AEW-541

The insulin-like growth factor (IGF) signaling system comprises functionally specific ligands (IGF-I and IGF-II), receptor (IR), and binding proteins (IGFBP). IGFs are activated by binding to their receptor, IGF-IR, which is a tyrosine kinase receptor. This activation initiates signaling cascades such as PI3K/Akt and MAPK/ErK pathways, which are essential for cell proliferation, differentiation, and survival. Growing evidence links the IGF system to various hematological disorders, yet comprehensive reviews on its role in Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are limited. To advance understanding in this area, we aim to summarize the emerging evidence on the involvement of IGF signaling in the pathogenesis of MDS and AML. Specifically, we highlight how dysregulation of IGF-I, IGF-IR, and IGFBPs contributes to disease progression, encompassing clonal hematopoietic abnormalities, ineffective hematopoiesis in MDS, and the development of AML. The potential therapeutic implications of targeting the IGF signaling pathway, including the role of NVP-AEW541 and NVP-ADW742 effectively suppressing AML cell proliferation and enhancing chemotherapy sensitivity, are also explored. By integrating current findings, this review provides novel insights into the mechanistic role of IGF signaling in MDS and AML and its therapeutic implications, thereby guiding future research and potential clinical applications. Given the challenges, such as pathway redundancy and therapy resistance, further investigations are necessary to validate IGF-targeted therapies and optimize their clinical utility in hematologic malignancies.

To explore whether Ph⁺ acute lymphoblastic leukemia (ALL) cell line SUP-B15 treated with imatinib occurs a tolerant status charactered by cell proliferation suppression but apoptotic resistance, then evaluate whether IGF1-R inhibitor AEW541 can break this tolerance, and further explain its mechanisms.

SUP-B15 cells were treated with different concentrations of imatinib or AEW541. Cell proliferation was assayed by Deep Blue, and apoptotic cells were determined by Annexin V/7-AAD staining. Apoptotic rate was measured by flow cytometry after co-treatment of imatinib and AEW541. Western blot was used to evaluate ABL downstream signals, including the phosphorylation of STAT5, ERK1/2, and AKT, as well as to detect cleaved caspase-3 and PARP1, the molecular signatures of apoptosis. Furthermore, an inhibitor of STAT5 or MEK-ERK1/2 was used to confirm the key mechanism of the combination of imatinib and AEW541 induced SUP-B15 cell apoptosis.

Imatinib monotherapy effectively suppressed the proliferation of SUP-B15 cells, but did not induce significant increase of apoptotic rate, leading to occurrence of tolerant status. AEW541 monotherapy did not dramatically affect the proliferation and apoptosis of SUP-B15 cells, but significantly increased apoptotic rate of SUP-B15 cells and cleavage of caspase-3 and PARP1 when combined with imatinib simultaneously. A combination of imatinib and AEW541 reduced STAT5 and ERK1/2 phosphorylation as compared with imatinib monotherapy in SUP-B15 cells, but had no impact on AKT phosphorylation.Apoptosis could be induced by STAT5 inhibitor AC-4-130, but not by MEK-ERK1/2 inhibitor trametinib in SUP-B15 cells.

SUP-B15 cells treated with imatinib can establish drug tolerance. IGF1-R inhibitor AEW541 can further reduce STAT5 activation, thereby boosting the effect of apoptotic induction of imatinib on SUP-B15 cells. This research may provide a new idear to overcome imatinib tolerance.