Search Results (460)

This review explores the biofilm architecture and drug resistance of Enterococcus faecalis in clinical and environmental settings. The biofilm in E. faecalis is a heterogeneous, three-dimensional, mushroom-like or multilayered structure, characteristically forming diplococci or short chains interspersed with water channels for nutrient exchange and waste removal. Exopolysaccharides, proteins, lipids, and extracellular DNA create a protective matrix. Persister cells within the biofilm contribute to antibiotic resistance and survival. The heterogeneous architecture of the E. faecalis biofilm contains both dense clusters and loosely packed regions that vary in thickness, ranging from 10 to 100 µm, depending on the environmental conditions. The pathogenicity of the E. faecalis biofilm is mediated through complex interactions between genes and virulence factors such as DNA release, cytolysin, pili, secreted antigen A, and microbial surface components that recognize adhesive matrix molecules, often involving a key protein called enterococcal surface protein (Esp). Clinically, it is implicated in a range of nosocomial infections, including urinary tract infections, endocarditis, and surgical wound infections. The biofilm serves as a nidus for bacterial dissemination and as a reservoir for antimicrobial resistance. The effectiveness of first-line antibiotics (ampicillin, vancomycin, and aminoglycosides) is diminished due to reduced penetration, altered metabolism, increased tolerance, and intrinsic and acquired resistance. Alternative strategies for biofilm disruption, such as combination therapy (ampicillin with aminoglycosides), as well as newer approaches, including antimicrobial peptides, quorum-sensing inhibitors, and biofilm-disrupting agents (DNase or dispersin B), are also being explored to improve treatment outcomes. Environmentally, E. faecalis biofilms contribute to contamination in water systems, food production facilities, and healthcare environments. They persist in harsh conditions, facilitating the spread of multidrug-resistant strains and increasing the risk of transmission to humans and animals. Therefore, understanding the biofilm architecture and drug resistance is essential for developing effective strategies to mitigate their clinical and environmental impact. Full article

Drug resistance in Candida may result in either a fitness cost or a fitness advantage. Candida auris, whose intrinsic drug resistance remains unclear, has emerged as a significant human pathogen. We aimed to investigate whether Candida fitness, including early interaction with the host innate immune system, depends on the antifungal susceptibility phenotype and putative-associated resistance mutations. We compared interleukin-1β, interleukin-6, interleukin-8, and tumor necrosis factor α production by human colorectal adenocarcinoma cells stimulated by fluconazole-susceptible and fluconazole-resistant strains of Candida albicans, C. parapsilosis, C. tropicalis, and C. glabrata, as well as fluconazole-resistant C. auris strains. Sensitive Candida strains induced lower cytokine levels compared with C. auris and resistant strains, except for TNF a. Resistant strains induced cytokine levels like C. auris, except for higher IL-1β and lower TNF-α. Susceptible strains exhibited cytokine profiles distinct from those of resistant strains. C. auris induced cytokine levels comparable to resistant strains but displayed profiles resembling those of susceptible strains. This study highlights the relationship among antifungal susceptibility, fungal fitness and host early immunity. C. auris behavior appears to be between fluconazole-sensitive and fluconazole-resistant strains. Understanding these dynamics may enhance the knowledge of the survival and reproduction of resistant Candida and the epidemiology of fungal infections. Full article

Docetaxel is a chemotherapeutic agent widely used for breast cancer treatment; however, its efficacy is often limited by drug resistance and associated toxicity. This review examines the molecular mechanisms of docetaxel resistance in breast cancer and discusses research advances and future directions for overcoming this challenge. Key resistance mechanisms include alterations in drug targets (microtubules), increased drug efflux, suppression of apoptosis, activation of survival signalling pathways, epithelial-to-mesenchymal transition (EMT), and cancer stem cell enrichment. An evolutionary perspective distinguishes between intrinsic and acquired resistance, emphasising the need for adaptive therapeutic strategies. Recent advances in genomic profiling, non-coding RNA research, novel drug combinations, and biomarker-guided therapies have also been reviewed. Emerging approaches, such as targeting the tumour microenvironment, harnessing immunotherapy, and implementing adaptive dosing schedules, have been discussed. This review emphasises the understanding of resistance as a multifactorial phenomenon that requires multipronged interventions. Research has aimed to identify predictive biomarkers, develop targeted agents to reverse resistance, and design rational combination strategies to improve patient outcomes. Progress in deciphering and targeting docetaxel resistance mechanisms holds promise for enhancing treatment responses and extending survival in patients with breast cancer. Full article

