We have shown previously that chromosome VI of Saccharomyces cerevisiae contains nine origins of DNA replication that differ in initiation frequency and replicate sequentially during the S phase of the cell cycle. Here we show that there are links between activation of these multiple origins and regulation of S-phase progression. We study the effects of a DNA-damaging agent, methyl methane sulphonate (MMS), and of mutations in checkpoint genes such as rad53 on the activity of origins, measured by two-dimensional gel analysis, and on cell-cycle progression, measured by fluorescence-activated cell sorting. We find that when MMS slows down S-phase progression it also selectively blocks initiation from late origins. A rad53 mutation enhances late and/or inefficient origins and releases the initiation block by MMS. Mutation of rad53 also results in a late origin becoming early replicating. We conclude that rad53 regulates the timing of initiation of replication from late origins during normal cell growth and blocks initiation from late origins in MMS-treated cells. rad53 is, therefore, involved in the cell's surveillance of S-phase progression. We also find that orc2, which encodes subunit 2 of the origin-recognition complex, is involved in suppression of late origins.
BackgroundLenvatinib is an oral inhibitor of multiple receptor tyrosine kinases (RTKs) targeting vascular endothelial growth factor receptor (VEGFR1-3), fibroblast growth factor receptor (FGFR1-4), platelet growth factor receptor α (PDGFR α), RET and KIT. Antiangiogenesis activity of lenvatinib in VEGF- and FGF-driven angiogenesis models in both in vitro and in vivo was determined. Roles of tumor vasculature (microvessel density (MVD) and pericyte coverage) as biomarkers for lenvatinib were also examined in this study.MethodWe evaluated antiangiogenesis activity of lenvatinib against VEGF- and FGF-driven proliferation and tube formation of HUVECs in vitro. Effects of lenvatinib on in vivo angiogenesis, which was enhanced by overexpressed VEGF or FGF in human pancreatic cancer KP-1 cells, were examined in the mouse dorsal air sac assay. We determined antitumor activity of lenvatinib in a broad panel of human tumor xenograft models to test if vascular score, which consisted of high MVD and low pericyte coverage, was associated with sensitivity to lenvatinib treatment. Vascular score was also analyzed using human tumor specimens with 18 different types of human primary tumors.ResultLenvatinib inhibited VEGF- and FGF-driven proliferation and tube formation of HUVECs in vitro. In vivo angiogenesis induced by overexpressed VEGF (KP-1/VEGF transfectants) or FGF (KP-1/FGF transfectants) was significantly suppressed with oral treatments of lenvatinib. Lenvatinib showed significant antitumor activity in KP-1/VEGF and five 5 of 7 different types of human tumor xenograft models at between 1 to 100 mg/kg. We divided 19 human tumor xenograft models into lenvatinib-sensitive (tumor-shrinkage) and relatively resistant (slow-growth) subgroups based on sensitivity to lenvatinib treatments at 100 mg/kg. IHC analysis showed that vascular score was significantly higher in sensitive subgroup than relatively resistant subgroup (p < 0.0004). Among 18 types of human primary tumors, kidney cancer had the highest MVD, while liver cancer had the lowest pericyte coverage, and cancers in Kidney and Stomach had highest vascular score.ConclusionThese results indicated that Lenvatinib inhibited VEGF- and FGF-driven angiogenesis and showed a broad spectrum of antitumor activity with a wide therapeutic window. MVD and pericyte-coverage of tumor vasculature might be biomarkers and suggest cases that would respond for lenvatinib therapy.
The Convoy Model of Social Relations is identified as a unifying conceptual framework within which to consider attachment and other close social relationships across the life span. Convoy data are provided for people aged 8 to 93 in both the United States and Japan. Data from community based representative samples in the Detroit (N = 1703) and Yokohama (N = 1842) metropolitan areas indicate age differences in all close relationships but gender differences only in very close relationships in the two countries. There was only one Age x Gender x Country interaction for number of people in close relations. Examination of role relationships suggest age differences overall but considerable similarities in the two countries.
This article examines age differences in positive, but especially negative, interactions in close relationships. Two community-based representative samples of people from 13 to 96 years of age from the United States and Japan were used to explore these relationships. Analyses indicate stability across age in positive interactions but a general decline in negative interactions in both countries. Three possible explanations for this age difference in negative interactions were examined: social maturity, familiarity, and contact frequency. Results provide most support for the contact frequency explanation. And finally, intercorrelations across relationships, that is, spouse, mother, father, child, and same-gender best friend, indicate moderate to high intercorrelations across all ages with a slight increase among older Japanese age groups. These results can be summarized as lending support to a generalized reduction in negative interactions with age but exceptions are noted in specific relationships and cultural traditions.
Recent studies have implicated dysfunctional endothelial nitric-oxide synthase (eNOS) as a common pathogenic pathway in diabetic vascular complications. However, functional consequences are still incompletely understood. To determine the role of eNOS-derived nitric oxide (NO) in diabetic nephropathy, we induced diabetes in eNOS knockout (KO) and wild-type (WT) mice on the C57BL6 background, using low-dose streptozotocin injection, and we investigated their glomerular phenotype at up to 20 weeks of diabetes. Although the severity of hyperglycemia in diabetic eNOS KO mice was similar to diabetic WT mice, diabetic eNOS KO mice developed overt albuminuria, hypertension, and glomerular mesangiolysis, whereas diabetic WT and nondiabetic control mice did not. Glomerular hyperfiltration was also significantly reduced in diabetic eNOS KO mice. Electron micrographs from diabetic eNOS KO mice revealed an injured endothelial morphology, thickened glomerular basement membrane, and focal foot process effacement. Furthermore, the anionic sites at glomeru- Nitric oxide (NO) is a free radical that mediates diverse functions in a range of biological systems.1 NO is produced by a family of nitric-oxide synthase (NOS) enzymes to catalyze the stoichiometric five-electron oxidation of the terminal quanidino group of L-arginine to produce NO and L-citrulline. Three NOS isoforms have been distinguished in mammalian species: neuronal NOS, inducible NOS, which is expressed in a variety of activated tissues, and endothelial NOS (eNOS).1 In the vasculature, NO is mostly generated by eNOS, and the generated NO plays a crucial role in maintaining vascular homeostasis, including vascular tone, leukocyte adhesion to endothelium, proliferation of vascular smooth muscle cells, and platelet aggregation and adhesion to the vessel wall.
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