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。     

智能响应型介孔二氧化硅抗肿瘤纳米递药系统的设计策略与研究应用

恶性肿瘤是危害人类健康的重大疾病,由于其微环境复杂多变,导致大多数抗肿瘤药物不能精准地到达病灶组织并可控释放。智能响应型纳米载体已成为抗肿瘤递药系统研究领域的热点。介孔二氧化硅作为一种优良的纳米材料,具有无毒、稳定、孔容孔径可调及表面易于功能化修饰等优势,凭借其对机体肿瘤微环境或生理变化的感知响应、实现递药系统在病灶组织定位释药或控制释药,使其成为智能响应型递药系统的理想载体。本文基于介孔二氧化硅的智能响应型递药系统的设计策略及研究应用展开综述,以期为抗肿瘤药物纳米制剂的研发提供参考。     

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。     

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。     

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。     

经鼻递脑机制及基于EPR效应的脑靶向脂质体的研究进展

鼻腔与脑在解剖生理结构上的独特联系使得鼻腔给药作为脑内递药途径成为可能,而作为特殊给药系统的脂质体具有鼻腔给药的诸多特点,经鼻腔给药并且利用肿瘤的长滞留效应（EPR效应）或"炎症靶向"达到脑靶向作用,可增加药物的脑内递送。近年来经鼻递药结合EPR效应的策略越来越受到关注,本文归纳总结了近些年国内外有关经鼻递脑途径的机制、影响因素,探讨了经鼻给药结合EPR效应的脑靶向脂质体在中枢神经系统疾病方面的相关研究。     

纳米递药系统在三阴性乳腺癌综合靶向治疗中的应用

高度恶性肿瘤三阴性乳腺癌的治疗局限在于肿瘤细胞耐药性克隆的形成和化疗药物常规给药对正常组织的严重毒性。近年来研究显示,三阴性乳腺癌综合靶向治疗中,纳米递药系统借助纳米材料独具的理化性质,负载化疗药物、活性基因片段和免疫增强因子等,通过光热消融效应、化疗药物增效减毒作用、抑制肿瘤增殖基因作用和免疫系统激活作用,有效抑制和杀灭肿瘤细胞。纳米递药系统改变了常规化疗药物药动学特性,明显减轻药物的不良反应。本文就纳米递药系统在三阴性乳腺癌综合靶向治疗中研究进展做一简要综述。     

经鼻脑靶向递药系统的研究进展

鼻腔与脑在解剖生理上的独特联系使得鼻腔给药作为脑内递药途径成为可能.鼻腔给药作为脑靶向的途径之一,可有效地使通过其他给药途径不易透过血脑屏障的药物绕过血脑屏障到达脑部,为中枢神经系统疾病的治疗提供了一种极有发展前景的脑内递药途径.就鼻腔给药脑靶向的依据、影响因素、评价方法、剂型等方面对经鼻脑靶向递药系统的研究现状进行总结.     

肿瘤靶向给药系统的临床应用进展

目的对抗肿瘤靶向给药系统的研究进展作一简介。方法检索近年国内外有关对靶向给药系统在肿瘤治疗中的研究性文献,并进行分析、归纳,综述肿瘤组织靶向、肿瘤细胞靶向、肿瘤血管靶向等给药系统及肿瘤靶向治疗基因给药系统的研究进展,以完善现有肿瘤的靶向治疗。结果靶向药物制剂能使药物选择性地与靶组织在细胞或亚细胞水平上发生反应,使药物能够可控性地分布,并于靶区持续缓慢地释放药物,降低其对正常组织的不良反应。结论靶向制剂对于克服肿瘤治疗中的不良反应,提高疗效具有不可忽视的作用,但它们广泛应用于临床尚需时日。     

Advances in hydrogels applied to degenerative diseases

Hydrogels are currently applied in the treatment of numerous degenerative diseases because of their three dimensional (3D) nature, high water content and wide range of polymers that can be used for their fabrication. Hydrogels have been investigated and commercialized, for example, as soft contact lens-based ophthalmic drug delivery systems. These novel devices improved the bioavailability of ophthalmic drugs and their residence time. Hydrogels are also being investigated to facilitate and augment targeted delivery of chemotherapeutic agents. This approach minimizes significantly the side effects associated with conventional administration of anti-cancer therapeutics. The application of hydrogels as 3D scaffold has recently gained momentum because they can mimic key features of the extracellular matrix. For this reason, hydrogels are representing a viable alternative to traditional tumor xenograft in cancer biology studies. This review highlights recent advances in the development of hydrogels that are applied in degenerative diseases such as ocular, cancer, spine and cartilage degenerative pathologies.     

