Subcellular co-delivery of two different site-oriented payloads based on multistage targeted polymeric nanoparticles for enhanced cancer therapy

Nanodrugs based on co-delivery strategies to combat cisplatin resistance

Cisplatin (CDDP), as a broad-spectrum anticancer drug, is able to bind to DNA and inhibit cell division. Despite the widespread use of cisplatin since its discovery, cisplatin resistance developed during prolonged chemotherapy, similar to other small molecule chemotherapeutic agents, severely limits its clinical application. Cisplatin resistance in cancer cells is mainly caused by three reasons: DNA repair, decreased cisplatin uptake/increased efflux, and cisplatin inactivation. In earlier combination therapies, the emergence of multidrug resistance (MDR) in cancer cells prevented the achievement of the desired therapeutic effect even with the accurate combination of two chemotherapeutic drugs. Therefore, combination therapy using nanocarriers for co-delivery of drugs is considered to be ideal for alleviating cisplatin resistance and reducing cisplatin-related toxicity in cancer cells. This article provides an overview of the design of cisplatin nano-drugs used to combat cancer cell resistance, elucidates the mechanisms of action of cisplatin and the pathways through which cancer cells develop resistance, and finally discusses the design of drugs and related carriers that can synergistically reduce cancer resistance when combined with cisplatin.

The development and evaluation of hyaluronic acid coated mitochondrial targeting liposomes for celastrol delivery

In order to precisely deliver celastrol into mitochondria of tumor cells, improve antitumor efficacy of celastrol and overcome its troublesome problems in clinical application, a novel multistage-targeted celastrol delivery system (C-TL/HA) was developed via electrostatic binding of hyaluronic acid (HA) to celastrol-loaded cationic liposomes composed of natural soybean phosphatidylcholine and cholesterol modified with mitochondrial targeting molecular TPP. Study results in this article showed that C-TL/HA successfully transported celastrol into mitochondria, effectively activated apoptosis of mitochondrial pathway, exerted higher tumor inhibition efficiency and lower toxic side effects compared with free celastrol. More importantly, HA coating not only enabled this delivery system to have good stability and safety in vivo, but also increased drug uptake and facilitated tumor targeting through recognizing CD44 receptors rich on the surface of tumor cells. Conclusively, this HA-coated mitochondrial targeting liposomes may provide a prospect for the clinical application of celastrol in tumor therapy.

Research progress in nucleus-targeted tumor therapy

The nucleus is considered the most important organelle in the cell as it plays a central role in controlling cell reproduction, metabolism, and the cell cycle. The successful delivery of drugs into the nucleus can achieve excellent therapeutic effects, which reveals the potential of nucleus-targeted therapy in precision medicine. However, the transportation of therapeutics into the nucleus remains a significant challenge due to various biological barriers. Herein, we summarize the recent progress in the nucleus-targeted drug delivery system (NDDS). The structures of the nucleus and nuclear envelope are first described in order to understand the mechanisms by which drugs cross the nuclear envelope. Then, various drug delivery strategies based on the mechanisms and their applications are discussed. Finally, the challenges and solutions in the field of nucleus-targeted drug delivery are raised for developing a more efficient NDDS and promoting its clinical transformation.

Nanocarriers for intracellular co-delivery of proteins and small-molecule drugs for cancer therapy

In the past few decades, the combination of proteins and small-molecule drugs has made tremendous progress in cancer treatment, but it is still not satisfactory. Because there are great differences in molecular weight, water solubility, stability, pharmacokinetics, biodistribution, and the ways of release and action between macromolecular proteins and small-molecule drugs. To improve the efficacy and safety of tumor treatment, people are committed to developing protein and drug co-delivery systems. Currently, intracellular co-delivery systems have been developed that integrate proteins and small-molecule drugs into one nanocarrier via various loading strategies. These systems significantly improve the blood stability, half-life, and biodistribution of proteins and small-molecule drugs, thus increasing their concentration in tumors. Furthermore, proteins and small-molecule drugs within these systems can be specifically targeted to tumor cells, and are released to perform functions after entering tumor cells simultaneously, resulting in improved effectiveness and safety of tumor treatment. This review summarizes the latest progress in protein and small-molecule drug intracellular co-delivery systems, with emphasis on the composition of nanocarriers, as well as on the loading methods of proteins and small-molecule drugs that play a role in cells into the systems, which have not been summarized by others so far.

