3H-pyrazolo[4,3-f]quinoline-containing compounds as selective and tunable protein kinase inhibitors - Project summary: Acute myeloid leukemia (AML) is a devastating cancer with limited options, despite decades of intensive searches for curative therapeutics. The average 5-year survival of AML is about 30% (for all patients) but for most elderly patients over 60 years, the 2-year survival rate is less than 5%. About 30% of AML patients harbor a mutated FLT3 kinase and these patients have the worst outcome. Midostaurin and gilteritinib, FLT3 inhibitors were approved in 2017 and 2018 respectively. Crenolanib another FLT3 inhibitor is in advanced phase III clinical trials, whereas quizartinib was approved in Japan but failed to gain FDA approval. However patients on all of the four FLT3 inhibitors ultimately relapse due to secondary mutations in the FLT3 kinase (such as FLT3-ITD, D835 and F691 mutants) and other compensatory resistance mechanisms. Breast cancer has an average 5-year survival rate is 93% for stage I and II but for a small but significant percentage (15-20%) of breast cancer patients, who harbor hormone refractory cancer (called triple negative breast cancer, TNBC), there are few therapeutic options. Clearly new therapeutics, which are effective against AML and TNBC cancers, are needed. The PIs have identified novel 3H-pyrazolo[4,3-f]quinoline-based kinase inhibitors, synthesized in only a single flask operation, that potently inhibit FLT3 and/or CDK2 or CDK12/13 or CDK18. The selectivity for these kinases depend on the substitution pattern of the 3H-pyrazolo[4,3-f]quinoline core. CDK12/13 and CDK18 are involved in the cell's response to DNA damage and the inhibition of these kinases lead to BRCAness in various cancers, making such cancers sensitive to agents that damage DNA or inhibit DNA damage repair, such as doxorubicin or PARP inhibitors respectively. The overall goal of this project is to optimize these interesting new class of kinase inhibitors for possible translation into AML and breast therapeutics. In aim 1, second-generation 3H- pyrazolo[4,3-f]quinoline-based compounds, (first-generation compounds have already shown impressive in-vivo efficacy against AML in vivo), will be biochemically characterized and evaluated in vivo (Aim 3). Additionally new chemistries will be used to make third-generation 3H-pyrazolo[4,3-f]quinoline-based kinase inhibitors that have better drug-like properties. Aim 2 characterize how these new potent anti-proliferative compounds affect protein phosphorylation in cancer cells and to determine the potencies of the compounds at killing various AML cell lines, which are resistant to current therapies such as gilteritinib, and triple negative breast cancer cell lines in vitro. In aims 3, the PIs will evaluate the in-vivo efficacies of lead compounds against AML and breast tumors. project, novel agents against AML and breast cancer, which inhibit traditional FLT3 (AML) as well as CDK12/13 and CDK18, which are interesting new cancer targets with no approved drugs that target them.
