RESUMO
The signalling adaptor p62 is frequently overexpressed in numerous cancer types. Here, we found that p62 expression was elevated in metastatic breast cancer and its overexpression correlated with reduced metastasis- and relapse-free survival times. Analysis of p62 expression in breast cancer cell lines demonstrated that high p62 expression was associated with the invasive phenotypes of breast cancer. Indeed, silencing p62 expression attenuated the invasive phenotypes of highly metastatic cells, whereas overexpressing p62 promoted the invasion of non-metastatic cells in in vitro microfluidic model. Moreover, MDA-MB-231 cells with p62 depletion which were grown in a three-dimensional culture system exhibited a loss of invasive protrusions. Consistently, genetic ablation of p62 suppressed breast cancer metastasis in both zebrafish embryo and immunodeficient mouse models, as well as decreased tumourigenicity in vivo. To explore the molecular mechanism by which p62 promotes breast cancer invasion, we performed a co-immunoprecipitation-mass spectrometry analysis and revealed that p62 interacted with vimentin, which mediated the function of p62 in promoting breast cancer invasion. Vimentin protein expression was downregulated upon p62 suppression and upregulated with p62 overexpression in breast cancer cells. Linear regression analysis of clinical breast cancer specimens showed a positive correlation between p62 and vimentin protein expression. Together, our findings provide strong evidence that p62 functions as a tumour metastasis promoter by binding vimentin and promoting its expression. This finding might help to develop novel molecular therapeutic strategies for breast cancer metastasis treatment.
Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Metástase Neoplásica/patologia , Proteína Sequestossoma-1/genética , Vimentina/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Regulação para Baixo/fisiologia , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Células HEK293 , Humanos , Células MCF-7 , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica/patologia , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/patologia , Regulação para Cima/fisiologia , Peixe-ZebraRESUMO
A method for determination of 16 kinds of polycyclic aromatic hydrocarbons ( PAHs ) in atmospheric fine particles ( PM2. 5) was developed based on accelerated solvent extraction-direct injection coupled with high performance liquid chromatography (HPLC). PM2. 5 was collected by glass fiber membrane filter and pretreated with acetonitrile by accelerated solvent extraction. The extract was separated by ZORBAX Eclipse PAH column with acetonitrile and water as mobile phase, and detected by ultraviolet and fluorescence detectors. The result showed that the 16 kinds of PAHs were well separated and there were good linear relationships ( r≥0. 9998) in the concentration range of 0. 025 -5. 00 μg / mL. The recoveries were from 78. 3% to 113. 2% . The relative standard deviations ranged from 0. 5% to 9. 5% . The detection limits were 0. 007 - 0. 062 ng / m3 . The method was simple, rapid, accurate and sensitive, and suitable for the simultaneous determination of 16 kinds of PAHS in PM2. 5.