Search

In this study, phosphate-buffered saline solution (PBS) was successfully radiolabeled with technetium-99m. The biodistribution profile and bone accumulation of the [99mTc]Tc-PBS system were evaluated in healthy swiss mice. The radiolabeling of the system was successfully obtained, yielding around 90 % of radiochemical purity. The system stability was tested in the presence of saline medium at 25 oC and mouse plasma at 37 oC, and results revealed that [99mTc]Tc-PBS showed excellent stability over time, in both media. It was observed a biphasic clearance profile, with fast elimination from the bloodstream by renal filtration. The radiolabeled system revealed a high specificity bone accumulation was observed, demonstrating an uptake behavior from 20 to 50 times higher than muscle, used as control. From all results obtained, the system constituted by [99mTc]Tc-PBS can be considered a potential selective agent for bone imaging.

Irinotecan (IRN) is a semisynthetic derivative of camptothecin that acts as a topoisomerase I inhibitor. IRN is used worldwide for the treatment of several types of cancer, including colorectal cancer, however its use can lead to serious adverse effects, as diarrhea and myelosuppression. Liposomes are widely used as drug delivery systems that can improve chemotherapeutic activity and decrease side effects. Liposomes can also be pH-sensitive to release its content preferentially in acidic environments, like tumors, and be surface-functionalized for targeting purposes. Herein, we developed a folate-coated pH-sensitive liposome as a drug delivery system for IRN to reach improved tumor therapy without potential adverse events. Liposomes were prepared containing IRN and characterized for particle size, polydispersity index, zeta potential, concentration, encapsulation, cellular uptake, and release profile. Antitumor activity was investigated in a murine model of colorectal cancer, and its toxicity was evaluated by hematological/biochemical tests and histological analysis of main organs. The results showed vesicles smaller than 200 nm with little dispersion, a surface charge close to neutral, and high encapsulation rate of over 90%. The system demonstrated prolonged and sustained release in pH-dependent manner with high intracellular drug delivery capacity. Importantly, the folate-coated pH-sensitive formulation had significantly better antitumor activity than the pH-dependent system only or the free drug. Tumor tissue of IRN-containing groups presented large areas of necrosis. Furthermore, no evidence of systemic toxicity was found for the groups investigated. Thus, our developed nanodrug IRN delivery system can potentially be an alternative to conventional colorectal cancer treatment.

International audience; Side effects often limit the use of doxorubicin (DOX) in cancer treatment. We have recently developed a nanostructured lipid carrier (NLC) formulation for synergistic chemotherapy, encapsulating DOX and the anticancer adjuvants docosahexaenoic acid (DHA) and α-tocopherol succinate (TS). Hydrophobic ion-pairing with TS allowed a high DOX entrapment in the nanocarrier. In this work, we investigated the pharmacokinetics of this formulation after intravenous administration in mice. The first data obtained led us to propose synthesizing covalent DOX-TS conjugates to increase DOX retention in the NLC. We successfully conjugated DOX to TS via an amide or hydrazone bond. In vitro studies in 4T1 tumor cells indicated low cytotoxicity of the amide derivative, while the hydrazone conjugate was effective in killing cancer cells. We encapsulated the hydrazone derivative in a DHA-based nanocarrier (DOX-hyd-TS/NLC), which had reduced particle size and high drug encapsulation efficiency. The pH-sensitive hydrazone bond allowed controlled DOX release from the NLC, with increased drug release at acidic conditions. In vivo studies revealed that DOX-hyd-TS/NLC had a better pharmacokinetic profile than free DOX and attenuated the short-term cardiotoxic effects caused by DOX, such as QT prolongation and impaired left ventricular systolic function. Moreover, this formulation showed excellent therapeutic performance by reducing tumor growth in 4T1 tumor-bearing mice and decreasing DOX-induced toxicity to the heart and liver, demonstrated by hematologic, biochemical, and histologic analyses. These results indicate that DOX-hyd-TS/NLC may be a promising nanocarrier for breast cancer treatment.

In the last few decades, utilization of medicinal plants by the pharmaceutical industry has led to the identification of many new bioactive compounds. The genus Pterodon, native of the Brazilian Flora, is known for the therapeutic properties attributed to its species, which are widely used in popular medicine for their anti-inflammatory, anti-rheumatic, tonic, and depurative properties. The intrinsic low water solubility of the plant derivatives from the genus, including diterpenes with vouacapane skeletons that are partially associated with the pharmacological activities, impairs the bioavailability of these bioactive compounds. Recent studies have aimed to encapsulate Pterodon products to improve their water solubility, achieve stability, increase their efficacy, and allow clinical applications. The purpose of this paper is to review recent research on the use of nanotechnology for the development of new products from plant derivatives of the Pterodon genus in different types of micro- and nanocarriers. Therapeutic properties of their different products are also presented. Finally, an update about the current and future applications of encapsulated formulations is provided.

Made available in DSpace on 2022-04-28T19:45:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study aims to demonstrate the applicability and importance of zebrafish (Danio rerio) model to study acute and chronic inflammatory responses induced by different stimuli: carrageenan phlogogen (nonimmune); acute infection by bacteria (immune); foreign body reaction (chronic inflammation by round glass coverslip implantation); reaction induced by xenotransplantation. In addition to the advantages of presenting low breeding cost, high prolificity, transparent embryos, high number of individuals belonging to the same spawning and high genetic similarity that favor translational responses to vertebrate organisms like humans, zebrafish proved to be an excellent tool, allowing the evaluation of edema formation, accumulation of inflammatory cells in the exudate, mediators, signaling pathways, gene expression and production of specific proteins. Our studies demonstrated the versatility of fish models to investigate the inflammatory response and its pathophysiology, essential for the successful development of studies to discover innovative pharmacological strategies. Laboratory of Animal Pharmacology and Toxicology Brazil University (UB) Department of Preventive Veterinary Medicine São Paulo State University (UNESP) Department of Morphology Federal University of Minas Gerais (UFMG) Department of Physiology and Pharmacology Federal University of Minas Gerais (UFMG) Department of Biochemistry and Immunology Federal University of Minas Gerais (UFMG) Department of zootechnics at the Veterinary School Federal University of Minas Gerais (UFMG) Postgraduate Program in Health Sciences - PROCISA Federal University of Roraima Immunochemistry Laboratory Butantan Institute Department of Clinical and Toxicological Analyses Federal University of Minas Gerais (UFMG) Department of Pharmacology University of São Paulo (ICB-USP) Department of Preventive Veterinary Medicine São Paulo State University (UNESP) FAPESP: 2013/25971-9 FAPESP: 2018/07098-0 FAPESP: 2019/19939-1 CNPq: 301473 / 2016-1 CNPq: 307526/2018-6 CNPq: 477816/2013-4

