Folate-PEG-PROTAC Micelles for Enhancing Tumor-Specific Targeting Proteolysis In Vivo.

Proteolysis targeting chimeras (PROTACs) technology is rapidly developed as a novel and selective medicinal strategy for the degradation of cellular proteins in cancer therapy. However, the applications of PROTACs as heterobifunctional molecules are largely limited by high molecular weight, low bioavailability, poor permeability, insufficient targeting, and low efficacy in vivo. Herein, self-assembling micelles of FA-PEG-PROTAC are designed for cancer cell selective targeting and reductive-response proteolysis in tumor-bearing mice. FA-PEG-PROTAC is prepared by conjugating folic acid (FA)-PEG with EGFR-targeting PROTAC via a disulfide bond. The FA-PEG-PROTAC micelles, formed by self-assembling, are demonstrated to significantly improve tumor targeting efficacy and exhibit excellent anti-tumor efficacy in the mouse xenograft model compared to the traditional PROTACs. The strategy of applying self-assembled FA-PEG-PROTAC micelles in tumor therapy can not only improve targeted proteolysis efficiency but also broaden applications in the development of PROTAC-based drugs.

Synthesis of novel DOTA-/AAZTA-based bifunctional chelators: Solution thermodynamics, peptidomimetic conjugation, and radiopharmaceutical evaluation.

Bifunctional chelators (BFCs), which link metallic radionuclide and a targeting vector, are some of the most crucial components of metallic radionuclide-based radiopharmaceuticals for positron-emission computed tomography (PET) imaging. In this study, we designed and synthesized two versatile BFCs, p-NCS-Ph-DE4TA and p-NCS-Ph-AAZ4TA, and we conjugated them with a prostate-specific membrane antigen (PSMA) inhibitor. These two chelators showed high affinity for Ga (III) according to a study of the thermodynamics and kinetics and DFT calculations. The labeled PSMA targeted probes, [68Ga]Ga-p-NCS-Ph-DE4TA-PSMA and [68Ga]Ga-p-NCS-Ph-AAZ4TA-PSMA, maintained excellent stability in vitro, and they exhibited high specific activity when binding to PSMA. A PET/CT imaging study in mice bearing SMMC-7721 hepatocellular carcinoma xenografts demonstrated clear visualization of tumors with a high tumor uptake and low background level, indicating the excellent performance in vivo and specific activity when targeting hepatocellular carcinomas. In summary, p-NCS-Ph-DE4TA and p-NCS-Ph-AAZ4TA are leading developmental candidates for PET imaging for tumor diagnosis.

HIF-1 inhibitor-based one-stone-two-birds strategy for enhanced cancer chemodynamic-immunotherapy.

Based on its ability to induce strong immunogenic cell death (ICD), chemodynamic therapy (CDT) was elaborately designed to combine with immunotherapy for a synergistic anticancer effect. However, hypoxic cancer cells can adaptively regulate hypoxia-inducible factor-1 (HIF-1) pathways, leading to a reactive oxygen species (ROS)-homeostatic and immunosuppressive tumor microenvironment. Consequently, both ROS-dependent CDT efficacy and immunotherapy are largely diminished, further lowering their synergy. Here, a liposomal nanoformulation co-delivering a Fenton catalyst copper oleate and a HIF-1 inhibitor acriflavine (ACF) was reported for breast cancer treatment. Through in vitro and in vivo experiments, copper oleate-initiated CDT was proven to be reinforced by ACF through HIF-1-glutathione pathway inhibition, thus amplifying ICD for better immunotherapeutic outcomes. Meanwhile, ACF as an immunoadjuvant significantly reduced the levels of lactate and adenosine, and downregulated the expression of programmed death ligand-1 (PD-L1), thereby promoting the antitumor immune response in a CDT-independent manner. Hence, the "one stone" ACF was fully taken advantage of to enhance CDT and immunotherapy (two birds), both of which contributed to a better therapeutic outcome.

Preparation and In Vitro Evaluation of a Gadolinium-Containing Vitamin E TPGS Micelle as a Potential Contrast Agent for MR Imaging.

