Cancer Biology

Members of the claudin family of tight junction proteins regulate paracellular permeability and modulate cell signaling. During junction remodeling, these proteins are selectively inserted into or retrieved from the tight junctions, but the control and coordination of these processes remain incompletely understood. Visualization of claudins allows the assessment of changes in their localization and abundance. We use the described protocol to stain claudin-2, but it can also be adapted to stain any tight junction protein. We found that using methanol for fixing allows the best preservation of claudin-2 both at the membrane and in cytoplasmic vesicles. Staining is done using a claudin-2 specific primary and a fluorescently labelled secondary antibody, along with DAPI to label nuclei. The samples are then imaged using confocal microscopy, and a z-stack is obtained allowing visualization of both junctional and intracellular claudin-2. Total claudin-2 signal can be quantified after 3D reconstruction of the images using the Imaris software.

The vascular endothelium is essential to normal vascular homeostasis. Its dysfunction participates in various cardiovascular disorders. Murine endothelial cell culture is an important tool for cardiovascular disease research. This protocol demonstrates a quick, efficient method for the isolation of microvascular endothelial cells from murine tissues without any special equipment. To isolate endothelial cells, the lung or heart were mechanically minced and enzymatically digested with collagenase and trypsin. The single cell suspension obtained was then incubated with an anti-CD31, anti-CD105 antibody and with biotinylated isolectin B-4. The endothelial cells were harvested using magnetic bead separation with rat anti-mouse Ig- and streptavidin-conjugated microbeads. Endothelial cells were expanded and collected for subsequent analyses. The morphological and phenotypic features of these cultures remained stable over 10 passages in culture. There was no overgrowth of contaminating cells of non-endothelial origin at any stage.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the intestinal tract and is primarily comprised of Crohn’s disease (CD) and ulcerative colitis (UC). Several murine models that include both chemical induced and genetic models have been developed that mimic some aspects of either CD or UC. These models have been instrumental in our understanding of IBD. Of the chemical induced colitis models, dextran sodium sulfate (DSS) induced colitis model is a relatively simple and very widely used model of experimental colitis.

Inflammatory bowel disease (IBD) including Crohn’s disease and ulcerative colitis are characterized by chronic, progressive and relapsing inflammatory disorders. Existing evidence indicate that IBD is associated with a higher risk of developing CAC, which is directly related to the duration and extent of colitis. Thus, animal models have been developed to understand the biology of colitis and CAC. The most commonly used model of colitis is to treat with dextran sodium sulfate (DSS). DSS given in the drinking water is toxic to the colonic epithelial lining and induces bloody diarrhea, ulceration and inflammation, similar to colitis in IBD patients. To study CAC, DSS treatment is combined with a single intraperitoneal injection of the DNA alkylation reagent Azoxymethane (AOM).

Different vaccine and adjuvant combinations are known to rapidly induce antigen presenting cell (APC) maturation and pro-inflammatory cytokine and production, which in turn play an important role in the priming of antigen-specific T cells. Measuring cytokine production systemically in the serum fails to detect localized responses in the lymph nodes draining a subcutaneous immunization site. On the other hand, stimulating APC with vaccine formulations in vitro lacks the complexity of the lymph node microenvironment and the presence of other in vivo factors. Here we analyse cytokine production directly in vaccine draining lymph nodes (dLN) extracted early after in vivo vaccination. To do this we perform cytokine multiplex analysis of supernatants from whole dLN cell suspensions following a brief ex vivo incubation.

Chronic inflammation drives initiation of hepatocellular carcinoma (HCC), but the underlying mechanisms linking inflammation and tumor formation remain obscure. In this study, Xenograft tumor assay was used to determine the tumorigenic activity of hepatoma cells with ISX over expression on nude mice in vivo.

This protocol allows to measure the levels cytokines - such as VEGFs, CXCLs cytokines, PDGF or FGF - from fresh samples but also frozen tumors. The advantage of this method is to use very few micrograms of biological material and the protocol is carried out quickly.