MMPT: a thiazolidin compound inhibits the growth of lung cancer H1792 cells via Fas-mediated and caspase-dependent apoptosis pathway.

MMPT, a thiazolidin compound, was identified in our laboratory as a novel antineoplastic agent with a broad spectrum of antitumor activity against many human cancer cells. However, the related mechanism has yet not been revealed. In this study, we investigated the cellular and molecular events underlying the antitumor function of this compound in human lung adenocarcinoma H1792 cells, focusing on the early cytotoxic effect. Treatment of H1792 cancer cells with MMPT (0.1-100 microM for 24-72 h) resulted in a growth inhibition in a dose and time-dependent manner, determined by MTT assay. This effect was accompanied by apoptosis, evidenced by Nucleosome ELISA, H33258 stained assay, and Sub-G1 analysis. Our data showed that MMPT caused activation of caspase-3, caspase-6 and caspase-8, but not caspase-9. The finding that MMPT induced apoptosis through a membrane-mediated mechanism was supported by the up-regulated expression of Fas (CD95/APO-1), and Fas ligand. Overall, our results demonstrated that MMPT induced growth inhibition of H1792 cells through a Fas-mediated and caspase-dependent apoptosis pathway, which suggested that MMPT might be used as a Fas/FasL and caspases promoter to initiate lung cancer cell apoptosis.

Tetrazolium violet induces apoptosis via caspases-8, -9 activation and Fas/FasL up-regulation in rat C6 glioma cells.

Tetrazolium violet (TV), a tetrazolium salt, was synthesized as a novel and potent anticancer agent with a broad spectrum of anticancer activity against many cancer cells. A previous study showed that tetrazolium violet inhibited cell growth, and induced cell cycle arrest and apoptosis in C6 Rat glioma cells. It also showed that treatment of cells with TV for 24 h resulted in a dramatic up-regulation of p53, and an increase in the activity of caspase-3, accompanied with a significant increase of Bax/Bcl-2 ratio. In this study, we further investigated which Fas/FasL and caspase were activated by TV during the apoptosis. Annexin-V-propidium iodide (PI) binding assay and nucleosome ELISA assay further indicated that TV induced a typical apoptosis, in a time-dose-dependent manner. The data showed that the activity of Fas/FasL and caspase-8 and -9 were significantly enhanced by the compound, which suggested that TV might be used as a Fas/FasL and caspases promoter to initiate brain cancer cell apoptosis.

Tetrazolium violet inhibits cell growth and induces cell death in C127 mouse breast tumor cells.

Tetrazolium violet (TV), a tetrazolium salt, has been applied in several fields, including estimating respiration rate, as a redox indicator of microbial growth, and for estimating the number of viable animal cells. It has recently been found that TV is capable of inducing apoptosis in rat glioblastoma cells by way of an elusive mechanism. In this study, we demonstrated that TV also induced apoptosis in mouse breast tumor C127 cells as evidenced by nucleus condensation and nucleus fragmentation. Our data showed that TV caused activation of caspase-3 and caspase-8, but not caspase-9. An enhancement in Fas and its two ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), might be responsible for the apoptotic effect induced by TV. Also, the results first reported that TV not only inhibited C127 cells proliferation but also blocked cell cycle progression in the G1 and G2 phase, determined by MTT assay and flow cytometry analysis. Immunofluorescence assay demonstrated that TV significantly increased the expression of p53 protein, which caused cell cycle arrest. Taken together, p53, Fas/FasL, and the caspase apoptotic system may participate in the antiproliferative activity of TV in C127 cells.

Tetrazolium violet induced apoptosis and cell cycle arrest in human lung cancer a549 cells.

Tetrazolium violet is a tetrazolium salt and has been proposed as an antitumor agent. In this study, we reported for the first time that tetrazolium violet not only inhibited human lung cancer A549 cell proliferation but also induced apoptosis and blocked cell cycle progression in the G1 phase. The results showed that tetrazolium violet significantly decreased the viability of A549 cells at 5-15 µM. Tetrazolium violet -induced apoptosis in A549 cells was confirmed by H33258 staining assay. In A549, tetrazolium violet blocked the progression of the cell cycle at G1 phase by inducing p53 expression and further up-regulating p21/WAF1 expression. In addition, an enhancement in Fas/APO-1 and its two forms of ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), as well as caspase, were responsible for the apoptotic effect induced by tetrazolium violet. The conclusion of this study is that tetrazolium violet induced p53 expression which caused cell cycle arrest and apoptosis. These findings suggest that tetrazolium violet has strong potential for development as an agent for treatment lung cancer.

[Cell brain abnormalities in carcinogenesis].

Cancer seriously threatens the health of humans. The mechanism underlying the carcinogenesis, however, is unclear. Among all the related hypotheses, the lately postulated 'cell brain' theory, challenging the conventional theory that gene abnormalities are the major players in carcinogenesis, is catching more and more attentions. According to this theory, the complex composes of the centrosome, centrioles, and connecting microtubules, and acts as the commandeering center of a cell in the structures and functions, equals to the brains of human being and animals, centering all the cellular activities. As far as carcinogenesis is concerned, cancer was interpreted by this theory as a brain illness' rather than a genetic disease. This article, based on the latest findings, reevaluated the roles of the composing parts of cell brain, discussed their correlations to cancer development, and further explored the mechanisms of carcinogenesis including hepatocarcinogenesis. It will contribute not only to improving cancer diagnosis and prevention but also to the design of novel anticancer agents, particularly the centrosome/cell brain-targeting agents.