Doxorubicin-Loaded Metal-Organic Framework Nanoparticles as Acid-Activatable Hydroxyl Radical Nanogenerators for Enhanced Chemo/Chemodynamic Synergistic Therapy

Biomedical application of metal-organic frameworks (MOFs) in cancer therapy: Stimuli-responsive and biomimetic nanocomposites in targeted delivery, phototherapy and diagnosis

The nanotechnology is an interdisciplinary field that has become a hot topic in cancer therapy. Metal-organic frameworks (MOFs) are porous materials and hybrid composites consisted of organic linkers and metal cations. Despite the wide application of MOFs in other fields, the potential of MOFs for purpose of cancer therapy has been revealed by the recent studies. High surface area and porosity, significant drug loading and encapsulation efficiency are among the benefits of using MOFs in drug delivery. MOFs can deliver genes/drugs with selective targeting of tumor cells that can be achieved through functionalization with ligands. The photosensitizers and photo-responsive nanostructures including carbon dots and gold nanoparticles can be loaded in/on MOFs to cause phototherapy-mediated tumor ablation. The immunogenic cell death induction and increased infiltration of cytotoxic CD8+ and CD4+ T cells can be accelerated by MOF platforms in providing immunotherapy of tumor cells. The stimuli-responsive MOF platforms responsive to pH, redox, enzyme and ion can accelerate release of therapeutics in tumor site. Moreover, MOF nanocomposites can be modified ligands and green polymers to improve their selectivity and biocompatibility for cancer therapy. The application of MOFs for the detection of cancer-related biomarkers can participate in the early diagnosis of patients.

LncRNA SLC7A11-AS1 stabilizes CTCF by inhibiting its UBE3A-mediated ubiquitination to promote melanoma metastasis

Malignant melanoma (MM) is one of the most aggressive types of skin cancer. Long non-coding RNAs (lncRNAs) are important regulatory factors in the pathogenesis of various diseases. Here, we found that the lncRNA SLC7A11-AS1 was highly expressed in MM. Therefore, we investigated its regulatory role in the migration and invasion of MM cells and the associated mechanism. SLC7A11-AS1 and CTCF levels in MM cell lines were detected using RT-qPCR and western blotting, and their regulatory effects on the migratory and invasive abilities were determined using CCK-8, EdU, transwell, wound-healing assays and mouse model. RNA pull-down and RIP assays were performed to explore the association of SLC7A11-AS1 and CTCF and the correlation between CTCF and UBE3A. SLC7A11-AS1 and CTCF were highly expressed in MM cells. The knockdown of SLC7A11-AS1 decreased the expression of CTCF. Mechanistically, SLC7A11-AS1 inhibited the degradation of CTCF by inhibiting the ubiquitination by UBE3A. The knockdown of both SLC7A11-AS1 and CTCF inhibited the migration and invasion of MM cells and attenuated MM-to-lung metastasis in a mouse model. Taken together, SLC7A11-AS1 promoted the invasive and migratory abilities of MM cells by inhibiting the UBE3A-regulated ubiquitination of CTCF. Therefore, SLC7A11-AS1 may be a potential therapeutic target for MM.

Current status of Fe-based MOFs in biomedical applications

Recently nanoparticle-based platforms have gained interest as drug delivery systems and diagnostic agents, especially in cancer therapy. With their ability to provide preferential accumulation at target sites, nanocarrier-constructed antitumor drugs can improve therapeutic efficiency and bioavailability. In contrast, metal-organic frameworks (MOFs) have received increasing academic interest as an outstanding class of coordination polymers that combine porous structures with high drug loading via temperature modulation and ligand interactions, overcoming the drawbacks of conventional drug carriers. FeIII-based MOFs are one of many with high biocompatibility and good drug loading capacity, as well as unique Fenton reactivity and superparamagnetism, making them highly promising in chemodynamic and photothermal therapy, and magnetic resonance imaging. Given this, this article summarizes the applications of FeIII-based MOFs in three significant fields: chemodynamic therapy, photothermal therapy and MRI, suggesting a logical route to new strategies. This article concludes by summarising the primary challenges and development prospects in these promising research areas.

