Annexin A12-26 hydrogel improves healing properties in an experimental skin lesion after induction of type 1 diabetes.

Diabetes mellitus (DM) is characterized by metabolic alterations that involve defects in the secretion and/or action of insulin, being responsible for several complications, such as impaired healing. Studies from our research group have shown that annexin A1 protein (AnxA1) is involved in the regulation of inflammation and cell proliferation. In light of these findings, we have developed a new technology and evaluated its effect on a wound healing in vivo model using type 1 diabetes (T1DM)-induced mice. We formulated a hydrogel containing AnxA12-26 using defined parameters such as organoleptic characteristics, pH, UV-vis spectroscopy and cytotoxicity assay. UV-vis spectroscopy confirmed the presence of the associated AnxA12-26 peptide in the three-dimensional hydrogel matrix, while the in vitro cytotoxicity assay showed excellent biocompatibility. Mice showed increased blood glucose levels, confirming the efficacy of streptozotocin (STZ) to induce T1DM. Treatment with AnxA12-26 hydrogel showed to improve diabetic wound healing, defined as complete re-epithelialization and tissue remodeling, with reduction of inflammatory infiltrate in diabetic animals. We envisage that the AnxA12-26 hydrogel, with its innovative composition and formulation be efficient on improving diabetic healing and contributing on the expansion of the therapeutic arsenal to treat diabetic wounds, at a viable cost.

Biological and physical approaches on the role of piplartine (piperlongumine) in cancer.

Chronic inflammation provides a favorable microenvironment for tumorigenesis, which opens opportunities for targeting cancer development and progression. Piplartine (PL) is a biologically active alkaloid from long peppers that exhibits anti-inflammatory and antitumor activity. In the present study, we investigated the physical and chemical interactions of PL with anti-inflammatory compounds and their effects on cell proliferation and migration and on the gene expression of inflammatory mediators. Molecular docking data and physicochemical analysis suggested that PL shows potential interactions with a peptide of annexin A1 (ANXA1), an endogenous anti-inflammatory mediator with therapeutic potential in cancer. Treatment of neoplastic cells with PL alone or with annexin A1 mimic peptide reduced cell proliferation and viability and modulated the expression of MCP-1 chemokine, IL-8 cytokine and genes involved in inflammatory processes. The results also suggested an inhibitory effect of PL on tubulin expression. In addition, PL apparently had no influence on cell migration and invasion at the concentration tested. Considering the role of inflammation in the context of promoting tumor initiation, the present study shows the potential of piplartine as a therapeutic immunomodulator for cancer prevention and progression.

Melatonin Differentially Modulates NF-кB Expression in Breast and Liver Cancer Cells.

BACKGROUND: NF-kB (nuclear factor kappa B) is a transcription factor composed of two subunits, p50 and p65, which plays a key role in the inflammatory process. Melatonin has oncostatic, antiangiogenic and antimetastatic properties, and some recent studies have indicated an inhibitory effect of melatonin on NF-kB in some types of cancer. This work aims to investigate the effects of melatonin treatment on the expression of NFkB in breast and liver cancer models. METHOD: The breast cancer xenographic model was performed using female Balb/c nude athymic mice injected with MDA-MB-231 cells. The animals were treated with 40 mg/Kg of melatonin for 21 days. Volume of the tumors was measured with a digital caliper. Hepatocarcinoma model was developed by using the HepG2 cells in vitro, treated with 1 mM melatonin for 24 h. The expression of NF-kB protein was verified by immunohistochemistry and immunocytochemistry and quantified by optical densitometry, in vivo study and in vitro study, respectively. NF-kB gene expression was performed by quantitative RT-PCR. RESULTS: The breast cancer xenografts nude mice treated with melatonin showed reduced tumor size (P=0.0022). There was a decrease in NF-kB protein staining (P=0.0027) and gene expression (P=0.0185) in mice treated with melatonin. The opposite results were observed for the hepatocarcinoma model. HepG2 cells treated with melatonin showed an increase in the NF-kB immunostaining when compared to control cells (P=0.0042). CONCLUSION: Our results indicated that the treatment with melatonin was able to decrease both gene and protein expressions of NF-kB in breast cancer cells and, conversely, increase the transcription factor protein expression in hepatocarcinoma cells. These data highlighted a double role in the expression of NF-kB, depending on the cell type. Further studies are needed to better elucidate the action of melatonin in NF-kB, since this transcription factor acts on different signaling pathways that are fundamental for carcinogenesis.