Background: The global spread of antibiotic-resistant bacteria presents a major public health challenge and necessitates the development of innovative antimicrobial agents. Artificial intelligence (AI)-driven drug discovery has recently enabled the repurposing of existing compounds with novel therapeutic potential. Halicin, originally developed as an anti-diabetic molecule, has been identified through AI screening as a promising antibiotic candidate due to its broad-spectrum activity, including efficacy against multidrug-resistant pathogens. Methods: In this study, the antibacterial activity of halicin was evaluated against a range of clinically relevant multidrug-resistant bacterial strains. Bacterial isolates were first characterized using the agar disk diffusion method with a panel of 22 conventional antibiotics to confirm resistance profiles. The minimum inhibitory concentration (MIC) of halicin was then determined for selected isolates, including Escherichia coli ATCC^® 25922™ and Staphylococcus aureus ATCC^® 29213™, using broth microdilution according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: Halicin demonstrated notable antibacterial activity, with MIC values of 16 μg/mL and 32 μg/mL against E. coli ATCC^® 25922™ and S. aureus ATCC^® 29213™, respectively. A dose-dependent inhibition of bacterial growth was observed for the majority of tested isolates, except for Pseudomonas aeruginosa, which exhibited intrinsic resistance. This lack of susceptibility is likely related to reduced outer membrane permeability, limiting the intracellular accumulation of halicin. Conclusions: Our findings support the potential of halicin as a novel antimicrobial agent for the treatment of infections caused by antibiotic-resistant bacteria. However, further investigations, including pharmacokinetic, pharmacodynamic, and toxicity studies, are essential to assess its clinical safety and therapeutic applicability. Full article

Encouraging discoveries and excellent advances in the fight against cancer have led to innovative therapies such as photothermal therapy (PTT), photodynamic therapy (PDT), drug targeting (DT), gene therapy (GT), immunotherapy (IT), and therapies that combine these treatments with conventional chemotherapy (CT). Furthermore, 2,041,910 new cancer cases and 618,120 cancer deaths have been estimated in the United States for the year 2025. The low survival rate (<50%) and poor prognosis of several cancers, despite aggressive treatments, are due to therapy-induced secondary tumorigenesis and the emergence of drug resistance. Moreover, serious adverse effects and/or great pain usually arise during treatments and/or in survivors, thus lowering the overall effectiveness of these cures. Although prevention is of paramount importance, novel anticancer approaches are urgently needed to address these issues. In the field of anticancer nanomedicine, carbon nanotubes (CNTs) could be of exceptional help due to their intrinsic, unprecedented features, easy functionalization, and large surface area, allowing excellent drug loading. CNTs can serve as drug carriers and as ingredients to engineer multifunctional platforms associated with diverse treatments for both anticancer therapy and diagnosis. The present review debates the most relevant advancements about the adjuvant role that CNTs could have in cancer diagnosis and therapy if associated with PTT, PDT, DT, GT, CT, and IT. Numerous sensing strategies utilising various CNT-based sensors for cancer diagnosis have been discussed in detail, never forgetting the still not fully clarified toxicological aspects that may derive from their extensive use. The unsolved challenges that still hamper the possible translation of CNT-based material in clinics, including regulatory hurdles, have been discussed to push scientists to focus on the development of advanced synthetic and purification work-up procedures, thus achieving more perfect CNTs for their safer real-life clinical use. Full article

Breast cancer remains a leading cause of mortality among women worldwide. Surgery, radiation therapy, chemotherapy, and hormone-based treatments are standard therapeutic approaches, but drug resistance and adverse effects necessitate the search for novel anticancer agents. Quinazolinedione derivatives have emerged as potential anticancer compounds due to their cytotoxic and apoptosis-inducing properties. This study aimed to evaluate the apoptotic induction of previously reported quinazolinedione derivatives on MCF-7 breast cancer cells. The cytotoxic effect was assessed using the MTT assay, apoptosis was quantified by Annexin V-PE/7AAD staining and flow cytometry, and apoptosis-related protein expression was analyzed via multiplexed bead-based immunoassays. These findings indicate that two derivatives in the series significantly reduced the cell viability in a dose-dependent manner. Apoptosis was induced primarily through the intrinsic apoptotic pathway as evidenced by the upregulation of caspase-9 and p53 and the downregulation of Bcl-2 and p-Akt. These results highlight quinazolinedione derivatives as promising candidates for breast cancer therapy prompting further investigation into their molecular mechanisms and potential clinical applications. Full article

