The EGFR family of receptors sensitizes cancer cells towards UV light

A combination of bioinformatics, biophysical, advanced laser studies and cell biology lead to the realization that laser-pulsed UV light stops cancer growth and induces apoptosis. We have previously shown that laser-pulsed UV (LP-UV) illumination of two different skin-derived cancer cell lines both over expressing the EGF receptor, lead to arrest of the EGFR signaling pathway. We have investigated the available sequence and experimental 3D structures available in the Protein Data Bank. The EGF receptor contains a Furin like cystein rich extracellular domain. The cystein content is highly unusual, 25 disulphide bridges supports the 621 amino acid extracellular protein domain scaffold (1mb6.pdb). In two cases a tryptophan is neighboring a cystein in the primary sequence, which in itself is a rare observation. Aromatic residues is observed to be spatially close to all observed 25 disulphide bridges. The EGF receptor is often overexpressed in cancers and other proliferative skin disorders, it might be possible to significantly reduce the proliferative potential of these cells making them good targets for laser-pulsed UV-light treatment. The discovery that UV light can be used to open disulphide bridges in proteins upon illumination of nearby aromatic amino acids was the first step that lead to the hypothesis that UV light could modulate the structure and therefore the function of these key receptor proteins. The observation that membrane receptors (EGFR) contained exactly the motifs that are sensitive to UV light lead to the prediction that UV light could modify these receptors permanently and stop cancer proliferation. We hereby show that the EGFR family of receptors has the necessary structural motifs that make this family of proteins highly sensitive to UV light.