Search Results (20,449)

Glioblastoma remains the most lethal primary malignancy of the central nervous system, and the modest gains achieved with maximal surgery, radiotherapy and temozolomide have not been matched by the immune checkpoint inhibitors and antigen-specific vaccines that reshaped the treatment of many extracranial cancers. The recurrent disappointment of these approaches has been attributed less to a single molecular lesion than to a confluence of obstacles: profound intratumoural heterogeneity, a densely immunosuppressive and myeloid-rich microenvironment, sequestration and exhaustion of conventional T cells, and the practical difficulty of delivering effectors across the blood–brain barrier. Against this background, γδ T cells have attracted interest as an unconventional effector population that recognises transformed cells through stress-associated and metabolic cues rather than peptide–major histocompatibility complex (MHC) complexes, that kills in an MHC-unrestricted manner, and that can be expanded from healthy donors for allogeneic, off-the-shelf use with little expectation of graft-versus-host disease. This narrative review examines, with a deliberately critical lens, the biological rationale and the experimental evidence for γδ T cell-based immunotherapy of glioblastoma. We summarise the developmental biology and functional subsets of human γδ T cells, the natural killer group 2 member D (NKG2D)-, DNAX accessory molecule 1 (DNAM-1)- and T-cell-receptor-dependent mechanisms through which they engage glioblastoma cells and glioma stem-like cells, and the in vitro and animal-model studies that underpin the field, taking care not to overstate efficacy that has so far been demonstrated only in preclinical or early-phase settings. We then weigh the principal opportunities—locoregional and repeated dosing, combination with chemoradiotherapy, checkpoint blockade and antibody-based redirection—against barriers that include limited persistence, uncertain intratumoural trafficking, donor and manufacturing variability, and the unsettled requirements of potency testing and trial design. We give particular weight to what becomes of γδ T cells inside a hostile tumour—the exhaustion-like dysfunction that follows chronic stimulation, the oxygen and glucose dependence of their effector programme, the interleukin-17-polarising signals generated by activated microglia and by genotoxic therapy, and the confounding effect of corticosteroids—together with the engineering and pharmacological strategies proposed to counter them. The first peer-reviewed phase 1 report of intracranially delivered, drug-resistant γδ T cells has now appeared and documents tolerability in a small, single-arm cohort without establishing survival benefit. Throughout, γδ T cells are presented as a biologically plausible but still investigational strategy whose clinical value will be determined by adequately powered trials rather than by mechanistic appeal alone. Full article

Background: Phage therapy is one of the few alternatives to confront the tide of drug-resistant bacteria. Yet phage therapy is often applied knowing little more than that the therapeutic phages can grow on the infecting bacterium. The lack of convenient, inexpensive infection models slows progress in discovering principles that may improve phage therapy success. Here we explore hornworms, the larvae of hawkmoths, as a new model host for phage therapy. Methods: We injected fifth instar hornworms with Pseudomonas aeruginosa and, in some, also simultaneously administered a single dose of one of three phages. Results: Phage treatment significantly improved survival relative to bacteria-only controls, although only modestly. Phages did not significantly affect hornworm weight gain among survivors. Differences in survival and weight among the three phage treatments were not statistically significant despite large genomic differences among the phages. Conclusions: Comparing hornworms to the more commonly used waxworms, hornworms, offers additional phenotypes that can be easily assayed, but their need to be housed individually increases the effort to provide large numbers. Full article

Neglected arboviruses dengue (DENV), Zika (ZIKV), yellow fever (YFV), Japanese encephalitis (JEV), and chikungunya collectively affect hundreds of millions of people annually, yet no specific antiviral drug has been approved for any of them. Alkaloids, nitrogen-containing specialized metabolites produced by diverse plant families, have emerged as a promising source of broad-spectrum antiviral scaffolds. This review compiles and critically analyzes over 100 alkaloid-virus pairs across several RNA virus families, providing a comparative mechanistic analysis. Lycorine, narciclasine, emetine, and berbamine, among others, exhibit potent activity against phylogenetically distant viruses, with the most potent activities reported against flaviviruses (narciclasine: EC₅₀ 0.02 µM against DENV, ZIKV, YFV, and JEV; pancratistatine: 0.0063 µM against ZIKV). Structure-activity analysis of multiple alkaloid classes identifies key pharmacophoric features, including the phenanthridine nucleus (lycorine derivatives) and the bis-benzylisoquinoline scaffold (tetrandrine, berbamine), as determinants of antiviral potency, selectivity, and broad-spectrum activity. Genetic resistance data in West Nile virus challenge the widely accepted model of lycorine as a direct nucleoside inhibitor, instead pointing toward the involvement of the membrane-associated NS4A-2K-NS4B replication complex, though direct validation remains limited for other flaviviruses. Converging structural, biochemical, and transcriptomic evidence suggests that ribosome-mediated translational stress may represent an additional host-directed antiviral mechanism for isoquinoline-type alkaloids, though the causal chain from ribosome binding to activation of the integrated stress response and to antiviral effect has not been established. The present analysis highlights that in vivo validation remains limited to a few alkaloid-virus pairs. Unbiased target deconvolution and formal testing of the ribosome/integrated stress response hypothesis stand out as essential research priorities. Full article