After the era of multidrug resistance (MDR) against cytotoxic chemotherapy, the development of resistance against newly developed molecularly targeted drugs also seems inevitable. While the mechanisms involved in resistance against these two categories of anticancer drugs are different, the principles are similar: inherent resistance (also known as primary resistance) is a result of heterogeneity in cancer cells where a subpopulation of the cells do not show a favorable initial response to the drug, while acquired resistance (or secondary resistance), as the name suggests, is developed after repeated treatments due to the plasticity of cancer cells. Despite the introduction of a variety of molecularly targeted drugs to clinical practice, chemotherapy is still at the forefront of the battle against cancer. In this manuscript, we review the major mechanisms involved in MDR and resistance against different categories of molecularly targeted drugs separately, and review some of the strategies studied to overcome the resistance against cancer therapy. While MDR mechanisms have been reviewed previously, the molecular mechanisms of resistance to the latest generations of anticancer drugs are rarely reviewed as a group, and the connection between the two categories of resistance is often missing in this type of publication. Our aim is to illustrate a comprehensive picture of what the landscape of cancer treatment is today with respect to resistance. While this picture seems bleak, and it is the common belief that resistance is inevitable, understanding the mechanisms involved could potentially lead to more efficient approaches to overcoming this so far unbeatable obstacle. Full article

Platinum resistance represents an urgent medical need in the management of ovarian cancer. The activity of the combinations of onvansertib, an inhibitor of polo-like kinase 1, with gemcitabine or carboplatin was tested using patient-derived xenografts of high-grade serous ovarian carcinoma resistant to cisplatin (DDP). Two PDX models were selected from our xenobank: one with acquired resistance to DDP (#266R) and the other (#315) with intrinsic DDP resistance. Tumor-bearing mice were randomized to receive vehicle, single onvansertib, gemcitabine and carboplatin, and their combinations. Onvansertib/gemcitabine and onvansertib/carboplatin combinations were well tolerated. In the #266R model, single drug treatments were completely inactive, while the combinations of onvansertib/gemcitabine and onvansertib/carboplatin resulted in a significant increase in survival compared to controls and single drugs (p < 0.001 versus control, onvansertib, gemcitabine and carboplatin). Similar efficacy was observed in the s.c. #315 PDX model; indeed, onvansertib and carboplatin monotherapies were inactive, gemcitabine monotherapy was marginally active, while both combinations were highly active. The molecular mechanism underlying the efficacy of the combinations suggests a higher induction of DNA damage which seems plausible considering that, in both cases, gemcitabine and carboplatin, respectively, interfere with DNA metabolism and induce alkylation damage. The results suggest that the combinations of onvansertib/gemcitabine and onvansertib/carboplatin are safe and were shown to be of therapeutic value in the platinum-resistant setting of ovarian carcinoma, strongly supporting their clinical translatability. Full article

Mycobacterium abscessus complex (MABc) poses a major therapeutic challenge due to its intrinsic multidrug resistance and ability to form biofilms. This study evaluated the in vitro activity of three antimycobacterial agents—bedaquiline, delamanid, and clofazimine—on 20 clinical MABc isolates, including M. abscessus subsp. abscessus, massiliense, and bolletii, with a focus on biofilm-forming phenotypes. Biofilm analysis showed that the rough colony morphotypes were mostly weak biofilm formers, while the smooth and mixed morphotypes were predominantly moderate or strong biofilm formers. A statistically significant association was observed between the mixed colony morphology and strong biofilm formation (p = 0.032). Importantly, bedaquiline exhibited potent and consistent activity across all isolates, regardless of the biofilm-forming ability, with MIC values ranging from 0.125 to 1 µg/mL. In contrast, delamanid and clofazimine showed limited efficacy, with MIC values exceeding 16 µg/mL and 8 µg/mL, respectively. These findings strongly support the role of bedaquiline as a promising core agent for future combination therapies targeting drug-resistant MABc infections, including biofilm-associated infections. Our results, among the first from Poland, highlight the critical need for incorporating novel agents such as bedaquiline into therapeutic strategies against this difficult-to-treat pathogen. Full article

