Androgen receptor signals regulate UDP‐glucuronosyltransferases in the urinary bladder: A potential mechanism of androgen‐induced bladder carcinogenesis

Abstract

UDP-glucuronosyltransferases (UGTs), major phase II drug metabolism enzymes, play an important role in urinary bladder cancer initiation by detoxifying carcinogens. We aimed to determine if androgens regulate UGT expression via the androgen receptor (AR) pathway in the bladder. Real-time reverse transcription-polymerase chain reaction and Western blot analyses were used to assess UGT1A levels in the normal urothelium SVHUC cell line stably expressed with AR and in bladder tissues from AR knockout (ARKO) and castrated male mice. Immunohistochemistry was also performed in radical cystectomy specimens. Dihydrotestosterone (DHT) treatment in SVHUC-AR reduced mRNA expression of all the UGT1A subtypes (19-75% decrease), and hydroxyflutamide antagonized the DHT effects. In contrast, DHT showed only marginal effects on UGT1A expression in SVHUC-Vector. Of note were higher expression levels of UGT1As in SVHUC-Vector than in SVHUC-AR. In ARKO mice, all the Ugt1a subtypes were up-regulated, compared to wild-type littermates. In wild-type male mice, castration increased the expression of Ugt1a8, Ugt1a9, and Ugt1a10. Additionally, wild-type female mice had higher levels of Ugt1a than wild-type males. Immunohistochemical studies showed strong (3+) UGT1A staining in 11/24 (46%) cancer tissues, which was significantly lower than in corresponding benign tissues [17/18 (94%) cases (P = 0.0009)]. These results suggest that androgen-mediated AR signals promote bladder carcinogenesis by down-regulating the expression of UGTs in the bladder.

FGFR3 Translocations in Bladder Cancer: Differential Sensitivity to HSP90 Inhibition Based on Drug Metabolism

“…Interestingly, the UGT1A gene cluster has been identified as a novel susceptibility locus for bladder cancer using genome-wide association studies (38). Furthermore, experimental evidence has shown that UGT1A expression becomes downregulated during bladder cancer progression in animal models (39), consistent with the hypothesis that UGT variants mapping to this region may provide a protective, tumor-suppressive function in bladder cells (40). FGFR3 fusion protein expression is likely to be an important biomarker to aid in patient selection when evaluating novel bladder cancer treatments, due to an increased susceptibility of fusion-bearing tumor cells to targeted FGFR therapies (9).…”

Loss of GATA3 in bladder cancer promotes cell migration and invasion

“…Real-time PCR was then performed in 15 μl system by using SYBR GreenER qPCR SuperMix for iCycler (Invitrogen), as described previously. 31,38 The primer sequences are given as below: GATA3 (forward, 5′-CAGCCTTCGC TTGGGCTTAA T-3′; reverse, 5′-GATGGCAGGC TCAGTGATGT C-3′), VEGF (forward, 5′-CTGTACCTCC ACCATGCCAA G-3′; reverse, 5′-GGTACTCCTG GAAGATGTCC ACC-3′), MMP-2 (forward, 5′-TACAGGATCA TTGGCTACAC ACC-3′; reverse, 5′-GGTCACATCG CTCCAGACT-3′), and MMP-9 (forward, 5′-TGTACCGCTA TGGTTACACT CG-3′; reverse, 5′-GGCAGGGACA GTTGCTTCT-3′). GAPDH (forward, 5′-AAGGTGAAGG TCGGAGTCAA C-3′; reverse, 5′-GGGGTCATTG ATGGCAACAA TA-3′) was used as an internal control.…”

Androgen activates β-catenin signaling in bladder cancer cells

“…Bladder tissue microarray (TMA) was constructed from 24 formalin-fixed paraffin-embedded cystectomy specimens retrieved from the Surgical Pathology archives, as described previously (Zheng et al 2011, Izumi et al 2013. Appropriate approval from the Institutional Review Board of the University of Rochester Medical Center was obtained before construction and use of the TMA.…”

“…Immunohistochemical staining was performed on the sections (5 mm thick) from the bladder TMA, as described previously (Zheng et al 2011, Izumi et al 2013, with minor modifications. Briefly, tissues were deparaffinized in xylene, rehydrated in a graded ethanol series, and incubated in 3% hydrogen peroxide to block endogenous peroxidase.…”