The Role of p53-inducible Sesn1 and Sesn2 genes in lung carcinogenesis

描述(申请人提供)：全球每年约有100万人被诊断为非小细胞肺癌(NSCLC)，其中85%将在未来5年内死亡。尽管在提高诊断和治疗效率方面做出了相当大的努力，但在过去的几十年里，死亡率的变化不到2%。由于缺乏对肺癌发生机制的了解和有效治疗的预测性策略，抗癌治疗的新的有效方法受到阻碍。在非小细胞肺癌中，P53和LKB1基因的突变是其主要特征，它们在肺癌发生中的关键作用得到了许多小鼠模型的支持。尽管参与肿瘤抑制的关键靶点尚不清楚，但P53通过对一些基因的转录调控来抑制肿瘤的发生。LKB1激酶磷酸化并激活AMPK，导致抑制mTOR激酶，这是细胞生长、增殖和代谢的关键调节因子，我在许多肺癌中激活了它。值得注意的是，与LKB1类似，P53通过激活AMPK来抑制mTOR，尽管P53和LKB1调节的信号通路之间的相互关系尚未得到很好的描述。最近，我们描述了一个新的Sestrin(SESN)基因家族的应激反应基因，在该家族中，表达是以依赖于P53的方式调节的。Sesns通过调节AMPK抑制mTOR，抑制细胞生长和增殖，激活自噬，保护细胞免受氧化损伤。Sesn1和Sesn2在大多数人肺癌中表达下调，导致肿瘤生长和血管生成的失调，因此Sesn是潜在的肿瘤抑制因子和P53的效应因子。这项拟议工作的目的是确定Sesn1和Sesn2在抑制肺癌发生和抗癌治疗结果中的重要性。为了实现这一目标，我们设立了以下具体目标：目标1：确定Sesn1和Sesn2的肿瘤抑制特性。我们将应用K-ras诱导的小鼠肺癌模型，研究Sesns的失活或过表达是否调节肺癌的发生。我们将讨论潜在的机制，其中涉及细胞增殖和细胞死亡的调节，氧化应激，自噬和新陈代谢。目的：研究AMPK-mTOR通路在Sesn1/2调控肿瘤发生中的作用。分析Sesn1/2在肺组织和肿瘤中调节AMPK-mTOR通路的作用，并研究该通路的调节是否影响Sesns的抑瘤功能。目的3：了解Sesn1/2在抗癌治疗中的作用。我们将用放射和DNA损伤药物治疗Sesn1/2缺陷和熟练的肿瘤和癌细胞，并确定Sesn1/2对肿瘤生长、细胞活力和增殖的影响。这些目标的实现使我们了解了肿瘤在肺内的抑制机制，并设计了更先进的诊断和治疗肺癌的方法，减少了巨大的死亡人数。

DESCRIPTION (provided by applicant): Around a million people are diagnosed with non-small cell lung cancer (NSCLC) worldwide each year and 85% of them will die during next 5 years. In spite of considerable efforts to improve the diagnostics and efficiency of treatment, the changes in mortality rate for the last couple decades is less than 2%. New effective approaches for anti-cancer therapy are hindered by the lack of knowledge of the mechanisms of lung carcinogenesis and a predictive strategy for efficient treatment. Among the genes dysregulated in NSCLC mutations in p53 and LKB1 are major traits, and their critical effect on lung carcinogenesis is supported by many mouse models. P53 suppresses carcinogenesis through transcriptional regulation of a number of genes, although the critical targets involved in tumor suppression are unknown. The LKB1 kinase phosphorylates and activates AMPK leading to inhibition of mTOR kinase, critical regulator of cell growth, proliferation and metabolism, which i activated in many lung cancers. Strikingly, similar to LKB1 p53 inhibits mTOR through activation of AMPK, although the inter-relation between p53- and LKB1-regulated signaling pathways is not well characterized. Recently we described a novel Sestrin (Sesn) gene family of stress-responsive genes in which expression is regulated in a p53-dependent manner. Sesns inhibit mTOR through AMPK regulation causing inhibition of cell growth and proliferation, activation of autophagy and protection against oxidative damage. Sesn1 and Sesn2 are downregulated in most human lung cancers and this leads to dysregulation of tumor growth and angiogenesis, so the Sesns are potential tumor suppressors and effectors of p53. The objective of the proposed work is to establish the importance of Sesn1 and Sesn2 in suppression of lung carcinogenesis and the outcome of anticancer treatment. To accomplish that we set up the following specific aims: Aim 1: To determine tumor suppressor properties of Sesn1 and Sesn2. We will apply of mouse model of K-ras-induced lung carcinogenesis and study whether inactivation or overexpression of Sesns modulate lung carcinogenesis. We will address the potential mechanisms, which involve regulation of cell proliferation and cell death, oxidative stress, autophagy and metabolism. Aim 2: To study the impact of the AMPK-mTOR pathway in regulation of carcinogenesis by Sesn1/2. We will analyze the role of Sesn1/2 in regulation of the AMPK-mTOR pathway in lung tissue and cancers and study whether the modulation of this pathway affects tumor-suppression function of Sesns. Aim 3: To understand the role of Sesn1/2 in anticancer treatment. We will treat Sesn1/2-deficient and proficient tumors and cancer cells with irradiation and DNA-damaging drugs and determine the impact of Sesn1/2 in tumor growth, cell viability and proliferation. The accomplishment of these goals let us to understand the mechanisms of tumor suppression in lung and design the more advanced approaches to diagnose and treat lung cancers decreasing the enormous death toll.