Immunotherapy has significantly changed the treatment paradigm for solid tumors, with immune checkpoint inhibitors now established in the management of many malignancies. Despite initial success, durable responses remain limited to a subset of patients, often less than 30%, due to both intrinsic and acquired resistance mechanisms. These challenges have prompted the development of next-generation immunotherapies. Recent efforts have expanded the scope of immunotherapy beyond PD-1/PD-L1 and CTLA-4 inhibition, focusing on new immune targets currently under investigation in early phase clinical trials. These include novel immune checkpoint inhibitors, immunomodulators targeting the tumor microenvironment, and bispecific antibodies. This review provides a comprehensive overview of emerging immune targets currently being investigated in early drug development, discussing their mechanisms of action, preliminary clinical outcomes, and potential future directions. Full article

Background/Objectives: Medulloblastoma is a rare tumor that represents almost two-thirds of all embryonal pediatric brain tumor cases. Current treatments, including surgery, radiation, and chemotherapy, are often associated with adverse effects, such as toxicity, resistance, and lack of specificity. According to multiple bulk and single-cell omics-based approaches, it is now clear that each molecular subgroup of medulloblastoma possesses intrinsic genetic and molecular features that could drive the definition of distinct therapeutic targets, and of markers that have the potential to improve diagnosis. Nanomedicine offers a promising approach to overcome these challenges through precision-targeted therapies and theranostic platforms that merge diagnosis and treatment. This review explores the role of nanomedicine in medulloblastoma. Here, possible theranostic nanoplatforms combining targeted drug delivery and simultaneous imaging are reviewed, highlighting their potential as tools for personalized medicine. Methods: We performed a chronological analysis of the literature by using the major web-based research platforms, focusing on molecular targets, and the potential application of nanomedicine to overcome conventional treatment limitations. Results: Advances in nanoparticle-based drug delivery systems enable selective targeting of key molecular pathways, improving therapeutic efficacy while minimizing off-target effects. Additionally, nanotechnology-based imaging agents, including MRI contrast agents and fluorescent probes, improve diagnostic accuracy and treatment monitoring. Despite these advantages, some significant challenges remain, including overcoming the blood–brain barrier, ensuring biocompatibility, and addressing regulatory pathways for clinical translation. Conclusions: In conclusion, we sought to identify the current knowledge on the topic and hope to inspire future research to obtain new nanoplatforms for personalized medicine. Full article

Background: Several targeted drugs have been recently approved for the treatment of PIK3CA-mutated hormone receptor-positive (HR+)/HER2-negative (HER2−) breast cancer (BC). This study aimed at a comprehensive evaluation of the spectrum of PIK3CA alterations in Russian BC patients. Methods: The tumor material from 1872 patients with ER+/HER2− BC was tested by a combination of PCR-based methods. Results: Mutations were detected in 693/1872 (37%) cases, including 46 BC with two PIK3CA lesions. The three most common substitutions (E542K, E545K, and H1047R) were identified in 542/693 (78%) PIK3CA-mutated cases, while as many as 5.5–12% of identified mutations were not potentially detectable by common commercial kits. The study included patients of Slavic and non-Slavic ethnicities residing in regions with different climate conditions, however, these factors did not influence the distribution of PIK3CA mutations. The presence of PIK3CA variants was associated with older patient age at diagnosis (p = 0.0002), smaller tumor size (p = 0.005), lower grade (p = 0.005), Ki67 <20% (p = 0.0001) and progesterone receptor-positive status (p = 0.002) at the initial disease diagnosis, and fewer distant metastases at the time of the detection of BC spread (p = 0.0001). In a subgroup of 413 BC patients who received adjuvant tamoxifen or aromatase inhibitors, PIK3CA mutations were not associated with resistance to either type of treatment. Conclusions: The results of this study highlight the need to extend the PIK3CA testing beyond the hotspot regions of this gene. Although PIK3CA alterations contribute to the pathogenesis of HR+/HER2− BC and represent a target for several novel drugs, they are not intrinsically associated with unfavorable clinical characteristics of this subtype of cancer disease. Full article

