Project description:We develop a small molecule-inducible dimerization strategy of RBP of interest and adenosine deaminase domain to profile dynamic RBP-RNA interactions.
Project description:The immunosuppressive tumor microenvironment (TME) remains a major obstacle to tumor control and causes suboptimal responses to immune checkpoint blockade (ICB) therapy. Thus, developing feasible therapeutic strategies that trigger inflammatory responses in the TME could improve the ICB efficacy. Mitochondria play an essential role in inflammation regulation and tumor immunogenicity induction. Herein, we report the discovery and characterization of a new class of previously unappreciated small molecules that can recapitulate aqueous self-assembly behavior, specifically target cellular organelles (e.g., mitochondria), and invigorate tumor cell immunogenicity. Mechanistically, this nanoassembly platform dynamically rewires mitochondria, induces endoplasmic reticulum stress, and causes apoptosis/paraptosis-associated immunogenic cell death. After treatment, stressed and dying tumor cells can act as prophylactic or therapeutic cancer vaccines. In preclinical mouse models of cancers with intrinsic or acquired resistance to programmed death-1 (PD-1) blockade, the local administration of nanoassemblies inflames the immunologically silent TME and synergizes with ICB therapy, generating potent antitumor immunity. This chemically programmed small-molecule immune enhancer acts like no other reported cytotoxic therapeutics and offers a promising new strategy for synchronous and dynamic tailoring of innate immunity to achieve traceless cancer therapy and overcome immunosuppression in cancers.
Project description:Supramolecular prodrug self-assembly is a cost-effective and powerful approach for creating injectable anticancer nanoassemblies. Herein, we describe the self-assembly of small-molecule prodrug nanotherapeutics for tumor-restricted pharmacology that can be self-activated and independent of the exogenous stimuli. Covalent dimerization of the anticancer agent cabazitaxel via reactive oxygen species (ROS)- and esterase-activatable linkages produced the homodimeric prodrug diCTX, which was further coassembled with an ROS generator, dimeric dihydroartemisinin (diDHA). The coassembled nanoparticles were further refined in an amphiphilic matrix, making them suitable for in vivo administration. The ROS obtained from the coassembled diDHA synergized with intracellular esterase to activate the neighboring diCTX, which in turn induced potent cytotoxicity. In a preclinical orthotopic model of human osteosarcomas, nanoparticle administration exhibited durable antitumor efficacy. Furthermore, this smart, dual-responsive nanotherapeutic exhibited lower toxicity in animals than those of free drug combinations. We predict that this platform has great potential for further clinical translation.
Project description:The immunosuppressive tumor microenvironment (TME) remains a major obstacle to tumor control and causes suboptimal responses to immune checkpoint blockade (ICB) therapy. Thus, developing feasible therapeutic strategies that trigger inflammatory responses in the TME could improve the ICB efficacy. Mitochondria play an essential role in inflammation regulation and tumor immunogenicity induction. Herein, we report the discovery and characterization of a class of small molecules that can recapitulate aqueous self-assembly behavior, specifically target cellular organelles (e.g., mitochondria), and invigorate tumor cell immunogenicity. Mechanistically, this nanoassembly platform dynamically rewires mitochondria, induces endoplasmic reticulum stress, and causes apoptosis/paraptosis-associated immunogenic cell death. After treatment, stressed and dying tumor cells can act as prophylactic or therapeutic cancer vaccines. In preclinical mouse models of cancers with intrinsic or acquired resistance to PD-1 blockade, the local administration of nanoassemblies inflames the immunologically silent TME and synergizes with ICB therapy, generating potent antitumor immunity. This chemically programmed small-molecule immune enhancer acts distinctly from regular cytotoxic therapeutics and offers a promising strategy for synchronous and dynamic tailoring of innate immunity to achieve traceless cancer therapy and overcome immunosuppression in cancers.
Project description:The intracellular retention of nanotherapeutics is essential for their therapeutic activity. The immobilization of nanotherapeutics inside target cell types can regulate various cell behaviors. However, strategies for the intracellular immobilization of nanoparticles are limited. Herein, a cisplatin prodrug was synthesized and utilized as a glutathione (GSH)-activated linker to induce aggregation of the cisplatin prodrug/IR820/docetaxel nanoassembly. The nanoassembly has been reprogrammed with peptide-containing moieties for tumor-targeting and PD-1/PD-L1 blockade. The aggregation of the nanoassemblies is dependent on GSH concentration. Evaluations in vitro and in vivo revealed that GSH-induced intracellular aggregation of the nanoassemblies enhances therapeutic activity in primary tumors by enhancing the accumulation and prolonging the retention of the chemotherapeutics in the tumor site and inducing reactive oxygen species (ROS) generation and immunogenic cell death. Moreover, the nanoassemblies reinvigorate the immunocytes, especially the systemic immunocytes, and thereby alleviate pulmonary metastasis, even though the population of immunocytes in the primary tumor site is suppressed due to the enhanced accumulation of chemotherapeutics. This strategy provides a promising option for the intracellular immobilization of nanoparticles in vitro and in vivo.
