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Abstract(s)
Introdução: A sobreexpressão de HER2 está presente em cerca de 20% dos cancros da mama, dos quais apenas 15-26% apresentam uma resposta inicial à monoterapia com Trastuzumab e, praticamente todos acabam por progredir. Encontrar fatores que contribuam para a agressividade e modulem o tratamento de tumores HER2 positivos é, por isso, de forte interesse clínico. Estudos em mulheres com cancro da mama demonstraram uma correlação positiva entre LDL sérico e tamanho e agressividade tumoral, sendo os tumores mais comummente HER2+ se o LDL for elevado. Estudos in vitro demostraram que exposição a LDL aumenta significativamente a ativação das vias do Akt, ERK e JNK, todas na dependência do HER2. Estes estudos levaram-nos a colocar a hipótese de que a exposição a LDL possa induzir um aumento de expressão e disponibilidade membranar do HER2, o que poderá conduzir a maior agressividade tumoral e modular a sensibilidade ao Trastuzumab. Por isso, neste trabalho investigamos o efeito da exposição a níveis elevados de LDL na expressão de HER2 em linhas celulares de cancro da mama, na agressividade de linhas de cancro da mama HER2 positivas e na sensibilidade terapêutica ao Trastuzumab.
Métodos: Utilizámos duas linhas celulares humanas de cancro da mama: BT474 (ER+, PR+, HER2+) e T47D (ER+, PR+, HER2-). A expressão e localização membranar do HER2 foi avaliada por Western Blot e imunofluorescência, respetivamente. A proliferação celular foi avaliada por contagem de células no hemocitómetro e pelo ensaio colorimétrico de Sulforrodamina B. A transmigração endotelial foi avaliada por microscopia time lapse. A sensibilidade ao Trastuzumab foi avaliada por ensaio colorimétrico de Sulforrodamina B.
Resultados: A exposição a LDL induziu um aumento da expressão membranar de HER2 e aumentou a sensibilidade tumoral ao Trastuzumab.
Background: The overexpression of HER2 is present in about 20% of breast cancers, in which only 15-26% display an initial response to the monotherapy with Trastuzumab and almost all end up progressing. Finding factors that might contribute to its aggressivity and that can modulate the treatment of tumors HER2 positive is, therefore, of keen clinical interest. Studies in women with breast cancer have shown a positive correlation between serum LDL and the tumor’s size and aggressivity, being most commonly HER2+ if the LDL is elevated. In vitro studies show that the exposition to LDL significantly increase the activation of the Akt, ERK and JNK pathways, all in the dependence of HER2. These studies lead us to the hypothesis that the exposition to LDL may lead to an increase in the expression and membrane availability of HER2, which may lead to a higher tumor aggressiveness and modulate the tumor’s sensitivity to Trastuzumab. Therefore, in this work we investigate the effect of the exposure to high levels of LDL on the expression of HER2 in breast cancer cell lines, on the aggressiveness in the HER2 positive breast cancer cell lines and in the therapeutic sensitivity to Trastuzumab. Methods: We used two human breast cancers cell lines: BT474 (ER+, PR+, HER2+) and T47D (ER+, PR+, HER2+). The expression and membrane localization of the HER2 was evaluated by Western Blot and immunofluorescence, respectively. The cellular proliferation was evaluated by counting the cells in the hemacytometer and by the Sulforhodamine B assay. The endothelial transmigration was evaluated by time lapse microscopy. The sensitivity to Trastuzumab was evaluated by the Sulforhodamine B assay. Results: The exposition to LDL-cholesterol increased the membrane HER2 and increased the tumor sensitivity to Trastuzumab.
Background: The overexpression of HER2 is present in about 20% of breast cancers, in which only 15-26% display an initial response to the monotherapy with Trastuzumab and almost all end up progressing. Finding factors that might contribute to its aggressivity and that can modulate the treatment of tumors HER2 positive is, therefore, of keen clinical interest. Studies in women with breast cancer have shown a positive correlation between serum LDL and the tumor’s size and aggressivity, being most commonly HER2+ if the LDL is elevated. In vitro studies show that the exposition to LDL significantly increase the activation of the Akt, ERK and JNK pathways, all in the dependence of HER2. These studies lead us to the hypothesis that the exposition to LDL may lead to an increase in the expression and membrane availability of HER2, which may lead to a higher tumor aggressiveness and modulate the tumor’s sensitivity to Trastuzumab. Therefore, in this work we investigate the effect of the exposure to high levels of LDL on the expression of HER2 in breast cancer cell lines, on the aggressiveness in the HER2 positive breast cancer cell lines and in the therapeutic sensitivity to Trastuzumab. Methods: We used two human breast cancers cell lines: BT474 (ER+, PR+, HER2+) and T47D (ER+, PR+, HER2+). The expression and membrane localization of the HER2 was evaluated by Western Blot and immunofluorescence, respectively. The cellular proliferation was evaluated by counting the cells in the hemacytometer and by the Sulforhodamine B assay. The endothelial transmigration was evaluated by time lapse microscopy. The sensitivity to Trastuzumab was evaluated by the Sulforhodamine B assay. Results: The exposition to LDL-cholesterol increased the membrane HER2 and increased the tumor sensitivity to Trastuzumab.
Description
Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2021
Keywords
Cancro da mama HER2-positivo LDL-colesterol Trastuzumab