Highlights • Recent trends in prodrug-based nanocarriers for cancer therapy are provided. • Stimuli-sensitive nanoparticulate drug delivery systems (Nano-DDS) facilitates the spatio-temporally ...controlled release of drugs. • Hybrid Nano-DDS is a potent multifunctional platform to deliver anticancer drugs. • Combination therapy can improve the therapeutic effects of prodrug-based Nano-DDS.
In the field of biomedicine, stimuli-responsive drug delivery systems (DDSs) have become increasingly popular due to their site-specific release ability in response to a certain physiological ...stimulus, which may result in both enhanced treatment outcome and reduced side effects. Reactive oxygen species (ROS) are the unavoidable consequence of cell oxidative metabolism. ROS play a crucial part in regulating biological and physiological processes, whereas excessive intracellular ROS usually lead to the oxidation stress which has implications in several typical diseases such as cancer, inflammation and atherosclerosis. Therefore, ROS-responsive DDSs have elicited widespread popularity for their promising applications in a series of biomedical research because the payload is only released in targeted cells or tissues that overproduce ROS. According to the design of ROS-responsive DDSs, the main release mechanisms of therapeutic agents can be ascribed to ROS-induced carrier solubility change, ROS-induced carrier cleavage or ROS-induced prodrug linker cleavage. This review summarized the latest development and novel design of ROS-responsive DDSs and discussed their design concepts and the applications in the biomedical field.
Unsaturated fatty acids (UFAs), with the distinct advantages of good biocompatibility and innate tumor-targeting effect, have been widely investigated for the rational design of chemotherapy ...agent-unsaturated fatty acid (CA-UFA) prodrugs in cancer therapy. Among them, several CA-UFA prodrugs have successfully entered clinical trials and are promising prospects for potential clinical applications. In addition, CA-UFA prodrug-based nanoparticulate drug delivery systems (nano-DDS), which integrate the advantages of CA-UFA prodrugs and nano-DDS, have been emerging as versatile nano-carriers for the efficient delivery of chemotherapeutics. In this paper, we review the advanced drug delivery strategies based on UFA conjugates and focus on the recent advances in CA-UFA prodrugs and the emerging CA-UFA prodrug-based nano-DDS. First, we discuss the rational design of CA-UFA prodrugs in response to the multiple obstacles in chemotherapy, with particular emphasis on the latest progress in both preclinical studies and clinical trials. Moreover, the emerging CA-UFA prodrug-based nano-DDS are also addressed. Finally, the prospects and potential challenges of CA-UFA prodrug-based drug delivery strategies in chemotherapy are highlighted.
Chemotherapy agent-unsaturated fatty acid (CA-UFA) prodrugs-based drug delivery strategies show distinct advantages in cancer chemotherapy. Display omitted
Nanomedicines employ multiple endocytic pathways to enter cells. Their following fate is interesting, but it is not sufficient understood currently. This review introduces the endocytic pathways, ...presents new technologies to confirm the specific endocytic pathways and discusses factors for pathway selection. In addition, some intriguing implication about nanomedicine design based on endocytosis will also be discussed at the end. This review may provide new thoughts for the design of novel multifunctional nanomedicines.
Cancer immunotherapy has become a new generation of anti-tumor treatment, but its indications still focus on several types of tumors that are sensitive to the immune system. Therefore, effective ...strategies that can expand its indications and enhance its efficiency become the key element for the further development of cancer immunotherapy. Natural products are reported to have this effect on cancer immunotherapy, including cancer vaccines, immune-check points inhibitors, and adoptive immune-cells therapy. And the mechanism of that is mainly attributed to the remodeling of the tumor-immunosuppressive microenvironment, which is the key factor that assists tumor to avoid the recognition and attack from immune system and cancer immunotherapy. Therefore, this review summarizes and concludes the natural products that reportedly improve cancer immunotherapy and investigates the mechanism. And we found that saponins, polysaccharides, and flavonoids are mainly three categories of natural products, which reflected significant effects combined with cancer immunotherapy through reversing the tumor-immunosuppressive microenvironment. Besides, this review also collected the studies about nano-technology used to improve the disadvantages of natural products. All of these studies showed the great potential of natural products in cancer immunotherapy.
Natural products can effectively enhance the therapeutic outcome and expand indications of cancer immunotherapies, including cancer vaccines, immune-checkpoint inhibitors, and adoptive immune-cells transfer therapy, through remodeling tumor immunosuppressive microenvironment. Display omitted
Highlights
Introducing mechanisms of antitumor activation produced by bacteria-mediated bio-therapy in detail.
Comprehensively reviewing multiple administration routes of bacterial bio-therapy in ...combination with different traditional anticancer therapeutic modalities over the recent 5 years.
