Figure 8.

Effects of selected indolyl-pyridinyl-propenones on tubulin polymerization in cultured U251 cells. Cells were treated for 4 h with the indicated compounds at a final concentration of 3 μM and then fractionated under conditions designed to preserve the native polymerization state of the microtubules. The percentage of polymerized versus soluble tubulin was determined by immunoblot analysis as described in the Experimental Section. For each compound the fraction of tubulin in the polymerized state was expressed as a percentage of the polymerized tubulin determined in a parallel control culture treated with DMSO alone. The results represent the mean (±S.D.) of determinations from three separate experiments. The decreases in the percentage of polymerized tubulin in cells treated with 2j, 2l, 2m and colchicine (at 3 μM) were significant at p ≤ 0.05.