Substantial growth inhibition and apoptosis without evidence of differentiation were induced in most malignant lymphocytic cells treated with 1-2 microM As2O3. As2O3 may prove useful in the treatment of malignant lymphoproliferative disorders.
Post-transplant parenteral nutritional support combined with omega-3 fatty acids can significantly improve the liver injury, reduce the infectious morbidities, and shorten the post-transplant hospital stay.
Posttransplant PN support can greatly improve metabolism of protein and nutrition states of patients. ω-3 fatty acid-supplemented PN significantly reduces injury of the transplanted liver, decreases the incidence of infectious morbidities, and shortens posttransplant hospital stay.
Kupffer cells (KCs) contribute to liver fibrosis resolution by production of a large spectrum of matrix metalloproteinases (MMPs). MMP9 is a major MMP expressed by KCs. However, its role in liver fibrosis resolution remains unclear. In this study, rodent liver fibrosis was induced by intraperitoneal thioacetamide (TAA) and the resolution process was initiated by TAA withdrawal. The role of KC-derived MMP9 in fibrolysis was investigated by adoptive transfer of KCs with or without MMP9 following their depletion. The levels of serum alanine aminotransferase (ALT) and hepatic cytokines were measured during fibrosis regression. The mRNA levels of MMPs and tissue inhibitor of metalloproteinases (TIMPs) were analyzed as well. It was found that removing KCs delayed fibrosis resolution. Adoptive transfer of KCs from WT animals promoted liver fibrosis resolution, compared with transfer of KCs from MMP9-/- mice. Depletion of KCs also resulted in prolonged liver wound healing, which was reversed partially by transferred KCs from either WT or MMP9-/- mice. Likewise, the absence of KCs led to reduction in MMPs mRNA levels and elevation in TIMPs mRNA levels. The expression patterns of MMPs or TIMPs were restored by adoptive transfer of the wild-type but not MMP9-/- KCs. In addition, liver fibrosis resolution was accelerated in MMP9-/- mice by adoptive transferred KCs from WT animals, compared to the KCs from MMP9-/- mice. Overall, KC-derived MMP9 plays a critical role in fibrosis resolution, which might serve as the foundation for developing anti-fibrosis therapy.
Ubiquitin-dependent proteolysis makes a major contribution to decreasing the levels of p27. Ubiquitindependent proteolysis of p27 kip1 is growth and cell cycle regulated in two ways: first, skp2, a component of the E3-ubiquitin ligase, is growth regulated, and second, a kinase must phosphorylate the threonine-187 position on p27 so that it can be recognized by skp2. In vitro, p27 is phosphorylated by cyclin E-and cyclin A-associated cdk2 as well as by cyclin B1-cdk1. Having analyzed the effect of different cyclin-cyclin-dependent kinase complexes on ubiquitination of p27 in a reconstitution assay system, we now report a noncatalytic requirement for cyclin A-cdk2. Multiparameter flow cytometric analysis also indicates that p27 turnover correlates best with the onset of S phase, once the levels of cyclin A become nearly maximal. Finally, increasing the amount of both cyclin E-cdk2 and skp2 was less efficient at promoting p27 ubiquitination than was increasing the amount of cyclin A-cdk2 alone in extracts prepared from cultures of >93%-purified G 1 cells. Together these lines of evidence suggest that cyclin A-cdk2 plays an ancillary noncatalytic role in the ubiquitination of p27 by the SCF skp2 complex.
BackgroundThe tumor suppressor TP53 and its negative regulator MDM2 play crucial roles in carcinogenesis. Previous case-control studies also revealed TP53 72Arg>Pro and MDM2 309T>G polymorphisms contribute to the risk of common cancers. However, the relationship between these two functional polymorphisms and nasopharyngeal carcinoma (NPC) susceptibility has not been explored.MethodsIn this study, we performed a case-control study between 522 NPC patients and 722 healthy controls in a Chinese population by using PCR-RFLP.ResultsWe found an increased NPC risk associated with the MDM2 GG (odds ratio [OR] = 2.83, 95% confidence interval [CI] = 2.08-3.96) and TG (OR = 1.49, 95% CI = 1.16-2.06) genotypes. An increased risk was also associated with the TP53 Pro/Pro genotype (OR = 2.22, 95% CI = 1.58-3.10) compared to the Arg/Arg genotype. The gene-gene interaction of MDM2 and TP53 polymorphisms increased adult NPC risk in a more than multiplicative manner (OR for the presence of both MDM2 GG and TP53 Pro/Pro genotypes = 7.75, 95% CI = 3.53-17.58).ConclusionThe findings suggest that polymorphisms of MDM2 and TP53 genes may be genetic modifier for developing NPC.
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