LNCAP/AR and a LnCAP/AR subline (LREX') with acquired resistance to 2nd generation antiandrogens

The treatment of advanced prostate cancer has been transformed by novel antiandrogen therapies such as enzalutamide. Using the LnCaP/AR xenograft model, we identified induction of glucocorticoid receptor (GR) expression as a common feature of drug resistant tumors. From a resistant xenograft tumor, we derived a GR expressing resistant subline called LREX' which maintains the resistant phenotype. mRNA expression was used to characterize resistant tissues. LnCaP/AR cells were injected into castrate mice and tumors were established. Mice were then treated with vehicle (Con), 4 days of anti-androgen (ARN-509 10mgkg), or were maintained on anti-androgen (10mg/kg ARN-509 or enzalutamide) until emergence of resistance. Resistant tissues continued to be exposed to anti-androgen through time of harvest. LREX' (LnCaP/AR Resistant to Enzalutamide Xenograft Derived) was derived from an enzalutamide resistant xenograft and was re-injected into castrate mice undergoing continual treatment with enzalutamide. The GR probe on the Illumina array failed to detect GR expression. Therefore, GR expression as determined by qPCR is annotated separately. Of the 10 control tissues, 8 were analyzed twice (technical duplicates annotated as A and B).