Fucodain loaded on zinc oxide nanoparticles derived from Turbinaria ornata suppresses skin cancer proliferation and migration via modulation of EMT-related miRNAs.

Fucoidan is a sulfated polysaccharide derived from brown seaweeds that exhibits promising anticancer activity; however, its therapeutic application is limited by poor bioavailability and high molecular weight. This study aimed to evaluate whether loading fucoidan extracted from Turbinaria ornata onto zinc oxide nanoparticles (TF-ZnO-NPs) could enhance its anticancer efficacy against human epidermoid carcinoma (A431) cells and to investigate its effects on apoptosis, proliferation, migration, epithelial-mesenchymal transition (EMT)-related genes, and microRNA expression. TF-ZnO-NPs were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), zeta potential analysis, and transmission electron microscopy (TEM). Anticancer activity was assessed using MTT cytotoxicity assay, Annexin V-FITC/PI apoptosis analysis, cell-cycle analysis, colony formation assay, wound-healing migration assay, and quantitative real-time PCR (qRT-PCR) analysis of EMT-related genes and miRNAs. The synthesized TF-ZnO-NPs exhibited particle sizes ranging from 17.29 to 50.47 nm with a mean size of 32.15 nm. TF-ZnO-NPs demonstrated markedly greater cytotoxicity against A431 cells than free fucoidan, reducing the IC50 value from 666.64 μg/mL to 53.59 μg/mL while maintaining relatively low toxicity toward normal human skin fibroblasts (HSF). TF-ZnO-NPs significantly increased apoptotic and necrotic cell populations, induced cell-cycle arrest at both S and G2/M phases, and strongly inhibited colony formation and cell migration. Molecular analyses revealed significant downregulation of EMT-associated genes, including Twist, Slug, SNAI1, Fibronectin, Vimentin, E-Cadherin, N-Cadherin and BCL2. Furthermore, TF-ZnO-NPs suppressed the oncogenic miRNA miR-222-3p and enhanced the expression of the tumor-suppressive miRNA miR-203a. These findings demonstrate that nanoformulation of fucoidan with ZnO nanoparticles substantially enhances its anticancer activity and its ability to modulate EMT-related molecular pathways and miRNA expression. TF-ZnO-NPs represent a promising nanotherapeutic strategy for the treatment of skin cancer and warrant further investigation in in vivo models.