Susceptibility of Leishmania to novel pentavalent organometallics: Investigating impact on DNA and membrane integrity in antimony(III)-sensitive and -resistant strains

The aim the present study was to investigate the impact of novel pentavalent organobismuth and organoantimony complexes on membrane integrity and their interaction with DNA, activity against Sb(III)-sensitive and -resistant Leishmania strains and toxicity in mammalian peritoneal macrophages. Ph3M(L)2 type complexes were synthesized, where M = Sb(V) or Bi(V) and L = deprotonated 3-(dimethylamino)benzoic acid or 2-acetylbenzoic acid. Both organobismuth(V) and organoantimony(V) complexes exhibited efficacy at micromolar concentrations against Leishmania amazonensis and L. infantum but only the later ones demonstrated biocompatibility. Ph3Sb(L1)2 and Ph3Bi(L1)2 demonstrated distinct susceptibility profiles compared to inorganic Sb(III)-resistant strains of MRPA-overexpressing L. amazonensis and AQP1-mutated L. guyanensis. These complexes were able to permeate the cell membrane and interact with the Leishmania DNA, suggesting that this effect may contribute to the parasite growth inhibition via apoptosis. Taken altogether, our data substantiate the notion of a distinct mechanism of uptake pathway and action in Leishmania for these organometallic complexes, distinguishing them from the conventional inorganic antimonial drugs.

Organogold(III)-dithiocarbamate compounds and their coordination analogues as anti-tumor and anti-leishmanial metallodrugs

The limited chemical stability of gold(III)-based compounds in physiological environment has been a challenge in drug discovery, and organometallic chemistry might provide the solution to overcome this issue. In this work, four novel cationic organogold(III)-dithiocarbamate complexes of general structure [(C^N)AuIIIDTC]PF6 (C1a - C4a, DTC = dithiocarbamate, L1 - L4, C^N = 2-anilinopyridine) are presented, and compared to their coordination gold(III)-dithiocarbamate analogues [AuIIIDTCCl2] (C1b - C4b), as potential anti-cancer and anti-leishmanial drugs. Most of the complexes effectively inhibited cancer cell growth, notably C3a presented anti-proliferative effect in the nanomolar range against breast cancer (MCF-7 and MDA-MB-231 cells with moderate selectivity. Pro-apoptotic studies on treated MCF-7 cells showed a high population of cells in early apoptosis. Reactivity studies of C3a towards model thiols (N-acetyl-L-cysteine) refer to a possible mode of action involving bonding between the organogold(III)-core and the thiolate. In the scope of neglected diseases, gold complexes are emerging as promising therapeutic alternatives against leishmaniasis. In this regard, all gold(III)-dithiocarbamate complexes presented anti-leishmanial activity against at least one Leishmania species. Complexes C1a, C4a, C1b, C4b were active against all tested parasites with IC50 values varying between 0.12 and 42 μM, and, overall, organometallic compounds presented more intriguing inhibition profiles. For C4a selectivity over 500-fold for L. braziliensis; even higher than the reference anti-leishmanial drug amphotericin B. Overall, our findings revealed that the organogold(III) moiety significantly amplified the anti-cancer and anti-leishmanial effects with respect to the coordination analogues; thus, showing the great potential of organometallic chemistry in metallodrug-based chemotherapy for cancer and leishmaniasis.

In vitro and in vivo acute toxicity of an artificial butter flavoring

Flavorings used in cookies, electronic cigarettes, popcorn, and breads contain approximately 30 chemical compounds, which makes it difficult to determine and correlate signs and symptoms of acute, subacute or chronic toxicity. The aim of this study was to characterize a butter flavoring chemically and subsequently examine the in vitro and in vivo toxicological profile using cellular techniques, invertebrates, and lab mammals. For the first time, the ethyl butanoate was found as the main compound of a butter flavoring (97.75%) and 24 h-toxicity assay employing Artemia salina larvae revealed a linear effect and LC₅₀ value of 14.7 (13.7-15.7) mg/ml (R² = 0.9448). Previous reports about higher oral doses of ethyl butanoate were not found. Observational screening with doses between 150-1000 mg/kg by gavage displayed increased amount of defecation, palpebral ptosis, and grip strength reduction, predominantly at higher doses. The flavoring also produced clinical signs of toxicity and diazepam-like behavioral changes in mice, including loss of motor coordination, muscle relaxation, increase of locomotor activity and intestinal motility, and induction of diarrhea, with deaths occurring after 48 h exposure. This substance fits into category 3 of the Globally Harmonized System. Data demonstrated that butter flavoring altered the emotional state in Swiss mice and disrupted intestinal motility, which may be a result of neurochemical changes or direct lesions in the central/peripheral nervous systems.