Expression profiles of Annexin A1, formylated peptide receptors and cyclooxigenase-2 in gastroesophageal inflammations and neoplasias.

The anti-inflammatory protein Annexin-A1 (ANXA1) is associated to tumor invasion process and its actions can be mediated by formylated peptides receptors (FPRs). Therefore, we evaluated the expression and correlation of ANXA1, FPR and cyclooxygenase-2 (COX-2) enzyme in esophageal and stomach inflammations and neoplasias. The study of proteins was performed by immunohistochemistry in biopsies of esophagitis, Barrett's esophagus, squamous cell carcinoma and adenocarcinoma of the esophagus, as well as gastritis, stomach polypus and gastric adenocarcinoma. The intensity of the expressions was evaluated by densitometry. The immunohistochemical and densitometric analyzes showed specificity for the FPR1 receptor and modulation of the ANXA1, COX-2 and FPR1 expressions in the epithelial cells in the different studied conditions. Increased immunoreactivity of these proteins was observed in cases of inflammation and stomach polypus. Interestingly, moderate immunoreactivity for ANXA1 and FPR1 but increased immunolabeling for COX-2 were observed in Barrett́s esophagus and esophageal adenocarcinomas. Also, there was reduced expression of ANXA1 and FPR1 in esophageal carcinoma but COX-2 overexpression in this tumor. There was no expression of FPR2 but ANXA1 and FPR1 expressions were positively correlated in all clinical conditions studied. Positive correlation between ANXA1 and COX-2 were also observed in inflammation conditions while negative correlation between ANXA1 and COX-2 was observed in esophageal carcinoma. Our results demonstrate the unregulated expression of ANXA1 and COX-2 in precursor lesions of esophageal and stomach cancers, reinforcing their involvement in gastroesophageal carcinogenesis. In addition, the data show that the actions of ANXA1 in the inflammatory and neoplastic processes of the esophagus and stomach are specifically mediated by the FPR1 receptor.

Anti-inflammatory mechanisms of the annexin A1 protein and its mimetic peptide Ac2-26 in models of ocular inflammation in vivo and in vitro.

Annexin A1 (AnxA1) is a protein that displays potent anti-inflammatory properties, but its expression in eye tissue and its role in ocular inflammatory diseases have not been well studied. We investigated the mechanism of action and potential uses of AnxA1 and its mimetic peptide (Ac2-26) in the endotoxin-induced uveitis (EIU) rodent model and in human ARPE-19 cells activated by LPS. In rats, analysis of untreated EIU after 24 and 48 h or EIU treated with topical applications or with a single s.c. injection of Ac2-26 revealed the anti-inflammatory actions of Ac2-26 on leukocyte infiltration and on the release of inflammatory mediators; the systemic administration of Boc2, a formylated peptide receptor (fpr) antagonist, abrogated the peptide's protective effects. Moreover, AnxA1(-/-) mice exhibited exacerbated EIU compared with wild-type animals. Immunohistochemical studies of ocular tissue showed a specific AnxA1 posttranslational modification in EIU and indicated that the fpr2 receptor mediated the anti-inflammatory actions of AnxA1. In vitro studies confirmed the roles of AnxA1 and fpr2 and the protective effects of Ac2-26 on the release of chemical mediators in ARPE-19 cells. Molecular analysis of NF-κB translocation and IL-6, IL-8, and cyclooxygenase-2 gene expression indicated that the protective effects of AnxA1 occur independently of the NF-κB signaling pathway and possibly in a posttranscriptional manner. Together, our data highlight the role of AnxA1 in ocular inflammation, especially uveitis, and suggest the use of AnxA1 or its mimetic peptide Ac2-26 as a therapeutic approach.