EGFR Inhibition by Curcumin in Cancer Cells: A Dual Mode of Action.

Epidermal Growth Factor Receptor (EGFR) is an important target of anticancer therapy. Nowadays, the search for new molecules inhibiting this receptor is turning toward natural substances. One of the most promising natural compounds that have shown an anti-EGFR activity is curcumin, a polyphenol found in turmeric. Its effect on the receptor kinase activity and on the receptor autophosphorylation has been already described, but the mechanism of how curcumin interacts with EGFR is not fully elucidated. We demonstrate that the mode of action of curcumin is dual. This polyphenol is able to inhibit directly but partially the enzymatic activity of the EGFR intracellular domain. The present work shows that curcumin also influences the cell membrane environment of EGFR. Using biomimetic membrane models, we show that curcumin insertion into the lipid bilayer leads to its rigidification. Single particle tracking analyses performed in the membrane of A431 cancer cells confirmed that this effect of curcumin on the membrane slows down the receptor diffusion. This is likely to affect the receptor dimerization and, in turn, its activation.