An autonomous tumor-targeted nanoprodrug for reactive oxygen species-activatable dual-cytochrome c/doxorubicin antitumor therapy

Nano- and Micro-Platforms in Therapeutic Proteins Delivery for Cancer Therapy: Materials and Strategies

Proteins have emerged as promising therapeutics in oncology due to their great specificity. Many treatment strategies are developed based on protein biologics, such as immunotherapy, starvation therapy, and pro-apoptosis therapy, while some protein biologics have entered the clinics. However, clinical translation is severely impeded by instability, short circulation time, poor transmembrane transportation, and immunogenicity. Micro- and nano-particles-based drug delivery platforms are designed to solve those problems and enhance protein therapeutic efficacy. This review first summarizes the different types of therapeutic proteins in clinical and research stages, highlighting their administration limitations. Next, various types of micro- and nano-particles are described to demonstrate how they can overcome those limitations. The potential of micro- and nano-particles are then explored to enhance the therapeutic efficacy of proteins by combinational therapies. Finally, the challenges and future directions of protein biologics carriers are discussed for optimized protein delivery.

Challenges of enzyme therapy: Why two players are better than one

Enzyme-based therapy has garnered significant attention for its current applications in various diseases. Despite the notable advantages associated with the use of enzymes as therapeutic agents, that could have high selectivity, affinity, and specificity for the target, their application faces challenges linked to physico-chemical and pharmacological properties. These limitations can be addressed through the encapsulation of enzymes in nanoplatforms as a comprehensive solution to mitigate their degradation, loss of activity, off-target accumulation, and immunogenicity, thus enhancing bioavailability, therapeutic efficacy, and circulation time, thereby reducing the number of administrations, and ameliorating patient compliance. The exploration of novel nanomedicine-based enzyme therapeutics for the treatment of challenging diseases stands as a paramount goal in the contemporary scientific landscape, but even then it is often not enough. Combining an enzyme with another therapeutic (e.g., a small molecule, another enzyme or protein, a monoclonal antibody, or a nucleic acid) within a single nanocarrier provides innovative multidrug-integrated therapy and ensures that both the actives arrive at the target site and exert their therapeutic effect, leading to synergistic action and superior therapeutic efficacy. Moreover, this strategic approach could be extended to gene therapy, a field that nowadays has gained increasing attention, as enzymes acting at genomic level and nucleic acids may be combined for synergistic therapy. This multicomponent therapeutic approach opens opportunities for promising future developments. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Diverse functions of cytochrome c in cell death and disease

The redox-active protein cytochrome c is a highly positively charged hemoglobin that regulates cell fate decisions of life and death. Under normal physiological conditions, cytochrome c is localized in the mitochondrial intermembrane space, and its distribution can extend to the cytosol, nucleus, and extracellular space under specific pathological or stress-induced conditions. In the mitochondria, cytochrome c acts as an electron carrier in the electron transport chain, facilitating adenosine triphosphate synthesis, regulating cardiolipin peroxidation, and influencing reactive oxygen species dynamics. Upon cellular stress, it can be released into the cytosol, where it interacts with apoptotic peptidase activator 1 (APAF1) to form the apoptosome, initiating caspase-dependent apoptotic cell death. Additionally, following exposure to pro-apoptotic compounds, cytochrome c contributes to the survival of drug-tolerant persister cells. When translocated to the nucleus, it can induce chromatin condensation and disrupt nucleosome assembly. Upon its release into the extracellular space, cytochrome c may act as an immune mediator during cell death processes, highlighting its multifaceted role in cellular biology. In this review, we explore the diverse structural and functional aspects of cytochrome c in physiological and pathological responses. We summarize how posttranslational modifications of cytochrome c (e.g., phosphorylation, acetylation, tyrosine nitration, and oxidation), binding proteins (e.g., HIGD1A, CHCHD2, ITPR1, and nucleophosmin), and mutations (e.g., G41S, Y48H, and A51V) affect its function. Furthermore, we provide an overview of the latest advanced technologies utilized for detecting cytochrome c, along with potential therapeutic approaches related to this protein. These strategies hold tremendous promise in personalized health care, presenting opportunities for targeted interventions in a wide range of conditions, including neurodegenerative disorders, cardiovascular diseases, and cancer.

