Proteasome inhibition in cancer is associated with enhanced tumor targeting by the adeno-associated virus/phage

► Proteasome in cancer is a barrier to tumor targeting by RGD4C/AAVP. ► Proteasome inhibiting drugs enhance targeted gene transfer by RGD4C/AAVP. ► Proteasome inhibition increases targeted cancer gene therapy by RGD4C/AAVP. ► RGD4C/AAVP persistence in cancer is improved by proteasome inhibition