雄激素受体非依赖的管腔祖细胞在神经内分泌型前列腺癌发生的作用及机制研究

Second-generation androgen deprivation therapy (ADT), which targets intratumoral androgen biosynthesis or androgen receptor (AR) pathway, remains as the major treatment for castration-resistant prostate cancer (CRPC). Unluckily, one-third of CRPC patients demonstrate primary resistance to second-generation ADT, whereas the remaining patients eventually progress on an AR-independent disease after the treatment. Notably, certain CRPCs undergo neuroendocrine differentiation (NED) upon ADT, leading to the formation of neuroendocrine prostate cancer (NEPC) that is extremely lethal to the patients. However, the cell of origin as well as the molecular properties that enable NEPC formation remain unclear. In preliminary studies, we have demonstrated that 1) an AR-independent prostate luminal progenitor population called CARNs selectively express CRPC-NED-related genes upon AR deletion; 2) Pten deletion and mutated Kras activation in AR-deleted CARNs causes the formation of CRPC with focal NED; 3) IL-8 is the most differentially expressed upregulated gene in AR-deleted CARNs signature; 4) the identification of 34 novel genes from the AR-deleted CARNs signature that show gene amplification in >40% CRPC-NED specimen in a published patient cohort; and 5) the optimization of tissue recombination and organoid assays for cell of origin experiment and functional analyses of various candidate genes. Based on these preliminary results, we hypothesize that CARNs represent a cell of origin for NEPC upon loss of AR and oncogenic transformation with key drivers for NED, and that genetic alterations in AR-deleted CARNs predisposes them to generate NEPC upon treatment with ADT. In the proposed studies, we will use state-of-art genetically engineered mouse model, newly developed adherent lines from prostate luminal progenitors, novel tissue recombination and organoid assays to investigate 1) the ability of prostate luminal progenitors, CARNs to serve as the cell of origin for NEPCs upon loss of AR; 2) the role of IL-8 in prostate luminal progenitors-induced NED-related gene expression and NEPCs initiation upon loss of AR; and 3) the NED-driving ability and prognostic significance of novel differential expressed genes in AR-deleted prostate luminal progenitors in CRPC. Taken together, elucidation of the role of prostate luminal progenitors to serve as the cellular origin for NEPC upon loss of AR as well as their intrinsic molecular characteristics that enable NED should provide novel and timely insights into the development of NEPCs. Consequently, targeting the intrinsic AR-independent prostate luminal progenitor population and their molecular properties may serve as novel treatment strategies to overcome resistance to second-generation ADT.

第二代雄激素剥夺法（ADT）是去势抵抗型前列腺癌（CRPC）的主要治疗方法。不幸的是，几乎所有CRPC在ADT治疗后，最终发展成雄激素受体（AR）非依赖性疾病。部分CRPC通过神经内分泌分化（NED），进展成神经内分泌型前列腺癌（NEPC）。然而，NEPC起源细胞的身份及分子特征亟待深入研究。我们前期研究发现，前列腺管腔祖细胞，CARNs，在AR缺失后表达CRPC-NED相关的基因，并在致癌转化后形成局灶性NED肿瘤，这预示着CARNs作为NEPC起源细胞的潜能。在本项目中，我们将探究CARNs在AR缺失后作为NEPC起源细胞的能力；评估IL-8在维持AR缺失CARNs所表达的NED相关基因的作用及其作为NEPC起源细胞的能力；和探索从AR缺失CARNs筛选出的候选基因的NED驱动能力及其对第二代ADT治疗的预后意义。综上所述，本研究将为克服第二代ADT耐药问题提供全新治疗方案和靶标。

近年来，第二代雄激素剥夺疗法已成为去势抵抗型前列腺癌（CRPC）的主要治疗方案。不幸的是，大多数CRPC最终会发展成雄激素受体（AR）非依赖型前列腺癌，其中包括表现出高增殖、高侵袭并伴随神经内分泌分化（NED）特征的神经内分泌前列腺癌（NEPC）。因此，阐明 NEPC的启动机制是一个亟待解决的临床问题，以为患者确定新的治疗策略。..在此项目中，我们探究了前列腺管腔祖细胞亚群CARNs作为NEPC起源细胞的潜能。首先，我们建立了全新的NPp53K基因工程小鼠模型（GEMM），能在去势和Tamoxifen灌注后在CARNs中特异性敲除Pten和Trp53及激活KrasG12D。由于CARN-NPp53K肿瘤的高度侵袭性，携带这些肿瘤的小鼠在Tamoxifen诱导4 至 6 周后便死亡。过后，我们建立了与CARN-NPp53K肿瘤表型相一致的类器官，包括含有少量表达NED标记物的细胞。值得一提的是，这些类器官能在重新移植到免疫完整小鼠体内后形成具备上皮-间质转化和NED特征的同种移植物（allograft）。此外，我们发现IL-8小鼠同源基因Cxcl1和Cxcl2及与过氧化物酶体调调控因子PEX14相关的自噬机制，有可能在NEPC发生发展中扮演着重要的角色。通过单细胞转录组测序，我们成功鉴定出CARN-NPp53K肿瘤中各种上皮和基质细胞亚群。同时，我们也发现Enzalutamide和自噬抑制剂组合治疗和HSP90抑制剂Onalespib可以有效抑制CARN-NPp53K类器官的活力。然而，CARN-NPp53K allograft对Onalespib产生抗药并显示Lc3b的高表达，预示着基质细胞亚群参与维持肿瘤细胞的自噬活性进而导致Onalespib耐药。..终上所述，我们的 GEMM-类器官-allograft研究策略证实了CARNs作为NEPC起源细胞的能力；而CARN-NPp53K肿瘤中一个具备免疫逃逸能力的细胞亚群可能在NEPC发生发展中扮演着重要的角色。此外，CARN-NPp53K类器官和allograft的不同治疗反应预示了肿瘤微环境在调控NEPC耐药的重要性。因此，靶向癌转化CARN生成的肿瘤细胞亚群和/或相关基质细胞可作为治疗NEPC的全新策略。