Tumor invasion and metastasis is responsible for 90% of all deaths in cancer patients that are non-responsive to surgical procedures or initial therapeutic treatments. Clinical studies of inhibitors targeted against specific signalling pathways associated with tumor invasion frequently fail due to alternate signalling pathways that support persistent invasion through compensatory mechanisms. The aim of this study was to apply an image-based multi-well 3-dimensional (3D) invasion assay platform (OrisTM Pro Cell Invasion Assay, Platypus Technologies LLC) incorporating distinct cancer cell types and extra cellular matrix (ECM) substrates in parallel with an ultra-sensitive and high-throughput reverse phase protein microarray (RPPMA) platform (Zeptosens) to identify and validate drugs and their combinations targeting distinct modes of tumor invasion. At sub-micromolar concentrations the results show that a matrix metalloproteinase inhibitor (GM6001) and panel of tyrosine kinase inhibitors suppress the 3D invasion of two breast cancer cell lines (MDA-MB-231 and HCC1569) into a basement membrane matrix. The image based invasion assays further revealed an altered invasive morphology in response to distinct compound treatments, with cells losing their typical elongated mesenchymal phenotype and adopting a more ameoboid shape. These results suggest that inhibitor treatment initiates alternative invasive mechanisms. An RPPMA platform has been used to identify post-translational signalling pathways that drive adaptive responses to monotherapy and to guide selection of drug combination partners. Further testing of drug combinations in the OrisTM 3D invasion assay format shall enable quantification of additive and synergistic drug combination responses upon tumor invasion in parallel with cell viability endpoints. These studies provide a robust model by which to evaluate different combinations of drugs targeting tumor invasion that will help prioritize clinical development strategies. ACKNOWLEDGEMENT: This work was partially supported by NIH Grant 2R44GM090386 to Platypus Technologies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4303. doi:1538-7445.AM2012-4303