Combination therapy between paclitaxel (PTX) and doxorubicin (DXR) is applied as the first-line treatment of breast cancer. Co-administration of drugs at synergistic ratio for treatment is facilitated with the use of nanocarriers, such as liposomes. However, despite the high response rate of solid tumors to this combination, a synergism of cardiotoxicity may limit the use. Thus, the objective of this work was to investigate the toxicity of long-circulating and fusogenic liposomes co-encapsulating PTX and DXR at the synergistic molar ratio (1:10) (LCFL-PTX/DXR). For this, clinical chemistry, histopathological analysis and electrocardiographic exams were performed on female Balb/c mice that received a single intravenous dose of LCFL-PTX/DXR. The results of the study indicated that the LD50 dose range (lethal dose for 50% of animals) of the LCFL-PTX/DXR treatment (28.9-34.7 mg/kg) is much higher than that found for free PTX/DXR treatment (20.8-23.1 mg/kg). In addition, liposomes promoted cardiac protection by not raising CK-MB levels in animals, keeping cardiomyocytes without injury or electrocardiographic changes. After 14 days of treatment, free PTX/DXR caused prolongation of the QRS interval when compared to LCFL-PTX/DXR treatment at the same dose (37.0 ± 5.01 ms and 30.83 ± 2.62 ms, respectively, with p = 0.017). The survival rate of animals treated with LCFL-PTX/DXR was three times higher than that of those treated with free drugs. Thus, it was established that the toxicity of LCFL-PTX/DXR is reduced compared to the combination of free PTX/DXR and this platform has advantages for the clinical treatment of breast cancer.

The development of nanomaterials that are capable of recognizing disease-specific biomarkers with high sensitivity and specificity is related to several advances in the field of nanomedicine. Furthermore, the targeted delivery of anticancer agents to tumor tissues enhances their efficiency and reduces their toxic side effects. Boron nitride nanotubes (BNNTs) are nanostructured materials, analog to carbon nanotubes, which present good biocompatibility and morphology suitable for tumor cell internalization. CREKA is a pentapeptide that has a high affinity to fibrin, a protein found in the new tumor vessels in the early stages of metastasis and in thrombosis regions. In this study BNNTs were chemically functionalized with the peptide CREKA, and this system was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential, scanning electron microscopy, and transmission electron microscopy. After the mentioned chemical steps, the FTIR analysis shows an organic phase related to the CREKA, TGA indicates that about 10% of the peptide is firmly attached to BNNT surface. In addition, the radiolabeling process was successful, achieving the purity required for the biodistribution study. In vivo experiments showed that a considerable amount of BNNT-CREKA was accumulated at the tumor and metastasis sites. The present results indicate an effective targeting of the system to tumor and metastasis sites. Further studies can reveal potential applications of functionalized BNNTs in cancer treatment.

Background: The co-encapsulation of paclitaxel (PTX) and doxorubicin (DXR) in liposomes has the potential to offer pharmacokinetic and pharmacodynamic advantages, providing delivery of both drugs to the tumor at the ratio required for synergism. Objective: To prepare and characterize long-circulating and fusogenic liposomes co-encapsulating PTX and DXR in the 1:10 molar ratio (LCFL-PTX/DXR). Methods: LCFL-PTX/DXR was prepared by the lipid film formation method. The release of PTX and DXR from liposomes was performed using a dialysis method. Studies of cytotoxicity, synergism, and cellular uptake were also carried out. Results: The encapsulation percentage of PTX and DXR was 74.1 ± 1.8 % and 89.6 ± 12.3%, respectively, and the mean diameter of the liposomes was 244.4 ± 28.1 nm. The vesicles remained stable for 30 days after their preparation. The drugs were simultaneously released from vesicles during 36 hours, maintaining the drugs combination in the previously established ratio. Cytotoxicity studies using 4T1 breast cancer cells showed lower inhibitory concentration 50% (IC50) value for LCFL-PTX/DXR treatment (0.27 ± 0.11 µm) compared to the values of free drugs treatment. In addition, the combination index (CI) assessed for treatment with LCFL-PTX/DXR was equal to 0.11 ± 0.04, showing strong synergism between the drugs. Cell uptake studies have confirmed that the molar ratio between PTX and DXR is maintained when the drugs are administered in liposomes. Conclusion: It was possible to obtain LCFL-PTX/DXR suitable for intravenous administration, capable of releasing the drugs in a fixed synergistic molar ratio in the tumor region.

Silver tungstate nanoparticles have been presenting attractive characteristics that could allow its usage in the biomedical sciences. In this study, Ag2WO4 nanoparticles with an average size of 242 nm were obtained and radiolabeled with technetium-99m with high labeling-yield as well as high stability. Biodistribution studies were carried out in healthy and tumor-bearing mice to determine the nanoparticle’s in vivo behavior. The results revealed an important tumor-to-muscle ratio, reaching values above than 1.5, demonstrated the ability of this nanomaterial in accumulating preferentially in tumor tissue. All results together, converge to consider the Ag2WO4 nanoparticles as a potential system against cancer and a potential new radiolabeled probe for tumor identification and uptake.

Aim Breast cancer is a health problem worldwide with high incidence and mortality rates. It is well known that the development of more sensitive and specific diagnostic methods is of great importance since an early diagnosis is essential to successfully treat tumors. Lapachol is a natural compound, belonging to the naphthoquinone group that has been widely used in traditional medicine to treat various illnesses, including cancer. The aim of this study was to evaluate technetium-99m-labeled lapachol as an imaging probe for breast cancer identification. Methods To achieve this purpose, lapachol was labeled with technetium-99m, radiochemical purity and in vitro stability were determined. Blood clearance, in healthy mice, and biodistribution, in 4T1 tumor-bearing mice, were also evaluated. Results Lapachol was successfully labeled with technetium-99m, with high values of radiochemical yield (95.9 ± 3.4%). In vitro stability showed that the radiolabeled complex remained stable for up to 24 h, with values above 90% for both saline and plasma (95.6 ± 3.6% and 96.4 ± 1.7%, respectively). The radiolabeled complex decays in a biphasic manner, with a half-life of distribution and elimination equal to 3.3 and 50.0 min, respectively. Biodistribution and scintigraphic images showed high uptake in organs of excretion (kidneys, liver, and intestine). It could be also noted that tumor uptake was higher than the muscle at all time points. Tumor-to-muscle ratio reaches ∼4.5 at 24 h after administration. Conclusion These findings suggest that 99mTc-Lapachol can be a potential diagnostic agent for breast tumors.

