Susceptibility of cancer cells to β-lapachone is enhanced by ionizing radiation

The sensitivity of cells to β-lap is dependent on NQO1 activity. IR caused a long-lasting increase in NQO1 activity in cancer cells, thereby sensitizing cells to β-lap and treatment of experimental mouse tumors with IR and β-lap suppressed tumor growth in a synergistic manner. The combination of β-lap and radiotherapy is a potentially effective regimen for the treatment of human cancer.