ABSTRACT
The immune checkpoint programmed cell death-ligand 1(PD-L1)-mediated immunosuppression is among the important features of tumor. PD-L1, an immunosuppressant, can induce T cell failure by binding to programmed cell death-1(PD-1). Thus, the key to restoring the function of T cells is inhibiting the expression of PD-L1. The Chinese medicinal Atractylodis Macrocephalae Rhizoma(AMR) has the anti-tumor, anti-inflammatory, antioxidant, and hypoglycemic activities, and the polysaccharide in AMR(PAMR) plays a crucial role in immunoregulation, but the influence on the immune checkpoints which are closely related to immunosuppression has not been reported. MicroRNA-34 a(miR-34 a) expression in esophageal carcinoma tissue is significantly lower than that in normal tissue. This study aims to investigate the inhibitory effect of PAMR on esophageal carcinoma cells, and the relationship between its inhibitory effect on PD-L1 expression and miR-34 a, which is expected to clarify the anti-tumor mechanism of PAMR. Firstly, different human esophageal carcinoma cell lines(EC9706, EC-1, TE-1, EC109 cells) were screend out, and expression of PD-L1 was determined. Then, EC109 cells, with high expression of PD-L1, were selected for further experiment. The result showed that PAMR suppressed EC109 cell growth. According to the real-time quantitative PCR(qPCR) and Western blot, it significantly suppressed the mRNA and protein expression of PD-L1, while promoting the expression of tumor suppressor miR-34 a. The confocal microscopy and luci-ferase assay proved that PAMR alleviated the inhibitory effect of PD-L1 while blocked miR-34 a. Additionally, the expression of PD-L1 was controlled by miR-34 a, and the combination of miR-34 a inhibitor with high-dose PAMR reversed the inhibitory effect of PAMR on PD-L1 protein expression. Thus, the PAMR may inhibit PD-L1 by increasing the expression of miR-34 a and regulating its downstream target genes. In conclusion, PAMR inhibits the expression of PD-L1 mainly by inducing miR-34 a.
Subject(s)
Humans , B7-H1 Antigen/pharmacology , Carcinoma , Cell Proliferation , MicroRNAs/metabolism , Polysaccharides/pharmacologyABSTRACT
Objective: To investigate the antitumor effects of melittin on UMR-106 cells with osteosarcoma xenografts in nude mice and its action on vasculogenic mimicry (VM) in vitro and in vivo. Methods: A three-dimensional cell culture system was formed on matrigel coats in vitro. Inhibitory action of melittin on the VM of UMR-106 cells was observed in vitro. Osteosarcoma was orthotopically transplanted in nude mice. The mice were randomly divided into three groups: normal saline (NS)-treated group, melittin group (320 μg/kg) and DDP-treated group(2 mg/kg). The drug was administered intratumorally for 10 d. The tumor volume and weight inhibition ratio were calculated, respectively. The VM density in tumor tissues was detected by CD34 and PAS double staining in vivo. The expressions of hypoxia-inducible factor-1α(HIF-1α) and matrix metalloproteinase-2 (MMP-2) proteins were determined by immunohistochemical staining and Western blot. Results: Melittin broke down the mesh and round architectonic of VM in osteosarcoma in vitro. The tumor weight inhibition ratio was 38.92% and the volume inhibition ratio was 43.04%. The VM density and the expressions of HIF-1α and MMP-2 proteins were decreased in the melittin group than that in the NS-treated group (P <0.01). Conclusion: Melittin markedly inhibites the growth of osteosarcoma UMR-106 xenografts in nude mice. The mechanism may be due to down-regulation of HIF-1α and MMP-2 expression and the inhibition of VM.
ABSTRACT
Activating blood circulation to remove stasis method is an important therapy of TCM, which can be matched with various methods, as qi-supplementing, qi-regulating, heat-clearing with detoxication, meridian warming, wind-dispelling to remove dampness, yin-nourishing, phlegm-dissolving to alleviate depression and visceral dredging by purgation, to produce various effects on angiogenesis. Its positive or negative impacts on quality or quantity of angio-genetic regulatory factor play a crucial part for the effects. This article explores the effect and mechanism of activating blood circulation to remove stasis method on angiogenesis bi-directionally.