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.

Flavopiridol induces apoptosis and caspase-3 activation of a newly characterized Burkitt's lymphoma cell line containing mutant p53 genes.

Burkitt's lymphoma cell lines have been important in vitro models for studying the pathogenesis of Burkitt's lymphoma (BL) and for exploring new treatment strategies. A new EBV(-) Burkitt's lymphoma cell line (GA-10) was established from a patient with a clinically aggressive, chemorefractory BL and characterized. Although functional p-glycoprotein could not be demonstrated by dye-efflux assays, both p53 genes were mutated in the GA-10 cells, perhaps contributing to the resistant phenotype of the original neoplasm.

Characterization of the mouse Nktr gene and promoter.

We have cloned and determined the structure of the 5' region of the mouse Nktr gene located on the distal end of mouse chromosome 9. This gene encodes an NK-cell-specific 150-kDa protein (NK-TR) homologous to cyclophilin, Nopp140, and SR-containing proteins. NK-TR expression is important for maintaining the lytic activity of natural killer cells.