title: Effect of the knockdown of death-associated protein 1 expression on cell adhesion, growth and migration in breast cancer cells.
abstract: Death-associated protein 1 (DAP1) is a highly conserved phosphoprotein involved in the regulation of autophagy. A previous clinical study by our group suggested an association between low DAP1 expression and clinicopathological parameters of human breast cancer. In the present study, we aimed to determine the role of DAP1 in cancer cell behaviour in the context of human breast cancer. We developed knockdown sublines of MCF7 and MDA-MB‑231, and performed growth, adhesion and invasion assays and electric cell-substrate impedance sensing (ECIS) studies of the post-wound migration of cells. In addition, we studied the mRNA expression of caspase 8 and 9, DELE, IPS1, cyclin D1 and p21 in the control and knockdown sublines. Knockdown was associated with increased adhesion and migration, significantly so in the MDA-MB-231DAP1kd cell subline (p=0.029 and p=0.001, respectively). Growth in MCF7 cells showed a significant suppression on day 3 (p=0.029), followed by an increase in growth matching the controls on day 5. While no change in the apoptotic response to serum starvation could be attributed to DAP1 knockdown, the expression of known components of the apoptosis pathway (caspase 8) and cell cycle (p21) was significantly reduced in the MCF7DAP1kd cell subline (p≤0.05), while in MDA-MB-231DAP1kd the expression of a pro-apoptotic molecule, IPS1, was suppressed (p≤0.05). DAP1 may have an important role in cell adhesion, migration and growth in the context of breast cancer and has significant associations with the apoptosis pathway. Furthermore, we believe that delayed increase in growth observed in the MCF7DAP1kd cell subline may indicate activation of a strongly pro-oncogenic pathway downstream of DAP1.
authors.affiliation: The London Breast Institute, Princess Grace Hospital, London, UK.
authors.forename: Umar
authors.initials: U
authors.lastname: Wazir
authors.affiliation: Cardiff University-Peking University Cancer Institute (CUPUCI), Cardiff University School of Medicine, Cardiff University, Cardiff, Wales, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sanders
authors.affiliation: Aga Khan University Medical School, Karachi, Pakistan.
authors.forename: Ali
authors.initials: A
authors.lastname: Wazir
authors.affiliation: Pir Mehr Ali Shah Arid Agricultural University, Rawalpindi, Pakistan.
authors.forename: Ruqia Mehmood
authors.initials: RM
authors.lastname: Baig
authors.affiliation: Cardiff University-Peking University Cancer Institute (CUPUCI), Cardiff University School of Medicine, Cardiff University, Cardiff, Wales, UK.
authors.forename: Wen G
authors.initials: WG
authors.lastname: Jiang
authors.affiliation: Department of Breast Surgery, St. George's Hospital and Medical School, University of London, London, UK.
authors.forename: Irina C
authors.initials: IC
authors.lastname: Ster
authors.affiliation: Department of Breast Surgery, St. George's Hospital and Medical School, University of London, London, UK.
authors.forename: Anup K
authors.initials: AK
authors.lastname: Sharma
authors.affiliation: The London Breast Institute, Princess Grace Hospital, London, UK.
authors.forename: Kefah
authors.initials: K
authors.lastname: Mokbel
mesh_terms: D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology*; D002448:Cell Adhesion / Q000235:genetics*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics*; D004553:Electric Conductivity; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D061986:MCF-7 Cells; D009361:Neoplasm Invasiveness / Q000235:genetics*
chemical_list: D051017:Apoptosis Regulatory Proteins; C091572:DAP protein, human