Pharmacological activation of myosin II paralogs to correct cell mechanics defects

Abstract

Current approaches to cancer treatment focus on targeting signal transduction pathways. Here, we develop an alternative system for targeting cell mechanics for the discovery of novel therapeutics. We designed a live-cell, high-throughput chemical screen to identify mechanical modulators. We characterized 4-hydroxyacetophenone (4-HAP), which enhances the cortical localization of the mechanoenzyme myosin II, independent of myosin heavy-chain phosphorylation, thus increasing cellular cortical tension. To shift cell mechanics, 4-HAP requires myosin II, including its full power stroke, specifically activating human myosin IIB (MYH10) and human myosin IIC (MYH14), but not human myosin IIA (MYH9). We further demonstrated that invasive pancreatic cancer cells are more deformable than normal pancreatic ductal epithelial cells, a mechanical profile that was partially corrected with 4-HAP, which also decreased the invasion and migration of these cancer cells. Overall, 4-HAP modifies nonmuscle myosin II-based cell mechanics across phylogeny and disease states and provides proof of concept that cell mechanics offer a rich drug target space, allowing for possible corrective modulation of tumor cell behavior. mechanical modulator | 3,4-dichloroaniline | 4-hydroxyacetophenone | myosin II | pancreatic cancer C ell shape change processes include cell growth, division, motility, and the formation of complex structures like tissues and organs, all of which are governed by the intersection of biochemistry, genetics, and mechanics. These three modules are integral not just for normal function in healthy cells but also in disease states. Pharmacological manipulation of some of these modules has already led to treatment strategies for inflammation and cancer (e.g., paclitaxel) (1, 2). However, many presently available therapies, which address only one aspect of cell shape change, typically either fail to abolish the disease completely or lead to compensatory regulatory changes, and therefore to drug resistance. Targeting cell mechanics remains an underused approach for drug development. In cancer, altered cell mechanics are a hallmark of metastatic efficiency: cell stiffness decreases up to 70% in many metastatic cancer cells (3-5). It is rational then that one therapeutic approach is to increase cellular elasticity, which would, in turn, reduce metastatic potential and act downstream of cancer-inducing genetic alterations.Known mechanical modulators (e.g., latrunculin, blebbistatin) are often lethal, have numerous off-site targets, and act to generate a softer and metastatic-like mechanical phenotype (6, 7). However, the field's ability to increase cellular elasticity on acute time scales is highly restricted. In an effort to close this gap and find modulators that stiffen cells, we leveraged our molecular and analytical understanding of cytokinesis, an evolutionarily conserved and highly mechanical cell shape change event, to establish an in vivo, large-scale, high-throughput chemical screen for small-molecule modulators of cell shap...

Inertial Microfluidic Cell Stretcher (iMCS): Fully Automated, High‐Throughput, and Near Real‐Time Cell Mechanotyping

“…[1] Drugs that modify cytoskeletal or nuclear architecture are often applied in cancer treatment, [8, 36] and recently, 4-hydroxyacetophenone (4-HAP) was found to alter pancreatic cancer mechanical properties by stimulating myosin-II and enhancing its cortical localization, which reduces the invasion and migration of pancreatic cancer cells by stiffening them. [8] Micropipette aspiration was used for the study measuring the cell deformability to find the efficacy of 4-HAP; however, due to its low throughput, only tens of cells were characterized to verify the drug responses. Furthermore, it was suggested that 4-HAP can be applied to other cancers, though with a micropipette aspiration approach, it is limited to test other various cancer cell lines at different stages.…”

Fibroblasts Lead the Way: A Unified View of 3D Cell Motility

“…For example, the mechanical response of cells to their environment may be defective in some cancer cells [66]. Restoring this response may reduce the inappropriate movement of the cancer cells [67]. Studying the molecular mechanisms of cell movement in 3D extracellular matrix, rather than on 2D tissue culture plastic, is likely to provide the most efficient way to address these and other important questions (see Outstanding Questions Box) in the future.…”

Cellular adaptation to biomechanical stress across length scales in tissue homeostasis and disease

“…Furthermore, to treat diseases that include an element of defective mechanotransduction, putative compounds must be tested in the appropriate 3D matrix mechanics to accurately predict responses [116], and active efforts to develop compounds that selectively target key elements of the mechanotransduction pathway will be critical [117]. New mechanistic insights into how cells sense and respond to tissue mechanics will follow from the widespread implementation of in silico modeling [118] to develop complex cell-cell and cell-matrix models [92,97,106,119], and the development of 3D models to systematically tease apart the influence of diverse matrix mechanical properties, biomolecules, and genetic alterations on cell behaviors and fate in a controlled manner [120-123].…”