Zhongguo aizheng zazhi (Dec 2022)
Glioma stem cell-derived exosomal lncRNA HOXA-AS2 promoted proliferation, migration, invasion and stemness in glioma
Abstract
Background and purpose: Exosomes are important messengers that mediate the crosstalk between cancer cells and recipient cells in the tumor microenvironment; however, the role of extracellular exosomal long non-coding RNA (lncRNA) in the cell-cell communications of glioma stem cells (GSCs) and glioma cells remains unclear. This study investigated the effects of exosome-derived lncRNAs on proliferation, migration, invasion and stemness in glioma. Methods: The datasets containing low-grade glioma (LGG) and high-grade glioma (HGG) lncRNA expression data were downloaded from the Chinese Glioma Genome Atlas (CGGA) and the Cancer Genome Atlas (TCGA) databases. Differentially expressed lncRNA (DelncRNA) between LGG and HGG tissues was identified, and the relationship between HOXA-AS2 levels and overall survival (OS) of glioma patients was analyzed. GSCs were isolated from human glioma cell line SHG44, and CD133+ enriched cells were detected by flow cytometry. The expression levels of stem cell-related proteins (CD133, SOX2 and OCT4) were detected by Western blot. Exosomes derived from SHG44-GSCs were extracted and identified, and labeled with PKH26 cell membrane dye. Then SHG44-GSCs transfected with Cy3-labeled HOXA-AS2 were indirectly co-cultured with SHG44 cells. The levels of HOXA-AS2 in SHG44-GSCs and SHG44-GSC-derived exosomes were detected by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR). The plVX-IRES-PURO HOXA-AS2 lentivirus plasmid and lentivirus shRNA containing targeting HOXA-AS2 plasmid were used for lentivirus transfection. The effect of HOXA-AS2 derived from SHG44-GSC on the proliferation and invasion of SHG44 cells was detected by cell counting kit-8 (CCK-8) and transwell assays. Results:HOXA-AS2 was highly expressed in gliomas, and was associated with worse OS in patients (P<0.01). The proportion of CD133+ cells were significantly higher in SHG44-GSC than in SHG44 cells (P<0.000 1). The expression levels of stem cell related proteins (CD133, SOX2 and OCT4) in SHG44-GSC cells were significantly higher compared with parental SHG44 cells (P<0.000 1). HOXA-AS2 level was significantly increased in SHG44-GSC cells (P<0.000 1). PKH26-labeled exosomes were absorbed by SHG44 cells, and Cy3-labeled HOXA-AS2 could be observed in SHG44 cells. HOXA-AS2 levels were significantly increased in HOXA-AS2 OE transfected SHG44-GSCs cells (SHG44-GSC/HOXA-AS2 OE) and SHG44-GSC/HOXA-AS2 OE-derived exosomes (SHG44-GSC/HOXA-AS2 OE-Exo) (P<0.01). In addition, HOXA-AS2 levels were significantly increased in SHG44 cells co-cultured with SHG44-GSC/HOXA-AS2 OE cells (P<0.01). HOXA-AS2 could be transferred from SHG44-GSC to SHG44 cells through exosomes. Functionally, SHG44-GSC/HOXA-AS2 OE-Exo significantly promoted the proliferation, migration and invasion of SHG44 cells. Conclusion: Exosomal HOXA-AS2 derived from SHG44-GSCs significantly promoted glioma cell proliferation, migration, invasion and stemness, suggesting that HOXA-AS2 may be a potential therapeutic target for glioma.
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