Anti-Cancer and Pro-Immune Effects of Lauric Acid on Colorectal Cancer Cells.

Lauric acid (LAA) is a 12-carbon medium-chain fatty acid that reportedly has antitumor and muscle-protecting effects. However, the details of these antitumor effects remain unclear. Therefore, in this study, we investigated the mechanism underlying the antitumor effects of LAA in CT26 and HT29 colorectal cancer (CRC) cell lines. Our in vitro findings demonstrated that LAA suppressed CRC cell proliferation, induced mitochondrial oxidative stress (reactive oxygen species (ROS)), inhibited oxidative phosphorylation (OXPHOS), and induced apoptosis. Moreover, in vivo analysis of LAA showed a more pronounced antitumor effect in CT26 cells in a syngeneic mouse tumor model than in vitro; therefore, we further investigated its impact on host antitumor immunity. We observed that LAA increased the number of effector T cells in mouse tumors, while in vitro LAA activated mouse splenocytes (SplC) and promoted OXPHOS. In two-dimensional co-culture of SplC and CT26 cells, LAA induced cell death in cancer cells. In three-dimensional co-culture, LAA promoted SplC infiltration and suppressed the formation of tumor spheres. Thus, LAA may exert antitumor effects through increased ROS production in cancer cells and effector T cell activation via increased energy metabolism. These results suggest that LAA, when used in combination with existing anti-cancer drugs, is likely to exhibit sensitizing effects in terms of both antitumor and antitumor immune effects, and future clinical studies are anticipated.