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Skeletal metastasis is common in patients with advanced breast cancer and often caused by immune evasion of disseminated tumor cells (DTCs). In the skeleton, tumor cells not only disseminate to the bone marrow but also to osteogenic niches in which they interact with newly mineralizing bone extracellular matrix (ECM). However, it remains unclear how mineralization of collagen type I, the primary component of bone ECM, regulates tumor-immune cell interactions. Here, a combination of synthetic bone matrix models with controlled mineral content, nanoscale optical imaging, and flow cytometry are utilized to evaluate how collagen type I mineralization affects the biochemical and biophysical properties of the tumor cell glycocalyx, a dense layer of glycosylated proteins and lipids decorating their cell surface. These results suggest that collagen mineralization upregulates mucin-type O-glycosylation and sialylation by tumor cells, which increases their glycocalyx thickness while enhancing resistance to attack by natural killer (NK) cells. These changes are functionally linked as treatment with a sialylation inhibitor decreased mineralization-dependent glycocalyx thickness and made tumor cells more susceptible to NK cell attack. Together, these results suggest that interference with glycocalyx sialylation may represent a therapeutic strategy to enhance cancer immunotherapies targeting bone-metastatic breast cancer., (© 2024 Wiley‐VCH GmbH.)

Engrailed-1 (EN1) is a critical homeodomain transcription factor (TF) required for neuronal survival, and EN1 expression has been shown to promote aggressive forms of triple negative breast cancer. Here, it is reported that EN1 is aberrantly expressed in a subset of pancreatic ductal adenocarcinoma (PDA) patients with poor outcomes. EN1 predominantly repressed its target genes through direct binding to gene enhancers and promoters, implicating roles in the activation of MAPK pathways and the acquisition of mesenchymal cell properties. Gain- and loss-of-function experiments demonstrated that EN1 promoted PDA transformation and metastasis in vitro and in vivo. The findings nominate the targeting of EN1 and downstream pathways in aggressive PDA., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Macromolecularly crowded coacervate is useful in protein delivery for tissue engineering and regenerative medicine. However, coacervate tends to aggregate easily, which impedes their application. Here, this work presents a method to prepare coacervate with enhanced stability. This work assembles phospholipids on the surface of a coacervate to form lipocoacervate (LipCo). The resultant LipCo possesses a discrete spherical structure with a coacervate interior and phospholipid outer shell. The size of LipCo does not change over the four-week observation window, whereas coacervate coalesced into one bulk phase within 30 min. This work uses vascular endothelial growth factor-C (VEGF-C) and fibroblast growth factor-2 (FGF-2) as examples to test LipCo's ability to maintain protein bioactivity. The in vitro lymphangiogenesis assay demonstrates that human dermal lymphatic endothelial cells (LECs) formed increased network of cord in VEGF-C and FGF-2 loaded LipCo group compared to free proteins and proteins loaded in coacervate. Overall, LipCo could serve as a protein delivery vehicle with improved colloidal stability., (© 2023 Wiley-VCH GmbH.)

Metastasis is the leading cause of breast cancer-related deaths and is often driven by invasion and cancer-stem like cells (CSCs). Both the CSC phenotype and invasion are associated with increased hyaluronic acid (HA) production. How these independent observations are connected, and which role metabolism plays in this process, remains unclear due to the lack of convergent approaches integrating engineered model systems, computational tools, and cancer biology. Using microfluidic invasion models, metabolomics, computational flux balance analysis, and bioinformatic analysis of patient data, the functional links between the stem-like, invasive, and metabolic phenotype of breast cancer cells as a function of HA biosynthesis are investigated. These results suggest that CSCs are more invasive than non-CSCs and that broad metabolic changes caused by overproduction of HA play a role in this process. Accordingly, overexpression of hyaluronic acid synthases (HAS) 2 or 3 induces a metabolic phenotype that promotes cancer cell stemness and invasion in vitro and upregulates a transcriptomic signature predictive of increased invasion and worse patient survival. This study suggests that HA overproduction leads to metabolic adaptations to satisfy the energy demands for 3D invasion of breast CSCs highlighting the importance of engineered model systems and multidisciplinary approaches in cancer research., (© 2022 Wiley-VCH GmbH.)

