Abstract P2-05-09: Functional mapping of the oncogenic kinome activity of triple-negative breast cancer cells

Background: Triple-negative breast cancer (TNBC) accounts for approximately 10 to 15% of all breast cancer cases. The management of TNBC cases will significantly improve once molecular mechanisms specific to TNBC cells will be identified and treated accordingly. Evidence suggests that TNBC cells display deregulated kinase-dependent signaling cascades that differ from non-triple-negative breast cancer cells. We hypothesized that uniquely divergent phospho-circuits could be distinguished between TNBC and non-TNBC cell lines. By revealing such unique, dysfunctional phospho-signaling network, our long-term objective is to identify kinases that underpin triple-negative breast cancer development, and can be inhibited using targeted therapy. Methods: The kinome activity of TNBC and non-TNBC cell lines was identified (HCC70, MDA-MB-231, MDA-MB-436 compared to AU565, MCF-7, T47D). The functional phospho-signature of each breast cancer cell was analyzed using a high throughput experimental platform that monitors the level of activity of myriad kinases at once. This technique uses 242 phospho-sensing probes and 78 controls in an aqueous-based assay to simultaneously and directly measure the phospho-catalytic activity of phosphorylating enzymes in cell lysates. We mapped the most significantly deranged phospho-signaling cascades and the related kinases. Results: Using 6 cell lines tested under various conditions, we generated 72 phospho-signatures, out of a total of 23,040 data points. After validating the repeatability and robustness of the assay, the kinase activity signature of each breast cancer cell line was analyzed and compared to each other using unsupervised hierarchical clustering. The phospho-sensing assay revealed the heterogeneity of kinase activity networks among breast cancer cells. These data also established that phospho-signaling cascades related to AKT, ERK, and SRC kinases were differentially altered in TNBC and non-TNBC cell lines. Conclusions: We successfully identified unique phospho-circuits of TNBC and non-TNBC cell lines. Our goal is now to test whether specific kinase inhibitors can efficiently kill or prevent the growth of TNBC cell lines in culture and animal models. We will expand our approach into a high-content, functional kinome-screening platform to characterize the phospho-fingerprint of breast cancer cells and tissues, and explore the druggable, kinase-dependent mechanisms critical to triple-negative breast tumors. Citation Format: Bo Pan, Miki Mori, Pei Rong Evelyn Lee, Marij Hartog, Qiang Sun, Laura van 9t Veer, Jean-Philippe Coppe. Functional mapping of the oncogenic kinome activity of triple-negative breast cancer cells [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-05-09.