PO-406 The olive-based oleocanthal as a dual HER2-MET inhibitor for the control of breast cancer

Abstract

IntroductionDysregulation of the receptor tyrosine kinases HER2 and Met correlate with poor breast cancer prognosis and invasive aggressive profile. Met amplification proved to be the HER2-dependent tumours inevitable escape mechanism from the anticancer effects of targeted therapies including trastuzumab, and small-molecule RTK inhibitors like lapatinib, gefitinib, and erlotinib. Dual HER2-Met inhibition is expected to be effective and less likely to develop resistance.As a results these unavoidable critical conditions now creates a high demand either to design or identified a lead molecule that can inhibit Met/HER2 combinedly.Material and methodsTo validate the hypothesis molecular modelling used to identify a Met/HER2 hit from a wide library of natural compounds. Identified hits via virtual screening further validated through cell free Z-LYTE and cell viability assay in a wide range of cancer cell lines. In addition, cytotoxicity tested in non-cancer cell line. Western blot and flowcytometry analysis used to validate the activity of the identified hit at molecular level. Finally, to push the hit into a lead rank used in vivo athymic nude mice in two different xenograft model such as MDA-231, BT-474 in both IP and oral administration.Results and discussionsOC showed typical type-I binding mode at Met ATP kinase domain. OC aldehydes, ester, phenol groups showed critical interactions at activation loop ASP1222/TYR1230 and hinge region PRO1158/MET1160. OC uniquely interacting HER2 kinase domain at hinge region MET801, PHE864, THR862 and SER783. OC showed low-µM inhibitory activities against both Met and HER2 kinases in cell-free Z-LYTE assays. In vitro, OC showed inhibition of the proliferation and migrations in BC cells BT-474, SK-BR-3, MDA-MB-231 at low μM IC50 dose range. OC effect on HER2 and MET were further confirmed by Western blotting, flowcytometry studies. OC potently induced autophagy in SK-BR-3 by upregulation of LCA/B, Atg-3, Atg-7, Atg-16L within 6–12 hour treatment. OC had no effect on the viability of the non-tumorigenic MCF-12A and RSC 96 cells. In vivo, 5–10 mg/kg oral/ip dose range of OC potently inhibited 65%–90% tumour growth both BT-474 and MDA-MB-231 BC cells xenograft models. This was further confirmed by significant reductions of Ki-67, CD31in treated animal tumours by IHC.ConclusionCollectively, these promising results suggest that OC is a unique dual Met/HER2 inhibitory lead entity with excellent therapeutic potential to control breast malignancies with aberrant Met or HER2 activity.