Trypsin in colorectal cancer: molecular biological mechanisms of proliferation, invasion, and metastasis

The in vitro and crystallographic studies reveal the inhibitory potential of vitamin B6 analogues against a serine protease trypsin

Trypsin is a representative member of serine protease family of peptidases. Its premature activation leads to develop several ailments, such as pancreatitis and colorectal cancer. The available therapies are few in numbers and possessed several side effects. Therefore, searching of new trypsin inhibitors has a great importance in drug discovery. In the current study, we have discovered the inhibitory potential of vitamin B6 and its commercially available analogues; pyridoxine (1), pyridoxal (2), pyridoxamine (3) and pyridoxal phosphate (4), against trypsin through in vitro and crystallographic approaches. Compound 1 (pyridoxine) and 2 (pyridoxal) showed significant inhibitory potential against trypsin with the IC50 of 234.99 ± 1.41 and 235.98 ± 1.41 μM, respectively and they did not show any significant difference in their IC50 values (p > 0.05). The mechanistic studies reveal that both molecules showed noncompetitive mode of inhibition against trypsin enzyme. The crystallographic studies reveal the binding of compounds 1 and 2 within the S1 pocket of enzyme in two different conformations. Both conformations were stabilized with hydrogen bonding. They mostly showed interactions with Ser195, a key residue of the active site.

Non-classical neutrophil extracellular traps induced by PAR2-signaling proteases

Neutrophil extracellular traps (NETs) are associated with diseases linked to aberrant coagulation. The blood clotting cascade involves a series of proteases, some of which induce NET formation via a yet unknown mechanism. We hypothesized that this formation involves signaling via a factor Xa (FXa) activation of the protease-activated receptor 2 (PAR2). Our findings revealed that NETs can be triggered in vitro by enzymatically active proteases and PAR2 agonists. Intravital microscopy of the liver vasculature revealed that both FXa infusion and activation of endogenous FX promoted NET formation, effects that were prevented by the FXa inhibitor, apixaban. Unlike classical NETs, these protease-induced NETs lacked bactericidal activity and their proteomic signature indicates their role in inflammatory disorders, including autoimmune diseases and carcinogenesis. Our findings suggest a novel mechanism of NET formation under aseptic conditions, potentially contributing to a self-amplifying clotting and NET formation cycle. This mechanism may underlie the pathogenesis of disseminated intravascular coagulation and other aseptic conditions.

Trypsin-instructed bioactive peptide nanodrugs with cascading transformations to improve chemotherapy against colon cancer

Chemotherapy remains an effective treatment for colon cancer but is hampered by its limited response rate. Bioactive peptides, marked with intracellular transformations, have been reported as an effective approach to boosting chemotherapeutic activity. Herein, a promising trypsin-responsive bioactive peptide-based nanodrug is constructed, which could significantly prolong the drug retention time in vivo by cascading transformations and improve chemotherapeutic efficacy. Initially, 1-Pept co-assembles with Dox into a few nanofibers called 1-Pept/Dox NFs, inducing an enhanced cellular uptake via caveolae-mediated endocytosis by avoiding lysosomal degradation and further promoting perinuclear transportation, thus enlarging the drug efficacy in target areas. After nanofiber disassembly, the released 1-Pept converts into Pept under the catalysis of intracellular overexpressed trypsin, which then reassembles into denser Pept NFs, inducing a cascade of effects including disruption of the cytoskeleton, mitochondrial dysfunction, and activation of caspase-3. By the synergism of Pept NFs and Dox, caspase-3 can be further activated, and cause greater damage to nuclear, thereby leading to tumor ablation. As the first example of employing trypsin-mediated nanodrugs with cascading transformations to promote chemotherapeutic activity, this work promises a strategy for novel therapies for efficiently combating colon cancer.

A Pyrene-Derived Fluorescent Probe for the Visual Detection of Protamine and Trypsin Activity

A pyrene-derived fluorescent probe (P4CG) was designed and synthesized for the purpose of detecting protamine and trypsin activity. The anionic probe self-assembled with protamine, driven by electrostatic and hydrophobic interactions, exhibiting a sensing behavior towards protamine in a fluorescence ratiometric manner. The assay demonstrated high sensitivity, with a limit of detection (LOD) of 13.8 ng/mL, and exhibited selectivity in the HEPES buffer solution. Moreover, the P4CG-protamine complex enables the monitoring of trypsin activity with satisfactory sensitivity and selectivity. The presence of the trypsin inhibitor resulted in the inhibition of the hydrolysis of protamine, which in turn led to a diminished fluorescence recovery. Consequently, this assay can be employed for the screening of trypsin inhibitors.

Effect of Water Networks On Ligand Binding: Computational Predictions vs Experiments

Rational drug design focuses on the explanation and prediction of complex formation between therapeutic targets and small-molecule ligands. As a third and often overlooked interacting partner, water molecules play a critical role in the thermodynamics of protein-ligand binding, impacting both the entropy and enthalpy components of the binding free energy and by extension, on-target affinity and bioactivity. The community has realized the importance of binding site waters, as evidenced by the number of computational tools to predict the structure and thermodynamics of their networks. However, quantitative experimental characterization of relevant protein-ligand-water systems, and consequently the validation of these modeling methods, remains challenging. Here, we investigated the impact of solvent exchange from light (H2O) to heavy water (D2O) to provide complete thermodynamic profiling of these ternary systems. Utilizing the solvent isotope effects, we gain a deeper understanding of the energetic contributions of various components. Specifically, we conducted isothermal titration calorimetry experiments on trypsin with a series of p-substituted benzamidines, as well as carbonic anhydrase II (CAII) with a series of aromatic sulfonamides. Significant differences in binding enthalpies found between light vs heavy water indicate a substantial role of the binding site water network in protein-ligand binding. Next, we challenged two conceptually distinct modeling methods, the grid-based WaterFLAP and the molecular dynamics-based MobyWat, by predicting and scoring relevant water networks. The predicted water positions accurately reproduce those in available high-resolution X-ray and neutron diffraction structures of the relevant protein-ligand complexes. Estimated energetic contributions of the identified water networks were corroborated by the experimental thermodynamics data. Besides providing a direct validation for the predictive power of these methods, our findings confirmed the importance of considering binding site water networks in computational ligand design.

Small molecule protein assembly modulators with pan-cancer therapeutic efficacy

Two structurally unrelated small molecule chemotypes, represented by compounds PAV-617 and PAV-951, with antiviral activity in cell culture against Mpox virus (formerly known as monkeypox virus) and human immunodeficiency virus (HIV) respectively, were studied for anti-cancer efficacy. Each exhibited apparent pan-cancer cytotoxicity with reasonable pharmacokinetics. Non-toxicity is demonstrated in a non-cancer cell line and in mice at doses achieving drug exposure at active concentrations. Anti-tumour properties of both chemotypes were validated in mouse xenografts against A549 human lung cancer and, for one of the chemotypes, against HT-29 colorectal cancer. The targets of these compounds are unconventional: each binds to a different transient, energy-dependent multi-protein complex. Treatment with these compounds alters the target multi-protein complexes in a manner that appears to remove a block, crucial for cancer survival and progression, on a homeostatic linkage between uncontrolled proliferation and apoptosis. These compounds provide starting points for development of novel, next-generation, non-toxic, pan-cancer therapeutics.

Structural basis for the binding of famotidine, cimetidine, guanidine, and pimagedine with serine protease

Serine proteases are among the important groups of enzymes having significant roles in cell biology. Trypsin is a representative member of the serine superfamily of enzymes, produced by acinar cells of pancreas. It is a validated drug target for various ailments including pancreatitis and colorectal cancer. Premature activation of trypsin is involved in the lysis of pancreatic tissues, which causes pancreatitis. It is also reported to be involved in colorectal carcinoma by activating other proteases, such as matrix metalloproteinase (MMPs). The development of novel trypsin inhibitors with good pharmacokinetic properties could play important roles in pharmaceutical sciences. This study reports the crystal structures of bovine pancreatic trypsin with four molecules; cimetidine, famotidine, pimagedine, and guanidine. These compounds possess binding affinity towards the active site (S1) of trypsin. The structures of all four complexes provided insight of the binding of four different ligands, as well as the dynamics of the active site towards the bind with different size ligands. This study might be helpful in designing of new potent inhibitors of trypsin and trypsin like serine proteases.

