Purpose: To determine the prevalence and the prognostic value of microtubule component expression in tumors of patients with locally advanced or metastatic non^small cell lung cancer (NSCLC). Experimental Design: Expression of microtubular components was immunohistochemically examined in 93 tumor samples from untreated patients with stage III and IV NSCLC. All patients received vinorelbine-based chemotherapy. Response to chemotherapy, progressionfree survival, and overall survival were correlated with the expression of microtubule proteins. Results: The response rate was 27.3% (21 partial responses among 77 valuable patients). Although expression of microtubule components was not associated with the response rate, high class III h-tubulin expression was correlated with resistance to vinorelbine, defined as disease progression under treatment. Patients whose tumors expressed high levels of class III h-tubulin isotype had shorter progression-free survival and overall survival (P = 0.002 and 0.001, respectively). High D2 a-tubulin expression was associated with a shorter overall survival (P = 0.018). Tubulin II levels were not found to be correlated with patient outcome. A multivariate analysis, taking into account sex, age, histology, stage, weight loss, and class II h-tubulin, class III h-tubulin, and D2 a-tubulin levels, confirmed that class III h-tubulin expression was independently correlated with progression-free survival (P = 0.04) and overall survival (P = 0.012). Conclusions:These findings suggest that a high level of expression of class III h-tubulin in tumor cells is associated with resistance to vinorelbine and a poor prognosis in patients with NSCLC receiving vinorelbine-based chemotherapy.

In the present study, we compared the dynamics and composition of microtubules in cell lines derived from the human breast adenocarcinoma MCF-7 containing either the wild-type p53 (wt-p53; MN1) or a dominant-negative variant of p53 gene (mut-p53; MDD2). Mut-p53 cells were significantly resistant to the cytotoxicity of the microtubule-targeted drugs (vinca alkaloids and taxanes), as compared with wt-p53 cells. Studies by high-resolution time-lapse fluorescence microscopy in living cells indicated that the dynamics of microtubules of mut-p53 cells were altered in complex ways and were significantly increased as compared with microtubules in wt-p53 cells. The percentage of time microtubules spent in growing and shortening phases increased significantly, their catastrophe frequency increased, and their overall dynamicity increased by 33%. In contrast, their shortening rate and the mean length shortened decreased. Cells containing mut-p53 displayed increased polymerisation of tubulin, increased protein levels of the class IV b-tubulin isotype, STOP and survivin, and reduced protein levels of class II b-tubulin isotype, MAP4 and FHIT. We conclude that p53 protein may contribute to the regulation of microtubule composition and function, and that alterations in p53 function may generate complex microtubule-associated mechanisms of resistance to tubulin-binding agents.

We report the synthesis of 5-hydroxy-7-methoxy-2-phenyl-4-quinolones and their biological activity as antitumor agents. These molecules were initially evaluated for their ability to induce cell cycle arrest in the G2/M phase. Compounds that showed significant G2/M cell cycle arrest were tested for antiproliferative activity using both the MTT assay and the NCI in vitro 60 cell line human tumor screen. The 5-hydroxy-7-methoxy-2-phenyl-4-quinolone (3a) and 2-(3-fluorophenyl)-5-hydroxy-7-methoxy-4-quinolone (3f) were the most active in the cell cycle arrest test whereas 3f was found to be the most active in the MTT assay. In terms of structural requirements, we found that the presence of a 5-hydroxyl group, a 7-methoxy group, and an unsubstituted N1 were essential for the antimitotic activity. In accordance with the literature, a fluoro group at the 3'- or 2'-position and a methoxy or a chloro group at the 3'-position were found to be highly advantageous for both the cell cycle arrest and the antiproliferative activities.