WT1 protein expression in slowly proliferating myeloid leukemic cell lines is scarce throughout the cell cycle with a minimum in G0/G1 phase

TY - JOUR

T1 - WT1 protein expression in slowly proliferating myeloid leukemic cell lines is scarce throughout the cell cycle with a minimum in G0/G1 phase

AU - Kerst, Gunter

AU - Bergold, Nina

AU - Viebahn, Susanne

AU - Gieseke, Friederike

AU - Kalinova, Marketa

AU - Trka, Jan

AU - Handgretinger, Rupert

AU - Müller, Ingo

PY - 2008/9

Y1 - 2008/9

N2 - Wilms' tumor gene 1 (WT1) is overexpressed in various hematological malignancies and has been proposed as a target for minimal residual disease (MRD) detection and for immunotherapy. Although WT1 is known as a key molecule for tumor cell proliferation, the expression pattern of WT1 in leukemic cells in dependency of proliferation has not yet been investigated. Furthermore, WT1 expression was mostly studied by reverse transcriptase PCR and the expression of WT1 protein has not been extensively studied. Here, we analyzed WT1 protein expression in the human myeloid leukemia cell lines K562 and HL-60 by indirect immunofluorescence and flow cytometry. Both cell lines exhibited varying nuclear WT1 immunoreactivity pointing to a cell cycle-dependent and/or proliferation-dependent WT1 expression. In rapidly proliferating cells high levels of WT1 protein were detected by flow cytometry. A reduced proliferation rate was associated with a low WT1 protein expression and an accumulation of cells in G(0)/G(1) phase. During G(0)/G(1) phase cells expressed WT1 at a lower level than in S or G(2)/M phase. Moreover, WT1 expression was diminished in all cell cycle phases in slowly proliferating cells. We conclude that WT1 protein expression is dependent on the cell cycle phase as well as on the proliferation rate. This finding might be relevant for MRD studies and immunotherapeutic strategies targeting WT1.

AB - Wilms' tumor gene 1 (WT1) is overexpressed in various hematological malignancies and has been proposed as a target for minimal residual disease (MRD) detection and for immunotherapy. Although WT1 is known as a key molecule for tumor cell proliferation, the expression pattern of WT1 in leukemic cells in dependency of proliferation has not yet been investigated. Furthermore, WT1 expression was mostly studied by reverse transcriptase PCR and the expression of WT1 protein has not been extensively studied. Here, we analyzed WT1 protein expression in the human myeloid leukemia cell lines K562 and HL-60 by indirect immunofluorescence and flow cytometry. Both cell lines exhibited varying nuclear WT1 immunoreactivity pointing to a cell cycle-dependent and/or proliferation-dependent WT1 expression. In rapidly proliferating cells high levels of WT1 protein were detected by flow cytometry. A reduced proliferation rate was associated with a low WT1 protein expression and an accumulation of cells in G(0)/G(1) phase. During G(0)/G(1) phase cells expressed WT1 at a lower level than in S or G(2)/M phase. Moreover, WT1 expression was diminished in all cell cycle phases in slowly proliferating cells. We conclude that WT1 protein expression is dependent on the cell cycle phase as well as on the proliferation rate. This finding might be relevant for MRD studies and immunotherapeutic strategies targeting WT1.

KW - Cell Cycle

KW - Cell Proliferation

KW - Flow Cytometry

KW - Fluorescent Antibody Technique, Indirect

KW - HL-60 Cells

KW - Humans

KW - K562 Cells

KW - Leukemia, Myeloid

KW - WT1 Proteins

U2 - 10.1016/j.leukres.2008.03.006

DO - 10.1016/j.leukres.2008.03.006

M3 - SCORING: Journal article

C2 - 18457871

VL - 32

SP - 1393

EP - 1399

JO - LEUKEMIA RES

JF - LEUKEMIA RES

SN - 0145-2126

IS - 9

ER -