Tumor necrosis-initiated complement activation stimulates proliferation of medulloblastoma cells
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Objective and design
We sought to determine the effect of necrosis-induced activation of the complement protein C3 in medulloblastoma.
Twelve medulloblastoma surgical specimens were evaluated for complement activation using immunohistochemistry, with H&E stains performed on adjacent tissue sections to determine the relationship of complement activation to necrotic tissue. Flow cytometry and Western blot were performed on three established medulloblastoma lines and one surgically-procured cell culture to determine expression of C3a receptor (C3aR) in medulloblastoma. In vitro proliferation of siRNA C3aR knockdown cells was compared to that of control siRNA cells with cell line Daoy.
Three surgical specimens were found to have necrosis on H&E sections. In each case, iC3b staining was identified on adjacent sections, limited to the necrotic region. In no case did necrosis occur without iC3b staining on adjacent sections. C3aR protein was demonstrated on both the three established cell lines and on the surgical culture. Proliferation assays of Daoy cells with siRNA knockdown vs. control siRNA revealed significantly reduced proliferation at 72 h (p = 0.001).
Necrosis is associated with complement activation in medulloblastoma. Medulloblastoma cells express C3aR, and siRNA-mediated knockdown of C3aR inhibits proliferation of these cells in vitro.
KeywordsMedulloblastoma Complement Necrosis Proliferation
Phillip Bonney was supported by an Oklahoma Shared Clinical and Translational Resources Summer Scholars Program Grant. This study was partially supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20 GM103639 for the use of Histology and Immunohistochemistry Core, which provided staining, immunohistochemistry, and photographic services. We would like to acknowledge Megan Lerner, of the University of Oklahoma, Department of Surgery, for her assistance with immunohistochemical staining. We thank the Peggy and Charles Stephenson Cancer Center at the University of Oklahoma, Oklahoma City, OK and an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20 GM103639 for the use of Histology and Immunohistochemistry Core, which provided staining, immunohistochemistry, and photographic services.
Conflict of interest
The authors declare that they have no conflict of interest.
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