In vitro, in silico and crystallographic-based identification of serine protease inhibitors

Serine proteases are involved in various ailments, including pancreatitis, and colon cancer. Based on substrate recognition serine proteases are classified into different groups. Trypsin and trypsin-like serine proteases are among most studied group of serine proteases. Trypsin is among the chief hydrolysing enzyme involved in the pathogenesis of pancreatitis. Its inhibition can help to manage the disease. Herein, we investigated the trypsin inhibitory effect of some arginine-based small molecules, through in vitro, in silico, and crystallographic methods. Compounds 1-3 were evaluated against bovine pancreatic trypsin (BPT). Compound 1 was found to be active against trypsin with IC50 value of 247.98 ± 2.44 μM. Molecular docking studies were used to investigate the binding energy and binding conformation of inhibitor. All three compounds were subjected to crystallisation with trypsin. Compounds 1-2 were successfully crystallised with BPT The crystal structures of trypsin in complexed with compounds 1, and 2 were determined at 2.30 and 2.50 Å resolution, respectively. Both molecules showed their binding affinity with the active site residues of trypsin. This study will provide insight into the binding mechanism of E-64 and arginine and might be useful in designing effective inhibitors of serine proteases.

Coating Dormant Collagenase-Producing Bacteria with Metal-Anesthetic Networks for Precision Tumor Therapy

Tumor malignancy highly depends on the stiffness of tumor matrix, which mainly consists of collagen. Despite the destruction of tumor matrix is conducive to tumor therapy, it causes the risk of tumor metastasis. Here, metal-anesthetic network-coated dormant collagenase-producing Clostridium is constructed to simultaneously destruct tumor matrix and inhibit tumor metastasis. By metal-phenolic complexation and π-π stacking interactions, a Fe3+-propofol network is formed on bacterial surface. Coated dormant Clostridium can selectively germinate and rapidly proliferate in tumor sites due to the ability of carried Fe3+ ions to promote bacterial multiplication. Intratumoral colonization of Clostridium produces sufficient collagenases to degrade tumor collagen mesh and the loaded propofol restrains tumor metastasis by inhibiting tumor cell migration and invasion. Meanwhile, the delivered Fe3+ ions are reduced to the Fe2+ form by intracellular glutathione, thereby inducing potent Fenton reaction to trigger lipid peroxidation and ultimate ferroptosis of tumor cells. In addition to a satisfactory safety, a single intratumoral injection of coated dormant Clostridium not only effectively retards the growth of established large primary tumors, but also significantly suppresses distal lung metastasis in two different orthotopic tumor models. This work proposes a strategy to develop advanced therapeutics for malignant tumor treatment and metastasis prevention.

An overview of the direct interaction of synthesized silver nanostructures and enzymes

Silver nanoparticles (AgNPs) have drawn a lot of attention from a variety of fields, particularly the biological and biomedical sciences. As a result, it is acknowledged that AgNPs' direct interactions with macromolecules such as DNA, proteins, and enzymes are essential for both therapeutic and nanotoxicological applications. Enzymes as important catalysts may interact with AgNP surfaces in a variety of ways. Therefore, mechanistic investigation into the molecular effects of AgNPs on enzyme conformation and function is necessary for a comprehensive assessment of their interactions. In this overview, we aimed to overview the various strategies for producing AgNPs. We then discussed the enzyme activity inhibition (EAI) mechanism by nanostructured particles, followed by an in-depth survey of the interaction of AgNPs with different enzymes. Furthermore, various parameters influencing the interaction of NPs and enzymes, as well as the antibacterial and anticancer effects of AgNPs in the context of the enzyme inhibitors, were discussed. In summary, useful information regarding the biological safety and possible therapeutic applications of AgNPs-enzyme conjugates may be obtained from this review.

Enzymatic response of heparin-protamine complex: Spectroscopic investigation and application for lung adenocarcinoma cells detection

Though the heparin-protamine complex (HP complex) is a crucial system utilized in clinical settings, the metabolic pathways of this complex remain inadequately understood. Herein, the enzymatic degradation of the heparin-protamine complex by trypsin and its broader implications were investigated. By utilizing fluorescent gold nanoclusters liganded with the HP complex (AuNCs-HP complex), we observed significant morphological and spectral changes during enzymatic degradation. Experiments showed that AuNCs-HP complex could be degraded and cleaved into small fragments by trypsin. Moreover, the AuNCs-HP complex demonstrated its potential as a highly sensitive spectral sensing platform, enabling precise measurement of trypsin activity with an outstanding detection limit (0.34 ng mL-1). Additionally, we explored its utility for specific tumor cell detection, focusing on lung adenocarcinoma cells, and successfully identified their presence through distinctive fluorescence changes. These remarkable findings not only contribute valuable insights into targeted degradation systems but also offer promising opportunities for cancer biomarker detection. The AuNCs-HP complex serves as an innovative tool for real-time trypsin activity monitoring, paving the way for advanced biomedical applications.

NIR-Sensitive Squaraine Dye-Peptide Conjugate for Trypsin Fluorogenic Detection

Trypsin enzyme has gained recognition as a potential biomarker in several tumors, such as colorectal, gastric, and pancreatic cancer, highlighting its importance in disease diagnosis. In response to the demand for rapid, cost-effective, and real-time detection methods, we present an innovative strategy utilizing the design and synthesis of NIR-sensitive dye-peptide conjugate (SQ-3 PC) for the sensitive and selective monitoring of trypsin activity by fluorescence ON/OFF sensing. The current research deals with the design and synthesis of three unsymmetrical squaraine dyes SQ-1, SQ-2, and SQ-3 along with a dye-peptide conjugate SQ-3-PC as a trypsin-specific probe followed by their photophysical characterizations. The absorption spectral investigation conducted on both the dye alone and its corresponding dye-peptide conjugates in water, utilizing SQ-3 and SQ-3 PC respectively, reveals enhanced dye aggregation and pronounced fluorescence quenching compared to observations in DMSO solution. The absorption spectral investigation conducted on dye only and corresponding dye-peptide conjugates in water utilizing SQ-3 and SQ-3 PC, respectively, reveals not only the enhanced dye aggregation but also pronounced fluorescence quenching compared to that observed in the DMSO solution. The trypsin-specific probe SQ-3 PC demonstrated a fluorescence quenching efficiency of 61.8% in water attributed to the combined effect of aggregation-induced quenching (AIQ) and fluorescence resonance energy transfer (FRET). FRET was found to be dominant over AIQ. The trypsin-mediated hydrolysis of SQ-3 PC led to a rapid and efficient recovery of quenched fluorescence (5-fold increase in 30 min). Concentration-dependent changes in the fluorescence at the emission maximum of the dyes reveal that SQ-3 PC works as a trypsin enzyme-specific fluorescence biosensor with linearity up to 30 nM along with the limit of detection and limit of quantification of 1.07 nM and 3.25 nM, respectively.

Purification and partial physical-chemical characterization of a new bovine trypsin proteoform (zeta-trypsin)

Recent advancements in enzyme research have unveiled a new proteoform of bovine trypsin, expanding our understanding of this well-characterized enzyme. While generally similar to other trypsins, this novel proteoform comprises three polypeptide chains, marking a significant difference in activity, kinetic properties, and conformational stability. Compared with the already known bovine trypsin proteoforms, the results showed a lower: activity, kcat and kcat.KM-1 and protein 'foldedness' ratio for the new proteoform. Molecular autolysis, a common feature in trypsin and chymotrypsin, has been explored through comparative physical chemistry properties with other proteoforms. This new proteoform of trypsin not only enriches the existing enzyme repertoire but also promises to shed light on the intricate physiological pathway for enzyme inactivation. Our results suggest that the new trypsin proteoform is one of the likely final pathways for enzyme inactivation in a physiological environment. This discovery opens up new avenues for further research into the functional implications of this new trypsin proteoform.