A pH-responsive bi-MIL-88B MOF coated with folic acid-conjugated chitosan as a promising nanocarrier for targeted drug delivery of 5-Fluorouracil

Cancer has remained one of the leading causes of death worldwide, with a lack of effective treatment. The intrinsic shortcomings of conventional therapeutics regarding tumor specificity and non-specific toxicity prompt us to look for alternative therapeutics to mitigate these limitations. In this regard, we developed multifunctional bimetallic (FeCo) bi-MIL-88B-FC MOFs modified with folic acid-conjugated chitosan (FC) as drug delivery systems (DDS) for targeted delivery of 5-Fluorouracil (5-FU). The bi-MIL-88B nanocarriers were characterized through various techniques, including powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Interestingly, 5-FU@bi-MIL-88B-FC showed slower release of 5-FU due to a gated effect phenomenon endowed by FC surface coating compared to un-modified 5-FU@bi-MIL-88B. The pH-responsive drug release was observed, with 58% of the loaded 5-FU released in cancer cells mimicking pH (5.2) compared to only 24.9% released under physiological pH (5.4). The in vitro cytotoxicity and cellular internalization experiments revealed the superiority of 5-FU@bi-MIL-88B-FC as a highly potent targeted DDS against folate receptor (FR) positive SW480 cancer cells. Moreover, due to the presence of Fe and Co in the structure, bi-MIL-88B exhibited peroxidase-like activity for chemodynamic therapy. Based on the results, 5-FU@bi-MIL-88B-FC could serve as promising candidate for smart DDS by sustained drug release and selective targeting.

Application of Metal-Organic Frameworks for Efficient Removal of Doxorubicin Hydrochloride: Removal Process Optimization and Biological Activity

This study looked at the doxorubicin hydrochloride (DOX) anticancer drug's adsorption characteristics on a silver-based metal-organic framework (Ag-MOF). X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used for the characterization of Ag-MOF. The pore volume and surface area of Ag-MOF were determined through Brunauer-Emmett-Teller (BET) testing at 77 K to be 0.509 cm3/g and 676.059 m2/g, respectively. Adsorption at pH 6 was established to be the best for DOX compared to alkaline solution. Ag-MOF has a good capacity for eliminating DOX (1.85 mmol/g), according to adsorption experiments. From the adsorption results, we can find that Langmuir is the most fitted adsorption isotherm model and the pseudo-second order model best fitted the adsorption kinetics. The energy of activation for adsorption, which was determined to be 15.23 kJ/mol, also supported a chemisorption process. The mechanism of adsorption was evaluated, and details of all possible interactions between DOX and Ag-MOF were illustrated. On the other hand, while examining the impact of temperature, we identified the thermodynamic constraints as ΔG°, ΔH°, and ΔS° and confirmed that the reaction was an endothermic one and spontaneous. Even after numerous reuse cycles, the efficiency remained constant. The synthetic adsorbent was remarkably recyclable at a rate of more than 91.6%. By using the MTT assay, the cytotoxicity of the tested Ag-MOF and DOX@Ag-MOF against human breast cancer cells (MCF-7) was evaluated in vitro. The in vitro antimicrobial activity of Ag-MOF and DOX@Ag-MOF was also tested.

Recent advances in nanoscale metal-organic frameworks for cancer chemodynamic therapy

Chemodynamic therapy (CDT), a novel therapeutic approach based on Fenton (Fenton-like) reaction, has been widely employed for tumor therapy. This approach utilizes Fe, Cu, or other metal ions (Mn, Zn, Co, or Mo) to react with the excess hydrogen peroxide (H₂O₂) in tumor microenvironments (TME), and form highly cytotoxic hydroxyl radical (˙OH) to kill cancer cells. Recently, nanoscale metal-organic frameworks (nMOFs) have attracted considerable attention as promising CDT agents with the rapid development of cancer CDT. This review focuses on summarizing the latest advances (2020-2022) on the design of nMOFs as nanomedicine for CDT or combination therapy of CDT and other therapies. The future development and challenges of CDT are also proposed based on recent progress. Our group hopes that this review will enlighten the research and development of nMOFs for CDT.

