Pleiotropic functional properties of androgen receptor mutants in prostate cancer

The androgen receptor (AR) signaling pathway plays an important role during the development of the normal prostate gland, but also during the progression of prostate cancer on androgen ablation therapy. Mutations in the AR gene emerge to keep active the AR signaling pathway and to support prostate cancer cells growth and survival despite the low levels of circulating androgens. Indeed, mutations affecting the ligand binding domain (LBD) of the AR have been shown to generate so-called "promiscuous" receptors that present widened ligand specificity and allow the stimulation of these receptors by a larger spectrum of endogenous hormones. Another class of mutations, arising in the amino-terminal domain (NTD) of the receptor, modulate AR interactions with coregulators involved in cell proliferation regulation. Besides characteristics of these well-known types of mutations, the properties of other classes of AR mutants recently described in prostate cancer are currently under investigation. Most interestingly, in addition to their potential role in the mechanisms which allow prostate cancer cells to escape androgen ablation therapy, data suggest that certain AR mutations are present early in the natural history of the disease and may play a role in many aspects of prostate cancer progression. Surprisingly, singular truncated AR devoid of their carboxy-terminal end (CTE) region seem to exert specific paracrine effects and to induce a clonal cooperation with neighboring prostate cancer cells, which may facilitate both the invasion and metastasis processes. In this article, we review the functional properties of different classes of AR mutants and their potential impact on the natural history of prostate cancer. Hum Mutat 0, 1-14, 2008. (c) 2008 Wiley-Liss, Inc.     

Expression of neuroendocrine differentiation markers in lethal metastatic castration-resistant prostate cancer

Neuroendocrine differentiation (NED) is a common phenomenon in prostate cancer, and it has been associated with poor prognosis in some studies of primary prostate cancer. Incidence and patterns of NED in metastatic prostate cancer sites have not been examined widely. In this study, we studied expression of three commonly used markers of NED (chromogranin A, neuron specific enolase and synaptophysin) in 89 metastases from 31 men that died of castration-resistant prostate cancer and underwent rapid autopsy, and in 89 hormone-naïve primary tumors removed by radical prostatectomy. In addition, we examined NED association with androgen receptor, ERG and Ki-67 expression in metastatic tumor sites. Morphologically, 1 of 31 cases was classified as small cell carcinoma, and the remaining 30 were classified as usual prostate adenocarcinoma using a recently proposed classification of prostate cancers with NED. Metastases showed more expression of neuron specific enolase and synaptophysin compared to prostatectomies (6.3% of cells vs. 1.0%, p?<?0.001 and 4.0% vs. 0.4%, p?<?0.001, respectively). At least focal expression of one of the markers was seen in 78% of metastases. Strong expression was relatively uncommon, seen in 3/89 (chromogranin A), 8/89 (neuron specific enolase), and 5/89 (synaptophysin) metastases. Expression of chromogranin A and synaptophysin correlated with each other (r?=?0.64, p?<?0.001), but expression of neuron specific enolase did not correlate with the two other markers. Extent of NED varied significantly between different metastatic sites in individual patients. Absent androgen receptor expression was associated with strong expression of chromogranin A (p?=?.02) and neuron specific enolase (p?=?.02), but not with focal expression of any marker. No clear association was found between expression of NE markers and ERG or Ki-67. In conclusion, NED is a common and heterogeneous phenomenon in metastatic, castration-resistant prostate cancer. NED is more often present in castration-resistant prostate cancer compared to hormone-naïve disease, and it is associated with androgen receptor negativity. More research is needed to understand significance of NED in the progression of prostate cancer.     

