诊断兼治疗的多功能肿瘤靶向纳米递释系统

肿瘤靶向纳米递释系统可特异性转运抗肿瘤药物至肿瘤部位发挥疗效,已成为国内外研究热点。兼具诊断与治疗的多功能肿瘤靶向纳米递释系统是近年来出现的一类新型纳米递释系统,可同时实现分子诊断试剂、抗肿瘤药物的肿瘤靶向递释,同步进行对肿瘤的诊断与治疗。本文综述了纳米递释系统的肿瘤靶向机制,以及诊断与治疗双功能系统的构建。     

pH敏感型纳米递药系统在肿瘤靶向治疗中的作用

目的 综述目前pH敏感纳米递药系统用于肿瘤靶向治疗中的国内外研究进展。方法 在Pubmed和Google上检索近年国内外资料,阐明pH敏感纳米递药系统靶向肿瘤治疗的作用机制,对超顺磁性纳米粒、胶束、树状大分子等相关研究成果进行总结和评价。结果 传统肿瘤化疗药物普遍存在疗效低、副作用大等问题,而近年来研发的pH响应的纳米载体可通过EPR效应积聚于肿瘤组织,并在弱酸性的肿瘤细胞外液或经内吞作用后在细胞质或溶酶体中释放药物。该pH敏感型载体能促进药物的靶向递送,在减少系统性副作用的同时提高肿瘤化疗疗效。结论 pH敏感纳米递药系统在肿瘤靶向治疗中具有广阔的应用前景,开发具有靶向性、高效性、安全性的递药系统是目前该领域研究主要方向之一。     

肿瘤靶向纳米载药系统的设计与构建

近年来将纳米载药系统应用于肿瘤靶向递药的研究层出不穷。与正常组织相比,肿瘤组织具有较低的p H环境、大量新生血管生成、不规则的血流灌注、局部缺氧等特异性的微环境,利用这些特点进行合理的纳米载药系统设计能够实现肿瘤部位的高效递药及深层穿透,显著提高肿瘤治疗效果。针对现有的肿瘤靶向纳米载药系统的构建与设计方法进行综述,以阐述纳米载药系统在肿瘤靶向传递中的研究进展。     

叶酸受体介导的肿瘤靶向纳米递药系统

叶酸受体在上皮源性的恶性肿瘤细胞膜表面高度表达。叶酸靶向纳米递药系统具有叶酸-叶酸受体主动靶向和纳米递药系统被动靶向的双重优势,可实现化疗药物对肿瘤组织的靶向递送,有效提高药物疗效,减少毒副作用。本文就近年来研究较多的叶酸-脂质体、叶酸-树枝状聚合物、叶酸-聚合物胶束、叶酸-纳米球等叶酸受体介导的肿瘤靶向递药系统进行综述。     

基于癌相关成纤维细胞的药物递释系统的研究进展

癌相关成纤维细胞(CAFs)是原发性肿瘤基质中最突出的细胞类型,是肿瘤微环境中的主要组成部分,对肿瘤的发生、发展及转移产生重要影响,具有促进肿瘤生长、侵袭和免疫抑制作用。通过抑制CAFs能够起到抗肿瘤的作用,构建基于靶向CAFs的药物递释系统已成为当今肿瘤治疗的重要策略。目前针对CAFs的治疗靶点主要有成纤维细胞生长因子受体、成纤维细胞活化蛋白和肌腱蛋白C等,药物递释系统主要包括以胶束、脂质体、纳米复合物以及无机纳米粒为载体的药物递释系统等。     