Nanoparticles Obtained from Zein for Encapsulation of Mesalazine

We encapsulated MSZ in zein nanoparticles (NP-ZN) using a desolvation method followed by drying in a mini spray dryer. These nanoparticles exhibited a size of 266.6 ± 52 nm, IPD of 0.14 ± 1.1 and zeta potential of -36.4 ± 1.5 mV, suggesting colloidal stability. Quantification using HPLC showed a drug-loaded of 43.8 µg/mg. SEM demonstrated a spherical morphology with a size variation from 220 to 400 nm. A FTIR analysis did not show drug spectra in the NPs in relation to the physical mixture, which suggests drug encapsulation without changing its chemical structure. A TGA analysis showed thermal stability up to 300 °C. In vitro release studies demonstrated gastroresistance and a sustained drug release at pH 7.4 (97.67 ± 0.32%) in 120 h. The kinetic model used for the release of MSZ from the NP-ZN in a pH 1.2 medium was the Fickian diffusion, in a pH 6.8 medium it was the Peppas-Sahlin model with the polymeric relaxation mechanism and in a pH 7.4 medium it was the Korsmeyer-Peppas model with the Fickian release mechanism, or "Case I". An in vitro cytotoxicity study in the CT26.WT cell line showed no basal cytotoxicity up to 500 μg/mL. The NP-ZN showed to be a promising vector for the sustained release of MSZ in the colon by oral route.

Catalyst-Free Click Chemistry for Engineering Chondroitin Sulfate-Multiarmed PEG Hydrogels for Skin Tissue Engineering

The quest for an ideal biomaterial perfectly matching the microenvironment of the surrounding tissues and cells is an endless challenge within biomedical research, in addition to integrating this with a facile and sustainable technology for its preparation. Engineering hydrogels through click chemistry would promote the sustainable invention of tailor-made hydrogels. Herein, we disclose a versatile and facile catalyst-free click chemistry for the generation of an innovative hydrogel by combining chondroitin sulfate (CS) and polyethylene glycol (PEG). Various multi-armed PEG-Norbornene (A-PEG-N) with different molecular sizes were investigated to generate crosslinked copolymers with tunable rheological and mechanical properties. The crosslinked and mechanically stable porous hydrogels could be generated by simply mixing the two clickable Tetrazine-CS (TCS) and A-PEG-N components, generating a self-standing hydrogel within minutes. The leading candidate (TCS-8A-PEG-N (40 kD)), based on the mechanical and biocompatibility results, was further employed as a scaffold to improve wound closure and blood flow in vivo. The hydrogel demonstrated not only enhanced blood perfusion and an increased number of blood vessels, but also desirable fibrous matrix orientation and normal collagen deposition. Taken together, these results demonstrate the potential of the hydrogel to improve wound repair and hold promise for in situ skin tissue engineering applications.

Short interfering RNA delivered by a hybrid nanoparticle targeting VEGF: Biodistribution and anti-tumor effect

BACKGROUND

The use of RNA interference (iRNA) therapy has proved to be an interesting target therapy for the cancer treatment; however, siRNAs are unstable and quickly eliminated from the bloodstream. To face these barriers, the use of biocompatible and efficient nanocarriers emerges as an alternative to improve the success application of iRNA to the cancer, including breast cancer.

RESULTS

A hybrid nanocarrier composed of calcium phosphate as the inorganic phase and a block copolymer containing polyanions as organic phase, named HNPs, was developed to deliver VEGF siRNA into metastatic breast cancer in mice. The particles presented a rounded shape by TEM images with average size measured by DLS suitable and biocompatible for biomedical applications. The XPS and EDS spectra confirmed the hybrid composition of the nanoparticles. Moreover, after intravenous administration, the particles accumulated mainly in the tumor site and kidneys, which demonstrates the tumor targeting accumulation through the Enhanced Permeability and Retention Effect (EPR). A significant decrease in size of the tumors treated with the nanoparticles containing siVEGF (HNPs-siVEGF) was observed and the reduction was related to enhanced tumor accumulation of siRNA as well as in vivo VEGF silencing at gene and protein levels.

CONCLUSION

The hybrid system prepared was successful in promoting the RNAi effect in vivo with very low toxicity.

GENERAL SIGNIFICANCE

This study shows the valuable development of a hybrid nanoparticle carrying VEGF siRNA, as well as their tumor targeting, accumulation and reduction in mice triple-negative breast cancer.

