Figure 5. Methylation of EGFR increases tumorigenesis in orthotopic colorectal cancer mouse model and correlates with poorer clinical outcomes of colorectal cancer patients.
(A) In vivo orthotopic colon tumor growth of HT29 cells expressing vector control, WT, or R198/200K mutant (Mut) EGFR with or without knockdown of PRMT1 (n = 5 per group). Data are expressed as mean ± SD. Top: Representative tumors from each group in the fourth week after inoculation. (B) Immunochemistry staining of GEO cells expressing WT, R198/200K EGFR, or vector control by me-R198/200 Ab competed without or with synthesized unmodified R198/200 EGFR peptide, asymmetric dimethylated histone H4R3 peptide, or asymmetric dimethylated R198/200 EGFR peptide. Scale bars: 50 μm. (C) Immunochemistry staining of colon cancer tissue by EGFR methylation antibody competed without or with indicated peptide. Scale bars: 25 μm. Images shown are representative of 3 independent experiments. (D) Kaplan-Meier plot of overall survival of 215 colorectal cancer cases with low or high methyl-EGFR level detected by me-R198/200 Ab. (E) Kaplan-Meier plot of recurrence rate of 120 colorectal cancer cases with low or high methyl-EGFR level detected by me-R198/200 Ab. P < 0.05 using Student’s t-test.