Fig. 3.

Activity data and cell cycle studies. (A) Seriniquinone (1) induces cell death in HCT-116 cells in a concentration- and time-dependent manner. (B) Time-course studies show that the optimal activity from 1 in HCT-116 cells is obtained after constant treatment with 1 over 24 h. (C) Western blot analysis confirms compromise of autophagosome maturation by a dose-dependent increase in the levels of LC3A-II and LC3B-II (two posttranslationally modified light chain 3 [LC3] protein isoforms whose levels increase during autophagy) after treatment of HCT-116 cells with 1 for 24 h. This response was significantly greater than negative (–, DMSO) and positive (+, 17 µM etoposide) controls. (D) Cell death is accompanied by DNA fragmentation suggesting that apoptotic processes are elicited. (E) Compound 1 induces a dose-dependent arrest during DNA replication as noted by the increase in S staged cells. Western blot analyses for selected: (F) cyclins, as given by A = cyclin A, B = cyclin B1, D1 = cyclin D1, D2 = cyclin D2, D3 = cyclin D3, E = cyclin E, E2 = cyclin E2, H = cyclin H; or (G) apoptotic markers, as given by 3 = caspase 3, c-3 = cleaved caspase 3, 7 = caspase 3, c-7 = cleaved caspase 7, 9 = caspase 9, c-9 = cleaved caspase 9, P = PARP, c-P = cleaved PARP, in lysates prepared from HCT-116 cells that were treated with 1 for 24 h. Negative and positive controls are given by (–) DMSO and (+) 17 µM etoposide, respectively. Actin was used as a loading control. Unless noted otherwise, all experiments were conducted in HCT-116 cells and concentrations are provided in µM. * denotes P < 0.05.