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1.
R Soc Open Sci ; 11(7): 240347, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39086820

ABSTRACT

This work presents a new framework for a competitive evolutionary game between monoclonal antibodies and signalling pathways in oesophageal cancer. The framework is based on a novel dynamical model that takes into account the dynamic progression of signalling pathways, resistance mechanisms and monoclonal antibody therapies. This game involves a scenario in which signalling pathways and monoclonal antibodies are the players competing against each other, where monoclonal antibodies use Brentuximab and Pembrolizumab dosages as strategies to counter the evolutionary resistance strategy implemented by the signalling pathways. Their interactions are described by the dynamical model, which serves as the game's playground. The analysis and computation of two game-theoretic strategies, Stackelberg and Nash equilibria, are conducted within this framework to ascertain the most favourable outcome for the patient. By comparing Stackelberg equilibria with Nash equilibria, numerical experiments show that the Stackelberg equilibria are superior for treating signalling pathways and are critical for the success of monoclonal antibodies in improving oesophageal cancer patient outcomes.

2.
J Control Release ; 2024 Jul 31.
Article in English | MEDLINE | ID: mdl-39094631

ABSTRACT

Despite significant progress in combining cancer immunotherapy with chemotherapy to treat triple negative breast cancer (TNBC), challenges persist due to target depletion and tumor heterogeneity, especially in metastasis. Chemotherapy lacks precise targeting abilities, and targeted therapy is inadequate in addressing the diverse heterogeneity of tumors. To address these challenges, we introduce RGDEVD-DOX as a tumor-specific immunogenic agent, namely TPD1, which targets integrin αvß3 and gets continuously activated by apoptosis. TPD1 facilitates the caspase-3-mediated in situ amplification that results in tumor-specific accumulation of doxorubicin. This local concentration of doxorubicin induces immunogenic cell death and promotes the recruitment of immune cells to the tumor site. Notably, the tumor-targeting capabilities of TPD1 help bypass the systemic immunotoxicity of doxorubicin. Consequently, this alters the tumor microenvironment, converting it into a 'hot' tumor that is more susceptible to immune checkpoint inhibition. We demonstrated the anti-metastatic and anti-cancer efficacy of this treatment using various xenograft and metastatic models. This study underscores the high potential of caspase-3 cleavable peptide-drug conjugates to be used in conjunction with anti-cancer immunotherapies.

3.
Exp Mol Pathol ; 139: 104922, 2024 Aug 02.
Article in English | MEDLINE | ID: mdl-39096891

ABSTRACT

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the alimentary tract. The prognosis depends on the primary site, and small intestinal GISTs have a worse prognosis than gastric GISTs. Molecularly targeted drugs to inhibit tyrosine kinase activity of KIT were used for unresectable or recurrent GISTs. However, secondary resistance to the drugs is often acquired, and treatments based on other mechanisms are needed. Previously, we reported that cell adhesion molecule 1 (CADM1) was highly expressed in most of small intestinal GISTs but not in most of gastric GISTs. In the present study, we examined whether the antibody-drug conjugate (ADC) with anti-CADM1 antibody and monomethyl auristatin E (anti-CAD-ADC) shows anti-tumor effect on CADM1-expressing human GIST cells. The ADC adhibited in this study was previously used for CADM1-expressing human mesothelioma cells and showed anti-tumor effect for them in vitro. GIST-T1 cell line of gastric origin which scarcely expresses CADM1 and GIST-T1 cells transfected with CADM1 cDNA (GIST-T1-CAD cells) which highly expresses CADM1 and represents small intestinal GIST were used. In vitro, anti-CAD-ADC showed remarkable cytotoxic activity on GIST-T1-CAD cells, but control ADC did not. Both anti-CAD-ADC and control ADC did not show anti-tumor effect on original GIST-T1 cells. When GIST-T1-CAD cells were subcutaneously injected to the nude mice, intravenous administration of anti-CAD-ADC showed inhibitory effect for tumor enlargement. Tumor of GIST-T1 cells grew even after anti-CAD-ADC injection. When GIST-T1-CAD cells were injected into peritoneal cavity of the SCID mice, intraperitoneal administration of anti-CAD-ADC showed reduction of the peritoneal tumor. On the other hand, peritoneal tumor grew after control ADC administration. Tissue and organ damage due to administration of anti-CAD-ADC was not apparent by macroscopic and histological examinations in mice. These results indicate that anti-CAD-ADC could have apparent anti-tumor effect on CADM1-expressing human GIST cells both in in vitro and in vivo mouse models.

