Circulating tumor cells (CTCs) are the principal vehicle for the spread of non-hematologic cancer disease from a primary tumor, involving extravasation of CTCs across blood vessel walls, to form secondary tumors in remote organs. Herein, a polydimethylsiloxane-based microfluidic system is developed and characterized for in vitro systematic studies of organ-specific extravasation of CTCs. The system recapitulates the two major aspects of the in vivo extravasation microenvironment: local signaling chemokine gradients in a vessel with an endothelial monolayer. The parameters controlling the locally stable chemokine gradients, flow rate, and initial chemokine concentration are investigated experimentally and numerically. The microchannel surface treatment effect on the confluency and adhesion of the endothelial monolayer under applied shear flow has also been characterized experimentally. Further, the conditions for driving a suspension of CTCs through the microfluidic system are discussed while simultaneously maintaining both the local chemokine gradients and the confluent endothelial monolayer. Finally, the microfluidic system is utilized to demonstrate extravasation of MDA-MB-231 cancer cells in the presence of CXCL12 chemokine gradients. Consistent with the hypothesis of organ-specific extravasation, control experiments are presented to substantiate the observation that the MDA-MB-231 cell migration is attributed to chemotaxis rather than a random process.
The genus Epilobium consists of approximately 200 species that are distributed worldwide. Some of these herbs have been used for the treatment of diarrhea, infection, irritation, and other disorders associated with inflammation. Unlike that of other Epilobium species, there is little scientific understanding of the pharmacological effect of Epilobium amurense subsp. cephalostigma (Hausskn.) C. J. Chen, Hoch & P. H. Raven. In this study, we demonstrated the anti-inflammatory and antioxidative properties of an E. amurense 95% ethanol extract (EACEE) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, and observed the underlying mechanism of this effect. We measured the productions of nitric oxide (NO) and reactive oxygen species, and examined the actions of EACEE on transcription factors in the macrophages. EACEE reduced NO production and inducible nitric oxide synthase protein levels via the inhibition of the nuclear factor (NF)-κB pathway. Additionally, EACEE suppressed redundant reactive oxygen species production and regulated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling. Furthermore, EACEE significantly inhibited the phosphorylation of p38 mitogen-activated protein kinase (MAPK). Overall, these results indicate that EACEE exerts anti-inflammatory and antioxidant effects via the activation of Nrf2/HO-1 and inhibition of NF-κB/p38 MAPK signaling.
Obesity is associated with an increased risk of cardiovascular disease. Gambi-jung (GBJ), a modified herbal formula of Taeumjowi-tang, induces weight loss in high-fat diet (HFD)-fed obese mice. Meanwhile, concerns have been raised regarding
Abstract Heme b (iron protoporphyrin IX) plays important roles in biology as a metallocofactor and signaling molecule. However, the targets of heme signaling and the network of proteins that mediate the exchange of heme from sites of synthesis or uptake to heme dependent or regulated proteins are poorly understood. Herein, we describe a quantitative mass spectrometry-based chemoproteomics strategy to identify exchange labile hemoproteins in human embryonic kidney HEK293 cells that may be relevant to heme signaling and trafficking. The strategy involves depleting endogenous heme with the heme biosynthetic inhibitor succinylacetone (SA), leaving putative heme binding proteins in their apo- state, followed by the capture of those proteins using hemin-agarose resin and finally elution and identification by mass spectrometry. By identifying only those proteins that interact with high specificity to hemin-agarose relative to control beaded agarose in a SA-dependent manner, we have expanded the number of proteins and ontologies that may be involved in binding and buffering labile heme or are targets of heme signaling. Notably, these include proteins involved in chromatin remodeling, DNA damage response, RNA splicing, cytoskeletal organization and vesicular trafficking, many of which have been associated with heme through complimentary studies published recently. Taken together, these results provide support for the emerging role for heme in an expanded set of cellular processes from genome integrity to protein trafficking and beyond.
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