Pemetrexed and sildenafil for lung cancer

描述（由申请人提供）：在本申请中，我们建议建立我们在培美曲塞（NCT01450384）方面的经验，并结合标准护理药物培美曲塞和批准的磷酸二酯酶-5 （PDE5）抑制剂，开发一种治疗非小细胞肺癌（NSCLC）的新药。培美曲塞与经批准的PDE5抑制剂协同作用，在体外和体内杀死NSCLC细胞。西地那非（伟哥）、伐地那非（艾力达）和他达拉非（西爱力）是PDE5抑制剂，可调节cGMP水平，诱导一氧化氮合酶（NOS）表达，增加肿瘤细胞NO和ONOO-水平。培美曲塞是作为胸苷酸合成酶抑制剂开发的，但随后被证明可以抑制AICART酶。目的1。详细确定PDE5抑制剂和培美曲塞相互作用杀死NSCLC细胞的分子机制。我们假设PDE5抑制剂和培美曲塞治疗相互作用，消除AKT、mTOR和p70 S6K活性，导致毒性自噬水平升高，c-FLIP-s、BCL-XL和MCL-1的表达降低。我们假设PDE5抑制剂和培美曲塞治疗会增加PERK/eIF2α磷酸化，从而抑制c-FLIP-s、MCL-1和BCL-XL的表达。这导致更高的游离BAX和BAK（活性）和升高的非拴系Beclin1水平，这也促进了毒性自噬的诱导。我们将确定西地那非克服NSCLC细胞培美曲塞耐药的机制。我们还假设PDE5抑制剂：(a)增加iNOS水平，使mTOR和p70 S6K失活；(b)抑制PTPase活性，促进死亡受体CD95酪氨酸磷酸化、配体非依赖性受体活化和DISC形成。目标2。通过动物模型确定PDE5抑制剂是否能增强培美曲塞对NSCLC肿瘤的治疗效果。我们将利用转基因和胸腺动物模型来研究非小细胞肺癌。Aim 2将使用人类肺癌细胞系和小鼠肺癌遗传模型的动物模型验证我们的非小细胞肺癌体外数据。我们将确定西地那非/培美曲塞治疗是否会使体内肺癌肿瘤（对顺铂）化疗增敏。

DESCRIPTION (provided by applicant): In the this application we propose to build on our experience with Pemetrexed (NCT01450384) and develop a novel drug therapy for non-small cell lung carcinoma (NSCLC) combining the standard of care drug Pemetrexed with approved phosphodiesterase-5 (PDE5) inhibitors. Pemetrexed synergizes with approved PDE5 inhibitors to kill NSCLC cells in vitro and in vivo. Sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis) are inhibitors of PDE5, which regulate cGMP levels and induce expression of nitric oxide synthase (NOS), increasing NO and ONOO- levels in tumor cells. Pemetrexed was developed as an inhibitor of thymidylate synthase but which was subsequently shown to inhibit the enzyme AICART. Aim 1. Determine in detail the molecular mechanisms by which PDE5 inhibitors and Pemetrexed interact to kill NSCLC cells. We hypothesize that PDE5 inhibitor and Pemetrexed treatment interact to abolish AKT, mTOR and p70 S6K activities leading to elevated levels of toxic autophagy and reduced expression of c-FLIP-s, BCL-XL and MCL-1. We hypothesize that PDE5 inhibitor and Pemetrexed treatment increases PERK/eIF2α phosphorylation also leading to suppression of c-FLIP-s, MCL-1 and BCL-XL expression. This results in higher free BAX and BAK (activity) and elevated levels of untethered Beclin1 which also facilitates the induction of toxic autophagy. We will determine the mechanisms by which sildenafil overcomes Pemetrexed resistance in NSCLC cells. We also hypothesize that PDE5 inhibitors: (a) increase iNOS levels which inactivates mTOR and p70 S6K and; (b) inhibit PTPase activity promoting death receptor CD95 tyrosine phosphorylation, ligand independent receptor activation and DISC formation. Aim 2. Determine using animal models whether PDE5 inhibitors enhance the therapeutic efficacy of Pemetrexed in NSCLC tumors. We will make use of transgenic and athymic animal models of NSCLC. Aim 2 will validate our in vitro data with NSCLCs using animal models with human lung cancer cell lines and mouse genetic models of lung cancer. We will determine whether sildenafil/Pemetrexed treatment chemo-sensitizes lung cancer tumors in vivo (to cisplatin).