title: Apoptosis-induced cancer cell fusion: a mechanism of breast cancer metastasis.
abstract: Although cancer cell fusion has been suggested as a mechanism of cancer metastasis, the underlying mechanisms defining this process are poorly understood. In a recent study, apoptotic cells were newly identified as a type of cue that induces signaling via phosphatidylserine receptors to promote fusion of myoblasts. The microenvironment of breast tumors is often hypoxic, and because apoptosis is greatly increased in hypoxic conditions, we decided to investigate whether the mechanism of breast cancer cell fusion with mesenchymal stem/multipotent stromal cells (MSCs) involves apoptosis. We used a powerful tool for identification and tracking of hybrids based on bimolecular fluorescence complementation (BiFC) and found that breast cancer cells fused spontaneously with MSCs. This fusion was significantly enhanced with hypoxia and signaling associated with apoptotic cells, especially between nonmetastatic breast cancer cells and MSCs. In addition, the hybrids showed a significantly higher migratory capacity than did the parent cells. Taken together, these findings describe a mechanism by which hypoxia-induced apoptosis stimulates fusion between MSCs and breast tumor cells resulting in hybrids with an enhanced migratory capacity that may enable their dissemination to distant sites or metastases. In the long run, this study may provide new strategies for developing novel drugs for preventing cancer metastasis.
authors.affiliation: *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Felicite K
authors.initials: FK
authors.lastname: Noubissi
authors.affiliation: *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Ty
authors.initials: T
authors.lastname: Harkness
authors.affiliation: *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Alexander
authors.affiliation: *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA ogle@umn.edu.
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Ogle
mesh_terms: D017209:Apoptosis; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002459:Cell Fusion; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000378:metabolism* / Q000473:pathology; D009362:Neoplasm Metastasis; D015398:Signal Transduction
keywords: bimolecular fluorescence complementation; hybrid; hypoxia; mesenchymal stem cell; migration