Association of intraductal carcinoma of the prostate detected by initial histological specimen and neuroendocrine prostate cancer: A report of three cases

We present three cases of neuroendocrine prostate cancer (NEPC) and histologically investigate the association of intraductal carcinoma of the prostate (IDC-P) and NEPC. Case 1 was a 76-year-old man who had NEPC identified by repeated biopsy specimens when his prostate-specific antigen (PSA) level became elevated 8 years after the initiation of androgen deprivation therapy (ADT). Case 2 was a 70-year-old man who had NEPC detected when multiple bone metastases were found 3 years after the initiation of ADT. Case 3 was a 70-year-old man who was diagnosed with NEPC based on histological examination of transurethral resected specimens. The histological findings in these three cases showed mixed neuroendocrine carcinoma–acinar adenocarcinoma with various proportions of both components. In all three cases, the neuroendocrine carcinoma components were positive for synaptophysin and chromogranin A, whereas the adenocarcinoma components were positive for PSA and NKX3.1. When we retrospectively reviewed the initial hematoxylin and eosin-stained slides, IDC-P was detected in all three cases. Furthermore, we collected nine additional cases of NEPC and found that all six cases with initial biopsy specimens available had an IDC-P component. Detecting IDC-P on initial histological specimens of the prostate may predict transformation to NEPC.     

Tissue microarray analysis of neuroendocrine differentiation and its prognostic significance in breast cancer

The aim of this study was to detect neuroendocrine differentiation (NE), to determine its association with major clinicopathological parameters of breast cancer, and to study the prognostic significance of NE differentiation in a group of breast carcinomas by using tissue microarray (TMA) methodology. NE differentiation was studied by using 3 markers, synaptophysin (Syn), chromogranin A (ChA), and neuron-specific enolase (NSE) in a group of 334 patients with breast carcinoma. TMA blocks were made by using duplicate 0.6-mm-diameter tissue cores from each paraffin block. Results of immunostaining were scored on a 4-point scale, that is, as negative, weak, intermediate, and strong immunoreactivity. Positive staining of breast cancers for any of the 3 NE markers was detected in 19.5% of cases. Expression of a single marker was present in 16.2% of cases, and expression of 2 or 3 markers in combination was detected in 3.3% of cases. There was no statistically significant correlation of NE phenotype with tumor morphology, except mucinous carcinoma (3 of 6 cases positive), estrogen receptor, progesterone receptor, or nodal status. A weak correlation was noted between synaptophysin staining and higher tumor grade (P = 0.029). Analysis of disease-specific and overall survival based on up to 20 years of follow-up data showed a correlation between NSE expression and improved disease-specific (P = 0.043) and overall survival (P = 0.03) in univariate but not in multivariate analysis. The expression of Syn and ChA, as well as coexpression of multiple NE markers, had no prognostic significance.     

Expression of pepsinogen II with androgen and estrogen receptors in human prostate carcinoma

The expression of pepsinogen II (PG II), an aspartyl proteinase usually involved in the digestion of proteins in the stomach, was immunohistochemically investigated in conjunction with androgen (AR) and estrogen receptor (ER) status in prostate adenocarcinomas. Of a total of 38 samples obtained from radical prostatectomies, 23 tumors (60.5%) were positive for PG II and there was a significant positive correlation to the expression of AR but not to ER. Cells positive for PG II were localized mainly to the peripheral zones of tumorous glands which, in normal prostate, are negative, and in areas also expressing AR. In addition, a significant correlation between AR and ER was detected in the prostate carcinomas examined, which suggests a hormone-dependent status. On the basis of these results, PG II expression might be closely related to hormonal alterations associated with the development of prostate tumors.     

The androgen receptor co-activator CBP is up-regulated following androgen withdrawal and is highly expressed in advanced prostate cancer

The androgen receptor co-activator CREB (cAMP-response element binding protein)-binding protein (CBP) enhances androgen receptor activity after stimulation by androgenic hormones and androgen receptor antagonists. The aim of the present study was to investigate the regulation of CBP expression by steroid and peptide hormones in prostate cancer. For this purpose, LNCaP cells were treated with the synthetic androgen methyltrienolone (R1881), epidermal growth factor, insulin-like growth factor-I or interleukin-6 (IL-6). CBP protein and mRNA expression were studied by western blotting and real-time PCR, respectively. CBP expression was also investigated in tissue specimens obtained from 26 patients with therapy-resistant carcinoma of the prostate. In LNCaP cells, CBP protein was down-regulated by R1881 or IL-6. The non-steroidal anti-androgen bicalutamide antagonized the effects of R1881 and the Janus kinase inhibitor AG 490 reversed the effects of IL-6. In contrast, neither R1881 nor IL-6 caused any effect on CBP expression in the PC-3 cell line. In LNCaP cells, the inhibition of CBP expression by R1881 or IL-6 was also observed at the mRNA level. CBP protein was detected in all 26 specimens by immunohistochemistry. The results suggest that up-regulation of CBP during androgen ablation may be relevant to the failure of endocrine therapy in patients with prostate carcinoma.     

