Distribution of a single nucleotide polymorphism on codon 211 of the androgen receptor gene and its correlation with human renal cell cancer in Japanese patients

Increased Expression of Androgen Receptor mRNA in Human Renal Cell Carcinoma Cells is Associated with Poor Prognosis in Patients with Localized Renal Cell Carcinoma

PURPOSE

The role of androgen receptor in renal cell carcinoma is not well understood. In this study the correlation between androgen receptor mRNA expression and clinicopathological features in patients with localized renal cell carcinoma was investigated. Additionally, human renal cell carcinoma cell lines were examined for the presence and effect of androgen receptor.

MATERIALS AND METHODS

Androgen receptor mRNA expression was evaluated by quantitative real-time polymerase chain reaction in 115 tumor samples from patients with primary pathological stage T1 or T2 (pT1/pT2) renal cell carcinoma and 57 specimens of corresponding normal kidney tissue. Reverse transcriptase-polymerase chain reaction and Western blot were done to examine the expression of androgen receptor in human renal cell carcinoma cell lines. Effects on cellular proliferation were investigated after activating and blocking androgen signaling in tissue culture.

RESULTS

Androgen receptor mRNA expression levels were significantly higher in patients with pT2 tumors than in those with pT1 tumors (p = 0.011). Kaplan-Meier estimates revealed significant differences in time to progression and cancer specific survival between low and high androgen receptor mRNA expression groups regardless of gender. Multivariate Cox regression analysis demonstrated that the level of androgen receptor expression was an independent predictor of cancer specific survival (HR 15.546, 95% CI 1.320-183.131, p = 0.029). In tissue culture treatment with dihydrotestosterone caused proliferation in androgen receptor positive cell lines while enzalutamide resulted in reduced cell viability in a dose dependent manner.

CONCLUSIONS

In patients with localized renal cell carcinoma the androgen receptor mRNA expression level is associated with prognosis. In addition, cell culture data suggest that enzalutamide may have an effect in limiting the growth of androgen receptor positive renal cell carcinoma.

Polymorphisms in androgen signaling pathway predisposing to prostate cancer

Prostate cancer is the most frequent male malignancy diagnosed in western countries and androgens are known to mediate key physiological processes in prostate tissue. Since endogenous androgens have long been considered to be risk factors for prostate cancer, genes involved in androgen biosynthesis and metabolism have been extensively studied. In this review, association of androgen pathway genes, their polymorphic sites and risk of prostate cancer in different ethnic backgrounds is addressed together with their use to predict susceptibility and clinical outcomes of prostate cancer patients. The effect of the polymorphisms seems vary in different patients, populations and ethnic backgrounds. To date it is evident that the association between androgen pathway gene polymorphisms and prostate cancer risk is complex and many of the results are characterized by irreproducibility, which can be attributed to a variety of biological, statistical and technical reasons. In the future, with increasing knowledge, developing technologies and new genomic biomarkers it likely becomes possible to better estimate the risk of prostate cancer, and distinguish indolent disease from aggressive based on molecular profiling, and the analysis of gene-gene and gene-environment interactions.

Association between genetic polymorphisms in androgen receptor gene and the risk of preeclampsia in Korean women

PURPOSE

To investigate associations between the androgen receptor (AR) polymorphisms as CAG repeats, GGC repeats and c.211G>A polymorphism and the risk of preeclampsia.

METHODS

The AR polymorphisms were experienced in 184 preeclamptic patients and 190 normal pregnancies and analyzed by multiple logistic regression.

RESULTS

Women with GGC repeats>16 were more frequently observed in preeclampsia, compared to those with GGC repeats≤16 [adjOR (95% CI): 3.64 (1.71-6.23)]. However, no significant differences were observed between the two groups with respect to CAG repeats. The genotypic and allelic frequencies of c.211G>A variant were significantly higher in cases than in controls (P < 0.05 for both). In the combined distribution of these polymorphisms, the highest risk of preeclampsia was found among women with the haplotype as CAG > 20/GA/GGC >16 [adjOR (95% CI): 4.26 (1.92-12.23)].

