9.2.27PE and ABT-737 in Melanoma Figure 5. Calcium release caused by 9.2.27PE±ABT-737 in melanoma cells. (A) FEMX, Melmet-5 and MelRM cells were subjected to 9.2.27PE (100 ng/ml)+ABT-737 (10 mM) for 16 and 24 h before subjected to flow cytometric analysis using Calcium GreenTM-1. The 9.2.27PE enhanced calcium release caused by ABT-737. The data shown are the mean 6 SD for at least three independent experiments. (B) MelRM, MelRMshCtr and MelRMshMcl- 1 were subjected to 9.2.27PE (100 ng/ml)+ABT-737 (10 mM). [Ca2+]i levels, mitochondrial membrane potential and cell viability was measured after 12 h. Knockdown of Mcl-1 using shRNA enhanced the calcium release and decreased cell viability caused by ABT-737, an effect which could not be enhanced by 9.2.27PE. The data shown are the mean 6 SD. P12 = passage 12, the highest passage used for this experiment. doi:10.1371/journal.pone.0024012.g005 in melanoma patients. The Bcl-2 family proteins may serve as an important and widely applicable target for anti-cancer immuno- therapeutic strategies, and spontaneous cellular immune responses against the Bcl-2 family proteins have been identified as frequent features in cancer patients [28]. These observations underscore that the Bcl-2 family proteins are natural targets for the immune PLoS ONE | www.plosone.org 9 September 2011 | Volume 6 | Issue 9 | e24012