前列腺癌雄激素受体表达与细胞凋亡的关系

目的：探讨前列腺癌雄激素受体与细胞凋亡的关系及其生物学特性,方法：56例前列腺癌和20例良性前列腺增生症,应用免疫组化方法检测石蜡蜡包埋的组织切片中雄激素受体（AR）表达和应用原位末端标记技术（TUNEL）检测细胞凋亡指数（AI）。结果：AR在良恶性前列腺组织中的表达差异无显著性（P＞0．05）。AR和AI与前列腺癌Gleason分级无关。AI在前列腺癌组织中的表达明显高于良性前列腺增生症（P＜0．05）,AR阳性的前列腺癌AI亦明显高于AR阴性的前列腺癌。结论：前列腺癌组织中AR的表达可诱导其细胞凋亡,并对前列腺癌的功能性分类和内分泌治疗的疗效判断具有实用的临床意义。     

Immunohistochemical and ultrastructural features of neuroendocrine differentiated carcinomas of the prostate: an immunoelectron microscopic study

The purpose of this study was to further define the immunohistochemical and ultrastructural characteristics of neuroendocrine (NE) differentiated prostatic carcinomas. Seventy-seven specimens were obtained from prostatic carcinoma tumors during prostatectomy, transurethral resection of prostate or biopsy in 77 prostate cancer patients, and analyzed by immunohistochemical staining for chromogranin A (CgA). Nine of these tumors were also studied by elctron microscopy and 4 were examined by pre-embedding immunoelectron microscopy. CgA-stained cells were detected in 36 tumors (47%). Clinically advanced tumors or tumors with higher histological grades were associated with increased NE differentiation. Three of the tumors studied by electron microscopy contained cells showing unequivocal NE differentiation revealed by the presence of neurosecretory granules, while the poorly NE-differentiated malignant cells contained pleomorphic granules, which were lysosomal-like rather than NE-type granules. Immunoelectron microscopy demonstrated the presence of CgA immunoreactivity on the pleomorphic granules in the poorly differentiated malignant glands. This study suggests that NE-differentiated malignant cells in prostate cancer tissues may induce aggressive behavior in adjacent proliferating neoplastic cells via a paracrine mechanism.     

前列腺癌中巨嗜细胞抑制细胞因子-1基因的表达及意义

目的评估巨嗜细胞抑制细胞因子-1（MIC-1）在前列腺癌细胞系和前列腺癌组织中的表达情况，并明确其表达水平和临床病理学参数间的关系。方法用RT-PCR及免疫组化方法检测MIC-1在LNCaP、PC-3细胞系和前列腺癌组织中的表达。结果MIC-1在LNCaP细胞系中高表达，在前列腺癌组织中的表达水平明显高于增生和正常前列腺组织（P〈0．001）。MIC-1基因表达水平和前列腺癌临床分期、Gleason评分、PSA水平、前列腺体积以及患者年龄均无明显相关性。结论MIC-1蛋白可能将成为前列腺癌诊断新的肿瘤标记物。     

Chronic caffeine intake increases androgenic stimuli,epithelial cell proliferation and hyperplasia in rat ventral prostate