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.     

Recent advances in bacterial therapeutics based on sense and response

Intelligent drug delivery is a promising strategy for cancer therapies. In recent years, with the rapid development of synthetic biology, some properties of bacteria, such as gene operability, excellent tumor colonization ability, and host-independent structure, make them ideal intelligent drug carriers and have attracted extensive attention. By implanting condition-responsive elements or gene circuits into bacteria, they can synthesize or release drugs by sensing stimuli. Therefore, compared with traditional drug delivery, the usage of bacteria for drug loading has better targeting ability and controllability, and can cope with the complex delivery environment of the body to achieve the intelligent delivery of drugs. This review mainly introduces the development of bacterial-based drug delivery carriers, including mechanisms of bacterial targeting to tumor colonization, gene deletions or mutations, environment-responsive elements, and gene circuits. Meanwhile, we summarize the challenges and prospects faced by bacteria in clinical research, and hope to provide ideas for clinical translation.     

Advancement of cell-penetrating peptides in combating triple-negative breast cancer

Extensive research efforts have been made and are still ongoing in the search for an ideal anti-cancer therapy. Almost all chemotherapeutics require a carrier or vehicle, a drug delivery system that can transport the drug specifically to the targeted cancer cells, sparing normal cells. Cell-penetrating peptides (CPPs) provide an effective and efficient pathway for the intra-cellular transportation of various bioactive molecules in several biomedical therapies. They are now well-recognized as facilitators of intracellular cargo delivery and have excellent potential for targeted anti-cancer therapy. In this review, we explain CPPs, recent progress in the development of new CPPs, and their utilization to transport cargoes such as imaging agents, chemotherapeutics, and short-interfering RNAs (siRNA) into tumor cells, contributing to the advancement of novel tumor-specific delivery systems.     

Cancer-targeted polymeric drugs

A major challenge in cancer chemotherapy is the selective delivery of small molecule anti cancer agents to tumor cells. Water-soluble polymer-drug conjugates exhibit good water solubility, increased half-life, and potent anti tumor effects. By localizing the drug at the desired site of action, macromolecular therapeutics have improved efficacy and enhanced safety at lower doses. Since small molecule drugs and macromolecular drugs enter cells by different pathways, multi-drug resistance (MDR) can be minimized. Anti-cancer polymer-drug conjugates can be divided into two targeting modalities: passive and active. Tumor tissues have anatomic characteristics that differ from normal tissues. Macromolecules penetrate and accumulate preferentially in tumors relative to normal tissues, leading to extended pharmacological effects. This "enhanced permeability and retention" (EPR) effect is the principal reason for current successes with macromolecular anti-cancer drugs. Both natural and synthetic polymers have been used as drug carriers, and several bioconjugates have been clinically approved or are in human clinical trials. While clinically useful anti-tumor activity has been achieved using passive macromolecular drug delivery systems, further selectivity is possible by active targeting. Attachment of targeting moieties to the polymer backbone can further exploit differences between cancer and normal cells through selective receptor-mediated endocytosis. This strategy would augment the EPR effect, thereby further improving the therapeutic index of the macromolecular drug. This review discusses the development and therapeutic potential of prototype macromolecular drugs for use in cancer chemotherapy. Specific examples are selected to illustrate the basic design principles for soluble polymeric drug delivery systems.     

