semaxinib and pyrrolidine-dithiocarbamic-acid

NF-κB and IL-6, a NF-κB downstream mediator, play a central role in the inflammatory response of tissues. We aimed to determine the role of the classical NF-κB pathway in severe pulmonary arterial hypertension (PAH) induced by SU5416 and chronic hypoxia (SuHx) in rats. Tissue samples from patients with idiopathic PAH (iPAH) and control subjects were investigated. SuHx rats were treated from Days 1 to 3, 1 to 21, and 29 to 42 with the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) and/or from Days 1 to 21 with anti-IL-6 antibody. Nuclear staining for NF-κB, an indicator of the activation of the classical NF-κB pathway, was detected in pulmonary arterial lesions of patients with iPAH and SuHx rats. NF-κB inhibition with PDTC prevented and reduced pulmonary arterial obliteration without reducing muscularization. However, the elevated lung levels of IL-6 were not reduced in PDTC-treated SuHx animals. PDTC treatment prevented or reduced apoptosis of pulmonary artery wall cells and pulmonary arterial obliteration. IL-6 inhibition had only a partial effect on apoptosis and obliteration. Pulmonary arterial media wall thickness was not affected by any of these treatments. Preventive and therapeutic PDTC treatment promoted immune regulation by increasing the number of perivascular CD4(+) T cells, in particular regulatory T cells (early treatment), and by reducing the number of perivascular CD8(+) T lymphocytes and CD45RA(+) B lymphocytes. Therapeutic PDTC treatment further preserved right ventricular function in SuHx animals. Inhibition of NF-κB may represent a therapeutic option for pulmonary arterial obliteration via reduced vessel wall cell apoptosis and improved regulation of the immune system.

Topics: Animals; Apoptosis; CD4-Positive T-Lymphocytes; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Hypoxia; Indoles; Inflammation; Interleukin-6; Leukocyte Common Antigens; Lung; NF-kappa B; Pulmonary Artery; Pyrroles; Pyrrolidines; Rats; Signal Transduction; Thiocarbamates; Time Factors

The progression of breast cancer is associated with oxidative stress.  However, the effects of pyrrolidine dithiocarbamate (PDTC), a known antioxidant, on the development of breast cancer are poorly understood.  The present study evaluates the effects of PDTC on tumor growth, the expression of vascular endothelial growth factor (VEGF), and angiogenesis of breast cancer in female mice.  Eight week old female mice (C57BL/6J) were given PDTC at 100 to 200 mg/kg/day for 3 weeks (n=10).  The control mice received regular drinking water only.  In the 2nd wk, 5x10^5 E0771 (mouse breast cancer) cells were injected in the pad of the fourth mammary gland of the mice.  Tumor size was monitored using dial calipers.  At the end of the experiment, the tumors were isolated and measured for tumor size, intratumoral microvessel (IM) density using CD31 immunohistochemistry staining, NFκB activation using EMSA, and VEGF protein levels using ELISA.  PDTC treatment caused a significant decrease in tumor weight compared to the control (0.64±0.22 vs. 1.43±0.31 g; n=8; P< 0.01), and a significant decrease in IM density (66.1±5.3 vs. 84.2±9.4 IM# /mm^2; P< 0.01).  There was a significant decrease in tissue protein levels of VEGF (22.6±2.1 vs. 32.4±2.6 pg/mg) and a 43% reduction NFκB activation in the breast tumors of mice treated with PDTC compared to the control group (P< 0.01).  Western blot indicated that estrogen receptor-α (ERα), VEGF receptor-1 (Flt-1), and VEGF receptor-2 (Flk-1) were expressed in E0771 cells.  VEGF receptor inhibitor SU5416 and PDTC synergistically suppressed the proliferation of E0771 cells.  PDTC also significantly inhibited the migration of cultured E0771 cells.  These results support the hypothesis that PDTC suppresses tumor angiogenesis, growth, and migration of breast cancer via inhibiting autocrine and paracrine effects of VEGF through the reduction of NFκB activation and VEGF expression.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Drug Synergism; Estrogen Receptor alpha; Female; Gene Expression Regulation, Neoplastic; Humans; Indoles; Mice; Mice, Inbred C57BL; Neovascularization, Pathologic; NF-kappa B; Pyrroles; Pyrrolidines; Thiocarbamates; Tumor Burden; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2