Discussing the potential benefits and challenges of this anticancer approach, and conveying the development tendency and the application prospect of this field.
The use of bacteria to specifically migrate to cancerous tissue and elicit an antitumor immune response provides a promising platform against cancer with significantly high potency. With dozens of clinical trials underway, some researchers hold the following views: “humans are nearing the first commercial live bacteria therapeutic.” However, the facultative anaerobe
Salmonella typhimurium
VNP20009, which is particularly safe and shows anticancer effects in preclinical studies, had failed in a phase I clinical trial due to low tumor regression and undesired dose-dependent side effects. This is almost certain to disappoint people’s inflated expectations, but it is noted that recent state-of-the-art research has turned attention to bacteria-mediated synergistic cancer therapy (BMSCT). In this review, the foundation of bacteria-mediated bio-therapy is outlined. Then, we summarize the potential benefits and challenges of bacterial bio-therapy in combination with different traditional anticancer therapeutic modalities (chemotherapy, photothermal therapy, reactive oxygen and nitrogen species therapy, immunotherapy, or prodrug-activating therapy) in the past 5 years. Next, we discuss multiple administration routes of BMSCT, highlighting potentiated antitumor responses and avoidance of potential side effects. Finally, we envision the opportunities and challenges for BMSCT development, with the purpose of inspiring medicinal scientists to widely utilize the microbiome approach in patient populations.
Tumor cells are characterized as redox-heterogeneous intracellular microenvironment due to the simultaneous overproduction of reactive oxygen species and glutathione. Rational design of ...redox-responsive drug delivery systems is a promising prospect for efficient cancer therapy. Herein, six paclitaxel-citronellol conjugates are synthesized using either thioether bond, disulfide bond, selenoether bond, diselenide bond, carbon bond or carbon-carbon bond as linkages. These prodrugs can self-assemble into uniform nanoparticles with ultrahigh drug-loading capacity. Interestingly, sulfur/selenium/carbon bonds significantly affect the efficiency of prodrug nanoassemblies. The bond angles/dihedral angles impact the self-assembly, stability and pharmacokinetics. The redox-responsivity of sulfur/selenium/carbon bonds has remarkable influence on drug release and cytotoxicity. Moreover, selenoether/diselenide bond possess unique ability to produce reactive oxygen species, which further improve the cytotoxicity of these prodrugs. Our findings give deep insight into the impact of chemical linkages on prodrug nanoassemblies and provide strategies to the rational design of redox-responsive drug delivery systems for cancer therapy.
Breast cancer contributes to high mortality rates as a result of metastasis. Tumor-derived exosomes facilitate the development of the premetastatic environment, interacting and inhibiting the normal ...function of immune cells, thereby forming an immunosuppressive microenvironment for tumor metastasis. Herein, the platelet and neutrophil hybrid cell membrane (PNM) was embellished on a gold nanocage (AuNC) surface called nanosponges and nanokillers (NSKs). NSKs can simultaneously capture and clear the circulating tumor cells (CTCs) and tumor-derived exosomes via high-affinity membrane adhesion receptors, effectively cutting off the connection between exosomes and immune cells. Bionic NSK is loaded with doxorubicin (DOX) and indocyanine green (ICG) for synergic chemo-photothermal therapy. NSKs show greater cellular uptake, deeper tumor penetration, and higher cytotoxicity to tumor cells in comparison to non-coated AuNCs or single-coated AuNCs in vitro. In vivo, the multipurpose NSKs could not only completely ablate the primary tumor but also inhibit breast cancer metastasis with high efficiency in xenograft and orthotopic breast tumor-bearing models. Thus, NSKs could be a promising nanomedicine for the future clinical intervention of breast cancer metastasis.
Targeted nano-drug delivery systems conjugated with specific ligands to target selective cell-surface receptors or transporters could enhance the efficacy of drug delivery and therapy. Transporters ...are expressed differentially on the cell-surface of different cell types, and also specific transporters are expressed at higher than normal levels in selective cell types under pathological conditions. They also play a key role in intestinal absorption, delivery via non-oral routes (e.g., pulmonary route and nasal route), and transfer across biological barriers (e.g., blood-brain barrier and blood-retinal barrier. As such, the cell-surface transporters represent ideal targets for nano-drug delivery systems to facilitate drug delivery to selective cell types under normal or pathological conditions and also to avoid off-target adverse side effects of the drugs. There is increasing evidence in recent years supporting the utility of cell-surface transporters in the field of nano-drug delivery to increase oral bioavailability, to improve transfer across the blood-brain barrier, and to enhance delivery of therapeutics in a cell-type selective manner in disease states. Here we provide a comprehensive review of recent advancements in this interesting and important area. We also highlight certain key aspects that need to be taken into account for optimal development of transporter-assisted nano-drug delivery systems.
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