In vitro impact of a whey protein isolate (WPI) and collagen hydrolysates (CHs) on B16F10 melanoma cells proliferation

Background: Porcine skin gelatine presented anti-tumoral effect on murine hepatoma cells (MH134), inducing programmed cell death (apoptosis). Whey proteins (mainly lactoferrin) have been investigated for cancer prevention and treatment. Objective: Investigation of the inhibitory capacity on melanoma cells (B16F10) proliferation and the influence on % distribution of cell cycle phases, in the presence of various concentrations of whey protein isolate (WPI), bovine Collagen hydrolysate (BCH) or its fractions. Methods: The permeate fraction BCH-P1 (molecular mass, MM 2.5 kDa) was further fractionated into five retentate fractions (R1-R5) by ultrafiltration membranes and into four fractions (F1-F4) by reverse phase chromatography. The permeate BCH-P1 and all its fractions were comparatively tested against a negative control (B16F10 cells + culture medium), and also against a positive control (B16F10 + culture medium + WPI). Results: The inhibitory concentrations for 50% of B16F10 cells (IC50) ranged from 0.19 to 156.9 mg/mL for all these proteins evaluated. The most inhibitory fractions of the BCH hydrolysate were BCH-P1 and F1-F4 with IC50 concentrations below 1 mg/mL. Changes in cell cycle phases were characterized by a general decrease in the G2/M phase that emphasizes growth arrest, some increase in phase S (BCH-P1 and F4) but a strong increase in G0/G1 phase for BCH-P1 and F4. Caspase-3 expression increased significantly in all media containing F and R fractions, and also in the presence of BCH or WPI. Apoptosis was extremely high at low concentration (400 mu g/mL) of the F1-F3 fractions. Conclusion: It is suggested that a mechanism for tumorigenesis inhibition may involve the caspases cascade and apoptosis. (C) 2009 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.