Development of a Multi-Step Leukemogenesis Model of MLL-Rearranged Leukemia Using Humanized Mice

Mixed-lineage-leukemia (MLL) fusion oncogenes are intimately involved in acute leukemia and secondary therapy-related acute leukemia. To understand MLL-rearranged leukemia, several murine models for this disease have been established. However, the mouse leukemia derived from mouse hematopoietic stem cells (HSCs) may not be fully comparable with human leukemia. Here we developed a humanized mouse model for human leukemia by transplanting human cord blood-derived HSCs transduced with an MLL-AF10 oncogene into a supra-immunodeficient mouse strain, NOD/Shi-scid, IL-2Rγ−/− (NOG) mice. Injection of the MLL-AF10-transduced HSCs into the liver of NOG mice enhanced multilineage hematopoiesis, but did not induce leukemia. Because active mutations in ras genes are often found in MLL-related leukemia, we next transduced the gene for a constitutively active form of K-ras along with the MLL-AF10 oncogene. Eight weeks after transplantation, all the recipient mice had developed acute monoblastic leukemia (the M5 phenotype in French-American-British classification). We thus successfully established a human MLL-rearranged leukemia that was derived in vivo from human HSCs. In addition, since the enforced expression of the mutant K-ras alone was insufficient to induce leukemia, the present model may also be a useful experimental platform for the multi-step leukemogenesis model of human leukemia

Lipoxin A (4) reduces lipopolysaccharide-induced inflammation in macrophages and intestinal epithelial cells through inhibition of nuclear factor-kappaB activation. J Pharmacol Exp Ther 332: 541–548

ABSTRACT Lipoxins, which are bioactive lipids derived from -6 polyunsaturated fatty acids, play important roles in various biological functions. In this study, the anti-inflammatory effects of lipoxin A 4 (LXA4; 5S,6R,15S-trihydroxy-7,9,13-trans-11-eicosatetraenoic acid) were investigated in in vitro cultured cell experiments and in vivo animal experiments. In mouse peritoneal macrophages and mouse macrophage cell line RAW264.7 cells, LXA4 reduced the lipopolysaccharide (LPS)-induced increase in the mRNA expression level of tumor necrosis factor (TNF)-␣. LXA4 also reduced the LPS-induced nuclear translocation of nuclear factor-B (NF-B). In an LPS-induced acute inflammation mouse model, the injection of LXA4 at 5 g/kg b.wt. led to down-regulation of the TNF-␣ level in serum and the TNF-␣ mRNA expression level in intestinal epithelial cells. Moreover, LXA4 reduced the LPS-caused phosphorylation of IB kinases, IB, and NF-B, the degradation of IB, and the nuclear translocation of NF-B in intestinal epithelial cells. In a coculture system using RAW264.7 cells and human colon carcinoma cell line Caco-2 cells, treatment with LXA4 to Caco-2 cells led to reduction of LPS-evoked TNF-␣ production in RAW264.7 cells and interleukin-8 mRNA expression in Caco-2 cells. These results indicate that LXA4 exerts anti-inflammatory effects through inhibition of NF-B activation, and, therefore, LXA4 may be useful as a therapeutic strategy against intestinal mucosa inflammation. Lipoxins, which are composed of lipoxin A 4 (LXA4; 5S,6R,15S-trihydroxy-7,9,13-trans-11-eicosatetraenoic acid) and lipoxin B 4 (LXB4; 5S,14R,15S-trihydroxy-6E,8Z,10E,12E-eicosatetraenoic acid), are bioactive lipids derived from -6 polyunsaturated fatty acids. Lipoxins play important roles in various biological functions, especially in inflammatory processes. In contrast to prostaglandins (PGs) and leukotrienes (LTs), which are proinflammatory molecules, lipoxins mainly act in the resolution phase of inflammatory responses and promote the termination of inflammatory processe

Serum manganese superoxide dismutase and thioredoxin are potential prognostic markers for hepatitis C virus-related hepatocellular carcinoma

AIM: To evaluate the clinical significance of oxidative stress markers in patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC)

The co-existence of NS5A and NS5B resistance-associated substitutions is associated with virologic failure in Hepatitis C Virus genotype 1 patients treated with sofosbuvir and ledipasvir

<div><p>Objective</p><p>The present study aimed to reveal the factors associated with virologic failure in sofosbuvir and ledipasvir (SOF/LDV)-treated patients, and identify baseline NS5A or NS5B resistance-associated substitutions (RASs).</p><p>Methods</p><p>Four hundred ninety-three patients with Hepatitis C Virus (HCV) genotype 1b infection were treated with SOF/LDV; 31 had a history of interferon (IFN)-free treatment with daclatasvir and asunaprevir. The effect of baseline RASs on the response to SOF/LDV therapy was analyzed.</p><p>Results</p><p>Overall, a sustained virologic response at 12 weeks (SVR12) was achieved in 476 patients (96.6%). The SVR12 rates in the patients with IFN-free treatment-naïve and retreatment were 97.6% and 80.6%, respectively. HCV elimination was not achieved in 17 patients, 11 (including 5 with IFN-free retreatment) of whom had virologic failure. Eight patients had coexisting NS5A RASs of Q24, L28 and/or R30, L31, or Y93 and one patient had coexisting NS5A RASs of P32L and A92K. Interestingly, 10 and 8 patients had NS5B A218S and C316N RAS respectively. According to a multivariate analysis, coexisting NS5A RASs, NS5A P32 RAS, NS5B A218 and/or C316 RASs, and γ-glutamyltranspeptidase were associated with virologic failure. In the naïve patients, all patients without NS5B A218 and/or C316 RAS achieved an SVR12. Notably, the SVR12 rates of patients with coexisting NS5A and NS5B RASs were significantly lower (83.3%).</p><p>Conclusions</p><p>Although SOF/LDV therapy resulted in a high SVR12 rate, coexisting NS5A and NS5B RASs were associated with virologic failure. These results might indicate that the coexisting baseline RASs influence the therapeutic effects of SOF/LDV.</p></div

The virologic response rates (intention-to-treat analysis).

<p>The sustained virologic response (SVR) 12 rates of the IFN-free treatment-naïve patients and IFN-free retreatment patients were 97.6% and 80.6% respectively.</p

The sustained virologic response (SVR) 12 rate in the patients with co-existing NS5A and NS5B RASs.

<p>The interferon (IFN) free-naïve patients with coexisting resistance-associated substitutions (RASs) of Q24, L28, and/or R30, L31, or Y93 and NS5B A218 and/or C316 had a significantly lower sustained virologic response (SVR) 12 rate in comparison to the patients without these RASs.</p