Elucidate the mechanism of autophagy in supporting Lkb1-deficient lung tumorigenesis and metastasis

阐明自噬支持 Lkb1 缺陷型肺肿瘤发生和转移的机制

• 批准号: 10545748
• 负责人: Yanxiang Guo
• 金额: $ 35.28万
• 依托单位: RUTGERS BIOMEDICAL AND HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10545748
• 关键词: 5' -AMP-activated protein kinase; Ablation; Accounting; Address; Adenocarcinoma; Adenocarcinoma Cell; Alleles; Autophagocytosis; Biological Models; Bypass; Cancer Etiology; Cancer Patient; Catabolic Process; Cell Proliferation; Cell Survival; Cells; Clinical Trials; Compensation; Essential Genes; Frequencies; Genes; Genetic Predisposition to Disease; Genetically Engineered Mouse; Goals; Homeostasis; Impairment; In Vitro; K-ras mouse model; KRAS2 gene; KRASG12D; Lung Neoplasms; Malignant Neoplasms; Malignant neoplasm of lung; Mediating; Metabolic; Metabolic stress; Metabolism; Metastatic Neoplasm to the Lung; Mus; Mutate; Mutation; Mutation Detection; Neoplasm Metastasis; Non-Small-Cell Lung Carcinoma; Normal tissue morphology; Nutrient; Oncogenic; Organelles; Patients; Process; Prognosis; Property; Proteins; Resistance; Role; STK11 gene; Squamous cell carcinoma; Starvation; TP53 gene; Testing; Therapeutic; Transition Career Development Award (K22); cancer cell; cancer therapy; exome sequencing; extracellular; fatty acid metabolism; genome-wide; improved; in vivo; inducible Cre; inhibition of autophagy; insight; knock-down; lipid metabolism; loss of function; lung cancer cell; lung tumorigenesis; mortality; mouse model; mutant; neoplastic cell; novel; pre-clinical; predictive marker; response; targeted treatment; transdifferentiation; tumor; tumor growth; tumor initiation; tumor metabolism; tumorigenesis

Abstract Lung cancer is the leading cause of cancer mortality, with non-small cell lung cancer (NSCLC) accounting for more than 85% of these cases. KRAS, the most common oncogenic driver in NSCLC, confers a poor prognosis with limited treatment options. LKB1 is the third most frequently mutated gene in NSCLC. The mutations in both KRAS and LKB1 account for about 30% of NSCLC, with increased aggressiveness, a high frequency of metastases and resistance to therapeutics. Autophagy degrades proteins and organelles and recycles them to provide metabolic substrates, a function that is critical when extracellular nutrients are limited. Although the role of autophagy in cancer has been intensively studied, the precise role of autophagy in cancer, especially in vivo, remains elusive and controversial. Moreover, targeting autophagy to treat cancer generally has not contributed significantly to the advancement of clinical trials. Therefore, identifying genetic vulnerability that renders strong sensitivity to autophagy inhibition is urgently needed to improve autophagy targeted- therapies. LKB1 regulates energy homeostasis by activating AMP-activated protein kinase (AMPK), which inhibits catabolic processes and upregulates anabolic processes, in response to energy crisis. Based on earlier studies, we began to test the hypothesis that loss of LKB1 promotes cancer cell proliferation but also restricts adaptation to metabolic stress, a property that may be further compromised by loss of autophagy. Using genetically engineered mouse models (GEMMs) of NSCLC, we found that autophagy inhibition was synthetically lethal in KrasG12D/+;Lkb1-/- (KL) mediated tumorigenesis; in contrast to KL lung tumors with intact autophagy, loss of an essential autophagy gene, Atg7, dramatically impaired both tumor initiation and tumor growth. This is in sharp contrast to wild-type LKB1 (KrasG12D/+;p53-/-) tumors that are much less sensitive to essential autophagy gene ablation. Our in vitro study further revealed that autophagy modulates lipid metabolism essential for KL cancer cells to survive nutrient starvation. These observations indicate that LKB1 mutations predispose KRAS- driven NSCLC to autophagy inhibition and that LKB1 mutations could be explored as a predictive biomarker for precision lung cancer therapy. Based on our recent findings, we form our central hypothesis: autophagy compensates for LKB1 loss by maintaining the metabolism of Lkb1-deficient Kras-driven lung tumors and promoting their metastasis. We will test this with following specific aims: Aim 1. Elucidate the mechanism by which autophagy regulates lipid metabolism and KL tumorigenesis in vivo. Aim 2. Determine how autophagy promotes KL tumor metastasis. Aim 3. Identify metabolic bypasses that potentially create resistance to autophagy inhibition in KL NSCLC. Successful completion of this proposal will: (1) yield new insights into the role of autophagy in modulating cellular metabolism in support of KL lung tumorigenesis and metastasis; (2) validate the novel concept that autophagy inhibition is a selective and powerful therapeutic strategy against primary and metastatic KL NSCLC; and (3) reveal metabolic bypass as a potential mechanism of therapy resistance.

