Peptide-Guided System with Programmable Subcellular Translocation for Targeted Therapy and Bypassing Multidrug Resistance

Advances in targeted tracking and detection of soluble amyloid-β aggregates as a biomarker of Alzheimer's disease

Misfolding and aggregation of amyloid-β (Aβ) peptides are key hallmarks of Alzheimer's disease (AD). With accumulating evidence suggesting that different Aβ species have varied neurotoxicity and implications in AD development, the discovery of affinity ligands and analytical approaches to selective distinguish, detect, and monitor Aβ becomes an active research area. Remarkable advances have been achieved, which not only promote our understanding of the biophysical chemistry of the protein aggregation during neurodegeneration, but also provide promising tools for early detection of the disease. In view of this, we summarize the recent progress in selective and sensitive approaches for tracking and detection of Aβ species. Specific attentions are given to soluble Aβ oligomers, due to their crucial roles in AD development and occurrence at early stages. The design principle, performance of targeting units, and their cooperative effects with signal reporters for Aβ analysis are discussed. The applications of the novel targeting probes and sensing systems for dynamic monitoring oligomerization, measuring Aβ in biosamples and in vivo imaging in brain are summarized. Finally, the perspective and challenges are discussed regarding the future development of Aβ-targeting analytical tools to explore the unknown field to contribute to the early diagnosis and treatment of AD.

Chemo-immunotherapy by dual-enzyme responsive peptide self-assembling abolish melanoma

Herein, we designed Comp. 1 to simultaneously respond to two enzymes: alkaline phosphatase and matrix metalloproteinase 2, which is commonly found in highly malignant cancer cell lines containing B16-F10 murine melanoma cells and CT26 murine colon carcinoma cells. We used the regional differences in the expression levels of dual-markers to accurately release immune molecule IND into tumor microenvironment for the activation of anti-tumor related immune effects, while in-situ self-assembly occurs. The dual-enzyme response process can further regulate the peptide precursors' self-assembly in the form of short rod-shaped nanofibers, enabling the delivery of the loaded chemotherapeutic drug HCPT into the cancer cells and further allowing the peptide assemblies to escape from lysosomes and return to cytoplasm in the form of tiny nanoparticles to induce apoptosis of cancer cells. This process does not occur in the single-positive breast cancer cell line MCF-7 or the normal hepatocytes cell line LO2, indicating the selectivity of the cancer cells exhibited using our strategy. In vivo studies revealed that Comp. 1 can effectively cooperate with chemotherapy to enhance the immunotherapy effect and induce immune responses associated with elevated pro-inflammatory cytokines in vivo to inhibit malignant tumors growth. Our dual-enzyme responsive chemo-immunotherapy strategy feasible in anti-tumor treatment, provides a new avenue for regulating peptide self-assembly to adapt to diverse tumor properties and may eventually be used for the development of novel multifunctional anti-tumor nanomedicines.

Molecularly Targeted Fluorescent Sensors for Visualizing and Tracking Cellular Senescence

Specific identification and monitoring of senescent cells are essential for the in-depth understanding and regulation of senescence-related life processes and diseases. Fluorescent sensors providing real-time and in situ information with spatiotemporal resolution are unparalleled tools and have contributed greatly to this field. This review focuses on the recent progress in fluorescent sensors for molecularly targeted imaging and real-time tracking of cellular senescence. The molecular design, sensing mechanisms, and biological activities of the sensors are discussed. The sensors are categorized by the types of markers and targeting ligands. Accordingly, their molecular recognition and fluorescent performance towards senescence biomarkers are summarized. Finally, the perspective and challenges in this field are discussed, which are expected to assist future design of next-generation sensors for monitoring cellular senescence.

Intra-Lysosomal Peptide Assembly for the High Selectivity Index against Cancer

Lysosomes remain powerful organelles and important targets for cancer therapy because cancer cell proliferation is greatly dependent on effective lysosomal function. Recent studies have shown that lysosomal membrane permeabilization induces cell death and is an effective way to treat cancer by bypassing the classical caspase-dependent apoptotic pathway. However, most lysosome-targeted anticancer drugs have very low selectivity for cancer cells. Here, we show intra-lysosomal self-assembly of a peptide amphiphile as a powerful technique to overcome this problem. We designed a peptide amphiphile that localizes in the cancer lysosome and undergoes cathepsin B enzyme-instructed supramolecular assembly. This localized assembly induces lysosomal swelling, membrane permeabilization, and damage to the lysosome, which eventually causes caspase-independent apoptotic death of cancer cells without conventional chemotherapeutic drugs. It has specific anticancer effects and is effective against drug-resistant cancers. Moreover, this peptide amphiphile exhibits high tumor targeting when attached to a tumor-targeting ligand and causes significant inhibition of tumor growth both in cancer and drug-resistant cancer xenograft models.

