Combined treatment of CAPE with chemotherapy drugs shows synergistic and antagonistic inhibition on proliferation of PC-3 cells.

<p>Proliferation of PC-3 cells treated with increasing dosage (0, 5, 10, 20 µM) of CAPE in combination with increasing concentration of etoposide (A), paclitaxol (B), vinblastine (C), mitoxantrone (D), and estramustine (E) for 72 h was determined by 96-well proliferation assay. The right part of the figure show the ratio of expected cell number/observed cell number. For example, treatment of 5 µM of CAPE or 1 nM vinblastine decreases cell number of PC-3 to 80.9% and 88.7%, respectively, compared to the control (no treatment). The expected cell number of treatment combining 5 µM of CAPE and 1 nM vinblastine is 0.809*0.887 = 71.8%. The observed cell number is 48.8% compared to the control. So the ratio is 0.718/0.488 = 1.5. Ratio larger than one represents synergy of growth inhibition, while ratio smaller than one represents antagonistic effect.