Modulation of drug resistance by α-tubulin in paclitaxel-resistant human lung cancer cell lines

• DOI: 10.1016/s0959-8049(00)00145-3
• Publication Date: 2002-07-25T17:15:05Z
• Authors: E. Kyu-Ho Han; L. Gehrke; S.K. Tahir; R.B. Credo; S.P. Cherian; H. Sham; S.H. Rosenberg; S.-C. Ng
• Keywords: DNA, Complementary; Lung Neoplasms; Paclitaxel; Blotting, Western; Cell Cycle; Blotting, Northern; Flow Cytometry; Transfection; Antineoplastic Agents, Phytogenic; DNA, Antisense; 3. Good health; 03 medical and health sciences; 0302 clinical medicine; Drug Resistance, Neoplasm; Tubulin; Tumor Cells, Cultured; Humans; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Division

Beta(beta)-tubulin isotype variation has recently been implicated in the modulation of resistance to paclitaxel in human lung cancer cells and in primary human ovarian tumour samples. Whether alpha-tubulin is involved in drug resistance has not been reported. We have generated a paclitaxel-resistant cell line (H460/T800) from the sensitive human lung carcinoma parental cell line NCI-H460. The resistant cells are more than 1000-fold resistant to taxol and overexpress P-glycoprotein. Interestingly, H460/T800 cells also overexpress alpha- and beta-tubulin as detected by Western blot analysis. From Northern blot analysis, the mechanism of tubulin overexpression appears to be post-transcriptional. To understand whether alpha-tubulin plays a role in drug resistance, we transfected antisense human kalpha1 cDNA construct into the H460/T800 paclitaxel-resistant cells. The antisense clones displayed a reduced alpha-tubulin expression, and the cells were 45-51% more sensitive to paclitaxel and other known antimitotic drugs, compared with vector transfected controls. Complementary experiments of transfecting the sense kalpha1 cDNA into H460 cells conferred a 1.8- to 3.3-fold increase in the IC(50) of several antimitotic agents. Our study suggests that alpha-tubulin is one of the factors that contributes to drug resistance.