The application of many currently evaluated macromolecular contrast agents for magnetic resonance imaging (MRI) has been limited because of their bio-incompatibility and toxicity. The aim of this study is to synthesize and characterize a new micelle-based TPGS gadolinium chelate as a biocompatible MRI contrast agent for prolonged blood circulation time and good tumor imaging contrast. The TPGS-gadolinium conjugate was prepared through the conjugation between TPGS-SA and bifunctional L-NETA-Gd chelate. The conjugate was characterized with regard to molecular weight, critical micellar concentration and particle sizes, cellular uptake, and in vitro cell MRI. Distributions of the MRI contrast agent in various organs were determined via intravenous injection of the agent into mice bearing xenograft tumors. The successfully prepared TPGS-L-NETA-Gd micelle exhibited improved cellular uptake in HepG2 cells and xenografts and high in vivo safety. Distributions of TPGS-L-NETA-Gd in mice showed enhanced cellular uptake up to 2 h after the contrast agent injection. Its in vitro and in vivo properties make it a favorable macromolecular MRI contrast agent for future in vivo imaging.

Biomimetic calcium carbonate nanoparticles delivered IL-12 mRNA for targeted glioblastoma sono-immunotherapy by ultrasound-induced necroptosis.

Glioblastoma (GBM) is the most aggressive brain tumor, which owns the characteristics of high recurrence, low survival rate and poor prognosis because of the existence of blood brain barrier (BBB) and complicated brain tumor microenvironment. Currently, immunotherapy has attracted much attention on account of favorable therapeutic effect. In this study, we designed a cRGD-modified cancer cell membrane (CM) coated calcium carbonate nanoparticle to deliver interleukin-12 messenger RNA (IL-12 mRNA@cRGD-CM-CaCO3 NPs). The cRGD-modified CM as the shell can endow the nanoparticles with BBB crossing and tumor homing/homotypic targeting effect in the brain tumor microenvironment. IL-12 mRNA-loaded calcium carbonate nanoparticles as the core allow synergistic immunotherapy of necroptosis-induced immune response and IL-12 mRNA transfection under ultrasound irradiation. The as-prepared biomimetic nanoparticles showed superior target and immunotherapeutic outcomes, suggesting that this biomimetic nanoplatform provides a feasible strategy for promoting BBB-penetrating and antitumor immunity.

Nanoscale CaO2 materials for synergistic transarterial chemoembolization in a VX2 orthotopic rabbit liver cancer model.

Transcatheter arterial chemoembolization (TACE) is extensively used in the treatment of hepatocellular carcinoma (HCC), but its efficacy is usually limited to secondary tumor hypoxia and other progressive exacerbation of the abnormal tumor microenvironment (TME). Herein, we synthesized polyvinyl pyrrolidone (PVP)-coated CaO2 nanoparticles (CaO2 NPs) and applied them as a synergistic agent to improve the antitumor efficacy of TACE. After injection into the tumor, CaO2 NPs reacted with water to generate abundant oxygen, hydroxyl ions (OH-), and calcium ions (Ca2+), thereby relieving tumor hypoxia, neutralizing acid, and overloading Ca2+ to mediate antitumor effects. Moreover, the effect of chemotherapeutic drugs within the TACE was improved due to the modulated TME. CaO2 NPs efficiently regulated the TME and improved the antitumor effect of doxorubicin under hypoxia conditions in vitro. Compared to other groups, the TACE+CaO2 NPs group achieved the lowest tumor growth rate, highest tumor necrosis rate, lowest expression of histological markers associated with hypoxia and angiogenesis (HIF-α, VEGF, and CD31), and highest CD8+ T cell recruitment in vivo. Thus, these findings demonstrated that CaO2 NPs provide synergy for TACE therapy in the VX2 orthotopic rabbit liver cancer model, suggesting that they have a potential broad clinical application. STATEMENT OF SIGNIFICANCE: The efficacy of transcatheter arterial chemoembolization (TACE) for treatment of hepatocellular carcinoma is usually limited to secondary tumor hypoxia and other progressive exacerbation of the abnormal tumor microenvironment (TME). To address this issue, we synthesized CaO2 nanoparticles (CaO2 NPS) which would react with water to generate abundant oxygen, hydroxyl ions (OH-), and calcium ions (Ca2+), thereby relieving tumor hypoxia, neutralizing the acidic TME, and inducing Ca2+ overloading. The efficacy of CaO2 NPs in combination with TACE was investigated in an orthotopic rabbit liver cancer model, and the results showed the great synergetic antitumor effect of TACE and CaO2 NPs.