Exploring novel strategies to improve anti-tumour efficiency: The potential for targeting reactive oxygen species

The cellular milieu in which malignant growths or cancer stem cells reside is known as the tumour microenvironment (TME). It is the consequence of the interactivity amongst malignant and non-malignant cells and directly affects cancer development and progression. Reactive oxygen species (ROS) are chemically reactive molecules that contain oxygen, they are generated because of numerous endogenous and external factors. Endogenous ROS produced from mitochondria is known to significantly increase intracellular oxidative stress. In addition to playing a key role in several biological processes both in healthy and malignant cells, ROS function as secondary messengers in cell signalling. At low to moderate concentrations, ROS serves as signalling transducers to promote cancer cell motility, invasion, angiogenesis, and treatment resistance. At high concentrations, ROS can induce oxidative stress, leading to DNA damage, lipid peroxidation and protein oxidation. These effects can result in cell death or trigger signalling pathways that lead to apoptosis. The creation of innovative therapies and cancer management techniques has been aided by a thorough understanding of the TME. At present, surgery, chemotherapy, and radiotherapy, occasionally in combination, are the most often used methods for tumour treatment. The current challenge that these therapies face is the lack of spatiotemporal application specifically at the lesion which results in toxic effects on healthy cells associated with off-target drug delivery and undesirably high doses. Nanotechnology can be used to specifically deliver various chemicals via nanocarriers to target tumour cells, thereby increasing the accumulation of ROS-inducing agents at the site of the tumour. Nanoparticles can be engineered to release ROS-inducing agents in a controlled manner to the TME that will in turn react with the ROS to either increase or decrease it, thereby improving antitumour efficiency. Nano-delivery systems such as liposomes, nanocapsules, solid lipid nanoparticles and nanostructured lipid carriers were explored for the up/down-regulation of ROS. This review will discuss the use of nanotechnology in targeting and altering the ROS in the TME.

Click Chemistry Selectively Activates an Auristatin Protodrug with either Intratumoral or Systemic Tumor-Targeting Agents

The Click Activated Protodrugs Against Cancer (CAPAC) platform enables the activation of powerful cancer drugs at tumors. CAPAC utilizes a click chemistry reaction between tetrazine and trans-cyclooctene. The reaction between activator, linked to a tumor-targeting agent, and protodrug leads to the targeted activation of the drug. Here, tumor targeting is achieved by intratumoral injection of a tetrazine-modified hyaluronate (SQL70) or by infusion of a tetrazine-modified HER2-targeting antigen-binding fragment (SQT01). Monomethyl auristatin E (a cytotoxin hindered in its clinical use by severe toxicity) was modified with a trans-cyclooctene to form the protodrug SQP22, which reduced its cytotoxicity in vitro and in vivo. Treatment of SQP22 paired with SQL70 demonstrated antitumor effects in Karpas 299 and RENCA murine tumor models, establishing the requirement of click chemistry for protodrug activation. SQP22 paired with SQT01 induced antitumor effects in the HER2-positive NCI-N87 xenograft model, showing that tumor-targeted activation could be accomplished via systemic dosing. Observed toxicities were limited, with transient myelosuppression and moderate body weight loss detected. This study highlights the capabilities of the CAPAC platform by demonstrating the activity of SQP22 with two differentiated targeting approaches and underscores the power of click chemistry to precisely control the activation of drugs at tumors.

SQ3370, the first clinical click chemistry-activated cancer therapeutic, shows safety in humans and translatability across species

BACKGROUND

SQ3370 is the first demonstration of the Click Activated Protodrugs Against Cancer (CAPAC™) platform that uses click chemistry to activate drugs directly at tumor sites, maximizing therapeutic exposure. SQ3370 consists of a tumor-localizing biopolymer (SQL70) and a chemically-attenuated doxorubicin (Dox) protodrug SQP33; the protodrug is activated upon clicking with the biopolymer at tumor sites. Here, we present data from preclinical studies and a Phase 1 dose-escalation clinical trial in adult patients with advanced solid tumors ( NCT04106492 ) demonstrating SQ3370's activation at tumor sites, safety, systemic pharmacokinetics (PK), and immunological activity.

METHODS

Treatment cycles consisting of an intratumoral or subcutaneous injection of SQL70 biopolymer followed by 5 daily intravenous doses of SQP33 protodrug were evaluated in tumor-bearing mice, healthy dogs, and adult patients with solid tumors.

