The Combination of TRAIL Treatment and Cancer Cell Selective Expression of TRAIL-Death Receptor DR4 Induces Cell Death in TRAIL-Resistant Cancer Cells

The human telomerase reverse transcriptase (hTERT) promoter can be used for the tumor-specific expression of transgenes in order to induce selective cancer cell death. The hTERT core promoter is active in cancer cells but not in normal cells. To examine whether the combination of TNF-related apoptosis inducing ligand (TRAIL) treatment and cancer cell-selective expression of the TRAIL-death receptor could induce cell death in TRAIL-resistant cancer cells, we generated a death receptor-4 (DR4)-expressing adenovirus (Ad-hTERT-DR4), in which the expression of DR4 is driven by the hTERT promoter. Upon infection, DR4 expression was slightly increased in cancer cell lines, and cell death was observed in TRAIL-resistant cancer cell lines but not in normal human cells when DR4 infection was combined with TRAIL treatment. We also generated an adenovirus that expresses a secretable isoleucine zipper (ILZ)-fused, extracellular portion of TRAIL (Ad-ILZ-TRAIL). In cells infected with Ad-ILZ-TRAIL, TRAIL was expressed, secreted, oligomerized and biologically active in the induction of apoptosis in TRAIL-sensitive cancer cells. When Ad-hTERT-DR4 infected TRAIL-resistant HCE4 cells and Ad-ILZ-TRAIL infected TRAIL-resistant HCE7 cells were co-cultured, cell deaths were evident 24 h after co-culture. Taken together, our results reveal that the combination of TRAIL and cancer cell-specific expression of DR4 has the potential to overcome the resistance of cancer cells to TRAIL without inducing significant cell death in normal cells.

An antioxidant modulates expression of receptor activator of NF-kappaB in asthma

Oxidative stress plays critical roles in airway inflammation that is usually accompanied by increased vascular permeability and plasma exudation. VEGF increases vascular permeability and leads to airway inflammation. In addition, VEGF has been shown to enhance receptor activator of NF-kappaB (RANK) expression in endothelial cells. An aim of the study was to determine the potential role of antioxidant in the regulation of RANK expression in murine model of asthma. We have used a C57BL/6 mouse model of allergic asthma to evaluate the effect of L-2-oxothiazolidine-4-carboxylic acid (OTC), a prodrug of cysteine, which acts as an antioxidant, and VEGF receptor inhibitor on RANK mRNA expression. The mice develop the following pathophysiological features of asthma in the lungs: increased expression of RANK mRNA, increased number of inflammatory cells of the airways, increased vascular permeability, and increased levels of VEGF. Administration of OTC and VEGF receptor inhibitor markedly reduced plasma extravasation and VEGF levels in allergen-induced asthmatic lungs. We also showed that the increased RANK mRNA expression at 72 h after ovalbumin inhalation were reduced by the administration of OTC or VEGF receptor inhibitor. The results indicate that OTC and VEGF receptor inhibitor which inhibit up-regulation of VEGF expression modulate RANK expression that may be in association with the regulation of vascular permeability, and suggest that VEGF may regulate the RANK expression. These findings provide a crucial molecular mechanism for the potential use of antioxidants to prevent and/or treat asthma and other airway inflammatory disorders.

TNFR2 gene polymorphism in coronary artery disease.

BACKGROUND: Recently atherosclerosis and coronary artery disease (CAD) are considered to be inflammatory diseases. The genetic polymorphism in inflammatory markers has been well studied and found to be associated with development of CAD. AIM: To study the association of biallelic polymorphism at position 196 in exon 6 of tumor necrosis factor 2 (TNFR2) gene and coronary artery disease. SETTINGS AND DESIGN: The study design was a prospective case control study conducted at a tertiary referral center mainly catering to the north Indian population. MATERIALS AND METHODS: One hundred and fifty angiographically proven patients with coronary artery disease and one hundred and fifty age matched controls were genotyped for TNFR2 gene by polymerase chain reaction followed by analysis of restriction fragment length polymorphism. STATISTICAL ANALYSIS: Genotype frequencies were compared in patients and controls by Chi-square test. Binary logistic regression analysis was used to examine the relationship between genotypes and disease, incorporating other variables into the model. RESULTS: The incidence of CAD in those with MM genotype was 65% and in those with RM genotype was 42%. Genotype frequency shows significant association of MM genotype with development of CAD (P < 0.001; odds ratio-2.585; 95% confidence interval 1.533-4.359). The association of TNFR2 genotype with CAD persisted on logistic regression analysis. CONCLUSION: MM genotype of TNFR2 gene is associated with development of CAD and RM genotype appears to be protective.

In vivo ligation of glucocorticoid-induced TNF receptor enhances the T-cell immunity to herpes simplex virus type 1

GITR (glucocorticoid-induced TNF receptor) is a recently identified member of the TNF receptor superfamily. The receptor is preferentially expressed on CD4+CD25+ regulatory T cells and GITR signals break the suppressive activity of the subset. In this study, we wanted to reveal the in vivo function of GITR in herpes simplex virus type 1 (HSV-1) infection. A single injection of anti-GITR mAb (DTA-1) immediately after viral infection significantly increased the number of CD4+ and CD8+ T cells expressing CD25, an activation surface marker, and secreting IFN-gamma. We confirmed these in vivo observations by showing ex vivo that re-stimulation of CD4+ or CD8+ T cells with a CD4+ or CD8+ T-cell-specific HSV-1 peptide, respectively, induced a significant elevation in cell proliferation and in IFN-gamma secretion. Our results indicate that GITR signals play a critical role in the T-cell immunity to HSV-1.

Constitutive expression of 4-1BB on T cells enhances CD4+ T cell responses

4-1BB, a transmembrane molecule, member of the tumor necrosis factor receptor superfamily, is an important costimulatory molecule in the immune response, plays a key role in the clonal expansion and survival of CD8(+)T cells. In this study, we investigated 4-1BB regulation of CD4(+)T cell responses using 4-1BB transgenic (TG) mice that constitutively expressed 4-1BB on mature T cells. We first showed that CD4(+)T cells of 4-1BB TG mice had more sustained proliferative capacity in response to TCR/4-1BB stimulation in vitro compared to WT mice. Secondly, 4-1BB TG mice exhibited a more elevated contact hypersensitivity (CHS) response mediated by CD4+ Th1 cells due to more vigorous expansion of and apoptotic inhibition of CD4(+)T cells. Finally, CD4(+)T cells of 4-1BB TG mice had a heightened capacity for T cell priming. Overall, our results demonstrate the involvement of 4-1BB in CD4(+)Th1 cell responses by regulating the clonal expansion and survival of CD4(+)T cells as seen in CD8(+)T cells.