Fig. 2

Loss of FTO is responsible for the aberrant m6A modifications in HCC. (a) The expression of FTO, ALKBH5, METTL3, and METTL14 were assessed in 120 pairs of HCC tissues (Cohort 1) by qRT-PCR. The expression of FTO, ALKBH5, and METTL14 in tumor samples was significantly lower compared to adjacent nontumor tissues. Statistical analysis was performed using a paired Student’s t-test. (b) Representative histology of FTO IHC staining in peritumor and HCC tissues. FTO predominantly localizes in the cell nucleus. (c) qRT-PCR revealed that the FTO expression in MHCCLM3 and MHCC97H cells, possessing high metastatic potential, was markedly lower compared to HepG2 and MHCC97L cells. Differences were assessed using an unpaired Student’s t-test. (d) Western blot results were consistent with the qRT-PCR findings, showing significantly lower expression levels of FTO in MHCC97H and MHCCLM3 cells compared to HepG2 and MHCC97L cells. Differences were assessed using an unpaired Student’s t-test. (e) There is a clear negative correlation between FTO expression and m6A levels. In the tumor tissue of Patient 1, where FTO expression is nearly absent, m6A is significantly present, while in tumor tissue from Patient 3 with high FTO expression, m6A levels are markedly diminished. (f) HCC patients with low expression levels of FTO have a higher tumor recurrence rate. Herein, exemplifying Patient 5 and 9 with tumor remission and Patient 6 and 8 with tumor recurrence. Data are shown as mean ± S.D. (n = 3). *P<0.05, **P<0.01, and ***P<0.001. Scale bars = 100 μm. HCC, hepatocellular carcinoma