SOCS1 is significantly up-regulated in Nutlin-3-treated p53 wild-type B chronic lymphocytic leukemia (BCLL) samples and shows an inverse correlation with miR-155

The basal SOCS1 mRNA levels were significantly lower in p53 ^mutated BJAB and MAVER leukemic cell lines with respect to p53 ^wild-type SKW6.4 and JVM-2 leukemic cell lines, p53 ^wild-type primary B chronic lymphocytic leukemia (B-CLL) cells and primary normal peripheral blood mononuclear cells (PBMC). Moreover, the MDM2 small molecule inhibitor Nutlin-3 significantly increased the levels of SOCS1 mRNA in both primary p53^wild-type B-CLL cells as well as in p53 ^wild-type B leukemic cell lines, but not in p53^mutated B leukemic cell lines nor in primary PBMC. Of note, a significant inverse correlation was observed between SOCS1 mRNA and miR-155 levels in Nutlin-3-treated primary B-CLL cells and PBMC, suggesting that the miRNA-155/SOCS1 axis represents a potentially important therapeutic target of Nutlin-3 in B-CLL.