Multifunctional Mitochondria-Targeting Nanosystems for Enhanced Anticancer Efficacy

Mitochondria, a kind of subcellular organelle, play crucial roles in cancer cells as an energy source and as a generator of reactive substrates, which concern the generation, proliferation, drug resistance, and other functions of cancer. Therefore, precise delivery of anticancer agents to mitochondria can be a novel strategy for enhanced cancer treatment. Mitochondria have a four-layer structure with a high negative potential, which thereby prevents many molecules from reaching the mitochondria. Luckily, the advances in nanosystems have provided enormous hope to overcome this challenge. These nanosystems include liposomes, nanoparticles, and nanomicelles. Here, we summarize the very latest developments in mitochondria-targeting nanomedicines in cancer treatment as well as focus on designing multifunctional mitochondria-targeting nanosystems based on the latest nanotechnology.

Glutathione-triggered nanoplatform for chemodynamic/metal-ion therapy

The integration of metal-ion therapy and hydroxyl radical (˙OH)-mediated chemodynamic therapy (CDT) holds great potential for anticancer treatment with high specificity and efficiency. Herein, Ag nanoparticles (Ag NPs) were enveloped with Cu²⁺-based metal-organic frameworks (MOFs) and further decorated with hyaluronic acid (HA) to construct a glutathione (GSH)-activated nanoplatform (Ag@HKU-HA) for specific chemodynamic/metal-ion therapy. The obtained nanoplatform could avoid the premature leakage of Ag in circulation, but realize the release of Ag at the tumor site owing to the degradation of external MOFs triggered by Cu²⁺-reduced glutathione. The generated Cu⁺ could catalyze endogenous H₂O₂ to the highly toxic ˙OH by a Fenton-like reaction. Meanwhile, Ag NPs were oxidized to toxic Ag ions in the tumor environment. As expect, the effect of CDT combined with metal-ion therapy exhibited an excellent inhibition of tumor cells growth. Therefore, this nanoplatform may provide a promising strategy for on-demand site-specific cancer combination treatment.

An understanding of mitochondria and its role in targeting nanocarriers for diagnosis and treatment of cancer

Nanotechnology has changed the entire paradigm of drug targeting and has shown tremendous potential in the area of cancer therapy due to its specificity. In cancer, several targets have been explored which could be utilized for the better treatment of disease. Mitochondria, the so-called powerhouse of cell, portrays significant role in the survival and death of cells, and has emerged as potential target for cancer therapy. Direct targeting and nanotechnology based approaches can be tailor-made to target mitochondria and thus improve the survival rate of patients suffering from cancer. With this backdrop, in present review, we have reemphasized the role of mitochondria in cancer progression and inhibition, highlighting the different targets that can be explored for targeting of disease. Moreover, we have also summarized different nanoparticulate systems that have been used for treatment of cancer via mitochondrial targeting.

Recent advances in ionic liquids and nanotechnology for drug delivery

In drug discovery and drug development, it is estimated that around 40% of commercialized and 90% of under-study drugs have inadequate pharmaceutical properties, severely impairing its therapeutic efficacy. Thus, there is a strong demand to find strategies to enhance the delivery of such drugs. Ionic liquids are a novel class of liquids composed of a combination of organic salts that are of particular interest alone or in combination with drug delivery systems. This review is focused on the recent efforts using ionic liquids in drug solubility, formulation and drug delivery with specific emphasis on nanotechnology. The latest developments using hybrid delivery systems obtained upon the combination of drug delivery systems and ionic liquids will also be addressed.

A novel progress of drug delivery system for organelle targeting in tumour cells

At present, malignant tumours have become one of the most serious diseases that endanger human health. According to a survey on causes of death in Chinese population in early 1990s, the malignant tumours were the second leading cause of death. In the treatment of tumours, the ideal situation is that drugs should target and accumulate at tumour sites and destroy tumour cells specifically, without affecting normal cells and stem cells with regenerative capacity. This requires drugs to be specifically transported to the target organs, tissues, cells, and even specific organelles, like mitochondria, nuclei, lysosomes, endoplasmic reticulum (ER), and Golgi apparatus (GA). The nano drug delivery system can not only protect drugs from degradation but also facilitate functional modification and targeted drug delivery to the tumour site. This article mainly reviews the targeting of nano drug delivery systems to tumour cytoplasmic matrix, nucleus, mitochondria, ER, and lysosomes. Organelle-specific drug delivery system will be a major mean of targeting drug delivery with lower toxicity, less dosage and higher drug concentration in tumour cells.

