3D hierarchic interfacial assembly of Au nanocage@Au along with IS-AgMNPs for simultaneous, ultrasensitive, reliable, and quantitative SERS detection of colorectal cancer related miRNAs.

Simultaneous, reliable, and ultra-sensitive analysis of promising miRNA biomarkers of colorectal cancer (CRC) in serum is critical for early diagnosis and prognosis of CRC. In this work, we proposed a novel 3D hierarchic assembly clusters-based SERS strategy with dual enrichment and enhancement designed for the ultrasensitive and quantitative analysis of two upregulated CRC-related miRNAs (miR-21 and miR-31). The biosensor contains the following: (1) SERS probe, Au nanocage@Au nanoparticles (AuNC@Au NPs) labeled with Raman reporters (RaRs). (2) magnetic capture unit, Ag-coated Fe3O4 magnetic nanoparticles (AgMNPs) modified with internal standard (IS). (3) signal amplify probes (SA probes) for the formation of hierarchic assembly clusters. Based on this sensing strategy, the intensity ratio IRaRs/IIS with Lg miRNAs presents a wide linear range (10 aM-100 pM) with a limit of detection of 3.46 aM for miR-21, 6.49 aM for miR-31, respectively. Moreover, the biosensor shows good specificity and anti-interference ability, and the reliability and repeatability of the strategy were then verified by practical detection of clinical serum. Finally, the biosensor can distinguish CRC cancer subjects from normal ones and guide the distinct tumor, lymph node, and metastasis (TNM) stages. Overall, benefiting from the face-to-face coupling of hierarchic assembly clusters, rapid magnetic enrichment and IS signal calibration of AgMNPs, the established biosensor achieves ultra-sensitive and simultaneous detection of dual miRNAs and opens potential avenues for prediction and staging of CRC.

Novel Covalent Probe Selectively Targeting Glutathione Peroxidase 4 In Vivo: Potential Applications in Pancreatic Cancer Therapy.

Glutathione peroxidase 4 (GPX4) emerges as a promising target for the treatment of therapy-resistant cancer through ferroptosis. Thus, there is a broad interest in the development of GPX4 inhibitors. However, a majority of reported GPX4 inhibitors utilize chloroacetamide as a reactive electrophilic warhead, and the selectivity and pharmacokinetic properties still need to be improved. Herein, we developed a compound library based on a novel electrophilic warhead, the sulfonyl ynamide, and executed phenotypic screening against pancreatic cancer cell lines. Notably, one compound A16 exhibiting potent cell toxicity was identified. Further chemical proteomics investigations have demonstrated that A16 specifically targets GPX4 under both in situ and in vivo conditions, inducing ferroptosis. Importantly, A16 exhibited superior selectivity and potency compared to reported GPX4 inhibitors, ML210 and ML162. This provides the structural diversity of tool probes for unraveling the fundamental biology of GPX4 and exploring the therapeutic potential of pancreatic cancer via ferroptosis induction.

In Situ Tyrosinase Monitoring by Wearable Microneedle Patch toward Clinical Melanoma Screening.

Despite the potential indicating role of tyrosinase (TYR) in cutaneous melanoma, how to capture the real changes of TYR in suspicious skin remains a major challenge. Unlike the traditional human serum test, this study reports a sensing platform that incorporates a wearable microneedle (MN) patch and trimetallic Au@Ag-Pt nanoparticles (NPs) for surface-enhanced Raman scattering (SERS) and colorimetric dual-mode detecting TYR in human skin in situ toward potential melanoma screening. In the presence of TYR, catechol immobilized on MN is preferentially oxidized to benzoquinone, which competitively impedes the interaction of MN and Au@Ag-Pt NPs, triggering the SERS-colorimetric signal reciprocal switch. Using a B16F10 mouse melanoma model, our platform is capable of noninvasively piercing the skin surface and detecting TYR levels before and during anti-PD-1 antibody treatment, which would be highly informative for prognostic judgment and illness monitoring of melanoma. Through in situ sensing for capturing the metabolic changes of TYR in advance, this platform was successfully applied to discriminate the melanoma subjects from skin moles and normal ones (p < 0.001), as well as screen potential melanoma from lactate dehydrogenase (LDH)-negative patients. Melanoma growth and prognosis can still be monitored through recording the continuous change of TYR levels. More importantly, the well-defined flexible and stretchable characteristics of the MN patch allow robustly adhering to the skin without inducing chemical or physical irritation. We believe this platform integrating MN-based in situ sensing, TYR responsiveness, and SERS/colorimetric dual-readout strategy will have high clinical importance in early diagnosis and monitoring of cutaneous melanoma.

