Arylthio Indoles Research Articles

Application of GA-MLR for QSAR Modeling of the Arylthioindole Class of Tubulin Polymerization Inhibitors as Anticancer Agents.

Microtubules are dynamic filamentous cytoskeletal proteins which have used widely in cancer chemotherapy. Generally, the action of these compounds depends on binding to the tubulin proteins which are α, β -heterodimers that form the core of the microtubules. Arylthioindoles (ATIs) inhibit tubulin polymerization by binding to the colchicine site, inhibiting the binding of colchicine to tubulin. QSAR modeling play an important role in modern medicinal chemistry, presenting a unique potential for transforming the early phases of drug research, in terms of time and money savings. In this study we are intending to achieve some useful information about the structural properties of mentioned ATIs using the QSAR modeling method. In this research, the QSAR modeling has been employed to evaluate the efficacy of ATIs derivatives in the inhibition of tubulin polymerization. The best multivariate linear model for each training and test data subset calculated using both genetic algorithm-multiple linear regressions (GA-MLR) and stepwise-multiple linear regressions (S-MLR) methods. The best RS trial set has been selected by comparing the two different QSAR modeling results in all train and test subsets. Finally, the S-MLR and GA-MLR results were compared for finding the best random selection (RS) subset. The molecular structures and experimental activity values for inhibition of tubulin polymerization obtained from the literature. Here, using Dragon package over 1185 molecular descriptors such as RDF, GETAWAY, WHIM, 3D-MoRSE descriptors, and functional group descriptors derived for proper characterizing the arylthioindole derivatives structures. These molecular descriptors reduced to 437 one by eliminating the constant variables, collinear descriptors and the variables having low correlation with response. In fact in order to obtain the best RS subsets in the mentioned method, the random samplings of the training subset (80% of data) were carried out 20 times and the remaining molecules (20% of data) considered as external validation set. The QSAR models were constructed using stepwise-MLR and GA-MLR. In order to select important variables the GA-MLR and S-MLR methods applied on the training subsets after data splitting. The best MLR models (models with high fitness function values) with four, five and six variables built to obtain the best QSAR model. The best MLR model had four parameters in both GA-MLR and S-MLR methods. The best significant relationships, using comparison of Q2 of models, for the IC50 values of tubulin assembly in the models obtained in S-MLR and GA-MLR methods are presented for all of the random sets and SOM set. The result of external validation indicates that in the study of inhibition of tubulin polymerization, the Q2test values are 0.7242 and 0.3215 for GA-MLR and S-MLR methods respectively. Considering the results which obtained in both methods it can be concluded that in variable selecting the GA-MLR method is more powerful than the S-MLR method.

Mitotic cell death induction by targeting the mitotic spindle with tubulin-inhibitory indole derivative molecules.

Tubulin-targeting molecules are widely used cancer therapeutic agents. They inhibit microtubule-based structures, including the mitotic spindle, ultimately preventing cell division. The final fates of microtubule-inhibited cells are however often heterogeneous and difficult to predict. While recent work has provided insight into the cell response to inhibitors of microtubule dynamics (taxanes), the cell response to tubulin polymerization inhibitors remains less well characterized. Arylthioindoles (ATIs) are recently developed tubulin inhibitors. We previously identified ATI members that effectively inhibit tubulin polymerization in vitro and cancer cell growth in bulk cell viability assays. Here we characterise in depth the response of cancer cell lines to five selected ATIs. We find that all ATIs arrest mitotic progression, yet subsequently yield distinct cell fate profiles in time-lapse recording assays, indicating that molecules endowed with similar tubulin polymerization inhibitory activity in vitro can in fact display differential efficacy in living cells. Individual ATIs induce cytological phenotypes of increasing severity in terms of damage to the mitotic apparatus. That differentially triggers MCL-1 down-regulation and caspase-3 activation, and underlies the terminal fate of treated cells. Collectively, these results contribute to define the cell response to tubulin inhibitors and pinpoint potentially valuable molecules that can increase the molecular diversity of tubulin-targeting agents.

Design and synthesis of 2-heterocyclyl-3-arylthio-1H-indoles as potent tubulin polymerization and cell growth inhibitors with improved metabolic stability.

New arylthioindoles (ATIs) were obtained by replacing the 2-alkoxycarbonyl group with a bioisosteric 5-membered heterocycle nucleus. The new ATIs 5, 8, and 10 inhibited tubulin polymerization, reduced cell growth of a panel of human transformed cell lines, and showed higher metabolic stability than the reference ester 3. These compounds induced mitotic arrest and apoptosis at a similar level as combretastatin A-4 and vinblastine and triggered caspase-3 expression in a significant fraction of cells in both p53-proficient and p53-defective cell lines. Importantly, ATIs 5, 8, and 10 were more effective than vinorelbine, vinblastine, and paclitaxel as growth inhibitors of the P-glycoprotein-overexpressing cell line NCI/ADR-RES. Compound 5 was shown to have medium metabolic stability in both human and mouse liver microsomes, in contrast to the rapidly degraded reference ester 3, and a pharmacokinetic profile in the mouse characterized by a low systemic clearance and excellent oral bioavailability.

Molecular modelling studies on Arylthioindoles as potent inhibitors of tubulin polymerization

The crucial role played by microtubules in the life of eukaryotic cell makes tubulin an important route for the anticancer therapy. The Arylthioindoles (ATIs) along with the corresponding ketone and methylene compounds are potent tubulin assembly inhibitors. We are here reporting the result of a series of docking and molecular dynamics experiments on this series of compounds. The results obtained from our in silico studies not only provided us with an insight on the nature of the binding of the ATIs to tubulin, but were also at the core of the design of a new series of potent inhibitors of tubulin polymerization.

New Arylthioindoles: Potent Inhibitors of Tubulin Polymerization. 2. Structure−Activity Relationships and Molecular Modeling Studies

Arylthioindoles (ATIs) that possess a 3-methoxyphenylthio or a 3,5-dimethoxyphenylthio moiety at position 2 of the indole ring were effective tubulin assembly inhibitors, but weak inhibitors of MCF-7 cell growth. ATIs bearing a 3-(3,4,5-trimethoxyphenyl)thio moiety were potent tubulin polymerization inhibitors, with IC(50)s in the 2.0 (35) to 4.5 (37) microM range. They also inhibited MCF-7 cell growth at nanomolar concentrations. The 3,4,5-trimethoxy substituted ATIs showed potencies comparable to those of the reference compounds colchicine and combretastatin A-4 in both tubulin assembly and cell growth inhibition assays. Dynamics simulation studies correlate well with the observed experimental data. Furthermore, from careful analysis of the biological and in silico data, we can now hypothesize a basic pharmacophore for this class of compounds.