Plyasova Anna A, Pokrovskaya Marina V, Lisitsyna Olga M, Pokrovsky Vadim S, Alexandrova Svetlana S, Hilal Abdullah, Sokolov Nikolay N, Zhdanov Dmitry D
Institute of Biomedical Chemistry, Pogodinskaya st. 10/8, 119121 Moscow, Russia.
International Biotechnology Center "Generium" LLC, Vladimirskaya st. 14, 601125 Volginsky, Russia.
Pharmaceuticals (Basel). 2020 Sep 30;13(10):286. doi: 10.3390/ph13100286.
The anticancer effect of L-asparaginases (L-ASNases) is attributable to their ability to hydrolyze L-asparagine in the bloodstream and cancer cell microenvironment. (RrA) has dual mechanism of action and plays a role in the suppression of telomerase activity. The aim of this work was to investigate the possible mechanism of RrA penetration into human cancer cells. Labeling of widely used L-ASNases by fluorescein isothiocyanate followed by flow cytometry and fluorescent microscopy demonstrated that only RrA can interact with cell membranes. The screening of inhibitors of receptor-mediated endocytosis demonstrated the involvement of clathrin receptors in RrA penetration into cells. Confocal microscopy confirmed the cytoplasmic and nuclear localization of RrA in human breast cancer SKBR3 cells. Two predicted nuclear localization motifs allow RrA to penetrate into the cell nucleus and inhibit telomerase. Chromatin relaxation promoted by different agents can increase the ability of RrA to suppress the expression of telomerase main catalytic subunit. Our study demonstrated for the first time the ability of RrA to penetrate into human cancer cells and the involvement of clathrin receptors in this process.
L-天冬酰胺酶（L-ASNases）的抗癌作用归因于其水解血液和癌细胞微环境中L-天冬酰胺的能力。（RrA）具有双重作用机制，并在抑制端粒酶活性中发挥作用。这项工作的目的是研究RrA渗透入人类癌细胞的可能机制。用异硫氰酸荧光素标记广泛使用的L-ASNases，然后进行流式细胞术和荧光显微镜检查，结果表明只有RrA能与细胞膜相互作用。对受体介导的内吞作用抑制剂的筛选表明，网格蛋白受体参与了RrA渗透入细胞的过程。共聚焦显微镜证实了RrA在人乳腺癌SKBR3细胞中的细胞质和细胞核定位。两个预测的核定位基序使RrA能够渗透入细胞核并抑制端粒酶。不同试剂促进的染色质松弛可增强RrA抑制端粒酶主要催化亚基表达的能力。我们的研究首次证明了RrA渗透入人类癌细胞的能力以及网格蛋白受体在此过程中的参与。
