bims-drudre Biomed News
on Targeted drug delivery and programmed release mechanisms
Issue of 2021‒02‒28
sixteen papers selected by
Ceren Kimna
Technical University of Munich

  1. Nature. 2021 Feb 24.
      Regulatory T cells (Treg cells) are essential for immune tolerance1, but also drive immunosuppression in the tumour microenvironment2. Therapeutic targeting of Treg cells in cancer will therefore require the identification of context-specific mechanisms that affect their function. Here we show that inhibiting lipid synthesis and metabolic signalling that are dependent on sterol-regulatory-element-binding proteins (SREBPs) in Treg cells unleashes effective antitumour immune responses without autoimmune toxicity. We find that the activity of SREBPs is upregulated in intratumoral Treg cells. Moreover, deletion of SREBP-cleavage-activating protein (SCAP)-a factor required for SREBP activity-in these cells inhibits tumour growth and boosts immunotherapy that is triggered by targeting the immune-checkpoint protein PD-1. These effects of SCAP deletion are associated with uncontrolled production of interferon-γ and impaired function of intratumoral Treg cells. Mechanistically, signalling through SCAP and SREBPs coordinates cellular programs for lipid synthesis and inhibitory receptor signalling in these cells. First, de novo fatty-acid synthesis mediated by fatty-acid synthase (FASN) contributes to functional maturation of Treg cells, and loss of FASN from Treg cells inhibits tumour growth. Second, Treg cells in tumours show enhanced expression of the PD-1 gene, through a process that depends on SREBP activity and signals via mevalonate metabolism to protein geranylgeranylation. Blocking PD-1 or SREBP signalling results in dysregulated activation of phosphatidylinositol-3-kinase in intratumoral Treg cells. Our findings show that metabolic reprogramming enforces the functional specialization of Treg cells in tumours, pointing to new ways of targeting these cells for cancer therapy.
  2. Nucleic Acids Res. 2021 Feb 22. pii: gkab100. [Epub ahead of print]
      CRISPR technologies increasingly require spatiotemporal and dosage control of nuclease activity. One promising strategy involves linking nuclease activity to a cell's transcriptional state by engineering guide RNAs (gRNAs) to function only after complexing with a 'trigger' RNA. However, standard gRNA switch designs do not allow independent selection of trigger and guide sequences, limiting gRNA switch application. Here, we demonstrate the modular design of Cas12a gRNA switches that decouples selection of these sequences. The 5' end of the Cas12a gRNA is fused to two distinct and non-overlapping domains: one base pairs with the gRNA repeat, blocking formation of a hairpin required for Cas12a recognition; the other hybridizes to the RNA trigger, stimulating refolding of the gRNA repeat and subsequent gRNA-dependent Cas12a activity. Using a cell-free transcription-translation system and Escherichia coli, we show that designed gRNA switches can respond to different triggers and target different DNA sequences. Modulating the length and composition of the sensory domain altered gRNA switch performance. Finally, gRNA switches could be designed to sense endogenous RNAs expressed only under specific growth conditions, rendering Cas12a targeting activity dependent on cellular metabolism and stress. Our design framework thus further enables tethering of CRISPR activities to cellular states.
  3. Sci Adv. 2021 Feb;pii: eabf4398. [Epub ahead of print]7(9):
      Ionizable lipid nanoparticles (LNPs) have been widely used for in vivo delivery of RNA therapeutics into the liver. However, a main challenge remains to develop LNP formulations for selective delivery of RNA into certain types of liver cells, such as hepatocytes and liver sinusoidal endothelial cells (LSECs). Here, we report the engineered LNPs for the targeted delivery of RNA into hepatocytes and LSECs. The effects of particle size and polyethylene glycol-lipid content in the LNPs were evaluated for the hepatocyte-specific delivery of mRNA by ApoE-mediated cellular uptake through low-density lipoprotein receptors. Targeted delivery of RNA to LSECs was further investigated using active ligands. Incorporation of mannose allowed the selective delivery of RNA to LSECs, while minimizing the unwanted cellular uptake by hepatocytes. These results demonstrate that engineered LNPs have great potential for the cell type-specific delivery of RNA into the liver and other tissues.
