Figure 6. EGFR contributes to 5-FU resistance in colon cancer cells through autophagy. (A) Xenograft tumors formed in nude mice. A total of 5 × 106 cells was subcutaneously injected into nude mice (n=5 for each group). The mice were sacrificed on day 21 after the injection. Tumors were harvested and representative images are shown. (B) and (C) EGFR knockdown promoted the anticancer effect of 5-FU in vivo as demonstrated by reduced tumor volume (B) and tumor weight (C) (n=5). (D) Immunohistochemical staining of Ki-67 in xenograft specimens. (E) Autophagy induction in a xenograft model was decreased by EGFR silencing upon 5-FU treatment. (n=5) (F) Conversion of LC3-I to LC3-II was inhibited by EGFR silencing upon 5-FU treatment (n=5, *P < 0.05 versus control).