Antiproliferative and Genotoxic Action of an Underexploited Organoteluran Derivative on Sarcoma 180 Cells

BACKGROUND

The search for novel metallic chemical compounds with toxicogenic effects has been of great importance for more efficient cancer treatment.

OBJECTIVE

The study evaluated the cytotoxic, genotoxic and mutagenic activity of organoteluran RF07 in the S-180 cell line.

METHODS

The bioassays used were cell viability with 3-(4,5-dimethyl-2-thiazole)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, evaluation of apoptosis and necrosis using fluorescence and flow cytometry, cytokinesisblock micronucleus test and comet assay. The compound was tested at 1; 2.5 and 5μM.

RESULTS

The results showed the cytotoxicity of RF07 at concentrations of 2.5, 5, 10 and 20μM when compared to the negative control. For genotoxicity tests, RF07 showed effects in all concentrations assessed by increased index and frequencies of damage and mutagenic alterations. The compound was also cytotoxic due to the significant decrease in the nuclear division index, with significant values of apoptosis and necrosis. The results of fluorescence and flow cytometry showed apoptosis as the main type of cell death caused by RF07 at 5μM, which is thought to avoid an aggressive immune response of the organism.

CONCLUSION

In addition to cytotoxic and genotoxic effects, RF07 creates good perspectives for future antitumor formulations.

α-Phellandrene exhibits antinociceptive and tumor-reducing effects in a mouse model of oncologic pain

Medical reports indicate a prevalence of pain in 50% of patients with cancer. In this context, this article investigated the antinociceptive activity of α-PHE using in vivo Sarcoma-180-induced hypernociception in mice to detail its mechanism(s) of antinociception under different conditions of treatment and tumor progression. Firsty, in vitro cytotoxic action was assessed using melanoma B-16/F-10 and S-180 murine cells and colorimetric MTT assays. For in vivo studies, acute treatment with α-PHE (6.25, 12.5, 25 and 50 mg/kg orally by gavage) was performed on the 1st day after S-180 inoculation. Subacute treatments were performed for 8 days starting on the next day (early protocol) or on day 8 after S-180 inoculation (late protocol). For all procedures, mechanical nociceptive evaluations were carried out by von Frey's technique in the subaxillary region peritumoral tissue (direct nociception) and in right legs of S-180-bearing mice (indirect nociception). α-PHE showed in vitro cytotoxic action on B-16/F-10 and S-180 (CI₅₀ values of 436.0 and 217.9 μg/mL), inhibition of in vivo tumor growth (ranging from 47.3 to 82.7%) and decreased direct (peritumoral tissue in subaxillary region) and indirect (right leg) mechanical nociception in Sarcoma 180-bearing mice with early and advanced tumors under acute or subacute conditions of treatment especially at doses of 25 and 50 mg/kg. It improved serum levels of GSH as well as diminished systemic lipid peroxidation, blood cytokines (interleukin-1β, -4, -6, and tumor necrosis factor-α). Such outcomes highlight α-PHE as a promising lead compound that combines antinociceptive and antineoplasic properties. Its structural simplicity make it a cost-effective alternative, justifying further mechanistic investigations and the development of pharmaceutical formulations. Moreover, the protocols developed and standardized here make it possible to use Sarcoma-180 hypernociception model to evaluate the capacity of new antinociceptive molecules under conditions of cancer-related allodynia.

Proteins from Rhinella jimi parotoid gland secretion: A comprehensive analytical approach

Toad skin secretions are sources of complex mixtures of bioactive compounds, such as proteins and peptides. Rhinella jimi species is a common toad in the Brazilian northeast, considered by only a few known studies. The experimental design was applied to optimize the protein extraction method from R. jimi parotoid gland secretions. The optimum condition was using 100 mmol L^-1 Tris-HCl buffer pH 7.2 under vortexing for 5 min. The FTIR analysis combined with PCA revealed high-protein purity of the extracts, confirming the success of the proposed extraction method. The total protein concentration by the Bradford method was 102.4 and 66.5 mg g^-1 on toad poisons from Teresina and Picos, respectively. The comparative proteomic analysis using HPLC-SEC-DAD and 1D SDS-PAGE revealed significant differences in protein abundance. HMW biomolecules showed greater abundance in toads from Teresina, while LMW protein species were more abundant in toads from Picos. The significant difference in amphibian proteome can be attributed to the edaphoclimatic conditions of their habitat. The cytotoxicity of the protein extract from Teresina was higher on the tumor cell lines 4T1 and CT26.WT. These new findings are fundamental for future studies the on identity and biological activity of biomolecules from this noble sample.