Single-walled carbon nanotubes (SWCNT) are raising interest in biomedical field, as a drug delivery system, due to their large payload capacity and rich surface chemistry that allows attaching molecules. Generally, carbon nanotubes, without any surface modifications are cytotoxic to certain mammalian cells. However, after their functionalization, they become biocompatible and non-immunogenic. Thus, the aim of this work was to evaluate the effect of functionalization groups on the biocompatibility of SWCNT in vitro, as well as on its biodistribution in tumor-bearing mice. In this approach, carboxylate and bisphosphonate functionalized SWCNT were successfully synthesized and characterized by Raman, FTIR, and TGA techniques. The in vitro cytotoxicity against HEK-293 cells, and hemolysis assay were carried out and the results revealed important biocompatibility profile for both functionalized nanotubes. Furthermore, both types of SWCNT were successful radiolabeled with technetium-99 m, and biodistribution studies were conducted in Ehrlich tumor-bearing Swiss mice, showing higher tumor uptake by bisphosphonated SWCNT compared to carboxylated nanotubes. Moreover, acute toxicity study was performed in healthy Swiss mice revealing that none of the nanotubes displayed hematological, hepatic or renal toxicity. From all obtained results, the bisphosphonate functionalized SWCNT can be considered a plausible and alternative drug delivery platform for theranostic and therapeutics purposes.

Nanostructured polymer blends exhibit better properties over bulk polymeric blends and their homopolymers since several properties, such as stability, tensile strength, ductility, transparency, cre...

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior To associate paclitaxel (PTX) with doxorubicin (DXR) is one of the main chemotherapy strategies for breast cancer (BC) management. Despite the high response rates for this combination, it presents a cardiotoxic synergism, attributed to pharmacokinetic interactions between PTX and both DXR and its metabolite, doxorubicinol. One of the main strategies to minimize the cardiotoxicity of the combination is to extend the interval of time between DXR and PTX administration. However, it has been previously suggested that their co-administration leads to better efficacy compared to their sequential administration. In the present study, we investigated different molar ratio combinations of PTX:DXR (10:1; 1:1, and 1:10) against the 4T1 murine breast cancer cell line and concluded that there is no benefit of enhancing PTX concentration above that of DXR on the combination. Therefore, we obtained a long-circulating and fusogenic liposomal formulation co-encapsulating PTX and DXR (LCFL-PTX/DXR) at a molar ratio of 1:10, respectively, which maintained the in vitro biological activity of the combination. This formulation was investigated for its antitumor activity and toxicity in Balb/c mice bearing 4T1 breast tumor, and compared to treatments with free PTX, free DXR, and the mixture of free PTX:DXR at 1:10 molar ratio. The higher tumor inhibition ratios were observed for the treatments with free and co-encapsulated PTX:DXR in liposomes (66.87 and 66.52%, respectively, P>0.05) as compared to the control. The great advantage of the treatment with LCFL-PTX/DXR was its improved cardiac toxicity profile. While degeneration was observed in the hearts of all animals treated with the free PTX:DXR combination, no signs of cardiac toxicity were observed for animals treated with the LCFL-PTX/DXR. Thus, LCFL-PTX/DXR enables the co-administration of PTX and DXR, and might be considered valuable for breast cancer management. Associar paclitaxel (PTX) à doxorrubicina (DXR) é uma das principais estratégias de quimioterapia para o manejo do câncer de mama (CM). Apesar das altas taxas de resposta para esta combinação, ela apresenta um sinergismo cardiotóxico, atribuído às interações farmacocinéticas entre PTX e DXR e seu metabólito, doxorrubicinol. Uma das principais estratégias para minimizar a cardiotoxicidade da combinação é prolongar o intervalo de tempo entre a administração de DXR e PTX. No entanto, foi previamente sugerido que a sua co-administração conduz a uma melhor eficácia em comparação com a sua administração sequencial. No presente estudo, investigamos diferentes combinações de razões molares de PTX:DXR (10:1; 1:1 e 1:10) contra a linhagem celular de câncer de mama murino 4T1 e concluímos que não há benefício de aumentar a concentração de PTX acima dessa de DXR na combinação. Portanto, obtivemos uma formulação lipossômica fusogênica de longa circulação e co-encapsulamento de PTX e DXR (LCFL-PTX/DXR) em uma razão molar de 1:10, respectivamente, que manteve a atividade biológica in vitro da combinação. Esta formulação foi investigada quanto à sua atividade antitumoral e toxicidade em camundongos Balb/c com tumor de mama 4T1, e comparada aos tratamentos com PTX livre, DXR livre e a mistura de PTX livre:DXR na razão molar de 1:10. As maiores razões de inibição tumoral foram observadas para os tratamentos com PTX:DXR livre e co-encapsulado em lipossomas (66,87 e 66,52%, respectivamente, P>0,05) em relação ao controle. A grande vantagem do tratamento com LCFL-PTX/DXR foi a melhora do perfil de toxicidade cardíaca. Enquanto a degeneração foi observada nos corações de todos os animais tratados com a combinação PTX:DXR livre, nenhum sinal de toxicidade cardíaca foi observado para os animais tratados com o LCFL-PTX/DXR. Assim, LCFL-PTX/DXR permite a coadministração de PTX e DXR e pode ser considerado valioso para o tratamento do câncer de mama.

Liposomes have become successful nanostructured systems used in clinical practices. These vesicles are able to carry important drug loadings with noteworthy stability. The aim of this work was to develop iron oxide-loaded stealth liposomes as a prospective alternative for the treatment of lung cancer. In this study, citric acid iron oxide nanoparticles (IONPs-Ac) were synthesized and encapsulated in stealth liposomes. Their cytotoxicity and selectivity against lung tumor cells were assessed. Stealth liposomal vesicles, with relevant content of IONPs-Ac, named ferri–liposomes (SL-IONPs-Ac), were produced with an average size of 200 nm. They displayed important cytotoxicity in a human lung cancer cells model (A549 cells), even at low concentrations, whereas free IONPs-Ac displayed adequate biocompatibility. Nevertheless, the treatment at the same concentration of ferri–liposomes against HEK-293 cells, a normal human cell lineage, was not significantly cytotoxic, revealing a probable lung tumor selectiveness of the fabricated formulation. Furthermore, from the flow cytometry studies, it was possible to infer that ferri–liposomes were able to induce A549 tumor cells death through apoptosis/ferroptosis processes, evidenced by a significant reduction of the mitochondrial membrane potential.

Lapachol (LAP) is a natural compound with various biological properties, including anticancer activity. However, its clinical application is limited due to the low aqueous solubility and potential adverse side effects. Nanoemulsions are drug delivery systems that can assist in the administration of hydrophobic drugs, increasing their bioavailability and protecting from degradation. Thus, this study aimed to prepare a LAP-loaded nanoemulsion (NE-LAP), and evaluate its antitumor activity. For this purpose, the nanoemulsion was prepared using a hot homogenization method and characterized morphologically by cryogenic transmission electron microscopy (cryo-TEM). Mean diameter, polydispersity index, and zeta potential was evaluated by DLS, encapsulation efficiency was measured by HPLC. Moreover, the short-term storage stability, the drug release and hemolysis in vitro was determined. Additionally, pharmacokinetic, toxicology and toxicity properties of99mTc-NE-LAP were evaluated in a breast cancer (4T1) tumor model. The cryo-TEM showed spherical globules, and the physicochemical characterization of NE-LAP showed a homogeneous stable nanoemulsion with a mean diameter of ∼170 nm, zeta potential of around −20 mV, and encapsulation greater than 85 %. In vitro studies validated that encapsulation did not impair the cytotoxicity activity of LAP. The nanoemulsion was successfully radiolabeled and 99mTc-NE-LAP showed prolonged blood circulation and tumor affinity was confirmed by tumor-to-muscle ratio. Moreover, NE-LAP showed higher antitumor activity than the free drug and the treatment did not result in any signs of toxicity. Therefore, these findings suggest that NE-LAP can be considered an effective strategy for cancer treatment.

