Lead is a ubiquitous environmental chemical with various toxic damage to human body. This investigation aimed to explore the intervention effect of human umbilical cord mesenchymal stem cells derived exosomes (HUC-MSC-exo) on the neurotoxicity of lead and the relevant mechanism. Differential gradient ultracentrifugation was adopted to isolate HUC-MSC-exo. Nanoparticle tracking assay (NTA), Transmission electron microscope (TEM) technology and exosomal specific biomarkers CD9, CD63 and CD81 were adopted for exosomal characterization. Human neuroblastoma cell (SH-SY5Y) was used as the recipient cell. Confocal laser scanning microscope analysis was conducted to confirm the intake of HUC-MSC-exo by SH-SY5Y cells. Cell migration ability, apoptosis, IL-6, IL-1β and TNF-α were analyzed. The role of miR-26a-5p/PTEN axis was assessed. The result showed that the exposure of SH-SY5Y cells to lead activated the miR-26a-5p/PTEN pathway by down-regulating miR-26a-5p and up-regulating PTEN expression, which was related to the significantly decreased cell migration and increased apoptosis, as well as significantly enhanced levels of inflammatory cytokine as compared with the control. While HUC-MSC-exo could significantly alleviate the cytotoxicity, apoptosis and inflammatory effects induced by lead on SH-SY5Y cells via partially restoring miR-26a-5p/PTEN pathway. Herein, we conclude that HUC-MSC-exo can alleviate lead-induced toxic effects on SH-SY5Y cells partially through miR-26a-5p/PTEN pathway.
Objective Flap endonuclease 1 (FEN1) has been confirmed to involve the drug resistance of multiple cancers including breast cancer.However, the effect of miRNA-mediated FEN1 on breast cancer cell resistance is still ambiguous and needs further research. Methods Firstly, we used GEPIA2 to predict the FEN1 expression in breast cancer. Next, we used quantitative real-time polymerasechain reaction (qRT-PCR) and western blot to evaluate the FEN1 level of cells. After parental cells or MDA-MB-231-paclitaxel(PTX) cells being transfected with or without siFEN1, the apoptosis, migration, and protein levels of FEN1, Bcl-2, and resistance-relatedgenes were examined by flow cytometry, wound healing assay, and western blot, respectively. Then, the putative miRNA targetingFEN1 was predicted using StarBase V3.0, and further confirmed by qRT-PCR. The targeted binding of FEN1 to miR-26a-5p was detectedby dual-luciferase reporter assay. After parental cells or MDA-MB-231-PTX cells being transfected with or without miR-26a-5pmimic, the apoptosis, migration, and protein levels of FEN1, Bcl-2, and resistance-related genes were tested again. Results FEN1 expression was enhanced in breast cancer and MDA-MB-231-PTX cells. The combined application of FEN1 knockdown and PTXenhanced apoptosis in MDA-MB-231-PTX cells but suppressed cell migration and expressions of FEN1, Bcl-2, and resistance-relatedgenes. Then, we confirmed that FEN1 was targeted by miR-26a-5p. The combined application of miR-26a-5p mimic and PTX largelyfacilitated apoptosis in MDA-MB-231-PTX cells but restrained cell migration and expressions of FEN1, Bcl-2, and resistance-relatedgenes. Conclusion MiR-26a-5p contributes to the sensitivity of breast cancer cells to paclitaxel via restraining FEN1.
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