Design, synthesis, and molecular docking studies of novel pomalidomide-based PROTACs as potential anti-cancer agents targeting EGFRWT and EGFRT790M.

A new class of EGFR PROTACs based on pomalidomide was developed, synthesised, and tested for their cytotoxic activity against a panel of human cancer cells. Compounds 15-21 were showed to be more effective against the four tested cell lines than erlotinib. In particular, compound 16 was found to be the most potent counterpart as it was 5.55, 4.34, 5.04, and 7.18 times more active than erlotinib against MCF-7, HepG-2, HCT-116, and A549 cells, respectively. Compound 15 was revealed to be more active than doxorubicin against the four tested cell lines. Furthermore, the most potent cytotoxic compounds were studied further for their kinase inhibitory effects against EGFRWT and EGFRT790M using HTRF test. Compound 16 showed to be the most effective against both kinds of EGFR, with IC50 values of 0.10 and 4.02 µM, respectively. Compound 16 could effectively degrade EGFR protein through ubiquitination (Dmax = 96%) at 72 h in the tested cells.

Synthesis of a new bifunctional NODA for bioconjugation with PSMA ligand and one-step Al18F labeling.

The Al18F labeling method is a relatively new approach that allows radiofluorination of biomolecules such as peptides and proteins in a one-step procedure and in an aqueous solution. However, instability of the complex of [AlF]2+ with hexadentate chelator NOTA may attribute to the disassociation of free 18F- and [Al18F]2+ and accumulation in bone. In this study, we designed and synthesized a new bifunctional pentadentate AlF-chelator p-SCN-PhPr-NODA as well as its nitro form p-NO2-PhPr-NODA. Chelator p-NO2-PhPr-NODA exhibited increased Al (III) complexation kinetics determined by AA III complexation kinetic studies and stronger coordination ability towards [AlF]2+ according to DFT calculation studies in comparison with hexadentate chelator NOTA. As a proof of concept, bifunctional chelator p-SCN-PhPr-NODA was furthermore conjugated to a PSMA targeting moiety Glu-urea-Lys to form NODA-PrPh-GuL. The conjugated peptide showed acceptable radiochemical yield (12.5-16.4%) and efficiency with an excellent radiochemical purity (∼100% after SPE purification) in Al18F labeling. The labeled peptide exhibited good in vitro stability and significant specificity for PSMA. Biodistribution study and MicroPET scan in healthy Kun Ming mice with the labeled peptide were performed and demonstrated excellent in vivo stability of Al18F-labeled construct. In general, the successful application of the new bifunctional chelator in labeling dipeptide Glu-urea-Lys with Al18F could facilitate its possibility in conjugating with other peptides for PET imaging with enhanced in vivo stability, thus providing better in vivo performances.

Synthesis and evaluation of novel 1,4,7-triazacyclononane derivatives as Cu2+ and Ga3+ chelators.

