Matrine has potent antitumor activities in HepG2 cells and may be used as a novel effective reagent in treatment of hepatocellular carcinoma.
CD4 is a T lymphocyte receptor for major histocompatibility complex class II antigens. It is referred to as coreceptor because it synergizes with the T cell receptor for antigen when both receptors become engaged simultaneously. We show here in mice that when engaged by antibody independently of the T cell antigen receptor, CD4 induces T cells to undergo apoptosis. Several features of this process were identified. The expression of an intact Fas protein is a requirement for CD4-mediated T cell death. Mice homozygous for the lpr mutation which are defective in the expression of Fas and in their ability to delete lymphocytes apoptotically fail to delete anti-CD4-reactive T cells. Sessile anti-CD4-reactive T cells leave their homing environment in lymphoid organs and modulate their cell surface molecules, e.g. CD2, CD3, CD4. A massive influx of lymphoid cells with null-cell phenotype occurs in the blood where they begin to reexpress cell surface markers. With their arrival in the circulation, anti-CD4-reactive T cells develop features of DNA degradation typical of apoptosis. More than one third of the circulating lymphoid cells show apoptotic features 7-8 h after anti-CD4 injection. Their frequency declines subsequently presumably due to their physical disintegration via shedding of apoptotic bodies and phagocytosis. Our data show that when not obliged to the activation process by the antigen receptor, CD4 can mediate deletion signals. Thus, besides functioning as coreceptor with the antigen receptor, CD4 has a function of its own in facilitating the induction of apoptosis.
Background Transfer of noncoding microRNAs (miRNAs) by extracellular vesicles (EVs) promotes the development of chemoresistance in many tumor types. Additionally, restoration or depletion of several miRNAs has been observed in multiple cancer types including gastric cancer (GC). In this present study, we aimed to investigate the mechanism of miR-130b-3p in M2 macrophage-derived EVs in the development of GC through regulation of mixed lineage leukemia 3 (MLL3) and grainyhead-like 2 (GRHL2). Methods Expression of miR-130b-3p and GRHL2 was quantified in 63 pairs of cancerous and noncancerous gastric tissues. The predicted binding between miR-130b-3p and MLL3, together with the enrichment of MLL3, H3K4me1, and H3K27ac in gene enhancer region, was verified by luciferase activity assay and chromatin immunoprecipitation. Effects of miR-130b-3p on GC cell proliferation, apoptosis, migration and invasion, as well as tube formation of human umbilical endothelial vein cells (HUEVCs) were further determined by gain- and loss-of function assays in vitro. Results miR-130b-3p was upregulated in GC tissues, and miR-130b-3p promoted survival, metastasis and angiogenesis of GC cells as well as enhanced tumor formation and angiogenesis in GC in vivo. Additionally, miR-130b-3p delivered in M2 macrophage-derived EVs promoted survival, migration, invasion, and angiogenesis of GC cells. Notably, MLL3 inhibited GC cell proliferation, migration, invasion, and vessel-like tube formation of HUEVCs by increasing GRHL2. Furthermore, downregulation of miR-130b-3p in M2 macrophage-derived EVs or upregulation of GRHL2 inhibited tumor formation and angiogenesis in GC. Conclusion This study highlights that EVs loaded with the specific miRNA cargo miR-130b-3p mediate communication between M2 macrophages and cancer cells in the tumor microenvironment through the modulation of MLL3 and GRHL2 in GC.
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