Search Results (28)

Cancer and infectious diseases are major causes of global morbidity and mortality stressing the need to find novel drugs with promising dual anticancer and antimicrobial efficacy. Gold complexes have been studied for the past years due to their anticancer properties, with a few of them displaying antimicrobial properties, which support their pharmacological interest. Within this scope, we investigated six gold bisdithiolate complexes [Au (bdt)₂]⁻ (1), [Au (dcbdt)₂]⁻ (2), [Au (3-cbdt)₂]⁻ (3), [Au (4-cbdt)₂]⁻ (4), [Au (pdt)₂]⁻ (5) and [Au (dcdmp)₂]⁻ (6), and) against the ovarian cancer cell lines A2780 and A2780cisR, the Gram-positive bacteria Staphylococcus aureus Newman, the Gram-negative bacteria Escherichia coli ATCC25922 and Burkholderia contaminans IST408, and the pathogenic yeasts Candida glabrata CBS138 and Candida albicans SC5134. Complexes 2 and 6, with ligands containing aromatic pyrazine or phenyl rings, substituted with two cyanonitrile groups, showed after 24 h of incubation high anticancer activities against A2780 ovarian cancer cells (IC₅₀~5 µM), being also able to overcome cisplatin resistance in A2780cisR cells. Both complexes induced the formation of ROS, activated caspase-3/7, and induced necrosis (LDH release) in a dose-dependent way, in a greater extent in the case of 6. Among the bacterial and fungal strains tested, only complex 6 presented antimicrobial activity against S. aureus Newman, indicating that this complex is a potential novel anticancer and antibacterial agent. These results delve into the structure-activity relationship of the complexes, considering molecular alterations such as replacing a phenyl group for a pyrazine group, and the inclusion of one or two cyanonitrile appendage groups, and their effects on biological activity. Overall, both complexes were found to be promising leads for the development of future anticancer drugs against low sensitive or cisplatin resistant tumors. Full article

Hydroxyapatite (HAp) is a widely used biocompatible material in orthopedic composite preparations. However, HAp composites that exhibit both anticancer and antibacterial activities through bioactive coordination complexes are relatively rare. To explore orthopedic applications, we blended several silver camphorimine compounds with HAp to create [Ag(I)] composites. All compounds [Ag(NO₃)(L)_n] (n = 1,2) based on camphorimine (L^A), camphor sulfonimine (L^B) or imine bi-camphor (L^C) ligands demonstrated significant cytotoxic activity (IC₅₀ = 0.30–2.6 μg_Ag/mL) against osteosarcoma cancer cells (HOS). Based on their structural and electronic characteristics, four complexes (1–4) were selected for antibacterial evaluation against Escherichia coli, Burkholderia contaminans, Pseudomonas aeruginosa, and Staphylococcus aureus. All complexes (1–4) revealed combined anticancer and antibacterial activities; therefore, they were used to prepare [Ag(I)]:HAp composites of 50:50% and 20:80% weight compositions and the activities of the composites were assessed. Results showed that they retain the dual anticancer and antibacterial characteristics of their precursor complexes. To replicate the clinical context of bone-filling applications, hand-pressed surfaces (pellets) were prepared. It is worth highlighting that no agglutination agent was necessary for the pellet’s consistency. The biological properties of the so-prepared pellets were assessed, and the HOS cells and bacteria spreading on the pellet’s surface were analyzed by SEM. Notably, composite 4B, derived from the bicamphor (L^C) complex [Ag(NO₃)(OC₁₀H₁₄N(C₆H₄)₂NC₁₀H₁₄O)], exhibited significant anticancer activity against HOS cells and antibacterial activity against P. aeruginosa, fostering potential clinical applications on post-surgical OS treatment. Full article

The Pseudomonas genus includes ubiquitous bacteria frequently described as animal and human opportunistic pathogens. A 9-year-old cat was referred for rhinoscopy at the Veterinary Hospital of the Faculty of Veterinary Medicine, University of Lisbon, Portugal, for an investigation of the chronic respiratory signs. Upon rhinoscopy, nasal and nasopharyngeal discharge were observed, and the nasal turbinates showed signs of inflammation. The nasal biopsies were evaluated by histopathology and mycological and bacterial cultures. The histopathology revealed chronic lymphoplasmacytic inflammation. The mycological culture was negative, but the bacterial culture revealed the growth of a bacterial isolate in the pure culture, identified as P. aestus by the sequencing of a 1750 bp PCR amplicon obtained with BCR1 and BCR2 primers, followed by homologous sequences analysis using the NCBI database. The isolate’s susceptibility profile towards 14 antimicrobials was evaluated through the disk diffusion method, being observed that it presented a multidrug resistance profile. The studies available on this environmental Pseudomonas strain focused on its potential use for biocide production and application in agricultural settings, and, to the authors’ best knowledge, there are no reports describing its association with infectious diseases in humans or animals, highlighting the importance of establishing protocols aiming at the identification and characterization of non-traditional, multidrug-resistant Pseudomonas in the clinical setting. Full article