4.
Article in English | MEDLINE | ID: mdl-39109479

ABSTRACT

Polymer-drug conjugates and polymer-protein conjugates have been pivotal in the realm of drug delivery systems for over half a century. These polymeric drugs are characterized by the conjugation of therapeutic molecules or functional moieties to polymers, enabling a range of benefits including extended circulation times, targeted delivery, controlled release, and decreased immunogenicity. This review delves into recent advancements and challenges in the clinical translations and preclinical studies of polymer-drug conjugates and polymer-protein conjugates. The design principles and functionalization strategies crucial for the development of these polymeric drugs were explored followed by the review of structural properties and characteristics of various polymer carriers. This review also identifies significant obstacles in the clinical translation of polymer-drug conjugates and provides insights into the directions for their future development. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.


Subject(s)
Drug Carriers , Drug Delivery Systems , Polymers , Proteins , Humans , Polymers/chemistry , Proteins/chemistry , Animals , Drug Carriers/chemistry , Drug Design , Nanoparticles/chemistry , Nanomedicine
5.
Sci Rep ; 14(1): 17808, 2024 08 01.
Article in English | MEDLINE | ID: mdl-39090195

ABSTRACT

Antimicrobial peptides, such as nisin, are proposed as promising agents for cancer treatment. While glycation has been recognized as an effective method for enhancing various physicochemical properties of nisin, its anticancer effects remain unexplored. Therefore, we aimed to assess the anticancer potential of glycated nisin against MDA-MB-231 cells. The MDA-MB cells were treated with increasing concentrations of nisin and glycated nisin for 24, 48, and 72 h. The IC50 values for nisin were higher than those for glycated nisin. Glycated nisin at concentrations of 20 and 40 µg/mL decreased cell viability more than nisin at the same concentrations. The rate of apoptosis in the group treated with 20 µg/mL of nisin was lower compared to other treatment groups, and no significant difference in apoptosis rates was observed at different time points (p > 0.05). However, in the glycated nisin groups with concentrations of 10, 20, and 40 µg/mL, the level of apoptosis was very high after 24 h (73-81% of cells undergoing apoptosis). Overall, our study suggests that glycated nisin exhibits stronger cytotoxic effects on MDA-MB-231 cells, primarily involving the induction of apoptosis. This indicates its potential utilization as an alternative approach to address the issue of drug resistance in cancer cells.


Subject(s)
Apoptosis , Breast Neoplasms , Cell Survival , Nisin , Nisin/pharmacology , Humans , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Breast Neoplasms/metabolism , Apoptosis/drug effects , Cell Line, Tumor , Glycosylation/drug effects , Cell Survival/drug effects , Female , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry
6.
ESMO Open ; 9(9): 103679, 2024 Aug 22.
Article in English | MEDLINE | ID: mdl-39178538

ABSTRACT

Therapeutic developments in the targeting of human epidermal growth factor receptor 2 (HER2)-expressing gastric cancer have followed the dramatic success of HER2-expressing breast cancer treatment, which has facilitated the expansion of indications for anti-HER2 agents to include not only conventional HER2-positive breast cancer, but also HER2-low and HER2-ultralow subgroups. The targetability of HER2-low gastric cancer, however, has yet to be established. Hence, further studies are needed to comprehensively understand the clinicopathological features, specific gene alterations, and distinct tumor immune microenvironment of HER2-low gastric cancer and compare them with those for HER2-positive or -negative gastric cancer. Antibody-drug conjugates for HER2 play an important role in making HER2-low gastric cancer targetable. In this context, a deeper understanding of the novel anti-HER2 agents, including antibody-drug conjugates, bispecific T-cell engager antibodies, and a combination of these agents, as well as new forms of immunomodulatory agents are also required. Redefining and re-categorizing HER2 status through not only immunohistochemistry/fluorescence in situ hybridization but also evaluating ERRB2 copy number gain or protein overexpression levels measured using DNA or RNA sequencing might be helpful for identifying populations with HER2-expressing tumors who would ideally benefit from anti-HER2 treatment. The current paper reviewed recent clinical trials, focusing particularly on HER2-low gastric cancer together with basic/translational findings, and discuss perspectives on further therapeutic development in the treatment of this distinct subgroup.