RESULTS

SQL70 effectively activated SQP33 at tumor sites, resulting in high Dox concentrations that were well tolerated and unachievable by conventional treatment. SQ3370 was safely administered at 8.9x the veterinary Dox dose in dogs and 12x the conventional Dox dose in patients, with no dose-limiting toxicity reported to date. SQ3370's safety, toxicology, and PK profiles were highly translatable across species. SQ3370 increased cytotoxic CD3 ⁺ and CD8 ⁺ T-cells in patient tumors indicating T-cell-dependent immune activation in the tumor microenvironment.

CONCLUSIONS

SQ3370, the initial demonstration of click chemistry in humans, enhances the safety of Dox at unprecedented doses and has the potential to increase therapeutic index. Consistent safety, toxicology, PK, and immune activation results observed with SQ3370 across species highlight the translatability of the click chemistry approach in drug development.

TRIAL REGISTRATION

NCT04106492; 7 September 2019.

An Antisense Oligonucleotide-Loaded Blood-Brain Barrier Penetrable Nanoparticle Mediating Recruitment of Endogenous Neural Stem Cells for the Treatment of Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by the death of dopaminergic (DA) neurons and currently cannot be cured. One selected antisense oligonucleotide (ASO) is reported to be effective for the treatment of PD. However, ASO is usually intrathecally administered by lumbar puncture into the cerebral spinal fluid, through which the risks of highly invasive neurosurgery are the major concerns. In this study, ZAAM, an ASO-loaded, aptamer Apt 19S-conjugated, neural stem cell membrane (NSCM)-coated nanoparticle (NP), was developed for the targeted treatment of PD. NSCM facilitated the blood-brain barrier (BBB) penetration of NPs, and both NSCM and Apt 19S promoted the recruitment of the neural stem cells (NSCs) toward the PD site for DA neuron regeneration. The behavioral tests demonstrated that ZAAM highly improved the efficacy of ASO on PD by the targeted delivery of ASO and the recruitment of NSCs. This work is a heuristic report of (1) nonchemoattractant induced endogenous NSC recruitment, (2) NSCM-coated nanoparticles for the treatment of neurodegenerative diseases, and (3) systemic delivery of ASO for the treatment of PD. These findings provide insights into the development of biomimetic BBB penetrable drug carriers for precise diagnosis and therapy of central nervous system diseases.

ROS-responsive Galactosylated-nanoparticles with Doxorubicin Entrapment for Triple Negative Breast Cancer Therapy

Background

Triple negative breast cancer (TNBC) is one of the most aggressive tumors with high metastasis and mortality, which constitutes 15~20% of all breast cancers. Chemotherapy remains main therapeutic option in the treatment of patients with TNBC.

Methods

We developed reactive oxygen species (ROS)-responsive galactosylated nanoparticles (DOX@NPs) as an efficiently targeted carrier for doxorubicin (DOX) delivery to inhibit the growth of TNBC in vitro and in vivo. DOX@NPs were composed of polyacrylate galactose and phenylboronic derivatives conjugation. The in vitro cytotoxicity, cellular uptake, cell apoptosis and cycle distribution of tumor cells treated with different formulations were investigated. Meanwhile in vivo biodistribution and antitumor effects were investigated in a 4T1 tumor-bearing mouse model.

Results

DOX@NPs showed good ROS responsiveness and rapid DOX release in the presence of H₂O₂. Furthermore, our data suggested that DOX@NPs could effectively trigger tumor cells apoptosis and cycle arrest, efficiently accumulate into tumor sites, and suppress tumor growth without adverse side effects.

Conclusion

Our results suggested DOX@NP with potent potential as a promising nanocarrier for TNBC therapy, which deserved further investigation for other cancer treatment.

Constructions of ROS-responsive titanium-hydroxyapatite implant for mesenchymal stem cell recruitment in peri-implant space and bone formation in osteoporosis microenvironment

To solve the issue of unsatisfactory recruitment of mesenchymal stem cells (MSCs) around implant in osteoporotic fractures, we fabricated a ROS-responsive system on titanium surface through hydroxyapatite coating and biomolecule grafting. The porous hydroxyapatite and phosphorylated osteogenic growth peptides (p-OGP) were introduced onto titanium surface to synergistically improve osteogenic differentiation of MSCs. After the p-OGP-promoted expression of osteogenic related proteins, the calcium and phosphate ions were released through the degradation of hydroxyapatite and integrated into bone tissues to boost the mineralization of bone matrix. The ROS-triggered release of DNA aptamer (Apt) 19S in the osteoporotic microenvironment guides MSC migration to implant site due to its high affinity with alkaline phosphatase on the membrane of MSCs. Once MSCs reached the implant interface, their osteogenic differentiation potential was enhanced by p-OGP and hydroxyapatite to promote bone regeneration. The study here provided a simple and novel strategy to prepare functional titanium implants for osteoporotic bone fracture repair.

