Abstract 4244: Inhibition of HER2 and IGF2 triggers cell death in trastuzumab-resistant HER2 positive JIMT1 cells

Abstract

Abstract Breast cancer is the second leading cause of death in women. Overexpression of Human Epidermal Growth Factor Receptor 2 (HER2) is detected in 20-30% of breast cancers. Increased levels of HER2 are linked to poor prognosis, more aggressive phenotype, and resistance to chemotherapy and hormonal treatment. HER2 is part of a four member family of cell surface receptors that are implicated in transmission of signals controlling cell growth and differentiation. HER2 has an intracellular domain with tyrosine kinase catalytic activity and dimerization of HER2 activates the MAP kinase and AKT pathways. HER2 receptor also heterodimerizes with the IGF1 receptor(IGF1R) in trastuzumab-resistant cell lines. The insulin-like growth factor 2 (IGF2) has an important role in fetal and cancer development signaling through the IGF1R, insulin receptor (InsR), and cross-talk with the estrogen receptor alpha and beta (ERα, ERß). Previous findings in our lab demonstrate an increased expression of IGF2 in trastuzumab-resistance cell line JIMT1 when compared to trastuzumab-sensitive cell lines BT474, SKBR3, and ZR75-30. We hypothesis that to overcome trastuzumab-resistance in JIMT1 cell lines, dual inhibition of HER2 and IGF2 is necessary to induce cell death. When JIMT1 cells were treated with resveratrol, both HER2 and IGF2 mRNA and protein levels were reduced and a decrease in cell viability was observed. We also analyzed the phosphorylation levels of HER2 and IGF1R. Our studies suggest that blocking both HER2 and IGF2 is necessary to decrease cell viability in trastuzumab-resistant JIMT1 cells. Citation Format: Xousaen M. Helu, Daisy De Leon. Inhibition of HER2 and IGF2 triggers cell death in trastuzumab-resistant HER2 positive JIMT1 cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4244. doi:10.1158/1538-7445.AM2014-4244