纳米载药系统靶向肿瘤微环境治疗策略

肿瘤的发生通常被认为是内在遗传物质与机体的内外环境相互作用的结果，在肿瘤的发生、生长、侵袭和转移的过程中，肿瘤微环境有着极大的促进作用，其不仅提供了一个肿瘤细胞浸润的场所，还促进肿瘤与其进行酶和细胞因子等物质的交换，帮助肿瘤细胞增殖、分化、自我更新，同时改变宿主的微环境，因此靶向肿瘤微环境的治疗是一种重要手段。随着近年来纳米给药技术发展迅速，给肿瘤的诊断治疗带来新的途径，但肿瘤血管异常、间质压力高等微环境因素限制了纳米给药系统的传递效果，纳米粒表面化学也正从传统的合成聚合物发展到更多的生物激发策略。本文主要从肿瘤微环境的相关靶点及不同类型纳米载药系统靶向策略进行详细综述，并提出了改善纳米药物传递系统的方法与思考。

Nano drug delivery system based strategies to target tumor microenvironment

Tumor occurrence is usually recognized as the interplay between genetic variations within the tumor and the environment. During a long time, great effort has been made in killing cancer cells. However, the role of tumor microenvironment has been largely ignored, which plays an important role in tumor generation, growth, invasion and metastasis. Meanwhile, tumor microenvironment not only facilitates the tumor infiltration, but also promotes the exchange of enzymes and cytokines to aid tumor proliferation, differentiation and self-renewal. Thus, better understanding of tumor microenvironment shows great importance. Recent developments in nanotechnology have brought new approaches to cancer diagnosis and therapy. Nanoparticles were suggested to show enhanced efficacy, while simultaneously reducing side effects and promoting bioavailability, owing to properties such as tumor localization and active cellular uptake. Additionally, nanoparticle surface chemistry has evolved from conventional synthetic polymers to more biologically inspired strategies, including cell membrane and self-recognition peptides, to minimize nonspecific uptake of nanoparticles. In the current review, we highlight the targets in tumor microenvironment and the strategies of nano drug delivery system to target tumor microenvironment for the treatment of cancer. We also highlight design considerations to improve nano drug delivery.