Biochemically, Alzheimeŕs disease (AD) is characterized by the presence of abnormal deposition of beta amyloid peptide (Aβ), which is generated by proteolytic processing from its precursor, the amyloid precursor protein (APP) in a non-physiological pathway. The presence of Aβ in the brain is strongly correlated with cognitive impairment, cholinergic deficiency, bioenergetics disruption, cell death and DNA damage. Galanthamine is an acetylcholinesterase inhibitor (AChEI) used to symptomatic treatment of Alzheimeŕs disease (AD). Several studies have showed that galanthamine has antioxidant properties, anti-apoptotic action and also promotes neurogenesis; however, it is unknown whether galanthamine may present protection mechanisms against Aβinduced genomic instability. To understand the mechanisms of this neuroprotection, we studied the effects of galanthamine on the cell toxicity and DNA strand breaks induced by Aβ using a set of biomarkers such as clonogenic assay, cytokinesis block micronucleus cytome (CBNM-cyt) and comet assay. The results showed that galanthamine treatments were capable to significantly reduce the Aβ-induced cytotoxicity and genotoxicity. In conclusion, this study demonstrated that in addition to inhibition of acetylcholinesterase (AChE), galanthamine exerts antigenotoxic properties. This relevant property of galanthamine is worthwhile exploring further which may improve the development of new diseases-modifying agents.

Our results confirm the action of melatonin on the miR-152-3p regulation known to be involved in the progression of breast cancer.

Background: The high mortality rate of breast cancer is related to the occurrence of metastasis, a process that is promoted by tumor angiogenesis. MicroRNAs are small molecules of noncoding mRNA that play a key role in gene regulation and are directly involved in the progression and angiogenesis of various tumor types, including breast cancer. Several miRNAs have been described as promoters or suppressors angiogenesis and may be associated with tumor growth and metastasis. Melatonin is an oncostatic agent with a capacity of modifying the expression of innumerable genes and miRNAs related to cancer. Objective: The aim of this study was to evaluate the role of melatonin and the tumor suppressor miR- 148a-3p on angiogenesis of breast cancer. Method: MDA-MB-231 cells were treated with melatonin and modified with the overexpression of miR-148a-3p. The relative quantification in real-time of miR-148a-3p, IGF-IR and VEGF was performed by real-time PCR. The protein expression of these targets was performed by immunocytochemistry and immunohistochemistry. Survival, migration and invasion rates of tumor cells were evaluated. Finally, the xenograft model of breast cancer was performed to confirm the role of melatonin in the tumor. Results: The melatonin was able to increase the gene level of miR-148a-3p and decreased the gene and protein expression of IGF-1R and VEGF, both in vitro and in vivo. In addition, it also had an inhibitory effect on the survival, migration and invasion of breast tumor cells. Conclusion: Our results confirm the role of melatonin in the regulation of miR-148a-3p and decrease of angiogenic factors.

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The co-expression of androgen (AR) and estrogen (ER) receptors, in terms of higher AR/ER ratio, has been recently associated with poor outcome in ER-positive (ER+) breast cancer (BC) patients. The aim of this study was to analyze if the biological aggressiveness, underlined in ER+ BC tumors with higher AR/ER ratio, could be due to higher expression of genes related to cell proliferation. On a cohort of 47 ER+ BC patients, the AR/ER ratio was assessed by immunohistochemistry and by mRNA analysis. The expression level of five gene proliferation markers was defined through TaqMan®-qPCR assays. Results were validated using 979 BC cases obtained from gene expression public databases. ER+ BC tumors with ratios of AR/ER ≥ 2 have higher expression levels of cellular proliferation genes than tumors with ratios of AR/ER < 2, in both the 47 ER+ BC patients (P < 0.001) and in the validation cohort (P = 0.005). Moreover, BC cases with ratios of AR/ER ≥ 2 of the validation cohort were mainly assigned to luminal B and HER2-enriched molecular subtypes, typically characterized by higher proliferation and poorer prognosis. These data suggest that joint routine evaluation of AR and ER expression may identify a unique subset of tumors, which show higher levels of cellular proliferation and therefore a more aggressive behavior.