The novel hydrosoluble silver coordination polymer [Ag(NO₃)(μ-1κN;2κN′,N″-TPM^OH)]_n (1) (TPM^OH = tris(1H-pyrazol-1-yl)ethanol) was obtained and characterized. While single crystal X-ray diffraction analysis of compound 1 disclosed an infinite 1D helical chain structure in the solid state, NMR analysis in polar solvents confirmed the mononuclear nature of compound 1 in solution. Compound 1 and the analogue [Ag(μ-1κN;2κN′,N″-TPMS)]_n (2) (TPMS = tris(1H-pyrazol-1-yl)methane sulfonate) were evaluated with regard to their antimicrobial activities towards the Gram-negative Escherichia coli, Pseudomonas aeruginosa, and Burkholderia contaminans, the Gram-positive Staphylococcus aureus, and the fungal species Candida albicans and Candida glabrata. Compound 1 exhibited minimal inhibitory concentration (MIC) values ranging from 2 to 7.7 µg/mL towards the tested Gram-negative bacteria, 18 µg/mL towards the Gram-positive S. aureus, and 15 and 31 µg/mL towards C. albicans and C. glabrata, respectively. Compound 2 was less effective towards the tested bacteria, with MIC values ranging from 15 to 19.6 µg/mL towards the Gram-negative bacteria and 51 µg/mL towards S. aureus; however, it was more effective against C. albicans and C. glabrata, with MIC values of about 6 µg/mL towards these fungal species. The toxicity of compounds 1 and 2 was assessed by evaluating the survival of the Caenorhabditis elegans model organism to concentrations of up to 100 µg/mL. The value of 50% lethality (LD₅₀) could only be estimated as 73.2 µg/mL for compound 1 at 72 h, otherwise LD₅₀ was >100 µg/mL for both compounds 1 and 2. These results indicate compounds 1 and 2 as novel silver complexes with interesting antimicrobial properties towards bacterial and fungal pathogens. Full article

Burkholderia cepacia complex infections remain life-threatening to cystic fibrosis patients, and due to the limited eradication efficiency of current treatments, novel antimicrobial therapies are urgently needed. Surface proteins are among the best targets to develop new therapeutic strategies since they are exposed to the host’s immune system. A surface-shaving approach was performed using Burkholderia cenocepacia J2315 to quantitatively compare the relative abundance of surface-exposed proteins (SEPs) expressed by the bacterium when grown under aerobic and microaerophilic conditions. After trypsin incubation of live bacteria and identification of resulting peptides by liquid chromatography coupled with mass spectrometry, a total of 461 proteins with ≥2 unique peptides were identified. Bioinformatics analyses revealed a total of 53 proteins predicted as localized at the outer membrane (OM) or extracellularly (E). Additionally, 37 proteins were predicted as moonlight proteins with OM or E secondary localization. B-cell linear epitope bioinformatics analysis of the proteins predicted to be OM and E-localized revealed 71 SEP moieties with predicted immunogenic epitopes. The protegenicity higher scores of proteins BCAM2761, BCAS0104, BCAL0151, and BCAL0849 point out these proteins as the best antigens for vaccine development. Additionally, 10 of the OM proteins also presented a high probability of playing important roles in adhesion to host cells, making them potential targets for passive immunotherapeutic approaches. The immunoreactivity of three of the OM proteins identified was experimentally demonstrated using serum samples from cystic fibrosis patients, validating our strategy for identifying immunoreactive moieties from surface-exposed proteins of potential interest for future immunotherapies development. Full article

