Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul 110-744, Korea.
Acta Pharmacol Sin. 2011 Jul;32(7):912-20. doi: 10.1038/aps.2011.24. Epub 2011 Jun 13.
The hypoxic condition within large or infiltrative hypovascular tumors produces intracellular acidification, which could activate many signaling pathways and augment cancer cell growth and invasion. Carbonic anhydrase-IX (CA-IX) is an enzyme lowering pH. This study is to examine whether hypoxia induces CA-IX in hepatocellular carcinoma (HCC) cells, and to evaluate its clinical implication in HCC patients.
Human HCC cell lines (Huh-7 and HepG2 cells) were used, and cell growth was assessed using MTS assay. CA-IX expression and apoptotic/kinase signaling were evaluated using immunoblotting. The cells were transfected with CA-IX-specific siRNA, or treated with its inhibitor 4-(2-aminoethyl) benzenesulfonamide (CAI#1), and/or the hexokinase II inhibitor, 3-bromopyruvate (3-BP). A clinic pathological analysis of 69 patients who underwent an HCC resection was performed using a tissue array.
Incubation of HCC cells under hypoxia (1% O₂, 5% CO₂, 94% N₂) for 36 h significantly increased CA-IX expression level. CAI#1 (400 μmol/L) or CA-IX siRNA (100 μmol/L) did not influence HCC cell growth and induce apoptosis. However, CAI#1 or CA-IX siRNA at these concentrations enhanced the apoptosis induced by 3-BP (100 μmol/L). This enhancement was attributed to increased ER stress and JNK activation, as compared with 3-BP alone. Furthermore, a clinic pathological analysis of 69 HCC patients revealed that tumor CA-IX intensity was inversely related to E-cadherin intensity.
Inhibition of hypoxia-induced CA-IX enhances hexokinase II inhibitor-induced HCC apoptosis. Furthermore, CA-IX expression profiles may have prognostic implications in HCC patients. Thus, the inhibition of CA-IX, in combination with a hexokinase II inhibitor, may be therapeutically useful in patients with HCCs that are aggressively growing in a hypoxic environment.
大或浸润性低血管肿瘤内的缺氧条件会导致细胞内酸化，从而激活许多信号通路并促进癌细胞生长和侵袭。碳酸酐酶-IX（CA-IX）是一种降低 pH 值的酶。本研究旨在探讨缺氧是否会诱导肝癌（HCC）细胞中的 CA-IX，并评估其在 HCC 患者中的临床意义。
使用人肝癌细胞系（Huh-7 和 HepG2 细胞），并通过 MTS 分析评估细胞生长。使用免疫印迹评估 CA-IX 表达和凋亡/激酶信号。用 CA-IX 特异性 siRNA 转染细胞，或用其抑制剂 4-(2-氨基乙基)苯磺酰胺（CAI#1）和/或己糖激酶 II 抑制剂 3-溴丙酮酸（3-BP）处理细胞。对 69 例接受 HCC 切除术的患者进行了组织阵列的临床病理分析。
将 HCC 细胞在缺氧（1% O₂，5% CO₂，94% N₂）中孵育 36 小时显著增加 CA-IX 表达水平。CAI#1（400 μmol/L）或 CA-IX siRNA（100 μmol/L）不影响 HCC 细胞生长并诱导细胞凋亡。然而，这些浓度的 CAI#1 或 CA-IX siRNA 增强了 3-BP（100 μmol/L）诱导的凋亡。与单独使用 3-BP 相比，这种增强归因于内质网应激和 JNK 激活的增加。此外，对 69 例 HCC 患者的临床病理分析表明，肿瘤 CA-IX 强度与 E-钙黏蛋白强度呈负相关。
抑制缺氧诱导的 CA-IX 增强了己糖激酶 II 抑制剂诱导的 HCC 细胞凋亡。此外，CA-IX 表达谱可能对 HCC 患者具有预后意义。因此，抑制 CA-IX 与己糖激酶 II 抑制剂联合使用可能对在缺氧环境中生长迅速的 HCC 患者具有治疗意义。
