Hodgkin Reed–Sternberg (H-RS) cell is the tumor cell of classical Hodgkin disease (cHD), and their characteristics are still unclear. KM-H2 was established as an H-RS cell line from pleural effusion of a patient with cHD. We investigated the implications of extracellular matrix (ECM) for adhesion and function of H-RS cell.Methods
Adhesion assay was carried out with the in situ crystal violet staining method. Cell staining was carried out using monoclonal antibodies conjugated with fluoro-dye. Stained cells were analyzed by a FACScan.Results
We seeded KM-H2 onto the gelatin-coated or non-coated dish. KM-H2 cultured on a non-coated dish grown as a floating cell and formed a cell cluster (referred to hereafter as fl-KM-H2). However, KM-H2 tightly adhered onto the surface of dish and achieved a cell spreading following cultivation on a gelatin-coated dish for 24 h (referred to hereafter as ad-KM-H2). When KM-H2 was cultured on a gelatin-coated well, the significant increase of the number of the adhesive cell was observed. Moreover, ad-KM-H2 abundantly expressed E-cadherin whereas fl-KM-H2 lacked the expression of E-cadherin. Because E-cadherin was widely accepted hallmark of mesenchymal-to-epithelial transition (MET), we concluded that gelatin could promote EMT in KM-H2. These MET of KM-H2 was also induced by type I collagen and fibronectin. However, type IV collagen and laminin failed to promote MET. In addition, we found that the P38 MAP kinase inhibitor (SB202190) could inhibit MET without loss of cell viability. On the contrary, the inhibitors of Erk or Akt could not inhibit MET of KM-H2. In addition, we revealed that Serine 910 of FAK was constitutively phosphorylated in KM-H2.Conclusion
ECM components could induce MET in KM-H2. Further investigation might become a milestone to explore an alternative molecular target for antitumor therapy.