BACKGROUND

Some mutations of androgen receptor (AR) confer resistance to antiandrogen to prostate cancer (PC) cells. Previously we reported that LNCaP-cxD2 cells established from androgen-dependent LNCaP-FGC PC cells as an antiandrogen bicalutamide-resistant subline harbor W741C/L mutation in the AR gene. In this report, we examined one possible mechanism of the resistance.

METHODS

Change in the gene expression and the protein levels relevant to mutagenesis in LNCaP-FGC cells during bicalutamide-treatment was assessed. The AR sequence of bicalutamide-resistant LNCaP-cxD2 cells was compared with that of parental LNCaP-FGC cells.

RESULTS

The expression of DNA polymerases (Pol) switched from high-fidelity subset to error-prone subset, and DNA mismatch repair proteins (MMR) were down-regulated. The rate of multiple mutations in the AR gene was higher in LNCaP-cxD2 cells than LNCaP-FGC cells.

CONCLUSIONS

These results suggest the hypermutational state might occur in LNCaP-FGC cells during bicalutamide-treatment, which might create the W741C/L mutant AR leading to bicalutamide-resistance.