Abstract 6024: An integrin αvβ3+ stem-like tumor cell subset promotes breast cancer progression via c-Jun/AXL signaling

Breast cancer cells bearing similarities to normal mammary stem cells play a key role in tumor progression. Here, we characterize a unique stem-like tumor cell population that expresses the integrin αvβ3 and is associated with aggressive patient disease. We now show that αvβ3+ cells that also express EpCAMLow represent a functionally and transcriptomically distinct breast cancer cell type. Rare αvβ3+ cells enrich for stemness properties such as anchorage-independent colony formation, self-renewal, differentiation and tumor initiation at limiting dilution. Unbiased whole transcriptome analysis by RNA-Seq identified several genes specifically upregulated in αvβ3+ cells that are also enriched in normal adult mammary stem cells. Phospho-array profiling of major signaling pathways revealed increased activation of the proto-oncogene c-Jun in αvβ3+ stem-like cells. Inhibition of JNK/c-Jun signaling further identified the receptor tyrosine kinase AXL as a critical downstream target gene necessary for tumorsphere formation. Our findings reveal a c-Jun/AXL signaling pathway required for stemness properties in αvβ3+ tumor cells important for breast cancer progression. Citation Format: Qi Sun, Yufen Wang, Adam Officer, Olivier Harismendy, Jay S. Desgrosellier. An integrin αvβ3+ stem-like tumor cell subset promotes breast cancer progression via c-Jun/AXL signaling [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6024.