49th FEBS Congress, İstanbul, Turkey, 5 - 09 July 2025, vol.1, no.2025, pp.1-2, (Summary Text)
Fucoidan (FUC), produced from brown algae, also has antitumor effects. Tariquidar(TRQ) is used as a pglycoprotein inhibitor to overcome multidrug resistance. In this study, we aimed to develop multifunctional nanocarriers containing fucoidan for the treatment of doxorubicin(DOX)resistant breast cancer and to demonstrate their efficacy in vitro. DOX was loaded inside the liposomes and TRQ was loaded on the hydrophobic part of the liposomes. FUC was coated on the surface of the liposomes by ionic binding. Resistance development in cells was evaluated by RTPCR and Western blot analysis of Pgp and MRP1. The effect of liposomal agents on apoptotic cell death in MDAMB231R cells was determined flow cytometrically. MDAMB231 cells developed resistance to DOX at increasing concentrations based on the IC50 dose. In MDAMB231R cells, application of liposome constructs composed of DOX, FUC and TRQ decreased cell viability in a timedependent manner in all groups. Resistance development in the cells was mediated by an increase in Pgp and MRP1in gene expression (p< 0.005). In liposomal agents applied to MDAMB231R cells, Pgp protein expression level increased in TRQFUC and DOXFUC groups compared to the control. MRP1 protein showed higher expression levels in LIPODOX, TRQDOXFUC and DOXFUC groups compared to the control. As a result of LIPOFUC treatment of MDAMB231R cells, it was determined that there was a 1fold increase in apoptosis and a 7fold increase in necrosis compared to the control. In the LIPODOX group, there was a 50fold increase in necrosis. While there was no significant increase in apoptosis in the DOXFUC group compared to the control, there was a significant 50fold increase in necrosis. Doxorubicin resistance was developed in triple negative breast cancer and a multifunctional nanocarrier was developed and its invitro cytotoxic activity was demonstrated. This study is financially supported by TUBITAK 1001 (Grant No: 121M625