Multifunctional Hypoxia-Involved Gene Silencing Nanoplatform for Sensitizing Photochemotherapy

Drug carrier wonders: Synthetic strategies of zeolitic imidazolates frameworks (ZIFs) and their applications in drug delivery and anti-cancer activity

With the rapid advancement of nanotechnology, stimuli-responsive nanomaterials have emerged as a feasible choice for the designing of controlled drug delivery systems. Zeolitic imidazolates frameworks are a subclass of Metal-organic frameworks (MOFs) that are recognized by their excellent porosity, structural tunability and chemical modifications make them promising materials for loading targeted molecules and therapeutics agents. The biomedical industry uses these porous materials extensively as nano-carriers in drug delivery systems. These MOFs not only possess excellent targeted imaging ability but also cause the death of tumor cells drawing considerable attention in the current framework of anticancer drug delivery systems. In this review, the outline of stability, porosity, mechanism of encapsulation and release of anticancer drug have been reported extensively. In the end, we also discuss a brief outline of current challenges and future perspectives of ZIFs in the biomedical world.

Recent advances in functional nucleic acid decorated nanomaterials for cancer imaging and therapy

Nanomaterials possess unusual physicochemical properties including unique optical, magnetic, electronic properties, and large surface-to-volume ratio. However, nanomaterials face some challenges when they were applied in the field of biomedicine. For example, some nanomaterials suffer from the limitations such as poor selectivity and biocompatibility, low stability, and solubility. To address the above-mentioned obstacles, functional nucleic acid has been widely served as a powerful and versatile ligand for modifying nanomaterials because of their unique characteristics, such as ease of modification, excellent biocompatibility, high stability, predictable intermolecular interaction and recognition ability. The functionally integrating functional nucleic acid with nanomaterials has produced various kinds of nanocomposites and recent advances in applications of functional nucleic acid decorated nanomaterials for cancer imaging and therapy were summarized in this review. Further, we offer an insight into the future challenges and perspectives of functional nucleic acid decorated nanomaterials.

Acriflavine, an Acridine Derivative for Biomedical Application: Current State of the Art

Acriflavine (ACF) has been known for years as an antibacterial drug. The identification of key oncogenic mechanisms has brought, in recent years, a significant increase in studies on ACF as a multipurpose drug that would improve the prognosis for cancer patients. ACF interferes with the expression of the hypoxia inducible factor, thus acting on metastatic niches of tumors and significantly enhancing the effects of other anticancer therapies. It has been recognized as the most potent HIF-1 inhibitor out of the 336 drugs approved by the FDA. This work presents up-to-date knowledge about the mechanisms of action of ACF and its related prodrug systems in the context of anticancer and SARS-CoV-2 inhibitory properties. It explains the multitask nature of this drug and suggests mechanisms of ACF’s action on the coronavirus. Other recent reports on ACF-based systems as potential antibacterial and antiviral drugs are also described.

Nanoscale Zeolitic Imidazolate Framework (ZIF)–8 in Cancer Theranostics: Current Challenges and Prospects

Simple Summary

The biomedical application of metal–organic frameworks in cancer theranostics has become a research hotspot with rapid progress. As a typical representative, ZIF–8 attracts increasing interest from researchers due to its good performance and potential. In this review, we updated recent discoveries on the ZIF–8–based nanoplatforms for cancer, discussed the problems in current research and the obstacles for clinical translation of ZIF–8, and also proposed an outlook on its future development.

Abstract

Cancer severely threatens human health and has remained the leading cause of disease–related death for decades. With the rapid advancement of nanomedicine, nanoscale metal–organic frameworks are believed to be potentially applied in the treatment and biomedical imaging for various tumors. Zeolite imidazole framework (ZIF)–8 attracts increasing attention due to its high porosity, large specific surface area, and pH–responsiveness. The designs and modifications of ZIF–8 nanoparticles, as well as the strategy of drug loading, demand a multifaceted and comprehensive understanding of nanomaterial features and tumor characteristics. We searched for studies on ZIF–8–based nanoplatforms in tumor theranostics on Web of Science from 2015 to 2022, mainly focused on the research published in the past 3 years, summarized the progress of their applications in tumor imaging and treatment, and discussed the favorable aspects of ZIF–8 nanoparticles for tumor theranostics as well as the future opportunities and potential challenges. As a kind of metal–organic framework material full of potential, ZIF–8 can be expected to be combined with more therapeutic systems in the future and continue to contribute to all aspects of tumor therapy and diagnosis.