7.
Front Oncol ; 14: 1378248, 2024.
Article in English | MEDLINE | ID: mdl-39188688

ABSTRACT

Sacituzumab govitecan (SG), a Trop-2-directed antibody-drug conjugate (ADC), was the first ADC approved for patients with metastatic triple-negative breast cancer (mTNBC) who had received at least two prior lines of therapy for advanced disease. Although SG has shown promising clinical activity in treating brain metastases in both ASCENT randomized trials and real-world analysis, its utility in leptomeningeal carcinomatosis (LC) remains underexplored. We report the diagnostic and therapeutic process of a patient who develops extensive LC from TNBC treated with SG. She presented a clinical response after the first cycle of SG with a PFS of 6 months. This case report highlights the need for further inquiry into the use of SG in LC.

8.
Expert Opin Pharmacother ; : 1-13, 2024 Aug 27.
Article in English | MEDLINE | ID: mdl-39164924

ABSTRACT

INTRODUCTION: Cervical cancer, while highly preventable, remains an international public health challenge especially in under resourced regions. Although early-stage cervix confined cancers are often amenable to surgical resection, larger tumors deemed locally advanced cervical cancer (LACC) necessitate systemic therapy as part of chemoradiation therapy. Moreover, systemic therapy is the standard therapeutic approach for those presenting with primary metastasis or recurrence. AREAS COVERED: While several agents have been approved to treat recurrent cervical cancer including checkpoint inhibitors as well as both biomarker agnostic and specific antibody drug conjugates, the development of agents added to chemoradiation has been less fruitful. Until recently, the addition of novel therapies to chemoradiation has been negative in terms of improving outcomes; however, results of a recent Phase III clinical trial (NCT04221945) in LACC demonstrated that the addition of pembrolizumab to standard of care chemoradiation was associated with an improvement in progression-free survival and resulted in an FDA approval for this therapy. This observation led to the first change in treating LACC since the early 2000s. EXPERT OPINION: Improvements in systemic therapy both alone and in combination with chemoradiation for cervical cancer have been realized. Ongoing research is needed for therapeutic options following immunotherapy.

9.
Int J Pharm ; : 124621, 2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39182745

ABSTRACT

Conjugation of a therapeutic agent to a polymer for enhanced delivery into target cells followed by its intracellular triggered release has proved to be an effective drug delivery approach. This approach is applied to the delivery of the immune-stimulatory unmethylated cytosine-phosphate-guanine (CpG) oligonucleotide for an anti-tumour immune response after intratumoral administration. On average four CpG-1668 molecules were covalently linked to a 40-kDa amino-functionalised dextran polymer via either a non-reversible (CpG-dextran) or an intracellular redox-responsive disulfide linkage (CpG-SS-dextran). Dynamic light scattering analysis showed that both conjugates had a similar particle size and surface charge of 17 nm and -10 mV, respectively. Agarose gel electrophoresis analysis showed that CpG-SS-dextran was stable in the extracellular low glutathione (GSH) concentration range (i.e. 10-20 µM) and was cleaved at the higher intracellular GSH concentration (5 mM), while CpG-dextran was stable in both GSH concentrations. Uptake and activation assays on bone-marrow-derived dendritic cells showed no significant difference between free CpG, CpG-dextran and CpG-SS-dextran. In a mouse subcutaneous colorectal tumour model the CpG-SS-dextran showed a statistically significantly greater inhibition of tumour growth (p < 0.03) and prolonged survival (p < 0.001) compared to CpG-dextran or free CpG. These results demonstrate that the redox-triggered intracellular release of CpG from a dextran polymer carrier has promise for intratumoral therapeutic vaccination against cancer.

10.
Int J Biol Macromol ; : 135061, 2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39182866

ABSTRACT

This study aimed to investigate the impact of polysaccharide type on the physicochemical, structural, and thermal properties of dielectric barrier discharge (DBD) plasma glycosylated sodium caseinate (SC). The polysaccharides Quince seed gum (QSG), carboxymethyl cellulose (CMC), and maltodextrin (MD) were mixed with SC and treated with DBD plasma at 18 kV for 10 min. The grafting degree, electrophoresis pattern, FTIR, XRD, carbonyl, sulfhydryl, and di-tyrosine content, FE-SEM, color, and thermal properties of SC and its polysaccharide mixtures before and after plasma treatment were analyzed. Results showed that the SC-QSG conjugate had the highest glycation degree and color change after plasma treatment. The SC-CMC and SC-QSG conjugates exhibited disappearance of distinct SC bands in electrophoresis pattern compared to SC. Also, significant changes in functional group and crystallinity were occurred in SC-CMC conjugate. Plasma treatment caused oxidation of SC, but the presence of polysaccharides offered protection against oxidation. The microstructure of SC was altered by mixing with polysaccharides and exposure to plasma. Also, the mixtures indicates higher thermal stability after plasma treatment. Results confirmed that the generation of protein-polysaccharide conjugates through DBD plasma technique was depended on with SC-MD conjugate unable to form through this method.

