Figure 7.

Ferroptosis plays an important role in papillary thyroid carcinoma. Fat mass and obesity-associated protein (FTO) regulates papillary thyroid carcinoma (PTC) cell ferroptosis by mediating the m6A methylation of SLC7A11. (A) SLC7A11 protein expression was examined by western blot in TPC-1-Lv-FTO, TPC-1-vector, TPC-1, KTC-1-shFTO, KTC-1-scramble, and KTC-1 cell. (B) The mRNA expression of FTO and SLC7A11 in PTC tissue specimens was analyzed by Spearman rank correlation coefficient. (C) Ultrastructure of the mitochondria in TPC-1-Lv-FTO cells as imaged by TEM. Red arrowheads, shrunken mitochondria. Scale bars, 2.0 and 5.0 μm. The cells were ovoid, the cell membrane was intact and continuous, a few pseudopods were visible around, the cytoplasm was not obviously edematous, the nucleus was regular, roughly ovoid, and the chromatin was evenly distributed. The mitochondria were fixed, the matrix density was increased, and the cristae were obviously dilated, showing signs of ferroptosis. The rough endoplasmic reticulum was mildly dilated and locally degranulated. A few autophagic lysosomes were visible intracellularly. (D) NOX4, COX2, ACSL4, GPX4, and FTH as ferroptosis biomarkers were measured in control and TPC-1-Lv-FTO/KTC-1-shFTO cells by western blot. (E) The glutathione (GSH)/oxidized GSH ratio was measured in the indicated PTC cells; *P < 0.05, **P < 0.001. (F) Malondialdehyde (MDA) analysis for the evaluation of levels of oxidative stress. MDA was measured in the indicated PTC cells; *P < 0.05, **P < 0.001. (G) Fe²⁺ was measured in the indicated PTC cells; *P < 0.05, **P < 0.001. (H) GPx was measured in the indicated PTC cells; *P < 0.05, **P < 0.001.