Studies have shown that
matrine has antitumor activity against many types of
cancers. However, the direct target in
cancer cells of its anticancer effect has not been identified. The purpose of this study was to find the molecular target of
matrine to inhibit the proliferation of
cancer cells and explore its mechanism of action. Herein we showed that
matrine inhibited the proliferation of
cancer in vitro and in vivo. Pull-down assay with
matrine-amino coupling resins and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) identified Src as the target of
matrine. Cellular thermal shift assay (CETSA) and
drug affinity responsive target stability (DARTS) provided solid evidences that
matrine directly bound to Src. Bioinformatics prediction and pull-down experiment demonstrated that
Src kinase domain was required for its interaction with
matrine and Ala392 in the
kinase domain participated in
matrine-Src interaction. Intriguingly,
matrine was proven to inhibit
Src kinase activity in a non-
ATP-competitive manner by blocking the autophosphorylation of Tyr419 in
Src kinase domain.
Matrine down-regulated the phosphorylation levels of MAPK/ERK, JAK2/STAT3, and PI3K/Akt signaling pathways via targeting Src. Collectively,
matrine targeted Src, inhibited its
kinase activity, and down-regulated its downstream MAPK/ERK, JAK2/STAT3, and PI3K/Akt phosphorylation signaling pathways to inhibit the proliferation of
cancer cells.