Figure 4.

RNF43 influences susceptibility to DNA damage-inducing chemotherapeutics. Representative images showing γH2AX, cleaved caspase 3 (c-caspase 3), and Ki67 detected by immunohistochemistry in xenograft tumors that originated from control MKN45 (shCtrl) and RNF43 knockdown MKN45 (shRNF43) cells after treatment with (A) 5-fluorouracil or (B) cisplatin. Quantification of positive cells per square millimeter is shown. Each dot represents 1 mouse. (C) Viability of gastric organoids from WT or Rnf43^ΔEx8 mice after treatment with 5-fluorouracil (5-FU) or cisplatin. Values were normalized over untreated (N = 3). Spearman correlation between RNF43 mRNA expression levels in human gastric tissue samples (N = 13), and viability of organoids generated from the same tissue samples after treatment with (D) 5-fluorouracil or (E) cisplatin. RNF43 mRNA levels normalized to GAPDH also are shown. (F) AXIN2 and LGR5 mRNA levels in AGS, AGS^D196fs, and MKN45 control and RNF43 knockdown cells. Cycle threshold (C_T)values were normalized to GAPDH and fold change was calculated over control cells (N = 3). Error bars indicate SD. Horizontal lines represent the median values. ∗P ≤ .05, ∗∗P ≤ .01, (C and F) 2-tailed unpaired t test, (A, B, D, and E) Mann–Whitney test. mRNA, messenger RNA.