11.
Environ Sci Technol ; 2024 Aug 13.
Article in English | MEDLINE | ID: mdl-39137285

ABSTRACT

The consumption of disposable surgical masks (DSMs) considerably increased during the coronavirus pandemic in 2019. Herein, we explored the spread of antibiotic resistance genes (ARGs) and the potential risks of antibiotic resistant bacteria (ARB) on DSMs. At environmentally relevant concentrations, the conjugate transfer frequency (CTF) of ARGs increased by 1.34-2.37 folds by 20 µg/m3 of atmospheric water-soluble inorganic ions (WSIIs), and it increased by 2.62-2.86 folds by 80 ng/m3 of polycyclic aromatic hydrocarbons (PAHs). Total suspended particulates (TSP) further promoted the CTF in combination with WSIIs or PAHs. Under WSII and PAH exposure, gene expression levels related to oxidative stress, cell membrane, and the adenosine triphosphate (ATP) were upregulated. WSIIs predominantly induced cellular contact, while PAHs triggered ATP formation and membrane damage. Molecular dynamics simulations showed that WSIIs and PAHs reduced membrane lipid fluidity and increased membrane permeability through interactions with the phosphatidylcholine bilayer. DSM filtering performance decreased, and the CTF of ARGs increased with the wearing time. The gut simulator test showed that ARB disrupted the human gut microbial community and increased total ARG abundance but did not change the ARG abundance carried by ARB themselves. A mathematical model showed that long-term WSII and PAH exposure accelerated ARG dissemination in DSMs.

12.
Biologicals ; 87: 101785, 2024 Aug 08.
Article in English | MEDLINE | ID: mdl-39121525

ABSTRACT

Diagnostic assays that are able to detect foot-and-mouth disease (FMD) virus infection in the vaccinated population are essential tools in the progressive control pathway for the FMD. However, testing of serum samples using a single diagnostic assay may not completely substantiate freedom from the virus infection. Therefore, viral non-structural proteins (NSPs)-based various serological assays have been developed for the detection of FMD infection. Nevertheless, the NSPs-based ELISAs have been developed in the indirect-ELISA format, thereby necessitating the use of species-specific conjugated secondary-antibodies for the detection of anti-NSP antibodies in various FMD-susceptible species. Therefore, this study presents a novel recombinant 2B-NSP-based indirect ELISA, employing HRP-conjugated protein-A/G detection system which can detect anti-NSPs antibodies from multiple FMD-susceptible species in a single ELISA platform. Recombinant 2B (r2B) protein was expressed as His-SUMO tagged protein in the E. Coli cells and purified using NI-NTA affinity column chromatography. Using the r2B protein and HRP-conjugated protein A/G, an indirect ELISA was developed and validated for the detection of anti-2B antibodies in serum samples collected from multiple FMD-susceptible animal species with known FMD status. Further, a resampling based statistical technique has been reported for determination of optimal cut-off value for the diagnostic assay. Through this technique, the optimal cut-off of 44 percentage of positivity value was determined for the assay. At this optimal cut-off value, the developed diagnostic assay provided diagnostic sensitivity, specificity, and accuracy, positive and negative predictive values (PPV and NPV) of 92.35 %, 98.41 %, 95.21 %, 98.58 %, and 91.67 %, respectively. The assay was validated further by analyzing random serum samples collected across multi-locations in India. The assay can be used as a single platform for testing serum samples from different species of FMDV-susceptible animals and will be useful for NSP-based serosurveillance of FMDV.

13.
J Pharm Pharm Sci ; 27: 12921, 2024.
Article in English | MEDLINE | ID: mdl-39114808

ABSTRACT

Chitosan is an extensively used polymer for drug delivery applications in particulate and non-particulate carriers. Chitosan-based particulate, nano-, and microparticle, carriers have been the most extensively studied for the delivery of therapeutics and vaccines. However, chitosan has also been used in vaccine applications for its adjuvant properties in various hydrogels or as a carrier coating material. The focus of this review will be on the usage of chitosan as a vaccine adjuvant based on its intrinsic immunogenicity; the various forms of chitosan-based non-particulate delivery systems such as thermosensitive hydrogels, microneedles, and conjugates; and the advantages of its role as a coating material for vaccine carriers.


