The present invention provides a method of treating an Hsp70 dependent cancer, including: providing at least one Hsp70 dependent cancer cell contacting the at least one cell with a sub-effective concentration of a dihydropyrimidinone compound and contacting the at least one cell with a sub-effective concentration of a proteasome inhibitor, wherein the sub-effective concentration of the dihydropyrimidinone compound and the sub-effective concentration of the proteasome inhibitor have a synergistic effect upon the at least one cell.
