PFKFB3 Is a Crucial Target in the Treatment of Tyrosine Kinase Inhibitor Resistant Chronic Myelogenous Leukemia

Resistance to the BCR-ABL tyrosine kinase inhibitor (TKI) imatinib mesylate (IM) remains challenge for the treatment of chronic myeloid leukemia (CML). IM resistance often results from unknown mechanisms with wild type BCR-ABL that have no effects on TKIs binding to ABL kinase domain. The basis of such BCR-ABL-independent IM resistance remains to be elucidated. To gain insight into BCR-ABL-independent IM resistance mechanisms, we performed an initial bioinformatics screen on over represented CML genes, followed by a quantitative PCR screen of genes that were elevated in TKIs resistant CML samples. We identified a total of 33 candidate genes that were highly expressed in TKIs resistant patients. Among these genes, 6-Phosphofructo-2-Kinase/Fructose-2,6-Biphosphatase 3 (PFKFB3) controlling the limiting step of glycolysis, was found to strongly associated with TKIs resistance. RNA interference of the expression of PFKFB3 and pharmacological inhibition of its kinase activity markedly increased the sensitivity of TKIs resistant CML cells to TKIs. Furthermore, pharmacological inhibition of PFKFB3 prevented CML cells growth and significantly improved the survival of both allograft and xenograft CML mice. ChIP-seq data analysis combined with subsequent knockdown experiment demonstrated that the Ets transcription factor PU.1 regulates the elevated expression of PFKFB3 in TKIs resistant CML cells. Collectively, our results identify a therapeutically targetable mechanism of BCR-ABL-independent TKIs resistant CML.