P13.19 Bi-modular G-quadruplex DNA-crypto-aptamers diminish viability of glioma primary cell cultures of patients

Abstract

Abstract BACKGROUND G-quadruplex oligonucleotides (GQs) exhibit specific anti-survival activity in human cancer cell lines; they can selectively inhibit the viability/proliferation. The most studied, AS1411, had been in clinical trials. This anti-proliferative ability of GQs could be translated into glioma, which currently has poor prognosis and low-efficiency therapeutic treatments for glioblastoma multiform (GBM). Set of GQs have been designed, synthesized, and tested: they have different amount of Q-quartets, they have dimers of different GQ modules: either covalent dimers or non-covalent ones; all of them could be coined as ‘twins’. MATERIAL AND METHODS Folding of synthetic DNA oligonucleotides into GQs and thermal stability have been studied by circular dichroism, melting with unfolding-folding regimes, oligomerization was followed by original SE-HPLC. Conventional human cell lines U87 and fibroblasts from human embryo (HEF) were provided from the collection of the Centre of Neurosurgery (Moscow, Russia). GBM primary cell cultures N1, G11, Sus/fP2, G22, G23, and G01 were developed in Burdenko National Medical Research Centre of Neurosurgery (NMRCN) from the surgery samples of patients (PCC_SSP). All samples had WT IDH1. This study was approved by the Ethics Committee of Burdenko NMRCN, Russian Academy of Medical Sciences (№_12/2020, 15.12.2020). All subjects gave written informed consent in accordance with the guidelines of Declaration of Helsinki. Cell viability was tested by conventional MTT-test. RESULTS Novel bi-modular GQ, bi-(AID-1-T), twin of three-quartet AID-1-T, was designed by covalent conjugation of two AID-1-Ts via three thymidine link, TTT; and linking did not interfere with its GQ structure. Comparison of bi-(AID-1-T) with mono-modular AID-1-T, mono-modular two-quartet HD1, bi-modular bi-HD1, and two-quartet AS1411, was made. Among five GQs, bi-(AID-1-T) had the highest anti-survival activity for U87, while not affecting the control, HEF. GQs, for the first time, were tested on several PCC_SSP. Sensitivity of PCC_SSP toward GQs varied, with apparent IC50 of less than 1 μM for bi-(AID-1-T) toward the most sensitive G11 (glioma, Grade III). CONCLUSION GQs as anti-proliferative crypto-aptamers with moderate activity due to restricted functioning of apparent GQ-binding proteins could be applied toward real glioma PCC_SSP. Variety of effects reflects glioma inter-tumor heterogeneity.Research was funded by Ministry of Education and Science of Russia, grant number № 075-15-2020-809 (13.1902.21.0030) and by Russian Foundation for Basic Research, grants number №18-29-01047