Novel Coumarin Derivatives Inhibit the Quorum Sensing System and Iron Homeostasis as Antibacterial Synergists against Pseudomonas aeruginosa.

Pseudomonas aeruginosa (P. aeruginosa) is well-known to cause biofilm-associated drug resistance and infections that often lead to treatment failure. Herein, we reported a dual-acting antibiofilm strategy by inhibiting both the bacterial quorum sensing system and the iron uptake system. A series of coumarin derivatives were synthesized and evaluated, and compound 4t was identified as the most effective biofilm inhibitor (IC50 = 3.6 µM). Further mechanistic studies have confirmed that 4t not only inhibits the QS systems but also competes strongly with pyoverdine as an iron chelator, causing an iron deficiency in P. aeruginosa. Additionally, 4t significantly improved the synergistic antibacterial effects of ciprofloxacin and tobramycin by more than 200-1000-fold compared to the single-dose antibiotic treatments. Therefore, our study has shown that 4t is a potentially novel antibacterial synergist candidate to treat bacterial infections.

Erratum: Author correction to 'Real-time SERS monitoring anticancer drug release along with SERS/MR imaging for pH-sensitive chemo-phototherapy' [Acta Pharm Sin B 13 (2023) 1303-1317].

[This corrects the article DOI: 10.1016/j.apsb.2022.08.024.].

New abietane and tigliane diterpenoids from the roots of Euphorbia fischeriana and their cytotoxic activities.

Three new abietane and two new tigliane diterpenoids were isolated from the roots Euphorbia fischeriana. Their structures were elucidated by spectroscopic methods and quantum chemical calculation. Compounds 4 and 5 exhibited the inhibitory activities against human cancer cells HeLa and HepG2, with IC50 ranging from 3.54 to 11.45 µM.

Antiviral activities of Artemisia vulgaris L. extract against herpes simplex virus.

BACKGROUND: Artemisia vulgaris L. is often used as a traditional Chinese medicine with the same origin of medicine and food. Its active ingredient in leaves have multiple biological functions such as anti-inflammatory, antibacterial and insecticidal, anti-tumor, antioxidant and immune regulation, etc. It is confirmed that folium Artemisiae argyi has obvious anti-HBV activity, however, its antiviral activity and mechanism against herpesvirus or other viruses are not clear. Hence, we aimed to screen the crude extracts (Fr.8.3) isolated and extracted from folium A. argyi to explore the anti-herpesvirus activity and mechanism. METHODS: The antiherpes virus activity of Fr.8.3 was mainly characterized by cytopathic effects, real-time PCR detection of viral gene replication and expression levels, western blotting, viral titer determination and plaque reduction experiments. The main components of Fr.8.3 were identified by using LC-MS, and selected protein targets of these components were investigated through molecular docking. RESULTS: We collected and isolated a variety of A. vulgaris L. samples from Tangyin County, Henan Province and then screened the A. vulgaris L. leaf extracts for anti-HSV-1 activity. The results of the plaque reduction test showed that the crude extract of A. vulgaris L.-Fr.8.3 had anti-HSV-1 activity, and we further verified the anti-HSV-1 activity of Fr.8.3 at the DNA, RNA and protein levels. Moreover, we found that Fr.8.3 also had a broad spectrum of antiviral activity. Finally, we explored its anti-HSV-1 mechanism, and the results showed that Fr.8.3 exerted an anti-HSV-1 effect by acting directly on the virus itself. Then, the extracts were screened on HSV-1 surface glycoproteins and host cell surface receptors for potential binding ability by molecular docking, which further verified the phenotypic results. LC-MS analysis showed that 1 and 2 were the two main components of the extracts. Docking analysis suggested that compounds from extract 1 might similarly cover the binding domain between the virus and the host cells, thus interfering with virus adhesion to cell receptors, which provides new ideas and insights for clinical drug development for herpes simplex virus type 1. CONCLUSION: We found that Fr.8.3 has anti-herpesvirus and anti-rotavirus effects. The main 12 components in Fr.8.3 were analyzed by LC-MS, and the protein targets were finally predicted through molecular docking, which showed that alkaloids may play a major role in antiviral activity.

