Background and Objectives. The Wilms' tumor gene (WT1) is aberrantly over-expressed in leukemic cells. Therefore, we wanted to study the effect of small interfering RNA (siRNA) targeting WT1 in leukemic cells and normal CD34-positive cells with regard to proliferation, induction of apoptosis, and cell differentiation. Furthermore, we wanted to evaluate whether the additional use of BCR-ABL siRNA could increase the antileukemic effects of WT1 siRNA in chronic myeloid leukemia (CML) cells. Design and Methods. We measured WT1 expression by reverse transcription polymerase chain reaction (RT-PCR) in various cell lines and in leukemic cells from patients, then transfected the cells with WT1-specific and BCR-ABL-specific siRNA before carrying out microarray analysis. We used the tunnel assay to measure apoptotic cells. Results. We observed a reduction of WT1 gene expression, measured by real-time RT-PCR, in all studied cell lines: K-562, Kasumi-1, MV 4-11 and NB-4, as well as in cells from AML and CML patients. The results also demonstrated that WT1 siRNA significantly induced apoptosis and inhibited proliferation in MV4-11 cells, NB-4 cells, Kasumi-1 cells (p<0.01) and in K-562 cells (p<0.02) versus controls. In normal CD34-positive cells, the proliferation was only slightly inhibited (by about 20%) and no induction of apoptosis was found. Combined transfection with WT1 and BCR-ABL siRNA together in K-562 cells increased the inhibition of the rate of proliferation and the rate of induced apoptosis compared to transfection with BCR-ABL siRNA or WT1 siRNA alone (p<0.01). We found that most genes involved in cell signaling and protein metabolism were regulated by the WT1 gene in K-562 cells in a microarray analysis. Interpretations and Conclusions. In conclusion, WT1 might be a suitable target for new therapeutic strategies using siRNA in leukemic cells.
Interim results of a randomised study performed by the intergruppo italiano linfomi (IIL) comparing R-chop and R-mini-ceop in a population of elderly patients (over 65) with diffuse large B cell lymphoma (DLCL) / F. Merli, S. Luminari, B. Botto, L. Baldini, G. Rossi, C. Stelinato, P. Mazza, M. Liberati, F. Ilariucci, C. Broglia, A. Levis. - In: HAEMATOLOGICA. - ISSN 0390-6078. - 90:S3 (Abs P522)(2005), pp. 326-327. (Intervento presentato al 40. convegno Congresso of the Italian Society of Hematology tenutosi a Bergamo nel 2005).
Interim results of a randomised study performed by the intergruppo italiano linfomi (IIL) comparing R-chop and R-mini-ceop in a population of elderly patients (over 65) with diffuse large B cell lymphoma (DLCL)
L. Baldini;
2005
Abstract
Background and Objectives. The Wilms' tumor gene (WT1) is aberrantly over-expressed in leukemic cells. Therefore, we wanted to study the effect of small interfering RNA (siRNA) targeting WT1 in leukemic cells and normal CD34-positive cells with regard to proliferation, induction of apoptosis, and cell differentiation. Furthermore, we wanted to evaluate whether the additional use of BCR-ABL siRNA could increase the antileukemic effects of WT1 siRNA in chronic myeloid leukemia (CML) cells. Design and Methods. We measured WT1 expression by reverse transcription polymerase chain reaction (RT-PCR) in various cell lines and in leukemic cells from patients, then transfected the cells with WT1-specific and BCR-ABL-specific siRNA before carrying out microarray analysis. We used the tunnel assay to measure apoptotic cells. Results. We observed a reduction of WT1 gene expression, measured by real-time RT-PCR, in all studied cell lines: K-562, Kasumi-1, MV 4-11 and NB-4, as well as in cells from AML and CML patients. The results also demonstrated that WT1 siRNA significantly induced apoptosis and inhibited proliferation in MV4-11 cells, NB-4 cells, Kasumi-1 cells (p<0.01) and in K-562 cells (p<0.02) versus controls. In normal CD34-positive cells, the proliferation was only slightly inhibited (by about 20%) and no induction of apoptosis was found. Combined transfection with WT1 and BCR-ABL siRNA together in K-562 cells increased the inhibition of the rate of proliferation and the rate of induced apoptosis compared to transfection with BCR-ABL siRNA or WT1 siRNA alone (p<0.01). We found that most genes involved in cell signaling and protein metabolism were regulated by the WT1 gene in K-562 cells in a microarray analysis. Interpretations and Conclusions. In conclusion, WT1 might be a suitable target for new therapeutic strategies using siRNA in leukemic cells.
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