Conformational dynamics of trypsin in the presence of caffeic acid: a spectroscopic and computational investigation

Caffeic acid is one of the widely distributed phenolic compounds in nature and can be found in planet products. On the other hand, trypsin is a vital digestive enzyme in the intestine that plays an essential role in the immune response, blood coagulation, apoptosis and protein maturation like protein digestion. Several studies have revealed the inhibitory effects of the phenolic compound on the digestive enzyme. The present study reports functional and conformational alteration of trypsin after caffeic acid addition using multiple experimental and computational techniques for the first time. The intrinsic fluorescence of trypsin is quenched in the presence of caffeic acid via a static mechanism. The percent of secondary structures (α-helix and β-sheet) of trypsin alter after caffeic acid addition. In the kinetic study, a reduction in the trypsin function is obtained with a lower Vmax and Kcat upon interaction with caffeic acid. The thermal study reveals an unstable structure of trypsin upon complex formation with this phenolic compound. Also, the binding sites and conformational changes of trypsin are elucidated through molecular docking and molecular dynamic simulation.Communicated by Ramaswamy H. Sarma.

Low-Dose Trypsin Accelerates Wound Healing via Protease-Activated Receptor 2

The management of wounds remains a significant healthcare challenge, highlighting the need for effective wound healing strategies. To address this, it is crucial to explore the molecular mechanisms underlying tissue repair as well as explore potential therapeutic approaches. Trypsin, as a serine protease, has been clinically utilized for wound healing for decades; however, it still lacks systemic investigation on its role and related mechanism. This study aimed to investigate the effects of low-dose trypsin on wound healing both in vitro and in vivo. While trypsin is an endogenous stimulus for protease-activated receptor 2 (PAR2), we discovered that both low-dose trypsin and synthesized PAR2 agonists significantly enhanced the migration, adhesion, and proliferation of fibroblasts and macrophages, similar to the natural repair mechanism mediated by mast cell tryptase. Moreover, such cell functions induced by trypsin were largely inhibited by PAR2 blockade, indicating the participation of trypsin via PAR2 activation. Additionally, low-dose trypsin notably expedited healing and regeneration while enhancing collagen deposition in skin wounds in vivo. Importantly, upon stimulation of trypsin or PAR2 agonists, there were significant upregulations of genes including claudin-7 (Cldn7), occludin (Ocln), and interleukin-17A (IL-17A) associated with proliferation and migration, extracellular matrix (ECM), tight junction, and focal adhesion, which contributed to wound healing. In summary, our study suggested that a low-dose trypsin could be a promising strategy for wound healing, and its function was highly dependent on PAR2 activation.

Enzyme and pH dual responsive linear-dendritic block copolymer micelles based on a phenylalanyl-lysine motif and peripherally ketal-functionalized dendron as potential drug carriers

Stimuli-responsive linear-dendritic block copolymers (LDBCs) have attracted significant research attention as novel drug carriers. We report here three generations of new enzyme and pH dual responsive linear-dendritic block copolymers (LDBCs) with a phenylalanyl-lysine (Phe-Lys) dipeptide linking hydrophilic linear poly(N-vinylpyrrolidone) (PNVP) and a hydrophobic peripherally ketal-functionalized dendron derived from 2,2'-bis(hydroxymethyl)propionic acid (bis-MPA). The LDBCs are synthesized via a combination of interchange of xanthates/reversible addition-fragmentation chain transfer (MADIX/RAFT) polymerization of N-vinylpyrrolidone (NVP) and "chain-first" strategy. Their structures are confirmed by ¹H NMR spectra. The gel permeation chromatograph (GPC) analysis revealed that the LDBCs have a narrow molecular weight distribution (PDI ≤ 1.25). The amphiphilic LDBCs can self-assemble into spherical nanomicelles in aqueous solution. The presence of enzyme or/and the change of pH cause disassembly of micelles to release encapsulated cargos. The release rates of the guest molecules are faster in buffer solution at pH 5.0 than those upon the addition of the activating enzyme and can be fine-tuned by changing the generation of bis-MPA dendrons. The combination of enzyme and pH dual stimuli results in significantly accelerated and more complete release of the loaded hydrophobic guests. The cell viability assay confirmed the favorable biocompatibility until the LDBC micelle concentration reached 800 μg mL^-1. These results indicate that the LDBCs can be considered as a good candidate for targeting drug delivery.

Upamostat: a serine protease inhibitor for antiviral, gastrointestinal, and anticancer indications

INTRODUCTION

Serine proteases are involved in many normal metabolic processes but also contribute to diseases of several organ systems, including viral and gastrointestinal diseases and oncology. Upamostat is an orally bioavailable prodrug of WX-UK1, which is most active against trypsins and closely related enzymes.

AREAS COVERED

Research over the past two decades suggests several diseases in the three areas noted above which upamostat may be active. Upamostat has been studied clinically against several cancers and for outpatient treatment of COVID-19. Preclinical and clinical pharmacokinetic and metabolism studies demonstrate good bioavailability, sustained tissue levels, and high concentrations of the active moiety, WX-UK1, in stool, potentially important for treatment of gastrointestinal diseases. Clinical studies suggest activity against SARS-CoV-2; results against pancreatic cancer are also encouraging, though studies in both indications are not definitive. The drug was very well tolerated for periods of 2 weeks to several months.

EXPERT OPINION

Upamostat is an orally bioavailable serine protease inhibitor with an excellent safety profile and favorable pharmacokinetic properties. It has demonstrated preliminary evidence of efficacy against COVID-19, and nonclinical data suggest potential applicability against other viral illnesses, gastrointestinal diseases, and cancer.

Dual-Functional Capping Agent-Mediated Transformation of Silver Nanotriangles to Silver Nanoclusters for Dual-Mode Biosensing

The localized surface plasmon resonance (LSPR) property, depending on the structure (morphology and assembly) of nanoparticles, is very sensitive to the environmental fluctuation. Retaining the colorimetric effect derived from the LSPR property while introducing new optical properties (such as fluorescence) that provide supplementary information is an effective means to improve the controllability in structures and reproducibility in optical properties. DNA as a green and low-cost etching agent has been demonstrated to effectively control the morphology and optical properties (the blue shift of the LSPR peak) of the plasmonic nanoparticles. Herein, taking silver nanotriangles (AgNTs) as a proof of concept, we report a novel strategy to induce precisely tunable LSPR and fluorescence-composited dual-mode signals by using mono-DNA first as an etching agent for etching the morphology of AgNTs and later as a template for synthesizing fluorescent silver nanoclusters (AgNCs). In addition, common templates for synthesizing AgNCs, such as l-glutathione and bovine serum albumin, were demonstrated to have the capability to serve as etching agents. More importantly, these biomolecules as dual-functional capping agents (etching agents and templates) follow the size-dependent rule: as the size of the thiolated biomolecule increases, the blue shift of the LSPR peak increases; at the same time, the fluorescence intensity increases. The enzyme that can change the molecular weight (size) of the biomolecular substrates (DNA, peptides, and proteins) through an enzymatic cleavage reaction was explored to regulate the LSPR and fluorescent properties of the resulting nanoparticles (by etching of AgNTs and synthesis of AgNCs), achieving excellent performance in detection of cancer-related proteases. This study can be expanded to other biopolymers to impact both fundamental nanoscience and applications and provide powerful new tools for bioanalytical biosensors and nanomedicine.

Protease-activated indocyanine green nanoprobes for intraoperative NIR fluorescence imaging of primary tumors

Tumor-targeted fluorescent probes in the near-infrared spectrum can provide invaluable information about the location and extent of primary and metastatic tumors during intraoperative procedures to ensure no residual tumors are left in the patient's body. Even though the first fluorescence-guided surgery was performed more than 50 years ago, it is still not accepted as a standard of care in part due to the lack of efficient and non-toxic targeted probes approved by regulatory agencies around the world. Herein, we report protease-activated cationic gelatin nanoparticles encapsulating indocyanine green (ICG) for the detection of primary breast tumors in murine models with high tumor-to-background ratios. Upon intravenous administration, these nanoprobes remain optically silent due to the energy resonance transfer among the bound ICG molecules. As the nanoprobes extravasate and are exposed to the acidic tumor microenvironment, their positive surface charges increase, facilitating cellular uptake. The internalized nanoprobes are activated upon proteolytic degradation of gelatin to allow high contrast between the tumor and normal tissue. Since both gelatin and ICG are FDA-approved for intravenous administration, this activatable nanoprobe can lead to quick clinical adoption and improve the treatment of patients undergoing image-guided cancer surgery.