Project description:Self-assembly of small molecules in water to form nanofibres, besides generating sophisticated biomaterials, promises a simple system inside cells for regulating cellular processes. But lack of a convenient approach for studying the self-assembly of small molecules inside cells hinders the development of such systems. Here we report a method to image enzyme-triggered self-assembly of small molecules inside live cells. After linking a fluorophore to a self-assembly motif to make a precursor, we confirmed by (31)P NMR and rheology that enzyme-triggered conversion of the precursor to a hydrogelator results in the formation of a hydrogel via self-assembly. The imaging contrast conferred by the nanofibres of the hydrogelators allowed the evaluation of intracellular self-assembly, the dynamics and the localization of the nanofibres of the hydrogelators in live cells. This approach explores supramolecular chemistry inside cells and may lead to new insights, processes or materials at the interface of chemistry and biology.
Project description:RNA-binding proteins play myriad roles in regulating RNAs and RNA-mediated functions. In bacteria, the RNA chaperone Hfq is an important post-transcriptional gene regulator. Using live-cell super-resolution imaging, we can distinguish Hfq binding to different sizes of cellular RNAs. We demonstrate that under normal growth conditions, Hfq exhibits widespread mRNA-binding activity, with the distal face of Hfq contributing mostly to the mRNA binding in vivo. In addition, sRNAs can either co-occupy Hfq with the mRNA as a ternary complex, or displace the mRNA from Hfq in a binding face-dependent manner, suggesting mechanisms through which sRNAs rapidly access Hfq to induce sRNA-mediated gene regulation. Finally, our data suggest that binding of Hfq to certain mRNAs through its distal face can recruit RNase E to promote turnover of these mRNAs in a sRNA-independent manner, and such regulatory function of Hfq can be decoyed by sRNA competitors that bind strongly at the distal face.
Project description:Regarded as the most promising technology for an early and precise detection of pancreatic cancer, a sensitive nanoprobe has been developed to enhance the accumulation of contrast agent at the tumor site. Hyaluronic acid (HA)-mediated multifunctional Fe3O4 nanoparticles (NPs) were used to target pancreatic cancer cells because on their cytomembrane they overexpress CD44, a receptor protein that has a high affinity to HA. The formation of HA-mediated multifunctional Fe3O4 nanoparticles began with the synthesis of polyethyleneimine (PEI·NH2) stabled Fe3O4 NPs by slight reduction. Subsequently, the formed Fe3O4@PEI·NH2 NPs were modified with fluorescein isothiocyanate (FITC), polyethylene glycol (mPEG-COOH) and HA in succession to form the multifunctional Fe3O4 NPs denoted as HA-Fe3O4 NPs. HA served as a targeting molecule to identify the surface antibody of CD44. As nanoparticles with a diameter of ca. 11.9 nm, the HA-Fe3O4 NPs exhibited very high r 2 relaxivity of 321.4 mM-1 s-1 and this has proved that HA-Fe3O4 NPs could be efficient T2-weighted magnetic resonance imaging (MRI) contrast agents. In a CCK8 cell proliferation assay of HA-Fe3O4 NPs, there was no toxic response for Fe concentrations up to 100 μg mL-1. Flow cytometry, confocal microscopy observation, and cell MRI results show that the HA-targeted groups had significantly higher cellular uptake than the nontargeted groups. This demonstrates that the HA-Fe3O4 NPs are uptaken by pancreatic cells via an HA-mediated targeting pathway. The HA-mediated active targeting strategy could be applied to other biomedical projects.
Project description:Like cellular proteins that form fibrillar nanostructures, small hydrogelator molecules self-assemble in water to generate molecular nanofibers. In contrast to the well-defined (dys)functions of endogenous protein filaments, the fate of intracellular assembly of small molecules remains largely unknown. Here we demonstrate the imaging of enzyme-triggered self-assembly of nonfluorescent small molecules by doping the molecular assemblies with a fluorescent hydrogelator. The cell fractionation experiments, fluorescent imaging, and electron microscopy indicate that the hydrogelators self-assemble and localize to the endoplasmic reticulum (ER) and are likely processed via the cellular secretory pathway (i.e., ER-Golgi-lysosomes/secretion). This work, as the first example of the use of correlative light and electron microscopy for probing the self-assembly of nonfluorescent small molecules inside live mammalian cells, not only establishes a general strategy to provide the spatiotemporal profile of the assemblies of small molecules inside cells but may lead to a new paradigm for regulating cellular functions based on the interactions between the assemblies of small molecules (e.g., molecular nanofibers) and subcellular organelles.