Establishment of paclitaxel-resistant cell line and the underlying mechanism on drug resistance

The objective of this study was to establish a taxol (TAX)-resistant human ovarian carcinoma cell line and investigate its drug-resistant mechanism.

Using the dose calculated from clinical chemotherapy, we established a TAX-resistant human ovarian carcinoma cell line OC3/TAX300 by intermissive and repeated exposure to TAX of a high concentration at 300 μg/mL for 2 hours each time. The drug sensitivity was examined by tetrazolium dye (MTT) test. Distribution of cell cycle, DNA content analysis, and P-glycoprotein (P-gp) expression were detected by flow cytometry. We detected the differential gene expression by use of cDNA microarray. The reverse transcription-polymerase chain reaction and Western blot were used to verify the representative mRNA expression and their protein expression.

OC3/TAX300 cells were established after 10 months with stable resistance, and the drug resistance index was 6.70. It displayed significant cross-resistance to topotecan. Distribution of cell cycle revealed a higher percentage of G2 + M phase (P < 0.01), a lower percentage of S phase (P < 0.05), and overexpression of P-gp (P < 0.01). The cDNA microarray analysis showed that there were 134 significantly differential expression genes in all, of which up-regulated and down-regulated genes were 17 and 117, respectively. The up-regulated genes JAK2 (Janus kinase 2) and HSPC154 were confirmed by reverse transcription-polymerase chain reaction and Western blot.

The OC3/TAX300 cell line is an ideal model to investigate the mechanism of TAX resistance. Taxol resistance in this cell could be related to overexpression of P-gp and the change of cell cycle profiles. The differential expression genes of JAK2 and HSPC154 may be candidate genes associated with TAX resistance in ovarian carcinoma cell lines.