Dielectrophoresis is a robust approach for the manipulation and separation of (bio)particles using microfluidic platforms. We developed a dielectrophoretic corral trap in a microfluidic device that utilizes negative dielectrophoresis to capture single spherical polystyrene particles. Circular-shaped micron-size traps were employed inside the device and the three-dimensional trap stiffness (restoring trapping force from equilibrium trapping location) was analyzed using 4.42 μm particles and 1 MHz of an alternating electric field from 6 V P-P to 10 V P-P . The trap stiffness increased exponentially in the x- and y-direction, and linearly in the z-direction. Image analysis of the trapped particle movements revealed that the trap stiffness is increased 608.4, 539.3, and 79.7% by increasing the voltage from 6 V P-P to 10 V P-P in the x-, y-, and z-direction, respectively. The trap stiffness calculated from a finite element simulation of the device confirmed the experimental results. This analysis provides important insights to predict the trapping location, strength of the trapping, and optimum geometry for single particle trapping and its applications such as single-molecule analysis and drug discovery., (© 2020 Wiley-VCH GmbH.)

Poly(glycerol-sebacate) (PGS) is a biodegradable elastomer known for its mechanical properties and biocompatibility for soft tissue engineering. However, harsh thermal crosslinking conditions are needed to make PGS devices. To facilitate the thermal crosslinking, citric acid is explored as a crosslinker to form poly(glycerol sebacate citrate) (PGSC) elastomers. The effects of varying citrate contents and curing times are investigated on the mechanical properties, elasticity, degradation, and hydrophilicity. To examine the potential presence of unreacted citric acid, material acidity is monitored in relation to the citrate content and curing times. It is discovered that a low citrate content and a short curing time produce PGSC with tunable mechanical characteristics similar to PGS with enhanced elasticity. The materials demonstrate good cytocompatibility with human umbilical vein endothelial cells similar to the PGS control. The research study suggests that PGSC is a potential candidate for large-scale biomedical applications because of the quick thermal crosslink and tunable elastomeric properties., (© 2020 Wiley-VCH GmbH.)

Vasculopathy and the consequential ischemia are major medical challenges. Grafting is an effective treatment to vascular occlusion. However, autologous grafting, despite scarcity, is the only choice for small diameter blood vessels. Synthetic grafts can fill the gap if they can work satisfactorily in arterial circulation. Electrospun polycaprolactone (PCL) sheathed porous poly(glycerol sebacate) (PGS) vascular grafts have good performances in arterial circulation in abdominal aortas and carotid arteries in rats. However, a major issue associated with the graft remodeling in vivo is limited neo-tissue formation inside PCL sheaths. Small pores of PCL sheaths inhibit cell infiltration and migration. To increase porosity of PCL sheaths of PGS-PCL composite grafts, diameters of electrospun PCL fibers are increased. The thick PCL fibers encourage cell migration and elicit a higher degree of CD206 + cells. In addition, some of the CD206 + cells co-express vascular cell markers in the thick-fiber grafts. The thick-fiber grafts also show improved mechanical properties and a higher elastin and collagen content. The data demonstrate the feasibility of improving graft vascular remodeling by increasing PCL fiber diameters and the critical role of CD206 + cells during graft vascular remodeling., (© 2020 Wiley-VCH GmbH.)

Obesity increases the risk and worsens the prognosis for breast cancer due, in part, to altered adipose stromal cell (ASC) behavior. Whether ASCs from obese individuals increase migration of breast cancer cells relative to their lean counterparts, however, remains unclear. To test this connection, multicellular spheroids composed of MCF10A-derived tumor cell lines of varying malignant potential and lean or obese ASCs were embedded into collagen scaffolds mimicking the elastic moduli of interstitial breast adipose tissue. Confocal image analysis suggests that tumor cells alone migrate insignificantly under these conditions. However, direct cell-cell contact with either lean or obese ASCs enables them to migrate collectively, whereby obese ASCs activate tumor cell migration more effectively than their lean counterparts. Time-resolved optical coherence tomography (OCT) imaging suggests that obese ASCs facilitate tumor cell migration by mediating contraction of local collagen fibers. Matrix metalloproteinase (MMP)-dependent proteolytic activity significantly contributes to ASC-mediated tumor cell invasion and collagen deformation. However, ASC contractility is also important, as co-inhibition of both MMPs and contractility is necessary to completely abrogate ASC-mediated tumor cell migration. These findings imply that obesity-mediated changes of ASC phenotype may impact tumor cell migration and invasion with potential implications for breast cancer malignancy in obese patients.