M, Zarrintaj P, Formela K, Saeb MR, Bencherif SA. Clickable Polysaccharides for Biomedical Applications: A Comprehensive Review

Recent advances in materials science and engineering highlight the importance of designing sophisticated biomaterials with well-defined architectures and tunable properties for emerging biomedical applications. Click chemistry, a powerful method allowing specific and controllable bioorthogonal reactions, has revolutionized our ability to make complex molecular structures with a high level of specificity, selectivity, and yield under mild conditions. These features combined with minimal byproduct formation have enabled the design of a wide range of macromolecular architectures from quick and versatile click reactions. Furthermore, copper-free click chemistry has resulted in a change of paradigm, allowing researchers to perform highly selective chemical reactions in biological environments to further understand the structure and function of cells. In living systems, introducing clickable groups into biomolecules such as polysaccharides (PSA) has been explored as a general approach to conduct medicinal chemistry and potentially help solve healthcare needs. De novo biosynthetic pathways for chemical synthesis have also been exploited and optimized to perform PSA-based bioconjugation inside living cells without interfering with their native processes or functions. This strategy obviates the need for laborious and costly chemical reactions which normally require extensive and time-consuming purification steps. Using these approaches, various PSA-based macromolecules have been manufactured as building blocks for the design of novel biomaterials. Clickable PSA provides a powerful and versatile toolbox for biomaterials scientists and will increasingly play a crucial role in the biomedical field. Specifically, bioclick reactions with PSA have been leveraged for the design of advanced drug delivery systems and minimally invasive injectable hydrogels. In this review article, we have outlined the key aspects and breadth of PSA-derived bioclick reactions as a powerful and versatile toolbox to design advanced polymeric biomaterials for biomedical applications such as molecular imaging, drug delivery, and tissue engineering. Additionally, we have also discussed the past achievements, present developments, and recent trends of clickable PSA-based biomaterials such as 3D printing, as well as their challenges, clinical translatability, and future perspectives.

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.

Hierarchical dual-responsive cleavable nanosystem for synergetic photodynamic/photothermal therapy against melanoma

Currently, the combining photodynamic therapy (PDT) with photothermal therapy (PTT) modalities based on a single near infrared (NIR) laser irradiation and highly selective internalization still remain a challenge. Herein, a hierarchical dual-responsive cleavable nanosystem for synergetic NIR triggered PDT/PTT is reported. The engineered nanoplatform (Au NRs/Cur/UCNPs@PBE) is designed by loading curcumin (Cur, photosensitizer) on gold nanarods (Au NRs) to build PDT/PTT therapy system, which was encapsulated outside with upconversion nanoparticles (UCNPs) and then modified with phenylboronic double ester (PBE). The pH and ROS-responsive feature made Au NRs/Cur/UCNPs@PBE provide a fundamental structural evolution and improve the specificity and intracellular accumulation to tumors. Au NRs/Cur/UCNPs@PBE exhibited significant PDT and PTT efficiency against two type melanoma cells due to upconversion nanoparticles and Au NRs induced by an 808 nm laser. Notably, the platform can mainly activate apoptosis and partial ferroptosis to achieve the synergistic PDT/PTT, furthermore, the integrated PDT with PTT using Au NRs/Cur/UCNPs@PBE showcased a great antitumor efficacy in vivo superior to the other alone treatment. Our findings highlight that this intelligent nanoagents for synergistic phototherapy facilitate enhanced fighting melanoma and provide a promising strategy for melanoma theranostics.

