目的：探究在低糖低氧状态下通过磷酸腺苷活化蛋白激酶（AMP-dependent/activated protein kinase，AMPK）通路调控肉碱脂酰转移酶1c（carnitine palmitoyltransferase 1c，CPT1c）的表达对甲状腺乳头状癌B-CPAP细胞增殖及凋亡的作用及其机制。方法：对正常条件和低糖低氧条件下培养的人甲状腺乳头状癌细胞B-CPAP，分别给予AMPK抑制剂Compound C处理，使用Western blotting 检测AMPK、p-AMPK、过氧化物酶体增殖物激活受体α（peroxisome proliferator-activated receptor α，PPARα）、CPT1c 的表达，并利用CCK-8 法及FACS 检测各组细胞的增殖和凋亡情况。合成的PPARα-siRNA 转染B-CPAP 细胞以敲低PPARα，分别在正常和低糖低氧环境下培养，同样检测上述指标，以验证PPARα 对CPT1c 的调控作用。构建人CPT1c 基因启动子荧光素酶报告质粒，利用免疫荧光法观察PPARα 对CPT1c 基因启动子荧光素酶活性的影响。结果：（1）低糖和低氧条件下培养的B-CPAP细胞中，AMPK、p-AMPK、PPARα、CPT1c 表达均显著增加（均P<0.05 或P<0.01），细胞增殖和凋亡率未有明显改变（均P>0.05）；（2）应用AMPK抑制剂Compound C后，低糖低氧组p-AMPK、PPARα、CPT1c 明显降低（P<0.05 或P<0.01），细胞增殖抑制率及凋亡率显著升高（均P<0.01），但升高幅度仍小于单独加抑制剂后高于正常对照的幅度（P<0.05）。（3）PPARα 敲低后，正常条件下培养的肿瘤细胞的AMPK、p-AMPK、PPARα、CPT1c 的表达显著减少（P<0.05 或P<0.01），细胞增殖抑制率及凋亡率均显著升高（均P<0.05）；低糖低氧培养条件下，转染后细胞CPT1c 表达显著降低（P<0.05），细胞增殖抑制率及凋亡率有显著升高（均P<0.05），但升高幅度仍低于转染后高于正常对照的幅度（P<0.05）。（4）转染过表达PPARα 后，空载组双荧光比值与空白组无差异（P>0.05），PPARα 过表达组双荧光比显著增高（P<0.05）。结论：甲状腺乳头状癌B-CPAP细胞在低糖低氧状态下，AMPK通路能够通过上调PPARα 促进CPT1c的表达，从而抑制细胞凋亡和维持细胞增殖能力。

Objective: To investigate the mechanisms of carnitine palmitoyltransferase 1c (CPT1c) expression to affect the proliferation and apoptosis of human thyroid papillary cancer B-CPAP cells through the AMP-dependent/activated protein kinase (AMPK) pathway in the low glucose and hypoxic conditions. Methods: Firstly, human thyroid papillary carcinoma B-CPAP cells were cultured under normal condition or low glucose and hypoxic condition respectively, followed with the treatment of AMPK inhibitor compound C.Western blotting was used to detect the expressions of AMPK, p-AMPK, peroxisome proliferator-activated receptor α (PPARα) and CPT1c; the proliferation and apoptosis were detected by CCK-8 and Flow cytometry, respectively. Then PPARα-siRNA was synthesized and transfected into B-CPAP cells to knock down PPARα, and then the cells were cultured under normal or low glucose and hypoxic condition respectively. Above indicators were also detected to verify the regulation of PPARα on CPT1c. Finally, the human luciferase reporter plasmid containing CPT1c gene promoter was constructed, and the effect of PPARα on the activity of CPT1c promoter luciferase activity was observed by immunofluorescence. Results: The expressions of AMPK, p-AMPK, PPARα and CPT1c were significantly increased in B-CPAP cells under low glucose and hypoxia condition (P<0.05 or P<0.01), while cell proliferation and apoptosis rate did not change significantly (P>0.05). After the treatment of AMPK inhibitor compound C, the expressions of p-AMPK, PPARα and CPT1c in low glucose and hypoxia group were significantly decreased (P<0.05 or P<0.01), the inhibitory rate on cell proliferation and apoptosis rate were significantly increased (P<0.05). However, the change range was smaller than that in the normal culture + compound C group (P<0.05). After PPARα knockdown, the expressions of AMPK, p-AMPK, PPARα and CPT1c in cancer cells cultured under normal conditions were significantly decreased (P<0.05 or P<0.01), and the inhibitory rate on cell proliferation and apoptosis rate were significantly increased (P<0.05). While under low glucose and hypoxia condition, the expression of CPT1c in cells after transfection was significantly decreased (P<0.05), and the inhibition rate on cell proliferation and the apoptosis rate were significantly increased (P<0.05); However, the change range was still lower than that of normal condition group after transfection (P<0.05). After PPARα overexpression,the ratio of fluorescence in the empty vector group was not significantly different from that of the blank group (P>0.05),and the ratio of fluorescence was significantly increased in PPARα over-expression group (P<0.05). Conclusions: AMPK can increase the expression of PPAR α to promote the expression of CPT1c in thyroid cancer B-CPAP cells under low glucose and hypoxia conditions, thereby inhibiting cell apoptosis and maintaining cell proliferation ability.

国家自然基金面上基金资助项目（No. 81372862）