Real-time SERS monitoring anticancer drug release along with SERS/MR imaging for pH-sensitive chemo-phototherapy.

In situ and real-time monitoring of responsive drug release is critical for the assessment of pharmacodynamics in chemotherapy. In this study, a novel pH-responsive nanosystem is proposed for real-time monitoring of drug release and chemo-phototherapy by surface-enhanced Raman spectroscopy (SERS). The Fe3O4@Au@Ag nanoparticles (NPs) deposited graphene oxide (GO) nanocomposites with a high SERS activity and stability are synthesized and labeled with a Raman reporter 4-mercaptophenylboronic acid (4-MPBA) to form SERS probes (GO-Fe3O4@Au@Ag-MPBA). Furthermore, doxorubicin (DOX) is attached to SERS probes through a pH-responsive linker boronic ester (GO-Fe3O4@Au@Ag-MPBA-DOX), accompanying the 4-MPBA signal change in SERS. After the entry into tumor, the breakage of boronic ester in the acidic environment gives rise to the release of DOX and the recovery of 4-MPBA SERS signal. Thus, the DOX dynamic release can be monitored by the real-time changes of 4-MPBA SERS spectra. Additionally, the strong T2 magnetic resonance (MR) signal and NIR photothermal transduction efficiency of the nanocomposites make it available for MR imaging and photothermal therapy (PTT). Altogether, this GO-Fe3O4@Au@Ag-MPBA-DOX can simultaneously fulfill the synergistic combination of cancer cell targeting, pH-sensitive drug release, SERS-traceable detection and MR imaging, endowing it great potential for SERS/MR imaging-guided efficient chemo-phototherapy on cancer treatment.

Selenium-Electrocatalytic Cyclization of 2-Vinylanilides towards Indoles of Peptide Labeling.

A novel selenium-electrocatalytic intramolecular cyclization of 2-vinylanilides for synthesis of functionalized indoles and azaindoles has been developed. In contrast to the previous synthetic methods, this sustainable protocol enabled unparalleled broad substrates scope for viable indoles with highly functional and sensitive groups by employing recyclable selenium catalyst, under mild, metal- and external-oxidant-free conditions. The approach can be used to the late-stage modification of complex bioactive molecular system, thereby setting the stage for versatile syntheses of decorated indoles with peptide labeling. A plausible catalytic pathway was proposed.

Ynamide Electrophile for the Profiling of Ligandable Carboxyl Residues in Live Cells and the Development of New Covalent Inhibitors.

Covalent inhibitors with an electrophilic warhead have received considerable attention due to their remarkable pharmacological properties. However, the electrophilic warhead in covalent drugs is often an α, ß-unsaturated amide, and the targets are mainly cysteine or lysine residues. Thus, the development of novel electrophiles that can target other amino acids is highly desirable. Ynamide, a useful and versatile building block, is commonly employed in the construction of various compounds in organic synthesis. The performance of this functional group in a proteome-wide environment has been studied here for the first time, and it has been shown that it can efficiently modify carboxyl residues in situ and in vitro. Upon incorporation of this ynamide warhead into the pharmacophores of kinase inhibitors, the resulting compound showed moderate inhibition against the EGFR L858R mutant but not against EGFR WT. This novel electrophilic group can be used in the development of new types of covalent inhibitors.

Rationally engineering santalene synthase to readjust the component ratio of sandalwood oil.

