A glycoprotein isolated from the sponge, Pachymatisma johnstonii, has anti-leishmanial activity.

A high anti-leishmanial activity was observed in an aqueous extract from the marine sponge Pachymatisma johnstonii, Bowerbank 1842 (Demospongiae, Geodiidae). Pachymatismin, a glycoprotein, was purified and shown to be a cytotoxic agent, which acts on promastigote and clinical-like amastigote stages with IC50 about 1 microg protein/ml and induces changes in the cell shape, phospholipase A2 activity and invasion capacity of the parasite. We believe pachymatismin is the first reported substance from a marine organism with anti-leishmanial activity.

Different microtubule network alterations induced by pachymatismin, a new marine glycoprotein, on two prostatic cell lines.

Pachymatismin is a new cytostatic factor extracted from the marine sponge Pachymatisma johnstonii Bowerbank. To investigate the mechanism of action of pachymatismin, we studied its effects on two human prostate cell lines (DU145 and E4) of tumor origin. Immunocytochemistry demonstrated that the drug caused depolymerization of microtubules in DU145 cells, this effect being similar to that of estramustine, known to be a microtubule-depolymerizing agent. E4 cells, described to be resistant to the microtubule-depolymerizing agent estramustine, were also found resistant to pachymatismin. Pachymatismin at the same dose that destroys microtubule organization in DU145 cells is not able to induce microtubule depolymerization in E4 cells. Compared to the estramustine- and pachymatismin-sensitive DU145 cells, E4 cells revealed an increase of betaI+II, betaIII, betaIV isotypes as well as post-translational modifications of tubulin, such as polyglutamylation and acetylation. In addition, the level of tau protein was also enhanced in E4 cells compared to DU145 cells. The effects of pachymatismin were tested in vitro using calf brain microtubules. It was shown that the drug lowers the capacity of microtubules to reassemble in vitro. Interestingly, pachymatismin has been found to inhibit microtubule assembly less efficiently when the ratio of tau to tubulin is increased. Taken together, pachymastismin has been shown to induce in vivo microtubule depolymerization following binding to microtubule proteins. Changes in microtubule components such as tubulin isoforms or tau may be involved in a decrease of sensitivity to pachymatismin.

Cloning of a human cancer cell line (NSCLC-N6) and comparative study of the clones in vitro.

Non-small-cell lung carcinoma (NSCLC) is a particularly serious disease because of its chemoresistance to current treatments. To investigate the nature of his generally innate resistance, we cloned an established cell line (NSCLC-N6) derived from a non-small cell bronchopulmonary carcinoma. Four cell subpopulations (C15, C65, C92 and C98) were isolated from the mother line. These four clones were studied in comparison with each other for cell doubling time in vitro, ploidy, chemosensitivity in vitro, cytogenetic, expression of the oncogene erb-B2 and other tumor markers (Kr, CEA and Chr A). Each clone shows a distinct biologic pattern for various biological parameters. Our results indicated hat cell doubling time (in vitro) increased when the hyperploid population was prevailing. The clones differ in their chemosensitivity to therapeutic agents. This cellular diversity might help to explain why these tumors are chemoresistant. This heterogeneity within NSCLC tumors should be taken into consideration in the choice of treatment.

In vivo effect of pachymatismin, a new marine glycoprotein, on a human non-small-cell lung carcinoma.

Pachymatismin is a novel glycoprotein extracted from a marine sponge, which has an antiproliferative effect in vitro on cells from a human non-small-cell bronchopulmonary carcinoma (NSCLC-N6). The drug blocks irreversibly the cells in the G0/G1 phase of the cell cycle. Here, we investigate the antitumor activity of pachymatismin against this cell line. Tumor growth was studied after three weeks treatment of nude mice by different doses of pachymatismin. A significant decrease in tumor growth was observed.

Correlation between multidrug resistance and the degree of differentiation of non-small-cell bronchopulmonary carcinoma (NSCLC) in vitro and in vivo.

The correlation between the degree of expression of the multidrug resistance-1 (MDR-1) gene and the process of differentiation into non-small-cell, bronchopulmonary carcinoma was studied in vitro and in vivo. For this purpose, a technique for the quantitative analysis of MDR-1 gene expression was developed by competitive reverse-transcriptase polymerase chain reaction. The study of 9 epidermoid carcinomas with various degrees of differentiation did not enable us to establish a correlation in vivo in the patient. However, an in vitro study performed on a non-small-cell lung carcinoma cell line and two of its clones showed that MDR-1 gene expression increased with the degree of differentiation, which was confirmed in vivo when this line was xenografted into nude mice.

Effects in vitro of pachymatismin, a glycoprotein from the marine sponge Pachymatisma johnstonii, on a non-small-cell bronchopulmonary carcinoma line (NSCLC-N6).

Pachymatismin is a new cytostatic factor extracted from the marine sponge Pachymatisma johnstonii Bowerbank 1842 (Demospongiae, Geodiidae), which has an antiproliferative effect in vitro on cells from a human non-small-cell bronchopulmonary carcinoma (NSCLC-N6). The substance, both administered as a continuous and discontinuous treatment, triggers the irreversible arrest of cells in the G0/G1 phase of the cell cycle and morphological changes, thereby causing their destruction. Taken all together, these observations suggest that pachymatismin would induce atypical terminal cellular differentiation.

Pachymatisma johnstonii extract opens ATP-sensitive potassium channels in cardiac myocytes of the frog heart.

The effects of a proteic extract (PachyTX), isolated from the sponge Pachymatisma johnstonii, were studied respectively with intracellular microelectrode and the "whole cell" patch clamp techniques on fibers and myocytes isolated from the sinoatrial region of frog heart. PachyTX significantly and reversibly shortened the action potential duration and decreased the stimulated peak contraction. Under voltage clamp, PachyTX increased, in a dose-dependent manner, a tetraethylammonium-insensitive but glibenclamide-inhibited outward current. This current failed to develop when adenosine 5'-triphosphate (ATP) was intracellularly applied to the cell by diffusion through the patch electrode. PachyTX mimics the effect of the ATP-sensitive K channel opener SR 44866 on frog atrial action potential and peak contraction. From this evidence, it can be concluded that PachyTX is a new natural potent opener of ATP-sensitive K channels in frog atrial heart muscle and that the opening of these channels is associated with the inhibition of the contraction of cardiac muscle.

Cytotoxicity and hemolysis by an extract of the sponge Pachymatisma johnstonii.

In vitro cytotoxicity on human rhinopharynx KB cells, as well as hemolytic activity on human erythrocytes, was produced by an aqueous extract of the sponge Pachymatisma johnstonii. Optimum temperature and pH were the same for both activities (37 degrees C, pH 5). Moreover, after partial purification, the compounds involved were found in the same chromatographic fraction. These compounds were sensitive to treatment with dithiothreitol, but not with papain or trypsin. Cytotoxicity was destroyed by heat, whereas hemolysis subsisted after the extract was heated to 100 degrees C.

[Study of adenine mononucleotides of the adductor muscle of the oyster by fractionation on a PEI cellulose column]. / Etude des mononucléotides adényliques du muscle adducteur de l'huître par fractionnement sur colonne de cellulose PEI

Adenine mononucleotides of transulucent and white parts in the adductor muscle of Japanese oyster are identified and measured after the separation on PEI-cellulose column. The studies are performed on oysters kept in aerated sea water aquarium. Results obtained for both tissues are compared each other and with the literature data.