Liposomes as targeted drug delivery systems in the treatment of breast cancer

Solid tumors such as breast cancer have historically provided many challenges to anti-cancer therapy. Therapeutic hurdles to drug penetration in solid tumors include heterogeneous vascular supply and high interstitial pressures within tumor tissue, particularly in necrotic zones, lower pH and presence of leaky vasculature leading to reduced therapeutic response. Liposome based drug delivery systems offer the potential to enhance the therapeutic index of anti-cancer agents, either by increasing the drug concentration in tumor cells and/or by decreasing the exposure in normal tissues exploiting enhanced permeability and retention effect phenomenon and by utilizing targeting strategies. This review discusses recent trends in liposome-based drug delivery system both for diagnosis and treatment of breast cancer.     

Liposomes as targeted drug delivery systems in the treatment of breast cancer

Solid tumors such as breast cancer have historically provided many challenges to anti-cancer therapy. Therapeutic hurdles to drug penetration in solid tumors include heterogeneous vascular supply and high interstitial pressures within tumor tissue, particularly in necrotic zones, lower pH and presence of leaky vasculature leading to reduced therapeutic response. Liposome based drug delivery systems offer the potential to enhance the therapeutic index of anti-cancer agents, either by increasing the drug concentration in tumor cells and/or by decreasing the exposure in normal tissues exploiting enhanced permeability and retention effect phenomenon and by utilizing targeting strategies. This review discusses recent trends in liposome-based drug delivery system both for diagnosis and treatment of breast cancer.     

pH响应性聚合物胶束及其在抗癌药物给药系统中的研究进展

 聚合物纳米粒作为一种有效的药物运送载体已经受到广泛的关注,具有环境响应性的聚合物胶束的制备及应用是目前引人瞩目的研究方向。最近,pH响应性聚合物胶束已被用作抗癌药物的运送载体,其显著的优势就是能够靶向给药于病灶部位,从而降低不良反应,提高抗癌药物的化疗指数。文中综述了pH值响应性的聚合物胶束的两种主要制备策略,即依赖于共聚物骨架中的“可滴定”基团;引入可被酸降解的连接臂,还介绍了pH值响应性聚合物胶束在抗癌药物给药系统中的应用。     

Tumour-specific uptake of anti-cancer drugs: the future is here

A challenge of anti-cancer treatment is the specific delivery of the drugs in order to avoid deleterious effects on normal cells. In fact, anti-cancer drugs have potent effects also on normal cells due to the strong similarity of the mechanisms of growth regulation of normal cells if compared to their transformed counterparts. The recent developments in nanotechnology allow the old Ehrlich's dream to deliver anti-cancer drugs in tumour tissue through their encapsulation in drug delivery systems (DDS). In the present review we analyze the different reasons to encapsulate an anti-tumour drug in DDS including eventual damages induced by their extravasation or by eccipients used to their solubilisation, the rapid break-down of the drug in vivo and the specific bio-distribution of the drug in tumour tissues. The delivery strategies of anti-cancer drugs are based upon the particular structure of tumour neo-angiogenic vessels that allow the passive targeting or enhanced permeability and retention (EPR). In order to avoid the entrapping of DDS in reticulo-endothelial system the nanoparticles can be modified with the addition on their surface of inert polyetilenglicole (PEG) molecules that inhibit the opsonisation of DDS by macrophages. The addition of targeting moieties, antibodies or Fab fragments or small peptides and aptamers, on the surface of DDS can allow the active targeting of DDS to tumour cells. In conclusion, a new avenue in anti-cancer treatment has been disclosed with the use of DDS.     

Emerging potential of stimulus-responsive nanosized anticancer drug delivery systems for systemic applications

The development of novel drug delivery systems based on well-defined polymer therapeutics has led to significant improvements in the treatment of multiple disorders. Advances in material chemistry, nanotechnology, and nanomedicine have revolutionized the practices of drug delivery. Stimulus-responsive material-based nanosized drug delivery systems have remarkable properties that allow them to circumvent biological barriers and achieve targeted intracellular drug delivery. Specifically, the development of novel nanocarrier-based therapeutics is the need of the hour in managing complex diseases. In this review, we have briefly described the fundamentals of drug targeting to diseased tissues, physiological barriers in the human body, and the mechanisms/modes of drug-loaded carrier systems. To that end, this review serves as a comprehensive overview of the recent developments in stimulus-responsive drug delivery systems, with focus on their potential applications and impact on the future of drug delivery.