Butyl and isobutyl ortho-coumaric acid derivatives reduce self-renewal and MGMT expression in GBM cells with stem cell-like characteristics

Ortho-coumaric acid (o-CA) derivatives, specifically butyl, isobutyl, propyl, ethyl, and methyl-o-coumarate, have emerged as potential therapeutic agents for glioblastoma multiforme (GBM). This study investigates their effects on drug resistance, proliferation, migration, maturation, cell cycle regulation, and autophagy in stem-like glioblastoma cells (SLGCs). We evaluated the biological activity of o-CA derivatives using an in vitro GBM cell model by assessing spheroid and colony formation, cell migration, autophagy marker induction, DNA damage repair protein expression, cell cycle alterations, and the expression of stemness and differentiation markers. Treatment with o-CA derivatives, particularly butyl and isobutyl, resulted in a decreased self-renewal capacity of SLGCs, as indicated by reduced spheroid and colony formation compared to temozolomide (TMZ). Additionally, butyl o-CA impaired cell migration. Cell cycle analysis revealed an increased proportion of cells in the G0/G1 phase following treatment with butyl and isobutyl o-CA, accompanied by a reduction in the S and G2/M phases. Furthermore, we observed increased expression of the autophagy marker microtubule-associated protein 1 light-chain 3B (LC3-B) in cells treated with propyl and butyl o-CA. The expression of the drug resistance marker O6-methylguanine DNA methyltransferase (MGMT) was significantly reduced, particularly in cells treated with Butyl o-CA. Moreover, butyl o-CA-treated cells demonstrated lower expression levels of the stemness markers CD133 and Nestin, in conjunction with elevated expression of the differentiation markers GFAP and NeuN. Overall, these findings suggest that o-CA derivatives, especially butyl and Isobutyl o-CA, may effectively modulate stem-like characteristics in an in vitro GBM model.