RNA Aptamers for Theranostics of Glioblastoma of Human Brain

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Alexey M. Kopylov^1,a,*, Lika V. Fab², Olga Antipova¹, Ekaterina A. Savchenko³, Alexander V. Revishchin², Viktoriya V. Parshina², Svetlana V. Pavlova², Igor I. Kireev¹, Andrey V. Golovin^1,4, Dmitry Y. Usachev³, and Galina V. Pavlova^2,3,4

¹Chemistry Department, Lomonosov Moscow State University, 119991 Moscow, Russia

²Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 117485 Moscow, Russia

³Burdenko National Medical Research Center of Neurosurgery, Ministry of Health of the Russian Federation, 125047 Moscow, Russia

⁴Sechenov First Moscow State Medical University, 119991 Moscow, Russia

^* To whom correspondence should be addressed.

Received May 26, 2021; Revised June 15, 2021; Accepted June 15, 2021

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Conventional approaches for studying and molecular typing of tumors include PCR, blotting, omics, immunocytochemistry, and immunohistochemistry. The last two methods are the most used, as they enable detecting both tumor protein markers and their localizations within the cells. In this study, we have investigated a possibility of using RNA aptamers, in particular, 2′-F-pyrimidyl-RNA aptamer ME07 (48 nucleotides long), specific to the receptor of epidermal growth factor (EGFR, ErbB1, Her1), as an alternative to monoclonal antibodies for aptacytochemistry and aptahistochemistry for human glioblastoma multiforme (GBM). A specificity of binding of FAM-ME07 to the receptor on the tumor cells has been demonstrated by flow cytometry; an apparent dissociation constant for the complex of aptamer – EGFR on the cell has been determined; a number of EGFR molecules has been semi-quantitatively estimated for the tumor cell lines having different amount of EGFR: A431 (10⁶ copies per cell), U87 (10⁴ copies per cell), MCF7 (10³ copies per cell), and ROZH, primary GBM cell culture derived from patient (10⁴ copies per cell). According to fluorescence microscopy, FAM-ME07 interacts directly with the receptors on A431 cells, followed by its internalization into the cytoplasm and translocation to the nucleolus; this finding opens a possibility of ME07 application as an escort aptamer for a delivery of therapeutic agents into tumor cells. FAM-ME07 efficiently stains sections of GBM clinical specimens, which enables an identification of EGFR-positive clones within a heterogeneous tumor; and providing a potential for further studying animal models of GBM.

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KEY WORDS: 2′-fluoro-pyrimidyl-RNA-aptamer, EGFR, human glioblastoma, cell cultures, flow cytometry, fluorescence microscopy

DOI: 10.1134/S0006297921080113

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