Expression of stomach cancer-associated transcript 16 in gastric cancer tissues and its effects on gastric cancer biological behavior

Abstract

Objective To study the expression of long non-coding RNA (LncRNA) stomach cancer-associated transcript 16 (STCAT16) in gastric cancer tissues and its effects on the proliferation, migration and invasion of gastric cancer cells. Methods The different expression of STCAT16 in 32 cases of gastric carcinoma and corresponding adjacent tissues was detected by real-time fluorescence quantitative polymerase chain reaction (PCR). The STCAT16 overexpression plasmid and empty vector was separately transfected gastric cancer cell line AGS with low expression of STCAT16. The cell proliferation of empty vector group, non-transfection group and STCAT16 analogue transfection group was evaluated by cell counting kit-8 (CCK-8) assay at 0, 24, 48, 72 and 96 hours after transfection. The colony forming ability was tested by colony formation assay. The cell invasion ability was measured by Transwell chamber assay and migration ability was tested by scratch-wound assay. The effects of STCAT16 on tumorigenicity in vivo were verified by tumorigenicity experiments in nude mice. T-test and one-way analysis of variance were performed for data analysis. Repeated measures analysis of variance was used to compare the repeated measured data among groups. Chi square test and Fisher exact probability method were used for comparison of counting data. Results The expression of STCAT16 in gastric cancer tissues was low (0.87±0.19), while it was high in corresponding adjacent tissues (2.32±0.37), and the difference was statistically significant (t=-20.859, P<0.05). The expression of STCAT16 of STCAT16 analogue transfection group was higher than that of empty vector group (3.43±0.25 vs 1.00±0.06), and the difference was statistically significant (t=-16.795, P<0.05). Compared to empty vector group and non-transfection group, the cell proliferation decreased in STCAT16 analogue transfection group at 72 and 96 hours after transfection (1.41±0.07, 1.42±0.08, 1.03±0.09, and 1.72±0.11, 1.78±0.14, 1.24±0.08, respectively), and the differences were statistically significant (t=15.043, 5.358, 12.193 and 8.109, all P<0.05). The results of colony formation assay indicated that the colony forming ability of gastric cells in STCAT16 analogue transfection group was lower than that in empty vector group (97.3±9.1 vs 185.0±20.1) and non-transfection group (97.3±9.1 vs 138.0±11.1), and the differences were statistically significant (t=11.634 and 4.417, both P<0.05). The results of Transwell assay showed that the number of AGS cells passing through the membrane of STCAT16 analogue transfection group was significantly less than those of empty vector group and non-transfection group (151.0±28.1 vs 228.0±38.2 and 151.0±28.1 vs 199.3±17.9), and the differences were statistically significant (t=4.823 and 4.747, both P<0.05). After transfection for 48 hours and 72 hours, the scratch-wound repair rate of STCAT16 analogue transfection group decreased, compared with those of empty vector group and non-transfection group ((52.67±6.11)%, (53.33±5.51)%, (42.67±4.72)%, and (90.67±2.51)%, (90.60±5.41)%, (69.67±1.52)%, respectively), and the differences were statistically significant (t=5.773, 5.955, 21.000 and 5.881, all P<0.05). The results of tumorigenicity in nude mice showed that compared with those of empty vector group, the tumor size of STCAT16 analogue transfection group was smaller at one-, two-, three- and four-week ((0.42±0.10) cm3 vs (0.16±0.05) cm3, (0.66±0.13) cm3 vs (0.34±0.05) cm3, (1.25±0.22) cm3 vs (0.54±0.13) cm3, (2.54±0.46) cm3 vs (0.78±0.41) cm3)), and the differences were statistically significant (t=3.175, 4.190, 7.996 and 9.705, all P<0.05). Conclusions STCAT16 is lowly expressed in gastric cancer tissues. The proliferation, migration, invasion ability and tumorigenicity in nude mice of gastric cancer cell is inhibited after upregulating the expression of STCAT16. Key words: Stomach neoplasms; STCAT16; Long non-coding RNA; Cell proliferation; Cell movement