Abstract 350P
Background
Glioma grade IV (glioblastoma, GBM) is an aggressive central nervous system tumor, which demonstrates high heterogeneity and resistance to treatment. Patient-derived cell cultures (GBM-lines) were shown to be representative models for analyzing the drug sensitivity of tumor cells for a better choice of appropriate treatment. Our aim was to compare molecular profiles of the tumor and the established patient’s cell line to find out if the cell line preserved important biomarkers of the tumor.
Methods
The study included 22 patients with GBM (19 primary and 3 secondary tumors). The status of IDH1/2, BRAF genes and MGMT promoter were analyzed using real-time PCR and Sanger sequencing. The primary cell lines were obtained from GBM surgical specimens and characterized after 5-6 passages of growing. For five patients, matched samples of tumor tissue, periphery blood and GBM lines were analyzed using 415-gene panel targeted sequencing. Somatic and germline mutations and copy number variations were identified.
Results
The IDH1 mutation was found in two secondary GBM. MGMT promoter was methylated in 13 of 22 tumors. The neuronal origin of cell lines was confirmed by immunofluorescent staining for nestin and β3-tubulin, and proliferation rate was measured. Somatic mutations in PTEN, TP53, RB1, mTOR, PIK3CG, GNAS genes were found in 4/5 tumor samples analyzed by NGS. The CNV changes were detected in chromosomes 10, 13, 15, 17 and 22. One cell line derived from secondary GBM was characterized by a high proliferative rate and had a very similar molecular profile to the initial tumor with additional loss of heterozygosity for mutations in PTEN and TP53 genes. Two cell lines with a slow rate of proliferation had mutation profiles completely different from the initial tumor without specific mutations and CNV changes. Two other lines had the partial coincidence of mutations compared with matched tumors.
Conclusions
Molecular profiling of patient-derived cell lines revealed initial tumor heterogeneity, providing hints for further translational research to better understand the effects of genetic alterations on treatment and prognosis. Thus, the genetic testing of patient-derived cell cultures may be important before using them as a model of glioblastoma tumor cells.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.