Fig 2: Restoration of CALD1 reverses the effects of miR-1278 on GC cell growth and the MAPK signaling cascade. (a) Western blotting analysis of the CALD1 protein expression in CALD1-overexpressed AGS and GTL-16 cells transfected with an miR-1278 mimic. (b) Cell viability in CALD1-overexpressed AGS and miR-1278 mimic-transfected GTL-16 cells was analyzed using a CCK-8 kit. (c and d) Cell migration and invasion in CALD1-overexpressed AGS and miR-1278 mimic-transfected GTL-16 cells were analyzed using a Transwell assay. (e) The levels of migration-related proteins (E-cadherin, N-cadherin, and Snail) in CALD1-overexpressed AGS and miR-1278 mimic-transfected GTL-16 cells were analyzed using western blotting. (f) The levels of the MAPK signaling pathway-related proteins (Ras, P38, p-P38, ERK1/2, and p-ERK1/2) in CALD1-overexpressed AGS and miR-1278 mimic-transfected GTL-16 cells were analyzed using western blotting (compared with the empty vector group, **P < 0.001; compared with the mimic-NC group, ++ P < 0.001; compared with the CALD1-OE + mimic group, ^^ P < 0.001).

Fig 3: miR-1278 is downregulated in GC, whereas miR-1278 overexpression inhibits the viability and migration of GC cells and suppresses the MAPK signaling pathway in vitro. (a) qRT-PCR analysis of miR-1278 levels in GC tissues and paracancerous tissues (**P < 0.001). (b) The levels of miR-1278 in GC cells (HGC-27, AGS, GTL-16) and gastric epithelium immortalized cells (GES-1) were determined using qRT-PCR (compared with the GES-1 group, *P < 0.05 and **P < 0.001). (c) Transfection efficiency of the miR-1278 mimic and mimic-NC in GC cells, measured using qRT-PCR (compared with the mimic-NC group, **P < 0.001). (d) The effects of miR-1278 overexpression on GC cell viability were analyzed using a CCK-8 kit (compared with the mimic-NC group, **P < 0.001). (e and f) The effects of miR-1278 overexpression on the migration and invasion of GC cells were analyzed using a Transwell assay (compared with the mimic-NC group, **P < 0.001). (g) The regulation of migration-related protein markers (E-cadherin, N-cadherin, and Snail) by miR-1278 overexpression was analyzed using western blotting. (h) The regulation of MAPK signaling pathway-related protein levels (Ras, P38, p-P38, ERK1/2, and p-ERK1/2) by miR-1278 overexpression was analyzed using western blotting (compared with the mimic-NC group, **P < 0.001).