Establishment and expression of multidrug resistance-related genes of human colon carcinoma LoVo/Adr cell line / 中华消化杂志

ABSTRACT

Objective To establish human colon carcinoma LoVo/Adr cell line with multidrug resistance (MDR) and to study its MDR mechanism. Methods MDR cell line (LoVo/Adr) was induced by stepwise selection on exposure to increasing doses of adriamycin (ADR). The MDR of LoVo/Adr was detected by MTT assay and the distribution of its cell cycle was detected by flow cytometry. The expression of MDR related genes, including mdr1, MRP, GST ? and TopoⅡ was measured by RT PCR and the level of P gp was detected by immunohistochemistry. Results Compared with parental cells, the resistance line had a slower growth rate and longer doubling time. It was larger and mixed with giant cells in different sizes and the number of cells in S phase decreased while that in G1, G2 phase increased. The LoVo/Adr cell line showed 61 fold, 14 fold, 3 fold, 9 fold and 1 fold higher resistance to ADR, VCR, MMC, CTX and 5 FU respectively than its parental cell line. It was also cross resistant to VCR, MMC and CTX, but not to 5 FU. The parental LoVo cells showed no mdr1 expression and the level of mdr1 mRNA expression increased gradually according to the concentration of ADR in resistant cell lines, and the level of GST ? mRNA was only increased significantly in the induced initial stage, although the parental LoVo cells expressed a low level of GST ?. MRP mRNA expression was not detected in both parental cell line and resistant cell lines. The level of Topo ⅡmRNA remained stable. Conclusions LoVo/Adr cell line offers a model with a typical MDR phenotype for the study of MDR in human colon cancer. Its drug resistance was mediated by mdr1 and GST ?, not MRP and TopoⅡ.