Homologous cancer cell membrane-camouflaged nanoparticles target drug delivery and enhance the chemotherapy efficacy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common digestive tract malignancy that seriously threatens human life and health. Early HCC may be treated by intervention, surgery, and internal radiotherapy, while the choice for late HCC is primarily chemotherapy to prolong patient survival. Lenvatinib (LT) is a Food and Drug Administration (FDA)-approved frontline drug for the treatment of advanced liver cancer and has achieved excellent clinical efficacy. However, its poor solubility and severe side effects cannot be ignored. In this study, a bionic nanodrug delivery platform was successfully constructed. The platform consists of a core of Lenvatinib wrapped with a pH-sensitive polymer, namely, poly(β-amino ester)-polyethylene glycol-amine (PAE-PEG-NH₂), and a shell formed by a cancer cell membrane (CCM). The prepared nanodrugs have high drug loading capacity, long-term stability, good biocompatibility, and a long retention time. In addition, the targeting effect of tumor cell membranes and the pH-responsive characteristics of the polymer materials enable them to precisely target tumor cells and achieve responsive release in the tumor microenvironment, which makes them suitable for effective drug delivery. In vivo experiments revealed that the nanodrug showed superior tumor accumulation and therapeutic effects in subcutaneous tumor mice model and could effectively eliminate tumors within 21 days. As a result, it opens up a new way to reduce side effects and improve the specific therapeutic effect of first-line clinical medications to treat tumors.

Self-assembled thioether-bridged paclitaxel-dihydroartemisinin prodrug for amplified antitumor efficacy-based cancer ferroptotic-chemotherapy

Ferroptosis has been proposed as one form of iron-dependent cell death, overgeneration of high-toxicity hydroxyl radicals (˙OH) tumor sites via Fenton reactions induced cell membrane damage. However, the insufficient intracellular concentrations of both iron and H₂O₂ limited the anticancer performance of ferroptosis. In this study, ROS-sensitive prodrug nanoassemblies composed of a PEG2000-ferrous compound and a single thioether bond bridged dihydroartemisinin-paclitaxel prodrug were constructed, which fully tapped ex/endogenous iron, ferroptosis inducers, and chemotherapeutic agents. Following cellular uptake, the intracellular oxidizing environment accelerated the self-destruction of nanoassemblies and triggered drug release. In addition to the chemotherapeutic effect, the activated dihydroartemisinin was capable of acting as a toxic ˙OH amplifier via the reinforced Fenton reaction, simultaneously depleting intracellular GSH, as well as inducing glutathione peroxidase 4 inactivation, further enhancing ferroptosis-dependent cancer cell proliferation inhibition. Meanwhile, the ROS generation-inductive and cell cycle arrest effect from the paclitaxel augmented synergetic ferroptotic-chemotherapy of cancer. Thus, the prodrug integrating dihydroartemisinin with paclitaxel via a single thioether bond represents a potent nanoplatform to exert amplified ferroptotic-chemotherapy for improved anticancer efficacy.

Enhancement of the Solubility of BS Class II Drugs with MOF and MOF/GO Composite Materials: Case Studies of Felodipine, Ketoprofen and Ibuprofen

In this research, a novel composite material composed of Metal-Organic Framework material (MOF) and graphite oxide was synthesized and evaluated as a possible drug-loading vehicle. HKUST-1, a MOF material originally designed by the Hong Kong University of Science and Technology, was used as a model porous material. The aim was to synthesize a drug delivery vehicle for modifying the release kinetics and solubility of poorly soluble drugs (BSC Class II drugs); these are drugs that are known to have poor bioavailability due to their low solubility. We used ketoprofen, ibuprofen, and felodipine as models for BSC Class II drugs. The drugs were loaded onto composite materials through adsorption. The adsorption of these three drugs into the matrix of HKUST-1/GO (graphite oxide), HKUST-1, and graphite oxide was compared. The loading efficiency of the drugs onto the carrier was dependent on the drug molecule and the composition of the drug carrier. The inclusion of graphite oxide in the drug carrier matrix improved the drug loading capacity and modified the drug release rate. The loading of the three drugs felodipine, ketoprofen, and ibuprofen onto HKUST-1 were 33.7, 58, and 79 mg/g respectively. The incorporation of GO into the HKUST-1 matrix resulted in an increase in the loading by 16 and 4 mg/g for the ketoprofen and ibuprofen drugs. When compared to the pure drugs, the solubility of all three drugs in the HKUST-1/GO matrix increased by at least 6 folds.

