Inhibitory Effect of Coffee on Heato Proliferation and Invasion in Culture and on Tumor Growth, Metastasis and Abnormal Lipoprotein Profiles in Hepatoma-Bearing Rats

Abstract

We have already reported that instant coffee powder (ICP) and ICP-loade rat sera could suppress proliferation and invasion of rat ascites hepatoma cell line of AH109A in vitro. In this report, we examined the mechanisms for suppression of tumor cell prolifer-ation and invasion y ICP, and the effect of ICP on in vivo tumor growth, metastasis and abnormal lipoprotein profiles in hepatoma-bearing rats. ICP, when directly added to the cuh ture media, induced cell cycle arrest (elongation of S phase) at a lower concentration (0.3mg/mL) and apoptosis at a higher concentration (0.6-1.2mg/mL). ICP and ICP-loade rat sera showed reactive oxygen species (OS)-scavenging property and canceled the enhance-ment of invasive activity of hepatoma cells induced by OS in vitro. These results suggest that ICP suppresses the proliferation by inducing cell cycle arrest and apoptosis, and the invasion by scavenging ROS and that ICP could retain these properties after their gas-trointestinal absorption. The hepatoma-bearing rats were fed with a 20% casein diet (20C) or 20C supplemented with 0.1% ICP for 14 d. Dietary ICP significantly reduced solid tumor growth and tended to reduce hepatoma metastases to lung and lymphatic nodes, suggesting that ICP could suppress tumor cell proliferation and invasion in vivo. In addition, dietary ICP significantly increased serum high density lipoprotein (HDL)-cholesterol and tended to reduce very low-density and low-density lipoprotein (VLDL+LDL)-cholesterol, resulting in amelioration of abnormal lipoprotein profiles occurred in hepatoma-bearing rats. In conclu-sion, ICP has the ability to induce cell cycle arrest and apoptosis in hepatoma cells and to suppress tumor cell invasion by reducing oxidative stresses in vitro, and it could also exhibit these effects in vivo, leading to the inhibition of tumor growth and metastases.