Background: Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD), termed COPD-associated pulmonary hypertension (COPD-PH), and is associated with worse clinical outcomes. The efficacy and safety of pulmonary vasodilators in COPD-PH remain uncertain. Methods: We performed a systematic review and meta-analysis of randomized studies evaluating pulmonary vasodilators in adults with COPD-PH. Fifteen studies were identified, with 11 contributing to quantitative analyses. Outcomes included six-minute walk distance (6MWD), mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), partial pressure of arterial oxygen (PaO₂), and systolic pulmonary arterial pressure (sPAP). Results: Pulmonary vasodilators significantly reduced mPAP (MD −3.88 mmHg, 95% CI −7.23 to −0.53) and PVR (SMD −0.90, 95% CI −1.70 to −0.10). However, no significant improvements were observed in 6MWD or PaO₂. An exploratory composite hemodynamic score supported an overall hemodynamic benefit. Subgroup analyses suggested a more favorable profile for nitric oxide donors, whereas endothelin receptor antagonists were associated with worsened oxygenation. Conclusions: Pulmonary vasodilators improve pulmonary hemodynamics in COPD-PH but do not consistently improve exercise capacity or oxygenation. Current evidence does not support routine use outside specialized centers or clinical trials, and treatment effects appear to vary by drug class. Full article

Background: Serous ovarian cancer (SOC) is the most aggressive subtype of epithelial ovarian cancer, frequently diagnosed at advanced stages with poor prognosis and chemotherapy resistance. Checkpoint kinase 1 (CHEK1), a key regulator of the DNA damage response, is overexpressed in ovarian cancer, making it a promising therapeutic target. No study has systematically evaluated natural compounds as CHEK1 inhibitors in SOC through an integrative transcriptomic and computational framework. Methods: A meta-analysis of three GEO datasets (GSE27651, GSE36668, GSE54388; n = 83) was performed using ImaGEO. DEGs were identified at |log₂FC| ≥ 2 and FDR < 0.05. Pathway enrichment, PPI network analysis, virtual screening of 40 phytochemicals against CHEK1 (PDB: 9CE4), 100 ns MD simulations, and ADMET profiling were conducted using established bioinformatics and computational tools. Results: A total of 511 DEGs were identified, with significant dysregulation of apoptosis, DNA repair, and cell cycle pathways. CHEK1 emerged as the central hub gene. Baicalein exhibited the highest binding affinity (−9.334 kcal/mol), surpassing Prexasertib (−7.2 kcal/mol). MD simulations confirmed complex stability, and ADMET profiling demonstrated favorable drug-likeness with zero Lipinski violations. Conclusions: CHEK1 is established as a validated therapeutic target in SOC, and Baicalein is identified as a computationally superior natural lead compound, warranting experimental validation in ovarian cancer models. Full article

