Effect of NPM1 type B mutation on the proliferation, invasion and chemosensitivity of THP-1 leukemia cells.

Acute myeloid leukemia (AML) is the most malignant myeloid disorder in adults. AML with mutated nucleophosmin (NPM1) is regarded as an independent leukemia subtype. According to previous studies, the role of NPM1 gene A mutation in AML has been well established; however, another major type, NPM1 gene B type mutation (NPM1 MutB) has been rarely reported. In the present study, we found that overexpression of NPM1 MutB enhanced the proliferation and invasion of THP-1 AML cells through the regulation of TIMP-2, MMP-2, Ang-1, c-myc and CCND1; led to no significant change of apoptosis rate with the absence of chemotherapy agents, while enhanced the chemosensitivity of THP-1 AML cells to chemotherapy agents DNR and Ara-C through the regulation of Bax, Bcl-2 and caspase-3. Further, we revealed that NPM1 MutB overexpression reduced the NF-kappa B activity of THP-1 cells upon drug treatment. Taken together, we demonstrated the detailed functions of NPM1MutB in THP-1 proliferation, invasion, apoptosis and chemo-sensitivity. We provided a novel understanding of prognosis of patients carrying the NPM1 B mutation.