Since the discovery of the kahalalide family of marine depsipeptides in 1993, considerable work has been done to develop these compounds as new and biologically distinct anti-cancer agents. Clinical trials and laboratory research have yielded a wealth of data that indicates tolerance of kahalalides in healthy cells and selective activity against diseased cells. Currently, two molecules have attracted the greates level of attention, kahalalide F (KF) and isokahalalide F (isoKF, Irvalec, PM 02734, elisidepsin). Both compounds were originally isolated from the sarcoglossan mollusk Elysia rufescens but due to distinct structural characteristics it has been hypothesized and recently shown that the ultimate origin of the molecules is microbial. The search for their true source has been a subject of considerable research in the anticipation of finding new analogs and a culturable expression system that can produce sufficient material through fermentation to be industrially relevant.

Doxorubicin (DOX) is widely used in cancer treatment, however, its use is often limited due to its side effects. To avoid these shortcomings, the encapsulation of DOX into nanocarriers has been suggested. Herein, we proposed a novel nanostructured lipid carrier (NLC) formulation loading DOX, docosahexaenoic acid (DHA), and α-tocopherol succinate (TS) for cancer treatment. DHA is an omega-3 fatty acid and TS is a vitamin E derivative. It has been proposed that these compounds can enhance the antitumor activity of chemotherapeutics. Thus, we hypothesized that the combination of DOX, DHA, and TS in NLC (NLC-DHA-DOX-TS) could increase antitumor efficacy and also reduce toxicity. NLC-DHA-DOX-TS was prepared using emulsification-ultrasound. DOX was incorporated after preparing the NLC, which prevented its degradation during manufacture. High DOX encapsulation efficiency was obtained due to the ion-pairing with TS. This ion-pairing increases lipophilicity of DOX and reduces its crystallinity, contributing to its encapsulation in the lipid matrix. Controlled DOX release from the NLC was observed in vitro, with increased drug release at the acidic environment. In vitro cell studies indicated that DOX, DHA, and TS have synergistic effects against 4T1 tumor cells. The in vivo study showed that NLC-DHA-DOX-TS exhibited the greatest antitumor efficacy by reducing tumor growth in 4T1 tumor-bearing mice. In addition, this formulation reduced mice mortality, prevented lung metastasis, and decreased DOX-induced toxicity to the heart and liver, which was demonstrated by hematologic, biochemical, and histologic analyses. These results indicate that NLC-DHA-DOX-TS may be a promising carrier for breast cancer treatment.

Paclitaxel (PTX) has a great clinical significance as an antitumor drug, although several side effects are strongly dose-limiting. In this way, we prepared a PTX-loaded 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] polymeric micelles (PM/PTX) in an attempt to improve safety and effectiveness of conventional PTX formulation (CrEL/EtOH/PTX). In this study, we evaluated from both formulations: stability after dilution, hemocompatibility, cellular uptake, acute toxicity in healthy mice, antitumor activity, and toxicity after multiple-dose treatment. PM/PTX appeared to be more stable than CrEL/EtOH/PTX after dilution. PM/PTX did not exhibit hemolytic activity (values

5-Fluorouracil (5-FU) is an antineoplastic drug that causes, as a side effect, intestinal mucositis, acute inflammation in the small bowel. The Heat Shock Protein (Hsp) are highly expressed in inflammatory conditions, developing an important role in immune modulation. Thus, they are potential candidates for the treatment of inflammatory diseases. In the mucositis mouse model, the present study aimed to evaluate the beneficial effect of oral administration of milk fermented by Lactobacillus delbrueckii CIDCA 133 (pExu:hsp65), a recombinant strain. This approach showed increased levels of sIgA in the intestinal fluid, reducing inflammatory infiltrate and intestinal permeability. Additionally, the histological score was improved. Protection was associated with a reduction in the gene expression of pro-inflammatory cytokines such as Tnf, Il6, Il12, and Il1b, and an increase in Il10, Muc2, and claudin 1 (Cldn1) and 2 (Cldn2) gene expression in ileum tissue. These findings are corroborated with the increased number of goblet cells, the electronic microscopy images, and the reduction of intestinal permeability. The administration of milk fermented by this recombinant probiotic strain was also able to reverse the high levels of gene expression of Tlrs caused by the 5-FU. Thus, the rCIDCA 133:Hsp65 strain was revealed to be a promising preventive strategy for small bowel inflammation.

The drugs currently used to treat leishmaniases have limitations concerning cost, efficacy, and safety, making the search for new therapeutic approaches urgent. We found that the gold(I)-derived complexes were active against L. infantum and L. braziliensis intracellular amastigotes with IC50 values ranging from 0.5 to 5.5 μM. All gold(I) complexes were potent inhibitors of trypanothione reductase (TR), with enzyme IC50 values ranging from 1 to 7.8 μM. Triethylphosphine-derived complexes enhanced reactive oxygen species (ROS) production and decreased mitochondrial respiration after 2 h of exposure, indicating that gold(I) complexes cause oxidative stress by direct ROS production, by causing mitochondrial damage or by impairing TR activity and thus accumulating ROS. There was no cross-resistance to antimony; in fact, SbR (antimony-resistant mutants) strains were hypersensitive to some of the complexes. BALB/c mice infected with luciferase-expressing L. braziliensis or L. amazonensis and treated orally with 12.5 mg/kg/day of AdT Et (3) or AdO Et (4) presented reduced lesion size and parasite burden, as revealed by bioimaging. The combination of (3) and miltefosine allowed for a 50% reduction in miltefosine treatment time. Complexes 3 and 4 presented favorable pharmacokinetic and toxicity profiles that encourage further drug development studies. Gold(I) complexes are promising antileishmanial agents, with a potential for therapeutic use, including in leishmaniasis caused by antimony-resistant parasites.

