Protein expression and cellular localization in two prognostic subgroups of diffuse large B-cell lymphoma: higher expression of ZAP70 and PKC-beta II in the non-germinal center group and poor survival in patients deficient in nuclear PTEN.
Patients diagnosed with diffuse large B-cell lymphoma (DLBCL) show varying responses to conventional therapy, and this might be contributed to the differentiation stage of the tumor B-cells. The aim of the current study was to evaluate a panel of kinases (ZAP70, PKC-beta I and II and phosphorylated PKB/Akt) and phosphatases (PTEN, SHP1 and SHP2) known to be frequently deregulated in lymphoid malignancies. De novo DLBCL cases were divided into two subgroups, the germinal center (GC) group (14/28) and the non-germinal center (non-GC) or activated B-cell (ABC) group (14/28). ZAP70 and PKC-beta II were expressed in a significantly higher percentage of tumor cells in the clinically more aggressive non-GC group compared with the prognostically favourable GC group. Also, the subcellular localization of PKC-beta I and II differed in DLBCL cells, with the PKC-beta I isoform being expressed in both the cytoplasm and nucleus, while PKC-beta II was found exclusively in the cytoplasm. Loss of nuclear PTEN correlated with poor survival in cases from both subgroups. In addition, five cell lines of DLBCL origin were analyzed for protein expression and for mRNA levels of PTEN and SHP1. For the first time, we show that ZAP70 is expressed in a higher percentage of tumor cells in the aggressive non-GC subgroup of DLBCL and that PKC-beta I and II are differently distributed in the two prognostic subgroups of de novo DLBCL.
Fridberg
Marie
M
Department of Tumor Biology, Lund University, Malmö University Hospital, Malmö, Sweden.
Servin
Anna
A
Anagnostaki
Lola
L
Linderoth
Johan
J
Berglund
Mattias
M
Söderberg
Ola
O
Enblad
Gunilla
G
Rosén
Anders
A
Mustelin
Tomas
T
Jerkeman
Mats
M
Persson
Jenny L
JL
Wingren
Anette Gjörloff
AG
D000368:Aged; D002467:Cell Nucleus / Q000378:metabolism*; D003953:Diagnosis-Related Groups; D005260:Female; D018858:Germinal Center / Q000378:metabolism*; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000145:classification / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D008297:Male; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D011379:Prognosis; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D016019:Survival Analysis; D046888:Tissue Array Analysis; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000378:metabolism*
D020033:Protein Isoforms; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human