Abstract

Cancer is considered as one of the biggest threats to humans worldwide. Researchers suggest that tumour is not just a single mass, it comprises cancerous cells surrounded by noncancerous cells such as immune cells, adipocytes and cancer stem cells (CSCs) in the extracellular matrix (ECM) containing distinct components such as proteins, glycoproteins and enzymes; thus tumour microenvironment (TME) is partially complex. Multiple interactions happen in the dynamic microenvironment (ME) lead to an acidic, hypoxic and stiff ME that is considered as one of the major contributors to cancer progression and metastasis. Furthermore, TME involves in drug resistance mechanisms and affects enhanced permeability and retention (EPR) in tumours. In such a scenario, the first step to accomplish satisfying results is the identification and recognition of this ME. Then designing proper drug delivery systems can perform selectively towards cancerous cells. In this way, several targeting and stimuli/enzyme responsive drug delivery systems have been designed. More importantly, it is necessary to design a drug delivery system that can penetrate deeper into the tumours, efficiently and selectively. Various drug delivery systems such as exosomes and size-switchable nanocarriers (NCs) could decrease side effects and increase tumour treatment results by selective accumulation in tumours. In this review, TME features, current drug delivery approaches, challenges and promising strategies towards cancer treatment are discussed.

摘要

癌症被认为是全世界人类面临的最大威胁之一。研究人员认为，肿瘤不仅仅是一个单一的肿块，它包括被非癌细胞包围的癌细胞，如免疫细胞、脂肪细胞和细胞外基质 (ECM) 中的癌症干细胞 (CSC)，其中包含不同的成分，如蛋白质、糖蛋白和酶；因此，肿瘤微环境 (TME) 是部分复杂的。动态微环境 (ME) 中发生的多重相互作用导致酸性、缺氧和僵硬的 ME，被认为是癌症进展和转移的主要因素之一。此外，TME 涉及耐药机制并影响肿瘤中增强的渗透性和保留 (EPR)。在这种情况下，要取得令人满意的结果，第一步就是识别和识别这个 ME。然后设计合适的药物递送系统可以选择性地对癌细胞起作用。通过这种方式，已经设计了几种靶向和刺激/酶响应的药物递送系统。更重要的是，有必要设计一种能够高效、选择性地深入肿瘤的给药系统。各种药物递送系统，如外泌体和尺寸可切换纳米载体（NCs），可以通过在肿瘤中选择性积累来减少副作用并增加肿瘤治疗效果。在这篇综述中，讨论了 TME 的特征、当前的药物递送方法、挑战和有希望的癌症治疗策略。更重要的是，有必要设计一种能够高效、选择性地深入肿瘤的给药系统。各种药物递送系统，如外泌体和尺寸可切换纳米载体（NCs），可以通过在肿瘤中选择性积累来减少副作用并增加肿瘤治疗效果。在这篇综述中，讨论了 TME 的特征、当前的药物递送方法、挑战和有希望的癌症治疗策略。更重要的是，有必要设计一种能够高效、选择性地深入肿瘤的给药系统。各种药物递送系统，如外泌体和尺寸可切换纳米载体（NCs），可以通过在肿瘤中选择性积累来减少副作用并增加肿瘤治疗效果。在这篇综述中，讨论了 TME 的特征、当前的药物递送方法、挑战和有希望的癌症治疗策略。