Effects in vitro of sulfated polysaccharide from Schizymenia dubyi (Rhodophyta, Gigartinales) on a non-small-cell bronchopulmonary carcinoma line (NSCLC-N6).

An unusual sulfated heteropolysaccharide containing uronic acids, previously isolated from the red alga Schizymenia dubyi, was studied in vitro for its effect on asynchronous cells of a human non-small-cell-bronchopulmonary carcinoma line (NSCLC-N6). Cell growth appeared to be inhibited in the G1 phase of the cell cycle, and kinetic studies in pretreated cells showed that this growth arrest was irreversible. These events are related to a terminal maturation induction.

Effects of bistramide A on a non-small-cell bronchial carcinoma line.

The antiproliferative effects of bistramide A, a nitrogenous dilactam polyether from Lissoclinum bistratum Sluiter (Urochordata), were studied at the level of the cell cycle in asynchronous cells of the NSCLCN6-L16 line. Bistramide A has a dual mechanism that induces blockade in the G1 phase (compatible with differentiation properties reported elsewhere) and causes polyploidy that is suggestive of inaptitude for cytokinesis. These effects confirm the results of cytomorphology studies in electron microscopy.

Effects of temperature on polyunsaturation in cytostatic lipids of Haslea ostrearia.

Unusual chemicals produced by the-'blue oyster' diatom, Haslea ostrearia, include the water-soluble blue pigment marennine and numerous polyunsaturated sesterterpene oils or haslenes. Aqueous extracts of the alga exhibit in vitro and in vivo activities against human lung cancer cells and anti-HIV effects. Here we report that three haslenes also demonstrate in vitro cytostatic action against a human lung cancer cell line. The most active haslene is the most unsaturated and unsaturation in the haslenes increases with increasing algal growth temperature.

Short-time cytotoxicity of mussel extracts: a new bioassay for okadaic acid detection.

Okadaic acid (OA), the main toxin responsible for diarrhoeic shellfish poisoning (DSP) has high cytotoxicity for KB cell cultures (apparent after 3 hr of contact), facilitating rapid detection in contaminated mussels. We developed a method to determine the minimal active concentration (MAC) based on direct microscopic study of toxin-induced changes in cell morphology. A high correlation was found between the MAC of tested extracts and corresponding OA concentrations in mussel hepatopancreas as measured by high performance liquid chromatography. This technique is rapid and reproducible and does not require the use of living animals.

Bistramide A, a new toxin from the urochordata Lissoclinum bistratum Sluiter: isolation and preliminary characterization.

Two cases of human intoxication caused by the lyophilized powder of Lissoclinum bistratum Sluiter, a New Caledonian ascidian, are reported. The symptoms observed were caused by a substance designated bistramide A (C40H68N2O8) of hitherto unknown chemical structure. Preliminary toxicological investigations indicate that bistramide A may effect the central nervous system, leading to paresthesia and loss of muscle tone. A progressive decrease in cardiac rhythm was also observed in animals. Bistramide A (1.4 x 10(-6) M) did not alter the resting potential of frog heart and skeletal muscle but reduced the amplitude and duration of cardiac action potential and prolonged the interval between action potentials. Bistramide A also has a marked cytotoxic effect on cancer cells KB (IC50 = 4.5 x 10(-8) M) and P 388 (IC50 = 2.0 x 10(-8) M) and on normal endothelial cells (IC50 = 2.2 x 10(-8) M). However, it has not been possible to relate the cytotoxic property to the symptoms of intoxication. Bistramide A may originate from the urochordate itself or from symbiotic algae.

Synthesis and in vitro cytotoxicity of lipidic alcohols and amines.

General methods for the conversion of unsaturated fatty acids into alcohols and amines and the preparation of lipidic 1,2-diamines were developed. The in vitro cytotoxicity of the synthetic lipidic compounds was tested against two different cell lines (P388 and NSCLCN6). Oleyl amine was the most active among the lipidic alcohols and monoamines. However, the saturated lipidic 1,2-hexadecanediamine exhibited the highest cytotoxicity (IC50 0.1 microgram/ml and 1.1 micrograms/ml).