Made available in DSpace on 2021-06-25T11:04:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01 Mucoadhesive polymeric nanocapsules have attracted interest of researchers from different fields from natural sciences because of their ability to interact with the mucosa and increase drug permeation. Anesthesia by immersion causes absorption through the skin and gills of fish, so it is important to evaluate the exposure of these organs to drug nanosystems. Benzocaine (BENZ) is one of the most popular anesthetic agents used in fish anesthesia, but it has drawbacks because of its low bioavailability, resulting in weak absorption after immersion. Here we describe method developed for preparing and characterizing chitosan-coated PLGA mucoadhesive nanoparticles containing BENZ (NPMAs) for zebrafish immersion anesthesia. We determined the lowest effective concentration, characterized the interaction of the mucoadhesive system with fish, measured the anesthetic efficacy, and evaluated possible toxic effects in embryos and adults exposed to the nanoformulations. This study opens perspectives for using nanoformulations prepared with BENZ in aquaculture, allowing reduction of dosage as well as promoting more effective anesthesia and improved interaction with the mucoadhesive system of fish. Department of Pharmacology University of São Paulo-ICB/USP Laboratório Integrado de Biociências Translacionais (LIBT) Instituto de Biodiversidade e Sustentabilidade (NUPEM) Universidade Federal do Rio de Janeiro (UFRJ) Department of Morphology ICB-UFMG Aquiculture Laboratory (Laqua) UFMG Department of Preventive Veterinary Medicine São Paulo State University Department of Postgraduate in Health Sciences PROCISA Federal University of Roraima (UFRR) Institute of Chemistry São Paulo State University (Unesp) Laboratory of Animal Pharmacology and Toxicology Brasil University Department of Clinical and Toxicological Analyses Faculty of Pharmacy-UFMG Laboratory of Applied Immunology Federal University of São Carlos School of Veterinary Medicine Department of Clinic and Veterinary Surgery UFMG Faculty of Medicine São Leopoldo Mandic Institute of Science and Technology of Sorocaba São Paulo State University Department of Preventive Veterinary Medicine São Paulo State University Institute of Chemistry São Paulo State University (Unesp) Institute of Science and Technology of Sorocaba São Paulo State University

Scorpion sting envenoming impacts millions of people worldwide, with cardiac effects being one of the main causes of death on victims. Here we describe the first Ca2+ channel toxin present in Tityus serrulatus (Ts) venom, a cell penetrating peptide (CPP) named CPP-Ts. We show that CPP-Ts increases intracellular Ca2+ release through the activation of nuclear InsP3R of cardiomyocytes, thereby causing an increase in the contraction frequency of these cells. Besides proposing a novel subfamily of Ca2+ active toxins, we investigated its potential use as a drug delivery system targeting cancer cell nucleus using CPP-Ts’s nuclear-targeting property. To this end, we prepared a synthetic CPP-Ts sub peptide14–39 lacking pharmacological activity which was directed to the nucleus of specific cancer cell lines. This research identifies a novel subfamily of Ca2+ active toxins and provides new insights into biotechnological applications of animal venoms.

Protein-polymer conjugates have achieved tremendous attention in the last few years, since their importance in diverse fields including drug delivery, biotechnology and nanotechnology. Over the past few years, numerous chemical strategies have been developed to conjugate different synthetic polymers onto proteins and great progress has been made. Currently, there are a handful of therapeutic polymer conjugates that have been approved by the FDA, while many hundreds of products are under extensive clinical trials and preclinical development phases. In this way, the development of novel techniques for conjugation, especially living radical polymerisation (LRP) has greatly enhanced the potential to broaden the scope of therapeutic conjugates. As a consequence, versatile techniques have developed, such as the 'grafting from' approach, which allows modifications of biomacromolecules at the atomic level, and subsequently preparing well-defined stimuli-responsive conjugates. These strategies present a unique perspective for therapy expansion of a new generation of 'smart' products with proprieties that can be finely controlled and tuned rather than just enhanced. This article highlights recent advances in the synthesis and application of protein-polymer conjugates by controlled radical polymerisation techniques, with special emphasis on stimuli-responsive conjugates on new applications in biomedical and pharmaceutical areas.

Nanocarriers combining two or more different approaches in the same particle has been a new trend in research worldwide. Among the strategies studied, magnetic nanoparticles with dual properties related to drug delivery and diagnostic imaging represent a significant improvement in the response of chemotherapy and in a real-time monitoring of drug distribution. Nanocarriers combining dual properties such as thermal and magnetic, enable controlling the release and modulate a treatment giving more specificity of action. This is possible since a magnetic external field can allow the adequate movement of nanoparticles and provide a means to remotely heating the target tissue safely. The temperature increase can trigger changes in the structure of nanocarriers leading to the release of drugs. This field of study known as magnetic fluid hyperthermia (MFH), currently in order to improve the selective heating process has been used superparamagnetic nanostructured, mainly made up of iron oxide, coated or encapsulated in, mostly, polymeric nanoparticles. In this way, this review aims to provide an updated review of the state of art of nanostructured systems that combines simultaneously magnetic hyperthermia and thermal properties in the preclinical level investigation.

Polymeric micelles (PM) are versatile nanoparticles with suitable properties to tumor delivery of hydrophobic drugs such as paclitaxel (PTX) and imaging probes such as technetium-99 m. However, instability of drug content in aqueous medium and obstacles related to lengthy radiolabeling procedures, high radiation exposure and risk of human error limit its clinical application. Freeze-dried kit formulation might be a strategy to overcome these issues. Thus, we developed a freeze-dried kit formulation containing diethylenetriaminepentaacetic acid (DTPA)-functionalized 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] polymeric micelles carrying PTX (PM-DTPA/PTX) for application in the diagnosis and/or treatment of solid tumors. PM-DTPA/PTX were prepared and the physical and radiochemical characteristics (size, zeta potential, PTX content and radiolabeling yields) evaluated before lyophilization process and after storage up to 180 days. In vivo biodistribution studies were performed in 4T1 breast tumor-bearing BALB/c mice. A freeze-dried kit containing PM-DTPA/PTX showed high storage stability in all parameters evaluate up to 180 days since no significant alteration was observed at all evaluated timeframes. The freeze-drying process did not change the physicochemical and biological properties of the PM, including the property of tumor targeting. Therefore, a stable freeze-dried kit containing PM-DTPA/PTX was developed as an easy and fast preparation and showed high potential for theranostic application in cancer treatment.

Doxorubicin (DOX) is widely used in cancer treatment, however, the use of this drug is often limited due to its cardiotoxic side effects. In order to avoid these adverse effects, the encapsulation of DOX into nanosystems has been used in the last decades. In this context, pH-sensitive liposomes have been shown promising for delivering cytotoxic agents into tumor cells, however, the lack of information about in vivo toxicity of this nanocarrier has impaired translational studies. Therefore, the aim of this work was to investigate the acute toxicity and cardiotoxicity of DOX-loading pH-sensitive liposomes (SpHL-DOX). To achieve this, female BALB/c mice, after intravenous administration, were monitored by means of clinical, laboratory, histopathological and electrocardiographic (ECG) analyses. Results indicate that SpHL was able to prevent renal toxicity and the hepatic injury was less extensive than free DOX. In addition, lower body weight loss was associated with less ECG QT interval prolongation to animals receiving SpHL-DOX (14.6 ± 5.2%) compared to animals receiving free DOX (35.7 ± 4.0%) or non-pH-sensitive liposomes (nSpHL-DOX) (47.0 ± 9.8%). These results corroborate with SpHL-DOX biodistribution studies published by our group. In conclusion, the SpHL-DOX showed less toxic effects on mice compared to free DOX or nSpHL-DOX indicating that SpHL-DOX is a promising strategy to reduce the serious cardiotoxic effects of DOX.