Advances in chelator design are the cornerstone for the development of metals like copper and gallium based biomedical agents and radiopharmaceuticals. To develop optimal chelating ligands, we explored the synthesis and chelating properties of azaheterocycle pendant armed 1,4,7-triazacyclononane (TACN) dimethylcarboxylate derivatives and dimethylphosphonate derivatives. In the complexation kinetics test, dicarboxylate pendant armed TACN derivatives 2,2'-(7-((1H-imidazol-2-yl)methyl)-1,4,7-triazonane-1,4-diyl)diacetic acid (NODA-Im), 2,2'-(7-((1-methyl-1H-imidazol-2-yl)methyl)-1,4,7-triazonane-1,4-diyl)diacetic acid (NODA-MeIm), and 2,2'-(7-(thiazol-2-ylmethyl)-1,4,7-triazonane-1,4-diyl)diacetic acid (NODA-Thia) exhibited fast complexation kinetics towards Cu (II) cations, which were comparable to the frequently explored ligand 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). And the diphosphonate pendant armed TACN derivative ((7-(thiazol-2-ylmethyl)-1,4,7-triazonane-1,4-diyl)bis(methylene))bis(phosphonic acid) (NODP-Thia) bound with Ga (III) cations at a much faster rate than NOTA. Density functional theory studies confirmed that the better complexation kinetics and metal chelating efficiency of NODA-Im, NODA-MeIm, NODA-Thia, and NODP-Thia could be ascribed to the lower Gibbs energies of corresponding chelator-metal complexes than NOTA-metal complexes. The kinetic inertness of the Cu (II) complex with NODA-Im, NODA-MeIm, and NODA-Thia was also demonstrated by cyclic voltammetry studies. Subsequently radiolabeling experiment demonstrated that these metal chelators could efficiently labeled with 64Cu or 68Ga in good radiochemical purities. These preliminary findings support NODA-Im, NODA-MeIm, NODA-Thia, and NODP-Thia as promising leading chelating agents for the development of bifunctional Cu2+ and Ga3+ chelators in biomedical applications.

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.

A smart O2-generating nanocarrier optimizes drug transportation comprehensively for chemotherapy improving.

Drug transportation is impeded by various barriers in the hypoxic solid tumor, resulting in compromised anticancer efficacy. Herein, a solid lipid monostearin (MS)-coated CaO2/MnO2 nanocarrier was designed to optimize doxorubicin (DOX) transportation comprehensively for chemotherapy enhancement. The MS shell of nanoparticles could be destroyed selectively by highly-expressed lipase within cancer cells, exposing water-sensitive cores to release DOX and produce O2. After the cancer cell death, the core-exposed nanoparticles could be further liberated and continue to react with water in the tumor extracellular matrix (ECM) and thoroughly release O2 and DOX, which exhibited cytotoxicity to neighboring cells. Small DOX molecules could readily diffuse through ECM, in which the collagen deposition was decreased by O2-mediated hypoxia-inducible factor-1 inhibition, leading to synergistically improved drug penetration. Concurrently, DOX-efflux-associated P-glycoprotein was also inhibited by O2, prolonging drug retention in cancer cells. Overall, the DOX transporting processes from nanoparticles to deep tumor cells including drug release, penetration, and retention were optimized comprehensively, which significantly boosted antitumor benefits.

Nitric oxide-releasing micelles with intelligent targeting for enhanced anti-tumor effect of cisplatin in hypoxia.

BACKGROUND: Hypoxic tumor microenvironment (TME) promotes tumor metastasis and drug resistance, leading to low efficiency of cancer chemotherapy. The development of targeted agents or multi-target therapies regulating hypoxic microenvironment is an important approach to overcome drug resistance and metastasis. METHODS: In this study, chitosan oligosaccharide (COS)-coated and sialic acid (SA) receptor-targeted nano-micelles were prepared using film dispersion method to co-deliver cisplatin (CDDP) and nitric oxide (NO) (denoted as CTP/CDDP). In addition, we explored the mechanisms by which NO reversed CDDP resistance as well as enhanced anti-metastatic efficacy in hypoxic cancer cells. RESULTS: Because of the different affinities of COS and SA to phenylboronic acid (PBA) under different pH regimes, CTP/CDDP micelles with intelligent targeting property increased cellular uptake of CDDP and enhanced cytotoxicity to tumors, but reduced systemic toxicity to normal organs or tissues. In addition, CTP/CDDP showed stimulus-responsive release in TME. In terms of anti-tumor mechanism, CTP/CDDP reduced CDDP efflux and inhibited epithelial-mesenchymal transition (EMT) process of tumor by down-regulating hypoxia-inducible factor-1α (HIF-1α), glutathione (GSH), multidrug resistance-associated protein 2 (MRP2) and matrix metalloproteinase 9 (MMP9) expression, thus reversing drug resistance and metastasis of hypoxic tumor cells. CONCLUSIONS: The designed micelles significantly enhanced anti-tumor effects both in vitro and in vivo. These results suggested that CTP/CDDP represented a promising strategy to treat resistance and metastatic tumors.

