Loss or Inhibition of Stromal-Derived PIGF Prolongs Survival of Mice with Imatinib-Resistant Bcr-Abl1+ Leukemia

Imatinib has revolutionized the treatment of BCR-ABL1(+) chronic myeloid leukemia (CML), but, in most patients, some leukemia cells persist despite continued therapy, while others become resistant. Here, we report that PIGF levels are elevated in CML and that PIGF produced by bone marrow stromal cells (BMSCs) aggravates disease severity. CML cells foster a soil for their own growth by inducing BMSCs to upregulate PIGF, which not only stimulates BM angiogenesis, but also promotes CML proliferation and metabolism, in part independently of BCR-ABL1 signaling. Anti-PIGF treatment prolongs survival of imatinib-sensitive and -resistant CML mice and adds to the anti-CML activity of imatinib. These results may warrant further investigation of the therapeutic potential of PIGF inhibition for (imatinib-resistant) CML.