  4. Nano Lett. 2021 Feb 23.
      Nanoscale artificial antigen-presenting cells (aAPCs) are promising to activate T cells directly for cancer immunotherapy, while feasible and flexible strategy to develop nanoscale aAPCs remains highly desirable. Metabolic glycoengineering is used to decorate chemical tags on cells which enables bioorthogonal chemical conjugation of functional molecules. Herein, we develop a nanoscale aAPC by metabolic dendritic cell (DC) labeling to mobilize T-cell based antitumor immunity. We coat azido-labeled DC membrane on imiquimod-loaded polymeric nanoparticles and sequentially modify anti-CD3ε antibody via click chemistry. The nanoscale aAPCs perform improved distribution in lymph nodes and stimulate T cells and resident APCs. Significant inhibition of tumor inoculation and growth is observed after the vaccination, which can be further improved by combining antiprogrammed cell death receptor 1 (PD1) therapy. Our results demonstrate the promising application of metabolically labeled DCs for designing nanoscale aAPCs, which provide a simple and general strategy to potentiate cancer immunotherapy.
    Keywords:  artificial antigen-presenting cells; cancer immunotherapy; dendritic cells; metabolic cell labeling; nanoscale
  5. Adv Mater. 2021 Feb 26. e2008061
      Cell-membrane-coated nanoparticles (CCNPs) that integrate the biophysiological advantages of cell membranes with the multifunctionalities of synthetic materials hold great promise in cancer immunotherapy. However, strategies have yet to be revealed to further improve their immunotherapeutic efficacy. Herein, a polymer multicellular nanoengager (SPNE) for synergistic second-near-infrared-window (NIR-II) photothermal immunotherapy is reported. The nanoengager consists of an NIR-II absorbing polymer as the photothermal core, which is camouflaged with fused membranes derived from immunologically engineered tumor cells and dendritic cells (DCs) as the cancer vaccine shell. In association with the high accumulation in lymph nodes and tumors, the multicellular engagement ability of the SPNE enables effective cross-interactions among tumor cells, DCs, and T cells, leading to augmented T cell activation relative to bare or tumor-cell-coated nanoparticles. Upon deep-tissue penetrating NIR-II photoirradiation, SPNE eradicates the tumor and induces immunogenic cell death, further eliciting anti-tumor T cell immunity. Such a synergistic photothermal immunotherapeutic effect eventually inhibits tumor growth, prevents metastasis and procures immunological memory. Thus, this study presents a general cell-membrane-coating approach to develop photo-immunotherapeutic agents for cancer therapy.
    Keywords:  immunotherapy; polymer nanoparticles; second near-infrared photothermal therapy; tumor therapy
  6. Sci Adv. 2021 Feb;pii: eabe3348. [Epub ahead of print]7(9):
      CD4 T cells have been implicated in cancer immunity for their helper functions. Moreover, their direct cytotoxic potential has been shown in some patients with cancer. Here, by mining single-cell RNA-seq datasets, we identified CD4 T cell clusters displaying cytotoxic phenotypes in different human cancers, resembling CD8 T cell profiles. Using the peptide-MHCII-multimer technology, we confirmed ex vivo the presence of cytolytic tumor-specific CD4 T cells. We performed an integrated phenotypic and functional characterization of these cells, down to the single-cell level, through a high-throughput nanobiochip consisting of massive arrays of picowells and machine learning. We demonstrated a direct, contact-, and granzyme-dependent cytotoxic activity against tumors, with delayed kinetics compared to classical cytotoxic lymphocytes. Last, we found that this cytotoxic activity was in part dependent on SLAMF7. Agonistic engagement of SLAMF7 enhanced cytotoxicity of tumor-specific CD4 T cells, suggesting that targeting these cells might prove synergistic with other cancer immunotherapies.
