Nucleating amoeboid cancer cell motility with Diaphanous related formins.

The tissue invasive capacity of cancer cells is determined by their phenotypic plasticity. For instance, mesenchymal to amoeboid transition has been found to facilitate the passage of cancer cells through confined environments. This phenotypic transition is also heavily regulated by the architecture of the actin cytoskeleton, which may increase myosin contractility and the intracellular pressure that is known to drive bleb formation. In this review, we highlight several Diaphanous related formins (DRFs) that have been found to promote or suppress bleb formation in cancer cells, which is a hallmark of amoeboid migration. Based on the work discussed here, the role of the DRFs in cancer(s) is worthy of further scrutiny in animal models, as they may prove to be therapeutic targets.

The activation of INF2 by Piezo1/Ca2+ is required for mesenchymal to amoeboid transition in confined environments.

To invade heterogenous tissues, transformed cells may undergo a mesenchymal to amoeboid transition (MAT). However, the molecular mechanisms regulating this transition are poorly defined. In invasive melanoma cells, we demonstrate that intracellular [Ca2+] increases with the degree of confinement in a Piezo1 dependent fashion. Moreover, Piezo1/Ca2+ is found to drive amoeboid and not mesenchymal migration in confined environments. Consistent with a model in which Piezo1 senses tension at the plasma membrane, the percentage of cells using amoeboid migration is further increased in undulating microchannels. Surprisingly, amoeboid migration was not promoted by myosin light chain kinase (MLCK), which is sensitive to intracellular [Ca2+]. Instead, we report that Piezo1/Ca2+ activates inverted formin-2 (INF2) to induce widespread actin cytoskeletal remodeling. Strikingly, the activation of INF2 is found to promote de-adhesion, which in turn facilitates MAT. Using micropatterned surfaces, we demonstrate that cells require INF2 to effectively migrate in environments with challenging mechanochemical properties.

Ethanol affects fibroblast behavior differentially at low and high doses: A comprehensive, dose-response evaluation.

This study aims to develop a comprehensive understanding of effects of low and high doses of ethanol on cellular biochemistry and morphology. Here, fibroblast cells are exposed to ethanol of varied concentrations [0.005-10 % (v/v)] to investigate cellular activity, cytoskeletal organization, cellular stiffness, mitochondrial structure, and real-time behavior. Our results indicate a sharp difference in cellular behavior above and below 1 % ethanol concentration. A two-fold increase in MTT activity at low doses is observed, whereas at high doses it decreases. This increased activity at low doses does not involve cell proliferation changes or mitochondrial impairment, as seen at higher doses. Moreover, the study identifies different types of mitochondrial structure impairment at high doses. Morphologically, cells demonstrate a gradual change in cytoskeletal organization and an increase in cell stiffness with increase in doses. Cells exhibit adaptation to sub-toxic doses of ethanol, wherein recovery from ethanol-induced stress is a dose-dependent phenomenon. Cell survival at low doses and toxicity at higher doses are attributed to mild and strong oxidative stress, respectively. Overall, the study provides a comprehensive understanding of dose-dependent effects of ethanol, manifesting its biphasic or hormetic response, biochemically, at low doses and illustrating its toxicological effects at higher doses.

Three Dimensional Quercetin-Functionalized Patterned Scaffold: Development, Characterization, and In Vitro Assessment for Neural Tissue Engineering.

Regeneration of injured neuronal areas is a big challenge owing to the complex structure and function of the nervous system along with the limited regeneration capacity of neural cells. Recent reports show that patterned and functionalized scaffolds could control neural cell directional growth. In this study, aligned nanofibers (ANFs) were fabricated using a versatile and cost-effective approach, electrospinning, and further processed to make a patterned hybrid scaffold (HANF). The patterned scaffold had circular rings of ANFs reinforced in a biocompatible gellan-gelatin hydrogel matrix to provide adequate mechanical strength and contact guidance for adhesion and growth of neural cells in vitro. Quercetin was loaded into the nanofibrous scaffold to provide a functional agent that supported regeneration of neural cells. The reinforced ANFs enhanced the mechanical strength of the scaffold and provided a cylindrical nerve conduit structure to support neuronal cell growth. The influence of scaffold topology on cell behavior was assessed in in vitro cell culture conditions that revealed that the functionalized patterned scaffolds favored directed neurite cell growth/extension with favored cell culture morphology and showed no cytotoxicity toward neural cells. The results ultimately indicated that the fabricated scaffold has potential for guiding nerve tissue growth and can be used as nerve regeneration scaffolds.

Modelling and optimization of NaOH-etched 3-D printed PCL for enhanced cellular attachment and growth with minimal loss of mechanical strength.

Despite having gained success in achieving intricate geometries for bone-graft fabrication, 3D printing technology still lacks good implant-tissue bonding. This can be addressed with alkaline surface post-treatment of 3D printed grafts, which improves the surface morphology and cellular response (attachment and proliferation), as shown in this study of polycaprolactone (PCL). The parameters for process optimization were NaOH-concentration, reaction temperature, and treatment time. Along with the hydrolysis reaction, its morphological implications at micro-level was also studied here for the first time. The modified surface was characterized by measuring surface porosity, surface roughness, and cellular response. A kinetic model was developed to correlate surface porosity with concentration, temperature and time. The concept of treatment intensity is introduced, which is a lumped parameter consisting of the product of the three governing parameters, which shows a concentration-temperature-time equivalency. With the increase in treatment intensity, surface porosity increased to ~60%, the surface roughness (RMS value) increased to ~700 nm, and cellular response improved till surface porosity reaches ~35%. This study establishes the importance of NaOH-PCL interaction and proposes that the surface reaction mechanism studied here can be exploited to enhance the in-vivo performance of bone grafts.