基于纳米递药系统的创新药物制剂研究

纳米技术是21世纪世界各国经济发展的驱动力之一。纳米技术在医药领域的应用极为广泛,其中最引人注目的是纳米递药系统。本期"靶向纳米递药系统的创新药物制剂设计"专题,邀请国内几位知名药剂学专家综述了靶向纳米递药系统多个研究方向的新进展。主要包括:阳离子纳米材料及其纳米递药系统的毒性;靶向纳米递药系统载体材料的设计、制备和表征;肿瘤靶向、脑部肿瘤靶向、基因靶向纳米递药系统的设计原理、构建方法和体内外效果。这些综述,较全面地反映了纳米递药系统的设计、构建、表征、实效、     

基于靶向纳米递药系统用于胰腺癌化疗中的研究现状

胰腺癌是一种恶性程度较高、诊断和治疗均较困难的消化道系统肿瘤。胰腺癌的传统化疗方案靶向性不高,治疗效率低,存在一系列的药物不良反应。近年来纳米靶向递药系统迅猛发展,为胰腺癌的治疗提供了许多的新思路。本文综述了近年来基于靶向纳米递药系统用于胰腺癌化疗的研究进展,从被动靶向、物理化学靶向、主动靶向和化疗药物的联合运载四个方面中的应用进行介绍,以期为胰腺癌的临床治疗提供新的思路和方法。     

细胞膜仿生纳米技术在肿瘤靶向递药系统中的研究进展

纳米技术的发展为构建安全高效、精准可控的药物递送系统(drug delivery system, DDS)提供了可能。其中,有机或无机合成纳米载体已被广泛报道并用于肿瘤治疗药物的递送,但部分载体存在易被机体内免疫系统清除、制备过程繁琐和体内安全性较差等问题。近年来,随着生物医学的发展,基于仿生技术的生物膜介导的纳米药物递送系统,因其有机整合了天然生物膜的低免疫原性、肿瘤靶向性和智能纳米载体设计的可调控性、多功能性,有望实现纳米技术在肿瘤靶向治疗上的新突破。本文基于细胞膜仿生技术和纳米医学在肿瘤治疗领域的最新进展,从细胞膜仿生纳米技术的实验基础、膜仿生纳米递药平台的分类和在肿瘤靶向治疗上的应用三方面进行阐述,旨在为仿生智能DDS的设计及其在肿瘤靶向治疗中的发展提供参考。     

生物素在肿瘤靶向递药中的研究进展

运用靶向递药系统给药是目前治疗癌症的有效方法,靶向配体的选择是靶向递药的关键。生物素受体在多数肿瘤细胞表面过表达,但在正常细胞中低表达或不表达,因此,生物素可作为配体与药物载体相连,用于肿瘤靶向递药。简述生物素及生物素受体,综述生物素修饰的脂质体、胶束、纳米粒等载药系统在肿瘤靶向诊断和治疗中的研究进展,以期为相关研究开发与临床应用提供参考。     

纳米仿生型肿瘤疫苗的研究进展

肿瘤疫苗作为肿瘤免疫疗法的一种,为癌症治疗提供了新策略。利用纳米仿生材料包被肿瘤抗原,构建纳米仿生型肿瘤疫苗,可实现抗原的靶向递释,具有高效性和安全性等优点。因此,纳米仿生型疫苗成为当今的研究热点。据此,本文综述了新型纳米仿生肿瘤疫苗的研究进展,并介绍了其临床应用及同其他疗法的联合应用情况。     

Biodegradable polymers for targeted delivery of anti-cancer drugs

ABSTRACT

Introduction: Biodegradable polymers have been used for more than three decades in cancer treatment and have received increased interest in recent years. A range of biodegradable polymeric drug delivery systems designed for localized and systemic administration of therapeutic agents as well as tumor-targeting macromolecules has entered into the clinical phase of development, indicating the significance of biodegradable polymers in cancer therapy.

Areas covered: This review elaborates upon applications of biodegradable polymers in the delivery and targeting of anti-cancer agents. Design of various drug delivery systems based on biodegradable polymers has been described. Moreover, the indication of polymers in the targeted delivery of chemotherapeutic drugs via passive, active targeting, and localized drug delivery are also covered.

