Targeting CPT1B as a potential therapeutic strategy in castration-resistant and enzalutamide-resistant prostate cancer
Targeting CPT1B as a potential therapeutic strategy in castration-resistant and enzalutamide-resistant prostate cancer
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靶向 CPT1B 作为去势抵抗性和恩杂鲁胺抵抗性前列腺癌的潜在治疗策略
DOI：
10.1002/pros.24027
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发表时间：
2020-07-10
期刊：
影响因子：
2.8
通讯作者：
Ye, Dingwei
中科院分区：
文献类型：
--
作者：
Abudurexiti, Mierxiati;Zhu, Wenkai;Ye, Dingwei
前列腺癌的特点是脂质代谢异常，包括脂肪酸氧化升高。肉毒碱棕榈酰基转移酶1B （CPT1B）催化脂肪酸氧化的限速步骤。本研究旨在确定CPT1B是否在前列腺癌进展中起关键作用，并确定其调控机制。方法将来自Cancer Genome Atlas和Gene Expression Omnibus数据库的cpt1表达数据与患者生存数据进行比较。用60例前列腺癌标本构建组织芯片，进行CPT1B免疫组化染色。建立了稳定敲除cpt1表达的抗去势前列腺癌（CRPC）细胞系22RV1和C4-2；分别采用细胞计数试剂盒-8 （CCK-8）、菌落形成实验、流式细胞术和Transwell实验检测细胞增殖、细胞周期分布和侵袭情况。为了研究雄激素受体（AR）抑制对CPT1B表达的影响，我们搜索了JASPAR CORE，以确定CPT1B中AR的结合位点。双荧光素酶和ChIP实验分别证实CPT1B活性和AR结合。对前列腺癌中差异表达基因（DEGs）进行基因集富集分析（GSEA）。生成enzalutamide耐药C4-2细胞，通过CCK-8试验探讨enzalutamide耐药机制及CPT1B对C4-2的下游信号通路变化。结果与正常前列腺组织相比，cpt1在人前列腺癌中表达上调，并与较差的无病生存期和总生存期相关。CPTB1的沉默导致细胞增殖下调，s期分布减少，侵袭能力降低，而在过表达CPTB1的CRPC细胞中观察到相反的结果。前列腺癌中的DEGS与g蛋白偶联受体信号、分子换能器活性和钙离子结合相关。双荧光素酶和ChIP实验证实，AR可能通过特定的结合位点调节ecpt1的表达和活性。CCK-8实验表明，CPT1B在C4-2细胞中的过表达并未显著增加对恩杂鲁胺的抗性。然而，CPT1B在C4-2R细胞中的过表达显著增加了对恩杂鲁胺的耐药性。上调CPT1B表达可增加AKT的表达和磷酸化。结论CPT1B在前列腺癌中表达上调，与预后不良相关，具有作为生物标志物的潜力。AR抑制CPT1B的转录。在CRPC细胞系中，单独过表达CPT1B不能促进对恩杂鲁胺的耐药，但在耐药细胞系C4-2R中，过表达CPT1B可促进C4-2R对恩杂鲁胺的耐药。
Background Prostate cancer is characterized by aberrant lipid metabolism, including elevated fatty acid oxidation. Carnitine palmitoyltransferase 1B (CPT1B) catalyzes the rate-limiting step of fatty acid oxidation. This study aimed to determine if CPT1B has a critical role in prostate cancer progression and to identify its regulatory mechanism. Methods CPT1Bexpression data from The Cancer Genome Atlas and Gene Expression Omnibus databases was compared with patient survival data. A tissue microarray was constructed with 60 samples of prostate cancer and immunohistochemically stained for CPT1B. Castration-resistant prostate cancer (CRPC) cell lines 22RV1 and C4-2 in whichCPT1Bexpression had been stably knocked down were established; and cell proliferation, cell cycle distribution, and invasion were investigated by Cell Counting Kit-8 (CCK-8) and colony formation assays, flow cytometry, and Transwell assays, respectively. To examine the impact of androgen receptor (AR) inhibition onCPT1Bexpression, JASPAR CORE was searched to identify AR-binding sites in CPT1B. Dual luciferase and ChIP assays were performed to confirm CPT1B activity and AR binding, respectively. Differentially expressed genes (DEGs) in prostate cancer underwent gene set enrichment analysis (GSEA). Enzalutamide-resistant C4-2 cells were generated and the mechanism of enzalutamide resistance and downstream signaling pathway changes of CPT1B to C4-2 was explored through CCK-8 test. Results CPT1Bexpression was upregulated in human prostate cancer compared with normal prostate tissue and was associated with poor disease-free survival and overall survival. Silencing ofCPT1Bresulted in downregulated cell proliferation, reduced S-phase distribution, and lower invasive ability, whereas the opposite was observed in CRPC cells overexpressing CPTB1. DEGS in prostate cancer were correlated with G-protein-coupled receptor signaling, molecular transducer activity, and calcium ion binding. AR may regulateCPT1Bexpression and activity via specific binding sites, as confirmed by dual luciferase and ChIP assays. The CCK-8 experiment demonstrated that CPT1B overexpression in C4-2 cells did not significantly increase the ability of enzalutamide resistance. However, overexpression of CPT1B in C4-2R cells significantly increased the enzalutamide resistance. Upregulation of CPT1B expression increased AKT expression and phosphorylation. Conclusions CPT1B is upregulated in prostate cancer and is correlated with poor prognosis, indicating its potential as a biomarker. AR inhibits the transcription of CPT1B. In the CRPC cell line, overexpression of CPT1B alone cannot promote enzalutamide resistance, but in the drug-resistant line C4-2R, overexpression of CPT1B can promote the resistance of C4-2R to enzalutamide.