Upregulation of SOCS-1 by Nutlin-3 in acute myeloid leukemia cells but not in primary normal cells.
OBJECTIVE
It has been shown that SOCS-1 plays an important role in the proper control of cytokine/growth factor responses and acts as a tumor suppressor in acute myeloid leukemias. Therefore, the objective of the present study was to evaluate the in vitro effect of treatment with Nutlin-3, a small molecule inhibitor of the MDM2/p53 interaction, on the expression of the suppressor of cytokine signaling 1 in primary acute myeloid leukemia cells and in myeloid cell lines with differential p53 status.


METHODS
The expression of the suppressor of cytokine signaling 1 was quantitatively analyzed by real-time PCR in myeloid p53wild-type (OCI and MOLM) and p53null HL-60, leukemic cell lines, in patient-derived acute myeloid leukemia blasts, and in primary normal cell types, such as macrophages, endothelial cells, and bone marrow mesenchymal stem cells. The p53-dependence of the suppressor of cytokine signaling 1 upregulation that is induced by Nutlin-3 was analyzed in experiments performed using siRNA for p53, while the functional upregulation of the suppressor of cytokine signaling 1 was analyzed by assessing the levels of phosphorylated STAT-3.


RESULTS
Nutlin-3 significantly upregulated the transcription of the suppressor of cytokine signaling 1 in p53wild-type OCI and MOLM but not in p53deleted p53null HL60, myeloid leukemic cell lines, as well as in primary acute myeloid leukemia blasts. Conversely, and somewhat unexpectedly, Nutlin-3 did not modulate the suppressor of cytokine signaling 1 expression in primary normal macrophages, endothelial cells, and bone marrow mesenchymal stem cells. The p53-dependent upregulation of the suppressor of cytokine signaling 1 by Nutlin-3 was associated with the downregulation of phosphorylated STAT-3, a major molecular target of the suppressor of cytokine signaling 1.


CONCLUSIONS
Overall, our data suggest a potential role for the suppressor of cytokine signaling 1 as a therapeutic target of Nutlin-3 in p53 wild-type acute myeloid leukemias.
Surgery and Experimental Medicine and LTTA Centre, Department of Morphology, University of Ferrara, Ferrara, Italy, University of Ferrara, Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, Ferrara, Italy.
Veronica
V
Tisato
IRCCS "Burlo Garofolo", Institute for Maternal and Child Health, Trieste, Italy, Institute for Maternal and Child Health, IRCCS ''Burlo Garofolo'', Trieste, Italy.
Alessia
A
Norcio
Department of Life Sciences, University of Trieste, Trieste, Italy, University of Trieste, Department of Life Sciences, Trieste, Italy.
Claudio
C
Celeghini
Surgery and Experimental Medicine and LTTA Centre, Department of Morphology, University of Ferrara, Ferrara, Italy, University of Ferrara, Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, Ferrara, Italy.
Daniela
D
Milani
Surgery and Experimental Medicine and LTTA Centre, Department of Morphology, University of Ferrara, Ferrara, Italy, University of Ferrara, Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, Ferrara, Italy.
Arianna
A
Gonelli
Surgery and Experimental Medicine and LTTA Centre, Department of Morphology, University of Ferrara, Ferrara, Italy, University of Ferrara, Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, Ferrara, Italy.
Paola
P
Secchiero
D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000378:metabolism / Q000494:pharmacology*; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000378:metabolism; D022423:Myeloid Cells / Q000187:drug effects / Q000378:metabolism; D010879:Piperazines / Q000378:metabolism / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects*
D007093:Imidazoles; D010879:Piperazines; C108944:SOCS1 protein, human; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D016159:Tumor Suppressor Protein p53; C482205:nutlin 3