Silica-Based Nanoframeworks Involved Hepatocellular Carcinoma Theranostic

Silica-based nanoframeworks have been extensively studied for diagnosing and treating hepatocellular carcinoma (HCC). Several reviews have summarized the advantages and disadvantages of these nanoframeworks and their use as drug-delivery carriers. Encouragingly, these nanoframeworks, especially those with metal elements or small molecular drugs doping into the skeleton structure or modifying onto the surface of nanoparticles, could be multifunctional components participating in HCC diagnosis and treatment rather than functioning only as drug-delivery carriers. Therefore, in this work, we described the research progress of silica-based nanoframeworks involved in HCC diagnosis (plasma biomarker detection, magnetic resonance imaging, positron emission tomography, photoacoustic imaging, fluorescent imaging, ultrasonography, etc.) and treatment (chemotherapy, ferroptotic therapy, radiotherapy, phototherapy, sonodynamic therapy, immunotherapy, etc.) to clarify their roles in HCC theranostics. Further, the future expectations and challenges associated with silica-based nanoframeworks were highlighted. We believe that this review will provide a comprehensive understanding for researchers to design novel, functional silica-based nanoframeworks that can effectively overcome HCC.

Enantioselective effect of cysteine functionalized mesoporous silica nanoparticles in U87 MG and GM08680 human cells and Staphylococcus aureus bacteria

Chirality is a fundamental phenomenon in biological systems, since most of the biomolecules and biological components and species are chiral and therefore recognize and respond differently depending on the enantiomer present. With increasing research into the use of nanomaterials for biomedical purposes, it is essential to understand the role that chirality of nanoparticles plays at the cellular level. Here, the chiral cysteine functionalization of mesoporous silica nanoparticles has been shown to broadly affect its interaction with U87 MG human glioblastoma cell, healthy human fibroblast (GM08680) and methicillin-resistant S. aureus bacteria. We believe that this research is important to further advancement of nano-biotechnology.

Delivery nanoplatforms based on dynamic covalent chemistry

As a paramount factor to restrict the potential action of drugs and biologics, nanoplatforms based on dynamic covalent chemistry have been demonstrated as promising candidates to fulfill the full requirements during the whole delivery process by the virtue of their remarkable features such as adaptiveness, stimuli-responsiveness, specificity, reversibility and feasibility. This contribution summarizes the latest progress in dynamic covalent bond-based nanoplatforms with improved delivery efficiency and therapeutic performance. In addition, major challenges and perspectives in this field are also discussed. We expect that this feature article will provide a valuable and systematic reference for the further development of dynamic covalent bond-based nanoplatforms.

Bioresponsive nanomedicines based on dynamic covalent bonds

Trends in the development of modern medicine necessitate the efficient delivery of therapeutics to achieve the desired treatment outcomes through precise spatiotemporal accumulation of therapeutics at the disease site. Bioresponsive nanomedicine is a promising platform for this purpose. Dynamic covalent bonds (DCBs) have attracted much attention in studies of the fabrication of bioresponsive nanomedicines with an abundance of combinations of therapeutic modules and carrier function units. DCB-based nanomedicines could be designed to maintain biological friendly synthesis and site-specific release for optimal therapeutic effects, allowing the complex to retain an integrated structure before accumulating at the disease site, but disassembling into individual active components without compromising function in the targeted organs or tissues. In this review, we focus on responsive nanomedicines containing dynamic chemical bonds that can be cleaved by various specific stimuli, enabling achievement of targeted drug release for optimal therapy in various diseases.

Autophagy Modulation and Synergistic Therapy to Combat Multidrug Resistance Breast Cancer Using Hybrid Cell Membrane Nanoparticles

The development of multidrug resistance (MDR) is a commonly observed phenomenon in many cancer types. It contributed significantly to the poor outcome of many currently available chemotherapies. Considering autophagy as one of the most important physiological process in cancer progression, we thereby proposed an anti-autophagy siRNA and doxorubicin (Dox) co-delivery system (MC/D-siR) to combat MDR breast cancer using sequential construction. Our results demonstrated the potential of MC/D-siR to effectively transfect the loaded siRNA to result in significant downregulation of intracellular autophagy level in MCF-7/Adr (Dox resistance MCF-7 cell line) cells, which in turn cut off the ATP supply and to reverse the MDR and potentiated accumulated drug retention in cells. As a result, MC/D-siR showed much elevated anticancer benefits than single loaded platforms (MC/Dox or MC/siRNA), indicating the ability for effective MDR cancer treatment through the combination of autophagy regulation and chemotherapy.

