Mechanism and oncogenic role of lysine demethylase KDM5B in prostate cancer

摘要 前列腺癌(PCa)是美国男性最主要的威胁生命的恶性肿瘤，其发病率不成比例。 非洲裔美国人(AA)比其他族裔人口更高，这突显了解码 并开发新的有效治疗方法来治疗前列腺癌。尽管有雄激素- 剥夺疗法，复发发生在许多前列腺癌患者，他们最终仍然死亡。启蒙和启蒙 PCa的进展是由继发于遗传和转录因子的多条致癌途径的失调推动的 癌基因和肿瘤抑制基因的表观遗传学改变。PTEN(磷酸酶和张力同系物 在10号染色体上缺失)在各种人类癌症中频繁缺失和/或突变。PTEN的丢失 AKT-mTOR、Skp2、转化生长因子-β和雄激素受体(AR)信号的异常导致癌症 小路。KDM5B(赖氨酸去甲基酶5B，又称JARID1B)，一个含有JmjC结构域的H3K4组蛋白 去甲基酶激活FOXA1的基因表达，FOXA1是AR功能和信号转导的关键辅助因子。 KDM5B的异常升高常见于包括晚期前列腺癌在内的人类癌症中。FOXA1突变是 AA PCA样本比高加索美国人(CA)PCA样本高4倍，突显出 KDM5B/FOXA1在PCa差异中的重要性。然而，KDM5B的作用机制和贡献 前列腺癌的发生仍然难以捉摸。我们最近展示了KDM5B在 Pten/Trp53突变小鼠的前列腺癌及其水平受Skp2和TRAF6的调节 泛素化。我们的初步数据显示，AA PCA样本的KDM5B高于CA PCA样本 样本。此外，PTEN缺失会导致KDM5B在小鼠体内的表达增加，KDM5B基因敲除(KO) 降低PCa细胞中FOXA1和AR的水平。在本提案的目标1中，我们将调查 KDM5B在PTEN缺失驱动的前列腺癌发生中的作用基因工程小鼠的应用 模型，我们将从Pten和Kdm5b小鼠中产生Pten/Kdm5b双突变，并确定 Kdm5b缺乏对Pten缺失小鼠肿瘤进展的抑制作用。在目标2中，我们将调查 KDM5B信号网络在前列腺癌中的分子机制我们将定义KDM5B靶基因 芯片法检测KDM5B泛素化和突变，以及PTEN-AKT、Skp2和TRAF6对KDM5B泛素化和突变的调控 KDM5B修饰与人前列腺癌细胞株EZH2、FOXA1和AR信号通路的相关性 (PC3、LNCaP、C4-2B和MDA PCA 2b)。在目标3中，我们将评估KDM5B抑制对前列腺癌的影响 C4-2B和丙二醛Pca 2b细胞的生长及其对Pca差异的影响。我们将对影响进行评估 KDM5B KO及其化合物对前列腺癌移植瘤生长的抑制作用 Luc/Pten小鼠。这项提议的结果应该为我们提供有价值的洞察机制 前列腺癌的表观遗传学改变，以及控制前列腺癌的新治疗策略的潜在发展 成长。这项研究应该会给所有的PCa患者带来巨大的好处，减少/消除癌症差异。

Abstract Prostate cancer (PCa) is the leading life-threatening malignancy in American men and is disproportionally higher in African Americans (AAs) than other ethnic populations, underscoring a need to decode the underlying mechanism and to develop new and effective therapies to cure PCa. Despite androgen- deprivation therapy, relapse occurs in many PCa patients who eventually still die. The initiation and progression of PCa are driven by dysregulation of multiple oncogenic pathways secondary to genetic and epigenetic alterations of oncogenes and tumor suppressors. PTEN (phosphatase and tension homolog deleted on chromosome ten) is frequently deleted and/or mutated in various human cancers. Loss of PTEN leads to cancers with the aberration of AKT-mTOR, SKP2, TGF-β, and androgen receptor (AR) signaling pathways. KDM5B (lysine demethylase 5B, also named JARID1B), a JmjC domain- containing H3K4 histone demethylase, activates the gene expression of FOXA1, a crucial co-factor for AR function and signaling. Aberrant elevation of KDM5B is often found in human cancers including advanced PCa. FOXA1 mutation is 4-fold higher in AA PCa samples as compared to Caucasian American (CA) PCa samples, underscoring the importance of KDM5B/FOXA1 in PCa disparities. However, the mechanism and contributions of KDM5B to prostate tumorigenesis remain elusive. We recently demonstrated that KDM5B is noticeably increased in prostate tumors of Pten/Trp53 mutant mice, and that its levels are regulated by SKP2 and TRAF6 through ubiquitination. Our preliminary data reveal that KDM5B is higher in AA PCa samples than in CA PCa samples. In addition, PTEN loss results in an increase of KDM5B in mice, and KDM5B knockout (KO) decreased the levels of FOXA1 and AR in PCa cells. In aim 1 of this proposal, we will investigate the role of KDM5B in PTEN-null driven prostate tumorigenesis. With application of genetically-engineered mouse models, we will generate Pten/Kdm5b double mutants from Pten and Kdm5b mice, and define the effects of Kdm5b deficiency on the suppression of tumor progression in Pten-null mice. In aim 2, we will investigate the molecular mechanisms of KDM5B signaling network in prostate cancer. We will define KDM5B target gene by ChIP assay, KDM5B ubiquitination and mutation, its regulation by PTEN-AKT, SKP2 and TRAF6, and the relevance of KDM5B modification on EZH2, FOXA1, and AR signaling pathways using human PCa cell lines (PC3, LNCaP, C4-2B, and MDA PCa 2b). In aim 3, we will assess the effects of KDM5B inhibition on PCa growth of C4-2B and MDA PCa 2b cells, and its implications on PCa disparities. We will evaluate the impact of KDM5B KO and inhibition with compounds on the suppression of prostate tumor growth in xenografts and Luc/Pten mice. Results from this proposal should provide valuable insights into the mechanisms of epigenetic alterations in PCa, and a potential development of a novel therapeutic strategy to control PCa growth. This study should bring great benefit to all PCa patients and reduce/eliminate cancer disparities.