Expert opinion: Biodegradable polymer-based drug delivery systems have the potential to deliver the payload to the target and can enhance drug availability at desired sites. Systemic toxicity and serious side effects observed with conventional cancer therapeutics can be significantly reduced with targeted polymeric systems. Still, there are many challenges that need to be met with respect to the degradation kinetics of the system, diffusion of drug payload within solid tumors, targeting tumoral tissue and tumor heterogeneity.     

The importance of nanoparticle shape in cancer drug delivery

Introduction: Nanoparticles have been successfully used for cancer drug delivery since 1995. In the design of commercial nanoparticles, size and surface characteristics have been exploited to achieve efficacious delivery. However, the design of optimized drug delivery platforms for efficient delivery to disease sites with minimal off-target effects remains a major research goal. One crucial element of nanoparticle design influencing both pharmacokinetics and cell uptake is nanoparticle morphology (both size and shape). In this succinct review, the authors collate the recent literature to assess the current state of understanding of the influence of nanoparticle shape on the effectiveness of drug delivery with a special emphasis on cancer therapy.

Areas covered: This review draws on studies that have focused on the role of nonspherical nanoparticles used for cancer drug delivery. In particular, the authors summarize the influence of nanoparticle shape on biocirculation, biodistribution, cellular uptake and overall drug efficacy. By comparing spherical and nonspherical nanoparticles, they establish some general design principles to serve as guidelines for developing the next generation of nanocarriers for drug delivery.

Expert opinion: Pioneering studies on nanoparticles show that nonspherical shapes show great promise as cancer drug delivery vectors. Filamentous or worm-like micelles together with other rare morphologies such as needles or disks may become the norm for next-generation drug carriers, though at present, traditional spherical micelles remain the dominant shape of nanocarriers described in the literature due to synthesis and testing difficulties. The few reports that do exist describing nonspherical nanoparticles show a number of favorable properties that should encourage more efforts to develop facile and versatile nanoparticle synthesis methodologies with the flexibility to create different shapes, tunable sizes and adaptable surface chemistries. In addition, the authors note that there is a current lack of understanding into the factors governing (and optimizing) the inter-relationships of size, surface characteristics and shapes of many nanoparticles proposed for use in cancer therapy.     

Pharmacogenomics-based RNA interference nanodelivery: focus on solid malignant tumors

Introduction: RNA interference represents one of the most promising strategies in fighting disease. However, small RNA interference faces substantial challenges for in vivo application due to the inherent instability of the RNA interference molecule. Among the nonviral gene delivery carriers, nanoparticles have attracted interest due to their success in various model systems. Nanomaterials have unique properties compared to conventional bulk materials that may be applicable in this setting. The nanoparticle complex carrying small interference RNA can undergo surface modification to achieve targeted modification for tissue-specific delivery. However, toxicity issues of the delivery systems need to be addressed and they require a pharmacogenomic profile of their own.

Areas covered: The authors review pharmacogenomics, toxicogenomics, nanoparticle-based drug delivery, and small interference RNA, with a focus on how logically engineered nanoparticle delivery systems can be used for personalized medicine in malignant tumors.

Expert opinion: Pharmacogenomics may be helpful in addressing possible individualized drug response for both the gene silencing capability of the delivered siRNA and the nanoparticle drug delivery system as both complete and distinct units. This may be done by assessing variations in gene expressions and single nucleotide polymorphisms. Patient profiling may be key as patient noncompliance due to toxicity plays a major role in treatment failure.     

Challenges in SN38 drug delivery: current success and future directions

Introduction: Clinical use of SN38 is limited by its poor aqueous solubility and hydrolysis of the lactone ring at pH > 6 to inactive carboxylate form. A variety of drug delivery systems have been developed to improve the solubility and stability of SN38, and reduce its toxicity. A few noteworthy formulations with some success in initial phases of clinical trials are reported.

