interesting.....
Proc Natl Acad Sci U S A. 2015 Oct 28. pii: 201520032. [Epub ahead of print]
HIF-1 regulates CD47 expression in breast cancer cells to promote evasion of phagocytosis and maintenance of cancer stem cells.
Zhang H1, Lu H2, Xiang L2, Bullen JW2, Zhang C2, Samanta D2, Gilkes DM3, He J4, Semenza GL5.
1Department of Breast Surgery, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205;2Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205;3Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205;4Department of Breast Surgery, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China;5Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; Department of Radiation Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205 gsemenza@jhmi.edu.
Increased expression of CD47 has been reported to enable cancer cells to evade phagocytosis by macrophages and to promote the cancer stem cell phenotype, but the molecular mechanisms regulating CD47 expression have not been determined. Here we report that hypoxia-inducible factor 1 (HIF-1) directly activates transcription of the CD47 gene in hypoxic breast cancer cells. Knockdown of HIF activity or CD47 expression increased the phagocytosis of breast cancer cells by bone marrow-derived macrophages. CD47 expression was increased in mammosphere cultures, which are enriched for cancer stem cells, and CD47 deficiency led to cancer stem cell depletion. Analysis of datasets derived from thousands of patients with breast cancer revealed that CD47 expression was correlated with HIF target gene expression and with patient mortality. Thus, CD47 expression contributes to the lethal breast cancer phenotype that is mediated by HIF-1. |