Redox-responsive amphiphilic camptothecin prodrug nanoparticles for targeted liver tumor therapy

Tumor cell-targeting drug delivery systems are of great importance to anti-tumor therapy in clinics. Owing to the overexpression of the asialoglycoprotein receptor (ASGPR) on the membrane of hepatoma carcinoma cells, the conjugation of lactose on the surface of drug delivery systems has already shown significant advantages for targeting tumor cells. In this study, a disulfide bond-conjugated prodrug targeting delivery system consisting of camptothecin (CPT) and lactose (LA) was synthesized, which was denoted as CPT-S-S-LA. Camptothecin and lactose act as the chemotherapy drug and targeting ligand in the drug delivery system, respectively. Since CPT-S-S-LA is an amphiphilic compound, it can self-assemble into nanoparticles with a diameter of around 110 nm. The CPT-S-S-LA nanoparticles displayed controllable drug release behavior in the physiological environment. Unlike the free CPT, the CPT-S-S-LA nanoparticles firstly assembled at the tumor sites via the enhanced permeability and retention (EPR) effect, and then were phagocytized by the tumor cells with ASGP receptor-mediated endocytosis. Finally, the antitumor agent CPT was released for killing tumor cells, which have a high glutathione (GSH) concentration environment. The nanoparticles displayed favorable ability to target hepatoma carcinoma cells rather than the normal HUVEC cells in vitro. Both the in vitro and in vivo studies demonstrated that the CPT-S-S-LA nanoparticles display enhanced antitumor ability and reduced side effects. Thus, active targeting prodrug delivery systems should be a promising strategy for liver tumor therapy.

A nanoplatform based on mesoporous silica-coated gold nanorods for cancer triplex therapy

To enhance the efficacy of nanoparticle-based cancer therapy with reduced side effects and promote its clinical translation, a biocompatible nanocomposite based on mesoporous silica-coated gold nanorods (AuNR@MSN) for triple tumor therapy is reported in this study. The gold core served as a hyperthermia agent, while the MSN shell acted as a reservoir of chemotherapeutics owing to its excellent loading capacity. Cytochrome c with the apoptosis inducing function was anchored on the surface of AuNR@MSN to prevent drug leakage through redox-responsive disulfide bonds. The successful construction of a nanocomposite was confirmed by characterization of the physicochemical properties. In vitro and in vivo studies demonstrated that the nanocomposite displayed an optimizing anti-tumor effect with a synergistic strategy of excellent photothermal therapy, chemotherapy and protein therapy. Therefore, this cooperative strategy paves the way for high-efficiency oncotherapy with reduced side effects.

Co-delivery of cisplatin and oleanolic acid by silica nanoparticles-enhanced apoptosis and reverse multidrug resistance in lung cancer

Multidrug resistance (MDR) of chemotherapy is one of the significant concerns in cancer therapy. Here in our study, cisplatin (DDP) and oleanolic acid (OA) were co-loaded in mesoporous silica nanoparticles (Nsi) to construct DDP/OA-Nsi and solve the DDP-resistance in lung cancer therapy. The cytotoxicity and apoptosis assays demonstrated that in DDP-resistant A549/DDP cells, the cytotoxicity of DDP/OA-Nsi was significantly higher than that of free DDP or DDP single delivery system (DDP-Nsi). The intracellular drug accumulation study revealed that the intracellular DDP concentration in the DDP/OA-Nsi group was also higher than that in free DDP and DDP-Nsi groups. In the A549/DDP xenograft tumor model, DDP/OA-Nsi showed the best anticancer effect. In summary, DDP/OA-Nsi was a promising drug delivery system to solve MDR in lung cancer therapy.

SQ3370 Activates Cytotoxic Drug via Click Chemistry at Tumor and Elicits Sustained Responses in Injected & Non-injected Lesions

While systemic immuno-oncology therapies have shown remarkable success, only a limited subset of patients benefit from them. Our Click Activated Protodrugs Against Cancer (CAPAC™) Platform is a click chemistry-based approach that activates cancer drugs at a specific tumor with minimal systemic toxicity. CAPAC Platform is agnostic to tumor characteristics that can vary across patients and hence applicable to several types of tumors. We describe the benefits of SQ3370 (lead candidate of CAPAC) to achieve systemic anti-tumor responses in mice bearing two tumors. SQ3370 consists of a biopolymer, injected in a single lesion, followed by systemic doses of an attenuated protodrug™ of doxorubicin (Dox). SQ3370 was well-tolerated at 5.9-times the maximum dose of conventional Dox, increased survival by 63% and induced a systemic anti-tumor response against injected and non-injected lesions. The sustained anti-tumor response also correlated with immune activation measured at both lesions. SQ3370 could potentially benefit patients with micro-metastatic lesions.