Peptide-derived coordination frameworks for biomimetic and selective separation

Peptide-derived metal-organic frameworks (PMOFs) have emerged as a class of biomimetic materials with attractive performances in analytical and bioanalytical chemistry. The incorporation of biomolecule peptides gives the frameworks conformational flexibility, guest adaptability, built-in chirality, and molecular recognition ability, which greatly accelerate the applications of PMOFs in enantiomeric separation, affinity separation, and the enrichment of bioactive species from complicated samples. This review focuses on the recent advances in the engineering and applications of PMOFs in selective separation. The unique biomimetic size-, enantio-, and affinity-selective performances for separation are discussed along with the chemical structures and functions of MOFs and peptides. Updates of the applications of PMOFs in adaptive separation of small molecules, chiral separation of drug molecules, and affinity isolation of bioactive species are summarized. Finally, the promising future and remaining challenges of PMOFs for selective separation of complex biosamples are discussed.

Self-assembly of Peptide dendrimers and their bio-applications in theranostics

Nanotechnology has brought revolutionized advances in disease diagnosis and therapy. Self-assembled peptide dendrimers own novel physicochemical properties through the synergistic effects of the polypeptide chain, dendrimer and nano-structure, exhibiting great potential in theranostic. This review provides comprehensive insights into various peptide dendrimers for self-assembly. Their nanosize, morphology and composition are presented to understand self-assembly behaviors precisely. We further introduce the emerging theranostic applications based on specific imaging and efficient delivery recently.

Localization of Organelle Proteins by Isotope Tagging: Current status and potential applications in drug discovery research

Spatial proteomics has provided important insights into the relationship between protein function and subcellular location. Localization of Organelle Proteins by Isotope Tagging (LOPIT) and its variants are proteome-wide techniques, not matched in scale by microscopy-based or proximity tagging-based techniques, allowing holistic mapping of protein subcellular location and re-localization events downstream of cellular perturbations. LOPIT can be a powerful and versatile tool in drug discovery for unlocking important information on disease pathophysiology, drug mechanism of action, and off-target toxicity screenings. Here, we discuss technical concepts of LOPIT with its potential applications in drug discovery and development research.

[Advances in the application of affinity separation for analyzing protein ubiquitination]

蛋白质泛素化是真核生物最普遍、最复杂的翻译后修饰方式之一,在细胞的信号转导、生长、发育、代谢等生命过程中发挥着重要作用。泛素化过程的失调则与神经退行性疾病、炎症反应、癌症等重大疾病的发生发展密切相关。分析和研究蛋白质泛素化的结构与功能,可望为认识生命、探索疾病调控内在规律和发现新的诊断策略提供重要信息。生命体系的高度复杂性,泛素化修饰位点、结构类型的多变和多样性,时空动态变化等特点给蛋白质泛素化分析研究带来了巨大的挑战。亲和分离以其高选择性成为泛素化蛋白质结构与功能研究的有力工具。免疫亲和分离法基于抗原-抗体相互作用,是最为经典的分离分析方法,已广泛应用于泛素化蛋白质或肽段的富集分离。源于天然泛素受体的泛素结合结构域(ubiquitin binding domains, UBDs)可与泛素或多聚泛素链相互作用。UBDs和基于此发展起来的串联泛素结合实体(tandem ubiquitin-binding entities, TUBEs)已成为蛋白质泛素化功能研究的热门识别分子。各种多肽类化合物的发展也为蛋白质泛素化的结构和功能解析提供新工具。此外,多种亲和识别配基的联合使用,在蛋白质泛素化修饰的高特异性、高灵敏度分析中展现了独特的优势,为认识生命体内的泛素化修饰提供了重要保障。该文对亲和分离方法在蛋白质泛素化修饰分析中的应用及进展进行了综述。