Coffee intake has been associated with a low risk of developing cancer, including prostate cancer, which is one of the most commonly diagnosed cancer in men. However, few studies have evaluated the chronic effects of caffeine, which is the most abundant methylxanthine in coffee, on prostate morphology and physiology. In the present study, we investigated the effects of chronic, low‐dose caffeine intake on rat prostate morphology from puberty to adulthood. Five‐week‐old male Wistar rats were randomized into two experimental groups: caffeine‐treated (20 ppm in drinking water, n = 12) and control (n = 12). The ventral and dorsolateral prostates were dissected, weighted and submitted to morphological, morphometrical and immunohistochemical analysis of cellular proliferation, apoptosis and androgen receptor (AR) tissue expression. The testosterone (T) and dihydrotestosterone (DHT) concentrations were measured in the plasma. Our results show that caffeine intake increased the concentrations of T and DHT, organ weight, epithelial cell proliferation and AR tissue expression in the ventral prostatic lobe. All the ventral prostates from the caffeine‐treated animals presented various degrees of epithelial and stromal hyperplasia. Our results suggest that chronic caffeine intake from puberty increases androgenic signalling and cell proliferation in the rat prostate gland and can be related to the development of benign prostatic hyperplasia.     

非小细胞肺癌中凋亡相关蛋白与伴神经内分泌分化表达的相关性

目的 检测非小细胞肺癌(non-small cell lung carcinoma,NSCLC)中凋亡相关蛋白与神经内分泌(neuroendocrine,NE)分化的表达,探讨其相关性.方法 采用免疫组织化学染色方法,检测NSCLC组织中survivin,bcl-2蛋白与NSE、Syn及CgA等蛋白的表达,并进行相关性作统计学分析.结果 113例NSCLC中,survivin、bcl-2阳性表达率分别为88.5%、58.4%;NSE、Syn和CgA蛋白阳性表达率分别为53.6%、6.2%和26.5%.伴NE分化者占21.2%,其survivin蛋白表达明显高于不伴NE分化组,差异有统计学意义.结论survivin、bcl-2蛋白表达上调可能在NSCLC发生发展中起重要作用.伴NE分化的NSCLC与表达阴性者相比,以survivin为代表的抗凋亡能力明显增强.     

Tyk2促进前列腺癌细胞系雄激素受体特异位点Tyr-267磷酸化

目的探讨JAK激酶家族成员Tyk2在雄激素受体(AR)磷酸化和前列腺癌细胞增殖中的作用。方法以LNCaP及LAPC-4细胞系为研究对象,在无雄激素条件下,用表皮生长因子(EGF)刺激,给予AIM-100/Baricitinib(INCB 028050)处理,免疫沉淀法和Western blot法检测AR磷酸化;将Tyk2 siRNA转染LNCaP及LAPC-4细胞系,用Western blot法检测沉默Tyk2对AR磷酸化的影响;用CCK-8试剂盒检测前列腺癌细胞增殖。结果 EGF诱导AR Tyr-267特异位点磷酸化并促进前列腺癌细胞增殖(P0.05);AIM-100抑制Ack1和Tyk2介导的LNCaP/LAPC-4细胞增殖(P0.05)和AR Tyr-267位点磷酸化;INCB抑制Tyk2磷酸化、AR Tyr-267位点磷酸化及LNCaP/LAPC-4细胞增殖(P0.05)。结论 Tyk2是EGF诱导AR Tyr-267特异位点磷酸化和前列腺癌细胞增殖的关键激酶,在前列腺癌发病过程中可能扮演重要角色。     

胃癌伴神经内分泌分化的研究进展

胃癌发生发展过程中,部分癌细胞会表达神经内分泌颗粒,出现神经内分泌分化现象。多数研究认为,神经内分泌（neuroendocrine,NE）细胞和上皮细胞均来自内胚层多潜能干细胞,是肿瘤发生过程中干细胞多向分化的结果。神经内分泌分化机制可能与Neuro D转录因子、突触间囊泡蛋白2、 menin蛋白、Reg Iv(Regenerating gene Iv)基因、p53的突变和bcl-2基因的表达有关。     

非小细胞肺癌生物学特性与神经内分泌分化的关系

目的：探讨非小细胞肺癌神经内分泌（neuroendocrine,NE)分化与肺癌生物学特性的关系。方法：采用免疫组化LSAB法检测有随访资料（8年）的53例非小细胞肺癌（non small cell lung carcinoma,NSCLC)神经内分泌标志。结果：NSCLC表达NSE、S－100蛋白、chromogranin A(CgA)和synaptophysin(Syn)阳性率分别为28．3％（15／53）、66．7％（39．53）、0／53和3．8％（2／53）。NSCLC伴NE分化与瘤体分期（Tstage)、治疗后肿瘤易复发和转移相关；有淋巴结转移的NSCLC患者3年和5年生存率低。结论：部分NSCLC伴NE分化，伴NE分化的NSCLC瘤体分期高、经综合治疗后肿瘤易复发和转移。有淋巴结转移的NSCLC患者预后差。     