Areas covered: This work aims to provide a comprehensive review on the various techniques and strategies employed (physical, chemical and biological methods) to improve physicochemical properties and to deliver the drug efficiently to the cancer cells. Physical methods such as nanoparticle encapsulation, cyclodextrin complexation; chemical methods such as prodrugs, polymer-, albumin- and immunoconjugates; and enzyme activated prodrug therapy are discussed.

Expert opinion: The challenges in SN38 drug delivery may be overcome by two ways: ensuring multiple layers of protection against degradation and slow but sustained release of therapeutically effective drug concentrations. It may also be achieved by preparing a polymer–drug conjugate and further encapsulating the conjugate in suitable carrier system; tumor-targeted SN38 delivery by using immunoconjugates, enzyme-activated prodrug therapy and antibody-directed nanoparticle delivery. However, selection of a suitable ligand for tumor targeting and use of safe and biocompatible nanoparticle systems play an important role in realizing this goal.     

The role of cell cycle in the efficiency and activity of cancer nanomedicines

Introduction: With a wealth of knowledge on the effect of nanoparticle properties, including size, shape, charge and composition, on intracellular delivery, little has been reported on the effect of the cell cycle on the intracellular delivery and activity of nanomedicines including non-viral gene delivery systems. The aim of this review is to shed a light on this topic.

Areas covered: It is now evident that nanoparticle cell uptake varies with the cell cycle phase. This review addresses this variation by dissecting the effect of cell population heterogeneity on the intracellular delivery and activity of nanomedicines with a special focus on non-viral gene delivery and combination therapy modalities that utilize cell cycle inhibitors as co-targets for therapy. In addition, the importance of three-dimensional (3D) culture systems in the drug delivery field within the context of the cell cycle will be addressed.

Expert opinion: The understanding of the cell cycle machinery has improved dramatically over the last few decades. Developing combination therapy modalities that target the cell cycle to achieve better cancer patient outcome should now be the focus. Furthermore, more effort should be placed on developing a reliable, consistent, high throughput 3D cell culture system since these systems more closely resemble the cell cycle status of in vivo tumors. A switch from 2D to 3D culture systems, to more accurately predict the in vivo efficacy of nanoparticle drug delivery systems, is desirable.     

Differences in physicochemical properties to consider in the design,evaluation and choice between microparticles and nanoparticles for drug delivery

Introduction: The increase in the development of novel nanoparticle drug delivery systems makes the choice between micro- and nanoscale drug delivery systems ubiquitous. Changes in physical and chemical properties between micro- to nanosized particles give them different properties that influence their physiological, anatomical and clinical behavior and therefore potential application.

Areas covered: This review focuses on the effect changes in the surface-to-volume ratio have on the thermal properties, solubility, dissolution and crystallization of micro- versus nanosized drug delivery systems. With these changes in the physicochemical properties in mind, the review covers computational and biophysical approaches to the design and evaluation of micro- and nanodelivery systems. The emphasis of the review is on the effect these properties have on clinical performance in terms of drug release, tissue retention, biodistribution, efficacy, toxicity and therefore choice of delivery system.

Expert opinion: Ultimately, the choice between micro- and nanometer-sized delivery systems is not straightforward. However, if the fundamental differences in physical and chemical properties are considered, it can be much easier to make a rational choice of the appropriate drug delivery system size.     

Galactosylated bovine serum albumin nanoparticles for parenteral delivery of oridonin: tissue distribution and pharmacokinetic studies

