Androgen receptor variants occur frequently in castration resistant prostate cancer metastases.
Androgen receptor variants occur frequently in castration resistant prostate cancer metastases.
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DOI：
10.1371/journal.pone.0027970
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Plymate SR
中科院分区：
文献类型：
--
作者：
Zhang X;Morrissey C;Sun S;Ketchandji M;Nelson PS;True LD;Vakar-Lopez F;Vessella RL;Plymate SR
虽然雄激素在去势抵抗性前列腺癌（CRPC）中减少，但转移瘤仍表达核雄激素受体（AR）和雄激素调节基因。我们最近报道了c端截断的本构活性AR剪接变体有助于CRPC的发展。由于无法获得检测所有c端截断AR变异的特异性抗体，我们的目的是开发一种评估前列腺癌（PCa）中AR变异的患病率和功能的方法。利用2种针对AR蛋白不同区域（N端或c端）的抗体，我们成功地证明了lucap86.2异种移植物中存在AR变异。为了评估人类PCa组织中AR变异的患病率，我们在组织微阵列上使用了这种方法，包括50例原发性PCa和162例转移性CRPC组织。RT-PCR用于确认AR变异。我们观察到CRPC中核c端AR染色显著降低，但原发性PCa中N-和c端AR核染色无差异。CRPC样品中c端染色减少对AR调控蛋白PSA和PSMA的表达影响不大。这些数据表明，基于我们使用N端和c端AR抗体区分核AR表达的能力，CRPC中AR变体的患病率有所增加。使用RT-PCR验证了这些发现。重要的是，在同一患者中，c端免疫反应性的丧失和AR变异的识别因转移部位的不同而不同。我们成功地开发了一种新的免疫组织化学方法，用于确定大量原发性PCa和转移性CRPC中AR变异的患病率。我们的研究结果显示了CRPC中c端截断AR剪接变异体的总体高频率和位点特异性AR丢失的快照，这可能有助于对AR靶向治疗的患者进行分层。
Although androgens are depleted in castration resistant prostate cancer (CRPC), metastases still express nuclear androgen receptor (AR) and androgen regulated genes. We recently reported that C-terminal truncated constitutively active AR splice variants contribute to CRPC development. Since specific antibodies detecting all C-terminal truncated AR variants are not available, our aim was to develop an approach to assess the prevalence and function of AR variants in prostate cancer (PCa). Using 2 antibodies against different regions of AR protein (N- or C-terminus), we successfully showed the existence of AR variant in the LuCaP 86.2 xenograft. To evaluate the prevalence of AR variants in human PCa tissue, we used this method on tissue microarrays including 50 primary PCa and 162 metastatic CRPC tissues. RT-PCR was used to confirm AR variants. We observed a significant decrease in nuclear C-terminal AR staining in CRPC but no difference between N- and C-terminal AR nuclear staining in primary PCa. The expression of the AR regulated proteins PSA and PSMA were marginally affected by the decrease in C-terminal staining in CRPC samples. These data suggest that there is an increase in the prevalence of AR variants in CRPC based on our ability to differentiate nuclear AR expression using N- and C-terminal AR antibodies. These findings were validated using RT-PCR. Importantly, the loss of C-terminal immunoreactivity and the identification of AR variants were different depending on the site of metastasis in the same patient. We successfully developed a novel immunohistochemical approach which was used to ascertain the prevalence of AR variants in a large number of primary PCa and metastatic CRPC. Our results showed a snapshot of overall high frequency of C-terminal truncated AR splice variants and site specific AR loss in CRPC, which could have utility in stratifying patients for AR targeted therapeutics.