Receptor tyrosine kinase (RTK) amplification or inappropriate activation of one or more components of the RTK signaling pathway occur in many aggressive, treatment resistant tumors including triple negative breast cancer, and lung and pancreatic cancers. The clinical importance of RTK signaling has motivated the development of targeted therapies designed to block receptor activation and downstream signal transmission. RTK inhibitors can have dramatic short-term benefits, however patients frequently present with recurrent, RTK inhibitor resistant tumors. Our goal is to understand the fundamental origins of this therapeutic failure. Treatment resistance can arise due to cell-to-cell genetic or epigenetic RTK signaling heterogeneity. The extracellular matrix (ECM) tumor microenvironment is physically and biochemically heterogeneous and we and others find that the spatial-mechanical features of the ECM exert profound effects on RTK signaling. It is our thesis that in addition to genetic variation, external spatial-mechanical factors from the ECM are a critical cause of RTK therapy resistance. We predict that ECM environmental niches may protect some cancer cells from RTK inhibitor treatments, thus favoring the survival of tumor clones and enhancing the probability of these malignant cells developing `beneficial' mutations that increase their aggression and ultimately compromise patient survival. Yet, the molecular mechanisms whereby spatial-mechanical cues from the ECM regulate RTK signaling remain unclear. The Groves lab has developed robust supported lipid membrane platforms to study dynamics of proteins in signaling assemblies, both in reconstitution and in hybrid junctions with living cells. Using these systems Groves and colleagues demonstrated that the spatial organization of RTKs and their effectors at the plasma membrane modulate signal transduction initiation. The Weaver group has an arsenal of 2- and 3-dimensional organotypic culture systems and a suite of novel transgenic mouse models in which ECM mechanics and topography and the glycocalyx can be controlled, enabling precision studies in culture and in vivo. Weaver showed that ECM mechanics and topography and a hypoxia induced bulky glycocalyx alter RTK signaling; likely by altering membrane geometry and RTK effector activity. Here Groves and Weaver combine their expertise to test specific molecular mechanisms by which spatial-mechanical cues from the ECM alter RTK signaling. They will focus on Ras; a GTPase as a key RTK signaling node and interrogate the impact of physical modulations on Ras activation in their lipid bilayer, cellular, and in vivo platforms. These studies will reveal te molecular mechanisms by which the cellular microenvironment modulates RTK signaling and contributes to treatment resistance. From this understanding, the molecular mechanisms of coupling themselves will emerge as new targets to reduce incidence of RTK inhibitor resistance in cancer patients.

Public Health Relevance

Receptor tyrosine kinase (RTK) somatic mutations and over-expression characterize aggressive tumors of the breast, lung, and pancreas. Despite initial good response rates, tumors in patients treated with RTK inhibitors recur. Using physical and biochemical approaches and a suite of unique transgenic mouse models, this work will reveal the distinctively physical molecular mechanisms by which cellular microenvironment modulates RTK signaling and promotes RTK inhibitor resistance; these insights point the way to ultimately reduce acquired resistance to RTK inhibitor therapy, and increase the survival rate of cancer patients.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project--Cooperative Agreements (U01)
Project #
Application #
Study Section
Special Emphasis Panel (ZCA1)
Program Officer
Espey, Michael G
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California Berkeley
Schools of Arts and Sciences
United States
Zip Code
Sibener, Leah V; Fernandes, Ricardo A; Kolawole, Elizabeth M et al. (2018) Isolation of a Structural Mechanism for Uncoupling T Cell Receptor Signaling from Peptide-MHC Binding. Cell 174:672-687.e27
Tharp, Kevin M; Weaver, Valerie M (2018) Modeling Tissue Polarity in Context. J Mol Biol 430:3613-3628
Rauen, Katherine A; Schoyer, Lisa; Schill, Lisa et al. (2018) Proceedings of the fifth international RASopathies symposium: When development and cancer intersect. Am J Med Genet A 176:2924-2929
Chen, Zhongwen; Oh, Dongmyung; Biswas, Kabir H et al. (2018) Spatially modulated ephrinA1:EphA2 signaling increases local contractility and global focal adhesion dynamics to promote cell motility. Proc Natl Acad Sci U S A 115:E5696-E5705
Dong, Meimei; Spelke, Dawn P; Lee, Young Kwang et al. (2018) Spatiomechanical Modulation of EphB4-Ephrin-B2 Signaling in Neural Stem Cell Differentiation. Biophys J 115:865-873
Chung, Jean K; Lee, Young Kwang; Denson, John-Paul et al. (2018) K-Ras4B Remains Monomeric on Membranes over a Wide Range of Surface Densities and Lipid Compositions. Biophys J 114:137-145
Northcott, Josette M; Dean, Ivory S; Mouw, Janna K et al. (2018) Feeling Stress: The Mechanics of Cancer Progression and Aggression. Front Cell Dev Biol 6:17
Samson, Susan; Northey, Jason J; Plaks, Vicki et al. (2018) New Horizons in Advocacy Engaged Physical Sciences and Oncology Research. Trends Cancer 4:260-264
Ramakrishnan, N; Sreeja, K K; Roychoudhury, Arpita et al. (2018) Excess area dependent scaling behavior of nano-sized membrane tethers. Phys Biol 15:026002
Weaver, Valerie Marie (2017) Cell and tissue mechanics: the new cell biology frontier. Mol Biol Cell 28:1815-1818

Showing the most recent 10 out of 33 publications