Figure 1.

Natural products destroy the shield of CSCs. Radio- and chemotherapy target differentiated cancer cells, which represent most cells within the tumor mass, sparing the CSC subpopulation, characterized by the high expression of ABC transporters, anti-apoptotic molecules, and detoxification enzymes and the aberrant activation of stemness pathways and DNA repair machinery (left part). Natural products derived from different sources (marine, food, and botanical compounds) are able to reduce CSC features and increase their sensitivity to radio- and chemotherapy (right part). DCs, differentiated cells; CSC, cancer stem cell; ABC, ATP-binding cassette.