(P03-049-23) Anticancer Activity of Natural Products in Humulus lupulus (Hops) in Human Colorectal Cancer Cells

Objectives: Hop plant is a key ingredient in beer and contains bioactive compounds that possess biological benefits. Xanthohumol (XN), the most abundant prenylated flavonoid, has been tested for treatment of a broad range of chronic diseases including obesity, diabetes, and cancer. In addition, several other compounds including isoxanthohumol (IXN), 8-prenylnaringenin (8-PN), and tetrahydroxanthohumol (TXN) have been derived from XN. Colorectal cancer is one of the leading causes of cancer-related mortality worldwide. This study investigated the anti-cancer activity of these natural hops compounds and the mechanism of their activity in human colorectal cancer cells.

Methods: XN, IXN and 8-PN were purchased from Cayman chemical and TXN was kindly provided by Hopsteiner Inc. Human colorectal cancer cell lines (SW480, SW620, and HCT116) were incubated with different concentrations of XN, TXN, IXN, and 8-PN. Cell viability was measured by MTT assay. Cell cycle phase was measured by flow cytometry. Apoptosis was analyzed by FACS analysis after PI and Annexin V staining. Western blotting was performed to measure the expression of proteins. ROS release was detected using Promega Ros-Glo H2O2 kit.

Results: MTT assay showed all hop compounds (XN, IXN, 8-PN, and TXN) significantly suppressed viability of human colorectal cancer cell lines (SW480, HCT116, and SW620). Percentage inhibition of cell viability was much higher in XN and TXN. Thus we selected these two compounds for further studies. Flow cytometry indicated that TXN and XN led to significant induction of S phase arrest with slight induction of G2/M phase arrest. An apoptotic assay showed a huge induction of early and late apoptosis in the cells treated with TXN and XN at a dose of 12 µM and 18 µM. Western blotting showed increased cleaved PARP and induction of CHOP expression. In addition, a dose-dependent increase in intracellular ROS was observed in the cells treated with 12 and 18 µM of TXN and XN. Taken together, we proposed an anti-cancer mechanism by TXN and XN including induction of ROS release, ER stress, and apoptosis in human colorectal cancer cells.

Conclusions: Our data indicate that TXN and XN could be promising agents in hops for the prevention of human colorectal cancer.

Funding Sources: No funding source