Integrated bioinformatics analysis reveals potential mechanisms associated with intestinal flora intervention in nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease that imposes a huge economic burden on global public health. And the gut-liver axis theory supports the therapeutic role of intestinal flora in the development and progression of NAFLD. To this end, we designed bioinformatics study on the relationship between intestinal flora disorder and NAFLD, to explore the possible molecular mechanism of intestinal flora interfering with NAFLD.

METHODS

Differentially expressed genes for NAFLD were obtained from the GEO database. And the disease genes for NAFLD and intestinal flora disorder were obtained from the disease databases. The protein-protein interaction network was established by string 11.0 database and visualized by Cytoscape 3.7.2 software. Cytoscape plug-in MCODE and cytoHubba were used to screen the potential genes of intestinal flora disorder and NAFLD, to obtain potential targets for intestinal flora to interfere in the occurrence and process of NAFLD. Enrichment analysis of potential targets was carried out using R 4.0.2 software.

RESULTS

The results showed that 7 targets might be the key genes for intestinal flora to interfere with NAFLD. CCL2, IL6, IL1B, and FOS are mainly related to the occurrence and development mechanism of NAFLD, while PTGS2, SPINK1, and C5AR1 are mainly related to the intervention of intestinal flora in the occurrence and development of NAFLD. The gene function is mainly reflected in basic biological processes, including the regulation of metabolic process, epithelial development, and immune influence. The pathway is mainly related to signal transduction, immune regulation, and physiological metabolism. The TNF signaling pathway, AGE-RAGE signaling pathway in diabetic activity, and NF-Kappa B signaling pathways are important pathways for intestinal flora to interfere with NAFLD. According to the analysis results, there is a certain correlation between intestinal flora disorder and NAFLD.

CONCLUSION

It is speculated that the mechanism by which intestinal flora may interfere with the occurrence and development of NAFLD is mainly related to inflammatory response and insulin resistance. Nevertheless, further research is needed to explore the specific molecular mechanisms.

Higher amoebic and metronidazole resistant forms of Blastocystis sp. seen in schizophrenic patients

Background

Blastocystis sp. is one of the most common colonisers of the intestinal tract that demonstrate strong interaction with accompanying gut bacteria. Previously, the protozoan isolated from individuals with irritable bowel syndrome (IBS) showed altered phenotypic features suggesting that it can be triggered to become pathogenic. Previous studies reported altered gut microbiota and high prevalence of Blastocystis sp. in schizophrenia patients. However, the phenotypic characteristics of Blastocystis sp. isolated from individuals with SZ have yet to be described.

Methods

In this study, faecal samples from 50 patients with severe schizophrenia (SZ) and 100 non-schizophrenic (NS) individuals were screened for Blastocystis sp. infection. Positive isolates were subjected to genotypic and phenotypic characterization.

Results

We found that 12 out of 50 (24%) SZ and 5 out of 100 (5%) NS individuals were detected Blastocystis sp. positive using both in vitro culture and PCR method with no significant association to age and gender. Out of the 15 sequenced isolates, ST3 was the most prevalent subtype (66.7%) followed by ST1 (20%) and ST6 (13.3%). The isolates from SZ individuals demonstrated significant slower growth rate (34.9 ± 15.6 h) and larger range of cell diameter (3.3–140 µm). We detected higher amoebic forms and metronidazole resistance among SZ isolates with variation in cell surface glycoprotein where 98% of cells from SZ showed consistent medium to high binding affinity (+ 2 to + 3) to Concavalin A staining compared to NS isolates that demonstrated only 76% high lectin (+ 3) binding affinity. Cysteine and serine protease levels were predominantly found among SZ isolates. We also demonstrate the presence of metalloprotease in Blastocystis sp. especially among NS isolates. Introduction of solubilised antigens from SZ isolates increased the cell proliferation of HCT116 cells by two fold when compared to NS isolates.

Conclusion

Our findings demonstrated Blastocystis sp. isolated from SZ individuals showed variation in phenotype specifically in morphology and drug resistance. The findings indicate that the gut environment (SZ and NS) and treatment of SZ could have influenced the phenotype of Blastocystis sp.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05418-0.

Nuclear magnetic resonance spectroscopy reveals dysregulation of monounsaturated fatty acid metabolism upon SPINK1 attenuation in colorectal cancer

Metabolic reprogramming, a key hallmark of cancer, plays a pivotal role in fulfilling the accelerated biological demands of tumor cells. Such metabolic changes trigger the production of several proinflammatory factors, thereby inciting cancer development and its progression. Serine protease inhibitor Kazal Type 1 (SPINK1), well known for its oncogenic role and its upregulation via acute-phase reactions, is highly expressed in multiple cancers including colorectal cancer (CRC). Here, we show accumulation of lipid droplets in CRC cells stained with Oil Red O upon SPINK1 silencing. Furthermore, NMR spectroscopy analysis revealed an accretion of monounsaturated fatty acids (MUFAs) and phosphatidylcholine in these CRC cells, while the levels of polyunsaturated fatty acids remained unaltered. This alteration indicates the presence of MUFAs with the triglycerides in the lipid droplets as observed in SPINK1-silenced CRC cells. Considering the role of MUFAs in the anti-inflammatory response, our data hint that suppression of SPINK1 in CRC leads to activation of an anti-inflammatory signaling milieu. Conclusively, our study uncovers a connection between lipid metabolism and SPINK1-mediated CRC progression, hence paving the way for further exploration and better prognosis of SPINK1-positive CRC patients.

Biological Evaluation, Molecular Docking Analyses, and ADME Profiling of Certain New Quinazolinones as Anti-colorectal Agents

Colorectal carcinogenesis is a complex process, which is linked to dysregulation of human secretory phospholipases A₂ (hsPLA₂-G-IIA, hsPLA₂-G-V, and hsPLA₂-G-X), proteases (cathepsin-B, collagenase, thrombin, elastase, and trypsin), carbohydrate hydrolyzing enzymes (α-amylase and α-glucosidase), and free radical generating enzyme (xanthine oxidoreductase (XOR)). Therefore, some new quinazolinones were synthesized and evaluated as inhibitors against this array of enzymes as well as cytotoxic agents on LoVo and HCT-116 cells of colorectal cancer. Compounds 3g, 10, 8, 3c, and 1c exhibited promising cytotoxic effects with IC₅₀ values ranging from 206.07 to 459.79 μM. Nine compounds showed promising enzymatic inhibitory effects, 3b, 3d, 3f, 5, 1a, and 12 (α-amylase), 8 (thrombin, elastase and trypsin), 10 (hsPLA₂-G-IIA and hsPLA₂-G-V), and 3f (α-glucosidase and XOR). Therefore, the most active inhibitors, were subjected to validated molecular docking studies to identify their affinities and binding modes. The expected physicochemical and pharmacokinetic features of the active candidates, 1a, 1c, 3b, 3c, 3d, 3f, 3g, 5, 8, 10, and 12 were predicted using bioavailability radar charts and boiled-egg graphical representations along with the Lipinski rule of five filter. Collectively, these studies showed the significance of derivatives 1c, 3b, 3c, 3d, 8, 10, and 12 as lead scaffolds for further optimization to develop enzymes inhibitors and anti-colorectal agents.