Subject(s)
Chitosan , Drug Delivery Systems , Vaccines , Chitosan/chemistry , Humans , Vaccines/administration & dosage , Vaccines/chemistry , Animals , Hydrogels/chemistry , Hydrogels/administration & dosage , Drug Carriers/chemistry
14.
Cancer ; 130(S17): 3054-3066, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-39092590

ABSTRACT

Antibody-drug conjugates (ADCs) have demonstrated effectiveness in treating various cancers, particularly exhibiting specificity in targeting human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Recent advancements in phase 3 clinical trials have broadened current understanding of ADCs, especially trastuzumab deruxtecan, in treating other HER2-expressing malignancies. This expansion of knowledge has led to the US Food and Drug Administration's approval of trastuzumab deruxtecan for HER2-positive and HER2-low breast cancer, HER2-positive gastric cancer, and HER2-mutant nonsmall cell lung cancer. Concurrent with the increasing use of ADCs in oncology, there is growing concern among health care professionals regarding the rise in the incidence of interstitial lung disease or pneumonitis (ILD/p), which is associated with anti-HER2 ADC therapy. Studies on anti-HER2 ADCs have reported varying ILD/p mortality rates. Consequently, it is crucial to establish guidelines for the diagnosis and management of ILD/p in patients receiving anti-HER2 ADC therapy. To this end, a panel of Chinese experts was convened to formulate a strategic approach for the identification and management of ILD/p in patients treated with anti-HER2 ADC therapy. This report presents the expert panel's opinions and recommendations, which are intended to guide the management of ILD/p induced by anti-HER2 ADC therapy in clinical practice.


Subject(s)
Immunoconjugates , Lung Diseases, Interstitial , Receptor, ErbB-2 , Humans , Lung Diseases, Interstitial/drug therapy , Lung Diseases, Interstitial/chemically induced , China , Immunoconjugates/therapeutic use , Immunoconjugates/adverse effects , Pneumonia/drug therapy , Female , Consensus , Trastuzumab/therapeutic use , Trastuzumab/adverse effects , Breast Neoplasms/drug therapy , Camptothecin/analogs & derivatives
15.
ChemMedChem ; : e202300481, 2024 Aug 13.
Article in English | MEDLINE | ID: mdl-39136598

ABSTRACT

Daunorubicin and doxorubicin are among the most potent anti-cancer drugs and bind to DNA through intercalation. In this paper, we demonstrate that formaldehyde can efficiently and specifically conjugate daunorubicin and doxorubicin to GTP, resulting in the formation of daunorubicin-GTP-1 and doxorubicin-GTP-1 conjugates. The linkage occurs between the 2-NH2 of guanine and the 3'-NH2 of daunosamine. We characterized these daunorubicin/doxorubicin-GTP conjugates using various methods, including UV-Vis, fluorescence, CD, FT-IR, and mass spectrometry. Our results also indicate that these daunorubicin/doxorubicin-GTP conjugates bind to DNA via intercalation. Furthermore, we observed rapid accumulation of these conjugates in human cancer cells and observed cytotoxic effects in both doxorubicin-sensitive SK-OV-3 and doxorubicin-resistant NCI/ADR-RES cells, suggesting that these daunorubicin and doxorubicin derivatives can overcome doxorubicin resistance.

16.
Front Oncol ; 14: 1419145, 2024.
Article in English | MEDLINE | ID: mdl-39161379

ABSTRACT

This case report describes a 16-year-old patient with refractory Hodgkin's lymphoma who developed bilateral anterior and intermediate uveitis as an adverse reaction to Brentuximab vedotin (BV). This is a rare case of an ocular adverse reaction potentially related to BV, with symptoms like blurred vision, decreased visual acuity, photophobia, and redness. Potential mechanisms include BV targeting CD30+ T cells in the uveal tissue or an immune response triggered by the microtubule-disrupting agent MMAE within BV. This highlights the need for vigilant monitoring of ocular adverse events in BV-treated patients and further research into their mechanisms and management.

