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Developing broad-spectrum influenza vaccines is crucial for influenza control and potential pandemic preparedness. Here, we reported a novel vaccine design utilizing circular RNA (circRNA) as a delivery platform for multi-subtype neuraminidases (NA) (influenza A N1, N2, and influenza B Victoria lineage NA) immunogens. Individual NA circRNA lipid nanoparticles (LNP) elicited robust NA-specific antibody responses with neuraminidase inhibition activity (NAI), preventing the virus from egressing and infecting neighboring cells. Additionally, the administration of circRNA LNP induced cellular immunity in mice. To achieve a universal influenza vaccine, we combined all three subtypes of NA circRNA-LNPs to generate a trivalent circRNA vaccine. The trivalent vaccine elicited a balanced antibody response against all three NA subtypes and a Th1-biased immune response in mice. Moreover, it protected mice against the lethal challenge of matched and mismatched H1N1, H3N2, and influenza B viruses, encompassing circulating and ancestral influenza virus strains. This study highlights the potential of delivering multiple NA antigens through circRNA-LNPs as a promising strategy for effectively developing a universal influenza vaccine against diverse influenza viruses.

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OBJECTIVE: This study aimed to comprehensively analyze the clinical characteristics and treatment status of Chinese small cell carcinoma of the ovary hypercalcemic type (SCCOHT) patients, providing insights into this unique population and comparing findings with international literature. METHODS: Through a meta-analysis, we collected data from published case reports and records from the Obstetrics & Gynecology Hospital of Fudan University. Demographic information, clinical presentations, tumor attributes, treatment modalities, and survival outcomes were extracted and examined alongside relevant global studies. RESULTS: The analysis encompassed 80 Chinese SCCOHT patients, of which 62 from 33 previously reported literatures, and the other 18 were from Obstetrics & Gynecology Hospital of Fudan University. In 62 cases with stage information, A total of 25 tumors were International Federation of Gynecology and Obstetrics stage I, 3 were stage II, 19 were stage III, and 15 were stage IV. Most patients received surgery and chemotherapy, but regimens were varied. Median follow-up was 10 months (range=4-120). Elevated carbohydrate antigen 125 and serum calcium levels were consistent findings. Recurrence rates were notable, especially among stage I patients. Platinum-based chemotherapy, paclitaxel and carboplatin (n=11, 13.4%), constituted common treatment regimens. CONCLUSION: This study observed demographic and clinical similarities with international datasets. And the findings emphasize the urgency for innovative therapeutic approaches to improve outcomes in SCCOHT patients. Continued research efforts are essential to enhance the knowledge surrounding this rare malignancy and to optimize its clinical management.

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Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare but highly aggressive ovarian malignant neoplasm lacking a unified clinical management process. Most patients are diagnosed at an advanced stage and have an extremely poor prognosis with an overall probability of survival less than 10 %. Here, we describe the case of a patient with advanced SCCOHT achieved a survival of over 5 years after receiving multiple cycles of immunotherapy combined with anti-angiogenic therapy or CDK4/6 inhibitors. At the same time, we also summarized the case reports and clinical trials of immunotherapy in SCCOHT.

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Nanobodies have emerged as promising tools in biomedicine due to their single-chain structure and inherent stability. They generally have convex paratopes, which potentially prefer different epitope sites in an antigen compared to traditional antibodies. In this study, a synthetic phage display nanobody library was constructed and used to identify nanobodies targeting a tumor-associated antigen, the human B7-H3 protein. Combining next-generation sequencing and single-clone validation, two nanobodies were identified to specifically bind B7-H3 with medium nanomolar affinities. Further characterization revealed that these two clones targeted a different epitope compared to known B7-H3-specific antibodies, which have been explored in clinical trials. Furthermore, one of the clones, dubbed as A6, exhibited potent antibody-dependent cell-mediated cytotoxicity (ADCC) against a colorectal cancer cell line with an EC50 of 0.67 nM, upon conversion to an Fc-enhanced IgG format. These findings underscore a cost-effective strategy that bypasses the lengthy immunization process, offering potential rapid access to nanobodies targeting unexplored antigenic sites.

