从细胞分裂模式角度及单细胞水平研究Sox2+上皮细胞在前列腺发育及癌变中的作用

Although it is believed that there are basal and/or luminal stem cells during prostatic development and tumorigenesis, whether they independently exist or both of them come from the basal stem cells is so far controversial. Our previous work suggested that in the mouse, the daughter Sox2+ luminal cell derived after an asymmetrical division of the basal stem cell is probably a prostate stem cell（Nature Comm 2014）and that in human prostate cancer hTERThigh/Numblow cells displayed the traits of cancer stem cells（Cancer Res, Clin Cancer Res 2017）. In the present study, we will employ several reporter transgenic mouse lines (Sox2CreER; RFPfl/fl、CK14CreER; RFPfl/fl、CK8CreER; RFPfl/fl) to perform lineage tracing experiments of the Sox2+ luminal cell to verify whether it is indeed derived after an asymmetrical division of a basal stem cell and possesses stem cell functions. In addition, prostate cancer mouse models （Pten mutant，H-Myc）will be used to determine if the Sox2+ luminal cell may act as cancer stem cells during tumorigenesis and development of androgen independence. Furthermore, single cell sequencing will be conducted to analyze the gene expression profiles among Sox2+ luminal cells and other epithelial cells including hTERThigh/Numblow cells, so to identify novel molecules that play important roles in formation of cancer stem cells and in tumorigenesis/ tumor progression.

前列腺基底干细胞和/或管腔干细胞是否独立存在，还是都来源于基底干细胞是重要课题。我们发现，由小鼠基底细胞不对称分裂产生的子代Sox2+管腔细胞可能是前列腺癌干细胞（Nature Comm 2014）；人前列腺癌hTERThigh及Numblow的细胞具有肿瘤干细胞特征（Cancer Res, Clin Cancer Res 2017）。本项目拟利用多种报告小鼠（Sox2CreER; RFPfl/fl、CK14CreER; RFPfl/fl、CK8CreER; RFPfl/fl），谱系追踪Sox2+管腔细胞，验证其来源于基底细胞的不对称分裂，并具有管腔干细胞功能；研究其在小鼠前列腺癌自发模型（Pten mutant，H-Myc）中是否起肿瘤干细胞作用，驱动雄性激素非依赖性；利用单细胞测序比较Sox2+管腔细胞群与其它细胞包括hTERThigh/Numblow的相关性，寻找功能调控关键因子。

前列腺癌是男性泌尿生殖系统常见的恶性肿瘤，但我们对其起源以及治疗后复发机制认识不足。本项目结合临床样本高通量测序，实验动物模型，分子功能实验系统研究了前列腺组织中的不同细胞亚群在前列腺癌发生发展以及治疗抵抗中的作用。在本课题的资助下，我们课题组取得了如下成果：1)明确了转录因子SOX2与前列腺癌激素治疗抵抗密切相关，并阐明了SOX2表达模式和前列腺癌基底细胞/腔细胞起源的关系。2)明确了Gremlin1，Numb等基因在前列腺癌中的表达模型以及作用机制，制备了一种特异性的抗Gremlin1单克隆抗体，并证明它对去雄抵抗性前列腺癌具有显著的抑制作用，并且与雄激素剥夺疗法具有协同作用。 3)在单细胞水平深入解析了激素治疗抵抗型前列腺癌的肿瘤微环境，揭示了肿瘤细胞基底细胞型/腔细胞型异质性，首次从单细胞角度证明腔细胞型肿瘤细胞是神经内分泌型前列腺癌的直接起源，并基于肿瘤细胞表型异质性建立了激素治疗抵抗型前列腺癌的分子分型。本项目研究成果有助于更全面地理解前列腺癌发生发展和对雄激素剥夺疗法抵抗的机制，并为肿瘤的预警、诊断和治疗提供了新的分子靶标和策略。