Previous studies in our lab suggest that nitrogen permease regulator 2-like (NPRL2) upregulation in prostate cancer is associated with malignant behavior and poor prognosis. However, the underlying mechanisms of NPRL2 dysregulation remain poorly understood. This study aimed to explore the transcription factors (TFs) contributing to NPRL2 dysregulation in prostate cancer. Potential TFs were identified using prostate tissue/cell-specific chromatin immunoprecipitation (ChIP)-seq data collected in the Cistrome Data Browser and Signaling Pathways Project. Dual-luciferase assay and ChIP-qPCR assay were conducted to assess the binding and activating effect of TFs on the gene promoter. Cell Counting Kit-8 and colony formation assays were performed to assess cell proliferation. Results showed that E2F1 is a TF that bound to the NPRL2 promoter and activated its transcription. NPRL2 inhibition significantly alleviated E2F1 enhanced cell proliferation. Kaplan–Meier survival analysis indicated that E2F1 upregulation was associated with unfavorable progression-free survival and disease-specific survival. FOXO1 interacted and E2F1 in both PC3 and LNCaP cells and weakened the binding of E2F1 to the NPRL2 promoter. Functionally, FOXO1 overexpression significantly slowed the proliferation of PC3 and LNCaP cells and also decreased E2F1 enhanced cell proliferation. In summary, this study revealed a novel FOXO1/E2F1-NPRL2 regulatory axis in prostate cancer. E2F1 binds to the NPRL2 promoter and activates its transcription, while FOXO1 interacts with E2F1 and weakens its transcriptional activating effects. These findings help expand our understanding of the prostate cancer etiology and suggest that the FOXO1/E2F1-NPRL2 signaling axis might be a potential target.

中文翻译：

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FOXO1通过抑制E2F1激活的NPRL2表达抑制前列腺癌细胞增殖

我们实验室以前的研究表明，前列腺癌中的氮通透酶调节剂 2 样 (NPRL2) 上调与恶性行为和预后不良有关。然而，NPRL2失调的潜在机制仍然知之甚少。本研究旨在探索促成NPRL2的转录因子 (TFs)前列腺癌的失调。使用在 Cistrome 数据浏览器和信号通路项目中收集的前列腺组织/细胞特异性染色质免疫沉淀 (ChIP)-seq 数据鉴定了潜在的 TF。进行双荧光素酶测定和 ChIP-qPCR 测定以评估 TF 对基因启动子的结合和激活作用。进行细胞计数 Kit-8 和集落形成测定以评估细胞增殖。结果表明，E2F1 是一个与NPRL2启动子结合并激活其转录的 TF。NPRL2抑制显着减轻了E2F1增强的细胞增殖。Kaplan–Meier 生存分析表明，E2F1 上调与不利的无进展生存期和疾病特异性生存期相关。FOXO1 在 PC3 和 LNCaP 细胞中与 E2F1 相互作用并削弱 E2F1 与NPRL2的结合发起人。在功能上，FOXO1 过表达显着减缓了 PC3 和 LNCaP 细胞的增殖，并且还降低了 E2F1 增强的细胞增殖。总之，这项研究揭示了前列腺癌中一种新的 FOXO1/E2F1-NPRL2 调节轴。E2F1 与 NPRL2 启动子结合并激活其转录，而 FOXO1 与 E2F1 相互作用并削弱其转录激活作用。这些发现有助于扩大我们对前列腺癌病因的理解，并表明 FOXO1/E2F1-NPRL2 信号轴可能是一个潜在的靶点。