LncRNA Xist Promotes Proliferation and Migration of Rat BMSC by Regulating CXCR4 Expression / 中山大学学报(医学科学版)

@#【Objective】To explore the role of lncRNA Xist in proliferation and migration of rat bone marrow mesenchymal stem cells（BMSC）and its possible mechanism.【Methods】BMSC were isolated，cultured and identified from the femur and tibia of 3 weeks old SD female rats in vitro. SiRNAs was designed and screened to acquire a high silencing efficiency siRNA. Lipo2000 was used to transfected si- Xist and si- NC into BMSC of the experimental group（si- Xist group）and the control group（si-NC group）. BMSC proliferation capacity was determined by CCK-8 assay. The transverse and longitudinal mobility of BMSC were measured by wound healing assay and transwell migration assays. QPCR was performed to verify the silencing efficiency of lncRNA Xist and detect the expression levels of SDF- 1 and CXCR4 mRNA. Western blot was used to quantify the expression of CXCR4 protein.【Results】The P3 generation BMSC shows shuttle- like or whirlpool-like，and flow cytometry showed CD11b（-），CD34（-），CD45（-），CD44（+），CD90（+），CD105（+）. When siRNAs were used to interfere with the expression of lncRNA Xist in BMSC ，the silencing efficiency of three siRNAs was 67.92% ，68.72% and 98.32% ，respectively. CCK- 8 assay showed that the OD450 value of si- Xist group decreased compared with si-NC group at 24 h and 48 h（P < 0.001，P < 0.01，respectively）and had no statistical difference at 12 h（P > 0.05）. Wound healing assay showed that the wound healing percentage of si-Xist group was lower than that of si-NC group（P < 0.05）；and the transwell migration assay showed that，compared with si- NC group，the cells that migrated through the polycarbonate membrane were obviously decreased at 6 h（P < 0.001）. QPCR experiment showed that CXCR4 expression in si-Xist group was lower than that in si-NC group at mRNA level（P < 0.05），while SDF-1 expression showed no significant statistical difference（P > 0.05）. Western blotting confirmed that CXCR4 expression in si- Xist group was lower than that in si-NC group（P < 0.05）.【Conclusions】LncRNA Xist promotes proliferation and migration of rat BMSC by regulating CXCR4 expression.

Long non-coding RNA XIST modulates cisplatin resistance by altering PDCD4 and Fas-Lexpressions in human nasopharyngeal carcinoma HNE1 cells / 南方医科大学学报

OBJECTIVE@#To explore the role of long non-coding RNA (lncRNA) X inactive specific transcript (XIST) in modulating cisplatin (DDP) resistance of human nasopharyngeal carcinoma cells and investigate the possible mechanism.@*METHODS@#Realtime PCR was performed to detect the expression of XIST in cisplatin-resistant human nasopharyngeal carcinoma cell line HNE1/DDP. The effects of up-regulation and down-regulation of XIST on DDP resistance, proliferation and apoptosis of HNE1/ DDP cells were assessed using MTT assay, EdU assay and flow cytometry. Western blotting was used to detect the changes in the expressions of programmed cell death 4 (PDCD4) and Fas ligand (Fas-L) proteins in the cells in response to up-regulation or down-regulation of XIST.@*RESULTS@#The expression of XIST was significantly up-regulated in HNE1/DDP cells in comparison with HNE1 cells (0.57±0.06 0.1±0.02, < 0.05). Down-regulation of XIST significantly decreased while up-regulation of XIST obviously increased DDP resistance of HNE1/DDP cells ( < 0.05). Down-regulation of XIST significantly reduced the proliferation (6.17 ± 1.93 16.59 ± 4.86, < 0.05) and enhanced apoptosis [(18.04 ± 4.72)% (4.22 ± 1.65)%, < 0.05], while upregulating XIST enhanced the proliferation (25.40±7.21 13.16±3.95, < 0.05) and inhibited apoptosis [(2.82±0.88)% (6.46± 1.75)%, < 0.05] in HNE1/DDP cells. Down-regulation of XIST significantly increased the protein expressions of PDCD4 and Fas-L ( < 0.05) in HNE1/DDP cells, and up-regulation of XIST resulted in reverse changes in PDCD4 and Fas-L expressions ( < 0.05).@*CONCLUSIONS@#XIST is up-regulated in HNE1/DDP cells, and down-regulation and up-regulation of XIST expression reduce and increase DDP resistance of the cells, respectively, possibly as a result of changes in the expressions of PDCD4 and Fas-L.

Upregulation of long non-coding RNA XIST has anticancer effects on epithelial ovarian cancer cells through inverse downregulation of hsa-miR-214-3p / 부인종양

OBJECTIVE: The present study is to evaluate the biological functions of long non-coding RNA (lncRNA), X-inactive specific transcript, X-inactive specific transcript (XIST) in human epithelial ovarian cancer (EOC). METHODS: XIST was upregulated in EOC cell lines, CAOV3 and OVCAR3 cells by lentiviral transduction. The effects of XIST overexpression on cancer cell proliferation, invasion, chemosensitivity and in vivo tumor growth were investigated, respectively. Possible sponging interaction between XIST and human microRNA hsa-miR-214-3p was further evaluated. Furthermore, hsa-miR-214-3p was overexpressed in XIST-upregulated CAOV3 and OVCAR3 cells to evaluate its effect on XIST-mediated EOC regulation. RESULTS: Lentivirus-mediated XIST upregulation had significant anticancer effects in CAOV3 and OVCAR3 cells by suppressing cancer cell proliferation, invasion, increasing cisplatin chemosensitivity and inhibiting in vivo tumor growth. Hsa-miR-214-3p was confirmed to directly bind XIST, and inversely downregulated in XIST-upregulated EOC cells. In EOC cells with XIST upregulation, secondary lentiviral transduction successfully upregulated hsa-miR-214-3p expression. Subsequently, hsa-miR-214-3p upregulation functionally reversed the anticancer effects of XIST-upregulation in EOC. CONCLUSION: Upregulation of lncRNA XIST may suppress EOC development, possibly through sponging effect to induce hsa-miR-214-3p downregulation.

New Advances in Human X Chromosome Status from a Developmental and Stem Cell Biology

Recent advances in stem cell biology have dramatically increased the understanding of molecular and cellular mechanism of pluripotency and cell fate determination. Additionally, pluripotent stem cells (PSCs), including embryonic stem cells and induced pluripotent stem cells, arose as essential resources for disease modeling and cellular therapeutics. Despite these advancements, the epigenetic dysregulation in pluripotency such as the imprinting status, and X chromosome dosage compensation, and its consequences on future utility of PSCs yet remain unresolved. In this review, we will focus on the X chromosome regulation in human PSCs (hPSCs). We will introduce the previous findings in the dosage compensation process on mouse model, and make comparison with those of human systems. Particularly, the X chromosome activation status of human preimplantation embryos, and the regulation of the active X chromosome by human specific lincRNA, X Active Coating Transcript (XACT), will be discussed. We will also discuss the recent findings on higher order X chromosome architecture, and abnormal X chromosome status in hPSCs.