The alarming increase in antimicrobial resistance has intensified the search for novel therapeutic agents capable of combating resistant microbial strains. Copper complexes have emerged as promising antimicrobial agents due to their intrinsic redox activity, ability to disrupt microbial membranes, and interactions with vital biomolecules such as DNA and proteins. This review critically evaluates the antimicrobial potential of copper complexes reported between 2018 and 2025, emphasizing their structural diversity, mechanisms of action, and biological performance against a wide range of bacterial and fungal pathogens. Key findings reveal that Schiff base copper complexes, amino acid derivatives, heterocyclic ligands, and mixed-ligand systems exhibit potent antimicrobial activities, often surpassing standard antibiotics. Mechanistically, copper complexes induce reactive oxygen species (ROS) generation, inhibit enzyme function, cause DNA cleavage, and compromise cell membrane integrity. Furthermore, structure–activity relationship (SAR) analyses indicate that ligand type, coordination geometry, and lipophilicity significantly influence antimicrobial efficacy. Overall, the reviewed studies support the development of copper-based compounds as viable candidates for antimicrobial drug development. This review also identifies current challenges and gaps in knowledge, such as limited in vivo studies and toxicity assessments, which must be addressed to advance these compounds toward clinical application. Full article

Background: Malaria significantly impacts the health of populations living in poverty and vulnerable conditions. Resistance to current antimalarial drugs remains a major challenge and highlights the urgent need for novel, effective, and safer therapies. Violacein, a purple pigment, has demonstrated potent antiplasmodial activity, making it a promising antimalarial candidate. However, to date, no in vitro metabolism studies of violacein have been published. In this study, the metabolic stability of violacein was evaluated using human (HLMs), mouse (MLMs), and rat (RLMs) liver microsomes and the metabolites generated by HLMs and RLMs were assessed. Methods: Liquid chromatography quadrupole mass spectrometry (LC-MS/MS) was used to investigate the metabolic stability of violacein, while liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was used to identify the metabolites. In silico analyses were used to support in vitro metabolite identification by providing insights into potential metabolic pathways and predicting metabolite structures, thereby enhancing the accuracy and efficiency of the identification process. Results: The half-life (t_1/2) for violacein in RLMs, MLMs, and HLMs was 36, 81, and 216 min, respectively. The in vitro intrinsic clearance (CL_{int, in vitro}) values were 38.4, 17.0, and 6.4 µL/min/mg for RLMs, MLMs, and HLMs, respectively, while the in vivo intrinsic clearance (CL_{int, in vivo}) was 93.7, 67.0, and 6.6 mL/min/kg, respectively. A slow elimination profile was observed in HLMs followed by MLMs, with rapid elimination in RLMs, indicating greater stability of violacein in HLMs and MLMs when compared with RLMs. Four violacein metabolites were identified in HLMs and RLMs, two of which were formed by phase I metabolism, one by phase II metabolism, and one by phase I + II metabolism. Conclusions: This study provides the first published analysis of the metabolic stability of violacein. Full article

Background/Objectives: Ovarian cancer remains one of the most commonly diagnosed malignancies among women worldwide. The heterogeneity among tumor subtypes and the emergence of treatment resistance have raised significant concerns regarding the long-term efficacy of chemotherapy, radiotherapy, and immunotherapy. In response to these challenges, drug repurposing strategies—utilizing existing drugs in novel therapeutic contexts—have gained increasing attention. This study aimed to investigate the cytotoxic and apoptotic effects of the combined application of doxorubicin (DX) and thymoquinone (TQ) on ovarian adenocarcinoma cells (OVCAR3). Methods: OVCAR3 cells were cultured in RPMI medium supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin. Cell viability and proliferation were assessed using the MTT assay following treatment with various concentrations of DX and TQ. NucBlue immunofluorescence staining was employed to examine nuclear morphology and to identify apoptosis-associated changes. Additionally, quantitative real-time polymerase chain reaction (qRT-PCR) was per-formed to evaluate the expression levels of apoptosis-related and oncogenic pathway genes, including RAF, RAS, Bcl-2, and Bax. Results: The results demonstrated that the combination of DX and TQ significantly reduced OVCAR3 cell viability and induced apoptosis in a dose-dependent manner. qRT-PCR analysis revealed a downregulation of RAS, RAF, and Bcl-2 expression, along with an upregulation of Bax, indicating activation of the intrinsic apoptotic pathway. These findings suggest that thymoquinone exerts an-ti-proliferative and pro-apoptotic effects by modulating the RAS/RAF signaling cascade. Furthermore, the co-administration of thymoquinone with doxorubicin potentiated these effects, suggesting a synergistic interaction between the two agents. Conclusions: Histopathological and molecular evaluations further confirmed the activation of apoptosis and the suppression of key oncogenic pathways. Collectively, these results underscore the therapeutic potential of thymoquinone as both a monotherapy and an adjuvant to conventional chemotherapy, warranting further validation in preclinical and clinical studies. Full article