Zusammenfassung
Bitter acids (BAs) from the hop plant Humulus lupulus L. exhibit multiple beneficial biological properties with promising effects in cancer therapy and prevention, but information regarding the effects on hepatocellular carcinoma (HCC) is missing. Here, we used two different hop bitter acid extracts enriched for either a-acids or beta-acids to obtain insight into whether biological activity ...
Zusammenfassung
Bitter acids (BAs) from the hop plant Humulus lupulus L. exhibit multiple beneficial biological properties with promising effects in cancer therapy and prevention, but information regarding the effects on hepatocellular carcinoma (HCC) is missing. Here, we used two different hop bitter acid extracts enriched for either a-acids or beta-acids to obtain insight into whether biological activity varies between these two groups of BAs. At a concentration of 25 mu g/ml, only the beta-acid rich started to induce aspartate transaminase (AST) release, and a significant increase was detected with 50 mu g/ml of both extracts. Already at lower concentrations both extracts led to a dose-dependent inhibition of proliferation, and migration was suppressed at a concentration as low as 5 mu g/ml in HCC cells. The focus on different signaling pathways revealed an inhibition of ERK1/2 phosphorylation, downregulation of AP-1 activity and an alleviation of nuclear factor kappa B (NF kappa B) activity in HepG2 cells incubated with 5 mu g/ml of both extracts, whereby the beta-acid rich extract showed more pronounced effects. In conclusion, we identified ERK1/2, AP-1 and NE kappa B, which are important factors in tumor development and progression, as targets of hop BAs. Thus, these data suggest the potential use of BAs as functional nutrients for both prevention and treatment of HCC.