GAPDH and cancer: The capabilityof PAs-HumAfFt to host and deliver siRNA molecules through human transferrinreceptor (TfR1), overexpressed in many cancer cells, was explored.These systems allowed siRNA delivery into HeLa, HepG2, and MCF-7 cancercells with improved silencing effect on glyceraldehyde-3-phosphatedehydrogenase (GAPDH) gene expression with respect to traditionaltransfection methodologies and provided a promising TfR1-targetingsystem for multifunctional siRNA delivery to therapeutic applications.