PBK/TOPK is a novel mitotic kinase which is upregulated in Burkitt's lymphoma and other highly proliferative malignant cells.
PBK/TOPK is a recently cloned serine/threonine kinase which is phosphorylated during mitosis. Earlier work indicated that this kinase is upregulated in a Burkitt's lymphoma cell line (GA-10). To determine whether PBK/TOPK is upregulated in other mitotically active neoplastic cell lines and tissues, Northern analysis was performed on a panel of malignant cell lines and on clinical samples from patients with leukemia or lymphoma. While PBK/TOPK mRNA was not detectable in normal peripheral blood cells and was weakly expressed in hyperplastic tonsillar B-cells, significantly higher levels of mRNA were detected in 8 Burkitt's lymphoma cell lines, 10 other neoplastic cell lines, and 2 clinical samples-one derived from a patient with ALL and a second derived from a patient with relapsed myeloma. In addition, Northern analysis of fetal tissues showed upregulated expression of PBK/TOPK in fetal kidney, lung, spleen, brain, and testis. These data suggest that PBK/TOPK expression is increased in highly proliferative malignant cells and during normal fetal development.
Simons-Evelyn
M
M
Greenebaum Cancer Center, University of Maryland, 22 South Greene Street, Baltimore, Maryland 21201, USA.
Bailey-Dell
K
K
Toretsky
J A
JA
Ross
D D
DD
Fenton
R
R
Kalvakolanu
D
D
Rapoport
A P
AP
D000328:Adult; D001402:B-Lymphocytes / Q000201:enzymology; D001773:Blood Cells / Q000201:enzymology; D002051:Burkitt Lymphoma / Q000201:enzymology* / Q000473:pathology; D005333:Fetus / Q000166:cytology / Q000201:enzymology; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases; D014066:Palatine Tonsil / Q000166:cytology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D012333:RNA, Messenger; D017346:Protein Serine-Threonine Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; C409022:PDZ-binding kinase