Antibiotic-resistant bacteria are a major global health threat that continues to rise due to a lack of effective vaccines. Of concern are Klebsiella pneumoniae that fail to induce in vivo germinal center B cell responses, which facilitate antibody production to fight infection. Immunotherapies using antibodies targeting antibiotic-resistant bacteria are emerging as promising alternatives, however, they cannot be efficiently derived ex vivo , necessitating the need for immune technologies to develop therapeutics. Here, PEG-based immune organoids were developed to elucidate the effects of polymer end-point chemistry, integrin ligands, and mode of K. pneumoniae antigen presentation on germinal center-like B cell phenotype and epigenetics, to better define the lymph node microenvironment factors regulating ex vivo germinal center dynamics. Notably, PEG vinyl sulfone or acrylate failed to sustain primary immune cells, but functionalization with maleimide (PEG-4MAL) led to B cell expansion and germinal center-like induction. RNA sequencing analysis of lymph node stromal and germinal center B cells showed niche associated heterogeneity of integrin-related genes. Incorporation of niche-mimicking peptides revealed that collagen-1 promoted germinal center-like dynamics and epigenetics. PEG-4MAL organoids elucidated the impact of K. pneumoniae outer membrane-embedded protein antigen versus soluble antigen presentation on germinal centers and preserved the response across young and aged mice., Competing Interests: Competing interests: The authors declare that they have no competing interests.

Mechanical properties and degradation profile are important parameters for the applications of biodegradable polyester such as poly(glycerol sebacate) in biomedical engineering. Here, a strategy is reported to make palmitate functionalized poly(glycerol sebacate) (PPGS) to alter the polymer hydrophobicity, crystallinity, microstructures and thermal properties. The changes of these intrinsic properties impart tunable degradation profiles and mechanical properties to the resultant elastomers depending on the palmitate contents. When the palmitates reach up to 16 mol%, the elastic modulus is tuned from initially 838 ± 55 kPa for the PGS to 333 ± 21 kPa for the PPGS under the same crosslinking conditions. The elastomer undergoes reversible elastic deformations for at least 1000 cycles within 20% strain without failure and shows enhanced elasticity. The polymer degradation is simultaneously inhibited because of the increased hydrophobicity. This strategy is different with other PGS modifications which could form a softer elastomer with less crosslinks but typically lead to a quicker degradation. Because the materials are made from endogenous molecules, they possess good cytocompatibility similar to the PGS control. Although these materials are designed specifically for small arteries, it is expected that they will be useful for other soft tissues too., (© 2020 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

Cell contractility regulates multiple cell behaviors which contribute to both normal and pathological processes. However, measuring cell contractility remains a technical challenge in complex biological samples. The current state of the art technologies employed to measure cell contractility have inherent limitations that greatly limit the experimental conditions under which they can be used. Here, we use quantitative polarization microscopy to extract information about cell contractility. We show that the optical retardance signal measured from the cell body is proportional to cell contractility in 2-dimensional and 3-dimensional platforms, and as such can be used as a straightforward, tractable methodology to assess cell contractility in a variety of systems. This label-free optical method provides a novel and flexible way to assess cellular forces of single cells and monolayers in several cell types, fixed or live, in addition to cells present in situ in mouse tumor tissue samples. This easily implementable and experimentally versatile method will significantly contribute to the cell mechanics field., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Traditional cell culture and animal models utilized for preclinical drug screening have led to high attrition rates of drug candidates in clinical trials due to their low predictive power for human response. Alternative models using human cells to build in vitro biomimetics of the human body with physiologically relevant organ-organ interactions hold great potential to act as "human surrogates" and provide more accurate prediction of drug effects in humans. This review is a comprehensive investigation into the development of tissue-engineered human cell-based microscale multiorgan models, or multiorgan microphysiological systems for drug testing. The evolution from traditional models to macro- and microscale multiorgan systems is discussed in regards to the rationale for recent global efforts in multiorgan microphysiological systems. Current advances in integrating cell culture and on-chip analytical technologies, as well as proof-of-concept applications for these multiorgan microsystems are discussed. Major challenges for the field, such as reproducibility and physiological relevance, are discussed with comparisons of the strengths and weaknesses of various systems to solve these challenges. Conclusions focus on the current development stage of multiorgan microphysiological systems and new trends in the field., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)