Improving targeted therapy in KRAS mutant lung cancers

总结/摘要 肺癌是美国死亡率的主要原因，每年影响160，000名患者， 生存率17%。大多数肺癌具有KRAS突变，其过度激活了肺癌细胞中的RAS激酶。 MAPK信号通路RAS-RAF-MEK-ERK。激酶抑制剂（KI），其靶向的关键效应子， 癌症信号通路，构成了治疗KRAS驱动的肺癌的主要策略。强效MEK 在许多肿瘤中存在抑制下游ERK信号传导的抑制剂，但这些抑制剂也抑制肿瘤中的信号传导。 正常细胞，因此它们的剂量受到毒性的限制，导致治疗指数狭窄。抗肿瘤 MEK抑制剂的作用也被代偿性或平行的FGFR 1途径的激活减弱， 导致抗药性和肿瘤复发。FGFR 1的第二种KI的共同施用 这一途径可以减轻这种耐药性，但KI的许多此类组合具有高度毒性。纳米药物 递送是克服将组合KI疗法应用于KRAS突变体的局限性的有前景的策略。 肺癌我们已经发现，带电染料之间的相互作用可以稳定不同的药物货物， 形成纳米颗粒。这些染料具有硫酸化的表面，其表现出被具有高表达的细胞类型选择性摄取。 CAV 1表达-如KRAS肺肿瘤内皮。在目标1中，我们建议调查 这种CAV 1靶向的机制，并评估其改变药物动力学和生物分布的潜力。 包装毒品与免费毒品的对比我们计划使用各种内吞途径的药理学抑制剂 以证实纳米颗粒摄取的主要机制是小窝蛋白介导的 内吞作用我们还将使用transwell试验来了解CAV 1在肺内皮细胞中的敲除方式 将改变纳米颗粒转胞质进入肿瘤环境的能力。然后我们将在体内进行 用纳米颗粒治疗的小鼠中肺肿瘤微环境的延时活体显微镜检查， 纳米颗粒如何实时靶向、相互作用和穿过肿瘤内皮。在目标2中，我们将评估 纳米颗粒递送的KI与游离KI的药效学，以及评估 纳米颗粒介导的RAS和FGFR通路抑制的治疗指数。此前，我们发现， 纳米颗粒导致肿瘤中pERK的长期抑制，并显著减弱了肿瘤中pERK的抑制。 皮肤，表明这种策略可能会抑制MEK抑制剂的主要副作用-皮肤毒性。后 完成后，该项目将产生新的发现，可能产生新的治疗KRAS的疗法 肺癌该项目将确定联合治疗可以在纳米颗粒中进行， 选择性地仅靶向肿瘤微环境。这种选择性输送将改变剂量限制。 这些药物在全身给药时观察到的毒性。从长远来看，这些结果可以用来告知 未来在犬患者中的研究、IND使能研究和临床试验。

SUMMARY/ABSTRACT Lung cancer is the leading cause of mortality in the US, affecting 160,000 patients annually with a five-year survival of 17%. The majority of lung cancers harbor KRAS mutations that overactivate the RAS kinase in the in the MAPK signaling pathway, RAS-RAF-MEK-ERK. Kinase inhibitors (KIs), which target key effectors of cancer signaling pathways, constitute a major strategy to treat KRAS-driven lung cancers. Potent MEK inhibitors exist that inhibit downstream ERK signaling in many tumors, but these also suppress signaling in normal cells so that their dosing is limited by toxicity, resulting in a narrow therapeutic index. The anti-tumor effects of MEK inhibitors are also diminished by the activation of the compensatory or parallel FGFR1 pathway, resulting in drug resistance and tumor resurgence. The co-administration of a second KI of the FGFR1 pathway can mitigate this resistance, but many such combinations of KI are highly toxic. Nanoscale drug delivery is a promising strategy to overcome the limitations of applying combination KI therapy to KRAS mutant lung cancer. We have discovered that interactions between charged dyes can stabilize diverse drug cargoes to form nanoparticles. These dyes have a sulfated surface that exhibits selective uptake by cell types with high CAV1 expression – such as KRAS lung tumor endothelium. In Aim 1, we propose to investigate the mechanism of this CAV1 targeting and assess its potential to alter the pharmacokinetic and biodistribution of packaged drugs versus free drugs. We plan to use pharmacological inhibitors of various endocytosis pathways in endothelial cells in vitro to confirm that the primary mechanism of nanoparticle uptake is caveolin-mediated endocytosis. We will also use transwell assays to understand how CAV1 knock out in lung endothelial cells would alter the ability of nanoparticles to transcytose into the tumor environment. We will then conduct in vivo time lapse intravital microscopy of the lung tumor microenvironment in mice treated with nanoparticles to see in real-time how the nanoparticles target, interact, and cross the tumor endothelium. In Aim 2, we will assess the pharmacodynamics of nanoparticle delivered KIs versus free KIs as well as assess improvements to therapeutic index of nanoparticle-mediated RAS and FGFR pathway inhibition. Previously, we have found that nanoparticles resulted in long-term inhibition of pERK in tumors and significantly attenuated inhibition in the skin, demonstrating that this strategy may obviate a major side-effect of MEK inhibitors – skin toxicities. Upon completion, this project will result in new findings that may produce novel therapies for the treatment of KRAS lung cancers. This project would establish that combination therapies could be delivered in nanoparticles that selectively target only the tumor microenvironment. This selective delivery would alter the dose limiting toxicities seen by these drugs upon systemic administration. Long term, these results can be used to inform future investigations in canine patients, IND-enabling studies, and clinical trials.