CONCLUSIONS

Our findings suggest that longer GGC repeats and c.211G>A variant in the AR gene are associated with increased susceptibility to the risk of preeclampsia.

Expressions of androgen receptor and its co-regulators in carcinoma ex pleomorphic adenoma of salivary gland

AIMS

Androgen receptor (AR) signalling is involved in cancer progression. The expression of AR has been reported in carcinoma ex pleomorphic adenoma (CXPA) of salivary gland, however AR gene status and the expressions of cofactors for AR signalling have not been investigated. The aims of this study were to investigate the expressions of each of the molecules that contribute to AR activation with or without ligands in CXPA. In addition, AR gene amplification and single-nucleotide polymorphism were investigated.

METHODS

Ten cases of CXPA and 23 cases of pleomorphic adenomas (PA) of the salivary glands were immunostained for the AR co-regulators (SRC1, p300, and NCoR1) and the signalling molecules involved in the ligand-independent pathway (i.e., HER-2/neu and STAT3). AR gene amplification and single-nucleotide polymorphism were investigated by dual-coloured fluorescent in situ hybridisation and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), respectively.

RESULTS

AR expression was observed in nine of 10 cases of CXPA and in 30.4% of PA cases, a statistically significant difference. The expression, with low or high intensity, of HER-2/neu and STAT3 was more frequent in CXPA (6/10 and 9/10, respectively) than in PA (0% and 46.7%). The expression of co-activators was also stronger, though only slightly, in CXPA than in PA. The gain of chromosome X and AR gene amplification were not observed in any CXPA or PA cases, and the G --> A allele in codon 211 was detected in only one case (a CXPA).

CONCLUSIONS

These results suggest that although AR may be activated in the pathway with or without ligands, the expression of co-regulators and AR gene aberrations are not involved in the carcinogenesis of CXPA.

Genomic biomarkers, androgen pathway and prostate cancer

Prostate cancer is the most frequent male malignancy diagnosed in western countries and the second leading cause of cancer-related deaths. The growth and function of the prostate gland depends on androgens. Owing to the importance of androgens in prostate development, genes involved in androgen biosynthesis and metabolism have been extensively studied. In this review, we address recent progress toward the use of inherited and acquired genetic variants to predict susceptibility and clinical outcomes of prostate cancer patients. Many of these genetic variants involve several genes related to the biosynthesis and metabolism of androgens, such as steroid-5-α-reductase, α polypeptide 2 (SRD5A2), cytochrome P450 (CYP)19A1, CYP17A1, hydroxy-δ-5-steroid dehydrogenase, 3 β- and steroid δ-isomerase 2 (HSD3B2) and androgen receptor (AR). With increasing knowledge, it may be possible to distinguish indolent from aggressive prostate tumors by molecular fingerprinting. Furthermore, with the emergence of new investigative tools, such as microarray platforms and comparative genomic hybridization (CGH) array, a variety of new genomic biomarkers will be available in the future to provide accurate prognostic and monitoring solutions for individualized patient care.

An unexpected wide population variation of the G1733A polymorphism of the androgen receptor gene: Data on the Mediterranean region

The androgen receptor (AR) has been proposed as a candidate gene for several cancers (breast, prostate, uterine endometrium, colon, and esophagus). Ethnicity is considered an associated risk factor for some of these cancers. Several case-control genetic studies have been focused in samples of the main ethnic groups, but little is known about the distribution of risk polymorphisms in current populations with accurate ethnic and/or geographic origins. The A allele of the G1733A polymorphism of the AR gene has been associated with increased risk of prostate cancer. We provide data from this marker in 12 samples from 7 Mediterranean countries such as Spain, Italy (Sardinia), Greece, Turkey, Morocco, Algeria, and Egypt. A sample from Ivory Coast has also been analyzed. The A allele distribution shows a frequency in the Ivory Coast population (65.17%) that contrasts with the low values found in Northern Mediterraneans (mean average value of 13.98%). North African populations present two-times higher frequencies (average value of 27.19%) than Europeans. The wide population variation range found for the A allele strengthens the potential interest of further screening as a baseline to the design of future preventive and population health programs.