The P450 Epoxygenases as Pro-Oncogenic Enzymes

描述（由申请人提供）：我们的总体目标是确定新的、更安全的、耐受性更好的肺癌抗血管生成疗法。虽然靶向肿瘤细胞或肿瘤相关脉管系统的疗法目前用于治疗肺癌，但它们具有主要局限性，包括：1）耐药性的发展; 2）抗血管生成疗法后高血压、蛋白尿和肠穿孔的发展;和3）大多数患者仍然死于原发性或转移性疾病。这些局限性强调了迫切需要新的，更安全的，更好的耐受性的治疗方法来治疗这种毁灭性的疾病。该提案侧重于两种不同但相关的分子类别的贡献，这些分子可影响肺癌进展，即细胞色素P450花生四烯酸CYP 2C环氧合酶和核过氧化物酶体增殖物激活受体α（PPARa）。我们的目标是：a）提供证据，而CYP 2C是促肿瘤发生酶，过氧化物酶激活受体？作为一种新的抗肿瘤基因发挥作用，和B）测试新的假设，即PPAR的抗肿瘤活性？配体存在于它们下调CYP 2C在PPAR？依赖的方式。为此，我们提供的证据表明：1）内皮细胞CYP 2C表氧化酶代谢产物（EET）是促血管生成的体外和体内; 2）EET水平的降低抑制肿瘤生长和血管生成; 3）破坏小鼠Cyp 2c 44基因，或其下调通过过氧化物酶体增殖物激活受体？活化，降低体外内皮细胞功能和体内肿瘤生长和血管形成; 4）Cyp 2c 44的代谢同系物人CYP 2C 9在人NSCLC的血管系统中上调;和5）两种CYP 2C 9变体，即CYP 2C 9 *2和CYP 2C 9 *3，显示出显著降低的促血管生成EET生物合成活性。在本提案中，我们将确定：a）如果PPAR？配体可以被视为一类新的更安全和更好的耐受性抗血管生成和/或抗肿瘤药物; B）Cyp 2c 44和PPAR？通过利用非小细胞肺癌（NSCLC）的自发性和人原位模型，确定CYP 2C 9 *2和CYP 2C 9 *3变体与肺癌的发生、生长和进展的关系;以及c）来自NSCLC患者队列的DNA中CYP 2C 9 *2和CYP 2C 9 *3变体的频率的变化是否与由于其降低的EET合酶活性而导致的NSCLC的发病率降低和/或进展相关。具体来说，我们将研究在目标1的Cyp 2c 44在原发性非小细胞肺癌的发展中的作用，在目标2的贡献，人的过氧化物酶体增殖物激活受体？及其配体活化对NSCLC进展的影响;目的3 NSCLC与人CYP 2C 9和PPAR？基因.这些研究可能作为前奏，未来的临床研究，以验证的有用性？配体作为新的、有效的和更安全的抗血管生成剂用于癌症治疗。此外，它们可能导致关于P450在癌症中的作用的范式转变：从其在抗癌药物代谢中的已知作用转变为肿瘤生长/血管生成生物学中的关键参与者，从而成为抗癌药物开发的潜在有价值的靶标。

DESCRIPTION (provided by applicant): Our overall goal is to identify new, safer, and better-tolerated anti-angiogenic therapies for lung cancer treatment. While therapies targeting tumor cells or tumor-associated vasculature are currently in place for the treatment of lung cancer, they have major limitations, including: 1) the development of resistance; 2) the development of hypertension, proteinuria, and bowel perforation following anti-angiogenic therapy; and 3) most patients still die from primary or metastatic disease. These limitations underscore an urgent need for new, safer, and better-tolerated therapies for the treatment of this devastating disease. This proposal focuses on the contribution of two different, but linked, classes of molecules that can affect lung cancer progression, namely the cytochrome P450 arachidonic acid CYP2C epoxygenases and the nuclear peroxisomal proliferator activated receptor alpha (PPARa). We aim to: a) provide evidence that whereas the CYP2C are pro-tumorigenic enzymes, PPAR? functions as a new anti-tumorigenic gene, and b) test the novel hypothesis that the anti-tumorigenic activity of PPAR? ligands resides in their ability to downregulate CYP2C expression in a PPAR?-dependent fashion. To this end, we provide evidence that: 1) the endothelial CYP2C epoxygenase metabolites (EETs) are pro-angiogenic in vitro and in vivo; 2) reduction in EET levels inhibits tumor growth and angiogenesis; 3) disruption of the murine Cyp2c44 gene, or its downregulation via PPAR? activation, reduces endothelial cell function in vitro and tumor growth and vascularization in vivo; 4) the human CYP2C9, the metabolic homologue of Cyp2c44, is upregulated in the vasculature of human NSCLC; and 5) two CYP2C9 variants, namely CYP2C9*2 and CYP2C9*3, show markedly reduced pro-angiogenic EET biosynthetic activity. In this proposal we will determine: a) if PPAR? ligands can be viewed as a new class of safer and better-tolerated anti-angiogenic and/or anti-tumorigenic drugs; b) the contribution of Cyp2c44 and PPAR? to the initiation, growth, and progression of lung cancer by utilizing a spontaneous and a human orthotopic model of non small cell lung cancer (NSCLC); and c) if changes in the frequency of the CYP2C9*2 and CYP2C9*3 variants in DNAs from a cohort of NSCLC patients are associated with decreased incidence and/or progression of NSCLC due to their reduced EET synthase activity. Specifically, we will study in Aim 1 the role of Cyp2c44 in the development of primary NSCLC; in Aim 2 the contribution of human PPAR? and its ligand activation to the progression of NSCLC; and in Aim 3 associations between NSCLC and variants in human CYP2C9 and PPAR? genes. These studies may serve as prelude to future clinical studies to validate the usefulness of PPAR? ligands as new, effective, and safer anti-angiogenic agents for cancer treatment. In addition, they might lead to a paradigm shift regarding the role of P450 in cancer: from its known role in anti-cancer drug metabolism to that of a key participant in the biology of tumor growth/angiogenesis and thus a potentially valuable target for anti-cancer drug development.