Histological and ultrastructural comparison of cauterization and thrombosis stroke models in immune-deficient mice

<p>Abstract</p> <p>Background</p> <p>Stroke models are essential tools in experimental stroke. Although several models of stroke have been developed in a variety of animals, with the development of transgenic mice there is the need to develop a reliable and reproducible stroke model in mice, which mimics as close as possible human stroke.</p> <p>Methods</p> <p>BALB/Ca-RAG2^-/-γc^-/-mice were subjected to cauterization or thrombosis stroke model and sacrificed at different time points (48hr, 1wk, 2wk and 4wk) after stroke. Mice received BrdU to estimate activation of cell proliferation in the SVZ. Brains were processed for immunohistochemical and EM.</p> <p>Results</p> <p>In both stroke models, after inflammation the same glial scar formation process and damage evolution takes place. After stroke, necrotic tissue is progressively removed, and healthy tissue is preserved from injury through the glial scar formation. Cauterization stroke model produced unspecific damage, was less efficient and the infarct was less homogeneous compared to thrombosis infarct. Finally, thrombosis stroke model produces activation of SVZ proliferation.</p> <p>Conclusions</p> <p>Our results provide an exhaustive analysis of the histopathological changes (inflammation, necrosis, tissue remodeling, scarring...) that occur after stroke in the ischemic boundary zone, which are of key importance for the final stroke outcome. This analysis would allow evaluating how different therapies would affect wound and regeneration. Moreover, this stroke model in RAG 2^-/-γC ^-/-allows cell transplant from different species, even human, to be analyzed.</p

Dual targeting of histone methyltransferase G9a and DNA-methyltransferase 1 for the treatment of experimental hepatocellular carcinoma

Epigenetic modifications like DNA and histone methylation functionally cooperate fostering tumor growth, including that of hepatocellular carcinoma (HCC). Pharmacological targeting of these mechanisms may open new therapeutic avenues. We aimed to determine the therapeutic efficacy and potential mechanism of action of our new dual G9a histone-methyltransferase and DNA-methytransferase 1 (DNMT1) inhibitor in human HCC cells and their crosstalk with fibrogenic cells. The expression of G9a and DNMT1, along with that of their molecular adaptor ubiquitin-like with PHD and RING finger domains-1 (UHRF1), was measured in human HCCs (n=268), peritumoral tissues (n=154) and HCC cell lines (n=32). We evaluated the effect of individual and combined inhibition of G9a and DNMT1 on HCC cells growth by pharmacological and genetic approaches. The activity of our lead compound, CM-272, was examined in HCC cells under normoxia and hypoxia, human hepatic stellate cells and LX2 cells, and xenograft tumors formed by HCC or combined HCC+LX2 cells. We found a significant and correlative overexpression of G9a, DNMT1 and UHRF1 in HCCs in association with poor prognosis. Independent G9a and DNMT1 pharmacological targeting synergistically inhibited HCC cell growth. CM-272 potently reduced HCC and LX2 cells proliferation and quelled tumor growth, particularly in HCC+LX2 xenografts. Mechanistically, CM-272 inhibited the metabolic adaptation of HCC cells to hypoxia, and induced a differentiated phenotype in HCC and fibrogenic cells. The expression of the metabolic tumor suppressor gene fructose-1,6-bisphosphatase (FBP1), epigenetically repressed in HCC, was restored by CM-272. CONCLUSION: Combined targeting of G9a/DNMT1 with compounds like CM-272 is a promising strategy for HCC treatment. Our findings also underscore the potential of differentiation therapy in HCC. This article is protected by copyright. All rights reserved