Designing bioresponsive nanomaterials for intracellular self-assembly

Supramolecular assemblies are essential components of living organisms. Cellular scaffolds, such as the cytoskeleton or the cell membrane, are formed via secondary interactions between proteins or lipids and direct biological processes such as metabolism, proliferation and transport. Inspired by nature’s evolution of function through structure formation, a range of synthetic nanomaterials has been developed in the past decade, with the goal of creating non-natural supramolecular assemblies inside living mammalian cells. Given the intricacy of biological pathways and the compartmentalization of the cell, different strategies can be employed to control the assembly formation within the highly crowded, dynamic cellular environment. In this Review, we highlight emerging molecular design concepts aimed at creating precursors that respond to endogenous stimuli to build nanostructures within the cell. We describe the underlying reaction mechanisms that can provide spatial and temporal control over the subcellular formation of synthetic nanostructures. Showcasing recent advances in the development of bioresponsive nanomaterials for intracellular self-assembly, we also discuss their impact on cellular function and the challenges associated with establishing structure–bioactivity relationships, as well as their relevance for the discovery of novel drugs and imaging agents, to address the shortfall of current solutions to pressing health issues.

Creating artificial nanostructures inside living cells requires the careful design of molecules that can transform into active monomers within a complex cellular environment. This Review explores the recent development of bioresponsive precursors for the controlled formation of intracellular supramolecular assemblies.

Protease Inhibitors from Plants as Therapeutic Agents- A Review

Plant-based diets are a great source of protease inhibitors (PIs). Two of the most well-known families of PIs are Bowman-Birk inhibitors (BBI) and Kunitz-type inhibitors (KTI). The first group acts mainly on trypsin, chymotrypsin, and elastase; the second is on serine, cysteine, and aspartic proteases. PIs can retard or inhibit the catalytic action of enzymes; therefore, they are considered non-nutritional compounds; nevertheless, animal studies and cell line experiments showed promising results of PIs in treating human illnesses such as obesity, cardiovascular diseases, autoimmune diseases, inflammatory processes, and different types of cancer (gastric, colorectal, breast, and lung cancer). Anticarcinogenic activity's proposed mechanisms of action comprise several inhibitory effects at different molecular levels, i.e., transcription, post-transcription, translation, post-translation, and secretion of cancer cells. This work reviews the potential therapeutic applications of PIs as anticarcinogenic and anti-inflammatory agents in human diseases and the mechanisms by which they exert these effects.

Analysis of trypsin activity at β-casein layers formed on hydrophobic surfaces using a multiharmonic acoustic method

Proteolysis of milk proteins, such as caseins, caused by milk proteases, can change the organoleptic and nutritional characteristics of milk, and therefore it is essential to monitor this enzymatic activity. We used trypsin as a model protease because of its role as a biomarker for pancreatitis. The aim of this work was to demonstrate the detection of proteolysis of β-casein by trypsin using a multiharmonic quartz crystal microbalance (QCM) biosensor. The β-casein layer was deposited from a 0.1 mg mL^-1 solution on a hydrophobic surface consisting of a self-assembled monolayer of 1-dodecanethiol on the gold electrode of the QCM. The addition of an increasing concentration of trypsin leads to the removal of the casein layer due to proteolysis, and correlates with an increase in the resonant frequency of the QCM. We investigated the effect of trypsin concentrations (0.3-20 nM) on the kinetics of the proteolysis of β-casein and demonstrated that the frequency increase is proportional to the protease concentration. Consequently, an inverse Michaelis-Menten model was used to estimate the Michaelis-Menten constant (K_M = 0.38 ± 0.02 nM) and the limit of detection (LOD = 0.16 ± 0.02 nM). The thickness, mass and viscoelastic properties of the protein adlayer after its formation and following the proteolytic cleavage were evaluated by means of multi-harmonic analysis. We found that β-casein is preferably adsorbed on the hydrophobic surfaces as an asymmetrical double layer, of which the innermost layer was found to be denser and thinner (about 2.37 nm) and the outermost layer was found to be less tightly bound and thicker (about 3.5 nm).

Recognition of potential therapeutic role of 2-hydroxy-3-methylanthraquinones in the treatment of gallbladder carcinoma: A proteomics analysis

Gallbladder carcinoma (GBC), with early metastasis and high recurrence rates, is an enormous threat to health. As an anthraquinones monomer of traditional Chinese medicine Hedyotis diffusa, 2-hydroxy-3-methylanthraquinone (HMA) has been reported to inhibit the growth of several cancers. But in our preliminary study, HMA could only weakly induce GBC cell apoptosis. To explore other possible mechanism underlying the inhibition effect of HMA on GBC, this proteomics analysis was performed. A proteomics analysis was performed on one GBC cell line bought from the China Life Science Cell Bank. Several computational techniques were merged to develop analysis for those differently expressed proteins. A comparative protein-protein interaction network analysis was carried out among the differently expressed proteins to identify the proteins potentially inhibiting GBC. Thus, a GO and KEGG analysis was performed to identify the signaling pathways underlying a potential therapeutic role for HMA. A total of 285 proteins were affected by HMA, including 187 upregulated and 98 downregulated. The subcellular localization of differently expressed proteins were identified, including 142 in nuclear, 67 in cytoplasm, 67 in extracellular matrix, 46 in plasma membrane, 13 in mitochondrion, 3 in lysosome, and 1 in cytoskeleton. HMA could regulate EGFR, FN1, PLG, PLAUR, LAMA3, HRG, THBS1, PLAT, KNG1, ENAM, SERPINE1, ECM1, interleukin-8, and trypsin in GBC. Most of the regulated proteins involve in cell migration. Pathways including PI3K-Akt, Wnt, HIF-1, focal adhesion, microRNAs were regulated by HMA. HMA was shown to be an inhibition agent for GBC development, and this analysis would contribute to the development of new anti-GBC drugs.

Role and Merits of Green Based Nanocarriers in Cancer Treatment

Simple Summary

The use of chemotherapy drugs against tumours is associated with various drawbacks such as poor solubility, low stability, high toxicity, lack of selectivity and rapid clearance. Nanocarriers can improve the safety and efficiency of drugs by increasing their solubility, enhance their circulation time and improve their uptake into cancer cells. Natural materials can be incorporated in the fabrication of nanocarriers as a substitute to synthetic ingredients. Several studies developed different types of green based nanocarriers using materials obtained from plant or microbial sources such as polysaccharides and polyphenols without the need of toxic chemicals in the synthesis. The green components can have many roles for example as mechanical support, trigger pH response for drug release, or act as a targeting ligand. The inclusion of these green components will support the cost effective and feasible large-scale production of nanocarriers with minimum negative impact on the environment.

Abstract

The use of nanocarriers for biomedical applications has been gaining interests from researchers worldwide for the delivery of therapeutics in a controlled manner. These “smart” vehicles enhance the dissolution and the bioavailability of drugs and enable their delivery to the target site. Taking the potential toxicity into consideration, the incorporation of natural “green” materials, derived from plants or microbial sources, in the nanocarriers fabrication, improve their safety and biocompatibility. These green components can be used as a mechanical platform or as targeting ligand for the payload or can play a role in the synthesis of nanoparticles. Several studies reported the use of green based nanocarriers for the treatment of diseases such as cancer. This review article provides a critical analysis of the different types of green nanocarriers and their synthesis mechanisms, characterization, and their role in improving drug delivery of anticancer drugs to achieve precision cancer treatment. Current evidence suggests that green-based nanocarriers can constitute an effective treatment against cancer.

Design of Gelatin-Capped Plasmonic-Diatomite Nanoparticles with Enhanced Galunisertib Loading Capacity for Drug Delivery Applications

Inorganic diatomite nanoparticles (DNPs) have gained increasing interest as drug delivery systems due to their porous structure, long half-life, thermal and chemical stability. Gold nanoparticles (AuNPs) provide DNPs with intriguing optical features that can be engineered and optimized for sensing and drug delivery applications. In this work, we combine DNPs with gelatin stabilized AuNPs for the development of an optical platform for Galunisertib delivery. To improve the DNP loading capacity, the hybrid platform is capped with gelatin shells of increasing thicknesses. Here, for the first time, full optical modeling of the hybrid system is proposed to monitor both the gelatin generation, degradation, and consequent Galunisertib release by simple spectroscopic measurements. Indeed, the shell thickness is optically estimated as a function of the polymer concentration by exploiting the localized surface plasmon resonance shifts of AuNPs. We simultaneously prove the enhancement of the drug loading capacity of DNPs and that the theoretical modeling represents an efficient predictive tool to design polymer-coated nanocarriers.