Plant essential oils (PEOs) are widely used in cosmetic and nutraceutical industries. The component ratios of PEOs determine their qualities. Controlling the component ratios is challenging in construction of PEO biotechnological platforms. Here, we explore the catalytic reaction pathways of both product-promiscuous and product-specific santalene synthases (i.e., SaSSy and SanSyn) by multiscale simulations. F441 of SanSyn is found as a key residue restricting the conformational dynamics of the intermediates, and thereby the direct deprotonation by the general base T298 dominantly produce α-santalene. The subsequent mutagenesis of this plastic residue leads to generation of a mutant enzyme SanSynF441V which can produce both α- and ß-santalenes. Through metabolic engineering efforts, the santalene/santalol titer reaches 704.2 mg/L and the component ratio well matches the ISO 3518:2002 standard. This study represents a paradigm of constructing biotechnological platforms of PEOs with desirable component ratios by the combination of metabolic and enzymatic engineering.

PPAR-γ integrates obesity and adipocyte clock through epigenetic regulation of Bmal1.

While growing evidence suggests that circadian clock and obesity are intertwined, the underlying mechanism is poorly understood. Here, we investigate how circadian clock is linked to obesity. Methods: Metabolomics profiling of WAT (white adipose tissue) samples was performed to identify the metabolites altered in obese model. mRNA levels were analyzed by qPCR assays. Proteins were detected by immunoblotting, immunofluorescence and ELISA. ChIP and luciferase reporter assays were used to investigate epigenetic and transcriptional regulation. Results: Obesity causes perturbance of circadian clock in WAT in mice and humans, particularly, BMAL1 is markedly reduced. Metabolomic analysis reveals reduced glutamine and methionine in obese WAT. Glutamine metabolism contributes to production of acetyl-CoA, whereas methionine metabolism generates S-adenosyl methionine (SAM). Acetyl-CoA and SAM are the substrates for histone acetylation and methylation, respectively. Reduced glutamine and methionine in obese WAT are associated with decreased H3K27ac and H3K4me3 at Bmal1 promoter. Consistently, glutamine or methionine administration in vitro and in vivo increases H3K27ac or H3K4me3, promoting Bmal1 transcription and expression. A screen of transport and metabolic genes identifies downregulation of the uptake transporter SLC1A5 as a cause of reduced glutamine or methionine in obese WAT. Moreover, we observe impaired expression of PPAR-γ in obese WAT. PPAR-γ trans-activates Slc1a5 via direct binding to a response element in promoter. Conclusion: Impaired PPAR-γ in obesity provokes downregulation of SLC1A5 and reductions in adipocyte uptake of glutamine and methionine (two epigenetic modulators), leading to disruption of Bmal1. Therefore, PPAR-γ integrates obesity and adipocyte clock, promoting a vicious cycle between circadian disruption and obesity development.

Secondary-structure switch regulates the substrate binding of a YopJ family acetyltransferase.

The Yersinia outer protein J (YopJ) family effectors are widely deployed through the type III secretion system by both plant and animal pathogens. As non-canonical acetyltransferases, the enzymatic activities of YopJ family effectors are allosterically activated by the eukaryote-specific ligand inositol hexaphosphate (InsP6). However, the underpinning molecular mechanism remains undefined. Here we present the crystal structure of apo-PopP2, a YopJ family member secreted by the plant pathogen Ralstonia solanacearum. Structural comparison of apo-PopP2 with the InsP6-bound PopP2 reveals a substantial conformational readjustment centered in the substrate-binding site. Combining biochemical and computational analyses, we further identify a mechanism by which the association of InsP6 with PopP2 induces an α-helix-to-ß-strand transition in the catalytic core, resulting in stabilization of the substrate recognition helix in the target protein binding site. Together, our study uncovers the molecular basis governing InsP6-mediated allosteric regulation of YopJ family acetyltransferases and further expands the paradigm of fold-switching proteins.

Novel Electrophilic Warhead Targeting a Triple-Negative Breast Cancer Driver in Live Cells Revealed by "Inverse Drug Discovery".

