Targeting autophagy to increase the sensitivity of LKB1-deficient lung tumors to angiogenesis inhibitor

摘要 肺癌是世界范围内的主要癌症杀手，其中非小细胞肺癌（NSCLC）占 超过85%的病例。KRAS和LKB 1是肺癌患者中最常见的两种突变。 携带KRAS和LKB 1共突变的肺癌患者显示出增加的侵袭性， 转移的频率和对所有标准疗法的抗性。癌细胞从血液循环中获取营养 血血管生成抑制剂，阻止血管的生长，已被用于肺癌 治疗然而，多项临床前和临床研究已经报道，LKB 1缺失导致 对血管生成抑制剂耐药，无论是否接受化疗。一个获得 对抗血管生成药物的抗性源于通过诱导代谢共生的肿瘤适应。自噬是 一个细胞吞噬自身以产生积木、能量和氧化还原稳态，并消除 废物的代谢压力，如营养消耗。包括我们小组在内的许多研究都证明 在细胞外营养缺乏的反应中，癌细胞可以通过自噬来吸收营养， 介导的细胞内再循环用于肿瘤生长、增殖、存活和恶性。因此，我们认为， 同时从细胞内和细胞外来源消除营养物质的可用性可能是 成功治疗癌症的创新策略。特别是，我们最近证明了自噬是 在Kras突变型Lkb 1缺陷（KL）肺肿瘤中上调，自噬抑制在KL-1中是合成致死的。 介导的肿瘤发生。此外，自噬消融的抗肿瘤作用在Lkb 1中更为深刻。 与Lkb 1野生型（WT）KP（Kras突变型p53缺陷型）肺肿瘤相比，基于上述 理论基础和初步研究，我们形成了中心假说：自噬介导的细胞内循环 补偿血管生成抑制剂引起的营养缺乏，以支持KL的存活和生长 肺部肿瘤我们将：1）确定细胞自主性自噬在赋予抗性中的作用和机制 KL肺肿瘤对血管生成抑制剂的敏感性;以及2）确定靶向自噬是否可以使Lkb 1缺陷型 KL肺肿瘤，而不是Lkb 1-WT KP肺肿瘤，对血管生成抑制剂。我们的研究将确定LKB 1是否 突变可以作为一种预测性生物标志物进行探索， 自噬抑制剂和血管生成抑制剂。一旦我们的假设在临床前小鼠模型中得到证实， 自噬抑制剂羟氯喹联合血管生成抑制剂贝伐单抗新疗法 可以自然地立即转化为临床试验，用于治疗携带共- KRAS和LKB 1突变。

ABSTRACT Lung cancer is the leading cancer killer worldwide, with non-small cell lung cancer (NSCLC) accounting for more than 85% of these cases. KRAS and LKB1 are the two most frequent mutations detected in lung cancer patients. Lung cancer patients bearing co-mutations of KRAS and LKB1 show increased aggressiveness, a high frequency of metastases, and resistance to all standard therapies. Cancer cells acquire nutrients from circulating blood. Angiogenesis inhibitors, which block the growth of blood vessels, have been used for lung cancer treatment. However, multiple preclinical as well as clinical studies have reported that LKB1 depletion confers resistance to angiogenesis inhibitors, regardless of whether or not receiving chemotherapy. One of acquired resistance to antiangiogenics stems from tumor adaptations by induction of metabolic symbiosis. Autophagy is a process that cell eats itself to generate building blocks, energy, and redox homeostasis, and for elimination of waste in response to metabolic stress, such as nutrient depletion. Many studies including our group have proved that in response to extracellular nutrient deprivation, cancer cells can scavenge nutrients through autophagy- mediated intracellular recycling for tumor growth, proliferation, survival, and malignancy. Therefore, simultaneously eliminating nutrient availability from both intracellular and extracellular sources could be an innovative strategy for a successful cancer treatment. In particular, we recently demonstrated that autophagy is upregulated in Kras-mutant Lkb1-deficient (KL) lung tumor and autophagy inhibition is synthetically lethal in KL- mediated tumorigenesis. Moreover, anti-tumor effect by autophagy ablation is much more profound in Lkb1- deficient KL lung tumor than Lkb1 wild type (WT) KP (Kras-mutant p53-deficient) lung tumor. Based on above rationale and preliminary studies, we formed central hypothesis: autophagy-mediated intracellular recycling compensates for nutrient deprivation caused by angiogenesis inhibitor to support the survival and growth of KL lung tumor. We will: 1) determine the role and mechanism of cell-autonomous autophagy in conferring resistance of KL lung tumor to angiogenesis inhibitor; and 2) Determine if targeting autophagy can sensitize Lkb1-deficient KL lung tumor, but not Lkb1-WT KP lung tumor, to angiogenesis inhibitor. Our study will determine if LKB1 mutations could be explored as a predictive biomarker for precision lung cancer therapy using the combination of autophagy inhibitor and angiogenesis inhibitor. Once our hypothesis is confirmed in preclinical mouse models, the novel therapy of autophagy inhibitor hydroxychloroquine combined with angiogenesis inhibitor Bevacizumab can be naturally and immediately translated into clinical trials for treating lung cancer patients harboring co- mutations of KRAS and LKB1.