title: Inhibition of epidermal growth factor receptor signaling pathway by delphinidin, an anthocyanidin in pigmented fruits and vegetables.
abstract: Inhibitors of the epidermal growth factor receptor (EGFR) have generated considerable hope for cancer treatment, specifically for lung and breast cancers. Therefore, identification of a natural, nontoxic agent(s) as an inhibitor of EGFR is of considerable importance. Delphinidin, an anthocyanidin present in pigmented fruits and vegetables, possesses potent antioxidant and antiproliferative properties. In our study, employing EGFR positive breast cancer AU-565 cells and immortalized MCF-10A cells, we evaluated the effect of delphinidin on EGFR and its downstream signaling pathways. Delphinidin (5-40 microM; 3 hr) treatment of both AU-565 cells and MCF-10A cells inhibited the (i) phosphorylation of EGFR, (ii) activation of PI3K, (iii) phosphorylation of AKT and MAPK. Further, delphinidin treatment of AU-565 cells inhibited EGF-induced autophosphorylation of EGFR, AKT and MAPK, activation of PI3K and cell invasion. We then compared the growth inhibitory effects of delphinidin (5-40 microM; 48 hr), and found that it resulted in a decrease in cell growth of AU-565 and MCF-10A cells but had only minimal effects on normal mammary epithelial 184A1 cells. Treatment of AU-565 cells with delphinidin resulted in (i) induction of apoptosis, (ii) cleavage of PARP protein, (iii) activation of caspase-3 and (iv) downregulation of Bcl-2 with an increase in the expression of Bax. In summary, our study identifies a naturally occurring dietary agent delphinidin as an effective inhibitor of EGFR signaling in breast cancer cells. We suggest that delphinidin could be developed as an agent for the management of EGFR positive human cancers.
authors.affiliation: Department of Dermatology, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: Farrukh
authors.initials: F
authors.lastname: Afaq
authors.forename: Najia
authors.initials: N
authors.lastname: Zaman
authors.forename: Naghma
authors.initials: N
authors.lastname: Khan
authors.forename: Deeba N
authors.initials: DN
authors.lastname: Syed
authors.forename: Sami
authors.initials: S
authors.lastname: Sarfaraz
authors.forename: Mohammad Abu
authors.initials: MA
authors.lastname: Zaid
authors.forename: Hasan
authors.initials: H
authors.lastname: Mukhtar
mesh_terms: D000872:Anthocyanins / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000737:chemistry*; D020868:Gene Silencing; D006801:Humans; D018613:Microscopy, Confocal; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000187:drug effects*; D014675:Vegetables / Q000737:chemistry*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D034741:RNA, Small Interfering; D051028:bcl-2-Associated X Protein; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; C017185:delphinidin