The "inverse drug discovery" strategy is a potent means of exploring the cellular targets of latent electrophiles not typically used in medicinal chemistry. Cyclopropenone, a powerful electrophile, is generally used in bio-orthogonal reactions mediated by triarylphosphine or in photo-triggered cycloaddition reactions. Here, we have studied, for the first time, the proteome reactivity of cyclopropenones in live cells and discovered that the cyclopropenone warhead can specifically and efficiently modify a triple-negative breast cancer driver, glutathione S-transferase pi-1 (GSTP1), by covalently binding at the catalytic active site. Further structure optimization and signaling pathway validation have led to the discovery of potent inhibitors of GSTP1.

Bioresponsive nanomedicines based on dynamic covalent bonds.

Trends in the development of modern medicine necessitate the efficient delivery of therapeutics to achieve the desired treatment outcomes through precise spatiotemporal accumulation of therapeutics at the disease site. Bioresponsive nanomedicine is a promising platform for this purpose. Dynamic covalent bonds (DCBs) have attracted much attention in studies of the fabrication of bioresponsive nanomedicines with an abundance of combinations of therapeutic modules and carrier function units. DCB-based nanomedicines could be designed to maintain biological friendly synthesis and site-specific release for optimal therapeutic effects, allowing the complex to retain an integrated structure before accumulating at the disease site, but disassembling into individual active components without compromising function in the targeted organs or tissues. In this review, we focus on responsive nanomedicines containing dynamic chemical bonds that can be cleaved by various specific stimuli, enabling achievement of targeted drug release for optimal therapy in various diseases.

Ultrasensitive and Simultaneous SERS Detection of Multiplex MicroRNA Using Fractal Gold Nanotags for Early Diagnosis and Prognosis of Hepatocellular Carcinoma.

Sensitive and simultaneous detection of multiple cancer-related biomarkers in serum is essential for diagnosis, therapy, prognosis, and staging of cancer. Herein, we proposed a magnetically assisted sandwich-type surface-enhanced Raman scattering (SERS)-based biosensor for ultrasensitive and multiplex detection of three hepatocellular carcinoma-related microRNA (miRNA) biomarkers. The biosensor consists of an SERS tag (probe DNA-conjugated DNA-engineered fractal gold nanoparticles, F-AuNPs) and a magnetic capture substrate (capture DNA-conjugated Ag-coated magnetic nanoparticles, AgMNPs). The proposed strategy achieved simultaneous and sensitive detection of three miRNAs (miRNA-122, miRNA-223, and miRNA-21), and the limits of detection of the three miRNAs in human serum are 349 aM for miRNA-122, 374 aM for miRNA-223, and 311 aM for miRNA-21. High selectivity and accuracy of the SERS biosensor were proved by practical analysis in human serum. Moreover, the biosensor exhibited good practicability in multiplex detection of three miRNAs in 92 clinical sera from AFP-negative patients, patients before and after hepatectomy, recurred and relapse-free patients after hepatectomy, and hepatocellular carcinoma patients at distinct Barcelona clinic liver cancer stages. The experiment results demonstrate that our SERS-based assay is a promising candidate in clinical application and exhibited potential for the prediction, diagnosis, monitoring, and staging of cancers.

Sizes and ligands tuned gold nanocluster acting as a new type of monoamine oxidase B inhibitor.

Monoamine oxidase inhibitors (MAOIs) are a class of drugs that can be used in the treatment of Parkinson's disease, clinical depression, and anxiety by targeting monoamine oxidase B (MAO). However, the side effects of MAOIs drive the requirement of a new framework of enzyme inhibitors development. In this context, a new type of MAOI has been built on the framework of gold nanoclusters (AuNCs), realizing the transformation from no function of small molecules to MAOI function of ligand-modified AuNCs. The MAOI activity of fabricated AuNCs can be achieved by size control and specific ligands modification. In this work, AuNCs modified with cysteamine or 4-aminothiophenol, about 1-3 nm in size, were found to have MAOI activity (MAOI-like AuNCs) and their characterization has been extensively described. Meanwhile, the possible mechanism behind this MAOI activity has been explored and it is believed that the proper size of AuNCs with ligands containing amino groups can bind tightly with the entrance to active sites of MAO, blocking the enzyme interacting with its substrates, thereby realizing the function of MAOI. Last, the antimicrobial activity and the performance of the MAOI-like AuNCs in the human blood sample were explored and suggested that MAOI-like AuNCs do not possess strong antimicrobial activity and have no visualized side effect on blood cells, although the by-product peroxide of MAO reaction may reshape the white blood cells. The research in this work may shed some light on the development of a new type of enzyme inhibitor based on the framework of nanomaterials.

