| 摘要: | 神經內分泌前列腺癌 (NEPC) 是前列腺癌的一種高度侵襲性亞型，可以由原發性於原位癌或通常出現於去勢抵抗性前列腺癌 (CRPC) 激素治療後。識別這種轉分化過程的新分子驅動因素對於改善診斷和治療至關重要。在本研究中，我們研究了兩個候選基因, RNA 剪接調控蛋白, PTBP1,（Polypyrimidine Tract Binding Protein 1）和染色體重塑調控蛋白, BAZ1B,（Bromodomain Adjacent to Zinc Finger Domain 1B）,在前列腺癌神經內分泌表型的進展和維持中的作用，對這兩個基因的興趣源自於它們與眾所周知的神經內分泌分化調控蛋白 PARP11 有關係。在前列腺癌臨床基因數據庫裡 PTB1P與PARP1基因表現密切相關。而BAZ1B 是一種新發現的 PARP1 交互作用蛋白。在此，我們分析了一組前列腺癌細胞株，並揭示了 NEPC 細胞中的 PTBP1 和 BAZ1B 表達相對於其他前列腺癌細胞系（包括激素敏感性前列腺癌或具有活性AR 信號傳導的 CRPC）高度升高。我們透過慢病毒過度表現、shRNA 介導的敲低和 CRISPR/Cas9 敲除克隆產生功能穩定細胞株，以評估 PTBP1 和 BAZ1B 在前列腺癌中的作用。腺癌細胞中的 PTBP1 過度表現增強了 NE 標記的表達和致癌行為，而 NEPC 細胞中的敲低和敲除則抑制了CD56和SYP（兩種經典的 NE 標記）。由於 CDC7 抑制會抑制 NE 轉分化，我們評估了 PTBP1 在 CDC7 介導的 NEPC 中的潛在作用。有趣的是，NEPC細胞對 CDC7 激酶抑制劑 (XL413) 更敏感，但是NEPC細胞中PTBP1的敲除克隆導致對 XL413 的抗性表型。根據我們的初步結果，另一個候選基因 BAZ1B 敲除抑制了幾個 NE 標記，例如 CD56、SYP、SOX2 和 EZH2。簡而言之，我們的研究結果表明 PTBP1 和 BAZ1B 可能分別透過轉錄後（RNA 剪接）和表觀遺傳（染色體重塑）機制來介導神經內分泌分化和腫瘤侵襲性。這項研究提供了 NEPC 進展的機制見解，並提出 PTBP1 和 BAZ1B 作為 NEPC 管理的潛在生物標記和治療標靶。;Neuroendocrine prostate cancer (NEPC) represents a highly aggressive subtype of prostate cancer that emerges from de novo or often after hormone therapy for castration-resistant prostate cancer (CRPC). Identifying novel molecular drivers of this transdifferentiation process is critical for improving diagnosis and treatment. In this study, we investigated the roles of two candidate genes, PTBP1 (Polypyrimidine Tract Binding Protein 1), a RNA splicing regulator, and BAZ1B (Bromodomain Adjacent to Zinc Finger Domain 1B), a chromatin remodeler, in the progression and maintenance of the neuroendocrine phenotype in prostate cancer, because of their relationship with PARP1, a well-known neuroendocrine differentiation regulator. mRNA level of PTBP1 is tightly associated with PARP1 gene expression from clinical prostate cancer dataset. BAZ1B is a novel PARP1 interacting protein.
Herein, we analyzed a panel of prostate cancer cell lines and revealed that PTBP1 and BAZ1B expression in NEPC cells are highly elevated relative to other prostate cancer cell lines including hormone-sensitive prostate cancer or CRPC with constitutive AR signaling. Functional stable lines were generated via lentiviral overexpression, shRNA-mediated knockdown, and CRISPR/Cas9 knockout clones to evaluate the role of PTBP1 and BAZ1B in prostate cancer. PTBP1 overexpression in adenocarcinoma cells enhanced NE marker expression and tumorigenic behaviors, while knockdown and knockout in NEPC cells suppressed CD56 and SYP, 2 classic NE markers. Since CDC7 inhibition suppresses NE trans differentiation, we evaluated the potential role of PTBP1 in CDC7-mediated NEPC. Interestingly, NEPC cells are more sensitive to CDC7 kinase inhibitor (XL413), but knockout clones of PTBP1 in NEPC cell result in resistant phenotype to XL413. Knockout of another candidate gene, BAZ1B, suppressed several NE markers such as CD56, SYP, SOX2, and EZH2 according to our preliminary results. In brief, our findings suggest that PTBP1 and BAZ1B may mediate neuroendocrine differentiation and tumor aggressiveness through post-transcriptional (RNA splicing) and epigenetic (chromatin remodeling) mechanisms respectively. This study provides mechanistic insight into NEPC progression and proposes PTBP1 and BAZ1B as potential biomarkers and therapeutic targets for NEPC management. |
