[摘 要] 目的：探索甲硫氨酸腺苷转移酶2（MAT2A）对食管鳞状细胞癌（ESCC）细胞的作用，以及MAT2A抑制剂PF9366对 ESCC细胞的抑制作用及其分子机制。方法：选用人ESCC细胞KYSE450、KYSE510、KYSE180和KYSE410及正常食管上皮细 胞（NEEC），通过 ELISA 实验验证 S-腺苷甲硫氨酸（SAM）在细胞中的产生情况。分别用 0、5、10 和 25 μmol/L PF9366 处理 KYSE450、KYSE510细胞，通过ELISA实验、MTS实验、平板克隆形成实验检测PF9366对ESCC细胞甲硫氨酸（MET）活性和细 胞增殖的抑制效果，采用RNA-seq实验观察PF9366对KYSE450细胞下游促癌信号通路的影响。构建KYSE450、KYSE510细胞 移植瘤小鼠模型，观察PF9366对荷瘤小鼠移植瘤生长的影响。结果：ESCC细胞中的MET活性显著高于NEEC（均P < 0.01）。 使用PF9366后，KYSE450、KYSE510细胞SAM活性均显著降低（均P < 0.01），细胞的增殖能力显著降低（均P < 0.01），其抑制作 用呈现出明显的剂量依赖性（均P < 0.05）。RNA-seq分析表明，PF9366处理后的ESCC细胞中，有20个与肿瘤发生和发展相关的 信号通路被下调。荷瘤小鼠实验表明，PF9366能显著抑制ESCC细胞小鼠移植瘤的生长（均P < 0.000 1）。结论：MAT2A抑制剂 PF9366能抑制ESCC细胞中SAM的产生、抑制细胞增殖并激活下游关键促癌信号网络，提示MET代谢关键酶MAT2A是治疗 ESCC的潜在靶点。

[Abstract] Objective: To investigate the role of methionine adenosyltransferase 2 (MAT2A) in esophageal squamous cell carcinoma (ESCC) and evaluate the inhibitory effects of MAT2A inhibitor PF9366 on ESCC cells and its underlying molecular mechanisms. Methods: Human ESCC cell lines (KYSE450, KYSE510, KYSE180, and KYSE410) and normal esophageal epithelial cells (NEECs) were used in this study. S-adenosylmethionine (SAM) production in these cells was verified by ELISA assay. KYSE450 and KYSE510 cells were treated with various concentrations of PF9366 (0, 5, 10, and 25 μmol/L). The inhibitory effects of PF9366 on methionine (MET) activity and proliferation of ESCC cells were assessed using ELISA, MTS assay, and plate cloning formation assay. RNA-seq was performed to observe the effects of PF9366 on downstream oncogenic signaling pathways in KYSE450 cells. KYSE450 and KYSE510 cell xenograft models were constructed in mice to observe the effects of PF9366 on tumor growth in vivo. Results: MET activity in ESCC cells was significantly higher than that in NEECs (P < 0.01). Following PF9366 treatment, SAM activity and cellular proliferation in KYSE450 and KYSE510 cells were significantly inhibited (all P < 0.01), with a clear dose-dependent inhibitory effect (all P < 0.05). RNA-seq analysis revealed that 20 signaling pathways associated with carcinogenesis and progression were downregulated in PF9366-treated ESCC cells. In vivo xenograft experiments demonstrated that PF9366 treatment significantly inhibited the growth of ESCC cell-derived tumors in mice (all P < 0.0001). Conclusion: MAT2A inhibitor PF9366 inhibits SAM production in ESCC cells, suppresses cell proliferation, and activates key downstream oncogenic signaling networks, suggesting that MAT2A, a key enzyme in methionine metabolism, is a potential therapeutic target for ESCC.

国家自然科学基金（No. 81972243）