Objective:To explore the effects of miR-451 on glycolysis and apoptosis of breast cancer cells by regulating the Rho/ROCK1 pathway.Methods:Breast cancer MCF7 cells were divided into breast cancer cells (BC) group, breast cancer cells + miR-451-NC (MN) group, breast cancer cells + miR-451 inhibitor (MI) group, breast cancer cells + miR-451 mimic (MM) group, breast cancer cells + lysophosphatidic acid (BL) group, breast cancer cells + fasudil (BF) group, and breast cancer cells + miR-451 mimic + fasudil (MF) group. Glucose uptake detection kit and lactate detection kit were used to detect cell glycolysis, DAPI staining was used to detect cell apoptosis, Western blotting was used to detect Rho/ROCK1 pathway protein expression, and double luciferase reporting assay was used to confirm the interaction between miR-451 and Rho/ROCK1.Results:The glucose intake of cells in the BC group, MN group, MI group and MM group were (14.22±2.36) ×10 5 mg/h, (14.20±2.37) ×10 5 mg/h, (21.55±2.43) ×10 5 mg/h, (6.19±1.34) ×10 5 mg/h ( F=5.30, P<0.001), respectively, and lactic acid production were (1.52±0.21) ×10 5 μg/h, (1.53±0.22) ×10 5 μg/h, (2.05±0.32) ×10 5 μg/h, (0.54±0.12) ×10 5 μg/h ( F=3.28, P=0.008), respectively. The apoptosis rates were (10.13±1.35) %, (10.16±1.37) %, (5.36±1.24) %, (28.47±2.56) % ( F=6.36, P<0.001), respectively. The expressions of Rho protein were 2.31±0.46, 2.32±0.41, 2.95±0.35, 1.05±0.25 ( F=2.86, P=0.017), respectively. The expressions of ROCK1 protein were 2.51±0.41, 2.52±0.42, 3.05±0.33, 1.15±0.13 ( F=2.43, P=0.035), and there were statistically significant differences between the MN and MI groups, MN and MM groups, MI and MM groups (all P<0.05). The glucose intake in the BC group, BL group and BF group were (14.22±2.36) ×10 5 mg/h, (21.54±2.40) ×10 5 mg/h, (6.20±1.35) ×10 5 mg/h ( F=5.33, P<0.001), respectively. Lactic acid production were (1.52±0.21) ×10 5 μg/h, (2.01±0.30) ×10 5 μg/h, (0.55±0.12) ×10 5 μg/h ( F=3.28, P=0.008), respectively. The apoptosis rates were (10.13±1.35) %, (5.34±1.22) %, (28.44±2.54) % ( F=6.45, P<0.001). The expressions of Rho protein were 2.31±0.46, 2.94±0.45, 1.01±0.24 ( F=2.40, P=0.037), respectively, and the expressions of ROCK1 protein were 2.51±0.41, 3.08±0.42 and 1.13±0.12, respectively ( F=2.38, P=0.039). The pairwise comparisons among the three groups were statistically significant (all P<0.05). In the MF group, glucose intake was (3.21±0.89) ×10 5 mg/h, lactic acid production was (0.33±0.04) ×10 5 μg/h, apoptosis rate was (38.01±2.87) %, Rho protein expression was 0.55±0.14, and ROCK1 protein expression was 0.51±0.10. There were statistically significant differences among the MM group, BF group and MF group ( F=4.53, P=0.001; F=4.26, P=0.002; F=6.12, P<0.001; F=4.06, P=0.002; F=9.72, P<0.001), and there were statistically significant differences between the MF group and BF group (all P<0.05). Dual luciferase report showed that miR-451 transfection significantly decreased the luciferase activity of ROCK1-3'-UTR-WT (0.59±0.03 vs. 1.01±0.05, t=17.64, P<0.001), but had no significant effect on mutated genes (1.01±0.07 vs. 1.02±0.04, t=0.30, P=0.767) . Conclusion:Overexpression of miR-451 can significantly inhibit glycolysis of breast cancer cells and promote apoptosis of breast cancer cells, the mechanism of which may be related to inhibition of Rho/ROCK1 pathway.

Objective:To investigate the driving effect of prostate cancer associated transcript 4 (PCAT4) on the up-regulation of upregulator of cell proliferation (URGCP) expression in breast cancer progression through sponging miR-508-5p.Methods:The microarray data of lncRNA and miRNA with differential expression in breast cancer tissue were analyzed by Cancer Genome Atlas. The expression of PCAT4 in breast cancer was evaluated by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation was measured by MTT and colony formation, cell apoptosis was analyzed by TUNEL, and cell migration and invasion were analyzed by Transwell. The correlation between PCAT4 and miR-508-5p, and miR-508-5p and URGCP was analyzed by RNA pull-down and double luciferase assay. Tumor xenograft studies were performed to analyze the correlation between PCAT4/miR-508-5p/URGCP axis and breast cancer cell growth in vivo. Measurement data were expressed as mean ± standard deviation ( ± s). T-test was used for comparison between two groups, and one-way analysis of variance was used for comparison between multiple groups. The correlation between PCAT4 and URGCP and miR-508-5p expression was evaluated by Pearson correlation analysis. Results:The expression level of PCAT4 was up-regulated in breast cancer tissues and cells. Knockout of PCAT4 inhibited cell proliferation and metastasis and promoted cell apoptosis. miR-508-5p was the target of PCAT4 and was negatively correlated with PCAT4. Overexpression of miR-508-5p in breast cancer can inhibit cell growth, migration and invasion, and promote cell apoptosis. URGCP is the target of miR-508-5p and induces progression of breast cancer. Tumor xenograft studies showed that PCAT4 drives breast cancer progression by affecting miR-508-5p/URGCP.Conclusion:The expression of PCAT4 is up-regulated in breast cancer tissues and cells, and PCAT4 can act as a molecular sponge of miR-508-5p, and significantly promote breast cancer progression by activating URGCP protein expression.