Lycorine is a powerful anti-cancer agent against various cancer cell lines with minor side effects. However, the detailed mechanisms of its effects in colorectal cancer (CRC) remain unclear. In this study, we investigated the function and mechanism of lycorine against CRC both in vitro and in vivo. Molecular docking modeling was used to identify potential inhibitory targets of lycorine in CRC. Cell viability was measured using the Cell Counting Kit-8 assay, and apoptosis was measured using flow cytometry. Autophagosomes were examined using transmission electron microscopy and confocal microscopy. HCT116-derived xenografts were constructed to analyze the effect of lycorine in CRC in vivo. Using the CDOCKER algorithm, we determined that lycorine has four interactions with the conserved domain of mitogen-activated protein kinase kinase 2 (MEK2). This prediction was further confirmed by the degradation of phosphorylated MEK2 and its downstream targets after lycorine treatment, and MEK2 overexpression abolished lycorine-induced autophagy-associated apoptosis. Additionally, we revealed that the combination of vemurafenib and lycorine had better effects in CRC models in vitro and in vivo than monotherapy. Our findings identified lycorine as an effective MEK2 inhibitor and suggested that the combination of lycorine and vemurafenib could be used to treat CRC.
Keywords: apoptosis; colorectal cancer; lycorine; vemurafenib.