Therapeutic Nanoparticles and Their Targeted Delivery Applications

Nanotechnology offers many advantages in various fields of science. In this regard, nanoparticles are the essential building blocks of nanotechnology. Recent advances in nanotechnology have proven that nanoparticles acquire a great potential in medical applications. Formation of stable interactions with ligands, variability in size and shape, high carrier capacity, and convenience of binding of both hydrophilic and hydrophobic substances make nanoparticles favorable platforms for the target-specific and controlled delivery of micro- and macromolecules in disease therapy. Nanoparticles combined with the therapeutic agents overcome problems associated with conventional therapy; however, some issues like side effects and toxicity are still debated and should be well concerned before their utilization in biological systems. It is therefore important to understand the specific properties of therapeutic nanoparticles and their delivery strategies. Here, we provide an overview on the unique features of nanoparticles in the biological systems. We emphasize on the type of clinically used nanoparticles and their specificity for therapeutic applications, as well as on their current delivery strategies for specific diseases such as cancer, infectious, autoimmune, cardiovascular, neurodegenerative, ocular, and pulmonary diseases. Understanding of the characteristics of nanoparticles and their interactions with the biological environment will enable us to establish novel strategies for the treatment, prevention, and diagnosis in many diseases, particularly untreatable ones.

Emerging and Innovative Theranostic Approaches for Mesoporous Silica Nanoparticles in Hepatocellular Carcinoma: Current Status and Advances

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal solid cancers globally. To improve diagnosis sensitivities and treatment efficacies, the development of new theranostic nanoplatforms for efficient HCC management is urgently needed. In the past decade, mesoporous silica nanoparticles (MSNs) with tailored structure, large surface area, high agents loading volume, abundant chemistry functionality, acceptable biocompatibility have received more and more attention in HCC theranostic. This review outlines the recent advances in MSNs-based systems for HCC therapy and diagnosis. The multifunctional hybrid nanostructures that have both of therapy and diagnosis abilities are highlighted. And the precision delivery strategies of MSNs in HCC are also discussed. Final, we conclude with our personal perspectives on the future development and challenges of MSNs.

Hydrolytic surface erosion of mesoporous silica nanoparticles for efficient intracellular delivery of cytochrome c

Delivery of apoptosis-associated proteins is an attractive approach to treat cancer, but their large molecular sizes and membrane-impermeability require the use of a suitable delivery carrier. As a versatile drug carrier, mesoporous silica nanoparticles (MSNs) have been utilized to transport a variety of therapeutic molecules. However, the use of MSNs for protein delivery has been limited because their conventionally obtainable pore size (ca. 2-3 nm in diameter) is too small to load large-sized biomolecular cargos. In this article, we present surface erosion of MSNs by hydrolytic degradation as a new strategy to obtain a mesoporous colloidal carrier for effective delivery of a bulky apoptosis-inducible protein, cytochrome c (CYT). A series of physicochemical properties of particles were analyzed before and after the hydrolytic surface erosion of pristine small-pored MSNs and the subsequent CYT loading. The results showed that hydrolytic degradation of MSNs imparts beneficial structural features for CYT loading and release, i.e., enlarged pores (up to ~10 nm in diameter) and roughened surface texture, leading to significantly enhanced intracellular delivery of CYT over conventional small-pored MSNs. The present results may offer a useful insight into silica degradability for tuning the internal/external surface characteristics of MSN-based colloidal particles to open a wide range of biomedical applications.

Recent Advances on Reactive Oxygen Species-Responsive Delivery and Diagnosis System

Reactive oxygen species (ROS) play crucial roles in biological metabolism and intercellular signaling. However, ROS level is dramatically elevated due to abnormal metabolism during multiple pathologies, including neurodegenerative diseases, diabetes, cancer, and premature aging. By taking advantage of the discrepancy of ROS levels between normal and diseased tissues, a variety of ROS-sensitive moieties or linkers have been developed to design ROS-responsive systems for the site-specific delivery of drugs and genes. In this review, we summarized the ROS-responsive chemical structures, mechanisms, and delivery systems, focusing on their current advances for precise drug/gene delivery. In particular, ROS-responsive nanocarriers, prodrugs, and supramolecular hydrogels are summarized in terms of their application for drug/gene delivery, and common strategies to elevate or diminish cellular ROS concentrations, as well as the recent development of ROS-related imaging probes were also discussed.