Despite advances in therapies, bacterial chronic respiratory infections persist as life-threatening to patients suffering from cystic fibrosis (CF). Pseudomonas aeruginosa and bacteria of the Burkholderia cepacia complex are among the most difficult of these infections to treat, due to factors like their resistance to multiple antibiotics and ability to form biofilms. The lack of effective antimicrobial strategies prompted our search for alternative immunotherapies that can effectively control and reduce those infections among CF patients. Previous work from our group showed that the anti-BCAL2645 goat polyclonal antibody strongly inhibited Burkholderia cenocepacia to adhere and invade cultured epithelial cells. In this work, we showed that the polyclonal antibody anti-BCAL2645 also strongly inhibited the ability of P. aeruginosa to form biofilms, and to adhere and invade the human bronchial epithelial cell line CFBE41o-. The polyclonal antibody also inhibited, to a lesser extent, the ability of B. multivorans to adhere and invade the human bronchial epithelial cell line CFBE41o. We also show that the ability of B. cenocepacia, P. aeruginosa and B. multivorans to kill larvae of the Galleria mellonella model of infection was impaired when bacteria were incubated with the anti-BCAL2645 antibody prior to the infection. Our findings show that an antibody against BCAL2645 possesses a significant potential for the development of new immunotherapies against these three important bacterial species capable of causing devastating and often lethal infections among CF patients. Full article

The effect of thermal pasteurization (TP, 62.5 °C/30 min—conditions similar to those used in milk banks/hospitals, known as Holder pasteurization) and high-pressure pasteurization (HPP: 400–625 MPa/2.5–30 min) was studied on immunoglobulin (IgG, IgM and IgA) content, lysozyme activity and microbial load of donkey colostrum (in this case, after 40 days at 4 °C). IgG level remained unchanged with HPP at 400 MPa, increased up to 4-fold at 625 MPa/10 min and decreased 90% with TP, while IgM decreased progressively with pressure treatment intensity increment to below the detection limit at 625 MPa and decreased 20% with TP. IgA decreased to below the detection limit after TP and all HPP treatments. Lysozyme activity presented overall a higher decrease after TP (37%) compared to HPP (decreasing from 20% at 400 MPa to about 40% at 600 MPa/10 and 30 min). Furthermore, both total aerobic mesophiles and Enterobacteriaceae remained below detection limits after 40 days of refrigerated storage for both TP and HPP. So, HPP can be considered a potential alternative to the conventional TP to preserve donkey colostrum, with overall equal to better retention, particularly for IgG and lysozyme activity. As far as the authors are aware, this is the first study evaluating the effects of HPP on donkey colostrum, and research in this field should be pursued. Full article

The parasitic protozoan Leishmania (Leishmania) infantum is the etiological agent of human visceral leishmaniasis in South America, an infectious disease associated with malnutrition, anemia, and hepatosplenomegaly. In Brazil alone, around 2700 cases are reported each year. Treatment failure can occur as a result of drug, host, and/or parasite-related factors. Here, we isolated a Leishmania species from a pediatric patient with visceral leishmaniasis that did not respond to chemotherapy, experiencing a total of nine therapeutic relapses and undergoing a splenectomy. The parasite was confirmed as L. (L.) infantum after sequencing of the ribosomal DNA internal transcribed spacer, and the clinical isolate, in both promastigote and amastigote forms, was submitted to in vitro susceptibility assays with all the drugs currently used in the chemotherapy of leishmaniasis. The isolate was susceptible to meglumine antimoniate, amphotericin B, pentamidine, miltefosine, and paromomycin, similarly to another strain of this species that had previously been characterized. These findings indicate that the multiples relapses observed in this pediatric patient were not due to a decrease in the drug susceptibility of this isolate; therefore, immunophysiological aspects of the patient should be further investigated to understand the basis of treatment failure in this case. Full article

The increased demand for alternative sustainable energy sources has boosted research in the field of fuel cells (FC). Among these, microbial fuel cells (MFC), based on microbial anodes and different types of cathodes, have been the subject of renewed interest due to their ability to simultaneously perform wastewater treatment and bioelectricity generation. Several different MFCs have been proposed in this work using different conditions and configurations, namely cathode materials, membranes, external resistances, and microbial composition, among other factors. This work reports the design and optimization of MFC performance and evaluates a hydrogel (Ion Jelly^®) modified air-breathing cathode, with and without an immobilized laccase enzyme. This MFC configuration was also compared with other MFC configuration performances, namely abiotic and biocathodes, concerning wastewater treatment and electricity generation. Similar efficiencies in COD reduction, voltage (375 mV), PD (48 mW/m²), CD (130 mA/m²), and OCP (534 mV) were obtained. The results point out the important role of Ion Jelly^® in improving the MFC air-breathing cathode performance as it has the advantage that its electroconductivity properties can be designed before modifying the cathode electrodes. The biofilm on MFC anodic electrodes presented a lower microbial diversity than the wastewater treatment effluent used as inocula, and inclusively Geobacteracea was also identified due to the high microbial selective niches constituted by MFC systems. Full article

