RESUMO
Resistance of cancer cells to chemotherapeutic agents is one of the main causes of treatment failure. In order to detect proteins potentially involved in the mechanism of resistance to taxanes, we assessed differences in protein expression in MCF-7 breast cancer cells that are sensitive to paclitaxel and in the same cells with acquired resistance to paclitaxel (established in our lab). Proteins were separated using two-dimensional electrophoresis. Changes in their expression were determined and proteins with altered expression were identified using mass spectrometry. Changes in their expression were confirmed using western blot analysis. With these techniques, we found three proteins expressed differently in resistant MCF-7 cells, i.e., thyroid hormone-interacting protein 6 (TRIP6; upregulated to 650%), heat shock protein 27 (HSP27; downregulated to 50%) and cathepsin D (downregulated to 28%). Silencing of TRIP6 expression by specific siRNA leads to decreased number of grown resistant MCF-7 cells. In the present study we have pointed at some new directions in the studies of the mechanism of resistance to paclitaxel in breast cancer cells.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Paclitaxel/farmacologia , Proteoma/metabolismo , ATPases Associadas a Diversas Atividades Celulares , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias da Mama , Catepsina D/metabolismo , Resistencia a Medicamentos Antineoplásicos , Feminino , Proteínas de Choque Térmico HSP27/metabolismo , Proteínas de Choque Térmico , Humanos , Proteínas com Domínio LIM/metabolismo , Células MCF-7 , Chaperonas Moleculares , Complexo de Endopeptidases do Proteassoma , Fatores de Transcrição/metabolismoRESUMO
The resistance of cancer cells to chemotherapeutic drugs represents a major problem in cancer treatment. Despite all efforts, mechanisms of resistance have not yet been elucidated. To reveal proteins that could be involved in resistance to taxanes, we compared protein expression in whole cell lysates of SK-BR-3 breast cancer cells sensitive to paclitaxel and in lysates of the same line with acquired resistance to paclitaxel. The resistant SK-BR-3 cell line was established in our lab. Protein separation was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectro-metry. With these techniques we identified four proteins with different expression in resistant SK-BR-3 cells, i.e., serpin B3, serpin B4, heat shock protein 27 (all three upregulated) and cytokeratin 18 (downregulated). Observed changes were confirmed using western blot analysis. This study suggests new directions worthy of further study in the effort to reveal the mechanism of resistance to paclitaxel in breast cancer cells.