  7. ACS Nano. 2021 Feb 24.
      Hypoxia is a critical cause of tumor immunosuppression, and it significantly limits the efficacy of many anticancer modalities. Herein, we report an amphiphilic F11-derivative-based oxygen-delivering polyfluorocarbon nanovehicle loading photodynamic DiIC18(5) and reactive oxygen species (ROS)-sensitive prodrug of chemo-immunomodulatory gemcitabine (PF11DG), aimed at relieving tumor hypoxia and boosting antitumor immunity for cancer therapy. We optimized F11-based polyfluorocarbon nanovehicles with a 10-fold enhancement of tumor oxygenation. PF11DG exhibited intriguing capabilities, such as oxygen-dissolving, ROS production, and responsive drug release. In tumors, PF11DG exhibited flexible intratumoral permeation and boosted robust antitumor immune responses upon laser irradiation. Notably, the treatment of PF11DG plus laser irradiation (PF11DG+L) significantly retarded the tumor growth with an 82.96% inhibition in the 4T1 breast cancer model and a 93.6% inhibition in the PANC02 pancreatic cancer model with better therapeutic benefits than non-oxygen-delivering nanovehicles. Therefore, this study presents an encouraging polyfluorocarbon nanovehicle with deep tumor-penetrating and hypoxia-relieving capacity to boost antitumor immunity for cancer treatment.
    Keywords:  antitumor immunity; nanovehicle; oxygen; polyfluorocarbon; tumor hypoxia
  8. Sci Adv. 2021 Feb;pii: eabe5914. [Epub ahead of print]7(9):
      Swarming micro/nanorobots offer great promise in performing targeted delivery inside diverse hard-to-reach environments. However, swarm navigation in dynamic environments challenges delivery capability and real-time swarm localization. Here, we report a strategy to navigate a nanoparticle microswarm in real time under ultrasound Doppler imaging guidance for active endovascular delivery. A magnetic microswarm was formed and navigated near the boundary of vessels, where the reduced drag of blood flow and strong interactions between nanoparticles enable upstream and downstream navigation in flowing blood (mean velocity up to 40.8 mm/s). The microswarm-induced three-dimensional blood flow enables Doppler imaging from multiple viewing configurations and real-time tracking in different environments (i.e., stagnant, flowing blood, and pulsatile flow). We also demonstrate the ultrasound Doppler-guided swarm formation and navigation in the porcine coronary artery ex vivo. Our strategy presents a promising connection between swarm control and real-time imaging of microrobotic swarms for localized delivery in dynamic environments.
  9. Mol Ther Nucleic Acids. 2021 Mar 05. 23 835-846
      Colorectal cancer (CRC) is a commonly diagnosed cancer with poor prognosis and high mortality rate. Hyperthermia (HT) is an adjunctive therapy to enhance the antitumor effects of traditional chemo- or radio- therapy. Here, we report that a cluster of essential regulator genes and speed-limit enzymes of glucose metabolism were significantly elevated under HT from a glucose metabolism PCR array analysis. Under low glucose supply or glucose metabolism inhibition, CRC cells displayed increased sensitivity to HT treatments. By transcript sequencing from the established HT resistant (HTR) colon cancer cell line LoVo HTR, we observed that IGF2BP1, an RNA-binding protein, was significantly upregulated in HTR cells compared with parental cells. Furthermore, LDHA mRNA was identified as an IGF2BP1 direct target. An RNA immunoprecipitation assay and RNA pull-down assay consistently illustrated IGF2BP1 specifically bonds to the 3' UTR of LDHA mRNA, leading to enhanced stability of LDHA mRNA. Finally, we demonstrated that inhibiting the IGF2BP1-promoted glycolysis sensitized colon cancer cells to HT treatment via both in vitro and in vivo experiments. Our findings suggest that targeting the IGF2BP1-LDHA-glycolysis pathway might be a promising therapeutic approach to enhance the anti-cancer effects of HT treatment.