Click-Reaction-Triggered SERS Signals for Specific Detection of Monoamine Oxidase B Activity.

Human monoamine oxidases (MAOs) play important roles in maintaining the homeostasis of biogenic amines. One of its isoforms, monoamine oxidase B (MAOB), is thought to be involved in several neurodegenerative diseases, which make the selective detection of MAOB activity essential. In this work, a novel surface-enhanced Raman scattering (SERS) sensor was fabricated and the MAOB activity was specifically determined by detecting the SERS signals of an enzyme-catalyzed reaction product via an amine-aldehyde click reaction. This process was simply achieved by coating core-shell gold-silver nanoparticles (Au@Ag NPs) on 3-aminopropyl aminopropyl triethoxysilane (APTES)-modified glass, and then, a monolayer of cysteamine (CA) was attached to the nanoparticle surface as a linker through Ag-S bonds. Using phenethylamine (PA) as a specific substrate of MAOB, the enzyme product phenylacetaldehyde (PAA) will produce significant Raman signals via the amine-aldehyde click reaction with CA, while other molecules, such as MAOB and PA, have no signal output because they cannot form close interaction with nanoparticles due to the existence of a CA layer. This sensor was further used for the specific determination of MAOB activity in clinical blood samples and the MAOB inhibitor assessment successfully. Meanwhile, by changing the click reaction types and taking advantage of the SERS fingerprint peaks for the specific click reaction products, this strategy offers huge potential to detect multiple enzyme activities simultaneously and can be used for new click reaction screening, enzyme-related disease diagnosis, drug screening, and clinical diagnosis.

Diterpenoid Lactones with Anti-Inflammatory Effects from the Aerial Parts of Andrographis paniculata.

Andrographis paniculata (AP) has been widely used in China for centuries to treat various diseases, and especially to treat inflammation. Diterpenoid lactones are the main anti-inflammatory components of AP. However, systematic chemical composition and biological activities, as well as key pharmacophores, of these diterpenoid lactones from AP have not yet been clearly understood. In this study, 17 diterpenoid lactones, including 2 new compounds, were identified by spectroscopic methods, and most of them attenuated the generation of TNF-α and IL-6 in LPS-induced RAW 274.7 cells examined by ELISA. Pharmacophores of diterpenoid lactones responsible for the anti-inflammatory activities were revealed based on the quantitative structure-activity relationship (QSAR) models. Moreover, new compounds (AP-1 and AP-4) exerted anti-inflammatory activity in LPS microinjection-induced zebrafish, which might be correlated with the inhibition of the translocation of NF-κB p65 from cytoplasm to nucleus. Our study provides guidelines for future structure modification and rational drug design of diterpenoid lactones with anti-inflammatory properties in medical chemistry.

An Overview of HDAC Inhibitors and their Synthetic Routes.

Epigenetics play a key role in the origin, development and metastasis of cancer. Epigenetic processes include DNA methylation, histone acetylation, histone methylation, and histone phosphorylation, among which, histone acetylation is the most common one that plays important roles in the regulation of normal cellular processes, and is controlled by histone deacetylases (HDACs) and histone acetyltransferases (HATs). HDACs are involved in the regulation of many key cellular processes, such as DNA damage repair, cell cycle control, autophagy, metabolism, senescence and chaperone function, and can lead to oncogene activation. As a result, HDACs are considered to be an excellent target for anti-cancer therapeutics like histone deacetylase inhibitors (HDACi) which have attracted much attention in the last decade. A wide-ranging knowledge of the role of HDACs in tumorigenesis, and of the action of HDACi, has been achieved. The primary purpose of this paper is to summarize recent HDAC inhibitors and the synthetic routes as well as to discuss the direction for the future development of new HDAC inhibitors.