Abstract：Objective: To explore the expression levels of miR-27b and homeobox protein HOXB8 in gastric cancer tissues, and the mechanisms by which they regulate human gastric cancer stem cell-like characteristics. Methods: Collected 30 cases of gastric cancer tissues and corresponding normal tissues adjacent to the cancer in our hospital. The differences in the expression of miR-27b and HOXB8 in tissues was detected with real-time fluorescence quantitative PCR. Bioinformatics tool TargetScan7.2 and dual luciferase reporter gene technology were adopted to predict and verify the targeting relationship between miR-27b and HOXB8. The immunomagnetic bead sorting method was used to separate gastric cancer stem cells from the gastric cancer cell line SGC-7901. MiR-27b mimic and negative control (miR-27b NC) were transfected into gastric cancer stem cells by liposome-mediated method. The expression of miR-27b in gastric cancer stem cells after transfection was detected with real-time fluorescence quantitative PCR, Western blot was adopted to detect HOXB8 protein expression in gastric cancer stem cells after transfection, CCK-8 method was used to detect the activity of gastric cancer stem cells, EdU test was applied to detect the proliferation of gastric cancer stem cells, Cell spheroidization experiment and cell clone formation experiment were conducted to detect the self-renewal ability of gastric cancer stem cells. Results: The expression level of miR-27b in gastric cancer tissues was higher than that of normal tissues adjacent to cancer, while HOXB8 was lower than that of normal tissues adjacent to cancer (P<0.01); miR-27b and HOXB8 3'-UTR have base complementation in specific regions. The relative fluorescence of cells co-transfected with miR-27b mimic and WT-HOXB8 3’-UTR recombinant plasmid was lower than that of cells co-transfected with miR-27b NC and WT-HOXB8 3’-UTR recombinant plasmid (P<0.01). After sorting, high-purity CD44+ labeled gastric cancer stem cells were obtained, and miR-27b mimic was successfully transfected into gastric cancer stem cells. Compared with the blank control group, miR-27b expression in gastric cancer stem cells of miR-27b mimic group increased (P<0.01), HOXB8 protein expression decreased (P<0.01), cell viability decreased (P<0.01), EdU-labeled positive cells decreased (P<0.01), the number of cells into spheres is less, the size of spheres becomes smaller, and the number of cell clone formation decreased (P<0.01). Conclusion: The expression of miR-27b is decreased and the expression of HOXB8 is increased in gastric cancer tissues. MiR-27b regulates the proliferation and self-renewal ability of gastric cancer stem-like cells by targeting to silence the expression of HOXB8.
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2021, Vol. 27 
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