Non-clinical toxicity of (+)-limonene epoxide and its physio-pharmacological properties on neurological disorders

The compound (+)-limonene epoxide has antioxidant, anxiolytic, and antihelminthic properties. However, investigations to determine its long-term exposure were not performed. We investigated the systemic toxicological profile after chronic exposure as well as the antidepressant and antiepileptic potentialities of (+)-limonene epoxide on mice. Initially, we evaluated acute toxicity on Artemia salina nauplii and cytotoxicity on mice erythrocytes and peripheral blood mononuclear cells (PBMC). Aftterwards, mice were chronically treated for 120 days by gavage with (+)-limonene epoxide (25, 50, and 75 mg/kg/day) and this exposure was assessed by pathophysiological measurements. For antidepressant and anticonvulsivant analysis, we performed the forced swimming and tail suspension protocols and pentylenetetrazol- and picrotoxin-induced seizures, respectively. (+)-Limonene epoxide showed a LC50 value of 318.7 μg/mL on A. salina shrimps, caused lysis of red blood cells at higher concentrations only but did not show cytotoxicity on PMBC, which suggests pharmacological safety if plasma concentrations do not exceed 100 μg/mL. Macroscopic, hematological, clinical chemistry, and nutritional changes were not detected, though focal areas of hepatic necrosis, inflammatory infiltrate, and karyolysis have been detected at 75 mg/kg/day. The compound inhibited the developing of pentylenetetrazol- and picrotoxin-induced seizures, decreased deaths, and reduced immobility times, mainly at 75 mg/kg. So, it reversed reserpine effects, suggesting antidepressant effects should be linked to serotonergic and/or adrenergic transmission. It is feasible that (+)-limonene epoxide plays a benzodiazepine-like anticonvulsive action and may be also recommended as an antidote for poisonings caused by central depressants.

Synthesis of silver-cerium titanate nanotubes and their surface properties and antibacterial applications

Nano-heterostructures of titanate nanotubes were synthesized and they revealed a complex structure with the formation of TiO₂ (anatase), CeO₂, Ag₂O and metallic silver nanoparticles on the outer walls and intercalation of Ce⁴⁺ and Ag⁺ into the interlayer spaces of the nanotubes by microwave-assisted hydrothermal process and subjected to ion exchange reactions. To the best of our knowledge, this is the first reported silver and cerium co-exchanged titanate nanotubes for bio-applications. The co-ion exchange processes preserved the original tubular structure of titanate nanotubes with significant changes of the superficial as well as interlamellar environment. This study opens up possibility of synthesizing complex, functional nano-heterostructure with the scope of modification of the final structure, especially the amount and oxidation state of the intercalated cation (Ce⁴⁺, Ce³⁺ and Ag⁺) as well as the quantity and variety of the decorating nanoparticles (CeO₂, Ag₂O or metallic Ag). The interplay of which, in turn, can lead to important biological properties and applications, owing to their ion-liberation capacity. The samples were tested in antibacterial activity with two different kind of bacteria (gram positive and negative), cell cytotoxicity and adhesion, and it was found that the nano-heterostructure formed shows high antibacterial activity with low cytotoxicity and high cell adhesion, which makes it a promising material for further health applications.

Modified pyrazole platinum(II) complex can circumvent albumin and glutathione: Synthesis, structure and cytotoxic activity

The synthesis and structural characterization of novel platinum complexes ([Pt^II(Pz)₂Cl₂] - C1, C2 and C3) featuring diphenyl-pyrazole derived ligands: para-fluorophenyl and para-substituted phenyl (CH₃, F and Cl for L1, L2 and L3, respectively) were reported and it was also evaluated their potential antitumor activity. The elemental, molar conductivity and thermogravimetric analysis combined with FTIR, UV-vis, NMR and mass spectrometry are in agreement with the chemical structure indicated by single-crystal X-ray diffraction. The antiproliferative activities were assessed against tumor (B16F10 and 4T1) and non-tumor (BHK21) cell lines, and the cytotoxicity of the compounds was strongly increased after metal complexation displaying promising activity. It was also assessed the ability of extracellular bovine serum albumin (BSA) and glutathione (GSH) to decrease the cytotoxicity of the complexes against B16F10. It was highlighted that only the C3 activity was not disturbed in those conditions, being confirmed by flow cytometry using Anexin-V/PI to evaluate interferences in the apoptosis process, even it was not predicted by molecular docking simulations. The interaction of the synthesized compounds with calf-thymus DNA (ctDNA) and bovine serum albumin (BSA) was also investigated through spectrophotometric assays and molecular docking simulations, indicating that C1 and C2 presented better interaction with the biomacromolecules than the corresponding ligands. In addition, agarose gel electrophoresis with plasmid DNA revealed that C1-C3 are capable of interaction with DNA and modify its electrophoretic mobility.