A copper nanocluster-based multifunctional nanoplatform for augmented chemo/chemodynamic/photodynamic combination therapy of breast cancer

With the development of nano drug delivery system, the treatment mode that can overcome the shortcomings of chemotherapy drugs and integrate combined therapy remains to be explored. Herein, a nano drug system was designed to achieve the combined effect of chemo/chemodynamic/photodynamic therapy on cancer. Specifically, copper clusters (CuNCs) were used as the carrier, hyaluronic acid (HA) and doxorubicin (DOX) were coupled on CuNCs and then and chlorin e6 (Ce6) was introduced to form the self-assembled HA-CuNCs@DC nanoparticles. In this system, the HA-CuNCs@DC was involved in the reaction to the acidic tumor microenvironment (TME)-release of DOX, which could not only inhibit tumor growth through chemotherapy, but enhance the generation of hydrogen peroxide. CuNCs carriers had the properties of Fenton-like activity to realize chemodynamic therapy (CDT) and oxidase-like activity to deplete intracellular glutathione (GSH). Additionally, the chemotherapy drug susceptibility increased owing to the GSH depletion and the outbreak of reactive oxygen species, indicating the enhanced CDT efficacy and amplified chemotherapy efficacy. It was also noteworthy that Ce6 could be activated by 660 nm light to produce abundant singlet oxygen for photodynamic therapy. Overall, our platform demonstrated excellent biosafety and tumor suppression capabilities. This multimodal theranostic strategy provided new insights into cancer therapy.

Perspectives of metal-organic framework nanosystem to overcome tumor drug resistance

Cancer is one of the most harmful diseases in the world, which causes huge numbers of deaths every year. Many drugs have been developed to treat tumors. However, drug resistance usually develops after a period of time, which greatly weakens the therapeutic effect. Tumor drug resistance is characterized by blocking the action of anticancer drugs, resisting apoptosis and DNA repair, and evading immune recognition. To tackle tumor drug resistance, many engineered drug delivery systems (DDS) have been developed. Metal-organic frameworks (MOFs) are one kind of emerging and promising nanocarriers for DDS with high surface area and abundant active sites that make the functionalization simpler and more efficient. These features enable MOFs to achieve advantages easily towards other materials. In this review, we highlight the main mechanisms of tumor drug resistance and the characteristics of MOFs. The applications and opportunities of MOF-based DDS to overcome tumor drug resistance are also discussed, shedding light on the future development of MOFs to address tumor drug resistance.

Hydrogen sulfide activatable metal-organic frameworks for Fluorescence Imaging-Guided Photodynamic Therapy of colorectal cancer

Photodynamic therapy (PDT) is a promising alternative and palliative therapeutic strategy for colorectal cancer (CRC). A novel photosensitizer with higher selectivity for CRC and fewer side effects is vital for clinical application. Given that the overexpression of hydrogen sulfide (H₂S) in CRC, it is expected to provide a selective stimulus for activatable photosensitizers that in respond to the specific microenvironment. Herein, we report a novel development of metal-organic frameworks (MOFs) composed of meso-Tetra (4-carboxyphenyl) porphine (TCPP) and ferric ion (Fe³⁺) through a facile one-pot process. Experiments both in vitro and in vivo reveal that the MOF is capable of depredating in response to the high content of H₂S in tumor microenvironment of CRC. Accompanying with the degradation and release of TCPP, the fluorescence and photosensitivity effect is switched from “off” to “on”, enabling the MOF to serve as a H₂S activatable nano-photosensitizer for real-time fluorescence imaging-guided and targeted PDT of CRC.

