An interesting therapy combination has been uncovered in preclinical studies. In an ovarian cancer cell line, the proteasome inhibitor bortezomib acted synergistically with indole-3-carbinol, a natural compound found in cruciferous vegetables. Treatment with the combination induced cell-cycle arrest and apoptosis and sensitized the cells to chemotherapy. Importantly, in mouse models, treatment with the combination inhibited tumor growth and reduced tumor weight compared with treatment with either single agent.