Phosphodiesterase-4 promotes proliferation and angiogenesis of lung cancer by crosstalk with HIF
Phosphodiesterase-4 promotes proliferation and angiogenesis of lung cancer by crosstalk with HIF
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DOI：
10.1038/onc.2012.136
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发表时间：
2013-02-28
期刊：
影响因子：
8
通讯作者：
Savai, R.
中科院分区：
文献类型：
--
作者：
Pullamsetti, S. S.;Banat, G. A.;Savai, R.
肺癌是全世界癌症死亡的主要原因。最近的数据表明，环核苷酸磷酸二酯酶 (PDE) 与各种癌症病理相关。研究了磷酸二酯酶 4 (PDE4) 的病理生理学作用及其在肺癌中可能的治疗前景。我们将 10 种不同的肺癌细胞系（腺癌、鳞状细胞癌和大细胞癌）暴露于缺氧环境，并通过实时 PCR、免疫细胞化学、蛋白质印迹和 PDE 活性测定评估了 PDE4 的表达和活性。在八个所研究的细胞系中，不同 PDE4 亚型（PDE4A 和 PDE4D）的表达和活性因缺氧而增加。此外，我们分析了 PDE4A 和 PDE4D 基因中发现的各种计算机预测缺氧反应元件 (p-HRE)。对荧光素酶报告基因构建体中的 p-HRE 进行突变分析，我们鉴定了 PDE4A 基因中的四个功能性 HRE 位点和 PDE4D 基因中的两个功能性 HRE 位点，这些位点介导报告基因的缺氧诱导。通过小干扰RNA沉默缺氧诱导因子亚基（HIF1α和HIF2α）可减少PDE4A和PDE4D的缺氧诱导。反之亦然，使用PDE4抑制剂（PDE4i）作为环磷酸腺苷（cAMP）升高剂、cAMP类似物或蛋白激酶A（PKA）调节药物以及由cAMP（EPAC）激活剂直接激活的交换蛋白，我们通过 HRE 报告基因测定、HIF 和 HIF 靶基因表达（（乳酸脱氢酶 A）、LDHA、（丙酮酸脱氢酶激酶 1）PDK1 和（血管内皮生长因子 A）VEGFA）表明，PDE4-cAMP-PKA/EPAC 轴增强了 HIF 信号传导，值得注意的是，PDE4i 抑制 PDE4 或 PDE4A 和 PDE4D 沉默可减少人肺肿瘤细胞增殖。另一方面，PDE4A 或 PDE4D 的过表达会增加人肺癌的增殖。此外，PDE4i 治疗可减少人体细胞中缺氧诱导的 VEGF 分泌，通过减弱增殖和血管生成来抑制裸鼠中的肿瘤异种移植物生长，因此，PDE4 可能是肺癌治疗的治疗靶点。 Oncogene (2013) 32, 1121-1134；doi:10.1038/onc.2012.136；2012 年 4 月 23 日在线发表
Lung cancer is the leading cause of cancer death worldwide. Recent data suggest that cyclic nucleotide phosphodiesterases (PDEs) are relevant in various cancer pathologies. Pathophysiological role of phosphodiesterase 4 (PDE4) with possible therapeutic prospects in lung cancer was investigated. We exposed 10 different lung cancer cell lines (adenocarcinoma, squamous and large cell carcinoma) to hypoxia and assessed expression and activity of PDE4 by real-time PCR, immunocytochemistry, western blotting and PDE activity assays. Expression and activity of distinct PDE4 isoforms (PDE4A and PDE4D) increased in response to hypoxia in eight of the studied cell lines. Furthermore, we analyzed various in silico predicted hypoxia-responsive elements (p-HREs) found in PDE4A and PDE4D genes. Performing mutation analysis of the p-HRE in luciferase reporter constructs, we identified four functional HRE sites in the PDE4A gene and two functional HRE sites in the PDE4D gene that mediated hypoxic induction of the reporter. Silencing of hypoxia-inducible factor subunits (HIF1 alpha and HIF2 alpha by small interfering RNA reduced hypoxic induction of PDE4A and PDE4D. Vice versa, using a PDE4 inhibitor (PDE4i) as a cyclic adenosine monophosphate (cAMP) -elevating agent, cAMP analogs or protein kinase A (PKA)-modulating drugs and an exchange protein directly activated by cAMP (EPAC) activator, we demonstrated that PDE4-cAMP-PKA/EPAC axis enhanced HIF signaling as measured by HRE reporter gene assay, HIF and HIF target genes expression ((lactate dehydrogenase A), LDHA, (pyruvate dehydrogenase kinase 1) PDK1 and (vascular endothelial growth factor A) VEGFA). Notably, inhibition of PDE4 by PDE4i or silencing of PDE4A and PDE4D reduced human lung tumor cell proliferation and colony formation. On the other hand, overexpression of PDE4A or PDE4D increased human lung cancer proliferation. Moreover, PDE4i treatment reduced hypoxia-induced VEGF secretion in human cells. In vivo, PDE4i inhibited tumor xenograft growth in nude mice by attenuating proliferation and angiogenesis. Our findings suggest that PDE4 is expressed in lung cancer, crosstalks with HIF signaling and promotes lung cancer progression. Thus, PDE4 may represent a therapeutic target for lung cancer therapy. Oncogene (2013) 32, 1121-1134; doi:10.1038/onc.2012.136; published online 23 April 2012