Abstract

Bovine serum albumin (BSA) nanoparticle is a promising drug carrier system. Oridonin (ORI)-loaded galactosylated BSA nanoparticle (ORI-GB-NP) was prepared for liver targeting delivery of ORI. This work was designed to investigate the in vitro release, in vivo pharmacokinetics and tissue distribution of ORI-GB-NP. ORI-GB-NP was prepared by the desolvation method. The particle size of ORI-GB-NP was 172.0?±?8.3?nm with narrow size distribution. The in vitro release of ORI-GB-NP exhibited biphasic drug release pattern with an initial burst release and consequently sustained release. Pharmacokinetic analysis displayed that ORI-GB-NP and ORI-loaded BSA nanoparticle (ORI-BSA-NP) could enhance the drug plasma level and prolong the circulation time in contrast with ORI solution. Meanwhile, compared with ORI-BSA-NP, ORI-GB-NP could deliver more ORI to liver and simultaneously reduce the toxicity of ORI to heart, lung and kidney. In conclusion, ORI-GB-NP could be a promising drug delivery system for liver cancer therapy.     

Recent advancements in nanoparticle based drug delivery for gastrointestinal disorders

Introduction: The emergent field of nanoparticles has presented a wealth of opportunities for improving the treatment of human diseases. Recent advances have allowed for promising developments in drug delivery, diagnostics, and therapeutics. Modified delivery systems allow improved drug delivery over traditional pH, microbe, or receptor dependent models, while antibody association allows for more advanced imaging modalities. Nanoparticles have potential clinical application in the field of gastroenterology as they offer several advantages compared to the conventional treatment systems including target drug delivery, enhanced treatment efficacy, and reduced side effects.

Areas covered: The aim of this review article is to summarize the recent advancements in developing nanoparticle technologies to treat gastrointestinal diseases. We have covered the application of nanoparticles in various gastrointestinal disorders including inflammatory bowel disease and colorectal cancer. We also have discussed how the gut microbiota affects the nanoparticle based drug delivery in the gastrointestinal tract.

Expert opinion: Nanoparticles based drug delivery offers a great platform for targeted drug delivery for gastrointestinal disorders. However, it is influenced by the presence of microbiota, drug interaction with nanoparticles, and cytotoxicity of nanoparticles. With the advancements in nanoparticle technology, it may be possible to overcome these barriers leading to efficient drug delivery for gastrointestinal disorders based on nanoparticle platform.     

pH敏感型热休克笼形蛋白纳米载体的构建及其理化性质评价

目的 设计并制备具有靶向肿瘤且pH敏感的热休克蛋白（heat shock proteins,HSP）笼形蛋白纳米递药系统,并对其理化性质进行表征。方法 采用基因全合成与蛋白质重组表达技术纯化HSP为母版,通过表面官能团功能化制备得到修饰穿膜肽Tat、聚乙二醇包衣的热休克笼形蛋白纳米载体（PT-HSP）。通过透射电镜、纳米粒度与Zeta电位测定仪对其形态、粒径及Zeta电位进行表征,并建立HPLC测定其载药量与包封率。考察载紫杉醇（paclitaxel,PTX）的PT-HSP在生理pH条件（pH 7.4）与肿瘤pH条件（pH 6.5）下的体外释药行为。结果 形态学结果表明,PT-HSP是呈现典型双层结构的均一球体,平均粒径为（154.4±23.6） nm,Zeta电位为（-2.6±0.7） mV。HPLC测得载PTX的PT-HSP的包封率为（75.3±3.6）%,载药量为（7.0±0.2）%。体外释药试验结果表明PT-HSP在pH 7.4条件下的释放速率显著慢于pH 6.5条件下的释放速率（P<0.01）。结论 本研究制备得到的pH敏感的HSP笼形蛋白智能纳米递药系统具有载药量高、稳定性强及智能靶向等优点,有望成为一种安全、有效、智能的抗肿瘤药物载体。     

维生素类药物在肿瘤治疗中的应用

综述维生素类药物的抗肿瘤作用机制和药理作用以及在肿瘤靶向给药系统中的应用。维生素及其衍生物不仅具有良好的抗肿瘤活性和毒副作用小的特点，且有独特的肿瘤靶向性，如叶酸和生物素，其应用于肿瘤靶向给药系统，可大大提高药物疗效及减小药物毒副作用。