Self-Strengthened Oxidation-Responsive Bioactivating Prodrug Nanosystem with Sequential and Synergistically Facilitated Drug Release for Treatment of Breast Cancer

Although environment-sensitive prodrug-based nanoparticles (NPs) have developed rapidly, lots of prodrug NPs still show poor selectivity and efficiency of parent drug bioactivation because of tumor heterogeneity. Herein, self-strengthened bioactivating prodrug-based NPs are fabricated via co-encapsulation of oxidation-responsive thioether-linked linoleic acid-paclitaxel conjugates (PTX-S-LA) and β-lapachone (LPC) into polymeric micelles (PMs). Following cellular uptake, PMs first release LPC to significantly elevate the reactive oxidative species (ROS) level through NAD(P)H: quinone oxidoreductase-1 (NQO1) catalysis. Then, NQO1-generated ROS in combination with endogenous high ROS levels in tumor cells could synergistically facilitate PTX-S-LA to release the active cytotoxic agent PTX. Such a novel prodrug nanosystem exhibits self-strengthened prodrug bioactivation, ultraselective release, and cytotoxicity between cancer and normal cells, prolonged circulation time, and enhanced tumor accumulation, leading to high antitumor efficiency and superior biosafety. Our findings pave the new way for the rational design of oxidation-responsive prodrug NPs for high-efficacy cancer chemotherapy.

Cascade-amplification of therapeutic efficacy: An emerging opportunity in cancer treatment

Increasing research evidence reveals that cancer is complex disease involving many biological factors, processes and systems, which may severely limit the actual efficacy of conventional monotonic anticancer approaches. To overcome these obstacles in cancer treatment, a new strategy has been proposed by combining multiple synergistic therapeutic modalities accessing different but inherently related targets and acting sequentially. A major benefit of this strategy is that the multi-target mechanism could result in a cascade-amplification effect leading to enhanced anticancer activity. In this review, we provide a critical discussion on the application of cascade-amplification strategy in the treatment of various cancer indications, focusing on the rational combination of therapeutic agents and their mechanisms of action. A concise yet comprehensive analysis on the potential therapeutic benefit of this strategy was also included. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Advances in mesoporous silica nanoparticles for targeted stimuli-responsive drug delivery: an update

INTRODUCTION

Mesoporous silica nanoparticles (MSNs) are outstanding nanoplatforms for drug delivery. Herein, the most recent advances to turn MSN-based carriers into minimal side effect drug delivery agents are covered.

AREAS COVERED

This review summarizes the scientific advances dealing with MSNs for targeted and stimuli-responsive drug delivery since 2015. Delivery aspects to diseased tissues together with approaches to obtain smart MSNs able to respond to internal or external stimuli and their applications are here described. Special emphasis is done on the combination of two or more stimuli on the same nanoplatform and on combined drug therapy.

EXPERT OPINION

The use of MSNs in nanomedicine is a promising research field because they are outstanding platforms for treating different pathologies. This is possible thanks to their structural, chemical, physical and biological properties. However, there are certain issues that should be overcome to improve the suitability of MSNs for clinical applications. All materials must be properly characterized prior to their in vivo evaluation; furthermore, preclinical in vivo studies need to be standardized to demonstrate the MSNs clinical translation potential.

Regulation of osteoblast differentiation by osteocytes cultured on sclerostin antibody conjugated TiO2 nanotube array

Sclerostin is a negative regulator of the Wnt signaling pathway for osteoblast differentiation. In this study, osteoblasts were co-cultured with osteocytes (MLO-Y₄ cells) on the surface of sclerostin antibody-conjugated TiO₂ nanotube arrays (TNTs-scl). Field emission scanning electron microscopy (SEM), contact angle measurement and confocal laser scanning microscope (CLSM) were employed to characterize the conjugation of sclerostin antibody onto the surface of TiO₂ nanotube arrays. The cellular viability and morphology results displayed TNTs-scl (TNT30-scl and TNT70-scl) were beneficial to the growth of MLO-Y4 cells. There was no apparent change in sclerostin gene expression between MLO-Y4 cells grown on TNTs and TNTs-scl. However, TNTs-scl significantly reduced the amount of sclerostin in the medium. In comparison with the control groups, osteoblasts displayed higher differentiation capability when co-cultured with MLO-Y4 cells on the surface TNTs-scl, which was indicated by the ALP activity, mineralization capability as well as expression levels of key proteins in Wnt signaling. This study provides a simple strategy to engineer titanium surface for bone fracture recovery, especially in osteoporotic conditions.