Fig. 4
TCF4 promotes tumorigenesis and inhibits ER stress in colorectal cancer. A-C EdU staining, Tranwell, and Wound healing assays showing proliferation, invasion, and migration of RKO or LoVo cells stably expressing Mock, TCF4, sh-Scb, or sh-TCF4 #1 (n = 3). Scale bars of B: 50 μm. D Flowchart of xenografts by subcutaneous injection of RKO cells stably transfected with Mock, TCF4, sh-Scb, or sh-TCF4 #1 into the dorsal flanks of nude mice. E–F Representative fluorescence and tumor images (E) and tumor growth curve of xenografts (F) by subcutaneous injection of RKO cells stably transfected with Mock, TCF4, sh-Scb, or sh-TCF4 #1 into the dorsal flanks of nude mice (n = 5). G Western blot assay showing the expression of TCF4, IRE1α, p-IRE1α, PERK, p-PERK, and CHOP in RKO or LoVo cells stably expressing Mock, TCF4, sh-Scb, or sh-TCF4 #1 (n = 3). Normalized to β-actin. H The quantitative histogram for the fluorescence images of ATF4 and CHOP in RKO or LoVo cells stably expressing Mock, TCF4, sh-Scb, or sh-TCF4 #1. I Representative fluorescence images and the quantitative histogram of ER tracker-red in RKO or LoVo cells stably expressing Mock, TCF4, sh-Scb, or sh-TCF4 #1 (n = 3). Scale bars: 10 μm. J Flow cytometry analysis of intracellular ROS levels in RKO or LoVo cells stably expressing Mock, TCF4, sh-Scb, or sh-TCF4 #1 (n = 3). K The calcium indicator Fluo-3 AM detects intracellular Ca2+ levels in RKO or LoVo cells stably expressing Mock, TCF4, sh-Scb, or sh-TCF4 #1 (n = 6). The statistical results were presented as mean ± SD. Student’s t-test compared the difference in A-B and H–K, and two-way ANOVA compared the difference in C and F. * P < 0.05, ** P < 0.01 compared with Mock; # P < 0.05, ## P < 0.01 compared with sh-Scb. IRE1α: endoplasmic reticulum to nucleus signaling 1-alpha; p-IRE1α: phosphor-IRE1α; PERK: eukaryotic translation initiation factor 2 alpha kinase 3, EIF2AK3; p-PERK: phosphor-PERK; ROS: reactive oxygen species; Ca2+: calcium