Angiogenesis is an important process in cell development, especially in cancer. Vascular endothelial growth factor (VEGF) signaling is an important regulator of angiogenesis. Several therapies that act against VEGF signal transduction have been developed, including YN968D1, which is a potent inhibitor of the VEGF signaling pathway. This study investigated the antitumor activity of YN968D1 (apatinib mesylate) in vitro and in vivo. YN968D1 potently suppressed the kinase activities of VEGFR-2, c-kit and c-src, and inhibited cellular phosphorylation of VEGFR-2, c-kit and PDGFRb. YN968D1 effectively inhibited proliferation, migration and tube formation of human umbilical vein endothelial cells induced by FBS, and blocked the budding of rat aortic ring. In vivo, YN968D1 alone and in combination with chemotherapeutic agents effectively inhibited the growth of several established human tumor xenograft models with little toxicity. A phase I study of YN968D1 has shown encouraging antitumor activity and a manageable toxicity profile. These findings suggest that YN968D1 has promise as an antitumor drug and might have clinical benefits.
The present meta-analysis provides evidence that MSD improves outcomes of glycemic control, body weight and cardiovascular risk factors in T2D patients.
BackgroundIncretin-based agents, including dipeptidyl peptidase-4 inhibitors (DPP-4Is) and glucagon-like peptide-1 agonists (GLP-1As), work via GLP-1 receptor for hyperglycemic control directly or indirectly, but have different effect on cardiovascular (CV) outcomes. The present study is to evaluate and compare effects of incretin-based agents on CV and pancreatic outcomes in patients with type 2 diabetes mellitus (T2DM) and high CV risk.MethodsSix prospective randomized controlled trials (EXMAINE, SAVOR-TIMI53, TECOS, ELIXA, LEADER and SUSTAIN-6), which included three trials for DPP-4Is and three trials for GLP-1As, with 55,248 participants were selected to assess the effect of different categories of incretin-based agents on death, CV outcomes (CV mortality, major adverse CV events, nonfatal myocardial infarction, nonfatal stroke, heart failure hospitalization), pancreatic events (acute pancreatitis and pancreatic cancer) as well as on hypoglycemia.ResultsWhen we evaluated the combined effect of six trials, the results suggested that incretin-based treatment had no significant effect on overall risks of CV and pancreatic outcomes compared with placebo. However, GLP-1As reduced all-cause death (RR = 0.90, 95% CI 0.82–0.98) and CV mortality (RR = 0.84, 95% CI 0.73–0.97), whereas DPP-4Is had no significant effect on CV outcomes but elevated the risk for acute pancreatitis (OR = 1.76, 95% CI 1.14–2.72) and hypoglycemia (both any and severe hypoglycemia), while GLP-1As lowered the risk of severe hypoglycemia.ConclusionsGLP-1As decreased risks of all-cause and CV mortality and severe hypoglycemia, whereas DPP-4Is had no effect on CV outcomes but increased risks in acute pancreatitis and hypoglycemia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12933-017-0512-z) contains supplementary material, which is available to authorized users.
Jasmonates (JAs) are essential plant hormones that play important roles in the regulation of plant growth and the response to environmental stress. In the JA signaling pathway, the core transcription factors are a class of basic helix-loop-helix (bHLH) proteins, including MYC2, MYC3, and MYC4, that have different regulatory capacities. Here, we report the 2.7 Å crystal structure of the MYC2 bHLH domain complexed with G-box DNA, showing a cis-tetrameric structure. Biochemical assays confirmed that full-length MYC2 forms a stable homo-tetramer both in solution and in DNA-bound states, whereas MYC3 forms only a homodimer. Isothermal titration calorimetry (ITC) assays demonstrated that tetramerization enhanced DNA binding affinity, and fluorescence resonance energy transfer (FRET) assay indicated DNA looping potential of tetrameric MYC2. Luciferase assay further confirmed the importance of tetramerization in transcriptional regulation. Our studies provide a mechanistic explanation for the regulatory differences of MYC transcription factors.
Trastuzumab emtansine (T‐DM1), an antibody–drug conjugate (ADC) consisting of human epidermal growth factor receptor 2 (HER2)‐targeted mAb trastuzumab linked to antimicrotubule agent mertansine (DM1), has been approved for the treatment of HER2‐positive metastatic breast cancer. Acquired resistance has been a major obstacle to T‐DM1 treatment, and mechanisms remain incompletely understood. In the present study, we established a T‐DM1‐resistant N87‐KR cell line from HER2‐positive N87 gastric cancer cells to investigate mechanisms of acquired resistance and develop strategies for overcoming it. Although the kinetics of binding, internalization, and externalization of T‐DM1 were the same in N87‐KR cells and N87 cells, N87‐KR was strongly resistant to T‐DM1, but remained sensitive to both trastuzumab and DM1. T‐DM1 failed to inhibit microtubule polymerization in N87‐KR cells. Consistently, lysine‐MCC‐DM1, the active T‐DM1 metabolite that inhibits microtubule polymerization, accumulated much less in N87‐KR cells than in N87 cells. Furthermore, lysosome acidification, achieved by vacuolar H+‐ATPase (V‐ATPase), was much diminished in N87‐KR cells. Notably, treatment of sensitive N87 cells with the V‐ATPase selective inhibitor bafilomycin A1 induced T‐DM1 resistance, suggesting that aberrant V‐ATPase activity decreases T‐DM1 metabolism, leading to T‐DM1 resistance in N87‐KR cells. Interestingly, HER2‐targeted ADCs containing a protease‐cleavable linker, such as hertuzumab‐vc‐monomethyl auristatin E, were capable of efficiently overcoming this resistance. Our results show for the first time that a decrease in T‐DM1 metabolites induced by aberrant V‐ATPase activity contributes to T‐DM1 resistance, which could be overcome by HER2‐targeted ADCs containing different linkers, including a protease‐cleavable linker. Accordingly, we propose that V‐ATPase activity in lysosomes is a novel biomarker for predicting T‐DM1 resistance.
These data demonstrate that the use of lobaplatin alone or in combination with antitubulin agents might be a rational and novel therapeutic strategy for human NSCLC and warrants further clinical investigation.
Objectives: To detect microRNA (miR)-126 expression and its correlation with vascular endothelial growth factor (VEGF) levels in placentas from patients with pre-eclampsia compared with those from normotensive pregnancies. Methods: miR-126 expression, and VEGF mRNA and protein levels, in placentas collected sequentially from patients with pre-eclampsia and normotensive pregnancies were measured using real-time reverse transcription-polymerase chain reaction and Western blot, respectively. The relationship between miR-126 and VEGF expression was analysed statistically. The regulatory effect of miR-126 on VEGF expression in human placental choriocarcinoma (BeWo) cells in vitro was also investigated. Results: miR-126 expression was decreased, and VEGF mRNA and protein levels were significantly lower, in placentas from patients with pre-eclampsia (n ¼ 115) compared with placentas from normotensive pregnancies (n ¼ 115). A positive correlation was found between VEGF mRNA and miR-126 expression (r ¼ 0.79). In addition, miR-126 overexpression significantly upregulated VEGF expression in BeWo cells, whereas miR-126 downregulation decreased VEGF expression. Conclusions: miR-126 was downregulated in placentas from patients with pre-eclampsia and this correlated with decreased VEGF expression. These findings indicate that miRNA-126 may be involved in pre-eclampsia pathogenesis and could be a potential biomarker for this disease.
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