Effect of trypsin concentration on living SMCC-7721 cells studied by atomic force microscopy

Trypsin is playing an important role in the processes of cancer proliferation, invasion and metastasis which require the precise information of morphology and mechanical properties on the nano-scale for the related research. In this work, living human hepatoma (SMCC-7721) cells were treated with different concentrations of trypsin solution. The morphology and mechanical properties of the cells were measured via atomic force microscope (AFM). Statistical analyses of measurement data indicated that with the increase of trypsin concentration, the average cell height and the surface roughness were both increased, but the cell viability, the cell surface adhesion and the elasticity modulus were decreased significantly. The force required to puncture the cells was also gradually reduced. It indicates that trypsin not only hydrolyses the proteins between the cell and the substrate but also the membrane proteins. The results offer valuable clues for the cancerous process study, pathological analysis and trypsin inhibitor drug development. And this work provides an effective way for overcoming the cell membrane in drug injection for cell-targeted therapy.

A Dual-Route Perspective of SARS-CoV-2 Infection: Lung- vs. Gut-specific Effects of ACE-2 Deficiency

SARS-CoV-2, primarily considered a respiratory virus, is increasingly recognized as having gastrointestinal aspects based on its presence in the gastrointestinal (GI) tract and feces. SARS-CoV-2 uses as a receptor angiotensin-converting enzyme 2 (ACE-2), a critical member of the renin-angiotensin-aldosterone system (RAAS) involved in the regulation of blood pressure and fluid system. In addition to the systemic endocrine functions, RAAS components are also involved in intracrine and organ-specific local functions. The angiotensin-converting enzyme 2 (ACE-2) is a key component of RAAS and a receptor for SARS-CoV-2. It is expressed in many tissues with gastrointestinal (GI) tract ACE-2 levels far exceeding those in the respiratory tract. SARS-CoV-2 binding to its receptor results in a deficiency of ACE-2 activity in endocrine, intracrine, and local lung and GI tract ACE-2. The local ACE-2 has different organ-specific functions, including hypertension-independent activities; dysregulations of these functions may contribute to multiorgan COVID-19 pathology, its severity, long-term effects, and mortality. We review supporting evidence from this standpoint. Notably, COVID-19 comorbidities involving hypertension, obesity, heart disease, kidney disease, and diabetes are associated with gastrointestinal problems and display ACE-2 deficits. While RAAS inhibitors target both endocrine and intracrine ACE-2 activity, the deficit of the local ACE-2 activity in the lungs and more so in the gut have not been targeted. Consequently, the therapeutic approach to COVID-19 should be carefully reconsidered. Ongoing clinical trials testing oral probiotic bound ACE-2 delivery are promising.

Tumor-Associated Trypsin Inhibitor (TATI) as a Biomarker of Poor Prognosis in Oropharyngeal Squamous Cell Carcinoma Irrespective of HPV Status

BACKGROUND

We studied the role of tumor-associated trypsin inhibitor (TATI) in serum and in tumor tissues among human papillomavirus (HPV)-positive and HPV-negative OPSCC patients.

MATERIALS AND METHODS

The study cohort included 90 OPSCC patients treated at the Helsinki University Hospital (HUS), Helsinki, Finland, in 2012-2016. TATI serum concentrations (S-TATIs) were determined by an immunofluorometric assay. Immunostaining was used to assess tissue expression. HPV status was determined with a combination of p16 immunohistochemistry and HPV DNA PCR genotyping. The survival endpoints were overall survival (OS) and disease-specific survival (DSS).

RESULTS

A significant correlation was found between S-TATI positivity and poor OS (p < 0.001) and DSS (p = 0.04) in all patients. In HPV-negative cases, S-TATI positivity was linked to poor OS (p = 0.01) and DSS (p = 0.05). In HPV-positive disease, S-TATI positivity correlated with poor DSS (p = 0.01). S-TATI positivity was strongly associated with HPV negativity. TATI serum was negatively linked to a lower cancer stage. TATI expression in peritumoral lymphocytes was associated with favorable OS (p < 0.025) and HPV positivity. TATI expression in tumor and in peritumoral lymphocytes correlated with lower cancer stages.

CONCLUSION

Our results suggest that S-TATI positivity may be a biomarker of poor prognosis in both HPV-positive and HPV-negative OPSCC.

Peptide modified manganese-doped iron oxide nanoparticles as a sensitive fluorescence nanosensor for non-invasive detection of trypsin activity in vitro and in vivo

Herein, a fluorescence turn-on nanosensor (MnIO@pep-FITC) has been proposed for detecting trypsin activity in vitro and in vivo through covalently immobilizing an FITC modified peptide substrate of trypsin (pep-FITC) on manganese-doped iron oxide nanoparticle (MnIO NP) surfaces via a polyethylene glycol (PEG) crosslinker. The conjugation of pep-FITC with MnIO NPs results in the quenching of FITC fluorescence. After trypsin cleavage, the FITC moiety is released from the MnIO NP surface, leading to a remarkable recovery of FITC fluorescence signal. Under the optimum experimental conditions, the recovery ratio of FITC fluorescence intensity is linearly dependent on the trypsin concentration in the range of 2 to 100 ng mL-1 in buffer and intracellular trypsin in the lysate of 5 × 102 to 1 × 104 HCT116 cells per mL, respectively. The detection limit of trypsin is 0.6 ng mL-1 in buffer or 359 cells per mL HCT116 cell lysate. The MnIO@pep-FITC is successfully employed to noninvasively monitor trypsin activity in the ultrasmall (ca. 4.9 mm3 in volume) BALB/c nude mouse-bearing HCT116 tumor by in vivo fluorescence imaging with external magnetic field assistance, demonstrating that it has excellent practicability.

Atractyloside targets cancer-associated fibroblasts and inhibits the metastasis of colon cancer

Background

Several evidences have proved that cancer-associated fibroblasts (CAFs) play a crucial role in tumor progression. In fact, CAFs form a major component of tumor microenvironment (TME). Therefore, the development and metastasis of tumors can be effectively inhibited by small molecular compounds that target CAFs.

Methods

In this study, we mainly analyzed the expression profile of colon cancer (CC). We determined the intensity of CAFs in CC tissues by using the immune cell infiltration score. Gene enrichment analysis and the screening of differentially expressed genes were performed on the basis of the intensity of CAFs in CC tissues. We screened the small molecular compounds that were converted from differentially expressed genes. The results indicated that atractyloside was a small molecular compound related to CAFs in CC tissues. We identified the relationship between atractylosides and CAFs through target protein analysis and network analysis, and verified the inhibition effect of atractylosides on CC cells (CCC) by migration assay and scratch wound-healing assays.

Results

We found that many target proteins of atractyloside, such as the matrix metalloproteinase family and integrin proteins, were related to the biological function of CAFs. By performing network analysis, we found that the target proteins FGF1, ITGB1, and EDNRA were closely related to tumor angiogenesis, while the target proteins MMP9 and ITGAV were correlated to an extracellular matrix (ECM) and cell motility. These findings which further confirmed the relationship between atractylosides and CAFs. In addition, transwell cell migration and scratch wound-healing assays proved that atractylosides could significantly inhibit the migration of CCCs.

Conclusions

The atractyloside might be a small molecular compound that potentially targets CAFs and inhibits the development as well as metastasis of CC by changing the TME.

Novel zwitterionic vectors: Multi-functional delivery systems for therapeutic genes and drugs

Zwitterions consist of equal molar cationic and anionic moieties and thus exhibit overall electroneutrality. Zwitterionic materials include phosphorylcholine, sulfobetaine, carboxybetaine, zwitterionic amino acids/peptides, and other mix-charged zwitterions that could form dense and stable hydration shells through the strong ion-dipole interaction among water molecules and zwitterions. As a result of their remarkable hydration capability and low interfacial energy, zwitterionic materials have become ideal choices for designing therapeutic vectors to prevent undesired biosorption especially nonspecific biomacromolecules during circulation, which was termed antifouling capability. And along with their great biocompatibility, low cytotoxicity, negligible immunogenicity, systematic stability and long circulation time, zwitterionic materials have been widely utilized for the delivery of drugs and therapeutic genes. In this review, we first summarized the possible antifouling mechanism of zwitterions briefly, and separately introduced the features and advantages of each type of zwitterionic materials. Then we highlighted their applications in stimuli-responsive "intelligent" drug delivery systems as well as tumor-targeting carriers and stressed the multifunctional role they played in therapeutic gene delivery.

