Figure 2.

Luteolin inhibition of receptor-mediated tumor progression.

Notes: Involvement of luteolin (green) in modifying processes necessary for metastasis. Notch activation results in removal of the intracellular domain of the membrane-bound Notch receptor, creating the NICD. NICD is blocked by luteolin through an undetermined mechanism. Wnt/β-catenin inhibits GSK3 activity upon activation. Luteolin blocks Wnt-induced phosphorylation of GSK3, and thus prevents GSK3 inhibition. Luteolin has been shown to inhibit RTK activities and their downstream effectors (see text for specific RTKs and associated effector responses). Possible outcomes for each receptor pathway are in the corresponding colored boxes. Intracellular proteins color-coded as protein kinases (blue), TCFs (gray), and other proteins (brown). Dashed line represents possible luteolin interaction.

Abbreviations: EMT, epithelial–mesenchymal transition; JAK, Janus kinase; Lu, luteolin; NICD, notch intracellular domain; RSK, ribosomal S6 kinase; RTK, receptor tyrosine kinase; TCF, transcription factor.