Concentrated Growth Factor Induces <scp>ER</scp> Stress and Apoptosis by Increasing Ceramide Generation in Selected Tumour Cell Lines

Concentrated growth factor (CGF), a blood-derived autologous biomaterial, is increasingly utilised in regenerative medicine and, recently, in cancer-related surgeries. Rich in cytokines, platelets, nucleated cells and fibrin scaffolds, CGF offers therapeutic promise but requires rigorous safety evaluation in oncology. This study explores the effects of CGF-conditioned medium (CGF-CM) on breast cancer (MCF7, MDA-231) and osteosarcoma (SaOS-2, MG-63) cell lines. Our findings reveal that CGF-CM selectively induces cytotoxic effects in MCF7 and SaOS-2 cells, while no cytotoxicity was observed in MDA-231 and MG-63 cells. Early apoptosis in MCF7 and SaOS-2 cells was accompanied by mitochondrial dysfunction, evidenced by an increased BAX/BCL-2 ratio and cytochrome c release. CGF-CM treatment also elevated ceramide and triglyceride levels, linking lipid metabolic changes to cancer cell death. Endoplasmic reticulum (ER) stress markers, ATF6 and XBP1, were significantly upregulated in MCF7 and SaOS-2 cells, highlighting the role of ER stress in CGF-CM-induced cytotoxicity. Furthermore, CGF-CM inhibited autophagic flux, as demonstrated by altered LC3 and p62 protein levels, disrupting cellular homeostasis and contributing to apoptosis. These findings highlight the selective cytotoxic effects of CGF-CM on specific cancer cell lines. The intricate interplay between mitochondrial dysfunction, ER stress, autophagy inhibition and lipid metabolism highlights its complex mechanisms of action.