in vitro was examined in NC/Nga mice. The results showed that glucosamine suppressed the differentiation of naïve CD4(+) T cells to Th2 cells in vitro. On the basis of in vivo and in vitro results of the NC/Nga mice, the immunobiological effects of glucosamine on peripheral blood mononuclear cells from patients with AD were examined. The production of Th2 cytokines, such as IL-4 and IL-5, was significantly decreased after in vitro administration of glucosamine, which suggest that glucosamine might be a useful immunomodulatory agent for the treatment of human AD.

Adjuvant chemotherapy in non-small cell lung cancer

Adjuvant chemotherapy is considered a standard of care for many malignancies, the most well known being breast and colon cancer. Unfortunately, less than a third of patients with non-small cell lung cancer (NSCLC) present with resectable disease and despite resection outcomes are often poor with a median 5-year survival of 40-50%. Modern chemotherapy for NSCLC provides both a survival advantage and an improvement in quality of life in the palliative setting. Several large studies using modern platinum-based regimens have been presented since the 1995 meta-analysis. This demonstrated a nonsignificant benefit for older platinum-based regiments. These studies have consistently shown a survival benefit across all stages of resection with acceptable toxicity. The absolute magnitude of benefit is consistent with that achieved in other malignancies where adjuvant chemotherapy is offered as a standard of care.

The management of PS2 patients with advanced non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths in the Western world. Patients with impaired performance status (PS2 or greater) have both worse prognosis and toxicity from treatment in general. The median survival of PS2 patients with advanced NSCLC is 4-5 months in comparison with the 8-9 months expected for those with good performance status (PS0-1). PS2 represents 30%-40% of all patients with advanced NSCLC, and their management remains controversial. In general, they have been excluded from most clinical trials. The emphasis on treatment should be on maintenance and improvement of quality of life with treatment strategies that provide rapid clinical improvement.

Gemcitabine and oxaliplatin followed by paclitaxel and carboplatin as first line therapy for patients with suboptimally debulked, advanced epithelial ovarian cancer. A phase II trial of sequential doublets. The GO-First Study

OBJECTIVES

Gemcitabine and oxaliplatin are active in epithelial ovarian cancer with minimal overlapping toxicity. We studied the efficacy and toxicity of this combination in patients with advanced ovarian cancer when given prior to carboplatin and paclitaxel.

METHODS

Chemonaive patients with epithelial ovarian cancer and measurable disease were eligible for the study. Treatment consisted of gemcitabine 1250 mg/m2 on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8 every 21 days (GO) for 4 cycles. This was followed by carboplatin AUC = 6 and paclitaxel 175 mg/m2 on day 1 every 21 days (CP) for 4 cycles.

RESULTS

Twenty patients, median age 62 years (range 39-78), FIGO stages III (16) and IV (4) received treatment. The response rate (RR) after 4 cycles of GO was 80% (95%CI 61-99%) (4 complete responses (CR), 12 partial responses (PR)). Interval debulking surgery was performed in 7 patients (35%). After CP chemotherapy, RR increased to 85% (95%CI 68-100%) (CR = 13, PR = 4). Median time to progression was 14.5 months. Estimated median overall survival was 31.5 months. Toxicities of GO were mild; grade 3/4 nausea in 3 patients (15%) and vomiting in 2 patients (10%), grade 3/4 neutropenia in 5 patients (25%). Grade 2/3 peripheral neuropathy occurred in 5 patients (25%). After sequential administration of CP, grade 2/3 neuropathy occurred in 13 patients (72%).

CONCLUSION

The sequential doublet regimen of GO followed by CP resulted in unacceptable neurotoxicity and is not recommended for further study; however, the doublet gemcitabine and oxaliplatin has significant activity in the first line treatment of patients with ovarian cancer.

Management of the elderly patient with advanced non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most lethal of the common solid malignancies. It is predominantly a disease of the elderly with the median age at diagnosis 68 years. Unfortunately, the majority of patients present with advanced disease whereby palliation is the primary aim of treatment. The elderly have a long history of undertreatment and non-inclusion in clinical trials with regard to cancer. Elderly-specific studies demonstrate that chemotherapy provides both a survival and quality-of-life benefit in advanced NSCLC. Increasing emphasis is placed on the objective assessment of fitness for chemotherapy and the integration of molecularly targeted agents into treatment paradigms.

Dissociation/association properties of a dodecameric cyclomaltodextrinase. Effects of pH and salt concentration on the oligomeric state

As an effort to elucidate the quaternary structure of cyclomaltodextrinase I-5 (CDase I-5) as a function of pH and salt concentration, the dissociation/association processes of the enzyme were investigated under various pH and salt conditions. Previous crystallographic analysis of CDase I-5 indicated that it existed exclusively as a dodecamer at pH 7.0, forming an assembly of six 3D domain-swapped dimeric subunits. In the present study, analytical ultracentrifugation analysis suggested that CDase I-5 was present as a dimer in the pH range of 5.0-6.0, while the dodecameric form was predominant at pH values above 6.5. No dissociation of the dodecamer was observed at pH 7.0 and the above. Gel filtration chromatography showed that CDase I-5 dissociated into dimers at a rate of 8.58 x 10(-2) h(-1) at pH 6.0. A mutant enzyme with three histidine residues (H49, H89, and H539) substituted with valines dissociated into dimers faster than the wild-type enzyme at both pH 6.0 and 7.0. The tertiary structure indicated that the effect of pH on dissociation of the oligomer was mainly due to the protonation of H539. Unlike the pH-dependent process, the dissociation of wild-type CDase I-5 proceeded very fast at pH 7.0 in the presence of 0.2-1.0 M of KCl. Stopped-flow spectrophotometric analysis at various concentrations of KCl showed that the rate constants of dissociation (kd) from dodecamers into dimers were 5.96 s(-1) and 7.99 s(-1) in the presence of 0.2 M and 1.0 M of KCl, respectively.