Differential modulation of cell morphology, migration, and Neuropilin-1 expression in cancer and non-cancer cell lines by substrate stiffness.

Physical changes in the tumor microenvironment, such as increased stiffness, regulate cancer hallmarks and play an essential role in gene expression, cell morphology, migration, and malignancy. However, the response of cancer cells to stiffness is not homogeneous and varies depending on the cell type and its mechanosensitivity. In this study, we investigated the differential responses of cervical (HeLa) and prostate (PC-3) cancer cell lines, as well as non-tumoral cell lines (HEK293 and HPrEC), to stiffness using polyacrylamide hydrogels mimicking normal and tumoral tissues. We analyzed cell morphology, migration, and the expression of neuropilin 1 (NRP1), a receptor involved in angiogenesis, cell migration, and extracellular matrix remodeling, known to be associated with cancer progression and poor prognosis. Our findings reveal that NRP1 expression increases on substrates mimicking the high stiffness characteristic of tumoral tissue in the non-tumoral cell lines HPrEC and HEK293. Conversely, in tumoral PC-3 cells, stiffness resembling normal prostate tissue induces an earlier and more sustained expression of NRP1. Furthermore, we observed that stiffness influences cell spreading, pseudopodia formation, and the mode of cell protrusion during migration. Soft substrates predominantly trigger bleb cell protrusion, while pseudopodia protrusions increase on substrates mimicking normal and tumor-like stiffnesses in HPrEC cells compared to PC-3 cells. Stiffer substrates also enhance the percentage of migratory cells, as well as their velocity and total displacement, in both non-tumoral and tumoral prostate cells. However, they only improve the persistence of migration in tumoral PC-3 cells. Moreover, we found that NRP1 co-localizes with actin, and its suppression impairs tumoral PC-3 spreading while decreasing pseudopodia protrusion mode. Our results suggest that the modulation of NRP1 expression by the stiffness can be a feedback loop to promote malignancy in non-tumoral and cancer cells, contingent upon the mechanosensitivity of the cells.

Mimicking Neural Stem Cell Niche by Biocompatible Substrates.

Neural stem cells (NSCs) participate in the maintenance, repair, and regeneration of the central nervous system. During development, the primary NSCs are distributed along the ventricular zone of the neural tube, while, in adults, NSCs are mainly restricted to the subependymal layer of the subventricular zone of the lateral ventricles and the subgranular zone of the dentate gyrus in the hippocampus. The circumscribed areas where the NSCs are located contain the secreted proteins and extracellular matrix components that conform their niche. The interplay among the niche elements and NSCs determines the balance between stemness and differentiation, quiescence, and proliferation. The understanding of niche characteristics and how they regulate NSCs activity is critical to building in vitro models that include the relevant components of the in vivo niche and to developing neuroregenerative approaches that consider the extracellular environment of NSCs. This review aims to examine both the current knowledge on neurogenic niche and how it is being used to develop biocompatible substrates for the in vitro and in vivo mimicking of extracellular NSCs conditions.

Growth hormone improves hippocampal adult cell survival and counteracts the inhibitory effect of prolonged sleep deprivation on cell proliferation.

Sleep deprivation (SD) produces numerous deleterious changes in brain cells, including apoptosis. It has been demonstrated that growth hormone (GH) stimulates cell growth and counteracts apoptosis, although this anti-apoptotic effect has not been tested against SD. To determine the protective effect of GH administration on cell proliferation and survival in the dentate gyrus (DG) of the hippocampus after sleep deprivation; we injected Wistar adult rats with a low dose of recombinant human GH (rhGH 5 ng/kg) per seven days and then we gently sleep deprived the animals for 48 consecutive hours. 5-Bromodeoxiuridine (BrdU) was administered to assess cell proliferation after the GH treatment and NeuN was used as marker of cell fate. Our results indicate that GH produced a three fold increase in the number of BrdU positive cells within the DG [Control = 1044 ± 106.38 cells, rhGH = 2952 ± 99.84 cells, P<0.01]. In contrast, 48 h of SD significantly reduced cell proliferation but this effect was antagonized by the GH administration [SD = 540 ± 18.3 cells, rhGH + SD = 1116 ± 84.48 cells, P<0.004]. Paradoxically, SD and GH administration increased cell survival separately but no significantly compared with control animals. However, cell survival was increased in animals treated with rhGH+SD compared to rats injected with saline solution [P<0.04]. Within the survival cells, the percentage of neurons was higher in SD animals [95%] compared with saline group, while this percentage (NeuN positive cells) was increased in animals treated with rhGH+SD [120%] compared with rhGH [25%] alone. Our findings indicate that GH strongly promotes cell proliferation in the adult brain and also protects the hippocampal neuronal precursors against the deleterious effect of prolonged sleep loss.

Adult cystatin C reference intervals determined by nephelometric immunoassay.

OBJECTIVE: The aim of this study was to determine the adult reference values for cystatin C (CysC) and to evaluate their consistence with those reported in the literature. DESIGN AND METHODS: CysC was analyzed in a consecutive series of subjects (100 males and 100 females) by a nephelometric immunoassay. Medline was searched for CysC reference values. RESULTS: CysC reference intervals showed 4-11% of variation at the upper limit. The mean upper limit was

A simple and sensitive assay for GH activity based on 3T3-F442A cell differentiation.

We describe a fast, sensitive, specific, and simple in vitro assay for GH biological activity, based on the differentiation of 3T3-F442A cells into adipocytes. The 3T3-F442A cells were directly plated at 1.5 x 10(4)cells/cm(2) in medium with or without various concentrations of human growth hormone (hGH). After 7 days, cells were lysed with buffer containing 0.5 % (v/v) Triton X-100, and adipose conversion was quantitated by the activity of the adipogenic enzyme glycerophosphate dehydrogenase. The assay is highly sensitive and specific for GH from different species. These culture conditions have shortened the time for the cells to undergo adipose differentiation, and they might also be useful to design and test drugs or agents that modify adipocyte differentiation or lipid metabolism, or for evaluation of cytotoxic and pharmacologic effects of drugs and other compounds.