Tannin-albumin particles as stable carriers of medicines

Background: The effectiveness of a drug is dependent on its accumulation at the site of therapeutic action, as well as its time in circulation. The aim of the research was the creation of stable albumin/tannin (punicalagin, punicalin) particles, which might serve for the delivery of medicines. Methods: Numerous chromatographic and analytical methods, docking analyses and in vivo testing were applied and used. Results: Stable tannin-albumin/medicine particles with a diameter of ∼100 nm were obtained. The results of in vivo experiments proved that tannin-albumin particles are more stable than albumin particles. Conclusion: Based on the experiments and docking analyses, these stable particles can carry an extended number of medicines, with diverse chemical structures.

Understanding Rifampicin Resistance in Tuberculosis through a Computational Approach

The disease tuberculosis, caused by Mycobacterium tuberculosis (MTB), remains a major cause of morbidity and mortality in developing countries. The evolution of drug-resistant tuberculosis causes a foremost threat to global health. Most drug-resistant MTB clinical strains are showing resistance to isoniazid and rifampicin (RIF), the frontline anti-tuberculosis drugs. Mutation in rpoB, the beta subunit of DNA-directed RNA polymerase of MTB, is reported to be a major cause of RIF resistance. Amongst mutations in the well-defined 81-base-pair central region of the rpoB gene, mutation at codon 450 (S450L) and 445 (H445Y) is mainly associated with RIF resistance. In this study, we modeled two resistant mutants of rpoB (S450L and H445Y) using Modeller9v10 and performed a docking analysis with RIF using AutoDock4.2 and compared the docking results of these mutants with the wild-type rpoB. The docking results revealed that RIF more effectively inhibited the wild-type rpoB with low binding energy than rpoB mutants. The rpoB mutants interacted with RIF with positive binding energy, revealing the incapableness of RIF inhibition and thus showing resistance. Subsequently, this was verified by molecular dynamics simulations. This in silico evidence may help us understand RIF resistance in rpoB mutant strains.

Association of RHAMM with E2F1 promotes tumour cell extravasation by transcriptional up-regulation of fibronectin

Dissemination of cancer cells from primary to distant sites is a complex process; little is known about the genesis of metastatic changes during disease development. Here we show that the metastatic potential of E2F1-dependent circulating tumour cells (CTCs) relies on a novel function of the hyaluronan-mediated motility receptor RHAMM. E2F1 directly up-regulates RHAMM, which in turn acts as a co-activator of E2F1 to stimulate expression of the extracellular matrix protein fibronectin. Enhanced fibronectin secretion links E2F1/RHAMM transcriptional activity to integrin-β1-FAK signalling associated with cytoskeletal remodelling and enhanced tumour cell motility. RHAMM depletion abolishes fibronectin expression and cell transmigration across the endothelial layer in E2F1-activated cells. In a xenograft model, knock-down of E2F1 or RHAMM in metastatic cells protects the liver parenchyma of mice against extravasation of CTCs, whereas the number of transmigrated cells increases in response to E2F1 induction. Expression data from clinical tissue samples reveals high E2F1 and RHAMM levels that closely correlate with malignant progression. These findings suggest a requirement for RHAMM in late-stage metastasis by a mechanism involving cooperative stimulation of fibronectin, with a resultant tumourigenic microenvironment important for enhanced extravasation and distant organ colonization. Therefore, stimulation of the E2F1-RHAMM axis in aggressive cancer cells is of high clinical significance. Targeting RHAMM may represent a promising approach to avoid E2F1-mediated metastatic dissemination.