NCI-H460 (lung), HCT116 (colon), MCF7 (breast), PC3 (prostate), and HeLa (cervical) cells with IC50 values from 0.1 to 0.3 muM. A structure-activityrelationship (SAR) study at the 2- and 4-position of the quinazoline core lead to the discovery of more potent anticanceragents (14, 16, 17, 19, 24, and 31). The results of an in vitro tubulin polymerization assay and fluorescent-based colchicine site competition