GRP78 up-regulation is associated with androgen receptor status, Hsp70-Hsp90 client proteins and castrate-resistant prostate cancer

GRP78/BiP is a key member of the molecular chaperone heat shock protein (Hsp) 70 family. It has a critical role in prostate cancer (PC) including Pten loss‐driven carcinogenesis, but the molecular basis of this remains unclear. We investigated the effect of GRP78 and its putative client proteins, including androgen receptor (AR) in clinical PC. Expression of GRP78 and key Hsp70–hsp90 client proteins (HER2, HER3, AR and AKT) were studied in an incidence tissue microarray (TMA) of prostate cancer. The relationship of GRP78 and AR was further tested in in vitro cell models (LNCaP and its derived LNCaP‐CR subclone) and a matched TMA of hormone‐naïve (HNPC) and castrate‐resistant prostate cancer (CRPC). In vitro and in vivo expression of GRP78 and client proteins were assessed by western blotting and immunohistochemistry, respectively, using the weighted histoscore method. Significant co‐expression of GRP78, pAKT, HER2, HER3 and AR was observed in PC. Abnormal AR, GRP78 and pAKT expression have significant impact on patient survival. GRP78 expression in AR⁺ tumours was significantly higher than in AR^? tumours. In keeping with our clinical data, activation of AR by dihydrotestosterone (DHT) potently activated GRP78 expression in both LNCaP and LNCaP‐CR cells. For the first time, using a matched HNPC and CRPC TMA, enhanced cytoplasmic and membranous GRP78 expression was observed in CRPC. Future prospective studies are therefore warranted to validate GRP78 as prognostic marker and therapeutic target, in the context of the AR and pAKT status. In summary, GRP78 is co‐expressed with Hsp70–hsp90 client proteins. Up‐regulated expression of AR and GRP78 expression in untreated prostate cancer predicts a less favourable outcome. This points to the importance of understanding in the molecular interaction among AR, GRP78 and AKT. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Amplification of the androgen receptor gene is associated with P53 mutation in hormone-refractory recurrent prostate cancer

p53 protein expression of 30 hormone-refractory locally recurrent prostate cancers was compared with their matched untreated primary tumour specimens. In addition, androgen receptor (AR) gene amplification and p53 protein immunostaining were compared. p53 positivity increased during hormonal therapy from 17 per cent of the untreated primary tumours to 40 per cent of the hormone-refractory recurrences (p = 0·078). None of the p53-positive primary tumour specimens lost p53 positivity during hormonal therapy. Hormone-refractory recurrences with AR gene amplification more frequently (p = 0·0342) showed positive p53 immunostaining than tumours without AR gene amplification, 75 and 27 per cent, respectively. In summary, this study has shown that a cell clone with P53 mutation seems to be selected for during endocrine therapy and that positive p53 immunostaining correlates with AR gene amplification. These results suggest that inactivation of P53 may lead to genetic instability in a subset of prostate carcinomas enabling them to achieve properties, such as AR gene amplification, that allow them to grow in low levels of androgens and therefore cause tumour progression. Copyright © 1999 John Wiley & Sons, Ltd.     

Amplification of the androgen receptor gene in bone metastases from hormone-refractory prostate cancer