Dendritic Mesoporous Organosilica Nanoparticles: A pH-Triggered Autocatalytic Fenton Reaction System with Self-supplied H2O2 for Generation of High Levels of Reactive Oxygen Species

Dendritic mesoporous silica nanoparticles represent a new biomedical application platform due to their special central radial pore structure for the loading of drugs and functional modification. Herein, we report functionalized dendritic mesoporous organosilica nanoparticles (DMONs), a pH-triggered Fenton reaction generator (TA/Fe@GOD@DMONs), incorporating natural glucose oxidase (GOD) in the DMONs with tannic acid (TA) grafted using Fe³⁺ on the surface, that have been designed and constructed for efficient tumor ablation with self-supplied H₂O₂ and accelerated conversion of Fe³⁺/Fe²⁺ by TA. In view of the deficiency of endogenous H₂O₂, the self-supply through the TA/Fe@GOD@DMONs platform represented a high-yielding source of peroxygen. Furthermore, the production of Fe²⁺ induced by TA greatly improved the efficiency of the Fenton reaction resulting in significant tumor inhibition. This new design represents as novel paradigm for the development of autocatalytic Fenton nanosystems for effective treatment of tumors.

Low-Temperature Trigger Nitric Oxide Nanogenerators for Enhanced Mild Photothermal Therapy

Surmounting the restriction issues of nitric oxide (NO) delivery to realize their precious on-demand release is highly beneficial for the widespread deployment of gas therapy for application in biomedicine. Herein, by employing core-shell structure Au@SiO₂ nanomaterials with high photothermal performance, a novel strategy was proposed by integrating photothermal conversion nanomaterials and heat-triggered NO donors (RSNO) into a nanoplatform, which achieved photothermal therapy (PTT)-enhanced NO gas therapy under near-infrared (NIR) radiation. Specifically, 2-phenylethynesulfonamide (PES), an inhibitor of heat shock protein 70 (HSP-70), was loaded into the NO nanogenerators to realize effective low-temperature (∼45 °C) PTT. The obtained results showed that the near-infrared radiation (NIR) mediated mild PTT and gas therapy by releasing NO showed a substantially improved synergistic effect based on in vitro and in vivo results in breast cancer (MCF-7) models. Our study points out a strategy to realize mild photothermal therapy by inhibiting the expression of HSP-70 and simultaneously providing an avenue to achieve controllable release of NO. More important, this research highlights the great potential of multifunctional therapeutic agents in the synergistic treatment of cancer.

A novel versatile yolk-shell nanosystem based on NIR-elevated drug release and GSH depletion-enhanced Fenton-like reaction for synergistic cancer therapy

In this study, a versatile doxorubicin (DOX)-loaded yolk-shell nano-particles (HMCMD) assembled with manganese dioxide (MnO₂) as the core and copper sulfide (HMCuS) as the mesoporous (∼ 6.4 nm) shell, was designed and synthesized. The resulting HMCMD possess excellent photothermal conversion efficiency. The DOX release from the yolk-shell nanoparticles could be promoted by laser irradiation, which increased the chemotherapy of DOX. Meanwhile, Mn²⁺ could be released from the HMCMD through a redox reaction between MnO₂ and abundant glutathione (GSH) in tumor cells. The released Mn²⁺ could promote the decomposition of the intracellular hydrogen peroxide (H₂O₂) by Fenton-like reaction to generate the highly toxic hydroxyl radicals (·OH), thus exhibiting the effective chemodynamic therapy (CDT). Additionally, the efficiency of Mn²⁺-mediated CDT could be effectively enhanced by NIR irradiation. Further modification of polyethylene glycol (PEG) would improve the water solubility of the HMCMD to promote the uptake by MCF-7 cells. Hence, the HMCMD with synergistic effects of chemotherapy and chemodynamic/photothermal therapy would provide an alternative strategy in antitumor research.

Multimodal therapies: glucose oxidase-triggered tumor starvation-induced synergism with enhanced chemodynamic therapy and chemotherapy

A tumor microenvironment is distinct from normal tissue cells in characteristic physiochemical conditions, based on which we can design tumor-specific therapy modalities.

