1. Epstein-Barr virus can infect B-chronic lymphocytic leukemia cells but it does not orchestrate the cell cycle regulatory proteins
- Author
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Maeda A, Bandobashi K, Nagy N, Teramoto N, Péter Gogolák, Pokrovskaja K, Székely L, Björkholm M, Klein G, and Klein E
- Subjects
B-Lymphocytes ,Herpesvirus 4, Human ,Tumor Suppressor Proteins ,Cell Cycle Proteins ,Leukemia, Lymphocytic, Chronic, B-Cell ,Retinoblastoma Protein ,Proto-Oncogene Proteins c-myc ,Viral Proteins ,Epstein-Barr Virus Nuclear Antigens ,Cyclins ,Tumor Cells, Cultured ,Animals ,Cyclin D2 ,Humans ,Cyclin D3 ,Phosphorylation ,Cells, Cultured ,Cyclin-Dependent Kinase Inhibitor p27 - Abstract
To understand the mechanism for the refractoriness of B-chronic lymphocytic leukemia (B-CLL) cells for Epstein-Barr virus (EBV)-induced immortalization.Cultures were initiated with EBV-infected tonsillar B and B-CLL cells. Expression of EBNA-2 and some of the key players regulating G1/S phase transition such as c-myc expression, phosphorylation of Rb protein, expression of G1 cyclins, and the cyclin-dependent kinase inhibitor p27 were followed.In line with earlier studies, EBV infection induced c-myc expression, pRb phosphorylation, D2 and D3 expression, and disappearance of p27 in normal B cells. In contrast, EBV-infected B-CLL cells remained resting and they did not express c-myc; cyclin D2, ppRb and cyclin D3 were seen only in occasional cells. Importantly, p27 expression was maintained.In B-CLL cells, the expression of the EBV-encoded nuclear proteins EBNAs is not followed by entrance to the cell cycle. Thus, the difference in the interaction of EBV-normal B cells and EBV-B-CLL cells is already apparent early after infection.