碳酸酐酶CA9改变胞内pH影响舌癌的化疗

平阳霉素PYM（pingyangmycin）是舌癌最常用的化疗药物之一，而碳酸酐酶（carbonic anhydrase IX precursor, CA9）参与舌癌细胞对PYM的耐受. 有迹象表明,这种耐受的产生与CA9调节胞内pH的功能有关. 本文拟从此现象出发，探讨CA9的胞内pH调节功能对舌癌细胞化疗的影响. 以BCECF AM探针法评估实验细胞胞内pH的变化，并通过对比PYM与CA9抑制剂乙酰唑胺（acetazolamide，Atz）处理Tca8113/PYM细胞、PYM处理的Tca8113细胞及PYM处理的Tca8113/PYM细胞各组细胞中细胞凋亡标记物caspase 3的活化状态，以评估CA9的胞内pH调节功能对PYM诱导舌癌细胞凋亡的影响. Hoechst染色观察表明，经PYM和Atz共处理Tca8113/PYM细胞及经PYM处理24 h后的Tca8113细胞均出现细胞染色质固缩、细胞核呈碎石状和线粒体空泡化现象，表现出细胞凋亡状态，而对照组未见明显变化. Western印迹检测发现,经PYM处理的Tca8113细胞和经PYM与Atz共处理的Tca8113/PYM细胞中凋亡标志物caspase 3均处于活化状态，BCECF-AM探针检测发现,其胞内pH明显降低,对照组不见上述诸状. 由此可见,CA9在胞内pH调节中发挥重要作用，使用Atz抑制CA9活性，将会引起胞内pH值降低，促使PYM耐受舌癌细胞对PYM化疗增敏，可能有助于提高化疗效果.

Carbonic Anhydrase CA9 Regulates Intracellular pH to Affect the Chemotherapy for Tongue Cancer

Pingyangmycin (PYM) is one of the most common chemotherapy drugs for treating tongue cancers. Carbonic anhydrase IX precursor (CA9 ) was reported to associate with PYM resistance, and related to the change of intracellular pH. We studied on whether the function of CA9 to regulate intracellular pH could affect the result of PYM chemotherapy. The BCECF AM probe was used to detect the intracellular pH. The caspase 3 activity was compared in Tca8113/ PYM cells treated with PYM or Atz, as well as Tca8113 cells with PYM. Hoechst staining revealed the karyopyknosis in all treated groups, and the vacuolization of mitochondria was observed in electron microscopy, which indicated the occurrence of apoptosis. The activation of caspase 3 was also detected. The intracellular pH was reduced as probed by BCECF-AM. We concluded that CA9 played an important role in regulating intracellular pH and Atz inhibited the CA9 activity to sensitize the cell in response to chemotherapy.