Development of a Negative-Biased Zwitterionic Polypeptide-Based Nanodrug Vehicle for pH-Triggered Cellular Uptake and Accelerated Drug Release

Albumin mimics could be an attractive platform for nanodrug carriers through systematic administration because of high safety and plentiful properties to be adjusted for a high drug efficacy, such as pH-triggered targeting cellular uptake and drug release. In this work, negative-biased zwitterionic nanodrug carriers based on zwitterionic polypeptide chains that mimic albumin were prepared, which have an outermost layer of zwitterionic glutamic acid (E) and lysine (K) pairs with a small amount of aspartic acid (D) to adjust the overall ζ potential. On the other hand, doxorubicin (Dox) was encapsulated in a hydrophobic core by 11-maleimidoundecanoic acid covalently linked with additional cysteine (C) residues on the polypeptide. The results show that the negative-biased zwitterionic nanodrug carriers can sensitively enhance the cellular uptake in responding to a pH change from 7.4 to 6.7 without reversing the ζ potential to a positive charge, leading to accelerating the Dox release rate in a slightly acidic environment through the polypeptide secondary structure change. Moreover, the anionic nanodrug carrier can also be easily enzymatically digested by trypsin for quick drug release. In short, this negative-biased zwitterionic nanodrug delivery vector could be an ideal candidate for a safer tumor inhibition with a high efficacy than conventional synthetic polymer-based ones.

An Isoform of the Oncogenic Splice Variant AIMP2-DX2 Detected by a Novel Monoclonal Antibody

AIMP2-DX2, an exon 2-deleted splice variant of AIMP2 (aminoacyl-tRNA synthetase-interacting multifunctional protein 2), is highly expressed in lung cancer and involved in tumor progression in vivo. Oncogenic function of AIMP2-DX2 and its correlation with poor prognosis of cancer patients have been well established; however, the application of this potentially important biomarker to cancer research and diagnosis has been hampered by a lack of antibodies specific for the splice variant, possibly due to the poor immunogenicity and/or stability of AIMP2-DX2. In this study a monoclonal antibody, H5, that specifically recognizes AIMP2-DX2 and its isoforms was generated via rabbit immunization and phage display techniques, using a short peptide corresponding to the exon 1/3 junction sequence as an antigen. Furthermore, based on mutagenesis, limited cleavage, and mass spectrometry studies, it is also suggested that the endogenous isoform of AIMP2-DX2 recognized by H5 is produced by proteolytic cleavage of 33 amino acids from N-terminus and is capable of inducing cell proliferation similarly to the uncleaved protein. H5 monoclonal antibody is applicable to enzyme-linked immunosorbent assay, immunoblot, immunofluorescence, and immunohistochemistry, and expected to be a valuable tool for detecting AIMP2-DX2 with high sensitivity and specificity for research and diagnostic purposes.

Reactive oxygen species and enzyme dual-responsive biocompatible drug delivery system for targeted tumor therapy

Spurred by newly developed drug delivery systems (DDSs), side effects of cancer chemotherapy could be reduced by using multifunctional nanoplatforms. However, the facile synthesis of effective DDSs remains a challenge. Here, a six-arginine-tailed anti-epidermal growth factor receptor (EGFR) affibody was employed to easily synthesize the highly reactive oxygen species (hROS)- and trypsin-responsive 11-mercaptoundecanoic acid-modified gold nanoclusters (MUA-Au NCs) for tumor-targeted drug delivery. The polyarginine moiety of affibody sealed methotrexate (MTX)-loaded MUA-Au NCs through charge effect, as well as leaving the rest targeting fragment of the affibody to specifically bind tumor overexpressed EGFR. As the shell of MUA-Au NCs-MTX-Affibody (MAMA), polyarginine chains of affibody could be digested by trypsin, helping to release MTX from MAMA. The released MTX accelerated destroying MUA-Au NCs through inducing the generation of hROS. Specifically targeting EGFR-overexpressed tumors, quickly delivering a sufficient amount of drug to the tumor, subsequently increasing the local MTX and hROS levels, and safely eliminating the biocompatible structure from kidney, endowed MAMA greater treatment effectiveness and lower side effect than chemotherapy, especially in pancreatic cancer due to its high trypsin level. This simply fabricated DDS may find applications in high effective cancer therapy, especially for tumors with high trypsin activity.

Optical assay of trypsin using a one-dimensional plasmonic grating of gelatin-modified poly(methacrylic acid)

The geometry of resonant absorbers (RA) is varied by tryptic digestion to design a probe platform. The process includes fabrication of a line array of poly(methacrylic acid) (PMAA) brush as an RA, tailed by the immobilization of gelatin. The gelatin-modified PMAA RA is a kind of one-dimensional plasmonic grating, possessing an optical feature with a characteristic absorption peak. The growth of gelatin on PMAA RA resulted in a blue shift of the absorption peak from 465 to 263 nm. Trypsin catalyzes the hydrolysis of peptide bonds, breaking down gelatin into smaller peptides causing the change in geometry of RA. The gelatin of RA was digested in a wide linear range of activity of trypsin from 34 to 1088 U mL^-1 resulting in a red shift of the absorption peak of RA from 263 to 474 nm within 10 min. The limit of detection achieved is 11 U mL^-1 with ca. 1.9% standard deviation and 101.4% recovery of spiked serum samples. The chemical selectivity of the trypsin assay is evidenced by motoring the changes in a shift of the absorption peak of gelatin-modified PMAA RA using chymotrypsin and horseradish peroxidase. Graphical abstract Schematic representation of synthesis route of 1D gelatin grating on silicon surface for trypsin probing.

Remote biosensor for the determination of trypsin by using nanoporous anodic alumina as a three-dimensional nanostructured material

The determination of trypsin in the human real sample is a routine medical investigation to assess the pancreatic disease. Herein, we fabricated an interferometric reflectance spectroscopy based biosensor for the determination trypsin. For this purpose, urease and fluorescein 5(6)-isothiocyanate (FLITC) were immobilized on the nanoporous anodic alumina (NAA). The operation principle of the proposed biosensor is based on the change in the pH of the solution during the reaction of urease and urea and therefore change in the light-absorbing ability of FLITC in the presence of trypsin. The reaction of the urease enzyme with urea increased the pH of the solution because of producing ammonia. This increase in the pH of solution increased the light-absorbing ability of the immobilized FLITC on NAA and therefore the intensity of the reflected light from the NAA to the charge-coupled device detector decreased. In the presence of trypsin, the catalytic activity of immobilized urease on NAA decreased. This decrease in the activity of urease enzyme consequent on the decrease in the amount of the generated ammonia. Therefore, the immobilized FLITC on the NAA did not absorb more light and consciously, the intensity of the light reflected light into the detector increased. The proposed biosensor exhibited a good response to the concentration of trypsin in the range of 0.25–20 μg.mL⁻¹ with the limit of detection of 0.06 μg.mL⁻¹.

Is There a Trojan Horse to Aggressive Pancreatic Cancer Biology? A Review of the Trypsin-PAR2 Axis to Proliferation, Early Invasion, and Metastasis

Purpose: Pancreatic cancer is one of the most lethal of solid tumors and is associated with aggressive cancer biology. The purpose is to review the role of trypsin and effect on molecular and cellular processes potentially explaining the aggressive biology in pancreatic cancer.

Methods: A narrative literature review of studies investigating trypsin and its effect on protease systems in cancer, with special reference to pancreatic cancer biology.

