Ack1: A Critical Regulator of Hormone-Refractory Prostate Cancer

摘要 雄激素受体(AR)在前列腺癌的发生发展中起重要作用。我们最近做了 证明AcK1(也称为TNK2)调节AR Tyr267-磷酸化 转录激活域。而多个酪氨酸激酶在转录水平上激活AR 作为AR激活的另一种模式，AcK1介导的AR Tyr267- 雄激素反应增强剂(ARE)和雄激素-AR募集中的磷酸化 独立的AR反应基因转录还不完全清楚。在这份赠款提案中，我们 证明激活的AcK1(pTyr284-AcK1)表达上调为前列腺癌 进展和这种激活与前列腺癌的生存呈负相关 病人。由于AcK1通过其磷酸化调节雄激素非依赖性AR活性 Tyr267，我们产生了特异性识别pTyr267-AR的抗体。都不是pTyr267-AR 抗雄激素对其表达或转录激活均有影响。 比卡鲁胺/卡索地尔和氟他胺。然而，AcK1的小分子抑制剂4-氨基-5，6- 联芳基呋喃并[2，3-d]嘧啶(YL3-026)不仅抑制AcK1的激活，而且能够 抑制pTyr267-AR磷酸化，与PSA、NKX3.1和TMPRS2启动子结合 抑制AR转录活性，表现为PSA基因表达显著降低。我们的 有证据表明，前列腺癌患者靶向AcK1激酶可能是 高效的治疗策略。在这份提案中，我们将确定AR Tyr267如何- 磷酸化调控雄激素非依赖性生长。此外，我们还将考察 AcK1抑制剂YL3-026抑制雄激素非依赖性转录和移植瘤 队形。此外，我们还将评估AcK1抑制剂YL3-026抑制AR的能力 Prob-AcK1中Tyr267的磷酸化与前列腺上皮内瘤形成 转基因小鼠。

ABSTRACT Androgen receptor (AR) plays a critical role in progression of prostate cancer. We have recently demonstrated that Ack1 (also known as TNK2) regulates AR Tyr267-phosphorylation within the transactivation domain. While AR transcriptional activation by multiple tyrosine kinases is emerging as an alternate mode of AR activation, the precise role of Ack1 mediated AR Tyr267- phosphorylation in AR recruitment to the androgen responsive enhancers (ARE) and androgen- independent AR-responsive gene transcription is not fully understood. In this grant proposal we demonstrate that activated Ack1(pTyr284-Ack1) expression is upregulated as prostate cancer progresses and this activation is inversely correlated with the survival of prostate cancer patients. Since Ack1 regulates androgen-independent AR activity by its phosphorylation at Tyr267, we generated antibodies that specifically recognize pTyr267-AR. Neither pTyr267-AR expression nor its transcriptional activation was affected by anti-androgens e.g. bicalutamide/casodex and flutamide. However, a small molecule inhibitor of Ack1, 4-Amino-5,6- biaryl-furo[2,3-d]pyrimidine (YL3-026) not only inhibited Ack1 activation, but was able to suppress pTyr267-AR phosphorylation, binding to PSA, NKX3.1 and TMPRS2 promoters and inhibit AR transcription activity as seen by significant decrease in PSA gene expression. Our evidence indicates that targeting Ack1 kinase in prostate cancer patients could therefore be highly effective therapeutic strategy. In this proposal we will determine how AR Tyr267- phosphorylation regulates Androgen-Independent growth. Further, we will examine the ability of Ack1 inhibitor, YL3-026, to suppress androgen-independent transcription and xenograft tumor formation. Moreover, we will assess the ability of Ack1 inhibitor YL3-026 to suppress AR Tyr267-phosphorylation and prostatic intraepithelial neoplasia (PINs) formation in Prob-Ack1 transgenic mice.