Nanodelivery Systems Delivering Hypoxia-Inducible Factor-1 Alpha Short Interfering RNA and Antisense Oligonucleotide for Cancer Treatment

Hypoxia-inducible factor (HIF), which plays a crucial role in oxygen homeostasis, contributes to immunosuppression, tumor angiogenesis, multidrug resistance, photodynamic therapy resistance, and metastasis. HIF as a therapeutic target has attracted scientists’ strong academic research interests. Short interfering RNA (siRNA) and antisense oligonucleotide (ASO) are the more promising and broadly utilized methods for oligonucleotide-based therapy. Their physicochemical characteristics such as hydrophilicity, negative charge, and high molecular weight make them impossible to cross the cell membrane. Moreover, siRNA and ASO are subjected to a rapid deterioration in circulation and cannot translocate into nuclear. Delivery of siRNA and ASO to specific gene targets should be realized without off-target gene silencing and affecting the healthy cells. Nanoparticles as vectors for delivery of siRNA and ASO possess great advantages and flourish in academic research. In this review, we summarized and analyzed regulation mechanisms of HIF under hypoxia, the significant role of HIF in promoting tumor progression, and recent academic research on nanoparticle-based delivery of HIF siRNA and ASO for cancer immunotherapy, antiangiogenesis, reversal of multidrug resistance and radioresistance, potentiating photodynamic therapy, inhibiting tumor metastasis and proliferation, and enhancing apoptosis are reviewed in this thesis. Furthermore, we hope to provide some rewarding suggestions and enlightenments for targeting HIF gene therapy.

Adenosine triphosphate/pH dual-responsive controlled drug release system with high cancer/normal cell selectivity and low side toxicity

Most drug-delivery systems (DDS) suffer from poor selectivity to cancer/normal cells or the complicated synthetic process. Herein, we employed a novel facile method to develop an oligodeoxy nucleotides based DDS composed with adenosine-5′- triphosphate (ATP) aptamer and a pH responsive cytosine (C) DNA fragment for specific daunomycine (DNM) delivery. The DDS has ATP/pH dual-responsive drug release, can selectively internalize into tumor cell lines and thus has ultrahigh cancer/normal cell selectivity over the individual drug. The non-chemical synthesis, controllable dual-responsive intracellular drug release, and high cancer/normal cell selectivity endowed the DDS high biocompatibility and significant tumor suppression.

Engineering nanomedicines to inhibit hypoxia-inducible Factor-1 for cancer therapy

Hypoxia-inducible factor-1 (HIF-1), an essential promoter of tumor progression, has attracted increasing attention as a therapeutic target. In addition to hypoxic cellular conditions, HIF-1 activation can be triggered by cancer treatment, which causes drug tolerance and therapeutic failure. To date, a series of effective strategies have been explored to suppress HIF-1 function, including silencing the HIF-1α gene, inhibiting HIF-1α protein translation, degrading HIF-1α protein, and inhibiting HIF-1 transcription. Furthermore, nanoparticle-based drug delivery systems have been widely developed to improve the stability and pharmacokinetics of HIF-1 inhibitors or achieve HIF-1-targeted combination therapies as a nanoplatform. In this review, we summarize the current literature on nanomedicines targeting HIF-1 to combat cancer and discuss their potential for future development.

Intelligent Tumor Microenvironment-Activated Multifunctional Nanoplatform Coupled with Turn-on and Always-on Fluorescence Probes for Imaging-Guided Cancer Treatment

Intrinsic tumor microenvironment (TME)-related therapeutic resistance and nontumor-specific imaging have limited the application of imaging-guided cancer therapy. Herein, a TME-responsive MnO₂-based nanoplatform coupled with turn-on and always-on fluorescence probes was designed through a facile biomineralization method for imaging-guided photodynamic/chemodynamic/photothermal therapy (PDT/CDT/PTT). After the tumor-targeting delivery of the AuNCs@MnO₂-ICG@AS1411 (AMIT) nanoplatform via aptamer AS1411, the TME-responsive dissociation of MnO₂ generated sufficient O₂ and Mn²⁺ with the consumption of GSH for improving PDT efficacy and Fenton-like reaction-mediated CDT. Simultaneously, the released small-sized ICG and AuNCs facilitated PDT and PTT efficacy via the deep tumor penetration. Moreover, the turn-on fluorescence of AuNCs revealed the real-time TME-responsive MnO₂ degradation process, and the always-on ICG fluorescence enabled the in situ monitoring of the payload distribution in vitro and in vivo. The AMIT NPs also provided magnetic resonance and thermal imaging guidance for the enhanced PDT, CDT, and PTT. Therefore, this all-in-one nanosystem provides a simple and versatile strategy for multiple imaging-guided theranostic applications.

