Myeloid-derived suppressor cells and associated events in urethane-induced lung cancer

OBJECTIVES: Myeloid-derived suppressor cells contribute to the immunosuppressive microenvironment during tumor development and limit the efficacy of cancer immunotherapy. Identifying myeloid-derived suppressor cells and associated factors is the first step in creating strategies to reverse the suppressive effects of these cells on the immune system. METHODS: To induce lung cancer, we administered 2 doses of urethane to BALB/c mice and observed these animals for 120 days. After this period, we evaluated the percentage of myeloid-derived suppressor cells in the blood, lung and bone marrow. The expression of alpha-smooth muscle actin, transforming growth factor-β, Toll-like receptor 2, Toll-like receptor 4, and interleukin-6 was also determined in the lung tissue. RESULTS: Myeloid-derived suppressor cells were increased in all evaluated tissues after lung cancer development in association with increased Toll-like receptor 4 expression and decreased interleukin-6 expression in the lung. We observed alpha-smooth muscle actin and transforming growth factor-β expression in lung nodules. CONCLUSIONS: We believe that the early diagnosis of cancer through determining the blood levels of myeloid-derived suppressor cells followed by the depletion of these cells should be further investigated as a possible approach for cancer treatment. .

Perda de amostras em tissue microarray: comparação entre técnicas com uso de fita adesiva comercial, lâminas silanizadas pelo método tradicional ou por método modificado / Loss of tissue samples in the tissue microarray: comparison between techniques using commercial adhesive tape, silane-coated microslides by the conventional method and by a modified technique

Introdução/objetivo: O microarranjo tecidual, ou tissue microarray (TMA), permite avaliar múltiplas amostrasde tecido em um único bloco. Um dos problemas do TMA é o descolamento dos cortes teciduais, por isso, para reduzir essa perda, tem-se utilizado fita adesiva especial comercial. Não há relatos comparando o uso dessas fitas adesivas com a técnica de silanização modificada. O objetivo desse estudo foi comparar as perdas de cortes entre lâminas usando fitas adesivas comerciais, lâminas silanizadas por técnica convencional elâminas silanizadas por técnica modificada, com menor consumo de acetona. Material e método: O TMA foiconstruído com blocos de tecido hepático, em dispositivo de base fixa, colocando-se 32 cilindros de 2 mmde diâmetro em duplicata e espaçamento de 2,2 mm. Quinze secções de 4 μm foram colocadas em lâminas silanizadas a 4% por técnica convencional (grupo 1), 15 em lâminas silanizadas com técnica modificada (6%de silano e com uso mínimo de acetona) (grupo 2) e 15 em lâminas com fita adesiva comercial de acordo comas recomendações do fabricante (grupo 3). Todas as lâminas foram processadas por imuno-histoquímica para citoqueratina 18, com recuperação antigênica em tampão citrato pH 6, em microondas. As perdas de amostrasforam quantificadas e expressas como: perda total (≥ 80%), quase total (75% a 79%) ou parcial (50% a 74%).Resultados: A perda de tecidos foi semelhante nos três grupos: com silanização tradicional, modificada oufita adesiva comercial (4,9 vs. 3,1 vs. 8,1, respectivamente) (análise de variância [ANOVA], p = 0,3654). Umadas lâminas com a fita adesiva apresentou descolamento artefatual de todos os tecidos e outra de 20 tecidosem um dos lados. Nenhuma das lâminas silanizadas apresentou tal artefato. Conclusão: Lâminas silanizadas têm resultados satisfatórios, requerem menos treinamento técnico e reduzem os custos da utilização do TMA justificando seu uso em pesquisa...

Introduction/objective: The tissue microarray (TMA) technique allows the evaluation of multiple tissue samplesin a single block. One of the problems of TMA is the ungluing of tissue sections, thus commercial adhesive tape has been used to reduce this loss. There are no reports comparing the use of the commercial adhesive tape with the use of the modified silane-coated technique. The objective of this study was to compare section loss in slides using commercial adhesive tape, silane-coated microslides with the conventional technique or with the modified technique. Material and method: The TMA was constructed with hepatic tissue blocks embedded in paraffin, using a fixed base device, placing 32 cylinders of 2 mm in diameter in duplicate and 2.2 mm apart from each other. Fifteen 4-μm sections were placed on conventional silane-coated microslides at 4% (Group 1), 15 on silane-coated microslides with a modified technique (6% of silane and minimum use of acetone) (Group 2), and 15 on slides using commercial adhesive tape, according to the manufacturer's recommendations (Group 3). All microslides were processed by immunohistochemistry for cytokeratin 18, with antigen retrieval accomplished by incubation with citrate buffer pH 6.0 with microwave enhancement. Samples loss was quantified and expressed as: total (≥ 80%), almost complete (75% to 79%) or partial (50% to 74%). Results: The loss of sections was similar in all three groups (4.9 vs. 3.1 vs. 8.1, respectively) (analysis of variance [ANOVA], p = 0.3654). One slide usingcommercial adhesive tape showed artifactual ungluing of all sections and another one showed loss of 20 sampleson one side of the slide. None of the silane-coated microslides showed such artifact. Conclusions: Silane-coated microslides show adequate results, require less technical training and reduce the cost of TMA procedure, whatjustifies their use in research...