Abstract：
In this investigation, we extensively studied the mechanism of antitumor activity of bovine pancreatic RNase A. Using confocal microscopy, we show that after RNase A penetration into HeLa and B16 cells, a part of the enzyme remains unbound with the ribonuclease inhibitor (RI), resulting in the decrease in cytosolic RNAs in both types of cells and rRNAs in the nucleoli of HeLa cells. Molecular docking indicates the ability of RNase A to form a complex with Ku70/Ku80 heterodimer, and microscopy data confirm its localization mostly inside the nucleus, which may underlie the mechanism of RNase A penetration into cells and its intracellular traffic. RNase A reduced migration and invasion of tumor cells in vitro. In vivo, in the metastatic model of melanoma, RNase A suppressed metastases in the lungs and changed the expression of EMT markers in the tissue adjacent to metastatic foci; this increased Cdh1 and decreased Tjp1, Fn and Vim, disrupting the favorable tumor microenvironment. A similar pattern was observed for all genes except for Fn in metastatic foci, indicating a decrease in the invasive potential of tumor cells. Bioinformatic analysis of RNase-A-susceptible miRNAs and their regulatory networks showed that the main processes modulated by RNase A in the tumor microenvironment are the regulation of cell adhesion and junction, cell cycle regulation and pathways associated with EMT and tumor progression.
摘要：
在这次调查中,我们广泛研究了牛胰腺RNA酶A的抗肿瘤活性机制。使用共聚焦显微镜，我们发现RNaseA穿透HeLa和B16细胞后，部分酶仍未与核糖核酸酶抑制剂（RI）结合，导致两种类型细胞中的胞浆RNA和HeLa细胞核仁中的rRNA减少。分子对接表明RNaseA与Ku70/Ku80异源二聚体形成复合物的能力，显微镜数据证实了它主要在细胞核内的定位，这可能是RNaseA渗透到细胞及其细胞内运输的机制的基础。RNaseA在体外降低肿瘤细胞的迁移和侵袭。在体内,在黑色素瘤的转移模型中，RNaseA抑制了肺中的转移，并改变了转移灶附近组织中EMT标志物的表达；这增加了Cdh1，降低了Tjp1，Fn和Vim，破坏有利的肿瘤微环境。除转移灶中的Fn外，所有基因均观察到相似的模式，表明肿瘤细胞的侵袭潜能降低。对RNase-A敏感的miRNAs及其调控网络的生物信息学分析表明,RNaseA在肿瘤微环境中调控的主要过程是细胞粘附和连接的调控,与EMT和肿瘤进展相关的细胞周期调控和通路。
