Cytotoxicity of goniothalamin enantiomers in renal cancer cells: involvement of nitric oxide, apoptosis and autophagy.

Abstract

Goniothalamin is a styryllactone synthesized by plants of the genus Goniothalamus. The biological activities of this molecule, particularly its anti-protozoan, anti-fungal, and larvicidal properties, have received considerable attention. In this work, we investigated the action of the natural and synthetic enantiomers (R)-goniothalamin (1) and (S)-goniothalamin (ent-1) on cell viability, nitric oxide synthase (NOS) expression and activity, and the expression of selected proteins involved in apoptosis and autophagy in renal cancer cells. Both compounds were cytotoxic and decreased the mitochondrial function of renal cancer cells. However, the enantiomers differentially affected the expression/activity profiles of some signaling pathway mediators. Ent-1 (4 nM) was more potent than 1 (6.4 microM) in inhibiting constitutive NOS activity (54% and 59% inhibition, respectively), and both enantiomers decreased the protein expression of neuronal and endothelial NOS, as assessed by western blotting. Ent-1 and 1 caused down-regulation of Ras and TNFR1 and inhibition of protein serine/threonine phosphatase 2A (PP2A). Compound 1 markedly down-regulated Bcl2, an anti-apoptotic protein, and also induced PARP cleavage. Despite inducing an expressive down-regulation of Bax, ent-1 was also able to induce PARP cleavage. These results suggest that these compounds caused apoptosis in renal cancer cells. Interestingly, ent-1 enhanced the expression of LC3, a typical marker of autophagy. NFkappaB was down-regulated in 1-treated cells. Overall, these results indicate that the anti-proliferative activity of the two enantiomers on renal cancer cells involved distinct signaling pathways, apoptosis and autophagy as dominant responses towards 1 and ent-1, respectively.

• Authors: Angelo de Fátima, Willian F Zambuzzi, Luzia V Modolo, Christiane A B Tarsitano, Fernanda R Gadelha, Stephen Hyslop, João Ernesto de Carvalho, Ione Salgado, Carmen V Ferreira, Ronaldo A Pilli
• Journal: Chemico-biological interactions (Chem Biol Interact) Vol. 176 Issue 2-3 Pg. 143-50 (Nov 25 2008) ISSN: 1872-7786 [Electronic] Ireland
• PMID: 18771661 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Proto-Oncogene Proteins c-bcl-2
• Pyrones
• Receptors, Tumor Necrosis Factor, Type I
• Nitric Oxide
• goniothalamin
• Nitric Oxide Synthase
• Protein Phosphatase 2
• ras Proteins

Topics

• Apoptosis (drug effects)
• Autophagy (drug effects)
• Cell Proliferation (drug effects)
• Cell Survival (drug effects)
• Dose-Response Relationship, Drug
• Down-Regulation (drug effects)
• Drug Screening Assays, Antitumor
• Humans
• Kidney Neoplasms (drug therapy, pathology)
• Mitochondria (drug effects, metabolism)
• Molecular Conformation
• Nitric Oxide (metabolism)
• Nitric Oxide Synthase (metabolism)
• Oxygen Consumption (drug effects)
• Protein Phosphatase 2 (antagonists & inhibitors)
• Proto-Oncogene Proteins c-bcl-2 (drug effects, metabolism)
• Pyrones (chemical synthesis, chemistry, pharmacology)
• Receptors, Tumor Necrosis Factor, Type I (drug effects, metabolism)
• Stereoisomerism
• Tumor Cells, Cultured
• ras Proteins (drug effects, metabolism)