Juliana de Oliveira Silva

Doxorubicin-loaded nanocarriers: A comparative study of liposome and nanostructured lipid carrier as alternatives for cancer therapy

Nowadays cancer is one of the most common causes of deaths worldwide. Conventional antitumor agents still present various problems related to specificity for tumor cells often leading to therapeutic failure. Nanoscale particles are considered potential alternative to direct access of drugs into tumor cells, therefore increasing the drug accumulation and performance. The aim of this study was to evaluate the antitumor activity of doxorubicin (DOX)-loaded nanostructured lipid carriers (NLC) versus liposomes against a breast cancer animal experimental model. NLC-DOX and liposomes-DOX were successfully prepared and characterized. Tumor-bearing mice were divided into five groups (blank-NLC, blank-liposome, DOX, NLC-DOX, liposome-DOX). Each animal received by the tail vein four doses of antitumoral drugs (total dose, 16mg/kg), every 3 days. Antitumor efficacy was assessed by measuring 1) tumor volume, calculating the inhibitory ratio (TV-IR, see after) and 2) acquiring scintigraphic images of the tumor using doxorubicin radiolabeled with technetium-99m as an imaging tumor probe. Liposome-DOX and free DOX did not showed differences in the tumor mean volume, whereas NLC-DOX proved to be the best treatments in controlling the tumor growth. NLC-DOX showed an inhibition ration (TV-IR) of 73.5% while free DOX and liposome-DOX decreased TV-RI of 48.8% and 68.0%, respectively. Tumor was clearly visualized in controls, DOX, and liposome-DOX groups. Yet, regarding the NLC-DOX group, tumor was barely identified by the image, indicating antitumor efficacy. Moreover, both NLC and liposomes proved to be able to delay the occurrence of lung metastasis. In conclusion, results of this study indicated that NLC-DOX might be an alternative strategy to achieve an efficient antitumor activity.

Prognostic significance of tissue and serum HER2 and MUC1 in canine mammary cancer

The aim of our study was to compare serum levels and protein tissue of human epidermal growth factor receptor–2 proto-oncogene (HER2) and mucin 1 (MUC1) using an antigen-capture enzyme-linked immunosorbent assay and immunohistochemistry (IHC) in canine mammary carcinomas and investigate how the 2 markers correlate with dogs with metastasis and without metastasis to a regional lymph node. Forty-eight female dogs were selected, including 14 with non-metastatic cancer, 14 with lymph node metastasis, and 20 healthy animals. Serum samples were collected from all the animals and tissues from 28 dogs with malignant mammary tumor with or without metastasis for evaluated HER2 and MUC1 expression. Tissue sample were evaluated for MUC1 and HER2 immunoexpression by IHC. The results showed measurable serum levels of MUC1 and HER2 in all groups. While serum MUC1 levels were significantly higher in animals with metastasis than the other 2 groups, no increase was observed in HER2 serum levels. The MUC1 IHC results showed that only membrane immunostaining was significantly different between the groups. Statistically, there was an association between immunostaining and the serum HER2 levels. Our results indicate that serum concentrations of HER2 and the IHC staining pattern for HER2 in primary tumor do not correlate with the presence of regional metastasis. However, increased concentrations of MUC1 in the serum of dogs with mammary cancer are associated with the presence of metastasis to regional lymph nodes. A membrane pattern of IHC staining for MUC1 in the primary tumor suggests that metastases to regional lymph node are present.

Toxicological study of a new doxorubicin-loaded pH-sensitive liposome: A preclinical approach

&NA; 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. HighlightsDOX‐encapsulated liposomes prevent renal toxicity in miceFree DOX leading to more extensive hepatic injury than SpHL‐DOXElectrocardiographic parameters were much less affected by SpHL‐DOX than other groupsSpHL prove to be a promising strategy to overcome limitations of clinical use of DOX

α- Tocopherol succinate loaded nano-structed lipid carriers improves antitumor activity of doxorubicin in breast cancer models in vivo

Combination-based chemotherapies have been the standard treatment for multiple solid tumors since the 1960s. Combined therapies where both agents have toxicity results in dose-limiting effects. α- tocopherol succinate (TS) is an analogue of vitamin E that exhibits antitumor properties in the absence of toxicity. Hence, its combination with a frontline chemotherapy, doxorubicin (DOX) is an alternative to increase antitumor efficacy. Therefore, the aim of this work was to evaluate the antitumor activity of nanostructed lipid carriers (NLC) loaded with TS and DOX. The NLC-TS-DOX were prepared, characterized and radiolabeled with technetium-99m. Cytotoxicity studies were performed in vitro, using two breast cancer cell lines, MDA-MB-231 and 4T1. Biodistribution and antitumor activity were evaluated in 4T1 tumor-bearing mice. The results showed that NLC-TS-DOX had a small diameter (85 nm) and a long blood clearance (T1/2β = 1107.71 min) that consequently resulted in a higher tumor uptake compared to contralateral muscle for up to 48 h. Drug combination studies in MDA-MB-231 and 4T1 cells showed a combination index below 0.8 at ED50-90 for both cell lines. Interestingly, a high synergism was found at ED90. Antitumor activity showed a better control of tumor growth for animals treated with NLC-ST-DOX. The small particle size, along with the EPR effect and the controlled release of DOX from the particle, associated with the synergic combination between TS and DOX led to an increase of the antitumor efficacy. Therefore, NLC-TS-DOX can be considered a plausible alternative to improve antitumor efficacy in DOX therapeutic regimens.

Nanoparticle mucoadhesive system as a new tool for fish immune system modulation

Recently, chitosan-based nanoparticles with mucoadhesive properties emerged as a strategy for mucosal drug release. This study aimed to characterize the interaction of mucoadhesive system chitosancoated PLGA nanoparticles (NPMA) with fish external mucus. NP suspensions with fluorescent probe were prepared and characterized by size, polydispersity, zeta potential and pH measures. In post-exposure fish were observed an increase in fluorescence imaging over time and it was significantly influenced by NPMA concentration. We also observed the main predominance the fluorescence in the spleen, followed by liver, gill and other tissues. The use of mucoadhesive nanocarriers becomes an alternative for administration of drugs and immunomodulators in immersion systems since the nanosystem can adhere to the mucosal surface of the fish with little residual effect in the water.

Synthesis of cholesterol-based neoglycoconjugates and their use in the preparation of liposomes for active liver targeting

Carbohydrate receptors on liver represent attractive targets for receptor-mediated delivery of nanostructured therapeutics. In this study, two new cholesterol-based glycoconjugates derived from d-galactose and N-acetylglucosamine were synthesized and incorporated into liposomes. 99mTc-Cholesterol-DTPA complex was used for radiolabeling experiments in vivo with high radiochemical yields and stability. Biodistribution studies confirmed the targeting of galactosylated liposomes (GalL) to liver cells. These results indicated that GalL could be considered a promising drug delivery system for liver diseases therapy.