Enhancement of tumorigenicity of human breast adenocarcinoma cells in nude mice by matrigel and fibroblasts.

The failure of MCF7 cells to induce the formation of tumours after sub-cutaneous inoculation into athymic nude mice can be obviated by the simultaneous injection of an extract of basement membrane proteins (matrigel). Tumour growth is promoted and the latency period is low (2 to 4 weeks). In the absence of matrigel, the simultaneous inoculation of fibroblasts and MCF7 cells also resulted in the development of tumours, but with a longer latency period (about 2 months). The tumorigenic synergy between matrigel and fibroblasts was evidenced by co-inoculating MCF7 cells MDA-MB 231 cells with fibroblasts and matrigel. This co-inoculation decreased the delay of appearance of the tumours and/or accelerated the tumour growth, depending upon the number of fibroblasts injected. Repeated injections of fibroblasts conditioned medium, at the site of inoculum of tumour cells also enhanced tumour growth, suggesting the involvement of soluble factors secreted by fibroblasts. Histologically, tumours induced by co-inoculation of tumour cells and fibroblasts contained more stromal structures including vimentin-positive cells, fibronectin and interstitial collagens. These data suggest that human tumours may be reconstituted and grown in athymic nude mice using basement membrane components and fibroblasts as inductors

Cytotoxic Aporphine Alkaloids from Cassytha filiformis L.

info:eu-repo/semantics/nonPublishe

Cytotoxic aporphine alkaloids from Cassytha filiformis L.

Purification of a cytotoxic crude alkaloid extract of Cassytha filiformis led to the isolation of four known aporphine alkaloids: neolitsine, dicentrine, cassythine (= cassyfiline) and actinodaphnine. Their structures were determined by analysis of spectroscopic data. All isolated alkaloids were tested for their cytotoxic activities on cancer and non-cancer cell lines in vitro. Neolitsine was the most active against HeLa and 3T3 cells (IC50 :21.6 μM, and 21.4 μM, respectively). Cassythine and actinodaphnine showed the highest activity against Mel-5 (IC50 :24.3 μM and 25.7 μM, respectively) and HL-60 (IC50 :19.9 μM and 15.4 μM, respectively). This is the first report on the cytotoxic activity of C. filiformis extract and of neolitsine and cassythine. Furthermore, the complete NMR data of cassythine and actinodaphnine are given here for the first time.info:eu-repo/semantics/publishe

Ent-trachyloban-3beta-ol, a new cytotoxic diterpene from Croton zambesicus

The dichloromethane extract of leaves of Croton zambesicus (Euphorbiaceae) showing in vitro cytotoxicity against human cervix carcinoma cells was investigated in order to identify its active compounds. A bio-guided fractionation by HSCCC followed by MPLC led us to isolate a trachylobane diterpene, ent-trachyloban-3β-ol, with cytotoxic properties (IC50 on HeLa cells = 7.3 μg/ml) .This is the first report on the cytotoxicity of a trachylobane diterpene.info:eu-repo/semantics/publishe

Relationships between in vitro lymphoproliferative responses and levels of contaminants in blood of free-ranging adult harbour seals (<i>Phoca vitulina</i>) from the North Sea

In vitro culture of peripheral blood leucocytes (PBLs) is currently used in toxicological studies of marine mammals. However, blood cells of wild individuals are exposed in vivo to environmental contaminants before being isolated and exposed to contaminants in vitro. The aim of this study was to highlight potential relationships between blood contaminant levels and in vitro peripheral blood lymphocyte proliferation in free-ranging adult harbour seals (Phoca vitulina) from the North Sea. Blood samples of 18 individuals were analyzed for trace elements (Fe, Zn, Se, Cu, Hg, Pb, Cd) and persistent organic contaminants and metabolites (SPCBs, SHO-PCBs, SPBDEs, 2-MeO-BDE68 and 6-MeO-BDE47, SDDXs, hexachlorobenzene, oxychlordane, trans-nonachlor, pentachlorophenol and tribromoanisole). The same samples were used to determine the haematology profiles, cell numbers and viability, as well as the in vitro ConA-induced lymphocyte proliferation expressed as a stimulation index (SI). Correlation tests (Bravais-Pearson) and Principal Component Analysis with multiple regression revealed no statistically significant relationship between the lymphocyte SI and the contaminants studied. However, the number of lymphocytes per millilitre of whole blood appeared to be negatively correlated to pentachlorophenol (r = -0.63, p = 0.005). In adult harbour seals, the interindividual variations of in vitro lymphocyte proliferation did not appear to be directly linked to pollutant levels present in the blood, and it is likely that other factors such as age, life history, or physiological parameters have an influence. In a general manner, experiments with in vitro immune cell cultures of wild marine mammals should be designed so as to minimize confounding factors in which case they remain a valuable tool to study pollutant effects in vitro

Effects of L-thiazolidine-4-carboxylic acid (thiaproline) on cancer cells in culture

Three animal and experimental cancer cell lines are cultivated in vitro and treated with thiaproline. At relatively high concentrations, a significant inhibition of mitotic activity is noted, especially when cell population density is high (confluence, superposition). The sensitivity of these cell lines to thiaproline is not identical. No necrosis, no morphological alterations and no mitotic anomalies are noted

Effects of trace metals on mouse B16 melanoma cells in culture

The effects of fourteen metal ions on B16 cell proliferation, differentiation and melanogenesis have been analysed