Table2_miR-145-5p Inhibits Neuroendocrine Differentiation and Tumor Growth by Regulating the SOX11/MYCN Axis in Prostate cancer.XLSX

Recent studies have shown that the downregulation of miR-145-5p in prostate cancer (PCa) is significantly associated with poor differentiation and prognosis. We aimed to investigate the biological role of miR-145-5p in the neuroendocrine differentiation (NED) of PCa. In this study, TheCancer Genome Atlas was used to identify the association of miR-145-5p with PCa. The functions of miR-145-5p were evaluated using the Cell Counting Kit-8 (CCK-8) assay and cell cycle analysis. We validated changes in cell cycle control by testing the expression of cyclin-related genes by western blot. The luciferase reporter assay was performed to test miR-145-5p-targeting genes and direct transcriptional targets of SOX11. The expression of miR-145-5p was found to be significantly downregulated in castration-resistant PCa, and this was correlated with higher Gleason score and prostate-specific antigen. We confirmed these results using PC3 and LNCaP cell lines depicted a gradual decline of miR-145-5p while the cells were cultured under androgen depletion conditions. Moreover, the knockdown of miR-145-5p significantly promoted NED and proliferation of LNCaP cells, whereas overexpression of miR-145-5p significantly inhibited NED and proliferation of LNCaP cells. Mechanistically, we found that SOX11 was a direct target of miR-145-5p, which regulates MYCN might mediate induction of NED and proliferation of LNCaP cells. Furthermore, knockdown of miR-145-5p promoted tumor growth in vivo. Our findings suggest that miR-145-5p can inhibit NED and tumor growth by targeting SOX11, which regulates the expression of MYCN, and that this could be a novel therapeutic strategy for preventing the progression of PCa.已有研究表明，前列腺癌（prostate cancer, PCa）中微小RNA-145-5p（miR-145-5p）的表达下调与肿瘤低分化及不良预后显著相关。本研究旨在探讨miR-145-5p在前列腺癌神经内分泌分化（neuroendocrine differentiation, NED）中的生物学作用。本研究借助癌症基因组图谱（The Cancer Genome Atlas, TCGA）数据库，分析miR-145-5p与前列腺癌的相关性；采用细胞计数试剂盒-8（Cell Counting Kit-8, CCK-8）实验与细胞周期分析，评估miR-145-5p的生物学功能；通过Western blot实验检测细胞周期蛋白相关基因的表达，验证miR-145-5p对细胞周期调控的影响；采用荧光素酶报告基因实验，验证miR-145-5p的靶基因以及SOX11的直接转录靶标。研究发现，去势抵抗性前列腺癌中miR-145-5p的表达显著下调，且该现象与更高的格里森评分（Gleason score）及前列腺特异性抗原（prostate-specific antigen, PSA）水平密切相关。我们通过PC3与LNCaP细胞系验证了上述结果：在雄激素剥夺培养条件下，细胞内miR-145-5p的表达呈逐渐降低趋势。此外，敲低miR-145-5p可显著促进LNCaP细胞的神经内分泌分化与增殖，而过表达miR-145-5p则显著抑制LNCaP细胞的神经内分泌分化与增殖。从机制层面而言，我们发现SOX11是miR-145-5p的直接靶基因，miR-145-5p通过调控SOX11进而影响MYCN的表达，可能介导LNCaP细胞的神经内分泌分化与增殖过程。进一步的体内实验显示，敲低miR-145-5p可促进体内肿瘤生长。本研究结果表明，miR-145-5p可通过靶向SOX11调控MYCN的表达，从而抑制前列腺癌的神经内分泌分化与肿瘤生长，这有望成为阻断前列腺癌进展的新型治疗策略。