Bioprocessing of Epothilone B from Aspergillus fumigatus under solid state fermentation: Antiproliferative activity, tubulin polymerization and cell cycle analysis.

Epothilone derivatives have been recognized as one of the most powerful anticancer drugs towards solid tumors, for their unique affinity to bind with ß-tubulin microtubule arrays, stabilizing their disassembly, causing cell death. Sornagium cellulosum is the main source for Epothilone, however, the fermentation bioprocessing of this myxobacteria is the main challenge for commercial production of Epothilone. The metabolic biosynthetic potency of epothilone by Aspergillus fumigatus, an endophyte of Catharanthus roseus, raises the hope for commercial epothilone production, for their fast growth rate and feasibility of manipulating their secondary metabolites. Thus, nutritional optimization of A. fumigatus for maximizing their epothilone productivity under solid state fermentation process is the objective. The highest yield of epothilone was obtained by growing A. fumigatus on orange peels under solid state fermentation (2.2 µg/g), bioprocessed by the Plackett-Burman design. The chemical structure of the extracted epothilone was resolved from the HPLC and LC-MS/MS analysis, with molecular mass 507.2 m/z and identical molecular fragmentation pattern of epothilone B of S. cellulosum. The purified A. fumigatus epothilone had a significant activity towards HepG2 (IC50 0.98 µg/ml), Pancl (IC50 1.5 µg/ml), MCF7 (IC50 3.7 µg/ml) and WI38 (IC50 4.6 µg/ml), as well as a strong anti-tubulin polymerization activity (IC50 0.52 µg/ml) compared to Paclitaxel (2.0 µg/ml). The effect of A. fumigatus epothilone on the immigration ability of HepG2 cells was assessed, as revealed from the wound closure of the monolayer cells that was estimated by ~ 63.7 and 72.5%, in response to the sample and doxorubicin, respectively, compared to negative control. From the Annexin V-PI flow cytometry results, a significant shift of the normal cells to the apoptosis was observed in response to A. fumigatus epothilone by ~ 20 folds compared to control cells, with the highest growth arrest of the HepG2 cells at the G0-G1 stage.

Discovery of (2-(pyrrolidin-1-yl)thieno[3,2-d]pyrimidin-4-yl)(3,4,5-trimethoxyphenyl)methanone as a novel potent tubulin depolymerizing and vascular disrupting agent.

In this study, a series of 2-substituted thieno[3,2-d]pyrimidin-4-yl(3,4,5-trimethoxyphenyl)methanones were designed, synthesized and evaluated as novel anti-tubulin polymerization and vascular disrupting agents. A pyrrolidin-1-yl derivative, compound 20, exhibited strong antiproliferative activities (average IC50 = 13.4 nM) against four cancer cell lines. 20 also showed retained potency toward paclitaxel-resistant A549 cells. 20 could significantly inhibit tubulin polymerization with an IC50 of 1.6 µM. 20 displayed strong induction of G2/M arrest and apoptosis through the mitochondrial pathway. Dose-dependent suppression of the migration of cancer cells and the formation of a vascular network were observed after treatment with 20. The acceptable microsomal stability implied that it is worth conducting further study on the analogues of 20 as novel drug candidates of CBSIs.

Design and synthesis of (2-(phenylamino)thieno[3,2-d]pyrimidin-4-yl)(3,4,5-trimethoxyphenyl)methanone analogues as potent anti-tubulin polymerization agents.

Anti-tubulin polymerization agents can disrupt tumor-vascular to exhibit anti-cancer potency. In this study, a series of substituted (2-(phenylamino)thieno[3,2-d]pyrimidin-4-yl)(3,4,5-trimethoxyphenyl)methanone analogues were designed and synthesized as anti-tubulin polymerization agents that interact with colchicine binding site. The anti-proliferative assay indicated that most of the target compounds displayed moderate to high potencies towards five tumor cell lines. The structure-activity relationship of these analogues was summarized. The most potent compound 14 was selected to assay its inhibition on the tubulin polymerization. 14 displayed potent inhibition against tubulin polymerization with an IC50 value of 4.1 ±â€¯0.1 µM. The colchicine competition assay demonstrated that 14 inhibited tubulin polymerization by binding to the colchicine-binding site of tubulin. The molecular modeling study elucidated the binding mode of 14 in the colchicine binding site. The result of confocal immunofluorescent study proved that 14 can quickly disrupt the microtubules of Hela cells in a concentration dependent manner. Some experiments at cellular level were conducted to investigate the effects of 14 on cellular morphology, cell colony formation, cell cycle distribution, cell apoptosis and mitochondrial changes. The results demonstrated that 14 is a potent anti-tubulin agent with strong concentration dependent effect of inhibition of colony formation, induction of G2/M arrest and induction of apoptosis through mitochondrial pathway.

Optimization of substituted cinnamic acyl sulfonamide derivatives as tubulin polymerization inhibitors with anticancer activity.

A new series of novel cinnamic acyl sulfonamide derivatives were designed and synthesized and evaluated their anti-tubulin polymerization activities and anticancer activities. One of these compounds, compound 5a with a benzdioxan group, was observed to be an excellent tubulin inhibitor (IC50 = 0.88 µM) and display the best antiproliferative activity against MCF-7 with an IC50 value of 0.17 µg/mL. Docking simulation was performed to insert compound 5a into the crystal structure of tubulin at colchicine binding site to determine the probable binding model. 3D-QSAR model was also built to provide more pharmacophore understanding that could be used to design new agents with more potent anti-tubulin polymerization activity.