The role and mechanism of long non-coding RNA KCNQ1 overlapping transcript 1 in the proliferation, migration and invasion of hepatocellular carcinoma / 中华消化外科杂志

ABSTRACT

Objective:To explore the role and mechanism of long non-coding RNA KCNQ1 overlapping transcript 1 (LncRNA KCNQ1OT1) in the migration, proliferation and invasion of hepatocellular carcinoma (HCC).Methods:The experimental method was conducted. The expression levels of LncRNA KCNQ1OT1 in HCC tissues and normal liver tissues in the StarBase database were collected. The experimental methods including real-time quantitative PCR, cell transfection, scratch assay, CCK8 assay, Transwell assay, Western blot were used to determine the expression, migration, proliferation, invasion of LncRNA KCNQ1OT1 in HCC cells and its relationship with phosphatidylinositol 3-kinase/phosphorylated AKT Protein (PI3K /p-AKT) signaling pathways. Observation indicators (1) expression of LncRNA KCNQ1OT1 in HCC tissues and normal liver tissues; (2) the migration of HepG2, SMCC-7721 and MHCC-97H HCC cells after LncRNA KCNQ1OT1 gene knockdown; (3) the proliferation and invasion of HepG2, SMCC-7721 and MHCC-97H HCC cells after LncRNA KCNQ1OT1 gene knockdown; (4) effects of LncRNA KCNQ1OT1 gene knockdown on PI3K/p-AKT signaling pathways. Measurement data with normal distribution were expressed as Mean± SD, and comparison between groups was analyzed using the t test. The Kaplan-Meier method was used to calculate survival rates and draw survival curves. Results:(1) Expression of LncRNA KCNQ1OT1 in HCC tissues and normal liver tissues. The expression levels of LncRNA KCNQ1OT1 in 374 HCC tissues and 50 normal liver tissues from StarBase database were 3.320±0.017 and 1.470±0.025, respectively, showing a significant difference ( t=5.24, P<0.05). Results of gene expression profile interactive analysis showed that the 30-month disease-free survival rates of HCC patients with high and low expression levels of LncRNA KCNQ1OT1 were 41% and 55%, respectively, with a significant difference ( χ2=6.209, P<0.05). The relative expression of LncRNA KCNQ1OT1 in HepG2, SMCC-7721and MHCC-97H cells were 1.470±0.042, 3.300±0.032, 4.040±0.031, respectively, versus 1.000±0.022 in normal liver cells (LO2), showing significant differences ( t=17.66, 95.40, 114.20, P<0.05). (2) The migration of HepG2, SMCC-7721 and MHCC-97H HCC cells after LncRNA KCNQ1OT1 gene knockdown. ① Results of cell transfection showed that the relative expression levels of LncRNA KCNQ1OT1 in HepG2, SMCC-7721 and MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 0.350±0.016, 0.310±0.020, 0.380±0.018, respectively, versus 1.000±0.021, 1.000±0.018, 1.000±0.019 in the negative control cells, showing significant differences ( t=23.40, 28.15, 22.32, P<0.05). ② Results of scratch assay showed that the healing rates of HepG2, SMCC-7721, MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 85.0%±1.9%, 75.0%±1.8%, 90.0%±1.7%, respectively, versus 100.0%±2.0%, 95.0%±1.8%, 72.0%±1.7% of the negative control cells, showing significant differences ( t=31.35, 47.36, 38.42, P<0.05). ③ Results of Transwell assay showed that the vertical migration rates of HepG2, SMCC-7721, MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 195±10, 205±12, 85±8, respectively, versus 520±11, 430±7, 405±20 of the negative control cells, showing significant differences between them ( t=922.30, 458.20, 708.40, P<0.05). (3) The proliferation and invasion of HepG2, SMCC-7721 and MHCC-97H HCC cells after LncRNA KCNQ1OT1 gene knockdown. ① Results of CCK8 assay showed that 72-hour optical densities of HepG2, SMCC-7721, MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 1.370±0.018, 1.240±0.016, 1.360±0.020, respectively, versus 0.900±0.023, 1.740±0.032, 1.230±0.025 of the negative control cells, with significant differences ( t=10.79, 12.00, 7.56, P<0.05). ② Results of Transwell assay showed that the invasion numbers of HepG2, SMCC-7721, MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 186±12, 155±7, 75±9, respectively, versus 505±1, 245±8, 300±15 of the negative control cells, showing significant differences ( t=955.90, 163.40, 530.90, P<0.05). (4) Effects of LncRNA KCNQ1OT1 gene knockdown on PI3K/p-AKT signaling pathways. Resluts of Western blot showed that the relative repression levels of PI3K in HepG2, SMCC-7721, MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 0.447±0.009, 0.430±0.012, 0.354±0.006, respectively, versus 0.820±0.017, 0.850±0.012, 0.531±0.001 of the negative control cells, showing significant differences ( t=18.94, 25.72, 27.46, P<0.05). The relative repression levels of p-AKT in HepG2, SMCC-7721, MHCC-97H cells after LncRNA KCNQ1OT1 gene knockdown were 0.343±0.015, 0.410±0.012, 0.579±0.006, respectively, versus 0.546±0.012, 0.620±0.012, 0.830±0.012 of the negative control cells, showing significant differences ( t=10.78, 12.86, 19.02, P<0.05). Conclusions:LncRNA KCNQ1OT1 plays an important role in the occurrence and development of HCC. LncRNA KCNQ1OT1 gene knockdown can inhibit the PI3K/AKT signaling pathways, so it can significantly inhibit the proliferation, migration and invasion of HCC cells.