The aim of this study was to examine the prevalence of androgen receptor (AR) amplification in metastases to bone and other sites in patients with hormone-refractory prostate cancer (HRPC) and to compare these findings with those in pretreatment primary tumour samples from the same patients. Tissue from 24 patients with HRPC was available for study, together with 13 primary tumour specimens. AR gene amplification and copy number for X-chromosome were assessed by fluorescence in situ hybridization (FISH) using a SpectrumOrange-labelled probe at locus Xq11-13 for the AR gene and a SpectrumGreen-labelled alpha-satellite probe for the X-chromosome (Vysis, UK, Ltd.). A minimum of 20 nuclei were scored in each of three tumour areas by two independent observers. Samples from 18/24 patients with HRPC (12 bone marrow biopsies, three local tumour recurrences, and three lymph nodes) and nine primary tumour specimens were adequate for FISH analysis. Results were expressed as a mean ratio of AR gene copy number : mean X-chromosome number, with a ratio of greater than 1.5 defined as amplification. AR gene amplification was seen in 9/18 (50%) cases of HRPC and in none of the primary (untreated) tumour specimens (p = 0.0048, Fisher's exact test). For the 12 bone marrow samples, AR gene amplification occurred in 5/12 (38%) cases. Elevated copy number for chromosome X occurred in 3/18 (17%) HRPC and 4/9 (44%) matched primary tumours. This study shows for the first time that AR gene amplification can be demonstrated by FISH in bone metastases from HRPC patients. Because bone marrow biopsies can be obtained from most patients with HRPC, the findings provide a rational basis for the routine selection of patients who may respond more favourably to second-line anti-androgen therapy.     

利用RNA干涉技术研究雄激素受体在人前列腺癌细胞增殖中的作用

目的: 利用RNA干涉技术抑制雄激素受体(AR)的表达,研究AR在激素依赖性和激素非依赖性前列腺癌细胞增殖中的作用。方法: 设计、合成针对AR的4种不同的小干涉RNA(siRNA),连接到带有人H1启动子的腺病毒载体质粒pShuttle-H1-Ri中,构建成能产生AR-siRNA的质粒pShuttle-H1-Ri-AR,与能表达AR的质粒pcDNA-AR共转染HEK293细胞,Western blot 检测不同的siRNA对AR表达的抑制效率,选取抑制效率高的siRNA制备重组腺病毒,感染LNCap、C4-2B和CWR22Rv1 3种对雄激素有不同反应性的人前列腺癌细胞,采用Western blot 检测感染后细胞中AR的表达程度,并用MTT比色法测定细胞的增殖活性。结果: 4种siRNA都能抑制共转染AR的表达,用抑制效率高的siRNA制备重组腺病毒感染3种靶细胞后,均能特异性地抑制3种细胞中AR的表达,细胞的增殖活性也随之明显下降。结论: AR-siRNA通过抑制激素依赖性和激素非依赖性前列腺癌细胞中AR的表达,有效地抑制细胞的增殖,AR对维持激素依赖性和激素非依赖性前列腺癌细胞的增殖活性具有十分重要的作用,是治疗前列腺癌的重要靶分子。     

Immunodetection of androgen receptor in human urinary bladder cancer

We investigated the expression of androgen receptor (AR) protein in transitional cell carcinoma of human urinary bladder in paraffin-embedded sections of tumours obtained from nine patients with urinary bladder cancer treated by radical cystectomy. In addition, immunoblotting of AR was also performed on selected samples. Nuclear immunoreactivity of AR was found in seven of the nine urinary bladder cancers studied. AR showed variable staining intensity within a tumour. In the immunoblots, a 110 kDa AR signal was seen with anti-AR antibody, and faint bands of 90 and 60 kDa were also observed. Immunohistochemistry of p53 and c-erbB-2 was also carried out and compared with the distribution of AR. The high frequency of AR expression suggests a role for androgens in transitional cell carcinoma of human urinary bladder.     

Immunodetection of androgen receptor in human urinary bladder cancer

We investigated the expression of androgen receptor (AR) protein in transitional cell carcinoma of human urinary bladder in paraffin-embedded sections of tumours obtained from nine patients with urinary bladder cancer treated by radical cystectomy. In addition, immunoblotting of AR was also performed on selected samples. Nuclear immunoreactivity of AR was found in seven of the nine urinary bladder cancers studied. AR showed variable staining intensity within a tumour. In the immunoblots, a 110 kDa AR signal was seen with anti-AR antibody, and faint bands of 90 and 60 kDa were also observed. Immunohistochemistry of p53 and c-erbB-2 was also carried out and compared with the distribution of AR. The high frequency of AR expression suggests a role for androgens in transitional cell carcinoma of human urinary bladder.