Treatment of 13a (200 nM) or 13a (200 nM) in combination with bortezomib (5 nM) for 3 h, 6 h and 9 h, respectively. p53 begins to degrade in treatment of 13a at 6 h, and the degradation can be rescued by bortezomib. 7B. Treatment of 13a 50 nM, 100 nM or in combination with bortezomib (5 nM). Bortezomib can promote 13a-triggered apoptosis. 7C. Combination Index (CI) for 13a and Bortezomib after treatment 0f 24 h. Data was analyzed using CompuSyn Software. CI < 1, = 1, and > 1 indicate synergism, additive effect, and antagonism, respectively.