Metal-Organic Framework Nanoparticles Power DNAzyme Logic Circuits for Aberrant MicroRNA Imaging

At the molecular level, a large number of studies exist on the use of dynamic DNA molecular circuits for disease diagnosis and biomedicine. However, how to design programmable molecular circuit devices to autonomously and accurately diagnose multiple low-abundance biomolecules in complex cellular environments remains a challenge. Here, we constructed DNAzyme logic circuits for the analysis and imaging of multiple microRNAs in living cells using Cu/ZIF-8 NPs as a nanocarrier of the logic gate modules and the Cu²⁺ cofactor of the Cu²⁺-dependent DNAzyme. The logic gate modules of the logic operation system were adsorbed on the surface of Cu/ZIF-8 NPs via electrostatic interaction. After internalization, pH-responsive Cu/ZIF-8 NPs could efficiently release the logic gate modules and Cu²⁺, which allowed us to realize multiple logic computations initiated by endogenous miRNA, including one YES logic gate and two binary logic gates (OR and AND) in different living cells. Cu²⁺-DNAzyme logic circuits could quickly respond to multiple endogenous miRNAs in the complex cell environment, which also provided a new research method for the application of DNA biocomputing circuits in living cells.

An efficient photochemotherapy nanoplatform based on the endogenous biosynthesis of photosensitizer in macrophage-derived extracellular vesicles

Extracellular vesicles (EVs) have been emerged as versatile drug delivery vehicles due to their outstanding biocompatibility and long-term circulation, yet are constrained with low targeting property and inefficient loading capacity from post-synthetic passive EVs encapsulation. Herein, we report a simple and feasible in situ biosynthetic approach to encapsulate tumor-targeting folate (FA)-modified EVs with intracellularly produced protoporphyrin X (PpIX) and doxorubicin (DOX). As compared with the traditional directly drug-incubated or drug-electroporated EVs, these biosynthesized EVs revealed high drug-loading efficiency with minimized structural and functional perturbations. Our multifunctional EVs revealed the enhanced accumulation and penetration into deep tumor parenchyma, as well as the strengthened immune response to ablate orthotopic and metastatic tumors, thus realizing the more reliable photochemotherapy. As an intelligent multi-mode therapeutic system, our biosynthetic EVs could be engineered with more therapeutic agents and show great promise for biomedicine applications.

A multimodal strategy of Fe3O4@ZIF-8/GOx@MnO2 hybrid nanozyme via TME modulation for tumor therapy

Weak acidity (6.5-6.9) and limited H₂O₂ level in the tumor microenvironment (TME) usually impact the therapeutic effect of chemodynamic therapy (CDT) for cancer. A Specific TME promotes the formation of an immunosuppressive microenvironment and results in high rate of recurrence and metastasis of cancer. Fe₃O₄@ZIF-8/GOx@MnO₂ multi-layer core shell nanostructure was constructed as a hybrid nanozyme. After magnetic targeting of the tumor site, the outermost MnO₂ shell catalyzed H₂O₂ in TME to produce O₂ and was broken due to the reaction with glutathione. Due to the acid response, the ZIF-8 layer would crack and release glucose oxidase (GOx) and Fe₃O₄. The generated O₂ was utilized by GOx in starvation therapy to consume glucose and produce H₂O₂ and gluconic acid. The Fenton reaction efficiency of Fe(II) was improved by the increased H₂O₂ concentration and the enhanced acidity in TME. At the same time, the intrinsic photothermal effect of Fe₃O₄ upon 808 nm laser irradiation promoted the activity of MnO₂ and GOx as oxidase, and Fe(II) as catalase-like, and ablated the primary tumor. Moreover, the hybrid nanozyme can facilitate the transformation of M2-type macrophages to M1-type, and strong systemic antitumor immune effect was induced. A synergy of multiple therapeutic modes including starvation therapy, CDT, photothermal therapy (PTT), and immunotherapy can be realized in the hybrid nanozyme for tumor therapy.

Emerging nanotechnological strategies to reshape tumor microenvironment for enhanced therapeutic outcomes of cancer immunotherapy

Immunotherapy was emerged as a novel cancer treatment in the last decade, however, efficacious responses to mono-immunotherapy have only been achieved in a relatively small portion of patients whereas combinational immunotherapies often lead to concurrent side effects. It has been proved that the tumor microenvironment (TME) is responsible for tumor immune escape and the ultimate treatment failure. Recently, both the understanding of the TME and the applications of nanotechnological strategies have achieved remarkable progresses, and reviewing the emerging immune-regulatory nanosystems may provide valuable information for specifically modulating the TME at different immune stages. In this review, we focus on comprehending the recently proposed T-cell-based tumor classification and identifying the most promising targets for different tumor phenotypes, and then summarizing the nanotechnological strategies to best target corresponding immune-related factors. For future precise personalized immunotherapy, the tailor-made TME modulation strategies conducted by well-designed nanosystems to alleviate the suppressive TME and then promote anti-tumor immune responses will significantly benefit the clinical outcomes of cancer patients.