FOXP3 knockdown inhibits the proliferation and reduces NOTCH1 expression of T cell acute lymphoblastic leukemia cells.

Two T-ALL cell lines Jurkat and KOPT-K1, harboring activating NOTCH1 mutations, were transfected with small interfering RNA against FOXP3. Cell growth was assessed with a colorimetric assay and morphology was observed under a microscope. FOXP3 knockdown significantly reduced cell growth and induced morphological changes suggesting apoptosis. Quantitative polymerase chain reaction revealed that FOXP3 knockdown caused the downregulation of mRNA expression of NOTCH1 and HES1. These findings suggest that FOXP3 supports the growth of T-ALL cells although this can not be generalized because we examined only two cell lines. The observed growth suppression can be partly due to the downregulation of NOTCH1 signaling. FOXP3 may be a potential therapeutic target in T-ALL.