Colin Zhang

Identification of ADAM10 as a major source of HER2 ectodomain sheddase activity in HER2 overexpressing breast cancer cells

ALL AUTHORS: Phillip C.C. Liu, Xiangdong Liu, Yanlong Li, Maryanne Covington, Richard Wynn, Reid Huber, Milton Hillman, Gengjie Yang, Dawn Ellis, Cindy Marando, Kamna Katiyar, Jodi Bradley, Kenneth Abremski, Mark Stow, Mark Rupar, Jincong Zhuo, Yun-Long Li, Qiyan Lin, David Burns, Meizhong Xu, Colin Zhang, Ding-Quan Qian, Chunhong He, Vaqar Sharief, Lingkai Weng, Costas Agrios, Eric Shi, Brian Metcalf, Robert Newton, Steven Friedman, Wenqing Yaol, Peggy Scherlel, Gregory Hollis, Timothy C. Burn Overexpression and activating mutations of ErbB family members have been implicated in the development and progression of a variety of tumor types. Cleavage of the HER2 receptor by an as yet unidentified ectodomain sheddase has been shown to liberate the HER2 extracellular domain (ECD) leaving a fragment with constitutive kinase activity that can provide ligand-independent growth and survival signals to the cell. This process is clinically relevant since HER2 ECD serum levels in metastatic breast cancer patients are associated with a poorer prognosis. Thus, inhibition of the HER2 sheddase may provide a novel therapeutic approach for breast cancer. We describe the use of transcriptional profiling, pharmacological and in vitro approaches to identify the major source of HER2 sheddase activity. Real-time PCR was used to identify those ADAM family members which were expressed in HER2 shedding cell lines. siRNAs that selectively inhibited ADAM10 expression reduced HER2 shedding. In addition, we profiled over 1000 small molecules for in vitro inhibition of a panel of ADAM and MMP proteins; a positive correlation was observed only between ADAM10 inhibition and reduction of HER2 ECD shedding in a cell based assay. Finally, in vitro studies demonstrate that in combination with low doses of Herceptin, selective ADAM10 inhibitors decrease proliferation in HER2 overexpressing cell lines while inhibitors, that do not inhibit ADAM10, have no impact. These results are consistent with ADAM10 being a major determinant of HER2 shedding, the inhibition of which, may provide a novel therapeutic approach for treating a variety of cancers with active HER2 signaling.

Abstract 771: Preclinical characterization of the selective FGFR inhibitor INCB054828

Aberrant signaling through Fibroblast Growth Factor Receptors (FGFR) has been reported in multiple types of human cancers. Genomic analyses of squamous cell lung, gastric and urothelial tumors have revealed recurrent genetic alterations in FGFR1, FGFR2 and FGFR3 genes, respectively. FGFR proteins contribute to the development of malignancies by promoting tumor cell proliferation, survival, and migration and supporting angiogenesis. Therefore targeting FGFR kinases may provide therapeutic benefit to patients with cancers that have genetic alterations in genes encoding components of the FGF-FGFR axis. INCB054828 is a potent inhibitor of FGFR1, FGFR2, and FGFR3 that has selective pharmacological activity against cancer cells with FGFR alterations. In vitro, INCB054828 potently inhibited the kinase activity of recombinant FGFR1, FGFR2 and FGFR3 enzymes and was highly selective against a panel of kinases including VEGFR2. In cellular assays, INCB054828 inhibited the autophosphorylation of FGFR proteins with low nanomolar IC 50 values and blocked signal transduction by FGFR to downstream markers of pathway activation. Cancer cell lines that have genetic alterations in FGFR1, FGFR2 and FGFR3 were uniquely sensitive to growth inhibition by INCB054828, with IC 50 values generally in the range of 3-50 nM, compared with cancer cell lines or normal cells without FGFR dependence (IC 50 > 1500 nM). In vivo, once-daily oral administration of INCB054828 inhibited the growth of tumors that are dependent upon FGFR1, FGFR2 and FGFR3 activity at tolerated doses. Suppression of tumor growth was dose-dependent and correlated with pharmacodynamic inhibition of FGFR. Collectively, these preclinical studies demonstrate that INCB054828 potently and selectively inhibits models of FGFR-dependent cancers in vitro and in vivo, supporting the compound9s clinical evaluation in patients harboring oncogenic FGFR activation. Citation Format: Phillip CC Liu, Liangxing Wu, Holly Koblish, Kevin Bowman, Yue Zhang, Ronald Klabe, Lynn Leffet, Darlise DiMatteo, Mark Rupar, Karen Gallagher, Michael Hansbury, Colin Zhang, Chunhong He, Paul Collier, Maryanne Covington, Richard Wynn, Swamy Yeleswaram, Kris Vaddi, Timothy Burn, Wenqing Yao, Reid Huber, Peggy Scherle, Gregory Hollis. Preclinical characterization of the selective FGFR inhibitor INCB054828. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 771. doi:10.1158/1538-7445.AM2015-771