Combination treatment of ABT-737 with autophagy inhibitors results in decreased proliferation in SCLC cell lines. Cells were plated in 96-well plates and treated with DMSO, ABT-737, chloroquine (CQ), and the combination of ABT-737 and chloroquine. At 72 hours post-treatment they were assayed using the MTS cell proliferation assay. Commercially available cell lines are shown in A and cell lines derived from low passage cultures of primary patient xenografts in B. Doses chosen were based on initial determination of IC50 values and were as follows: H82 (17 μM ABT-737, 16.5 μM chloroquine), H209 (0.5 μM ABT-737, 20 μM chloroquine), H345 (0.25 μM ABT-737, 94 μM chloroquine), LX22 (6 μM ABT-737, 40 μM chloroquine), and LX33 (0.8 μM ABT-737, 33 μM chloroquine). C. Similar treatments were performed combining ABT-737 and 3-methyladenine, another autophagy inhibitor. 3-methyladenine doses were 5 mM for both lines. Error bars: standard deviation (SD); n = 4.