Engineering Peptide-Functionalized Biomimetic Nanointerfaces for Synergetic Capture of Circulating Tumor Cells in an EpCAM-Independent Manner

Broad-spectrum detection and long-term monitoring of circulating tumor cells (CTCs) remain challenging due to the extreme rarity, heterogeneity, and dynamic nature of CTCs. Herein, a dual-affinity nanostructured platform was developed for capturing different subpopulations of CTCs and monitoring CTCs during treatment. Stepwise assembly of fibrous scaffolds, a ligand-exchangeable spacer, and a lysosomal protein transmembrane 4 β (LAPTM4B)-targeting peptide creates biomimetic, stimuli-responsive, and multivalent-binding nanointerfaces, which enable harvest of CTCs directly from whole blood with high yield, purity, and viability. The stable overexpression of the target LAPTM4B protein in CTCs and the enhanced peptide-protein binding facilitate the capture of rare CTCs in patients at an early stage, detection of both epithelial-positive and nonepithelial CTCs, and tracking of therapeutic responses. The reversible release of CTCs allows downstream molecular analysis and identification of specific liver cancer genes. The consistency of the information with clinical diagnosis presents the prospect of this platform for early diagnosis, metastasis prediction, and prognosis assessment.

Nanomedicine Enables Drug-Potency Activation with Tumor Sensitivity and Hyperthermia Synergy in the Second Near-Infrared Biowindow

Disulfiram (DSF), a U.S. Food and Drug Administration (FDA)-approved drug for the treatment of chronic alcoholism, is also used as an antitumor drug in combination with Cu²⁺ ions. However, studies have shown that the endogenous Cu²⁺ dose in tumor tissues is still insufficient to form relatively high levels of a bis(N,N-diethyldithiocarbamate) copper(II) complex (denoted as Cu(DTC)₂) to selectively eradicate cancer cells. Here, DSF-loaded hollow copper sulfide nanoparticles (DSF@PEG-HCuSNPs) were designed to achieve tumor microenvironment (TME)-activated in situ formation of cytotoxic Cu(DTC)₂ for NIR-II-induced, photonic hyperthermia-enhanced, and DSF-initiated cancer chemotherapy. The acidic TME triggered the gradual degradation of DSF@PEG-HCuSNPs, promoting the rapid release of DSF and Cu²⁺ ions, causing the in situ formation of cytotoxic Cu(DTC)₂, to achieve efficient DSF-based chemotherapy. Additionally, DSF@PEG-HCuSNPs exhibited a notably high photothermal conversion efficiency of 23.8% at the second near-infrared (NIR-II) biowindow, thus significantly inducing photonic hyperthermia to eliminate cancer cells. Both in vitro and in vivo studies confirmed the effective photonic hyperthermia-induced chemotherapeutic efficacy of DSF by integrating the in situ formation of toxic Cu(DTC)₂ complexes and evident temperature elevation upon NIR-II laser irradiation. Thus, this study represents a distinctive paradigm of in situ Cu²⁺ chelation-initiated "nontoxicity-to-toxicity" transformation for photonic hyperthermia-augmented DSF-based cancer chemotherapy.

Metal-organic frameworks as advanced materials for sample preparation of bioactive peptides

Development of novel affinity materials and separation techniques is crucial for the progress of modern proteomics and peptidomics. Detection of peptides and proteins from complex matrices still remains a challenging task due to the highly complicated biological composition, low abundance of target molecules, and large dynamic range of proteins. As an emerging area of analytical science, metal-organic framework (MOF)-based separation of proteins and peptides is attracting growing interest. This minireview summarizes the recent advances in MOF-based affinity materials for the sample preparation of proteins and peptides. Some newly emerging MOF nanoreactors for the degradation of peptides and proteins are introduced. An update of MOF-based affinity materials for the isolation of glycopeptides, phosphopeptides and low-abundance endogenous peptides in the last two years is focused on. The separation mechanism is discussed along with the chemical structures of MOFs. Finally, the remaining challenges and future development of MOFs in analyzing peptides and proteins in complicated biological samples are discussed.