Synthesis and anticancer evaluation of new lipophilic 1,2,4 and 1,3,4-oxadiazoles

A series of1,2,4- and 1,3,4-oxadiazole derivatives were synthesized and evaluated for their anticancer activity. Halogenated 1,2,4-oxadiazoles were obtained from benzonitrile and coupled either lipophilic amines or with aminoalcohols. Lipophilic 1,3,4-oxadiazole derivatives were obtained through the Mannich reactions between 5-(aryl)-1,3,4-oxadiazole-2-thiol and alkylated or acylated amines. The in vitro cytotoxic effects were evaluated against 4T1- mammary carcinoma and CT26 - colon cancer cells. The best results were obtained for the 1,3,4-oxadiazole coupled to alkylated piperazine with 10-14 carbon chain moiety, with IC₅₀ values ranging from 1.6 to 3.55μΜ for the 4T1 cell line, and from 1.6 to 3.9 μM for the CT26.WT cell line, and selectivity index up to 19. The most potent compounds were investigated with AnnexinV and PI staining as indicative of apoptosis induction.

The Pollutant Organotins Leads to Respiratory Disease by Inflammation: A Mini-Review

Organotins (OTs) are organometallic pollutants. The OTs are organometallic pollutants that are used in many industrial, agricultural, and domestic products, and it works as powerful biocidal compound against large types of microorganisms such as fungi and bacteria. In addition, OTs are well known to be endocrine-disrupting chemicals, leading abnormalities an "imposex" phenomenon in the female mollusks. There are some studies showing that OTs' exposure is responsible for neural, endocrine, and reproductive dysfunctions in vitro and in vivo models. However, OTs' effects over the mammalian immune system are poorly understood, particularly in respiratory diseases. The immune system, as well as their cellular components, performs a pivotal role in the control of the several physiologic functions, and in the maintenance and recovery of homeostasis. Thus, it is becoming important to better understand the association between environmental contaminants, as OTs, and the physiological function of immune system. There are no many scientific works studying the relationship between OTs and respiratory disease, especially about immune system activation. Herein, we reported studies in animal, humans, and in vitro models. We searched studies in PUBMED, LILACS, and Scielo platforms. Studies have reported that OTs exposure was able to suppress T helper 1 (Th1) and exacerbate T helper 2 (Th2) response in the immune system. In addition, OTs' contact could elevate in the airway inflammatory response, throughout a mechanism associated with the apoptosis of T-regulatory cells and increased oxidative stress response. In addition, OTs induce macrophage recruitment to the tissue, leading to the increased necrosis, which stimulates an inflammatory cytokines secretion exacerbating the local inflammation and tissue function loss. Thus, the main intention of this mini-review is to up to date the main findings involving the inflammatory profile (especially Th1 and Th2 response) in the respiratory tract as a result of OTs' exposure.

Antiangiogenesis, loss of cell adhesion and apoptosis are involved in the antitumoral activity of Proteases from V. cundinamarcensis (C. candamarcensis) in murine melanoma B16F1

The proteolytic enzymes from V. cundinamarcensis latex, (P1G10), display healing activity in animal models following various types of lesions. P1G10 or the purified isoforms act as mitogens on fibroblast and epithelial cells by stimulating angiogenesis and wound healing in gastric and cutaneous ulcers models. Based on evidence that plant proteinases act as antitumorals, we verified this effect on a murine melanoma model. The antitumoral effect analyzed mice survival and tumor development after subcutaneous administration of P1G10 into C57BL/6J mice bearing B16F1 low metastatic melanoma. Possible factors involved in the antitumoral action were assessed, i.e., cytotoxicity, cell adhesion and apoptosis in vitro, haemoglobin (Hb), vascular endothelial growth factor (VEGF), tumor growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α) content and N-acetyl-glucosaminidase (NAG) activity. We observed that P1G10 inhibited angiogenesis measured by the decline of Hb and VEGF within the tumor, and TGF-β displayed a non-significant increase and TNF-α showed a minor non-significant reduction. On the other hand, there was an increase in NAG activity. In treated B16F1 cells, apoptosis was induced along with decreased cell binding to extracellular matrix components (ECM) and anchorage, without impairing viability.