    Keywords:  IGF2BP1; LHDA; RNA-binding protein; Warburg effect; glucose metabolism; mild HT
  10. Sci Adv. 2021 Feb;pii: eabd6740. [Epub ahead of print]7(9):
      Current therapeutic strategies such as angiogenic therapy and anti-inflammatory therapy for treating myocardial infarction have limited success. An effective approach may benefit from resolution of excessive inflammation combined with enhancement of angiogenesis. Here, we developed a microRNA-21-5p delivery system using functionalized mesoporous silica nanoparticles (MSNs) with additional intrinsic therapeutic effects. These nanocarriers were encapsulated into an injectable hydrogel matrix (Gel@MSN/miR-21-5p) to enable controlled on-demand microRNA-21 delivery triggered by the local acidic microenvironment. In a porcine model of myocardial infarction, we demonstrated that the released MSN complexes notably inhibited the inflammatory response by inhibiting the polarization of M1 macrophage within the infarcted myocardium, while further microRNA-21-5p delivery by MSNs to endothelial cells markedly promoted local neovascularization and rescued at-risk cardiomyocytes. The synergy of anti-inflammatory and proangiogenic effects effectively reduced infarct size in a porcine model of myocardial infarction.
  11. Proc Natl Acad Sci U S A. 2021 Mar 02. pii: e2018338118. [Epub ahead of print]118(9):
      A vaccine which is effective against the HIV virus is considered to be the best solution to the ongoing global HIV/AIDS epidemic. In the past thirty years, numerous attempts to develop an effective vaccine have been made with little or no success, due, in large part, to the high mutability of the virus. More recent studies showed that a vaccine able to elicit broadly neutralizing antibodies (bnAbs), that is, antibodies that can neutralize a high fraction of global virus variants, has promise to protect against HIV. Such a vaccine has been proposed to involve at least three separate stages: First, activate the appropriate precursor B cells; second, shepherd affinity maturation along pathways toward bnAbs; and, third, polish the Ab response to bind with high affinity to diverse HIV envelopes (Env). This final stage may require immunization with a mixture of Envs. In this paper, we set up a framework based on theory and modeling to design optimal panels of antigens to use in such a mixture. The designed antigens are characterized experimentally and are shown to be stable and to be recognized by known HIV antibodies.
    Keywords:  HIV; broadly neutralizing antibodies; vaccine design
  12. Adv Mater. 2021 Feb 26. e2006177
      Light-driven directional motion is common in nature but remains a challenge for synthetic microparticles, particularly regarding collective motion on a macroscopic scale. Successfully engineering microparticles with light-driven collective motion could lead to breakthroughs in drug delivery, contaminant sensing, environmental remediation, and artificial life. Herein, metal-phenolic particle microswimmers capable of autonomously sensing and swimming toward an external light source are reported, with the speed regulated by the wavelength and intensity of illumination. These microswimmers can travel macroscopic distances (centimeters) and can remain illuminated for hours without degradation of motility. Experimental and theoretical analyses demonstrate that motion is generated through chemical transformations of the organic component of the metal-phenolic complex. Furthermore, cargos with specific spectral absorption profiles can be loaded into the particles and endow the particle microswimmers with activated motion corresponding to these spectral characteristics. The programmable nature of the light navigation, tunable size of the particles, and versatility of cargo loading demonstrate the versatility of these metal-phenolic particle microswimmers.
    Keywords:  cargo loading; light-driven microswimmers; micromotors; spectral response; tunable speed
  13. Nano Lett. 2021 Feb 26.
      The codelivery of drugs at specific optimal ratios to cancer cells is vital for combination chemotherapy. However, most of the current strategies are unable to coordinate the loading and release of drug combinations to acquire precise and controllable synergistic ratios. In this work, we designed an innovative dual-drug backboned and reduction-sensitive polyprodrug PEG-P(MTO-ss-CUR) containing the anticancer drugs mitoxantrone (MTO) and curcumin (CUR) at an optimal synergistic ratio to reverse drug resistance. Due to synchronous drug activation and polymer backbone degradation, drug release at the predefined ratio with a synergistic anticancer effect was demonstrated by in vitro and in vivo experiments. Therefore, the dual-drug delivery system developed in this work provides a novel and efficient strategy for combination chemotherapy.
