(1S,2S,3E,7E,11E)-3,7,11,15-Cembratetraen-17,2-olide, a cembrenolide diterpene from soft coral Lobophytum sp., inhibits growth and induces apoptosis in human colon cancer cells through reactive oxygen species generation.

Institute of Medical Sciences, School of Medicine, Jeju National University, Jeju 690-756, Republic of Korea.
Biological & Pharmaceutical Bulletin (Impact Factor: 1.85). 01/2012; 35(7):1054-63. DOI: 10.1248/bpb.b11-00024
Source: PubMed

ABSTRACT We observed that (1S,2S,3E,7E,11E)-3,7,11,15-Cembratetraen-17,2-olide (LS-1), marine cembrenolide diterpene, inhibited growth and induced apoptosis in colon cancer cells via a reactive oxygen species (ROS) dependent mechanism. Treatment of HT-29 cells with LS-1 resulted in ROS generation, which was accompanied by disruption of mitochondrial membrane potential, cytosolic release of cytochrome c, sub-G1 peak accumulation, activation of Bid, caspase-3, -8, and -9, and cleavage of poly(ADP-ribose) polymerase (PARP) along with the suppressive expression of B cell lymphoma-2 (Bcl-2). All these effects were significantly blocked on pretreatment with the ROS inhibitor N-acetylcysteine (NAC), indicating the involvement of increased ROS in the proapoptotic activity of LS-1. Moreover, we showed that LS-1 induced the phosphorylation of c-Jun N-terminal kinase (JNK) and dephosphorylation of p38, extracellular signal-regulated kinase (ERK), Akt, Src and signal transducer and activator of transcription (STAT)3, which were effectively attenuated by NAC. In addition, the expressions of antioxidant catalase and glutathione peroxidase were abrogated by treatment using LS-1 with or without NAC. These findings reveal the novel anticancer efficacy of LS-1 mediated by the induction of apoptosis via ROS generation in human colon cancer cells.

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    ABSTRACT: Chemical examination of a South China Sea soft coral Lobophytum sp. led to the isolation of three new α-methylene-γ-lactone-containing cembranoids, (1R*,3R*, 4R*,14R*,7E,11E)-3,4-epoxycembra-7,11,15(17)-trien-16,14-olide (1), (1R*,7S*,14S*,3E, 11E)-7-hydroperoxycembra-3,8(19),11,15(17)-tetraen-16,14-olide (2), and (1R*,7S*,14S*, 3E,11E)-18-acetoxy-7-hydroperoxycembra-3,8(19),11,15(17)-tetraen-16,14-olide (3), along with eleven known analogues 4-14. The structures of the new compounds were elucidated through extensive spectroscopic analysis, including 1D and 2D NMR data. Compounds 1-3 exhibited moderate cytotoxic activity against the selected tumor cell lines. Moreover, 2 and 3 were found to be moderate inhibitors against the bacteria S. aureus and S. pneumoniae.
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