Nanoparticle-Assisted Sonosensitizers and Their Biomedical Applications.

As a non-invasive strategy, sonodynamic therapy (SDT) which utilizes sonosensitizers to generate reactive oxygen species (ROS) has received significant interest over recent years due to its ability to break depth barrier. However, intrinsic limitations of traditional sonosensitizers hinder the widespread application of SDT. With the development of nanotechnology, various nanoparticles (NPs) have been designed and used to assist sonosensitizers for SDT. This review first summarizes the possible mechanisms of SDT, then classifies the NPs-assisted sonosensitizers and discusses their biomedical applications in ultrasonography, drug delivery, high intensity focused ultrasound and SDT-based combination treatment. Finally, some challenges and future perspectives of NPs-assisted SDT has also been discussed.

Cyclic reactions-mediated self-supply of H2O2 and O2 for cooperative chemodynamic/starvation cancer therapy.

Hydroxyl radical (·OH)-mediated chemodynamic therapy (CDT) and glucose oxidase (GOx)-based starvation therapy (ST) are two emerging antitumor strategies, limited by acid/H2O2 deficiency and tumor hypoxia, respectively. Herein, we developed a liposomal nanoplatform co-delivering Fe(OH)3-doped CaO2 nanocomposites and GOx molecules for synergistic CDT/ST with a complementary effect. Based on Fenton reactions initiated by iron ions, CaO2-supplied H2O2 could not only generate ·OH for H2O2-sufficient CDT, but also produce O2 to promote the catalytic efficiency of GOx under hypoxia. In return, the enhanced ST generated gluconic acid and H2O2, further amplifying CDT. Through in vitro and in vivo experiments, we demonstrated that such a mutually reinforced modality based on the cyclic Fenton/starvation reactions provided a novel and potent anticancer mechanism for the effective treatment of hypoxic cancers.

A solid lipid coated calcium peroxide nanocarrier enables combined cancer chemo/chemodynamic therapy with O2/H2O2 self-sufficiency.

The unfavorable factors in tumor microenvironment such as hypoxia and limited H2O2 levels greatly impede the anticancer efficacy of chemotherapy and chemodynamic therapy (CDT). To address these issues and achieve O2/H2O2-sufficient chemo/chemodynamic combination therapy, we synthesized a solid lipid monostearin coated calcium peroxide (CaO2) nanocarrier for the co-delivery of a chemotherapeutic drug doxorubicin (DOX) and a biocompatible Fenton catalyst iron-oleate complex. Specifically, the solid lipid shells of nanoparticles could disintegrate in lipase-overexpressed cancer cells to release iron-oleate and expose CaO2 cores. Afterwards, the uncovered CaO2 responded to the acidic aqueous environment within cancer cells, leading to the release of DOX molecules and generation of H2O2. Based on Fenton reactions, Fe3+ liberated from iron-oleate reacted with H2O2 to produce O2 for hypoxia-relieved chemotherapy, and Fe2+ for the catalytic generation of hydroxyl radical to initiate CDT. Both treatments synergistically contribute to the enhanced antitumor outcomes.

Recent advances of antibody drug conjugates for clinical applications.

Antibody drug conjugates (ADCs) normally compose of a humanized antibody and small molecular drug via a chemical linker. After decades of preclinical and clinical studies, a series of ADCs have been widely used for treating specific tumor types in the clinic such as brentuximab vedotin (Adcetris®) for relapsed Hodgkin's lymphoma and systemic anaplastic large cell lymphoma, gemtuzumab ozogamicin (Mylotarg®) for acute myeloid leukemia, ado-trastuzumab emtansine (Kadcyla®) for HER2-positive metastatic breast cancer, inotuzumab ozogamicin (Besponsa®) and most recently polatuzumab vedotin-piiq (Polivy®) for B cell malignancies. More than eighty ADCs have been investigated in different clinical stages from approximately six hundred clinical trials to date. This review summarizes the key elements of ADCs and highlights recent advances of ADCs, as well as important lessons learned from clinical data, and future directions.