Evaluation of lncRNA FOXD3-AS1 as a Biomarker for Early-Stage Lung Cancer Diagnosis and Subtype Identification

Purpose

Lung cancer (LC) is the most commonly diagnosed cancer and the leading cause of cancer-related deaths. More and more long noncoding RNA (lncRNA) are associated with cancer. This study aimed to assess whether plasma lncRNA could be used to diagnose early-stage LC and identify subtypes of LC.

Methods

For bioinformatic analysis, we used genetic data from the Cancer Genome Atlas, lung adenocarcinoma (LUAD), and lung squamous cell carcinoma (LUSC) datasets and a small cell lung cancer (SCLC) dataset from the Gene Expression Omnibus. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to examine the relative expression of lncRNA in LC tissues and plasma samples. The patients' clinical information was obtained at the time of sample collection.

Results

According to public datasets, the lncRNA forkhead box D3 antisense 1 (FOXD3-AS1) was significantly upregulated in LUAD, LUSC, and SCLC tissues over controls. RT-qPCR assays confirmed this finding in LUAD, LUSC, and SCLC tissues and plasma samples. Even early-stage receiver operating characteristic analysis showed that plasma FOXD3-AS1 could be used to discriminate LUAD, LUSC, and SCLC from normal controls and identify LC subtypes SCLC.

Conclusion

FOXD3-AS1 is significantly upregulated in LC tissues and plasma. FOXD3-AS1 could be a potential biomarker for LC subtype identification and early diagnosis.

Membrane disruption boosts iron overload and endogenous oxidative stress to inactivate Escherichia coli by nanoscale zero-valent iron

The inactivation of microorganisms by nanoscale zero-valent iron (nZVI) was extensively reported, but what happens inside the cells is rarely explored. Herein, we revealed that nZVI caused the drastic increase of intracellular iron concentrations, which subsequently catalyzed the Haber-Weiss reaction to produce high levels of endogenous reactive oxygen species (ROSs) and inactivated E. coli cells by oxidative damage of DNA, evidenced by the significantly higher inactivation efficiencies of E. coli mutant strains deficient in iron uptake regulation and DNA repair than the parental strain. The intracellular iron levels, endogenous ROSs levels and the inactivation efficiencies of E. coli were positively correlated. The permeabilized cytomembrane due to the close contact between nZVI and E. coli was responsible for the iron overload. This work demonstrates experimentally for the first time that nZVI causes iron overload and endogenous oxidative stress to inactivate E. coli, thus deepening our knowledge of the nZVI antimicrobial mechanism.

High Drug Capacity Doxorubicin-Loaded Iron Oxide Nanocomposites for Cancer Therapy

Magnetic nanoparticles (MNPs) have great potential in the drug delivery area. Iron oxide (Fe3O4) MNPs have demonstrated a promising effect due to their ferrimagnetic properties, large surface area, stability, low cost, easy synthesis, and functionalization. Some coating procedures are required to improve stability, biocompatibility, and decrease toxicity for medical applications. Herein, the co-precipitation synthesis of iron oxide MNPs coated with four types of primary surfactants, polyethylene glycol 2000 (PEG 2000), oleic acid (OA), Tween 20 (Tw20), and Tween 80 (Tw80), were investigated. Dynamic light scattering (DLS), ζ-potential, and transmission electron microscopy (TEM) techniques were used for morphology, size, charge, and stability analysis. Methylene blue reactive oxygen species (ROS) detection assay and the toxicity experiment on the lung adenocarcinoma A549 cell line were conducted. Two loading conditions for anticancer drug doxorubicin (DOX) on MNPs were proposed. The first one provides high loading efficiency (~90%) with up to 870 μg/mg (DOX/MNPs) drug capacity. The second is perspective for extremely high capacity 1757 μg/mg with drug wasting (DOX loading efficiency ~24%). For the most perspective MNP_OA and MNP_OA_DOX in cell media, pH 7.4, 5, and 3, the stability experiments are also presented. MNP_OA_DOX shows DOX pH-dependent release in the acidic pH and effective inhibition of A549 cancer cell growth. The IC50 values were calculated as 1.13 ± 0.02 mM in terms of doxorubicin and 0.4 ± 0.03 µg/mL in terms of the amount of the nanoparticles. Considering this, the MNP_OA_DOX nano theranostics agent is a highly potential candidate for cancer treatment.