Triple-negative breast cancer (TNBC) remains a highly aggressive malignancy with limited therapeutic options and frequent resistance to platinum-based chemotherapy. Rosmarinic acid (RA), a naturally occurring polyphenol, has attracted considerable interest as a potential chemosensitising agent. This study investigated the anticancer activity and the underlying mechanisms of RA combined with cisplatin (CDDP) in 4T1 breast cancer cells while assessing the cytotoxic responses of non-cancerous HaCaT keratinocytes as a preliminary indicator of differential treatment sensitivity. Cytotoxicity was assessed using the MTT assay, followed by calculation of the Combination Index (CI), Drug Reduction Index (DRI), and Selectivity Index (SI). The generation of intracellular reactive oxygen species (ROS) was evaluated by DCFH-DA fluorescence imaging, and the functional contribution of oxidative stress was examined using N-acetyl-L-cysteine (NAC) rescue experiments. Apoptosis was analysed by Annexin V/PI flow cytometry, NucBlue nuclear staining, and Calcein-AM/propidium iodide (PI) Live/Dead fluorescence imaging. Three-dimensional (3D) tumour spheroids were used to assess treatment-induced alterations in spheroid morphology, morphometric parameters, viability based on adenosine triphosphate (ATP), and Live/Dead staining. The expression of genes related to apoptosis was determined by RT-qPCR, and potential molecular mechanisms were explored using the construction of protein–protein interaction (PPI) networks together with Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses. The combination of RA + CDDP exhibited strong synergistic cytotoxicity in 4T1 cells while demonstrating comparatively lower toxicity toward HaCaT keratinocytes. Combination treatment markedly increased intracellular ROS generation, whereas NAC significantly reduced ROS accumulation and partially restored cell viability, indicating that oxidative stress is a major but not exclusive mediator of cytotoxicity. Combined treatment significantly enhanced apoptotic cell death, increased chromatin condensation and membrane damage, upregulated the expression of Bax, Casp9, Cycs, and Trp53, and downregulated Bcl2, consistent with transcriptional regulation of intrinsic apoptotic signalling. In 3D tumour spheroids, the combination markedly reduced spheroid size, disrupted structural integrity, decreased ATP-based viability, and substantially increased tumour cell death compared to monotherapy. Bioinformatic analyses identified central genes related to apoptosis and cell survival and predicted significant enrichment of PI3K/Akt, p53, MAPK, and apoptosis signalling pathways. RA significantly potentiates the antitumor efficacy of CDDP through synergistic induction of ROS-associated apoptotic signalling while showing a more favourable cytotoxic response in 4T1 breast cancer cells than in non-cancerous HaCaT keratinocytes. The integrated findings from two-dimensional (2D) and 3D models, NAC rescue experiments, molecular analyses, and bioinformatics collectively support the potential of RA as a promising chemosensitising adjuvant for CDDP-based breast cancer therapy and warrant further validation in preclinical in vivo models. Full article

As critical geopolitical and migratory hubs in Eastern Europe, the Azov and Donbas regions represent an epidemiological melting pot for HIV-1 trafficking, exacerbating the global trend of rising dolutegravir (DTG) resistance through the cross-border dissemination of drug-resistant strains. This study presents a comprehensive molecular epidemiological analysis of HIV-1 in these regions in 2025 (N = 1666), focusing on drug resistance and cross-border transmission networks using phylogenetic and molecular network approaches. The study cohort was predominantly female (53.33%) and had heterosexual transmission (78.77%). Most patients (87.64%) received antiretroviral therapy (ART). Sub-subtype A6 predominated, with the radiation’s origin traced to September 1994. Molecular network analysis identified the study area as a significant node, demonstrating viral exports towards the Russian Federation and Belarus, alongside multiple imports from Ukraine, Poland, and Russia. The overall resistance prevalence was 4.49% to integrase strand transfer inhibitors (INSTIs), 2.49% to protease inhibitors (PIs), 12.19% to nucleoside reverse transcriptase inhibitors (NRTIs), and 16.07% to non-nucleoside reverse transcriptase inhibitors (NNRTIs). Surveillance drug resistance mutations in treatment-naive individuals stood at 0.89% (INSTIs), 4.90% (PIs), 4.90% (NRTIs), and 8.82% (NNRTIs). Crucially, intermediate or high-level DTG resistance and key mutations (G118R, R263K, and Y143R) were detected in individuals without prior DTG exposure. This 4.49% integrase inhibitor resistance cannot be considered low; combined with intense cross-border viral dissemination, it may indicate the formation of a stable pool of resistant variants, potentially posing a risk of dolutegravir-based regimen failure and highlighting the need for enhanced regional molecular surveillance. Full article

