HOXD13在去势抵抗性前列腺癌转移和神经内分泌分化中的作用

Castration-resistant prostate cancer (CRPC) subsequent to androgen receptor (AR)-targeted therapy is frequently transformed into neuroendocrine prostate cancer (NEPC). Previosus studies indicated that NEPC is a highly aggressive subtype of prostate cancer characterized by molecular features of low to absent AR expression, and clinically manifested with visceral or large soft tissue metastatic disease, poor response to current treatments. Despite recent progress, the underlying mechanism for CRPC developed into NEPC remains to be defined. Our studies indicated that the mouse habouring prostate-specific POT1 (Protection of telomeres)/Pten/P53 triple genes deletion manifested the disease progression from CRPC into NEPC. Taken advantage of this disease model, we untilize differential gene expression analysis and identified that HOXD13 might play critical roles during this disease process. In this application, we propose to utilize the genetically engineered mouse models (Knockout or conditional overexpression approach) together with PCA cell lines to elucidate the role of HOXD13 in mediating local CRPC metastasis and neuroendocrine differentiation, as well as the function of HOXD13 in the regualtion of AR signaling axis and NED associated genes. In addition, we would explore the genome and transcriptom features of metastatic NEPC using deep sequencing to access the clinical releveance of HOXD13 mediated signaling circuits with CRPC trans-differentiation and progression. Thus, success accomplishment of the proposed goals will provide new insights on the etiology of this disease and develop new approaches against NEPC.

去势抵抗性前列腺癌（CRPC）靶向雄激素受体（AR）治疗后易转化为神经内分泌前列腺癌（NEPC），临床表现为腹腔脏器和软组织转移，无有效治疗方式，预后极差，分子特征表现为低或不表达AR，目前该转化过程的分子机制尚不清楚。课题组前期建立了端粒保护蛋白POT1联合Pten/P53前列腺特异基因敲除小鼠模型，发现该模型可以体内模拟局限性CRPC进展为转移性NEPC的临床进程，差异表达基因分析和功能验证提示HOXD13在该转化过程中可能发挥重要作用。本项目拟在细胞学和整体动物水平，利用HOXD13基因敲除和过表达模型，研究HOXD13在CRPC转移和神经内分泌分化（NED）中的作用，探讨HOXD13对AR信号通路和NED相关基因的调控；对临床组织标本进行深度测序，分析验证HOXD13基因作用通路和CRPC进展转移及NED的相关性。本项目的完成将为NEPC的分子诊断和靶向治疗提供新的思路。

神经内分泌分化（NED）是前列腺肿瘤内分泌治疗抵抗的重要原因之一，其发生机制目前尚不明确。课题组通过构建模拟这一临床进程的转基因小鼠模型（端粒保护蛋白POT1联合Pten/P53前列腺特异基因敲除），对肿瘤组织与癌旁正常组织进行高通量RNA测序分析，将两组差异表达基因与前列腺肿瘤临床数据库患者标本表达水平进行比对，筛选出HOXD13这一研究靶点。进一步通过构建HOXD13基因敲除和过表达前列腺癌细胞模型，明确HOXD13低表达能够促进去势抵抗型前列腺癌细胞系在体外及体内的恶性进展。进一步对细胞系模型进行RNA测序分析，发现HOXD13高表达细胞系中EMT相关抑制基因显著富集。通过qPCR及荧光素酶报告实验进一步明确，TGF-β信号通路中关键分子SMAD1是HOXD13直接负调控的下游靶分子。HOXD13过表达能够抵抗BMP４诱导EMT的发生，且回补SMAD1能够挽救HOXD13过表达前列腺癌细胞的恶性表型。因此，HOXD13在去势抵抗前列腺癌进展转移中起到重要的抑癌作用。