Studies on the mechanisms of tumour inhibition by fractions from two species of Cat's Claw

South America has two predominant species of Cat's Claw (Uña de Gato), Uncaria tomentosa and U. guianensis, which are used in traditional medicine to treat inflammation and cancer. We have shown that their anti-tumour activity may be due, at least in part, to a reduction in pro-tumoural inflammatory processes in the tumour microenvironment, specifically to a reduction in inflammatory mediators (TNF, IL-6, nitric oxide and prostaglandins) and in infiltration by inflammatory cells of the primary tumour [1]. The aim of this study was to determine whether the two active subfractions, Sam A1 from U. tomentosa and Ug AIV from U. guianensis, also inhibited two other key processes involved in tumour growth and metastasis, specifically cell-cell adhesion and migration. These fractions were obtained by bioassay-guided fractionation following these steps: a) extraction in ethanol, b) solid/liquid extraction in different solvents, c) size exclusion chromatography, d) high pressure liquid chromatography. Sam A1 and Ug AIV did not affect the expression of the adhesion molecules ICAM-1 or VCAM-1 in liver sinusoidal endothelial cells (LSEC) by flow cytometry nor did they alter the adhesion of fluorescent 4T1 tumour cells to LSEC in co-culture. However, both preparations reduced the migration of tumour cells (4T1) and endothelial cells (LSEC) by approximately 40% at 10 mg/ml in a 24h scratch assay. Our results indicate that the effect of the two subfractions on migration, which plays a fundamental role in tumour cell invasion and angiogenesis, may contribute to their overall antitumour activity.

Acknowledgements: Grant MC 20070000881 from the Misión Ciencia programme, FONACIT, Venezuela.

Keywords: Uncaria, inflammation, cancer, migration, adhesion

References:

[1] Urdanibia, I. et al. (2013)J Ethnopharmacol 150 1154 – 1162.