Problem:The role of the long non-coding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) in the etiology of endometriosis is unknown. Method of Study: Expression of epithelial-mesenchymal transition (EMT) markerswas quantified using qRT-PCR, immunohistochemistry, and Western blotting. The proliferation, migration, and invasion of ectopic endometrial epithelial cells and Ishikawa cells were evaluated by MTT, EdU, wound healing, and transwell assays.Inflammatory cytokine levels were detected by ELISA. Luciferase assays were used to measure activity of the ZEB1 promoter site pGL3-P886.Results: AFAP1-AS1 levels were much higher in ectopic endometrial tissues than that in eutopic tissues. Expression of ZEB1, E-cadherin, and keratin was obviously higher in eutopic tissues than those in ectopic tissues. In contrast, expression of vimentin and N-cadherin was significantly lower in eutopic tissue than those in ectopic tissues.After knockdown of AFAP1-AS1, the morphology of endometrial epithelial cells varied from spindle fiber shaped to polygon epithelioid and proliferation, migration, and invasion were each inhibited. The knockdown of AFAP1-AS1 significantly inhibited expression from promoter site pGL3-P886 of the EMT-related transcription factor ZEB1. The size of subcutaneous tumours in nude mice was significantly reduced after down-regulation of AFAP1-AS1 expression. Conclusion:Higher expression of AFAP1-AS1 positively correlated with greater EMT in ectopic endometrium of patients with endometriosis. Knockdown of AFAP1-AS1 inhibited E2-induced activity of promoter site pGL3-P886 of transcription factor ZTB1, suggesting that AFAP1-AS1 knockdown inhibited growth of endometrial epithelial cells and that pathogenesis may be correlated with EMT.

Endometriosis is an inflammation-dependent gynecologic disorder. Increased cyclooxygenase-2 (COX-2) expression plays an important role in the development and progression of endometriosis. Lipoxin A4 (LXA4) is an endogenous anti-inflammation lipid and showed inhibitory effects on the development of endometriosis; however, the mechanism remains unclear. In this study, the overexpression of COX-2 was observed in ectopic endometrium of endometriosis patients compared to the normal endometrium of controls. Lipoxin A4 efficiently suppressed IL-1β-induced COX-2 protein expression in ectopic endometriotic stromal cells (ESCs) via its receptor, formyl peptide receptor 2/lipoxin A4 receptor (FPR2/ALX). Antagonism of FPR2/ALX eliminated the inhibitory effect by LXA4. IL-1β induced the activation of mitogen-activated protein kinases (MAPKs), which can promote the expression of COX-2. Pretreatment of ESCs with LXA4 inhibited the phosphorylation of p38 MAPK induced by IL-1β. These findings suggest that inflammation and MAPKs pathways respond for the abnormal expression of COX-2, which can elucidate the pathophysiology of endometriosis. Moreover, LXA4 suppressed IL-1β-induced COX-2 expression through inhibiting the p38 MAPK signaling protein. This research contributes for better understanding of the cellular and biological events of inflammation and anti-inflammation-mediated regulation in endometriosis.

Sialic acid‐binding immunoglobulin‐like lectin‐15 (Siglec‐15) has been identified as a novel potential target for cancer immunotherapy. Here, we explored the role of Siglec‐15 in human hepatoma cells. In this study, we found that the expression of Siglec‐15 is substantially upregulated in liver cancer tissues in comparison with the nontumor tissues. Functionally, in vitro experiments show that Siglec‐15 promotes the migration of hepatoma cells. Furthermore, the data demonstrated an interaction between Siglec‐15 and CD44, a transmembrane glycoprotein that mediates tumor progression and metastasis. In addition, we show that CD44 is modified by α2,6‐linked sialic acids on N‐glycans in hepatoma cells and that CD44 sialylation affects its interaction with Siglec‐15. Removal of the sialic acid residues from CD44 resulted in suppressed interaction between Siglec‐15 and CD44. We further demonstrate that Siglec‐15 interacts and promotes the stability of CD44 by preventing its lysosomal‐mediated degradation. Taken together, our findings demonstrate that Siglec‐15 promotes the migration of hepatoma cells by regulating the CD44 protein stability.

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The quiescent/slow‐cycling state preserves the self‐renewal capacity of cancer stem cells (CSCs) and leads to the therapy resistance of CSCs. The mechanisms maintaining CSCs quiescence remain largely unknown. Here, it is demonstrated that lower expression of MAN1A1 in glioma stem cell (GSC) resulted in the formation of high‐mannose type N‐glycan on CD133. Furthermore, the high‐mannose type N‐glycan of CD133 is necessary for its interaction with DNMT1. Activation of p21 and p27 by the CD133–DNMT1 interaction maintains the slow‐cycling state of GSC, and promotes chemotherapy resistance and tumorigenesis of GSCs. Elimination of the CD133–DNMT1 interaction by a cell‐penetrating peptide or MAN1A1 overexpression inhibits the tumorigenesis of GSCs and increases the sensitivity of GSCs to temozolomide. Analysis of glioma samples reveals that the levels of high‐mannose type N‐glycan are correlated with glioma recurrence. Collectively, the high mannose CD133–DNMT1 interaction maintains the slow‐cycling state and tumorigenic potential of GSC, providing a potential strategy to eliminate quiescent GSCs.