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The objective of this study was to explore the potential of Antarctic krill-derived peptides as α-glucosidase inhibitors for the treatment of type 2 diabetes. The enzymolysis conditions of α-glucosidase inhibitory peptides were optimized by response surface methodology (RSM), a statistical method that efficiently determines optimal conditions with a limited number of experiments. Gel chromatography and LC-MS/MS techniques were utilized to determine the molecular weight (Mw) distribution and sequences of the hydrolysates. The identification and analysis of the mechanism behind α-glucosidase inhibitory peptides were conducted through conventional and computer-assisted techniques. The binding affinities between peptides and α-glucosidase were further validated using BLI (biolayer interferometry) assay. The results revealed that hydrolysates generated by neutrase exhibited the highest α-glucosidase inhibition rate. Optimal conditions for hydrolysis were determined to be an enzyme concentration of 6 × 103 U/g, hydrolysis time of 5.4 h, and hydrolysis temperature of 45 °C. Four peptides (LPFQR, PSFD, PSFDF, VPFPR) with strong binding affinities to the active site of α-glucosidase, primarily through hydrogen bonding and hydrophobic interactions. This study highlights the prospective utility of Antarctic krill-derived peptides in curtailing α-glucosidase activity, offering a theoretical foundation for the development of novel α-glucosidase inhibitors and related functional foods to enhance diabetes management.

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Human DNA topoisomerase 1 (Top1) is a crucial enzyme responsible for alleviating torsional stress on DNA during transcription and replication, thereby maintaining genome stability. Previous researches had found that non-working Top1 interacted extensively with chromosomal DNA in human cells. However, the reason for its retention on chromosomal DNA remained unclear. In this study, we discovered a close association between Top1 and chromosomal DNA, specifically linked to the presence of G-quadruplex (G4) structures. G4 structures, formed during transcription, trap Top1 and hinder its ability to relax neighboring DNAs. Disruption of the Top1-G4 interaction using G4 ligand relieved the inhibitory effect of G4 on Top1 activity, resulting in a further reduction of R-loop levels in cells. Additionally, the activation of Top1 through the use of a G4 ligand enhanced the toxicity of Top1 inhibitors towards cancer cells. Our study uncovers a negative regulation mechanism of human Top1 and highlights a novel pathway for activating Top1.

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The Hippo pathway controls developmental, homeostatic and regenerative tissue growth, and is frequently dysregulated in various diseases. Although this pathway can be activated by innate immune/inflammatory stimuli, the underlying mechanism is not fully understood. Here, we identify a conserved signaling cascade that leads to Hippo pathway activation by innate immune/inflammatory signals. We show that Tak1, a key kinase in innate immune/inflammatory signaling, activates the Hippo pathway by inducing the lysosomal degradation of Cka, an essential subunit of the STRIPAK PP2A complex that suppresses Hippo signaling. Suppression of STRIPAK results in the activation of Hippo pathway through Tao-Hpo signaling. We further show that Tak1-mediated Hippo signaling is involved in processes ranging from cell death to phagocytosis and innate immune memory. Our findings thus reveal a molecular connection between innate immune/inflammatory signaling and the evolutionally conserved Hippo pathway, thus contributing to our understanding of infectious, inflammatory and malignant diseases.

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The effective modulation of pancreatic lipase and cholesterol esterase activities proves critical in maintaining circulatory triglycerides and cholesterol levels within physiological boundaries. In this study, peptides derived from KPHs-AL, produced through the enzymatic hydrolysis of skipjack tuna dark muscle using alkaline protease, have a specific inhibitory effect on pancreatic lipase and cholesterol esterase. It is hypothesized that these peptides target and modulate the activities of enzymes by inducing conformational changes within their binding pockets, potentially impacting the catalytic functions of both pancreatic lipase and cholesterol esterase. Results revealed these peptides including AINDPFIDL, FLGM, GLLF and WGPL, were found to nestle into the binding site groove of pancreatic lipase and cholesterol esterase. Among these, GLLF stood out, demonstrating potent inhibition with IC50 values of 0.1891 mg/mL and 0.2534 mg/mL for pancreatic lipase and cholesterol esterase, respectively. The kinetics studies suggested that GLLF competed effectively with substrates for the enzyme active sites. Spectroscopic analyses, including ultraviolet-visible, fluorescence quenching, and circular dichroism, indicated that GLLF binding induced conformational changes within the enzymes, likely through hydrogen bond formation and hydrophobic interactions, thereby increasing structural flexibility. Molecular docking and molecular dynamics simulations supported these findings, showing GLLF's stable interaction with vital active site residues. These findings position GLLF as a potent inhibitor of key digestive enzymes, offering insights into its role in regulating lipid metabolism and highlighting its potential as functional ingredient.