Results: Proteases, such as trypsin, provides a significant advantage to developing tumors through the ability to remodel the extracellular matrix, promote cell invasion and migration, and facilitate angiogenesis. Trypsin is a digestive enzyme produced by the exocrine pancreas that is also related to mechanisms of proliferation, invasion and metastasis. Several of these mechanisms may be co-regulated or influenced by activation of proteinase-activated receptor 2 (PAR-2). The current role in pancreatic cancer is not clear but emerging data suggest several potential mechanisms. Trypsin may act as a Trojan horse in the pancreatic gland, facilitating several molecular pathways from the onset, which leads to rapid progression of the disease. Pancreatic cancer cell lines containing PAR-2 proliferate upon exposure to trypsin, whereas cancer cell lines not containing PAR-2 fail to proliferate upon trypsin expression. Several mechanisms of action include a proinflammatory environment, signals inducing proliferation and migration, and direct and indirect evidence for mechanisms promoting invasion and metastasis. Novel techniques (such as organoid models) and increased understanding of mechanisms (such as the microbiome) may yield improved understanding into the role of trypsin in pancreatic carcinogenesis.

Conclusion: Trypsin is naturally present in the pancreatic gland and may experience pathological activation intracellularly and in the neoplastic environment, which speeds up molecular mechanisms of proliferation, invasion, and metastasis. Further investigation of these processes will provide important insights into how pancreatic cancer evolves, and suggest new ways for treatment.

A novel peptide-based electrochemical biosensor for the determination of a metastasis-linked protease in pancreatic cancer cells

Proteases are involved in cancer' taking part in immune (dis)regulation, malignant progression and tumour growth. Recently, it has been found that expression levels of one of the members of the serine protease family, trypsin, is upregulated in human cancer cells of several organs, being considered as a specific cancer biomarker. Considering the great attention that electrochemical peptide sensors have nowadays, in this work, we propose a novel electroanalytical strategy for the determination of this important biomolecule. It implies the immobilization of a short synthetic peptide sequence, dually labelled with fluorescein isothiocyanate (FITC) and biotin, onto neutravidin-modified magnetic beads (MBs), followed by the peptide digestion with trypsin. Upon peptide disruption, the modified MBs were incubated with a specific fluorescein Fab fragment antibody labelled with horseradish peroxidase (HRP-antiFITC) and magnetically captured on the surface of a screen-printed carbon electrode (SPCE), where amperometric detection was performed using the hydroquinone (HQ)/HRP/H₂O₂ system. The biosensor exhibited a good reproducibility of the measurements (RSD 3.4%, n = 10), and specificity against other proteins and proteases commonly found in biological samples. This work reports the first quantitative data so far on trypsin expression in human cell lysates. The developed bioplatform was used for the direct determination of this protease in lysates from pancreatic cancer, cervix carcinoma and kidney cells in only 3 h and 30 min using low amounts (~ 0.1 μg) of raw extracts. Graphical abstract.

Synthesis and evaluation of anticancer, antiphospholipases, antiproteases, and antimetabolic syndrome activities of some 3H-quinazolin-4-one derivatives

Some new 3H-quinazolin-4-one derivatives were synthesised and screened for anticancer, antiphospholipases, antiproteases, and antimetabolic syndrome activities. Compound 15d was more potent in reducing the cell viabilities of HT-29 and SW620 cells lines to 38%, 36.7%, compared to 5-FU which demonstrated cell viabilities of 65.9 and 42.7% respectively. The IC50 values of 15d were ∼20 µg/ml. Assessment of apoptotic activity revealed that 15d decreased the cell viability by down regulating Bcl2 and BclxL. Moreover, compounds, 8j, 8d/15a/15e, 5b, and 8f displayed lowered IC50 values than oleanolic acid against proinflammatory isoforms of hGV, hG-X, NmPLA2, and AmPLA2. In addition, 8d, 8h, 8j, 15a, 15b, 15e, and 15f showed better anti-α-amylase than quercetin, whereas 8g, 8h, and 8i showed higher anti-α-glucosidase activity than allopurinol. Thus, these compounds can be considered as potential antidiabetic agents. Finally, none of the compounds showed higher antiproteases or xanthine oxidase activities than the used reference drugs.

Self-Assembly and Enzyme Responsiveness of Amphiphilic Linear-Dendritic Block Copolymers Based on Poly(N-vinylpyrrolidone) and Dendritic Phenylalanyl-lysine Dipeptides

In this study, we present the synthesis, self-assembly, and enzyme responsive nature of a unique class of well-defined amphiphilic linear-dendritic block copolymers (PNVP-b-dendr(Phe-Lys)n, n = 1-3) based on linear poly(N-vinylpyrrolidone) (PNVP) and dendritic phenylalanyl-lysine (Phe-Lys) dipeptides. The copolymers were prepared via a combination ofreversible addition-fragmentation chain transfer (RAFT) /xanthates (MADIX) polymerization of N-vinylpyrrolidone and stepwise peptide chemistry. The results of fluorescence spectroscopy, 1H NMR analyses, transmission electron microscopy (TEM), and particle size analysis demonstrated that the copolymers self-assemble in aqueous solution into micellar nanocontainers that can disassemble and release encapsulated anticancer drug doxorubicin or hydrophobic dye Nile red by trigger of a serine protease trypsin under physiological conditions. The disassembly of the formed micelles and release rates of the drug or dye can be adjusted by changing the generation of dendrons in PNVP-b-dendr(Phe-Lys)n. Furthermore, the cytocompatibility of the copolymers have been confirmed using human lung epithelial cells (BEAS-2B) and human liver cancer cells (SMMC-7721). Due to the fact of their enzyme responsive properties and good biocompatibility, the copolymers may have potential applicability in smart controlled release systems capable of site-specific response.

Protease-activated receptor signaling in intestinal permeability regulation

Protease-activated receptors (PARs) are a unique class of G-protein-coupled transmembrane receptors, which revolutionized the perception of proteases from degradative enzymes to context-specific signaling factors. Although PARs are traditionally known to affect several vascular responses, recent investigations have started to pinpoint the functional role of PAR signaling in the gastrointestinal (GI) tract. This organ is exposed to the highest number of proteases, either from the gut lumen or from the mucosa. Luminal proteases include the host's digestive enzymes and the proteases released by the commensal microbiota, while mucosal proteases entail extravascular clotting factors and the enzymes released from resident and infiltrating immune cells. Active proteases and, in case of a disrupted gut barrier, even entire microorganisms are capable to translocate the intestinal epithelium, particularly under inflammatory conditions. Especially PAR-1 and PAR-2, expressed throughout the GI tract, impact gut permeability regulation, a major factor affecting intestinal physiology and metabolic inflammation. In addition, PARs are critically involved in the onset of inflammatory bowel diseases, irritable bowel syndrome, and tumor progression. Due to the number of proteases involved and the multiple cell types affected, selective regulation of intestinal PARs represents an interesting therapeutic strategy. The analysis of tissue/cell-specific knockout animal models will be of crucial importance to unravel the intrinsic complexity of this signaling network. Here, we provide an overview on the implication of PARs in intestinal permeability regulation under physiologic and disease conditions.

PRSS1 mutation: a possible pathomechanism of pancreatic carcinogenesis and pancreatic cancer

Background

Previous studies revealed somatic mutations of the cationic trypsinogen gene (PRSS1) in patients with chronic pancreatitis and pancreatic cancer. However, whether PRSS1 mutations trigger pancreatic cancer and/or promote malignant proliferation and metastasis in pancreatic cancer remains largely unclear, as well as the potential underlying mechanisms.

Methods

In the present study, whole-exome sequencing was applied for screening, and the R116C mutation was validated by Sanger sequencing. Phosphorylation antibody array, RNA-Seq, and RT-qPCR were adopted to screen and validate that R116C mutation promoted pancreatic cancer progression via the JAK1-STAT5 pathway.

Results

It showed that migration and invasion were significantly increased in R116C-bearing PANC-1 cells compared with wild type counterparts. In a transgenic mouse model of iZEG-PRSS1_R116C, primary pancreatic intraepithelial neoplasia (PanINs) was observed in the pancreatic duct.

Conclusions

These findings suggested a novel pathway mediating pancreatic cancer development, with PRSS1 mutation and overexpression playing an “inside job” role in pancreatic carcinogenesis and tumor development.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s10020-019-0111-4.