Tumour cell uptake G2-M accumulation and cytotoxicity of NAMI-A on TS/A adenocarcinoma cells.

The ruthenium(III) complex imidazolium trans-imidazoledimethylsulfoxide-tetrachlororuthenate (NAMI-A) was tested on TS/A adenocarcinoma cells to evaluate the relationship between cell uptake, cell cycle arrest and cytotoxicity. The in vitro challenge of TS/A cells with 10(-4) M NAMI-A for 15 minutes to 4 hours showed a partial reduction of cell growth only after 4 hour exposure. In the same experimental conditions NAMI-A caused the increase of cells in G2-M cell cycle phase directly proportional on the length of treatment, and the ruthenium uptake by tumour cells, measured by flameless atomic absorption spectroscopy, that increases up to 2 hours of treatment and then reaches a plateau. The arrest of cell cycle in the pre-mitotic G2-M phase was transient and completely reversed by 48 hours after treatment. This study showed that the effect of NAMI-A on the cell cycle of TS/A cells is not strictly related to NAMI-A uptake as is the effect on tumour cell proliferation.

Increase of tumour infiltrating lymphocytes in mice treated with antimetastatic doses of NAMI-A.

NAMI-A is a novel antitumour agent, based on ruthenium, which has proved effectiveness against lung metastases of solid mouse tumours. The study focuses on the effects of NAMI-A on leukocyte infiltration into the primary tumour of MCa mammary carcinoma, implanted subcutaneously (s.c.) or intramuscularly (i.m.) into CBA mice. NAMI-A, given with a cycle of daily treatments for six consecutive days on advanced tumours at 35 mg/kg/day, markedly reduces lung metastasis independently of the tumour type (Lewis lung carcinoma, MCa mammary carcinoma or TS/A adenocarcinoma) being treated and of the site of tumour implantation (s.c. or i.m.). The analysis of leukocyte infiltration of the primary tumour, performed on a single cell suspension of cells isolated from a Ficoll gradient on which a raw suspension of primary tumour cells was layered, showed NAMI-A to significantly increase tumour infiltrating lymphocytes. These lymphocytes are almost all CD3+ cells with a significant increase of the CD8+ over the CD4+ subpopulation that reduces the helper/suppressor ratio from 2.8 to 2.1. These data indicated the absence of toxicity of NAMI-A for tumour infiltrating lymphocytes and suggested that this compound might even synergize in combined treatments with cancer immunotherapy.

In vitro growth of TS/A adenocarcinoma and of the gene transfected TS/A-IL4 line on biological substrates.

The growth capacity and adaptation of TS/A and TS/A-IL4 lines on laminin, fibronectin, collagens I and IV and matrigel compared to plastics were studied by flow cytometry. On plastic plates, TS/A-IL4 grows in vitro more slowly than the TS/A line and shows a more differentiated phenotype. TS/A-IL4 cells loose the capacity to bind lymphocytes and peroxidase positive cells obtained from mice implanted with the same tumour. The ratio between fibroblast- and epithelial-like cells of TS/A adenocarcinoma is subjected to marked modifications depending on the substrate on which the two cell lines are grown. IL4 release per cell unit is increased by collagen I as is the number of CD54 positive cells, suggesting that, at least in part, the in vivo rejection of TS/A-IL4 tumor might be ascribed to the stimulatory effect of the tissue on the IL4 release by tumor cells. The overall result is that gene modified TS/A-IL4 line shows marked changes of behaviour, most of them depending on the substrate on which tumor cells are growing.

Human neutrophils specifically interact with human monocyte-derived macrophage monolayers.

Neutrophils and macrophages express on their membrane molecules which may, in principle, interact with each other, promote specific cell to cell adhesion, affect cell function and finally, as a consequence, modulate the progression of the inflammatory process. We tested therefore if human neutrophils specifically adhere to human monocyte-derived macrophage monolayer (MDMM). Our findings show that neutrophils significantly adhere to 4-day old MDMM and that the extent of adhesion is increased by LPS-activation of MDMM. The specificity of the interaction was shown by the very low extent of adhesion of neutrophils either to freshly prepared monocyte or other types of cell monolayers and by the low percent of adhesion showed by eosinophils exposed to 7-day old MDMM. A role for beta2 integrins, CD31 and PAF-receptor in the mechanism of neutrophil-MDMM interaction is suggested by specific antagonists. We suggest that the adhesion between the two cell types could lead to an increase in concentration of neutrophil- or macrophage released factors in the interaction site and in a mutual modulation of phagocyte functions.

A role for eosinophils in the pathogenesis of skin lesions in patients with food-sensitive atopic dermatitis.

BACKGROUND: Atopic dermatitis is associated with skin and blood eosinophilia, but the role of eosinophils in the pathogenesis of the skin lesions is poorly understood. METHODS: To determine whether eosinophils play a role in the pathogenesis of the skin lesions in atopic dermatitis, we studied the relationship between the severity of the disease and both the number and the extent of activation of eosinophils in 15 patients with food-sensitive atopic dermatitis. Furthermore, this relationship was re-evaluated in eight of these patients who, after a period of elemental diet or total parenteral nutrition, showed significant clinical improvement. RESULTS: A clear relationship was found between the number of light-density eosinophils and the severity of the disease both during the active disease and after clinical improvement. Furthermore, we describe an adhesion-stimulating activity for eosinophils in patients' plasma, which does not change after recovery. CONCLUSIONS: Taken together, these observations strongly indicate that eosinophils play a pivotal role in the pathogenesis of the skin lesions in atopic dermatitis. In particular, the light-density phenotype seems to be an essential feature of eosinophils involved in this process. The adhesion-promoting activity that we observed in the patients' plasma could be important in the recruitment of eosinophils from the blood into the skin.