Interaction of holothurian triterpene glycoside with biomembranes of mouse immune cells.
ABSTRACT The in vitro interactions between triterpene glycoside, cucumarioside A(2)-2, isolated from the Far-Eastern holothurian Cucumaria japonica, and mouse splenocyte and peritoneal macrophage biomembranes were studied. Multiple experimental approaches were employed, including determination of biomembrane microviscosity, membrane potential and Ca(2+) signaling, and radioligand binding assays. Cucumarioside A(2)-2 exhibited strong cytotoxic effect in the micromolar range of concentrations and showed pronounced immunomodulatory activity in the nanomolar concentration range. It was established that the cucumarioside A(2)-2 effectively interacted with immune cells and increased the cellular biomembrane microviscosity. This interaction led to a dose-dependent reversible shift in cellular membrane potential and temporary biomembrane depolarization; and an increase in [Ca(2+)](i) in the cytoplasm. It is suggested that there are at least two binding sites for [(3)H]-cucumarioside A(2)-2 on cellular membranes corresponding to different biomembrane components: a low affinity site match to membrane cholesterol that is responsible for the cytotoxic properties, and a high affinity site corresponding to a hypothetical receptor that is responsible for immunostimulation.
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ABSTRACT: Many marine triterpene glycosides have in vitro and in vivo activities with very low toxicity, suggesting that they are suitable agents for the prevention and treatment of different diseases, particularly cancer. However, the molecular mechanisms of action of natural marine compounds in cancer, immune, and other various cells are not fully known. This review focuses on the structural characteristics of marine triterpene glycosides and how these affect their biological activities and molecular mechanisms. In particular, the membranotropic and membranolytic activities of frondoside A and cucumariosides from sea cucumbers and their ability to induce cytotoxicity and apoptosis have been discussed, with a focus on structure-activity relationships. In addition, the structural characteristics and antitumor effects of stichoposide C and stichoposide D have been reviewed along with underlying their molecular mechanisms.Frontiers in Chemistry 09/2014; 2:77.