Fusion of Tumor-Derived Exosomes with Long-Circulating and pH-Sensitive Liposomes Loaded with Doxorubicin for the Treatment of Breast Cancer.

Doxorubicin (DOX) is a chemotherapeutic agent that has been used in the treatment of breast cancer. However, serious toxic effects have limited its use, mainly cardiotoxicity. To minimize the adverse effects, liposomal preparations containing DOX have been developed. These preparations can reach the target in the tumor region as well as bypass the resistance-related problems. An alternative to increased therapeutic efficacy may be the fusion of liposomes with exosomes released from tumor cells to facilitate membrane and fusion interactions, achieving greater cell uptake. Thus, the purpose of this study was the fusion of exosomes derived from breast tumor cells with long-circulating and pH-sensitive liposomes loading DOX (ExoSpHL-DOX) for the treatment of breast cancer. The mean diameter of ExoSpHL-DOX was 100.8 ± 7.8 nm, the polydispersity index was 0.122 ± 0.004, and the encapsulated DOX content was equal to 83.5 ± 2.5%. The fusion of exosomes with long-circulating and pH-sensitive liposomes was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, and nano-flow cytometry. The physicochemical characteristics of ExoSpHL-DOX were maintained for 60 days, at 4 °C. The study of the release of DOX from ExoSpHL-DOX in dilution media with different pH values showed the pH sensitivity characteristic of the nanosystem, since 96.6 ± 0.2% of DOX was released from ExoSpHL-DOX at pH 5.0, while at pH 7.4, the release was 70.1 ± 1.7% in the medium. The cytotoxic study against the breast cancer cell line demonstrated that ExoSpHL-DOX treatment significantly reduced the cancer cell viability.

Long-circulating and fusogenic liposomes loaded with a glucoevatromonoside derivative induce potent antitumor response.

Cancer is an important public health problem, being one of the leading causes of death worldwide. Most antineoplastic agents cause severe toxic effects and some types of cancer do not respond or are resistant to the existing pharmacotherapy, necessitating the research and development of new therapeutic strategies. Cardenolides have shown significant antitumor activity due to their ability to inhibit the Na+K+ATPase enzyme, and the expression of this enzyme is increased in tumor cells. Glucoevatromonoside containing peracetylated glucose hydroxyl groups (GEVPG) is a cardenolide derivative that has low solubility in aqueous media, which constitutes a barrier to its potential biological applications. In this context, the use of liposomes represents a promising strategy to deliver GEVPG, thus allowing its intravenous administration. In this study, long-circulating and fusogenic liposomes containing GEVPG (SpHL-GEVPG) were developed, and their chemical and physicochemical properties were evaluated. SpHL-GEVPG presented adequate properties, including a mean diameter of 182.2 ± 2.7 nm, a polydispersity index equal to 0.36 ± 0.03, a zeta potential of -2.37 ± 0.31 mV, and a GEVPG entrapment of 0.38 ± 0.04 mg/mL. Moreover, this formulation showed a good stability after having been stored for 30 days at 4 °C. The cytotoxic studies against breast (MDA-MB-231, MCF-7, and SKBR-3) and lung (A549) cancer cell lines demonstrated that SpHL-GEVPG treatment significantly reduced the cell viability. In addition, the SpHL-GEVPG formulation presented a good selectivity toward these cancer cells. The evaluation of the therapeutic efficacy of the treatment with SpHL-GEVPG showed a potent anticancer effect in an A549 human lung cancer xenograft model. SpHL-GEVPG administered at doses of 1.0 and 2.0 mg/kg (i.v.) induced antitumor effect comparable to paclitaxel given at dose of 10 mg/kg (i.v.) to mice. Therefore, the results of the present work indicate the potential applicability of SpHL-GEVPG as a new anticancer formulation.