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Background: Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST) is a standardized depression prevention program for adolescents conducted in campus settings. The purpose of this review is to examine the randomized controlled trials of IPT-AST for the prevention of adolescent depression in the past 20 years. Methods: A systematic search of relevant electronic databases (PubMed, WOS, Embase, PsycINFO, the Cochrane Library, CNKI and WANFANG DATA) and study reference lists was conducted. Any study investigating the effectiveness of IPT-AST in 12- to 20-year-olds with depressive symptoms was eligible. Synthesis was via narrative summary and meta-analysis. Results: A total of 6 studies met the inclusion criteria. Meta-analysis results showed a remarkable improvement in patients' depressive symptoms after IPT-AST intervention (WMD = -5.05, 95% CI = -8.11 to -1.98, p < 0.05, I2 = 77%). Six month follow-up data showed that the intervention outcomes of IPT-AST remained significant (WMD = -3.09, 95% CI: -5.23 to -0.94, p < 0.05, I2 = 57%). Conclusion: This meta-analysis showed that IPT-AST was effective in adolescents with depressive symptoms at post-prevention and at 6-month follow-up. However, these conclusions are cautious, as they are based on a small number of studies and the presence of author duplication. Future studies should use multi-center, large-sample randomized controlled trials to evaluate the efficacy of IPT-AST for preventing depression in adolescents. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023393047.

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Small cell carcinoma of the ovary hypercalcemic type (SCCOHT) is a rare and aggressive malignancy that poses a significant clinical challenge due to its grim prognosis. Unfortunately, only three SCCOHT cell lines are currently available for scientific research. In this study, we have successfully established a novel SCCOHT cell line from a recurrent lesion of a SCCOHT patient, named SCCOHT-CH-1. We comprehensively characterized the novel cell line by employing techniques such as morphological observation, CCK-8 assay, Transwell assay, clone formation assay, short tandem repeat sequence (STR) analysis, karyotype analysis, immunohistochemical staining, western blot assay, and xenograft tumor formation assay. SCCOHT-CH-1 cells were small circular and had a unique STR profile. The population-doubling time of SCCOHT-CH-1 was 33.02 h. The cell line showed potential migratory and invasive ability. Compared with another SCCOHT cell line COV434, SCCOHT-CH-1 exhibited higher expression of AKT, VIM, and CCND1. At the same time, SCCOHT-CH-1 has the ability of tumorigenesis in vivo. We also successfully constructed three patient-derived xenograft (PDX) models of SCCOHT, which were pathologically diagnosed to be consistent with the primary tumor, accompanied by loss of SAMRCA4 protein expression. The establishment of SCCOHT-CH-1 cell line and PDX models from Chinese people represent a pivotal step toward unraveling the molecular mechanism of SCCOHT and fostering the development of targeted interventions to tackle this challenging malignancy.

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EGFR tyrosine kinase inhibitors have made remarkable success in targeted cancer therapy. However, therapeutic resistance inevitably occurred and EGFR-targeting therapy has been demonstrated to have limited efficacy or utility in glioblastoma, colorectal cancer, and hepatocellular carcinoma. Therefore, there is a high demand for the development of new targets to inhibit EGFR signaling. Herein, we found that the EGFR oncogene proximal promoter sequence forms a unique type of snap-back loop containing G-quadruplex (G4), which can be targeted by small molecules. For the first time, we determined the NMR solution structure of this snap-back EGFR-G4, a three-tetrad-core, parallel-stranded G4 with naturally occurring flanking residues at both the 5'-end and 3'-end. The snap-back loop located at the 3'-end region forms a stable capping structure through two stacked G-triads connected by multiple potential hydrogen bonds. Notably, the flanking residues are consistently absent in reported snap-back G4s, raising the question of whether such structures truly exist under in vivo conditions. The resolved EGFR-G4 structure has eliminated the doubt and showed distinct structural features that distinguish it from the previously reported snap-back G4s, which lack the flanking residues. Furthermore, we found that the snap-back EGFR-G4 structure is highly stable and can form on an elongated DNA template to inhibit DNA polymerase. The unprecedented high-resolution EGFR-G4 structure has thus contributed a promising molecular target for developing alternative EGFR signaling inhibitors in cancer therapeutics. Meanwhile, the two stacked triads may provide an attractive site for specific small-molecule targeting.