Nanomaterials offer a broad spectrum of applications in biomedicine. The shapes of gold nanoparticles could modulate tumor cell behavior. Spherical (AuNP_sp), stars (AuNP_st) and rods (AuNP_r) shapes of polyethylene glycol coated-gold nanoparticles (AuNPs-PEG) were synthesized. Metabolic activity, cellular proliferation, and reactive oxygen species (ROS) were measured and the impact of AuNPs-PEG in metabolic enzymes function was evaluated by RT-qPCR in PC3, DU145, and LNCaP prostate cancer cells. All AuNPs were internalized, and the different morphologies of AuNPs showed to be an essential modulator of metabolic activity. For PC3 and DU145, the metabolic activity of AuNPs was found to rank in the following order from lowest to highest: AuNP_sp-PEG, AuNP_st-PEG, and AuNP_r-PEG. Regarding LNCaP cells, the AuNP_st-PEG were less toxic, followed by AuNP_sp-PEG and AuNP_r-PEG, but it seems not to be dose-dependent. The proliferation was lower in AuNP_r-PEG in PC3 and DU145 cells but was stimulated around 10% in most conditions (0.001–0.1 mM) in LNCaP cells (not statistically significant). For 1 mM, LNCaP cells showed a significant decrease in proliferation only for AuNP_r-PEG. The outcomes of the current study demonstrated that different AuNPs conformations influence cell behavior, and the correct size and shape must be chosen considering its final application in the field of nanomedicine. Full article

Gold(III) bisdithiolate complexes have been reported as potential antimicrobial and antitumoral agents. The complex [Au(cdc)₂]⁻ (cdc=cyanodithioimido carbonate) displayed antimicrobial and outstanding antitumor activity against the ovarian cancer cells A2780 and A2780cisR, which are sensitive and resistant to cisplatin, respectively. However, poor water solubility may hamper its clinical use. Block copolymer micelles (BCMs) may solubilize hydrophobic drugs, improving their bioavailability and circulation time in blood. Aiming to provide water solubility, prolonged availability, and enhanced therapeutic indexes, BCMs loaded with [Au(cdc)₂]⁻ were synthesized and characterized. The BCM-[Au(cdc)₂] micelles were prepared with a loading efficiency of 64.6% and a loading content of 35.3 mg [Au(cdc)₂]⁻/gBCM. A hydrodynamic diameter of 77.31 ± 27.00 nm and a low polydispersity index of 0.18 indicated that the micelles were homogenous and good candidates for drug delivery. Cytotoxic activity studies against A2780/A2780cisR cells showed that BCM-[Au(cdc)₂] maintained relevant cytotoxic activity comparable to the cytotoxicity observed for the same concentration of gold complexes. The Au uptake in A2780 cells, determined by PIXE, was ca. 17% higher for BCMs-[Au(cdc)₂] compared to [Au(cdc)₂]⁻. The BCMs-[Au(cdc)₂] presented antimicrobial activity against S. aureus Newman and C. glabrata CBS138. These results evidenced the potential of BCM-[Au(cdc)₂] for drug delivery and its promising anticancer and antimicrobial activities. Full article

Current chemotherapy of cutaneous leishmaniasis (CL) is based on repeated systemic or intralesional administration of drugs that often cause severe toxicity. Previously, we demonstrated the therapeutic potential of biodegradable poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) loaded with 8% of the nitrochalcone CH8 (CH8/PLGA) prepared by a conventional bench method. Aiming at an industrially scalable process and increased drug loading, new MPs were prepared by spray drying: CH8/PDE with PLGA matrix and CH8/PVDE with PLGA + polyvinylpyrrolidone (PVP) matrix, both with narrower size distribution and higher drug loading (18%) than CH8/PLGA. Animal studies were conducted to evaluate their clinical feasibility. Both MP types induced transient local swelling and inflammation, peaking at 1–2 days, following a single intralesional injection. Different from CH8/PDE that released 90% of the drug in the ear tissue in 60 days, CH8/PVDE achieved that in 30 days. The therapeutic efficacy of a single intralesional injection was evaluated in BALB/c mice infected with Leishmania (Leishmania) amazonensis and golden hamsters infected with L. (Viannia) braziliensis. CH8/PVDE promoted greater reduction in parasite burden than CH8/PDE or CH8/PLGA, measured at one month and two months after the treatment. Thus, addition of PVP to PLGA MP matrix accelerates drug release in vivo and increases its therapeutic effect against CL. Full article

