Department of Surgery, Jefferson Pancreatic, Biliary and Related Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
Pancreas. 2010 Jul;39(5):581-94. doi: 10.1097/MPA.0b013e3181c314cd.
Pancreatic ductal adenocarcinoma (PDA) is an aggressive malignancy with an annual mortality rate close to its annual incidence. We recently demonstrated that angiotensin II (AngII) type 1 receptor (AT1R) might be involved in PDA angiogenesis. This study evaluated the antiproliferative and proapoptotic effects of an AT1R blocker, losartan, in PDA cells with different p53 mutation status.
Cell cycle was analyzed by flow cytometric analysis of DNA content; apoptosis by annexin V-fluorescein isothiocyanate (V-FITC) and terminal deoxytransferase (TdT)-mediated dUTP nick-end labeling staining; messenger RNA and protein by real-time polymerase chain reaction and Western blotting; caspase-3 activity by colorimetric assay; and promoter activity by luciferase assay.
Losartan dose-dependently decreased cell survival and increased their preG1 accumulation. It also increased p53, p21, p27, and Bax and reduced Bcl-2 and Bcl-xl expression. In wtp53 cells, losartan increased p53 transcription and activated caspase-3 in both cell lines. However, its proapoptotic effects in mtp53 cells were mainly caspase-3-dependent.
Our data describe the involvement of AT1R in PDA cell apoptotic machinery and provide the first evidences that losartan stimulates the proapoptotic signaling pathways regardless of the p53 mutation status. As loss of p53 function is frequently observed in PDA patients, our data suggest AT1R blockade as a novel therapeutic strategy to control PDA growth.
胰腺导管腺癌（PDA）是一种侵袭性恶性肿瘤，其年死亡率接近发病率。我们最近证明血管紧张素 II（AngII）1 型受体（AT1R）可能参与了 PDA 的血管生成。本研究评估了 AT1R 阻断剂氯沙坦对不同 p53 突变状态的 PDA 细胞的增殖抑制和促凋亡作用。
采用流式细胞术检测 DNA 含量分析细胞周期；用膜联蛋白 V-荧光素异硫氰酸酯（V-FITC）和末端脱氧核苷酸转移酶（TdT）介导的 dUTP 缺口末端标记染色法检测细胞凋亡；实时聚合酶链反应和 Western blot 检测信使 RNA 和蛋白质；比色法检测半胱氨酸天冬氨酸蛋白酶-3（caspase-3）活性；荧光素酶检测启动子活性。
氯沙坦呈剂量依赖性降低细胞存活率并增加其 G1 前期积累。它还增加了 p53、p21、p27 和 Bax 的表达，降低了 Bcl-2 和 Bcl-xl 的表达。在 wtp53 细胞中，氯沙坦增加了两种细胞系中 p53 的转录并激活了 caspase-3。然而，其在 mtp53 细胞中的促凋亡作用主要依赖于 caspase-3。
我们的数据描述了 AT1R 参与 PDA 细胞凋亡机制，并提供了第一个证据，即氯沙坦刺激促凋亡信号通路，而与 p53 突变状态无关。由于 PDA 患者中经常观察到 p53 功能丧失，我们的数据表明 AT1R 阻断可能是控制 PDA 生长的一种新的治疗策略。