Neuropsicologia e oncologia pediátrica: um diálogo em emergência / Neuropsychology and oncology: an emerging dialogue

Dados do INCA estimam que anualmente cerca de 11.530 casos de neoplasias são diagnosticados em crianças e adolescentes. O aumento do número de sobreviventes vem crescendo, junto com as sequelas cognitivas decorrentes da doença e de seu tratamento. Nesse sentido, o presente artigo discute acerca da pertinência do estabelecimento de diálogo entre a neuropsicologia e a oncologia. O artigo aborda os dois subtipos de câncer mais comuns na infância e adolescência: os tumores de fossa posterior e a leucemia linfoide aguda. A discussão será ilustrada com resultados oriundos de dois estudos distintos realizados em serviços públicos de referência no tratamento do câncer pediátrico na Região Nordeste do Brasil (AU)

Highly efficient siRNA delivery system into human and murine cells using single-wall carbon nanotubes.

Development of RNA interference (RNAi) technology utilizing short interfering RNA sequences (siRNA) has focused on creating methods for delivering siRNAs to cells and for enhancing siRNA stability in vitro and in vivo. Here, we describe a novel approach for siRNA cellular delivery using siRNA coiling into carboxyl-functionalized single-wall carbon nanotubes (SWCNTs). The CNT-siRNA delivery system successfully demonstrates nonspecific toxicity and transfection efficiency greater than 95%. This approach offers the potential for siRNA delivery into different types of cells, including hard-to-transfect cells, such as neuronal cells and cardiomyocytes. We also tested the CNT-siRNA system in a non-metastatic human hepatocellular carcinoma cell line (SKHep1). In all types of cells used in this work the CNT-siRNA delivery system showed high efficiency and apparent no side effects for various in vitro applications.

Cardiac anti-remodelling effect of aerobic training is associated with a reduction in the calcineurin/NFAT signalling pathway in heart failure mice.

Cardiomyocyte hypertrophy occurs in response to a variety of physiological and pathological stimuli. While pathological hypertrophy in heart failure is usually coupled with depressed contractile function, physiological hypertrophy associates with increased contractility. In the present study, we explored whether 8 weeks of moderate intensity exercise training would lead to a cardiac anti-remodelling effect in an experimental model of heart failure associated with a deactivation of a pathological (calcineurin/NFAT, CaMKII/HDAC) or activation of a physiological (Akt-mTOR) hypertrophy signalling pathway. The cardiac dysfunction, exercise intolerance, left ventricle dilatation, increased heart weight and cardiomyocyte hypertrophy from mice lacking alpha(2A) and alpha(2C) adrenoceptors (alpha(2A)/alpha(2C)ARKO mice) were associated with sympathetic hyperactivity induced heart failure. The relative contribution of Ca(2+)-calmodulin high-affinity (calcineurin/NFAT) and low-affinity (CaMKII/HDAC) targets to pathological hypertrophy of alpha(2A)/alpha(2C)ARKO mice was verified. While nuclear calcineurin B, NFATc3 and GATA-4 translocation were significantly increased in alpha(2A)/alpha(2C)ARKO mice, no changes were observed in CaMKII/HDAC activation. As expected, cyclosporine treatment decreased nuclear translocation of calcineurin/NFAT in alpha(2A)/alpha(2C)ARKO mice, which was associated with improved ventricular function and a pronounced anti-remodelling effect. The Akt/mTOR signalling pathway was not activated in alpha(2A)/alpha(2C)ARKO mice. Exercise training improved cardiac function and exercise capacity in alpha(2A)/alpha(2C)ARKO mice and decreased heart weight and cardiomyocyte width paralleled by diminished nuclear NFATc3 and GATA-4 translocation as well as GATA-4 expression levels. When combined, these findings support the notion that deactivation of calcineurin/NFAT pathway-induced pathological hypertrophy is a preferential mechanism by which exercise training leads to the cardiac anti-remodelling effect in heart failure.

Lesoes produzidas por agentes quimicos nas industrias de galvanoplastia. / Injuries due to chemical agents in galvanoplastic industries

O presente artigo apresenta uma descricao das caracteristicas de alguns quimicos, que se constituem nas materias-primas utilizadas nos processos de galvanoplastia, relacionando-os aos seus provaveis efeitos toxicos produzidos no organismo humano