Toxic potential of botulinum toxin type A on senescence in a Drosophila melanogaster model.

Botulinum toxin type-A (BoNT/A) application, especially neurological disorders, has been spread nowadays while it may cause side effects. The current study aimed to assess the BoNT/A dose-dependent effect on induction of aging in the Drosophila melanogaster model. The third instar larvae of Drosophila melanogaster were exposed to » LC50, ½ LC50, and LC50 of BoNT/A in the Drosophila diet for 48 h while H2O2 1% was used as a positive control. After the exposure time, some larvae were collected for molecular study, including gene expression analysis, comet assay, oxidative stress markers, and the phenotype changes. BoNT/A induced dose-dependent cytotoxicity, elevated reactive oxygen species (ROS) levels, and superoxide dismutase (SOD) enzyme activity. In addition, it caused DNA damage and activated caspase-3 and -9, and reduced the body size of the fly, especially in high doses. In line with the purpose of the study, aging markers, including ß-galactosidase (ß-gal), p16, p21, p38, and p53, were up-regulated by BoNT/A low dose. BoNT/A activates the aging pathway in the low dose, and increasing the dose induces toxicity, including oxidative stress, DNA damage, and apoptosis.

Anticancer properties of Teucrium persicum in PC-3 prostate cancer cells.

Crude extracts or phytochemicals obtained from some plants have potential anti-cancer properties. Teucrium persicum is an Iranian endemic plant belonging to the Lamiaceae family which has traditionally been used to relieve abdominal pains. However, the anti-cancer properties of this species of the Teucrium genus have not been investigated previously. In this study, we have used a highly invasive prostate cancer cell line, PC-3, which is an appropriate cell system to study anti-tumor properties of plants. A methanolic extract obtained from T persicum potently inhibited viability of PC-3 cells. The viability of SW480 colon and T47D breast cancer cells was also significantly decreased in the presence of the T persicum extract. Flow cytometry suggested that the reduction of cell viability was due to induction of apoptosis. In addition, the results of wound healing and gelatin zymography experiments supported anti-cell invasion activity of T persicum. Interestingly, sublethal concentrations of T persicum extract induced an epithelial-like morphology in a subpopulation of cells with an increase in E-Cadherin and ß-Catenin protein levels at the cell membrane. These results strongly suggest that T persicum is a plant with very potent anti-tumor activity.

Regulation of GSK-3beta and beta-Catenin by Galphaq in HEK293T cells.

Recent studies have shown that heterotrimeric G proteins are involved in the regulation of the canonical Wnt/beta-Catenin pathway. However, the mechanism(s) behind this involvement is (are) poorly understood. Our previous results have shown that activation of Galphaq in Xenopus oocytes leads to inhibition of GSK-3beta and stabilization of the beta-Catenin protein, suggesting that Galphaq might stabilize beta-Catenin via inhibition of GSK-3beta. In this study, we have observed similar results in HEK293T cells. In these cells optimal activation of endogenous Galphaq by expressing M3-muscarinic acetylcholine receptor (with or without carbachol treatment), or exposing the cells to thrombin led to an increase of 2 to 3-fold in endogenous cytoplasmic beta-Catenin protein levels. In addition, expression of the activated mutant of Galphaq (GalphaqQL) dramatically enhanced accumulation of exogenous beta-Catenin with no effect on beta-catenin (CTNNB1) gene transcription. The Galphaq-mediated cellular accumulation of beta-Catenin was blocked by expression of a minigene encoding a Galphaq specific inhibitory peptide but not by a minigene encoding a Galphas blocking peptide. Also, expression of GalphaqQL led to a significant reduction in GSK-3beta kinase activity, supporting the idea that the positive role of Galphaq signaling in inducing cellular accumulation of beta-Catenin is mediated through inhibition of GSK-3beta.