Breast tumor Insulin-like growth factor receptor regulates cell adhesion and metastasis: Alignment of mouse single cell and human breast cancer transcriptomics

The acquisition of a metastatic phenotype is the critical event that determines patient survival from breast cancer. Several receptor tyrosine kinases have functions both in promoting and inhibiting metastasis in breast tumors. Although the insulin-like growth factor 1 receptor (IGF-1R) has been considered a target for inhibition in breast cancer, low levels of IGF-1R expression are associated with worse overall patient survival. To determine how reduced IGF-1R impacts tumor phenotype, we used weighted gene correlation network analysis (WGCNA) of METABRIC patient data and identified gene modules specific to cell cycle, adhesion, and immune cell signaling inversely correlated with IGF-1R expression in human breast cancers. Integration of human patient data with data from mouse tumors revealed similar pathways necessary for promoting metastasis in basal-like tumors with reduced signaling or expression of the IGF-1R. Functional analyses revealed the basis for the enhanced metastatic phenotype including alterations in E- and P-cadherins.