kw-2449 and Leukemia--Myeloid--Acute

Aberrant activation of FMS-like tyrosine receptor kinase 3 (FLT3) is implicated in the pathogenesis of acute myeloid leukemia (AML) in 20-30% of patients. In this study we identified a highly selective (phenylethenyl)quinazoline compound family as novel potent inhibitors of the FLT3-ITD and FLT3-D835Y kinases. Their prominent effects were confirmed by biochemical and cellular proliferation assays followed by mice xenograft studies. Our modelling experiments and the chemical structures of the compounds predict the possibility of covalent inhibition. The most effective compounds triggered apoptosis in FLT3-ITD AML cells but had either weak or no effect in FLT3-independent leukemic and non-leukemic cell lines. Our results strongly suggest that our compounds may become therapeutics in relapsing and refractory AML disease harboring various ITD and tyrosine kinase domain mutations, by their ability to overcome drug resistance.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Discovery; Drug Screening Assays, Antitumor; fms-Like Tyrosine Kinase 3; Humans; Leukemia, Myeloid, Acute; Molecular Structure; Mutation; Protein Kinase Inhibitors; Pyrimidines; Structure-Activity Relationship

Kinase inhibitors are important cancer therapeutics. Polypharmacology is commonly observed, requiring thorough target deconvolution to understand drug mechanism of action. Using chemical proteomics, we analyzed the target spectrum of 243 clinically evaluated kinase drugs. The data revealed previously unknown targets for established drugs, offered a perspective on the "druggable" kinome, highlighted (non)kinase off-targets, and suggested potential therapeutic applications. Integration of phosphoproteomic data refined drug-affected pathways, identified response markers, and strengthened rationale for combination treatments. We exemplify translational value by discovering SIK2 (salt-inducible kinase 2) inhibitors that modulate cytokine production in primary cells, by identifying drugs against the lung cancer survival marker MELK (maternal embryonic leucine zipper kinase), and by repurposing cabozantinib to treat FLT3-ITD-positive acute myeloid leukemia. This resource, available via the ProteomicsDB database, should facilitate basic, clinical, and drug discovery research and aid clinical decision-making.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cytokines; Drug Discovery; fms-Like Tyrosine Kinase 3; Humans; Leukemia, Myeloid, Acute; Lung Neoplasms; Mice; Molecular Targeted Therapy; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Proteomics; Xenograft Model Antitumor Assays

We examined in vivo FLT3 inhibition in acute myeloid leukemia patients treated with chemotherapy followed by the FLT3 inhibitor lestaurtinib, comparing newly diagnosed acute myeloid leukemia patients with relapsed patients. Because we noted that in vivo FLT3 inhibition by lestaurtinib was less effective in the relapsed patients compared with the newly diagnosed patients, we investigated whether plasma FLT3 ligand (FL) levels could influence the efficacy of FLT3 inhibition in these patients. After intensive chemotherapy, FL levels rose to a mean of 488 pg/mL on day 15 of induction therapy for newly diagnosed patients, whereas they rose to a mean of 1148 pg/mL in the relapsed patients. FL levels rose even higher with successive courses of chemotherapy, to a mean of 3251 pg/mL after the fourth course. In vitro, exogenous FL at concentrations similar to those observed in patients mitigated FLT3 inhibition and cytotoxicity for each of 5 different FLT3 inhibitors (lestaurtinib, midostaurin, sorafenib, KW-2449, and AC220). The dramatic increase in FL level after chemotherapy represents a possible obstacle to inhibiting FLT3 in this clinical setting. These findings could have important implications regarding the design and outcome of trials of FLT3 inhibitors and furthermore suggest a rationale for targeting FL as a therapeutic strategy.

Topics: Antineoplastic Agents; Benzenesulfonates; Carbazoles; Cells, Cultured; Drug Antagonism; fms-Like Tyrosine Kinase 3; Furans; Humans; Indazoles; Inhibitory Concentration 50; Leukemia, Myeloid, Acute; Membrane Proteins; Multicenter Studies as Topic; Niacinamide; Phenylurea Compounds; Piperazines; Protein Kinase Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Sorafenib; Staurosporine; Treatment Outcome

We examined 6 different FMS-like tyrosine kinase-3 (FLT3) inhibitors (lestaurtinib, midostaurin, AC220, KW-2449, sorafenib, and sunitinib) for potency against mutant and wild-type FLT3, as well as for cytotoxic effect against a series of primary blast samples obtained from patients with acute myeloid leukemia (AML) harboring internal tandem duplication (FLT3/ITD) mutations. We found that inhibition of FLT3 autophosphorylation in a FLT3/ITD specimen does not always induce cell death, suggesting that some FLT3/ITD AML may not be addicted to FLT3 signaling. Relapsed samples and samples with a high mutant allelic burden were more likely to be responsive to cytotoxicity from FLT3 inhibition compared with the samples obtained at diagnosis or those with a low mutant allelic burden. These FLT3 inhibitors varied to a considerable degree in their selectivity for FLT3, and this selectivity influenced the cytotoxic effect. These results have important implications for the potential therapeutic use of FLT3 inhibitors in that patients with newly diagnosed FLT3-mutant AML might be less likely to respond clinically to highly selective FLT3 inhibition.

Topics: Alleles; Antineoplastic Agents; Benzenesulfonates; Benzothiazoles; Carbazoles; Cell Death; Cell Line, Tumor; Drug Resistance, Neoplasm; fms-Like Tyrosine Kinase 3; Furans; Humans; Indazoles; Indoles; Leukemia, Myeloid, Acute; Mutation; Niacinamide; Phenylurea Compounds; Phosphorylation; Piperazines; Pyridines; Pyrroles; Sorafenib; Staurosporine; Sunitinib