IL-8-induced CXCR2 down-regulation in circulating monocytes in hepatocellular carcinoma is partially dependent on MAGL.

BACKGROUND: CXC-chemokine receptor 2 (CXCR2) expression was found to be down-regulated on circulating monocytes of cancer patients. Here, we analyze the percentage of CD14+CXCR2+ monocyte subsets in hepatocellular carcinoma (HCC) patients, and investigate the mechanisms that regulate CXCR2 surface expression on monocytes and its biological function. METHODS: Flow cytometry was used to analyze the proportion of the CD14+CXCR2+ subset from the total circulating monocytes of HCC patients. Interleukin 8 (IL-8) levels were measured from serum and ascites, and their correlation with the CD14+CXCR2+ monocyte subset proportion was calculated. THP-1 cells were cultured in vitro and treated with recombinant human IL-8 and CXCR2 surface expression was analyzed. CXCR2 was knocked down to examine how it affects the antitumor activity of monocytes. Finally, a monoacylglycerol lipase (MAGL) inhibitor was added to analyze its effect on CXCR2 expression. RESULTS: A decrease in the proportion of the CD14+CXCR2+ monocyte subset was observed in HCC patients compared with healthy controls. CXCR2+ monocyte subset proportion was associated with the AFP value, TNM stage, and liver function. Overexpression of IL-8 was observed in the serum and ascites of HCC patients, and negatively correlated with CXCR2+ monocyte proportion. IL-8 decreased CXCR2 expression in THP-1 cells, contributing to decreased antitumor activity toward HCC cells. MAGL expression in THP-1 cells was up-regulated after IL-8 treatment, and the MAGL inhibitor partially reversed the effects of IL-8 on CXCR2 expression. CONCLUSIONS: Overexpression of IL-8 drives CXCR2 down-regulation on circulating monocytes of HCC patients, which could be partially reversed by a MAGL inhibitor.

Therapeutic effect of secretome from TNF-α stimulated mesenchymal stem cells in an experimental model of corneal limbal stem cell deficiency.

AIM: To explore the secretome efficacy in tumor necrosis factor (TNF)-α stimulated mouse mesenchymal stem cells (MSCs) in a murine model of corneal limbal alkali injury. METHODS: Corneal limbal stem cell deficiency (LSCD) was created in the eyes of male C57 mice. Concentrated conditioned medium from TNF-α stimulated MSCs (MSC-CMT) was applied topically for 4wk, with basal medium and conditioned medium from MSCs as controls. Corneal opacification, corneal inflammatory response, and corneal neovascularization (NV) were evaluated. Corneal epithelial cell apoptosis, corneal conjunctivation, and inflammatory cell infiltration were assessed with TUNEL staining, CK3 and Muc-5AC immunostaining, and CD11b immunofluorescence staining, respectively. The effect of TSG-6 was further evaluated by knockdown with short hairpin RNA (shRNA). RESULTS: Compared to the controls, topical administration of MSC-CMT significantly ameliorated the clinical symptoms of alkali-induced LSCD, with restrained corneal NV, reduced corneal epithelial cell apoptosis, and inhibition of corneal conjunctivation. In addition, MSC-CMT treatment significantly reduced CD11b+ inflammatory cell infiltration, and inhibited the expression of pro-inflammatory cytokines (IL-1ß, TNF-α and IL-6). Furthermore, the promotion of corneal epithelial reconstruction by MSC-CMT was largely abolished by TSG-6 knockdown. CONCLUSION: Our study provides evidence that MSC-CMT enhances the alleviation of corneal alkali injuries, partially through TSG-6-mediated anti-inflammatory protective mechanisms. MSC-CMT may serve as a potential strategy for treating corneal disorders.

MicroRNA-184 Modulates Doxorubicin Resistance in Osteosarcoma Cells by Targeting BCL2L1.

BACKGROUND Early metastasis of osteosarcoma (OS) is highly lethal and responds poorly to drug and radiation therapies. MicroRNAs (miRNAs) are a class of small noncoding RNAs that modulate gene expression at the post-transcriptional level. However, the detailed functions of specific miRNAs are not entirely understood. The aim of the present study was to investigate the role of miR-184 as a mediator of drug resistance in human osteosarcoma. MATERIAL AND METHODS qRT-PCR was used to analyze the expression level of miR-184 in OS cell line U-2 OS and MG-63 treated with doxorubicin. MiR-184 agomir or miR-184 antagomir was transferred into cells to regulated miR-184. The target of miR-184 was predicted by TargetScan and confirmed by luciferase reporter assay. Bcl-2-like protein 1 (BCL2L1) expression was detected by Western blot. Cell apoptosis was determined by Annexin V staining and analysis by flow cytometry. RESULTS Doxorubicin induced time-dependent expression of miR-184 in OS cell line U-2 OS and MG-63. Luciferase reporter assay identified BCL2L1 as the direct target gene of miR-184. Furthermore, doxorubicin reduced BCL2L1 expression, which was reversed by miR-184 overexpression and further decreased by miR-184 inhibition in OS cells. In addition, miR-184 agomir reduced doxorubicin-induced cell apoptosis, whereas miR-184 antagomir enhanced apoptosis in OS cells, suggesting that up-regulation of miR-184 contributes to chemoresistance of the OS cell line. CONCLUSIONS Our data show that miR-184 was up-regulated in OS patients treated with doxorubicin therapy and leads to poor response to drug therapy by targeting BCL2L1.