Olayioye, M. | bioRxiv Science

bioRxiv2026

DLC1 loss drives multicellular streaming invasion by enforcing spatially coordinated Rho and β1 integrin signaling

Efficient cancer cell invasion requires coordinated control of actomyosin contractility, extracellular matrix (ECM) engagement and remodeling, yet how these processes are integrated in complex, three-dimensional (3D) environments remains unclear. Here, we identify the tumor suppressor and RhoGAP protein DLC1 as molecular brake on multicellular streaming invasion in collagen-rich ECM. Using CRISPRoff-engineered breast cancer spheroids, DLC1 reconstitution models and patient-derived organoids embedded in collagen gels, we show that DLC1 downregulation promotes an efficient multicellular streaming phenotype. This invasion program requires matrix metalloproteinase activity, {beta}1 integrin engagement and Rho-ROCK-dependent actomyosin contractility. Mechanistically, DLC1 downregulation stabilized the rear-polarization of RhoA activity and increased {beta}1 integrin abundance, plasma membrane localization and activation. Separation-of-function mutants revealed that DLC1 restrains invasion through a dual mechanism: its RhoGAP activity limited actomyosin-driven streaming, whereas its LD-like talin-binding motif controlled {beta}1 integrin enrichment at the plasma membrane. Together, our findings provide a molecular basis for the prominent role of DLC1 as a metastasis suppressor.

Cancer Biology↗

bioRxiv2026

Reconstituting organotypic 2D microtissue co-cultures via sequential stenciling

In mammalian organisms, native tissue function depends on precise spatial organization down to the cellular level. Reconstituting tissue architectures in 2D in vitro platforms can provide a means to study direct and indirect cell-cell interactions in a variety of tissue contexts while remaining compatible with high-throughput assays and high-resolution live imaging. We combine cost-effective stereolithography leveraging 3D printing with replica molding to stencil spatially defined, multicellular culture systems with sub-millimeter resolution onto planar substrates. The system is designed for ease of use, requires no complex fabrication setups and scales readily to 96-well plates. Sequential stencil application and removal under a biosafety cabinet enables controlled positioning of multiple cell types and supported the maturation of tissue assemblies. We demonstrate the utility of this stencil-based patterning strategy in three applications. First, we employ a combination of two circular stencils to recreate a structural feature characteristic for the tumor microenvironment of solid tumors: the encapsulation of colorectal cancer cells by cancer-associated fibroblasts. Resulting cell patternings reproduce native tissue dynamics of the densely packed tumor tissues, in which cancer-associated fibroblast cells actively compress the cancer cells and confer targeted therapy resistance. Second, we probe the synthetic, diffusible morphogen system synNotch in patterned cell patches, where GFP-releasing cells generate a ligand-dependent gradient. Third, we recapitulate the characteristic crypt-villus architecture of the mammalian intestine by patterning intestinal organoids within a stencil-restricted crypt region and allowing differentiating cells to collectively migrate along a designed villus axis. The presented strategy allows for rebuilding multicellular tissue architectures in vitro with biologically relevant spatial precision for high-throughput drug screenings and dissection of tissue-specific cellular interactions.

bioengineering↗