AEBP1 Contributes to Breast Cancer Progression by Facilitating Cell Proliferation, Migration, Invasion, and Blocking Apoptosis

Abstract

Background: The aberrant expression of adipocyte enhancer binding protein 1 (AEBP1) has been observed in many cancers and it seems to be involved in the tumorigenesis, progression, and metastasis in numerous tumor types. However, the contribution of AEBP1 in breast cancer (BCa) remains inexplicable.

Methods: Information related to the diagnostic significance and expression of AEBP1 in BCa was obtained from the public dataset Kaplan-Meier Plotter (http://kmplot.com/analysis/) and the dataset UALCAN (https://ualcan.path.uab.edu/index.html). The MTT (methyl thiazolyl tetrazolium) assay, colony formation assay, Transwell® assay, and FACS (fluorescence-activated cell sorting) assay were used to detect the proliferation, invasive and apoptotic ability of cells before and after treatment. In addition, we constructed an AEBP1 overexpression vector and silenced AEBP1, combined with Real-Time Quantitative Reverse Transcription PCR (qRT-PCR), western blot, immunohistochemistry and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling) assay to investigate the prognostic significance, biological functions and potential mechanisms of AEBP1 in BCa.

Results: Higher expression of AEBP1 mRNA (message RNA) was observed in BCa patients with later-stage, who obtained poorer overall survival. Meanwhile, compared with adjacent noncancerous tissues, AEBP1 protein expression was dramatically upregulated in the BCa ones. Furthermore, overexpressed AEBP1 enhanced cell proliferation, migration, invasion, and blocked cell apoptosis in BCa cells. Moreover, the research certificated that AEBP1 upregulated the expression of MMP (matrix metalloproteinase)-2, 9, vimentin, N-cadherin (neural-cadherin), phosphorylation of ERK (extracellular signal-regulated kinase), Smad2/3 (Abbreviated from Sma for nematode and Mad for Drosophila) and AKT (V-akt murine thymoma viral oncogene homolog), while down-regulated the expression of E-cadherin (epithelial cadherin) and PTEN (phosphatase and tensin homolog deleted on chromosome 10). To inhibit cell apoptosis, enforced expression of AEBP1 effectively blocked the cleavage of caspase 9 and p53 (protein 53) and promoted the expression of anti-apoptotic protein Bcl-2 (B-cell lymphoma-2). Finally, AEBP1 accelerated subcutaneously transplanted tumor growth in nude mice by increasing the expression of the cell proliferation biomarker ki67, the phosphorylation of AKT, and blocked apoptosis in vivo.

Conclusions: In summary, these data suggested the important role of AEBP1 in the BCa progression, which could be used as a potential biomarker for prognostic hallmark and a novel therapeutic strategy.

Keywords: adipocyte enhancer binding protein 1 (AEBP1); apoptosis; breast cancer (BCa); cancer progression; epithelial-mesenchymal transition (EMT); signaling pathways.