Figure 8.

CXCR2 promotes gastric epithelial senescence through p53–p21 signaling. (A and B) SA-β-gal and BrdU staining of AGS cells cotransfected with lentiviruses encoding CXCR2 and small interfering (si)RNA targeting TP53 mRNA for 24 hours, followed by radiation (5 Gy, means ± SD, unpaired t test). Staining was performed 5 days later. Scale bar: 50 μm. Data are representative of 3 independent experiments. Unpaired t test. (B) Representative Western blot images of p53 and p21 under this condition are shown. (C) SA-β-gal staining analysis of HGC27 cells transfected with lentiviruses encoding CXCR2. Cells were stained 5 days after exposure to 5 Gy X-ray. Scale bar: 50 μm. Means ± SD. Unpaired t test. (D) Plate colony formation assay of HGC27 cells transfected with lentiviruses encoding CXCR2. Only clones with a parameter greater than 1 mm were counted. (C) SA-β-gal staining and (D) colony formation were repeated twice independently. (E) Western blot analysis of several key proteins in proliferation-associated pathways in HGC27, KATO III, and AGS cells transfected with lentiviruses encoding CXCR2. All Western blot results shown are representative samples from 3 independent experiments. (F) Quick scores of CXCR2 and p21 in precancerous lesions from the 40 patients as determined by IHC staining. CXCR2 and p21 staining were performed in adjacent slices. Correlations were analyzed by the Spearman test. Left: Representative images are shown. (G) p21 expression in human precancerous lesions as detected by IHC (samples from 20 patients diagnosed with CG, AG, IM, and DP). Scale bar: 100 μm. Plot: median. Mann–Whitney test. All histology images were taken from the antrum. ∗∗P < .01. ∗∗∗P < .001. ∗∗∗∗P < .0001. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; NC, negative control.