Lactobacillus species are widely recognized for their probiotic potential, focusing on their mechanisms of health benefits and protection. Here we conducted an in vitro investigation of the probiotic potential with a role in microbiome homeostasis of four strains: Lactiplantibacillus plantarum L6 and F53, Ligilactobacillus salivarius 1, and Lactobacillus helveticus 611. A broad spectrum of antibacterial and antifungal activity was determined. The strain-specific inhibition of Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, and saprophytic/toxigenic fungi makes them promising as protective cultures. DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid) measurements showed that tested samples had strain-specific capacity for scavenging of radicals. The molecular base for the antioxidant potential of two lyophilized forms of active strains was investigated by electron paramagnetic resonance spectroscopy. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, with fractions of the most active postbiotics obtained by SEC-FPLC (fast protein liquid chromatography) analysis, showed a wide variety of effects on the growth of a K562 myeloid leukemia cell line. The IC₅₀ (half-maximal inhibitory concentration) of L. salivarius 1 was determined to be 46.15 mg/mL. The proven in vitro functionality of the selected lactobacilli make them suitable for development of target probiotics with specific beneficial effects expected in vivo. Further investigations on produced postbiotics and safety have to be completed before they can be considered as scientifically proven probiotic strains.

Chronic myeloid leukaemia (CML) is the first clonal myeloproliferative disorder of pluripotent stem cells to be associated with a specific genetic abnormality, the Philadelphia chromosome, bearing the BCR-ABL1 fusion oncogene. Tyrosine kinase inhibitors are used as first-line treatment for the chronic phase of CML, although alternative treatments are necessary for resistant cases. Cannabidiol (CBD) is a major constituent of hemp oil that exerts a broad range of pharmacological effects in various malignancies. However, its molecular mechanisms in leukaemia remain unclear.

Chronic myelogenous leukemia (CML) is a clonal myeloproliferative disease driven by the BCR-ABL1 fusion oncogene. Tyrosine kinase inhibitors (TKIs) such as Imatinib mesylate have dramatically improved patient outcomes, yet resistance remains a major obstacle to long-term efficacy. Exosomes, as carriers of bioactive molecules including miRNAs, are increasingly recognized as mediators of drug resistance. CBD has demonstrated antiproliferative and pro-apoptotic effects in several cancer models, but its potential to modulate Imatinib sensitivity or resistance in CML remains unclear. This study aimed to investigate exosomal miRNA signatures associated with Imatinib sensitivity and resistance in the context of treatment with Cannabidiol (CBD), Imatinib mesylate (IM), and their combination. Following treatment with CBD, IM, and CBD+IM, exosomal miRNA profiles in Imatinib-sensitive (K-562S) and Imatinib-resistant (K-562 R) cell lines were analyzed. Gene Ontology (GO) enrichment and semantic clustering was performed. CBD activated tumor-suppressive and apoptosis-related miRNAs in K-562S cells, whereas K-562 R cells showed a dual response involving oncogenic miRNAs and metabolic regulators. IM induced suppressive cascades in K-562S but caused loss of canonical tumor suppressors in K-562 R. CBD+IM produced synergistic amplification of apoptotic and differentiation-related pathways in sensitive cells, while resistant cells showed partial restoration of apoptosis but persistent loss of tumor suppressors. HMGB1-associated miRNAs were identified, of which suppressed were miR-615–5p, miR-4435, let-7 g-3p, and the miR-548 family, alongside upregulated miR-3191–3p and miR-33a-5p. Circulating miRNAs are valuable biomarkers for TKI resistance in CML. Targeting HMGB1-associated miRNAs, together with combined CBD and IM treatment, may help re-establish apoptotic regulation and overcome resistance mechanisms.

Katak, a traditional Bulgarian fermented dairy product distinguished by its unique sensory characteristics and extended shelf life, represents a valuable source of autochthonous microorganisms whose functional and genomic properties remain insufficiently explored. In the present study, strain L3, isolated from katak, was comprehensively characterized by a polyphasic approach integrating classical microbiological methods, molecular identification, and whole-genome sequencing. Functional assessment revealed a broad spectrum of antimicrobial activity against pathogenic bacteria and food-associated fungi, accompanied by pronounced radical-scavenging and antioxidant capacities. The strain also exhibited high transit tolerance in simulated gut passage and a favorable antibiotic susceptibility profile, indicating its potential as a probiotic candidate. Whole-genome sequencing confirmed the taxonomic affiliation of the isolate as Lactiplantibacillus plantarum and enabled the identification of genetic determinants associated with stress response, environmental adaptation, oxidative stress protection, biofilm formation, and antimicrobial activity. The genomic analysis complemented the in vitro findings by identifying genetic determinants consistent with the observed phenotypic traits, supporting the genetic potential of strain L3 for probiotic-associated functions. The integration of phenotypic and genomic evidence allowed a comprehensive evaluation of L. plantarum L3 and demonstrated that its probiotic-related properties are underpinned by a diverse repertoire of functional genes. These findings identify L3 as a promising candidate for further biotechnological/probiotic assessment.