Figure 5.

Paclitaxel does not stabilize the microtubules in the II18 cell line for 48 h, whereas it does in the other cell lines, with a peak between 6 or 12 h. (A), Immunoblots of proteins from lung cancer cell lines with antibodies against α-tubulin. The loading quantity was equal to 10 μg proteins from three 3.3 μg total proteins from the cell lines exposed to 3.2 nM paclitaxel. Cells were lysed in hypotonic buffer for 5 min at 37°C followed by separation of the soluble (S) and polymerized (P) fractions by centrifugation. (B), The percentage of polymerized tubulin was obtained by dividing the densitometric value of the polymerized tubulin (insoluble) by the total tubulin contents.