Противоопухолевый эффект камптотецина в отношении клеток глиобластомы человека посредством подавления экспрессии BRIP1

Antitumor effect of camptothecin against human glioblastoma cells through suppression of BRIP1 expression

Introduction. Glioblastoma is the most aggressive and common malignant brain tumor characterized by high heterogeneity, infiltration capacity and frequent relapses. BRCA1 interacting protein C-terminal helicase 1 (BRIP1) is involved in the DNA repair system and, according to a number of studies, may play a significant role in oncogenesis. Camptothecin, a topoisomerase I inhibitor, has a cytotoxic effect on many tumor cells, but its influence on BRIP1 expression in glioblastoma has not been adequately studied to date. Aim – to determine the role of the BRIP1 gene in glioblastoma progression and to evaluate the antitumor effect of camptothecin associated with BRIP1 inhibition in vitro. Materials and methods. We identified differentially expressed genes in 2 datasets (GSE54004 and GSE43378) containing primary low-and high-grade glioma tissue samples from the Gene Expression Omnibus database. We carried out functional analysis using the Gene Ontology database and Kyoto Encyclopedia of Genes and Genome, as well as constructed a protein-protein interaction network and identified key genes using the cytoHubba plugin in Cytoscape. CMap analysis was utilized to identify compounds capable of suppressing the overexpressed genes in glioblastoma, including BRIP1. Glioblastoma cell lines (U251, U87, and LN229) and human brain astrocytes were used in the experimental part of our study. BRIP1 protein expression level was assessed by Western blot analysis. The antitumor activity of camptothecin was investigated using an MTT assay and flow cytometry. The study was approved by the Independent Ethics Committee and the Scientific Council of the N.I. Pirogov Russian National Research Medical University of Ministry of Healthcare of the Russian Federation. Results. Among the 200 differentially expressed genes found to be significantly overexpressed in high-grade gliomas, BRIP1 showed high interaction scores in the protein-protein interaction network and was associated with DNA repair pathways, homologous recombination, and cell cycle (GSEA results). CMap search identified camptothecin as one of the promising small molecule compounds for BRIP1 suppression (enrichment –0.949 and p=0.00026). The expression level of BRIP1 protein was increased in U251, U87, and LN229 cell lines compared with human brain astricytes, which supports our data obtained by Western blot analysis. The introduction of camptothecin into U251 culture in a dose-dependent manner reduced the viability and proliferation of tumor cells, inhibited their migration, and induced apoptosis which was accompanied by a dose-dependent decrease in the level of BRIP1 protein expression. Conclusion. This study highlights a key role of BRIP1 in the development of glioblastoma and demonstrates that camptothecin can completely or partially inhibit glioblastoma development and progression by suppressing BRIP1 activity. Our findings suggest that BRIP1 may be considered as a potential therapeutic target and confirm the need for further development of camptothecin and its analogs for targeted therapy of glioblastoma. © 2025 by «D. Rogachev NMRCPHOI».