Oroxylin A suppressed colorectal cancer metastasis by inhibiting the activation of the TGF-β/SMAD signal pathway.

Metastatic colorectal cancer continues to have a high fatality rate, with approximately only 14% of patients surviving more than 5 years. To improve the survival rate of these patients, the development of new therapeutic drugs is a priority. In this study, we investigated the effects of Oroxylin A on the metastasis of human colorectal cancer cells and its potential molecular mechanism. This study utilised CCK8 assay, transwell assay, flow cytometry, western blot analysis, molecular docking, HE staining, immunofluorescence staining, and xenograft models. The proliferation, migration, and invasion of colon cancer cells were effectively suppressed by Oroxylin A in a dose-dependent manner. Oroxylin A has the potential to inhibit the process of epithelial‒mesenchymal transition (EMT) by upregulating the expression of E-cadherin, a marker associated with epithelial cells, while downregulating the levels of N-cadherin, Snail, vimentin, and slug, which are markers associated with mesenchymal cells. In addition, 200 mg/kg of Oroxylin A inhibited the growth of colorectal tumours. Molecular docking technology revealed that Oroxylin A can bind to TGFβ and inhibit the activation of the TGFβ-smad signalling pathway. The overexpression of TGFβ weakened the inhibitory effect of Oroxylin A on the proliferation, migration, and invasion of human colorectal cancer cells, as well as the promoting effect on apoptosis. Oroxylin A inhibited the activation of the TGF-smad signalling pathway and the EMT process, thereby suppressing the migration and invasion of human colorectal cancer cells.