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.

Comparative study of the antitumor activity of bistramides A, D and K against a non-small cell broncho-pulmonary carcinoma.

Bistramides A, D and K are substances extracted from the marine ascidian Lissoclinum bistratum Sluiter that are capable of inducing in vitro terminal differentiation (G1DT) of cells from a non-small cell broncho-pulmonary carcinoma (NSCLCN6), but present different in vitro toxicities. This study shows that only the least toxic bistramides D and K possess an antitumor activity. These two substances could be administered as a continuous treatment which would induce terminal differentiation of stem cells at their entry into the cell cycle, thereby causing their destruction.

Synthesis and cytotoxicity of aminosterols: activity studies on a non-small-cell bronchopulmonary carcinoma line (NSCLC-N6).

Various new aminosterols were synthesized. The antiproliferative activity of these compounds (I-IV) was studied in vitro on a continuous human non small-cell bronchopulmonary carcinoma line (NSCLC-N6) at the cell cycle level. The histograms indicate cell blockage in Phase Gl (compound I-III) associated with a reduction in the number of cells phases S and G2M and appearance of cellular debris derived from cells in Phase G1.

Subtractive hybridization and differential screening identified two genes differentially expressed after induction of in vitro (atypical) terminal differentiation in the NSCLC-N6 cell line by a marine substance (bistramide K).

Non-small-cell lung carcinoma is generally refractory to chemotherapy. The difficulties that arise in the treatment of this type of tumor make it necessary to develop new therapeutic strategies. Previous work done in our laboratory showed that a marine substance named bistramide K induced in vitro (atypical) terminal differentiation of NSCLC-N6 cell line. This activity is linked to a growth arrest of NSCLC-N6 cell line and an irreversible block at the G1 phase of the cell cycle (G1DT). In order to identify the genes that could be expressed after the treatment by the drug, we constructed a subtractive cDNA library with enriched mRNA extracted from BK-treated NSCLC-N6. After differential hybridization and DNA sequencing, we identified two sequences. The sequence identified for the clone 8 showed strong homology to the sequence of the ribosomal protein L35A. The sequence identified for the clone 4 did not show any homology with known sequences in official gene data banks.

Antiproliferative effects of an organic extract from the marine diatom Skeletonema costatum (Grev.) Cleve. Against a non-small-cell bronchopulmonary carcinoma line (NSCLC-N6).

An organic extract of the marine diatom Skeletonema costatum was studied in vitro for its effect on asynchronous cells of a human non-small-cell bronchoplumanory carcinoma line (NSCLC-N6). Cell growth appeared to be inhibited in the G1 phase of the cell cycle, and kinetic studies in pretreated cells showed that this growth arrest was irreversible. These events are related to a terminal maturation induction.

Effects of triterpenes from the stem bark of Dysoxylum cauliflorum on a non-small-cell bronchopulmonary carcinoma cell line (NSCLC-N6).

Six triterpenoids and one sesquiterpene were isolated from the ethanolic extract of the stem bark of Dysoxylum cauliflorum. Their structures were determined from 1D and 2D NMR and mass spectral data. Only compound 1 was cytostatic. Kinetic studies with ethyl eichlerianoate 1 demonstrated that this growth arrest was irreversible and cytofluorimetric analysis with compound 1 showed a complete block of NSCLC-N6 cells in the G1 phase. These events were related to a terminal maturation induction.

Antiproliferative effects of a product isolated from the gorgonian Rumphella aggregata.

A fraction isolated from the gorgonian Rumphella aggregata (Plexauridae) was studied vitro on asynchronous cells of a human non-small-cell-bronchopulmonary-carcinoma line (NSCLC-N6). Cell growth appeared to be inhibited in the Gl phase of the cell cycle, and kinetic studies in pretreated cells showed that this growth arrest was irreversible. These events seem to show a terminal maturation induced by this new product.

