Dihydromethysticin (DHM), a natural compound derived from Kava, has been reported to be effective against mental disorders and some malignant tu mors. However, little is known about the inhibitory effect of DHM on colorectal cancer (CRC). First, we examined the impact of DHM on human colon cancer cell lines, which demonstrated that DHM inhibits proliferation, migration, and invasion and promotes apoptosis and cell cycle arrest in colon cancer cells in vitro. Using small hairpin RNA, we inhibited nucleotide-oligomerization domain-like receptor subfamily C3 (NLRC3)/phosphoinositide 3-kinase (PI3K) pathway to elucidate the partial signaling of DHM-mediated tumor suppression. Additionally, using an ectopic human CRC model, we verified whether DHM inhibits tumor growth and angiogenesis via the NLRC3/PI3K pathway in vivo. Overall, DHM showed an inhibitory effect on CRC by altering cell proliferation, migration, invasion, apoptosis, cell cycle, and angiogenesis, possibly via the NLRC3/PI3K pathway. Thus, DHM may be a promising candidate for CRC therapy. K E Y W O R D S colorectal cancer, dihydromethysticin, NLRC3 1 | INTRODUCTION Colorectal cancer (CRC) is third most prevailing malignant tumor in the world. In 2016, approximately 134 490 individuals were diagnosed with CRC in the United States, and it was responsible for mortality of more than one-third. 1 In the past few decades, remarkable progress has been made in the treatment of CRC with variety of chemotherapy drugs and immunotherapies constantly emerging. However, due to drug resistance and dose-limiting toxicity, limited success has been achieved in treating advanced CRC. 2 Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; CDK4, cyclin-dependent kinase 4; CK, creatine kinase.; CRC, colorectal cancer; DAPI, 4′, 6-diamidino-2-phenylindole; DHM, dihydromethysticin; H&E staining, hematoxylin and eosin staining; JNK, c-Jun NH2 terminal kinase; LDH, lactate dehydrogenase; MMP2, matrix metallopeptidase 2; MMP9, matrix metallopeptidase 9; mTOR, mammalian target of rapamycin; NF-κB, nuclear factor-kappa B; NLRC3, nucleotide-oligomerization domain-like receptor subfamily C3; PBS, phosphate-buffered saline; PI3K, phosphoinositide 3-kinase; RIPA, radio immunoprecipitation assay; TUNEL, terminal dUTP nick-end labeling; VEGF, vascular endothelial growth factor. Huayang Pan, Fukai Liu, and Jinge Wang contributed equally to this work. Terminal dUTP nick-end labeling (TUNEL) assay was performed according to the manufacturer's instructions (Roche, Shanghai, China). CRC cells were washed once with PBS, fixed with formalin for 30 minutes, and washed again with PBS. Cells were then suspended 576 | PAN ET AL.