A long-circulating and pH-sensitive liposome containing paclitaxel (SpHL-PTX) was recently developed by our group. Once in an acidic environment, for example, tumors, these liposomes undergo destabilization, releasing the encapsulated drug. In this way, the aim of this study was to evaluate the molecular and supramolecular interactions between the lipid bilayer and PTX in similar biological environment conditions. High-sensitivity analyses of SpHL-PTX structures were obtained by the small-angle X-ray scattering technique combined with other techniques such as dynamic light scattering, asymmetric flow field-flow fractionation, transmission electron microscopy, and high-performance liquid chromatography. The results showed that PTX incorporation in the liposomal bilayer clearly leads to changes in supramolecular organization of dioleoylphosphatidylethanolamine (DOPE) molecules, inducing the formation of more ordered structures. Changes in supramolecular organization were observed at lower pH, indicating that pH sensitivity was preserved even in the presence of fetal bovine serum proteins. Furthermore, morphological and physicochemical characterization of SpHL-PTX evidenced the formation of nanosized dispersion suitable for intravenous administration. In conclusion, a stable nanosized dispersion of PTX was obtained at pH 7.4 with suitable parameters for intravenous administration. At lower pH conditions, the pH sensitivity of the system was clearly evidenced by changes in the supramolecular organization of DOPE molecules, which is crucial for the delivery of PTX into the cytoplasm of the targeted cells. In this way, the results obtained by different techniques confirm the feasibility of SpHL as a promising tool to PTX delivery in acidic environments, such as tumors.

Angiogenesis, the complex process of formation of new blood vessels from pre-existing blood vessels, which involves the participation of several pro- and anti-angiogenic factors, is implicated in many physiological and pathological conditions. Nanoparticle-based anti-angiogenic activity at the tumour tissue, harnessed by the Enhanced Permeability and Retention Effect (EPR effect), could potentially become a breakthrough therapy to halt tumour progression. Herein, we evaluate the anti-angiogenic effect of ZnWO4 nanoparticles (NPs). The nanoparticles were obtained by microwave-assisted hydrothermal synthesis (MAHS) at 120 °C for 60 min and were structurally characterised by X-ray diffraction (XRD) and micro-Raman (MR) spectroscopy. The mean size and polydispersity index were estimated by Zeta potential analysis. The XRD analysis revealed structural organisation at a long-range order, with an average crystallite size of around 3.67 nm, while MR revealed short-range order for ZnWO4. The anti-angiogeni...

A range of antitumor agents for cancer treatment is available; however, they show low specificity, which often limit their use. Recently, we have reported the preparation of folate-coated long-circulating and pH-sensitive liposomes (SpHL-folate-PTX) loaded with paclitaxel (PTX), an effective drug for the treatment of solid tumors, including breast cancer. The purpose of this study was to prepare and characterize SpHL-PTX and SpHL-folate-PTX radiolabeled with technetium–99 m (99mTc). Biodistribution studies and scintigraphic images were performed after intravenous administration of 99mTc-PTX, 99mTc-SpHL-PTX and 99mTc-SpHL-folate-PTX into healthy and tumor-bearing mice. High radiochemical purity (> 98%) and in vitro stability (> 90%) were achieved for both liposome formulations. The pharmacokinetic properties of 99mTc-SpHL-DTPA-PTX and 99mTc-SpHL-folate-DTPA-PTX decreased in a monophasic manner showing half-life of 400.1 and 541.8 min, respectively. Scintigraphic images and biodistribution studies showed a significant uptake in liver, spleen and kidneys, demonstrating these routes as way for excretion. At 8 h post-injection, the liposomal tumor uptake was higher than 99mTc-PTX. Interesting, 4 h after administration, the liposome folate coated showed higher tumor-to-muscle ratio than 99mTc-SpHL-DTPA-PTX and 99mTc-PTX. In conclusion, the liposomal systems, showed high tumor uptake by scintigraphic images, especially the 99mTc-SpHL-folate-DTPA-PTX that showed a sustained and higher tumor-to-muscle ratio than non-functionalized liposome, which indicate its feasibility as a PTX delivery system to folate positive tumors.

Gadodiamide (Gd-DTPA-BMA) is a gadolinium-based complex, used as a contrast agent in magnetic resonance imaging procedures. Recent studies revealed the capacity of this complex of inducing apoptosis in neoplastic cells. However, a great challenge for its use as an anticancer drug is low cellular internalization and drug delivery systems such as thermosensitive liposomes can be a strategy to overcome these limitations and increase anti-tumor efficacy. In this context, this study aimed to develop, characterize, and assess the cytotoxic activity and selectivity index of thermosensitive liposomes containing Gd-DTPA-BMA. Formulations were prepared by the lipid film hydration method and their physicochemical, morphological, and thermal properties were evaluated. Cell viability was performed 4T1/MDA-MB-231 tumor cells and WI-26 VA4 normal cells. Transmission electron microscopy analyses showed high electron density in the inner core of Gd-DTPA-BMA-loaded liposomes that can be attributed to the Gd-DTPA-BMA, since Gd-loaded nanosystems present low light transmittance and high electron density by this technique. The dynamic light scattering, differential scanning calorimetry, small-angle X-ray scattering, and in vitro release results confirm that the lipid composition was suitable since Tc (temperature of the transition Lβ → Lα) values are in accordance with those reported for thermosensitive liposomes used in the treatment of cancer. The cytotoxic studies against breast cancer cell lines demonstrated that the Gd-DTPA-BMA-loaded liposomes have higher cytotoxicity than free Gd-DTPA-BMA. Moreover, these liposomes presented minimal toxicity in a normal cell line when compared to the free Gd-DTPA-BMA. Therefore, the results of this study suggest that thermosensitive liposomes containing Gd-DTPA-BMA might be a new promising nanocarrier system for breast cancer treatment.

Statins, typically used to reduce lipid levels, have been rediscovered for exhibiting anticancer activities. Among them, especially simvastatin may influence the proliferation, migration, and survival of cancer cells. The concept of using statins to treat cancer has been adopted since the 1990s In vitro and in vivo experiments and cohort studies using statins have been carried out to demonstrate their antitumor effects (such as proliferation and migration impairment) by influencing inflammatory and oxidative stress-related tumorigenesis. Nevertheless, the biological mechanisms for these actions are not fully elucidated. In this review, we present an overview of the most important studies conducted from 2015 to date on the use of simvastatin in cancer therapy. This review brings the most recent perspectives and targets in epidemiological, in vitro, and in vivo studies, regarding the use of simvastatin alone or in combination with other drugs for the treatment of various types of cancer.

