OC-77: ANTITUMORAL EFFECT OF ST II, A CYTOLYSIN ISOLATED FROM SEA ANEMONE Stichodactyla helianthus, ON TUMORAL CELLS in vitro AND in vivo

J Pharm Pharmacogn Res 3(suppl. 1): S89, 2015

Proceedings of the 4th International Symposium on Pharmacology of Natural Products FAPRONATURA 2015  September 21st-25th, 2015; Cuban Society of Pharmacology. Topes de Collantes, Sancti Spiritus, Cuba.

Oral Communication

OC-77: ANTITUMORAL EFFECT OF ST II, A CYTOLYSIN ISOLATED FROM SEA ANEMONE Stichodactyla helianthus, ON TUMORAL CELLS in vitro AND in vivo

Soto C1, del Valle A1, Blanco R2, Bencomo A2, Rodríguez JC3, Lanio M1, Álvarez C1, Hernández AM2.

1Center for Protein Studies, Faculty of Biology, Havana University, Cuba. E-mail: carmensoto@fbio.uh.cu
2Center for Molecular Immunology, Havana, Cuba.
3National Institute of Oncology and Radiobiology, Havana, Cuba.

 

Introduction: SticholysinII (StII) is a cytolysin produced by anemone Stichodactyla helianthus with high affinity for sphingomyelin, which induces cell death by forming pores in membranes. This research explores the binding of StII to lipids, the mechanism that mediates its cytotoxicity on tumor cells in vitro and its effect on a solid tumor model in vivo. Material and Methods: StII association to lipids was studied by Dot blott Immunostaining, monolayers, liposome, docking and molecular dynamics. Sticholysin cytotoxic activity against Raji cells was tested by MTT and propidium iodide incorporation assays. Caspase activity was measured by caspase kit. Cytoskeleton contribution to cell death was studied in the presence of cytochalasin. The effect of toxin on mitochondria was studied with JC-1 probe. Morphological alterations and apoptotic bodies formation induced by StII in Raji cells were analyzed by optical microscopy. Contribution of MAPKs to cytotoxic effect of StII was studied by MTT and Western blot. Anti-tumor effect in vivo was study in a subcutaneous X63 tumor model in Balb/c mice. Results: Binding intensity in a decreasing order was sphingomyelin, phosphatidylcholine, ceramide, gangliosides. Pore formation in Raji cells leads to cellular swelling and the release of cytoplasmic components. Cellular death was inhibited in presence of cytochalasin. Toxin did not induce caspase activation or apoptotic bodies’ formation suggesting a mechanism of necrosis. Cytotoxicity induced by St II in the presence of ERK pathway inhibitor, decreased. In addition, toxin induces activation of the pathway, which was demonstrated by an increase in the ERK1/2 phosphorilation levels. The intra-tumoral injection of StII significantly reduced the tumor volume and induces extense necrosis areas and neutrophyl infiltration, without systemic toxicity. Conclusions: St II induces cell death necrosis, which induces partial mitochondrial depolarization and needs actin polymerization. This toxin showed a potent anti-tumor effect in vivo.

 

Citation Format: Soto C, del Valle A, Blanco R, Bencomo A, Rodríguez JC, Lanio M, Álvarez C, Hernández AM (2015) Antitumoral effect of ST II, a cytolysin isolated from sea anemone Stichodactyla helianthus, on tumoral cells in vitro and in vivo. [Abstract]. In: Proceedings of the FAPRONATURA 2015; 2015 Sep 21-25; Topes de Collantes, Sancti Spiritus: CSF. J Pharm Pharmacogn Res 3(Suppl. 1): S89. Abstract nr OC-77.