The discovery of antimicrobials is an outstanding achievement of mankind that led to the development of modern medicine. However, increasing antimicrobial resistance observed worldwide is rendering commercially available antimicrobials ineffective. This problem results from the bacterial ability to adapt to selective pressure, leading to the development or acquisition of multiple types of resistance mechanisms that can severely affect the efficacy of antimicrobials. The misuse, over-prescription, and poor treatment adherence by patients are factors strongly aggravating this issue, with an epidemic of infections untreatable by first-line therapies occurring over decades. Alternatives are required to tackle this problem, and immunotherapies are emerging as pathogen-specific and nonresistance-generating alternatives to antimicrobials. In this work, four types of antibody formats and their potential for the development of antibody-based immunotherapies against bacteria are discussed. These antibody isotypes include conventional mammalian polyclonal antibodies that are used for the neutralization of toxins; conventional mammalian monoclonal antibodies that currently have 100 IgG mAbs approved for therapeutic use; immunoglobulin Y found in birds and an excellent source of high-quality polyclonal antibodies able to be purified noninvasively from egg yolks; and single domain antibodies (also known as nanobodies), a recently discovered antibody format (found in camelids and nurse sharks) that allows for a low-cost synthesis in microbial systems, access to hidden or hard-to-reach epitopes, and exhibits a high modularity for the development of complex structures. Full article

The biological properties of sixteen structurally related monoanionic gold (III) bis(dithiolene/ diselenolene) complexes were evaluated. The complexes differ in the nature of the heteroatom connected to the gold atom (AuS for dithiolene, AuSe for diselenolene), the substituent on the nitrogen atom of the thiazoline ring (Me, Et, Pr, iPr and Bu), the nature of the exocyclic atom or group of atoms (O, S, Se, C(CN)₂) and the counter-ion (Ph₄P⁺ or Et₄N⁺). The anticancer and antimicrobial activities of all the complexes were investigated, while the anti-HIV activity was evaluated only for selected complexes. Most complexes showed relevant anticancer activities against Cisplatin-sensitive and Cisplatin-resistant ovarian cancer cells A2780 and OVCAR8, respectively. After 48 h of incubation, the IC₅₀ values ranged from 0.1–8 $\mathsf{\mu }$M (A2780) and 0.8–29 $\mathsf{\mu }$M (OVCAR8). The complexes with the Ph₄P⁺ ([P]) counter-ion are in general more active than their Et₄N⁺ ([N]) analogues, presenting IC₅₀ values in the same order of magnitude or even lower than Auranofin. Studies in the zebrafish embryo model further showed that, despite their marked anticancer effect, the complexes with [P] counter-ion exhibited low in vivo toxicity. In general, the exocyclic exchange of sulfur by oxygen or ylidenemalononitrile (C(CN)₂) enhanced the compounds toxicity. Most complexes containing the [P] counter ion exhibited exceptional antiplasmodial activity against the Plasmodium berghei parasite liver stages, with submicromolar IC₅₀ values ranging from 400–700 nM. In contrast, antibacterial/fungi activities were highest for most complexes with the [N] counter-ion. Auranofin and two selected complexes [P][AuSBu(=S)] and [P][AuSEt(=S)] did not present anti-HIV activity in TZM-bl cells. Mechanistic studies for selected complexes support the idea that thioredoxin reductase, but not DNA, is a possible target for some of these complexes. The complexes [P] [AuSBu(=S)], [P] [AuSEt(=S)], [P] [AuSEt(=Se)] and [P] [AuSeiPr(=S)] displayed a strong quenching of the fluorescence intensity of human serum albumin (HSA), which indicates a strong interaction with this protein. Overall, the results highlight the promising biological activities of these complexes, warranting their further evaluation as future drug candidates with clinical applicability. Full article

Respiratory infections by bacteria of the Burkholderia cepacia complex (Bcc) remain a life threat to cystic fibrosis (CF) patients, due to the faster lung function decline and the absence of effective eradication strategies. Immunotherapies are regarded as an attractive alternative to control and reduce the damages caused by these infections. In this work, we report the cloning and functional characterization of the OmpA-like BCAL2645 protein, previously identified and found to be immunoreactive against sera from CF patients with a record of Bcc infections. The BCAL2645 protein is shown to play a role in biofilm formation, adherence to mucins and invasion of human lung epithelial cells. The expression of the BCAL2645 protein was found to be increased in culture medium, mimicking the lungs of CF patients and microaerophilic conditions characteristic of the CF lung. Moreover, a polyclonal antibody raised against BCAL2645 was found to inhibit, by about 75 and 85%, the ability of B. cenocepacia K56-2 to bind and invade in vitro CFBE41o- human bronchial epithelial cells. These results highlight the potential of anti-BCAL2645 antibodies for the development of passive immunization therapies to protect CF patients against Bcc infections. Full article