Correction: Cell, Isoform, and Environment Factors Shape Gradients and Modulate Chemotaxis.

[This corrects the article DOI: 10.1371/journal.pone.

Imaging Sensitivity of Quiescent Cancer Cells to Metabolic Perturbations in Bone Marrow Spheroids.

Malignant cells from breast cancer and other common cancers such as prostate and melanoma may persist in bone marrow as quiescent, non-dividing cells that remain viable for years or even decades before resuming proliferation to cause recurrent disease. This phenomenon, referred to clinically as tumor dormancy, poses tremendous challenges to curing patients with breast cancer. Quiescent tumor cells resist chemotherapy drugs that predominantly target proliferating cells, limiting success of neo-adjuvant and adjuvant therapies.

Modeling selective elimination of quiescent cancer cells from bone marrow.

Patients with many types of malignancy commonly harbor quiescent disseminated tumor cells in bone marrow. These cells frequently resist chemotherapy and may persist for years before proliferating as recurrent metastases. To test for compounds that eliminate quiescent cancer cells, we established a new 384-well 3D spheroid model in which small numbers of cancer cells reversibly arrest in G1/G0 phase of the cell cycle when cultured with bone marrow stromal cells.

Cell, isoform, and environment factors shape gradients and modulate chemotaxis.

Chemokine gradient formation requires multiple processes that include ligand secretion and diffusion, receptor binding and internalization, and immobilization of ligand to surfaces. To understand how these events dynamically shape gradients and influence ensuing cell chemotaxis, we built a multi-scale hybrid agent-based model linking gradient formation, cell responses, and receptor-level information. The CXCL12/CXCR4/CXCR7 signaling axis is highly implicated in metastasis of many cancers.

Microscale 3D collagen cell culture assays in conventional flat-bottom 384-well plates.

Three-dimensional (3D) culture systems such as cell-laden hydrogels are superior to standard two-dimensional (2D) monolayer cultures for many drug-screening applications. However, their adoption into high-throughput screening (HTS) has been lagging, in part because of the difficulty of incorporating these culture formats into existing robotic liquid handling and imaging infrastructures. Dispensing cell-laden prepolymer solutions into 2D well plates is a potential solution but typically requires large volumes of reagents to avoid evaporation during polymerization, which (1) increases costs, (2) makes drug penetration variable and (3) complicates imaging.

Surface-templated hydrogel patterns prompt matrix-dependent migration of breast cancer cells towards chemokine-secreting cells.

This paper describes a novel technique for fabricating spatially defined cell-laden collagen hydrogels, using patterned, non-adhesive polyacrylamide-coated polydimethylsiloxane (PDMS) surfaces as a template. Precisely patterned embedded co-cultures of breast cancer cells and chemokine-producing cells generated with this technique revealed matrix-dependent and chemokine isoform-dependent migration of cancer cells. CXCL12 chemokine-secreting cells induce significantly more chemotaxis of cancer cells when the 3-D extracellular matrix (ECM) includes components that bind the secreted CXCL12 chemokines.

Transfer, imaging, and analysis plate for facile handling of 384 hanging drop 3D tissue spheroids.

Three-dimensional culture systems bridge the experimental gap between in vivo and in vitro physiology. However, nonstandardized formation and limited downstream adaptability of 3D cultures have hindered mainstream adoption of these systems for biological applications, especially for low- and moderate-throughput assays commonly used in biomedical research. Here we build on our recent development of a 384-well hanging drop plate for spheroid culture to design a complementary spheroid transfer and imaging (TRIM) plate.

Transwells with microstamped membranes produce micropatterned two-dimensional and three-dimensional co-cultures.

This article describes a simple and rapid cell patterning method to form co-culture microarrays in commercially available Transwells. A thin poly(dimethylsiloxane) (PDMS) layer is printed on the underside of a Transwell using a PDMS stamp. Arbitrary cellular patterns are generated according to the geometric features of the thin PDMS layer through hydrodynamic forces that guide cells onto the membrane only over the PDMS-uncoated regions.

Microfluidic endothelium for studying the intravascular adhesion of metastatic breast cancer cells.

Background: The ability to properly model intravascular steps in metastasis is essential in identifying key physical, cellular, and molecular determinants that can be targeted therapeutically to prevent metastatic disease. Research on the vascular microenvironment has been hindered by challenges in studying this compartment in metastasis under conditions that reproduce in vivo physiology while allowing facile experimental manipulation.

Methodology/principal Findings: We present a microfluidic vasculature system to model interactions between circulating breast cancer cells with microvascular endothelium at potential sites of metastasis.