QSAR of microtubule stabilizing dictyostatins

CHED 1314

Kia L. Montgomery, Kia.Montgomery@gmail.com, Department of Chemistry, Grambling State University, 403 Main St., GSU Box 4218, Grambling, LA 71245 and Billy W. Day, Departments of Pharmaceutical Sciences and of Chemistry, University of Pittsburgh, 10017 BST3, 3501 Fifth Avenue, Pittsburgh, PA 15213.
Microtubule stabilization is a validated mechanism for cancer chemotherapy. Dictyostatin, an analog of the failed drug discodermolide, binds to the â-tubulin subunit of microtubules, inhibiting cell growth by blockage at the G2/M phase of the cell cycle. Dictyostatin and analogs were synthesized and their antiproliferative activities against ovarian cancer cells were measured. These data, along with that from some discodermolides, were used to determine a quantitative structure-activity relationship (QSAR). Molecular models of the dictyostatins were built from NMR coordinates of discodermolide and their global minimum energy conformations determined. Models were superimposed to provide maximum structural overlap and a collection of electronic, thermodynamic and steric descriptors were calculated for each model. A special multiple linear regression analysis, the genetic function approximation, was used to find the descriptors that best explained the differences in activity. A population of statistically compelling QSAR equations was found and may be useful in future analog design.