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Host antiviral immunity suffers strong pressure from rapidly evolving viruses. Identifying host antiviral immune mechanisms has profound implications for developing antiviral strategies. Here, we uncover an essential role for the tumor suppressor Ras-association domain family (RASSF) in Drosophila antiviral response. Loss of dRassf in fat body leads to increased vulnerability to viral infection and impaired Imd pathway activation accompanied by detrimental JAK/STAT signaling overactivation. Mechanistically, dRASSF protects TAK1, a key kinase of Imd pathway, from inhibition by the STRIPAK PP2A phosphatase complex. Activated Imd signaling then employs the effector Relish to interfere with the dimerization of JAK/STAT transmembrane receptor Domeless, therefore preventing excessive JAK/STAT signaling. Moreover, we find that RASSF and STRIPAK PP2A complex are also involved in antiviral response in human cell lines. Our study identifies an important role for RASSF in antiviral immunity and elucidates a dRASSF-STRIPAK-Imd-JAK/STAT signaling axis that ensures proper antiviral responses in Drosophila.

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G-quadruplex is an essential element in gene transcription that serves as a promising drug target. Guanine-vacancy-bearing G-quadruplex (GVBQ) is a newly identified G-quadruplex that has distinct structural features from the canonical G-quadruplex. Potential GVBQ-forming motifs are widely distributed in gene promoter regions. However, whether GVBQ can form in genomic DNA and be an effective target for manipulating gene expression is unknown. Using photo-crosslinking, dimethyl sulfate footprinting, exonuclease digestion and in vitro transcription, we demonstrated the formation of a GVBQ in the G-rich nuclease hypersensitivity element within the human PDGFR-ß gene promoter region in both single-stranded and double-stranded DNA. The formation of GVBQ in dsDNA could be induced by negative supercoiling created by downstream transcription. We also found that the PDGFR-ß GVBQ was specifically recognized and stabilized by a new synthetic porphyrin guanine conjugate (mPG). Targeting the PDGFR-ß GVBQ in human cancer cells using the mPG could specifically alter PDGFR-ß gene expression. Our work illustrates that targeting GVBQ with mPG in human cells can regulate the expression level of a specific gene, thus indicating a novel strategy for drug development.

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A significant number of sequences in the human genome form noncanonical G-quadruplexes (G4s) with bulges or a guanine vacancy. Here, we systematically characterized the mechanical stability of parallel-stranded G4s with a one to seven nucleotides bulge at various positions. Our results show that G4-forming sequences with a bulge form multiple conformations, including fully-folded G4 with high mechanical stability (unfolding forces > 40 pN), partially-folded intermediates (unfolding forces < 40 pN). The folding probability and folded populations strongly depend on the positions and lengths of the bulge. By combining a single-molecule unfolding assay, dimethyl sulfate (DMS) footprinting, and a guanine-peptide conjugate that selectively stabilizes guanine-vacancy-bearing G-quadruplexes (GVBQs), we identified that GVBQs are the major intermediates of G4s with a bulge near the 5' or 3' ends. The existence of multiple structures may induce different regulatory functions in many biological processes. This study also demonstrates a new strategy for selectively stabilizing the intermediates of bulged G4s to modulate their functions.

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G-quadruplexes (G4s) formed by guanine-rich nucleic acids play a role in essential biological processes such as transcription and replication. Besides the >1.5 million putative G-4-forming sequences (PQSs), the human genome features >640 million single-nucleotide variations (SNVs), the most common type of genetic variation among people or populations. An SNV may alter a G4 structure when it falls within a PQS motif. To date, genome-wide PQS-SNV interactions and their impact have not been investigated. Herein, we present a study on the PQS-SNV interactions and the impact they can bring to G4 structures and, subsequently, gene expressions. Based on build 154 of the Single Nucleotide Polymorphism Database (dbSNP), we identified 5 million gains/losses or structural conversions of G4s that can be caused by the SNVs. Of these G4 variations (G4Vs), 3.4 million are within genes, resulting in an average load of >120 G4Vs per gene, preferentially enriched near the transcription start site. Moreover, >80% of the G4Vs overlap with transcription factor-binding sites and >14% with enhancers, giving an average load of 3 and 7.5 for the two regulatory elements, respectively. Our experiments show that such G4Vs can significantly influence the expression of their host genes. These results reveal genome-wide G4Vs and their impact on gene activity, emphasizing an understanding of genetic variation, from a structural perspective, of their physiological function and pathological implications. The G4Vs may also provide a unique category of drug targets for individualized therapeutics, health risk assessment, and drug development.