17.
Biomark Res ; 12(1): 82, 2024 Aug 13.
Article in English | MEDLINE | ID: mdl-39135109

ABSTRACT

Human trophoblastic cell surface antigen 2 (Trop2) is a glycoprotein, a cellular marker of trophoblastic and stem cells, and a calcium signaling transducer involved in several signaling pathways, leading to the proliferation, invasion, and metastasis of tumors. It is expressed at a low level in normal epithelial cells, but at a high level in many tumors, making it an ideal target for cancer therapy. According to previous literature, Trop2 is broadly expressed in all breast cancer subtypes, especially in triple negative breast cancer (TNBC). Several clinical trials have demonstrated the effectiveness of Trop2-targeted therapy in breast cancer. Sacituzumab govitecan (SG) is a Trop2-targeted antibody-drug conjugate (ADC) that has been approved for the treatment of metastatic TNBC and hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer. This article reviews the structure and function of Trop2, several major Trop2-targeted ADCs, other appealing novel Trop2-targeted agents and relevant clinical trials to provide a landscape of how Trop2-targeted treatments will develop in the future.

18.
J Leukoc Biol ; 2024 Aug 14.
Article in English | MEDLINE | ID: mdl-39141715

ABSTRACT

Vaccine-mediated protection and susceptibility to Streptococcus pneumoniae (pneumococcus) infections are influenced by biological sex. The incidence of invasive pneumococcal disease remains higher in males compared to females even after the introduction of the pneumococcal conjugate vaccine (PCV). However, sex-based differences in the immune response to this conjugate vaccine remain unexplored. To investigate those differences, we vaccinated adult male and female mice with PCV and assessed cellular and humoral immune responses. Compared to females, male mice displayed lower levels of T follicular helper cells, germinal center B cells and plasmablasts, which are all required for antibody production following vaccination. This was linked to lower IgG and IgM levels against pneumococci and lower isotype switching to IgG3 in vaccinated males. Due to lower antibody levels, sera of vaccinated male mice had lower efficacy in several anti-pneumococcal functions including neutralization of bacterial binding to pulmonary epithelial cells as well as direct cytotoxicity against S. pneumoniae. Importantly, while the vaccine was highly protective in females, vaccinated males succumbed to infection more readily and were more susceptible to both lung-localized infection and systemic spread following S. pneumoniae challenge. These findings identify sex-based differences in immune responses to PCV that can inform future vaccine strategies.

19.
Neural Netw ; 179: 106599, 2024 Aug 06.
Article in English | MEDLINE | ID: mdl-39142176

ABSTRACT

Dealing with high-dimensional problems has always been a key and challenging issue in the field of fuzzy systems. Traditional Takagi-Sugeno-Kang (TSK) fuzzy systems face the challenges of the curse of dimensionality and computational complexity when applied to high-dimensional data. To overcome these challenges, this paper proposes a novel approach for optimizing TSK fuzzy systems by integrating the spectral Dai-Yuan conjugate gradient (SDYCG) algorithm and the smoothing group L0 regularization technique. This method aims to address the challenges faced by TSK fuzzy systems in handling high-dimensional problems. The smoothing group L0 regularization technique is employed to introduce sparsity, select relevant features, and improve the generalization ability of the model. The SDYCG algorithm effectively accelerates convergence and enhances the learning performance of the network. Furthermore, we prove the weak convergence and strong convergence of the new algorithm under the strong Wolfe criterion, which means that the gradient norm of the error function with respect to the weight vector converges to zero, and the weight sequence approaches a fixed point.

20.
Methods Enzymol ; 702: 21-50, 2024.
Article in English | MEDLINE | ID: mdl-39155112

ABSTRACT

Siderophore-antibiotic conjugates (SACs) are of past and current interest for delivering antibacterials into Gram-negative bacterial pathogens that express siderophore receptors. Studies of SACs are often multifaceted and involve chemical and biological approaches. Major goals are to evaluate the antimicrobial activity and uptake of novel SACs and use the resulting data to inform further mode-of-action studies and molecular design strategies. In this chapter, we describe four key methods that we apply when investigating the antimicrobial activity and uptake of novel SACs based on the siderophore enterobactin (Ent). These methods are based on approaches from the siderophore literature as well as established protocols for antimicrobial activity testing, and include assays for evaluating SAC antimicrobial activity, time-kill kinetics, siderophore competition, and bacterial cell uptake using 57Fe. These assays have served us well in characterizing our Ent-based conjugates and can be applied to study SACs that use other siderophores as targeting vectors.


Subject(s)
Anti-Bacterial Agents , Enterobactin , Siderophores , Siderophores/chemistry , Siderophores/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Enterobactin/chemistry , Enterobactin/metabolism , Microbial Sensitivity Tests/methods
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