This review examines the viral quasispecies concept and its implications for understanding viral evolution, pathogenesis, and the development of effective antiviral therapies. Quasispecies are dynamic populations of closely related but genetically distinct viral genomes, which evolve under mutation and Darwinian selection. Notably, minority variants, often dismissed as “genetic noise”, may harbor significant biological differences—such as drug resistance—and become dominant under changing selective pressures. Next-generation sequencing (NGS) has become an indispensable tool for characterizing genetic diversity within quasispecies, enabling detection and quantitative analysis of minority variants often missed by conventional Sanger sequencing, as well as the calculation of diversity indices. We highlight two NGS-based studies of hepatitis B virus quasispecies as illustrative examples of the relevance of minority variants in antiviral resistance and clinical outcomes. These studies also exemplify transcomplementation, whereby defective viral genomes can be replicated and packaged through functional proteins provided by co-infecting variants. Finally, we discuss how the quasispecies concept may extend beyond viruses, with parallels in biological systems such as the adaptive immune system and tumor cell populations. Recognizing quasispecies as dynamic evolving populations rather than static entities is crucial for developing successful strategies to address infectious diseases and other complex biological challenges. Full article

Colorectal cancer (CRC) remains one of the leading causes of cancer-related morbidity and mortality worldwide despite substantial advances in surgery, chemotherapy, targeted therapies, and immunotherapy. The limited efficacy of current treatment strategies in advanced disease and the emergence of therapeutic resistance highlight the urgent need for novel adjunctive therapeutic approaches. Increasing evidence indicates that chronic stress and sustained activation of β-adrenergic signaling promote colorectal tumor initiation, progression, angiogenesis, metastatic dissemination, and immune evasion, thereby identifying this pathway as a potential therapeutic target. Drug repurposing has emerged as an attractive strategy for accelerating the development of new anticancer therapies by identifying novel applications for clinically approved drugs with well-established safety profiles. Among these, β-blockers have gained considerable attention because of their ability to inhibit β-adrenergic signaling and modulate multiple oncogenic pathways implicated in CRC progression. Although accumulating preclinical and observational clinical evidence suggests that β-blockers may possess anticancer potential, the underlying molecular mechanisms and their translational relevance have not yet been comprehensively integrated. This review provides a critical overview of the current evidence regarding the therapeutic potential of β-blockers in CRC by integrating findings from preclinical and clinical studies. Particular emphasis is placed on the regulation of key signaling pathways, including cAMP/PKA/CREB, PI3K/AKT/mTOR, and RAS/RAF/MEK/ERK, as well as on the effects of β-blockers on tumor cell proliferation, apoptosis, angiogenesis, epithelial–mesenchymal transition, metastasis, and modulation of the tumor microenvironment and antitumor immune responses. However, significant barriers limit the translation of these findings into routine clinical practice, including the limited representativeness of preclinical models, potential hemodynamic adverse effects, and the inherent limitations of observational studies. Importantly, owing to the lack of prospective randomized clinical trials, the current evidence remains insufficient to establish the clinical efficacy of β-blockers in colorectal cancer. Although β-blockers possess several characteristics that make them attractive candidates for drug repurposing, including a well-established safety profile, widespread availability, and low cost, further mechanistic studies, prospective randomized clinical trials, and biomarker-based patient stratification are essential to determine their clinical efficacy and define their role in personalized CRC therapy. Full article

Hydrogel-forming microneedles (HFMNs) are minimally invasive interfaces that access interstitial fluid (ISF) through skin penetration, swelling-mediated uptake, analyte diffusion, and hydrated sensor integration. This review examines HFMN architectures, skin–device interfaces, ISF transport, molecular-recognition and signal-transduction strategies, analytical performance, benchmarking, wear-associated failure modes, therapeutic monitoring, and translational priorities. The field has expanded from glucose sensing to metabolites, ions, hormones, proteins, nucleic acids, microbial and wound biomarkers, and therapeutic drugs, enabled by advances in hydrogel chemistry, conductive networks, nanostructured electrodes, catalysis, affinity recognition, molecular imprinting, optical readouts, and multiplexed wearables. Performance remains context dependent and requires physiological range, calibration stability, biofouling resistance, reliable insertion, validated ISF-reference correlations, and interpretable thresholds. Evidence is strongest in artificial matrices, ex vivo tissue, and animals, while human validation remains limited. Translation will require standardized mechanics and transport reporting, longer wear studies, sterilization-compatible chemistries, scalable manufacturing, and clinical validation. HFMNs may complement rather than replace blood-based diagnostics. Full article