Nanoparticle facilitated delivery of peroxides for effective cancer treatments.

Through the utilization of hydrogen peroxide (H2O2) in cancer cells, nanoparticle-facilitated catalytic generation of therapeutic molecules such as O2 and hydroxyl radicals enabled enhanced anticancer efficacy of O2 or reactive oxygen species-dependent therapies. However, the intracellular H2O2 was inadequate to obtain satisfactory therapeutic outcomes. Although several reagents such as glucose oxidase and cisplatin could promote H2O2 levels by O2 conversion, H2O2-mediated therapeutic efficacy was still hindered in the hypoxic tumor microenvironment. Fortunately, exogenous delivery of H2O2 or other peroxides to tumor sites was able to break the limitation of intracellular O2 and H2O2 levels and enhance anti-tumor effects. In this review, we summarize the recent progress in constructing a peroxide delivery system for cancer treatments and discuss their challenges and potential applications.

Platinum complexes of curcumin delivered by dual-responsive polymeric nanoparticles improve chemotherapeutic efficacy based on the enhanced anti-metastasis activity and reduce side effects.

Platinum-based chemotherapy is used for non-small cell lung cancer (NSCLC). However, it has side effects and minimum efficacy against lung cancer metastasis. In this study, platinum-curcumin complexes were loaded into pH and redox dual-responsive nanoparticles (denoted as Pt-CUR@PSPPN) to facilitate intracellular release and synergistic anti-cancer effects. Pt-CUR@PSPPN was prepared by a nano-precipitation method and had a diameter of ∼100 nm. The nanoparticles showed increased anti-cancer effects both in vivo and in vitro. In addition, Pt-CUR@PSPPN blocked PI3K/AKT signal transduction pathway and inhibited MMP2 and VEGFR2, resulting in enhanced anti-metastatic activity. Furthermore, reduced side effects were also observed. In conclusion, Pt-CUR@PSPPN provided a novel and attractive therapeutic strategy for NSCLC.

Nano Encapsulated Curcumin: And Its Potential for Biomedical Applications.

Curcumin, a yellow-colored polyphenol extracted from the rhizome of turmeric root, is commonly used as a spice and nutritional supplement. It exhibits many pharmacological activities such as anti-inflammatory, anti-bacterial, anti-cancer, anti-Alzheimer, and anti-fungal. However, the therapeutic application of curcumin is limited by its extremely low solubility in aqueous buffer, instability in body fluids, and rapid metabolism. Nano delivery system has shown excellent potential to improve the solubility, biocompatibility and therapeutic effect of curcumin. In this review, we focus on the recent development of nano encapsulated curcumin and its potential for biomedical applications.

One-pot synthesis of a microporous organosilica-coated cisplatin nanoplatform for HIF-1-targeted combination cancer therapy.

Nanoparticle formulations have proven effective for cisplatin delivery. However, the development of a versatile nanoplatform for cisplatin-based combination cancer therapies still remains a great challenge. Methods: In this study, we developed a one-pot synthesis method for a microporous organosilica shell-coated cisplatin nanoplatform using a reverse microemulsion method, and explored its application in co-delivering acriflavine (ACF) for inhibiting hypoxia-inducible factor-1 (HIF-1). Results: The resulting nanoparticles were tunable, and they could be optimized to a monodisperse population of particles in the desired size range (40-50 nm). In addition, organic mPEG2000-silane and tetrasulfide bond-bridged organosilica were integrated into the surface and silica matrix of nanoparticles for prolonged blood circulation and tumor-selective glutathione-responsive degradation, respectively. After reaching the tumor sites, cisplatin induced cancer cell death and activated HIF-1 pathways, resulting in acquired drug resistance and tumor metastasis. To address this issue, ACF was co-loaded with cisplatin to prevent the formation of HIF-1α/ß dimers and suppress HIF-1 function. Hence, the efficacy of cisplatin was improved, and cancer metastasis was inhibited. Conclusion: Both in vitro and in vivo results suggested that this core-shell nanostructured cisplatin delivery system represented a highly efficacious and promising nanoplatform for the synergistic delivery of combination therapies involving cisplatin.