Promoted cell proliferation by connexin 30 gene transfection to head-and-neck cancer cell line

Background: There have been inconsistent results regarding the contribution of the connexin family of genes to tumor cell proliferation. Materials and Methods: We aimed to clarify the role of connexin 30 (Cx30), by transfecting three kinds of vectors that express either full length Cx30 (Cx30-Full), Cx30 devoid of C-terminal region (Cx30-DelC) or Cx30 C-terminal region (Cx30-CT), in HSC-4, a head-and-neck cancer cell line. Results: Transfected Cx30-Full was localized on the plasma membrane, while Cx30-DelC and Cx30-CT was expressed in the cytoplasm or circumnuclear sites. We studied the effect on the growth rate followed by immunostaining with anti-Ki-67 (MIB-1). The MIB indices of HSC-4 cells transfected with Cx30-Full and Cx30-DelC, but not Cx30-CT were shown to be significantly higher than that of the controls. Conclusion: Our results demonstrated that Cx30 enhanced the proliferation of HSC-4 cells and the proliferating activity was considered to be achieved without the transport of the protein onto the plasma membrane.