Background: Doravirine (DOR) is a new-generation non-nucleoside reverse transcriptase inhibitor, which has emerged as an option for people living with HIV (PLWH) owing to its favorable efficacy and safety profile, unique resistance pathway and limited potential for drug-drug interactions. Methods: This retrospective chart review study aimed to better understand DOR-based treatment use in Greece, PLWH characteristics, and drivers of treatment switch. Eligible individuals were adult PLWH who were switched to a DOR-based regimen based on the physician’s decision. Individuals exposed to DOR at any time prior to switching to the DOR-based regimen were excluded. Results: From 12 July 2023 to 31 October 2023, 110 PLWH were consecutively enrolled across 6 public hospital clinics. At baseline (closest prior to or on the date of first DOR prescription), the mean age of PLWH was 49.3 years, 90.9% were males, 88.2% were asymptomatic, 86.5% were virologically suppressed, 33.6% were suffering from multimorbidity (excluding infections/infestations), 45.5% were receiving comedications for their comorbidities, and 5.5% were co-infected with Hepatitis C virus. Most PLWH (98.2%) were prescribed DOR plus two nucleoside reverse transcriptase inhibitors; 87.3% were prescribed DOR/Lamivudine/Tenofovir Disoproxil Fumarate fixed-dose combination. PLWH started DOR a median of 11.7 years after first-ever antiretroviral therapy initiation, corresponding to 2nd/3rd/≥4th antiretroviral line in 33.6%/33.6%/32.7% of participants, respectively; 60.9% of them were proactively switched to a DOR-based regimen. The most common reasons for switching were ‘regimen simplification’ (42.7%), ‘tolerability’ (26.4%) and ‘prevention of toxicities’ (18.2%). Conclusions: This study highlights the patterns of DOR use in real-life clinical practice in Greece among treatment-experienced PLWH. Physicians switch HIV-1-infected individuals from prior ART to DOR-based regimens to offer a simplified regimen or to avoid or prevent toxicity. Full article

Bovine mastitis, caused by both contagious and environmental pathogens, represents a major infectious disease burden in the global dairy industry. Antibiotics remain the primary treatment option, but their effectiveness is limited by the blood–milk barrier, drug residues, and the growing threat of multidrug-resistant bacteria. Among the various alternatives, phage therapy has drawn particular attention due to its specificity, ability to disrupt biofilms, low impact on commensal flora, and self-replication at infection sites. In this review, we summarize recent advances in the isolation of lytic phages targeting major mastitis-causing pathogens, their bactericidal mechanisms, and their performance in vitro and in vivo. We also discuss key obstacles to clinical translation including formulation stability, narrow host range, and safety concerns. Moreover, the potential strategies to overcome these issues are explored. This review provides a useful reference for research on phage therapy against bovine mastitis. Full article

Background/Objectives: Advanced prostate cancer remains difficult to treat because docetaxel, although clinically important, is limited by systemic toxicity, poor tumor selectivity, and acquired resistance. Camptothecin is a potent anticancer agent, but its clinical application is restricted by poor solubility and instability. This study investigated the synergy between docetaxel and camptothecin and developed transferrin-conjugated, camptothecin-bearing dendrimersomes entrapping docetaxel as a targeted nanocarrier for prostate cancer therapy. Methods: Drug synergy was evaluated in PC3-Luc cells using an MTT assay and combination index analysis. Transferrin-conjugated, disulfide-linked camptothecin-bearing PEGylated DAB dendrimers were synthesized and characterized by ¹H-NMR, critical aggregation concentration analysis, transmission electron microscopy, and entrapment efficiency measurements. pH- and redox-dependent drug release was assessed by dialysis. Cellular uptake and uptake mechanisms were investigated by confocal microscopy, flow cytometry, and inhibitor studies in PC3-Luc, DU145, and LNCaP cells. Anti-proliferative efficacy was determined by an MTT assay. Results: Docetaxel and camptothecin showed marked synergy in PC3-Luc cells, with a minimum combination index of 0.20 ± 0.01 and 88.10 ± 0.41% growth inhibition at low nanomolar concentrations. Transferrin-conjugated dendrimersomes self-assembled into spherical vesicles with a critical aggregation concentration of approximately 250 µg/mL. They had high docetaxel entrapment efficiency (89.10 ± 0.08%) and enhanced drug release under acidic and reductive conditions. They significantly increased cellular uptake of docetaxel relative to non-targeted dendrimersomes (by up to 3-fold) and free drugs (by up to 20-fold), mainly through transferrin receptor-mediated endocytosis, and improved anti-proliferative activity in all three cell lines. Tf-conjugated DPSSC produced the lowest IC₅₀ values among the tested formulations: 11.72 ± 1.02 nM in PC3-Luc, 9.88 ± 1.22 nM in DU145, and 7.88 ± 1.35 nM in LNCaP cells. Conclusions: Transferrin-conjugated camptothecin-based dendrimersomes entrapping docetaxel represent a promising multifunctional nanocarrier for prostate cancer that combines synergistic dual-drug therapy, active targeting, and stimulus-responsive release, supporting further evaluation as a selective delivery strategy in advanced prostate cancer using preclinical models and in vivo studies. Full article

