Abstract

Background

Marine ecosystems are an underexplored source of structurally diverse bioactive compounds with therapeutic potential. Among these, glycosaminoglycans (GAGs) have gained attention for their anticoagulant, antioxidant, anti-inflammatory, and antitumor properties. Glioblastoma, the most aggressive malignant primary brain tumor in adults, remains largely incurable due to its high invasiveness, therapeutic resistance, and the protective blood–brain barrier. Therefore, the ongoing need to identify new treatment candidates persists.

Aims

This study aimed to investigate the potential anticancer effects of Dicentrarchus labrax (European seabass) scale extract (DLSE) on human glioblastoma U-87MG cells.

Methods

GAG-containing extracts were prepared from fish scales, and their chemical structures were characterized using Fourier-transform infrared (FTIR) spectroscopy. Cell viability was determined by the MTT assay, migration by scratch wound-healing assay, apoptosis by Hoechst/PI staining, and molecular changes by immunoblotting.

Results

FTIR analysis confirmed the key functional groups consistent with a GAG-like polysaccharide profile. DLSE reduced cell viability in a dose- and time-dependent manner, with an IC50 value of 993 μg/mL at 72 hours. Treatments with 600 and 1000 μg/mL DLSE for 72 hours inhibited cell migration, induced apoptosis, increased the Bax/Bcl-2 ratio, and elevated levels of cleaved caspase-3 and PARP1. DLSE also activated p53/p21-mediated cell-cycle regulatory pathways, and induced ER stress through dose-dependent increases in Grp78, PERK, IRE1α, and cleaved ATF6 levels.

Conclusion

Our findings indicate that GAG-containing DLSE stimulates multiple antitumor pathways in glioblastoma cells. Although further in vivo research and compound fractionation are necessary, marine-derived GAG-rich extracts could be promising adjuncts for glioblastoma therapy.