摘要肺癌是癌症死亡率的主要原因，非小细胞肺癌（NSCLC） 这些案件中有85％以上。 KRAS是NSCLC中最常见的致癌驱动力 预后不良，治疗选择有限。 LKB1是NSCLC中第三频繁突变的基因。这 KRAS和LKB1的突变占NSCLC的30％，侵略性提高，高 转移的频率和对治疗剂的抗性。自噬会降解蛋白质和细胞器，并且 回收它们以提供代谢底物，当细胞外养分受到限制时，这一功能至关重要。 尽管已经对自噬在癌症中的作用进行了深入的研究，但自噬在癌症中的确切作用，但 尤其是在体内，仍然难以捉摸且引起争议。而且，针对自噬通常治疗癌症 尚未为临床试验的发展做出重大贡献。因此，确定遗传脆弱性 迫切需要对自噬抑制的强烈敏感性，以改善自噬目标 - 疗法。 LKB1通过激活AMP激活的蛋白激酶（AMPK）来调节能量稳态，该蛋白激酶（AMPK） 抑制分解代谢过程并上调合成代谢过程，以应对能源危机。基于早期 研究，我们开始检验以下假设：LKB1的丧失会促进癌细胞的增殖，但也限制了 适应代谢应激，这种特性可能会因自噬损失而进一步损害。使用 NSCLC的基因工程小鼠模型（GEMM），我们发现自噬抑制是合成的 krasg12d/+; lkb1 - / - （kl）介导的肿瘤发生中的致命；与完整自噬的KL肺肿瘤相反，损失 ATG7必不可少的自噬基因的肿瘤启动和肿瘤生长都显着损害。这是 与野生型LKB1（KRASG12D/+; p53 - / - ）的鲜明对比，对必需自噬的敏感程度不太敏感 基因消融。我们的体外研究进一步表明，自噬调节KL必不可少的脂质代谢 癌细胞生存营养饥饿。这些观察结果表明，LKB1突变易感kras- 驱动的NSCLC对自噬抑制作用，可以将LKB1突变作为预测性生物标志物 精密肺癌治疗。根据我们最近的发现，我们形成了我们的中心假设：自噬 通过维持LKB1缺陷型KRAS驱动的肺肿瘤的代谢来弥补LKB1损失 促进他们的转移。我们将以以下特定目的进行测试：目标1。通过 自噬调节体内脂质代谢和KL肿瘤发生。目标2。确定自噬的方式 促进KL肿瘤转移。目标3。确定代谢绕过可能会产生抵抗力的代谢旁路 KL NSCLC中的自噬抑制作用。该提案的成功完成将：（1）对该角色产生新的见解 自噬调节细胞代谢，以支持KL肺肿瘤发生和转移； （2）验证 自噬抑制是针对主要和 转移KL NSCLC; （3）揭示了代谢旁路作为治疗耐药性的潜在机制。