Epithelial Transcription Factor FOXA1 Regulates Prostate Cancer Immune Response
Epithelial Transcription Factor FOXA1 Regulates Prostate Cancer Immune Response
复制标题
DOI：
10.1210/jendso/bvab048.2080
复制
发表时间：
2021-05-03
影响因子：
4.1
通讯作者：
Yu J
中科院分区：
文献类型：
--
作者：
Brea LT;Wang X;Yu J
背景：虽然局限性前列腺癌 (PCa) 可以通过手术和放疗缓解，但转移性前列腺癌的治疗仍然是一个挑战。雄激素剥夺疗法和雄激素受体（AR）通路抑制剂是晚期前列腺癌的主要治疗方法。然而，耐药性的产生往往会导致去势抵抗性前列腺癌（CRPC）。 Forkhead Box A1 (FOXA1) 是一种先驱转录因子，在调节 AR 活性和促进上皮分化方面发挥着关键作用。研究表明 FOXA1 在 CRPC 肿瘤中经常下调。据报道，FOXA1 缺失会诱导异常的 AR 信号传导、上皮-间质转化和 PCa 去分化。然而，FOXA1在调节PCa免疫反应中的作用这一最近备受关注的领域尚未见报道。由于其免疫抑制性质，CRPC 对免疫检查点抑制剂的反应较差。更好地了解调节 PCa 肿瘤免疫的肿瘤内在机制将为设计更好的靶向免疫治疗方法提供信息。方法：我们进行了 RNA-seq、ChIP-seq、qPCR、蛋白质印迹和 ELISA 分析，以评估 FOXA1 如何调节炎症反应基因。我们利用体外巨噬细胞浸润 Transwell 测定，将 M2 样巨噬细胞添加到上室，将 PCa 细胞铺在下室，以检查 PCa 细胞的扰动如何影响巨噬细胞迁移。最后，我们对患者数据集进行生物信息学分析，以确认 FOXA1 抑制 PCa 炎症基因的临床相关性。结果：通过整合 RNA-seq 和 ChIP-seq 数据，我们发现了 FOXA1 在抑制炎症反应途径中的新功能。相应地，患者数据分析显示，FOXA1 低的 PCa 肿瘤中炎症反应基因上调。从机制上讲，我们发现 FOXA1 蛋白结合缺氧诱导因子 1-α (HIF1A) 基因的基因内增强子，直接抑制其表达，从而 FOXA1 缺失诱导 HIF1A 上调。我们进一步表明，单核细胞趋化蛋白-1 (MCP-1/CCL2) 在 FOXA1 耗尽后以 HIF1A 依赖性方式上调。这导致了免疫抑制、促进肿瘤的 M2 样巨噬细胞的浸润。用 HIF1A 抑制剂或 CCL2 中和抗体抑制 HIF1A-CCL2 轴可阻止巨噬细胞浸润。未来需要使用免疫活性小鼠模型进行研究，以确认 FOXA1 对体内巨噬细胞浸润的影响，并评估在 CRPC 中靶向 FOXA1-HIF1A-CCL2 轴的临床前潜力。结论：本研究提出了 FOXA1 缺失在通过 HIF1A-CCL2 轴促进巨噬细胞浸润方面的新作用。此外，我们的研究结果表明，靶向该轴可能是治疗 FOXA1 低 CRPC 肿瘤的一种有前途的方法。
Background: While localized prostate cancer (PCa) can be mitigated by surgery and radiation, metastatic PCa remains a challenge to treat. Androgen deprivation therapies and androgen receptor (AR) pathway inhibitors are mainstay treatments for advanced PCa. Yet, resistance often develops leading to castration-resistant prostate cancer (CRPC). Forkhead Box A1 (FOXA1) is a pioneer transcription factor that plays pivotal roles in regulating AR activity and promoting epithelial differentiation. Studies have shown that FOXA1 is frequently downregulated in CRPC tumors. Congruently, FOXA1 loss is reported to induce aberrant AR signaling, epithelial-mesenchymal transition, and PCa de-differentiation. However, the role of FOXA1 in regulating PCa immune response, an area of much interest recently, has not been reported. CRPC has shown poor response to immune checkpoint inhibitors, due to its immunosuppressive nature. A better understanding of the tumor intrinsic mechanisms regulating PCa tumor immunity will inform the design of better targeted immunotherapeutic approaches. Methods: We performed RNA-seq, ChIP-seq, qPCR, western blot, and ELISA analyses to evaluate how FOXA1 regulates inflammatory response genes. We utilized an in vitro macrophage infiltration transwell assay, in which M2-like macrophages were added to the upper chamber and PCa cells were plated in the lower chamber, to examine how perturbations to PCa cells affect macrophage migration. Finally, we performed bioinformatic analyses of patient datasets to confirm the clinical relevance of FOXA1 repression of inflammatory genes in PCa. Results: Through integration of RNA-seq and ChIP-seq data, we uncovered a novel function of FOXA1 in suppressing inflammatory response pathways. In accordance, patient data analyses revealed that inflammatory response genes were upregulated in FOXA1-low PCa tumors. Mechanistically, we showed that FOXA1 proteins bound an intragenic enhancer of Hypoxia-inducible factor 1-alpha (HIF1A) gene to directly repress its expression, such that FOXA1 loss induced HIF1A upregulation. We further showed that Monocyte Chemoattractant Protein-1 (MCP-1/CCL2) became upregulated upon FOXA1 depletion in a HIF1A-dependent manner. This led to infiltration by immunosuppressive, tumor promoting M2-like macrophages. Inhibiting this HIF1A-CCL2 axis with a HIF1A inhibitor or CCL2 neutralizing antibody blocked macrophage infiltration. Future studies using immunocompetent mouse models are needed to confirm the effect of FOXA1 on macrophage infiltration in vivo and evaluate the preclinical potential of targeting the FOXA1-HIF1A-CCL2 axis in CRPC. Conclusion: This study proposes a novel role for FOXA1 loss in promoting macrophage infiltration via the HIF1A-CCL2 axis. Moreover, our findings suggest that targeting this axis may be a promising approach for the treatment of FOXA1-low CRPC tumors.