Abstract P3-07-07: The pan-HER inhibitor, neratinib and wingless-type MMTVs (Wnt)/Wnt regulators in human breast cancer; a biological and clinical perspective
Authors: Owen S , Ruge F , Lalani AS , Avogadri-Connors F , Bryce RP , Davies E , Jiang WG 
Published: February 2018

Abstract
Background. Neratinib is an orally available tyrosine kinase inhibitor that irreversibly binds and inhibits EGFR, HER2 and HER4 receptor tyrosine kinases. Neratinib has been shown to have clinical activity in HER2-amplified or overexpressed breast cancers and those with HER2 mutations. However, there are indications that it may also work on other subtypes that are not strongly positive for the receptors. The present study first screened the effects of neratinib on a range of kinase targets and identified that the Wnt signalling components are key factors that allow neratinib to interact and targets. These targets were also validated in a cohort of human breast cancer.
Methods. Human breast cancer cohorts (n=124) were tested for the transcript expression of HER family including EGFR, HER2, HER3 and HER4 and a number of Wnt family members and the Wnt signalling regulators, ie. GSK3, Axin-1, Axin-2 and β-catenin. The expression patterns were analysed against the clinicopathological and survival status of the patients. Neratinib was tested on a panel of breast cancer cell lines including triple negative cells for the effects on cytoxicity, cell growth, matrix adhesiveness and cellular migration. Signalling kinase pathways were screened using an antibody based kinase array. The effect of neratinib on multiple protein kinases was tested on the cell models, together with other kinase inhibitors.
Results. Neratinib had an inhibitory effect on the cellular migration and cell-matrix adhesiveness of breast cancers at non-toxic concentrations, an effect more profound with MCF-7 and T47D cell lines than with BT20 and MDA MB-231 which are negative for the ER/EGFR/HER2 receptors. Of the multiple kinase inhibitors tested, neratinib was found to exert inhibition on cell function in synergy with the Wnt/β-catenin inhibitor (FK535) and GSK3 inhibitor (TWS119). The expression of the HER and Wnt family members, Wnt Inhibitory Factor-1 and Wnt regulators varied in mammary and breast cancer tissues and in their correlation with the clinicopathological factors. Of the aberrantly expressed receptors, Wnts and Wnt regulators, HER-2 and 4 were found to significantly correlate with Wnt10b (p&lt;0.05), EGFR/HER1 was found significantly correlated with GSK3 (p&lt;0.05) and HER-3 with Wnt5a (p&lt;0.03). Furthermore, we identified that the integrated expression pattern of five of these factors, namely EGFR, HER2, HER4, Wnt5 and Wnt Inhibitory Factor-1 formed an expression signature that were significantly linked to the overall survival (survival time 148±3.7 vs 113.7 ±7.5 months for favourable and non-favourable pattern, respectively, p=0.002) and disease free survival (p=0.004) of the patients (median follow-up 120 months)
Conclusion. Neratinib, at non-toxic concentration levels, is a profound inhibitor of the migration and matrix adhesion of breast cancer cells, cell functions linked to the aggressiveness and metastasis of breast cancer cells. Its synergistic effects with the Wnt and GSK3 inhibitor, together with the prognostic value of the HER family/Wnt, indicate that the Wnt pathway together with the HER family forms a new molecular indicator and target when considering neratinib in the treatment patients with breast cancer.
Citation Format: Owen S, Ruge F, Lalani AS, Avogadri-Connors F, Bryce RP, Davies E, Jiang WG. The pan-HER inhibitor, neratinib and wingless-type MMTVs (Wnt)/Wnt regulators in human breast cancer; a biological and clinical perspective [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-07-07.