    Keywords:  combination chemotherapy; curcumin; mitoxantrone; polyprodrug
  14. ACS Nano. 2021 Feb 24.
      Morphology genetic biomedical materials (MGBMs), referring to fabricating materials by learning from the genetic morphologies and strategies of natural species, hold great potential for biomedical applications. Inspired by the cargo-carrying-bacterial therapy (microbots) for cancer treatment, a MGBM (artificial microbots, AMBs) was constructed. Rather than the inherent bacterial properties (cancerous chemotaxis, tumor invasion, cytotoxicity), AMBs also possessed ingenious nitric oxide (NO) generation strategy. Mimicking the bacterial construction, the hyaluronic acid (HA) polysaccharide was induced as a coating capsule of AMBs to achieve long circulation in blood and specific tissue preference (tumor tropism). Covered under the capsule-like polysaccharide was the combinatorial agent, the self-assembly constructed by the amphiphilic dendrons with abundant l-arginine residues peripherally (as endogenous NO donor) and hydrophobic chemotherapeutic drugs at the core stacking on the surface of SWNTs (the photothermal agent) for a robust chemo-photothermal therapy (chemo-PTT) and the elicited immune therapy. Subsequently, the classic inducible nitric oxide synthase (iNOS) pathway aroused by immune response was revolutionarily utilized to oxidize the l-arginine substrates for NO production, the process for which could also be promoted by the high reactive oxygen species level generated by chemo-PTT. The NO generated by AMBs was intended to regulate vasodilation and cause a dramatic invasion (as the microbots) to disperse the therapeutic agents throughout the solid tumor for a much more enhanced curative effect, which we defined as "self-propulsion". The self-propelled AMBs exhibiting impressive primary tumor ablation, as well as the distant metastasis regression to conquer the metastatic triple negative breast cancer, provided pioneering potential therapeutic opportunities, and enlightened broad prospects in biomedical application.
    Keywords:  artificial microbots; metastasis; morphology genetic biomedical materials; nitric oxide; self-propulsion
  15. Adv Mater. 2021 Jan;33(4): e2002047
      Micro-/nanorobots (m-bots) have attracted significant interest due to their suitability for applications in biomedical engineering and environmental remediation. Particularly, their applications in in vivo diagnosis and intervention have been the focus of extensive research in recent years with various clinical imaging techniques being applied for localization and tracking. The successful integration of well-designed m-bots with surface functionalization, remote actuation systems, and imaging techniques becomes the crucial step toward biomedical applications, especially for the in vivo uses. This review thus addresses four different aspects of biomedical m-bots: design/fabrication, functionalization, actuation, and localization. The biomedical applications of the m-bots in diagnosis, sensing, microsurgery, targeted drug/cell delivery, thrombus ablation, and wound healing are reviewed from these viewpoints. The developed biomedical m-bot systems are comprehensively compared and evaluated based on their characteristics. The current challenges and the directions of future research in this field are summarized.
    Keywords:  biomedical application; micro‐/nanorobots; real‐time imaging; swarm; targeted delivery
  16. ACS Nano. 2021 Feb 26.
      DNA nanotechnology has produced a wide range of self-assembled structures, offering unmatched possibilities in terms of structural design. Because of their programmable assembly and precise control of size, shape, and function, DNA particles can be used for numerous biological applications, including imaging, sensing, and drug delivery. While the biocompatibility, programmability, and ease of synthesis of nucleic acids have rapidly made them attractive building blocks, many challenges remain to be addressed before using them in biological conditions. Enzymatic hydrolysis, low cellular uptake, immune cell recognition and degradation, and unclear biodistribution profiles are yet to be solved. Rigorous methodologies are needed to study, understand, and control the fate of self-assembled DNA structures in physiological conditions. In this review, we describe the current challenges faced by the field as well as recent successes, highlighting the potential to solve biology problems or develop smart drug delivery tools. We then propose an outlook to drive the translation of DNA constructs toward preclinical design. We particularly believe that a detailed understanding of the fate of DNA nanostructures within living organisms, achieved through thorough characterization, is the next required step to reach clinical maturity.
    Keywords:  DNA nanotechnology; control experiments; drug delivery; in vivo; nanoparticles; nucleic acids; self-assembly; sensing; therapeutics