MP88-17 IMMUNOHISTOCHEMISTRY OF ANDROGEN RECEPTOR AND ESTROGEN RECEPTOR-β IN BLADDER CANCER AS PREDICTORS OF CHEMOSENSITIVITY

Abstract

INTRODUCTION AND OBJECTIVES: Recent evidence not only has indicated a critical role of AR signals in bladder cancer development but has also suggested the involvement of GR signals in tumor outgrowth [e.g. stimulation of cell proliferation by dexamethasone (DEX), suppression of cell invasion by DEX, predonisone (PRED), or corticosterone]. Nonetheless, it remains unclear whether GR ligands affect urothelial tumorigenesis. Meanwhile, CpdA is known to function as not only a GR modulator inducing GR transrepression but also an AR antagonist. In this study, we assessed the effect of GR ligands including CpdA on neoplastic transformation of urothelial cells. METHODS: A control subline of bladder cancer UMUC3 [UMUC3-control-short hairpin RNA (shRNA)] and its GR knockdown subline (UMUC3-GR-shRNA) were implanted into mouse flanks. The SVHUC normal urothelial cell line and that stably expressing wild-type AR or GR-shRNA were exposed to a chemical carcinogen 3-methylcholanthrene (MCA) 3 times and subsequently cultured for 6 weeks in the presence or absence of 11 pure glucocorticoids, CpdA, an antiandrogen hydroxyflutamide (HF), and an GR antagosist RU486, followed by cell proliferation assay and plate/soft agar colony formation assays to assess neoplastic transformation. RESULTS: Tumor formation as an end point was significantly (P<0.001) delayed in control UMUC3 xenograft-bearing mice, compared with GR knockdown xenografts. In SVHUC cells (GR-positive/AR-negative) exposed to MCA, only PRED and CpdA significantly prevented neoplastic transformation, which was abolished by RU486. In MCA-SVHUC-AR cells (GR/AR-positive), HF treatment also resulted in inhbition of neoplastic transformation, but the effect of CpdA (67% decrease in colony formation) was significantly stronger than that of HF (42% decrease) or PRED (42% decrease). In MCA-SVHUC-GR-shRNA cells (GR/AR-negative), CpdA, HF, and all other glucocorticoids failed to inhibit neoplastic transformation. In addition, among the GR ligands tested, CpdA most significantly reduced the expression of oncogenes, such as c-fos and c-jun, and induced that of UGT1A known to prevent urothelial tumorigenesis via detoxifying carcinogens in MCA-SVHUC cells. CONCLUSIONS: GR signaling appears to play an inhibitory role in urothelial tumorigenesis. Our results also suggest that CpdA via both GR and AR pathways more strongly prevents neoplastic transformation of urothelial cells than other glucocorticoids/pure GR ligands or AR antagonists.