Background/Objectives: Antimicrobial stewardship programmes (ASPs) are essential for improving antimicrobial use and limiting the emergence of antimicrobial resistance. Although national ASP key performance indicators (KPIs) have been implemented across Saudi Ministry of Health (MOH) hospitals, large-scale evaluations of programme performance remain limited. This study evaluated national ASP performance across MOH hospitals from 2021 to 2024 using formal KPIs and complementary stewardship measures. Methods: This retrospective multicentre surveillance analysis included 124,452 antimicrobial prescription reviews from 96 Saudi MOH hospitals actively reporting stewardship activities. Hospitals were classified according to ASP capacity as category A, B, or C. The evaluated KPIs included protocol adherence, restricted-antibiotic dispensing compliance, active intervention rate, annual trends in optimization interventions, and physician acceptance of ASP recommendations. Secondary assessments included appropriateness of therapy management, therapeutic drug monitoring (TDM) for vancomycin and aminoglycosides, and hospital-level antimicrobial use expressed as defined daily doses per 100 available bed-days. Multivariable logistic regression was used to identify factors associated with guideline non-adherence and physician non-acceptance. Results: Overall protocol adherence was 87.1%, exceeding the national target of 80%, while the active intervention rate was 64.6%, exceeding the 60% benchmark. Restricted-antibiotic dispensing compliance reached 87.6% but remained below the 100% target. Physician acceptance of ASP recommendations was high at 93.0%, although it did not achieve the national target of 98%. The optimization-intervention KPI was not met because de-escalation, antibiotic discontinuation, and intravenous-to-oral conversion did not demonstrate a sustained annual increase. Appropriate ongoing therapy management was documented in 68.3% of cases with available data, whereas TDM was requested in 44.5% of eligible vancomycin or aminoglycoside cases. Antimicrobial use varied across years and hospital categories, with higher monitored broad-spectrum and reserve-agent use in higher-capacity hospitals. Lower ASP capacity, non-critical care settings, and combination therapy were consistently associated with less favourable stewardship outcomes. Conclusions: Saudi MOH hospitals actively reporting stewardship activities demonstrated favourable performance in protocol adherence, intervention activity, and physician acceptance. However, persistent gaps in restricted-antibiotic dispensing, optimization interventions, TDM, and inter-hospital variation indicate the need for continued strengthening of ASP infrastructure, monitoring, and feedback systems. Future research should link stewardship indicators with clinical outcomes, antimicrobial resistance trends, and patient safety. Full article

Lactic acid bacteria (LAB) are promising oral drug delivery systems due to their probiotic properties, safety, and ability to stimulate mucosal immunity. In this study, we characterized five LAB strains, Lacticaseibacillus casei ATCC 393, Lacticaseibacillus paracasei UST1611, Lactiplantibacillus plantarum UST1611, Limosilactobacillus reuteri LR08, and Lacticaseibacillus rhamnosus GG, to assess their potential as a microbial chassis for oral drug delivery. We tested competence for transformation, plasmid stability, GFP expression under a constitutive promoter, survival under simulated gastrointestinal conditions, and survival in the gut of Danio rerio larvae. Successful transformation with the pTRKH3-ermGFP plasmid was achieved in L. casei ATCC 393, L. paracasei UST1611, and L. reuteri LR08. We also showed that the L. casei ATCC 393 strain had significantly higher protein expression than its L. paracasei UST1611 and L. reuteri LR08 counterparts. In the absence of selection, L. casei ATCC 393 and L. paracasei UST1611 retained their plasmid for 48 h. L. reuteri LR08 retained it for up to 72 h. The three transformed strains showed comparable tolerance to simulated gastrointestinal pH, though L. casei and L. reuteri were more resistant to 0.3% greater bile. In vivo testing showed the highest survival for L. casei ATCC 393 and L. paracasei UST1611 in the gut of zebrafish (Danio rerio) larvae. Overall, our results suggest that, among the five strains tested, L. casei ATCC 393 is the most promising candidate for an LAB-based microbial system for oral drug delivery. Full article