Melka Coêlho Sá

Antibacterial, antibiofilm and cytotoxic activities of Terminalia fagifolia Mart. extract and fractions

BackgroundThe methicillin resistance of bacteria from the genus Staphylococcus and its ability to form biofilms are important factors in pathogenesis of these microorganisms. Thus, the search for new antimicrobials agents, especially from plants, has been intensified. In this context, Terminalia species have been the subject of research for many pharmacological activities. In this study we evaluated the antibacterial, antibiofilm and cytotoxic activities of the ethanol extract (EtE) from Terminalia fagifolia stem bark as well as that of three fractions of the extract (AqF, HaF and WSF).MethodsWe determined the minimum inhibitory concentration (MIC) by microdilution in 96-well plates, where the strains were exposed to serial dilutions of the ethanol extract and fractions, ranging from 12.5 to 400 μg/mL. We then determined the minimum bactericidal concentration (MBC), seeding the inoculum (10 μL) with concentrations equal to or greater than the MIC in Mueller-Hinton agar. To test the antibiofilm activity biofilm formation was induced in the presence of concentrations equivalent to 1/2, 1/4 and 1/8 of the MIC extract or fraction tested. In addition, the effect of the EtE and the fractions on cell viability was tested by the MTT assay on human MCF-7 breast cancer and mouse fibroblast NIH/3T3. To obtain high-resolution images of the effect of the aqueous fraction on the bacterial morphology, atomic force microscopy (AFM) imaging of treated S. aureus cells was performed.ResultsWe observed antibacterial activity of EtE and fractions with MICs ranging from 25–200 μg/mL and MBCs ranging from 200–400 μg/mL. Regarding antibiofilm activity, both the EtE as the AqF, HaF and WSF fractions showed significant inhibition of the biofilm formation, with inhibition of biofilms formation of over 80% for some strains. The EtE and fractions showed a moderate cytotoxicity in cell line NIH/3T3 viability and potential antitumoral activity on human breast cancer cell line MCF-7. The microscopic images obtained revealed morphological changes to the S. aureus ATCC 29213 surface caused by AqF, as well as significant size alterations.ConclusionsThe results show potential antibacterial, antibiofilm and antitumoral activities of the ethanol extract and fractions of T. fagifolia.

DNA base excision repair proteins APE-1 and XRCC-1 are overexpressed in oral tongue squamous cell carcinoma

BACKGROUND DNA repair systems play a critical role in protecting the human genome from damage caused by carcinogens. Modifications in DNA repair genes may be responsible for tumor development and resistance of malignant cells to chemotherapeutic agents. The major pathway for oxidative DNA damage repair is the base excision repair pathway. This study aimed to assess the immunoexpression of DNA repair proteins APE-1 and XRCC-1 and its association with clinical, histologic, and survival parameters in oral tongue squamous cell carcinoma, to investigate a possible role for those proteins in tumor behavior. METHODS The expression of APE-1 and XRCC-1 was evaluated by immunohistochemistry in 82 cases of oral tongue squamous cell carcinoma. Histopathological grading was performed for each case. Pearsons chi-square and Fishers exact tests were used to determine the association between protein expressions and clinicopathological features of tumors, whereas Kaplan-Meier curves and Cox regression were used to analyze disease-specific and disease-free survival. Statistical significance was set at P ≤ 0.05. RESULTS APE-1 was highly expressed in the nucleus and cytoplasm in 64.6% of cases, and XRCC-1 showed overexpression only in the nucleus in 61% of cases. High expression of XRCC-1 was significantly associated with tumors at early clinical stages (I and II, P < 0.01) and nodal status (P = 0.03). Both proteins were not associated with other clinical parameters, histopathological grading, or survival. CONCLUSIONS DNA base excision repair proteins APE-1 and XRCC-1 are upregulated in oral tongue squamous cell carcinoma, and XRCC-1 expression is associated with better clinical staging and nodal status.

Immunohistochemical study of macrophages subpopulations associated with squamous cell carcinoma of the tongue, with and without metastasis

Introducao: As celulas do estroma interagem com as celulas neoplasicas e desempenham papel importante na invasao e na metastase do câncer. Os macrofagos associados ao tumor (TAMs) podem se apresentar com fenotipo M1, importantes celulas efetoras, ou fenotipo M2, capazes de suprimir a funcao dos macrofagos M1 e influenciar na angiogenese e no reparo tecidual. O anticorpo CD68 reconhece os macrofagos M1 e M2, enquanto o anticorpo CD163 e especifico para a identificacao apenas de macrofagos M2. Objetivo: Investigar a presenca dos TAMs em uma serie de casos de carcinoma epidermoide (CE) de lingua, associando-a a ocorrencia de metastase. Material e metodos: A tecnica imuno-histoquimica foi utilizada para avaliar a imunopositividade ao CD68 e CD163 em 27 casos de CE de lingua. Resultados: A porcentagem de macrofagos CD68 positivos foi maior do que a de macrofagos CD163 positivos em todos os especimes estudados. Comparando a imunomarcacao de CD68 e CD163 nos grupos estudados, verificou-se que nos casos sem metastase havia maior proporcao de celulas CD68 positivas em relacao as CD163 positivas, o que foi estatisticamente significativo. Conclusao: Diante desses resultados, observou-se a predominância de macrofagos M1 em casos de CE de lingua sem metastase, sugerindo a influencia dessas celulas no comportamento clinico da lesao.