The COVID-19 has become of striking interest since the number of deaths is constantly rising all over the globe, and the search for an efficient treatment is more urgent. In light of this worrisome scenario, this opinion review aimed to discuss the current knowledge about the potential role of curcumin and its nanostructured systems on the SARS-CoV-2 targets. From this perspective, this work demonstrated that curcumin urges as a potential antiviral key for the treatment of SARS-CoV-2 based on its relation to the infection pathways. Moreover, the use of curcumin-loaded nanocarriers for increasing its bioavailability and therapeutic efficiency was highlighted. Additionally, the potential of the nanostructured systems by themselves and their synergic action with curcumin on molecular targets for viral infections have been explored. Finally, a viewpoint of the studies that need to be carried out to implant curcumin as a treatment for COVID-19 was addressed., Graphical Abstract ga1

Staphylococcus aureus is a specie of great medical importance associated with many infections as bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device related infections. Early identification of infectious foci is crucial for successful treatment. Scintigraphy could contribute to this purpose since specific radiotracers were available. Aptamers due to their high specificity have great potential for radiopharmaceuticals development. In the present study scintigraphic images of S. aureus infectious foci were obtained using specific S. aureus aptamers radiolabeled with 99mTc.

Uncontrolled angiogenesis is directly associated with ocular diseases such as macular degeneration and diabetic retinopathy. Implantable polymeric drug delivery systems have been proposed for intravitreal applications and in the present work, we evaluated the antiangiogenic potential of PLGA ocular implants loaded with the triterpene lupeol using in vitro and in vivo models. The drug/polymer physiochemical properties of the lupeol-loaded PLGA were validated as functionally similar using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Interestingly, in an in vitro culture system, lupeol (100 μg/mL and 250 μg/mL) was capable to inhibited the proliferation as well as the migration of Human Umbilical Vein Endothelial Cells (HUVEC), without interfering in cell viability, promoting a significant reduction in the percentage of vessels (39.41% and 44.12%, respectively), compared with the control group. In vivo test, by using the chorioallantoic membrane (CAM) model, lupeol-loaded PLGA ocular implants showed antiangiogenic activity comparable to the FDA-approved anti-VEGF antibody Bevacizumab. Overall, our results suggest lupeol-loaded PLGA ocular implants were able to inhibit the angiogenic process by impairing both proliferation and migration of endothelial cells.

Despite efforts, cancer is still one of the leading causes of morbidity and mortality worldwide, with approximately 14 million new cases and 8.2 million cancer-related deaths each year, according to the World Health Organization. Among the strategies to reduce cancer progression and improving its management, implementing early detection technologies is crucial. Based on the fact that several types of cancer cells overexpress surface receptors, small molecule ligands, such as peptides, have been developed to allow tumor identification at earlier stages. Allied with imaging techniques such as PET and SPECT, radiolabeled peptides play a pivotal role in nuclear medicine. Bombesin, a peptide of 14 amino acids, is an amphibian homolog to the mammalian gastrin-releasing peptide (GRP), that has been extensively studied as a targeting ligand for diagnosis and therapy of GRP positive tumors, such as breast, pancreas, lungs and prostate cancers. In this context, herein we provide a review of reported bombesin derivatives radiolabeled with a multitude of radioactive isotopes for diagnostic purposes in the preclinical setting. Moreover, since animal models are highly relevant for assessing the potential of clinical translation of this radiopeptides, a brief report of the currently used GRP-positive tumor-bearing animal models is described.

Long circulating pH-sensitive liposomes have been shown to effectively deliver doxorubicin (DOX) to tumors and reduce its toxic effects. Folic acid receptors are upregulated in a wide variety of solid, epithelial tumors, including breast cancer. In order to improve liposomal endocytosis and antitumor activity, folic acid has been added to nanoparticles surfaces to exploit overexpression of folate receptors in tumor cells. The purpose of this study was to evaluate the antitumor activity in vitro and in vivo of long circulating pH-sensitive folate-coated DOX-loaded liposomes (SpHL-DOX-Fol) in a 4T1 breast cancer model system in vitro and in vivo. Biodistribution studies were performed and in vivo electrocardiographic parameters were evaluated. A higher tumor uptake for radiolabeled SpHL-Fol (99mTc-SpHL-Fol) 4 h after intravenous administration was observed in comparision with non-folate-coated liposomes (99mTc-SpHL). Antitumor activity showed that SpHL-DOX-Fol treatment led to a 68% growth arrest and drastically reduce pulmonary metastasis foci. Additionally, eletrocardiographic parameters analysis revealed no dispersion in the QT and QTc interval was observed in liposomal treated mice. In summary, this novel multifunctional nanoplatform deomonstrated higher tumor uptake and antitumor activity. SpHL-DOX-Fol represents a drug delivery platform to improve DOX tumor delivery and reduce dose-limiting toxicity.

5-fluorouracil (5-FU) is an anticancer drug, which inhibits human thymidine phosphorylase (hTP) and plays a key role in maintaining the process of DNA replication and repair. It is involved in regulating pyrimidine nucleotide production, by which it inhibits the mechanism of cell proliferation and cancerous tumor growth. However, up to 80% of the administered drug is metabolized by dihydropyrimidine dehydrogenase (DPD). This work compares binding of 5-FU and its analogues to hTP and DPD, and suggests strategies to reduce drug binding to DPD to decrease the required dose of 5-FU. An important feature between the proteins studied here was the difference of charge distribution in their binding sites, which can be exploited for designing drugs to selectively bind to the hTP. The 5-FU presence was thought to be required for a closed conformation. Comparison of the calculation results pertaining to unliganded and liganded protein showed that hTP could still undergo open-closed conformations in the absence of the ligand; however, the presence of a positively charged ligand better stabilizes the closed conformation and rigidifies the core region of the protein more than unliganded or neutral liganded system. The study has also shown that one of the three hinge segments linking the two major α and α/β domains of the hTP is an important contributing factor to the enzyme's open-close conformational twist during its inactivation-activation process. In addition, the angle between the α/β-domain and the α-domain has shown to undergo wide rotations over the course of MD simulation in the absence of a phosphate, suggesting that it contributes to the stabilization of the closed conformation of the hTP.

