P13.23 Study of migration characteristics of human glioma cells in vitro

BACKGROUND

Gliomas are still one of the most aggressive human cancers, and even despite modern therapeutic approaches, the prognosis for patients with this disease is not favorable. It is known that glioma cells are capable of local invasiveness, when glioma cells migrate into healthy brain tissue. A lack of any definite markers, characterizing migrating glioma cells and allowing them to be distinguished from healthy brain cells, requires a thorough investigation. In case it would be possible to characterize invasive glioma cells, then a development of targeted therapy could be feasible.

MATERIAL AND METHODS

Cell cultures of human gliomas Gr II, III and IV were developed with 5 cultures for each Grade. MTT, RT-PCR, Western and Nosern blot, transcriptome analysis were applied.

RESULTS

Three cultures of human gliomas had a high degree of migration, within the range of 6% - 14%. These cultures were developed from gliomas of Grade III and Grade IV, and with IDH1- (minus) phenotype. Moreover, cell cultures with IDH1 + (plus) phenotype had a low migration rate within 1%. An intensity of migration correlated with the degree of malignancy, and an average rate decreased with a decrease of the Grade. Moreover, an analysis of the proliferative activity of cell cultures of human gliomas of various degrees of malignancy did not reveal a relationship with a migratory properties of cultures. A number of actively proliferating cultures did not show high migration, while cultures with medium proliferative activity could show a high level of migration. The low level of proliferation of cultures of gliomas of Grade II and I at the beginning of cultivation, in some cases, subsequently increased, but an inherent low migration activity did not change. In actively migrating cultures, a significant decrease in the expression of Sox2 and Nestin is detected. A positive correlation was found between migration abilities of human glioma cell culture cells and the marker Ki67, GFAP, Sox2, and Oct4. The difference was statistically significant by the one-sided Mann-Whitney test.

CONCLUSION

Conclusions: Cell cultures derived from glioma tumor tissue can be used to predict invasive properties of the tumor. High tumor invasiveness is characteristic for Grade III and Grade IV, and with IDH1- (minus) phenotype, and it also correlates with elevated expression of GFAP, Sox2 and Oct4The reported study was funded by RFBR according to the research project № 18-29-01012 and by the Ministry of Science and Higher Education of the Russian Federation, grant number 075-15-2020-809 (13.1902.21.0030).

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

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

P11.64 Specialized neurooncologial biorepository of the N.N. Burdenko National Medical Research Center for Neurosurgery: high-quality tumor bank for personalized medicine

BACKGROUND

Specialized biorepositories in neurooncology serve for storage of tissue samples derived from patients with central nervous system (CNS) tumors. In 2016 the new facility was launched for collection of CNS tumor specimens. The principal aim of the repository is preparation of frozen CNS tumor samples accompanied by associated clinical, pathological, molecular, and follow-up data.

MATERIAL AND METHODS

Each surgical biopsy was divided into several aliquots (usually three), registered, and stored in LN2. Since August 2018 from all aliquots a lesser fragment was separated for paraffin block processing. This histological control was applied for quality assurance of frozen samples. Each specimen record was accompanied with demographic, clinical, perioperative, and histological data. In the follow-up, oncological treatment and response to therapy were added to the databank as well as molecular data. All tumor samples are characterized, passportized, stored, and systemically revised. The following biomarkers were evaluated: Cdk4, Cdk6, FGFR, NANOG, OCT4, SOX2, MELK, Nestin, Notch2, Olig2, GFAP, MAP2, β-III-tubulin, PDGFRA. Dedicated original flexible electronic data storage system was designed for information support of tumor collection. Specimen acquisition, procurement, and storage was encoded using SPREC 2.0 coding system.

RESULTS

Between March 2016 till January 2019 a total of 596 biopsy samples were stored in the repository. All of them were obtained from the patients operated on in N.N. Burdenko National Medical Research Center for Neurosurgery. Among all entities brain gliomas prevailed and comprised 539 biopsy specimens (90,4%). Specimen quality control using histology, immunohistochemistry, fluorescent in situ hybridization, and molecular methods was performed. The frequency of appropriate aliquots is as high as 83,4%. Tumor sample collection included primary and recurrent cases including those, which underwent primary and secondary in N.N. Burdenko National Medical Research Center for Neurosurgery.

CONCLUSION

Specialized neurooncological biorepository is advantageous due to possibility of tumor tissue collection at different stages of the disease. The associated databank contains patients’ data, tumor tissue data, treatment data, response to treatment, and follow-up data. Further development of the facility will provide collection of the larger spectrum of neurooncological entities, creation of tumor cell culture bank, and experimental therapies for the development of personalized neurooncological treatment.