Peptide-Decorated Supramolecules for Subcellular Targeted Cancer Therapy: Recent Advances

Binding small molecules through non-covalent molecular forces affords supramolecules, such as hydrogen bonds, with electrostatic, π-π interactions, van der Waals forces, and hydrophobic effects. Due to their good biocompatibility, low immunogenicity, and biodegradability, supramolecules have been intensely studied as multifunctional drug delivery platforms in targeted cancer therapy. In consideration of the defective therapeutic efficacy induced by simply transporting the therapeutic agents into tumor tissues or cancer cells instead of subcellular organelles, research is progressing toward the development of subcellular targeted cancer therapy (STCT) strategies. STCT is one of the most recent developments in the field of cancer nanomedicine. It is defined as the specific transportation of therapeutic agents to the target organelles for cancer treatment, which makes therapeutic agents accumulate in the target organelles at higher concentrations than other subcellular compartments. Compared with tumor-targeted and cancer-cell-targeted therapies, STCT exhibits dramatically improved specificity and precision, diminished adverse effects, and enhanced capacity to reverse multidrug resistance (MDR). Over the past few decades, peptides have played increasingly essential roles in multi-types of tumor-targeted drug delivery systems. Moreover, peptide-mediated STCT is becoming an emerging approach for precision cancer therapy and has been used in various cancer treatments, such as photothermal therapy (PTT), photodynamic therapy (PDT), chemotherapy, gene therapy, and non-drug-loaded nanoassemblies. In this review, we will focus on recent innovations in the variety of peptides used in designing peptide-decorated supramolecules for cell-membrane-, mitochondria-, and nucleus-localized STCT.

Bifunctional Peptide-Conjugated Gold Nanoparticles for Precise and Efficient Nucleus-Targeting Bioimaging in Live Cells

Real-time in situ imaging of organelles is increasingly important in modern biomedical analysis and diseases diagnosis. To realize this goal, organelle-targeting nanoparticles as one of the most commonly used technologies in subcellular sensing and imaging has attracted a lot of interest. The biocompatibility, specificity, and binding efficiency are especially critical for efficient organelle-targeting bioimaging. Gold nanoparticles (AuNPs) fabricated with bifunctional peptides constructed with both Au-binding affinity and nucleus-targeting ability were designed and examined for efficient nucleus-targeting bioimaging. Such a design is expected to achieve an oriented assembling of peptides by the medium of the Au-binding peptides specifically assembled on the surface of AuNPs, with the nucleus-targeting end open for accessibility. The bifunctional peptides showed strong binding affinity toward AuNPs and led to a binding capability ∼1.5 times higher than that of the bare nucleus-targeting peptides, ensuring good surface coverage of the nanoparticles for enhanced nucleus-targeting ability. Such fabricated AuNPs demonstrated over 90% cell viability after incubation for 24 h with HepG2 cells, which were highly biocompatible. Precise and efficient bioimaging of the nucleus was achieved for HepG2 cells by using the fabricated AuNPs as observed with a confocal laser scanning microscope, a dark-field/fluorescence microscope, and a transmission electron microscope. The high surface coverage and oriented binding pattern appeared to be a promising strategy for construction of organelle-targeting agencies.

Targeted Transmembrane Delivery of Ca2+ via FA-Nanogel for Synergistically Enhanced Chemotherapy

Metal ion synergistically enhanced chemotherapy is a promising strategy for cancer treatment. However, targeting delivery of ions toward cancer cells remains challenging for decades. Herein, we developed a novel folic acid-nanogel (termed as FA-nanogel) with alkane chains as diffusion barriers for targeted transmembrane delivery of calcium ions into cancer cells. With the aid of hydrophobic diffusion barriers, the FA-nanogel showed a reduced and sustained speed for release of calcium ions, significantly prolonging the ion effect. Moreover, a pH-sensitive injectable hydrogel-loaded FA-nanogel and chemotherapeutic drug 5-fluorouracil (5-Fu) was synthesized for investigating the synergistic effect of nanogel on chemotherapy. Both in vitro and in vivo experiments confirmed that the intracellular calcium ions were continuously increased because of the targeted delivery ability and ion sustained release ability of the smart FA-nanogel, and the tumor growth was effectively inhibited by the ion synergistic chemotherapy. This study not only provides a powerful nanoplatform for sustained transmembrane delivery of ions into malignant cells but also creates better conditions for improving the therapeutic efficacy of chemotherapy.