Cetuximab-modified silica nanoparticle loaded with ICG for tumor-targeted combinational therapy of breast cancer

Combinational therapy is usually considered as a preferable approach for effective cancer therapy. Especially, combinational chemo and photothermal therapy is of particular interest due to its high flexibility as well as efficiency. In this article, we the silica nanoparticles (SLN) were surface conjugated with Cetuximab (Cet-SLN) to target epidermal growth factor receptor (EGFR), a common receptor that usually observed to overexpress in multiple breast cancers. Moreover, the high drug loading capacity of Cet-SLN was employed to encapsulate photothermal agent indocyanine green (ICG) to finally fabricate a versatile drug delivery system (DDS) able to co-deliver Cet and ICG (Cet-SLN/ICG) for combinational chemo-photothermal therapy of breast cancer. The obtained results clearly demonstrated that Cet-SLN/ICG was well-dispersed nanoparticles with preferable stability under physiological condition. Furthermore, due to the conjugation of Cet, Cet-SLN/ICG could target EGFR which overexpress in MCF-7 cells. Most importantly, both in vitro and in vivo results suggested that compared with Cet or ICG alone, the Cet-SLN/ICG showed superior anticancer efficacy. In conclusion, Cet-SLN/ICG could be a potential platform for effective combinational chemo-photothermal therapy for breast cancer.

Facile formulation of near-infrared light-triggered hollow mesoporous silica nanoparticles based on mitochondria targeting for on-demand chemo/photothermal/photodynamic therapy

The incorporation of chemo/photothermal/photodynamic therapy in subcellular organelles such as mitochondria has attracted extensive attention recently. Here, we designed mitochondria-targeted hollow mesoporous silica nanoparticles (THMSNs) loaded biocompatible phase-change material L-menthol (LM) via a facile method. Meanwhile, antitumor drug doxorubicin (DOX) and near-infrared (NIR) dye indocyanine green (ICG) approved by FDA were simultaneously encapsulated into THMSNs, denoted as THMSNs@LMDI, which showed NIR radiation triggered capacity for cancer treatment. With the mitochondria-targeted ability of triphenylphosphine, the resulting THMSNs@LMDI showed evidently improved cellular internalization and specific accumulation in mitochondria. Under NIR irradiation, the versatile ICG would be bound to simultaneously produce photodynamic and photothermal therapy. Meanwhile, in view of the solid-liquid phase transition feature of gatekeeper LM, THMSNs@LMDI provided a platform for NIR-mediated temperature-responsive DOX release. As a matter of course, these smart subcellular organelle-THMSNs could serve as an effective drug delivery platform for site-specific on-demand chemo/photothermal/photodynamic therapy of cancer.

A small-sized and stable 2D metal–organic framework: a functional nanoplatform for effective photodynamic therapy

A small-sized 2D metal–organic framework with remarkable ROS generation ability through enhanced intersystem crossing.

A novel pH-responsive hollow mesoporous silica nanoparticle (HMSN) system encapsulating doxorubicin (DOX) and glucose oxidase (GOX) for potential cancer treatment

The multi-therapy modality is based on the combination and synergy of multiple single treatment modalities and materials chemistry.

Reactive oxygen species mediated theranostics using a Fenton reaction activable lipo-polymersome

Recently, reactive oxygen species (ROS)-induced apoptosis has been widely studied by researchers through various means. Among them, the singlet oxygen produced by the Fenton reaction is particularly effective in killing tumor cells. Although photodynamic therapy (PDT) takes advantage of the spatial-temporal control of ROS production, the design of the Fenton reaction in an ingenious way is still a question worth exploring. Herein, we have designed and prepared a succinic peroxide-filled Fenton reaction activable Pt/Fe₃O₄@SP-PLGA lipo-polymersome that displays ROS mediated chemodynamic therapy (CDT). The therapeutic element, ˙OH, is generated under NIR irradiation/tumor acidic pH environment through engineering the reaction between succinic peroxide (SP) and iron oxide. Instead of using single endogenous H₂O₂ or even encapsulation, the conjugation with SP in the Pt/Fe₃O₄@SP-PLGA lipo-polymersome provides a more stable, high-yielding peroxygen source. The results also showed that after the addition of cisplatin, the amount of ROS production increased significantly. The proof-of-concept design of the Fenton reaction activable Pt/Fe₃O₄@SP-PLGA lipo-polymersome with enhanced ROS-generation characteristics provides a general approach to afford potent ROS-mediated cancer therapy.