Background The hyaluronidase enzyme is generally known as a spreading factor in animal venoms. Although its activity has been demonstrated in several organisms, a deeper knowledge about hyaluronidase and the venom spreading process from the bite/sting site until its elimination from the victim's body is still in need. Herein, we further pursued the goal of demonstrating the effects of inhibition of T. serrulatus venom (TsV) hyaluronidase on venom biodistribution. Methods and principal findings We used technetium-99m radiolabeled Tityus serrulatus venom (99mTc-TsV) to evaluate the venom distribution kinetics in mice. To understand the hyaluronidase’s role in the venom’s biodistribution, 99mTc-TsV was immunoneutralized with specific anti-T.serrulatus hyaluronidase serum. Venom biodistribution was monitored by scintigraphic images of treated animals and by measuring radioactivity levels in tissues as heart, liver, lungs, spleen, thyroid, and kidneys. In general, results revealed that hyaluronidase inhibition delays venom components distribution, when compared to the non-neutralized 99mTc-TsV control group. Scintigraphic images showed that the majority of the immunoneutralized venom is retained at the injection site, whereas non-treated venom is quickly biodistributed throughout the animal’s body. At the first 30 min, concentration peaks are observed in the heart, liver, lungs, spleen, and thyroid, which gradually decreases over time. On the other hand, immunoneutralized 99mTc-TsV takes 240 min to reach high concentrations in the organs. A higher concentration of immunoneutralized 99mTc-TsV was observed in the kidneys in comparison with the non-treated venom. Further, in situ neutralization of 99mTc-TsV by anti-T.serrulatus hyaluronidase serum at zero, ten, and 30 min post venom injection showed that late inhibition of hyaluronidase can still affect venom biodistribution. In this assay, immunoneutralized 99mTc-TsV was accumulated in the bloodstream until 120 or 240 min after TsV injection, depending on anti-hyaluronidase administration time. Altogether, our data show that immunoneutralization of hyaluronidase prevents venom spreading from the injection site. Conclusions By comparing TsV biodistribution in the absence or presence of anti-hyaluronidase serum, the results obtained in the present work show that hyaluronidase has a key role not only in the venom spreading from the inoculation point to the bloodstream, but also in venom biodistribution from the bloodstream to target organs. Our findings demonstrate that hyaluronidase is indeed an important spreading factor of TsV and its inhibition can be used as a novel first-aid strategy in envenoming., Author summary Hyaluronidases are known as the venom components responsible for disseminating toxins from the injection site to the victim’s organism. Therefore, understanding how the venom distribution occurs and the role of hyaluronidases in this process is crucial in the field of toxinology. In this study, we inhibited Tityus serrulatus venom (TsV) hyaluronidase’s action using specific anti-Ts-hyaluronidase antibodies. Labeling TsV with a radioactive compound enabled monitoring of its biodistribution in mice. Our results show that, upon hyaluronidase inhibition, TsV remains at the injection site for longer, and only a reduced amount of the venom reaches the bloodstream. Consequently, the venom arrives later at target organs like the heart, liver, lungs, spleen, and thyroid. Considering the possible application of hyaluronidase inhibition as a therapeutic resource in envenoming first-aid treatment, we performed the administration of hyaluronidase neutralizing antibodies at different times after TsV injection. We observed that TsV remains in the bloodstream and its arrival at tissues is delayed by 120 or 240 min after TsV injection, depending on anti-hyaluronidase administration times. Our data show that hyaluronidase plays a crucial role in TsV spreading from the injection site to the bloodstream and from the bloodstream to the organs, thus suggesting that its inhibition can help to improve envenoming’s treatment.

Liposomes are lipid vesicles widely used as nanocarriers in targeted drug delivery systems for therapeutic and/or diagnostic purposes. A strategy to prolong the blood circulation time of the liposomes includes the addition of a hydrophilic polymer polyethylene glycol (PEG) moiety onto the surface of the vesicle. Several studies claim that liposome PEGylation by a single chain length or a combination of PEG with different chain lengths may alter the liposomes’ pharmacokinetic properties. Therefore, the purpose of this study was to evaluate the influence of PEG on the biodistribution of pH-sensitive liposomes in a tumor-bearing animal model. Three liposomal formulations (PEGylated or not) were prepared and validated to have a similar mean diameter, monodisperse distribution, and neutral zeta potential. The pharmacokinetic properties of each liposome were evaluated in healthy animals, while the biodistribution and scintigraphic images were evaluated in tumor-bearing mice. High tumor-to-muscle ratios were not statistically different between the PEGylated and non-PEGylated liposomes. While PEGylation is a well-established strategy for increasing the blood circulation of nanostructures, in our study, the use of polymer coating did not result in a better in vivo profile. Further studies must be carried out to confirm the feasibility of the non-PEGylated pH-sensitive liposomes for tumor treatment.

Over the last decade, studies showed evidence of enhanced sensitivity of triple negative breast cancer (TNBC) to DNA-damaging agents, such as cisplatin (CIS), compared to other breast cancer subtypes. Despite its high efficacy, CIS has its use limited by dose-dependent side effects, mainly nephrotoxicity and neurotoxicity. In previous studies, it has been demonstrated by our research group that the encapsulation of CIS into pH-sensitive-PEGylated liposomes (pHPL-CIS) might allow to overcome some of its side effects. In the present work, we investigated the antitumor activity and toxicity of pHPL-CIS on Balb/c nude female mice bearing MDA-MB-231 tumor, a human TNBC cell line. Treatments with free-CIS or pHPL-CIS were both administered i.v. once a week for three weeks in cumulative doses of 12 and 30 mg/kg. Treatments in the higher dose allowed for similar tumor regression at the end of the experiment, however, the treatment with pHPL-CIS allowed for an earlier appearance of the antitumor effect. Additionally, animals receiving the higher dose of free-CIS presented weight loss, hepatic degeneration and 20% mortality rate, which was not observed for animals that received the high dose of pHPL-CIS. Thus, pHPL-CIS might be considered a promising candidate for the management of TNBC.

Doxorubicin (DOX) is an anthracycline antibiotic widely used in the treatment of cancer, however, it is associated with the occurrence of adverse reactions that limits its clinical use. In this context, the encapsulation of DOX in micelles responsive to pH variations has shown to be a strategy for tumor delivery of the drug, with the potential to increase therapeutic efficacy and to reduce the toxic effects. In addition, radiolabeling nanoparticles with a radioactive isotope is of great use in preclinical studies, since it allows the in vivo monitoring of the nanostructure through the acquisition of quantitative images. Therefore, this study aimed to develop, characterize, and evaluate the antitumor activity of a pH-sensitive micelle composed of DSPE-PEG2000, oleic acid, and DOX. The micelles had a diameter of 13 nm, zeta potential near to neutrality, and high encapsulation percentage. The critical micellar concentration (CMC) was 1.4 × 10−5 mol L-1. The pH-sensitivity was confirmed in vitro through a drug release assay. Cytotoxicity studies confirmed that the encapsulation of DOX into the micelles did not impair the drug cytotoxic activity. Moreover, the incorporation of DSPE-PEG2000-DTPA into the micelles allowed it radiolabeling with the technetium-99 m in high yield and stability, permitting its use to monitor antitumor therapy. In this sense, the pH-sensitive micelles were able to inhibit tumor growth significantly when compared to non-pH-sensitive micelles and the free drug. in vivo toxicity evaluation in the zebrafish model revealed significantly lower toxicity of pH-sensitive micelles compared to the free drug. These results indicate that the developed formulation presents itself as a promising alternative to potentiate the treatment of tumors.