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G-quadruplex (G4) structures formed by guanine-rich nucleic acids are implicated in essential physiological and pathological processes and serve as important drug targets. The genome-wide detection of G4s in living cells is important for exploring the functional role of G4s but has not yet been achieved due to the lack of a suitable G4 probe. Here we report an artificial 6.7 kDa G4 probe (G4P) protein that binds G4s with high affinity and specificity. We used it to capture G4s in living human, mouse, and chicken cells with the ChIP-Seq technique, yielding genome-wide landscape as well as details on the positions, frequencies, and sequence identities of G4 formation in these cells. Our results indicate that transcription is accompanied by a robust formation of G4s in genes. In human cells, we detected up to >123 000 G4P peaks, of which >1/3 had a fold increase of ≥5 and were present in >60% promoters and ∼70% genes. Being much smaller than a scFv antibody (27 kDa) or even a nanobody (12-15 kDa), we expect that the G4P may find diverse applications in biology, medicine, and molecular devices as a G4 affinity agent.

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Telomerase, a key enzyme involved in telomere homeostasis, is a major player involved in or required for sustained cell proliferation. It is expressed in ∼90% tumor but rarely in normal somatic cells. Therefore, telomerase serves as a diagnostic marker and therapeutic target of cancers. Although many methods are available for measuring telomerase activity, a convenient, fast, sensitive, and reliable method is still lacking for routine use in both clinics and research. Here, we present a single-enzyme sensitivity telomere repeat amplification protocol for quantifying telomerase activity. With multiple optimizations, the protocol pushes the ultimate detection limit down to a single telomerase complex, enabling measurement of telomerase activity of not only multiple cancerous/normal cell samples but also single cancer cells alone or even in the presence of 8000 normal cells. Implemented in a one-step mix-and-run format, the protocol offers a most sensitive, fast, accurate, and reproducible quantification of telomerase activity with linearity ranging from 20,000 HeLa cancer cells to a single telomerase complex. It requires minimal manual operation and experimental skill and is convenient for either low or high throughput of samples. We expect that the protocol should provide practical routine analyses of telomerase in both research and clinical applications. As an example, we demonstrate how telomerase activity evolves at the single-cell level and partitions in cell division in early mouse embryo development.

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Stabilization of G-quadruplexes (G4s) formed in guanine-rich (G-rich) nucleic acids by small-molecule ligands has been extensively explored as a therapeutic approach for diseases such as cancer. Finding ligands with sufficient affinity and specificity toward G4s remains a challenge, and many ligands reported seemed to compromise between the two features. To cope with this challenge, we focused on targeting a particular type of G4s, i.e., the G-vacancy-bearing G-quadruplexes (GVBQs), by taking a structure complementation strategy to enhance both affinity and selectivity. In this approach, a G-quadruplex-binding peptide RHAU23 is guided toward a GVBQ by a guanine moiety covalently linked to the peptide. The filling-in of the vacancy in a GVBQ by the guanine ensures an exclusive recognition of GVBQ. Moreover, the synergy between the RHAU23 and the guanine dramatically improves both the affinity toward and stabilization of the GVBQ. Targeting a GVBQ in DNA by this bifunctional peptide strongly suppresses in vitro replication. This study demonstrates a novel and promising alternative targeting strategy to a distinctive panel of G4s that are as abundant as the canonical ones in the human genome.

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A dual-functional peptide-PNA (peptide nucleic acid) conjugate consisting of a PNA G3-tract and an RHAU23 peptide is devised to target nucleic acids bearing three tandem guanine tracts (G-tracts). The PNA G3-tract joins the three G-tracts to form a stable bimolecular G-quadruplex (G4) and the resulting G4 is then bound by the RHAU23 moiety to form an extra stable G4-peptide complex. Owing to this synergistic dual structural enforcement, the conjugate accomplished extremely high selectivity and nM to sub-nM affinities towards its targets that are up to 1000 times greater than the small molecule G4 ligands. As a result, the conjugate impacts the tracking activity of motor proteins on DNA with superior selectivity and potency that are rarely seen in other G4-targeting approaches.

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The particular enrichment of G-quadruplex-forming sequences near transcription start sites signifies the involvement of G-quadruplexes in the regulation of transcription. The characterization of G-quadruplex formation, which holds the key to understand the function it plays in physiological and pathological processes, is mostly performed under simplified in vitro experimental conditions. Formation of G-quadruplexes in cells, however, occurs in an environment far different from the ones in which the in vitro studies on G-quadruplexes are normally carried out. Therefore, the characteristics of G-quadruplex structures obtained under the in vitro conditions may not faithfully reveal how the G-quadruplexes would behave in a physiologically relevant situation. In this mini-review, we attempt to briefly summarize the differences in a few important characteristics, including kinetics, conformation, and stability of G-quadruplex formation observed under the two conditions to illustrate how the intracellular environment might affect the behavior of G-quadruplexes largely based on the previous work carried out in the authors' laboratory. We also propose that unstable G-quadruplex variants may be better drug target candidates to improve selectivity and potency.

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