Establishment of Paclitaxel-Resistant Cell Line and the Underlying Mechanism on Drug Resistance

Objective

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

Methods

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.

Results

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.

Conclusions

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.