Conditioned Medium of Glioblastoma Cells Decreases the Viability of Each Other by Modulating Apoptosis- and Proliferation-Related Gene Expression

Background: Grade IV neoplasm of the central nervous system, GBM, is associated with poor prognosis and short overall survival. Objectives: This study aimed to investigate the effects of conditioned mediums of GBM cell lines on each other. Methods: Conditioned mediums of GBM cell lines were harvested at the 6th, 12th, 24th, and 48th h time points. The cellular and molecular effects of conditioned mediums were evaluated using gold standard techniques such as MTT assay, colony formation assay, wound healing assay, EdU labeling-based flow cytometry, and qRT-PCR. Results: Our study demonstrated that conditioned medium harvested from U87 or LN229 cells at the 48th h time point exhibited an anti-growth activity on each other by altering the gene expression pattern. Furthermore, the conditioned medium of LN229 decreased the migration capacity of U87 cells, and the conditioned medium of U87 cells significantly suppressed the LN229 proliferation. Conclusions: Growth-limiting activity achieved by conditioned mediums collected at the 48th h time point positioned them as promising candidates to further investigate their content. It was argued that this initial work provided new insights to expand our current understanding of the roles of GBM cells’ secretome.