Effect of four genes (ALDH1, NRF1, JAM and KBL) on proliferation arrest in a non-small cell bronchopulmonary cancer line.

Despite new protocols, non-small cell bronchopulmonary cancers are still difficult to treat by current chemotherapeutic procedures. Thus, it is essential to define new treatment strategies and detect new therapeutic targets. In order to define these new targets, this study applied the "differential display" (DD) technique to the NSCLC-N6 cell line treated with VT1 [methyl-4-methoxy-3-(3-methyl-2-butanoyl)benzoate]. VT1 induces arrest of the NSCLC-N6 cell cycle in the G1-phase, followed by cell death. DD enabled us to detect seven overexpressed mRNAs during treatment, four of which corresponded to identified genes: aldehyde dehydrogenase 1, nuclear transcription factor Nrfl, junctional adhesion molecule, and amino-ketobutyrate ligase. An antisense strategy showed that amino-ketobutyrate ligase is involved in the proliferation arrest of NSCLC-N6 cells in the G1-phase after VT1 treatment.

Study of in vitro drug sensitivity on a newly established cell line from a primary bronchial epidermoid carcinoma of human origin (NSCLCN6).

We studied a cell line established from a primary non-small-cell lung cancer (non-SCLC) of human origin and characterized by midly differentiated epidermoid carcinoma, a human karyotype and keratin expression. Doubling time was about 48 h in vitro and 12 days when transplanted into nude mice. In vitro, this cell line was mainly sensitive to dactinomycin and mitotic poisons such as Vinca alkaloids. Most chemotherapeutic drugs proved ineffective. Our findings are comparable to previous results in patients who showed 30% objective response and less than 5% complete response regardless of the therapeutic associations used against non-SCLC. Our line would also seem to provide a good model for studying new potentially antitumor substances.

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.

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.

Terminal differentiation in a non-small-cell bronchopulmonary carcinoma correlates with increased expression of p53.

We studied the pharmacomodulating effects of a marine substance, bistramide D, which is capable of inducing terminal differentiation on the expression of the c-erb-B1, ras, src, myc and p53 genes in the NSCLC-N6 cell line established from a non-small cell lung carcinoma. Analysis (subsequent to treatment) demonstrated that among the genes for which it was possible to detect expression, namely c-erb-B1, c-myc and p53, only the expression of the p53 gene varied significantly. The increase of the expression rate of the p53 gene underlines its prominent role in the control of cell proliferation and differentiation.

Antitumor and antiproliferative effects of a fucan extracted from ascophyllum nodosum against a non-small-cell bronchopulmonary carcinoma line.

Fucans, sulfated polysaccharides extracted from brown seaweeds, have been shown to be endowed with inhibitory effects cell growth in various experimental models. We studied both the antiproliferative and antitumor properties of a fucoidan extract (HF) obtained from the brown seaweed Ascophyllum nodosum on a cell line derived from a non-small-cell human bronchopulmonary carcinoma (NSCLC-N6), this type of carcinoma is particularly chemo-resistant. HF exerts in vitro a reversible antiproliferative activity with a block observed in the G1 phase the cell cycle. Studies performed with the NSCLC-bearing nude mice show antitumor activity at subtoxic doses. These preliminary results indicate that HF exhibits inhibitory effect both in vitro and in vivo and is very potent antitumor agent in cancer therapy.

Cytotoxicity against human leukemic cell lines, and the activity on the expression of resistance genes of flavonoids from Platanus orientalis.

The cytotoxic activity of three flavonoids, belonging to the kaempherol series, was evaluated against 15 human leukemic cell lines. Flavonoids bearing acyl substituants, 2 and 3, were found to be the most active compounds. A further compound, 1, was examined for its ability to modulate the expression of MDR-1 and GST-pi resistance genes and compounds 2 and 3 for their effect on the uptake of [3H]-thymidine as a marker of DNA synthesis.