Project description:Doublecortin like kinase 1 (DCLK1) is an understudied kinase that is upregulated in a wide range of cancers, including pancreatic ductal adenocarcinoma (PDAC). However, little is known about its potential as a therapeutic target. We leveraged chemoproteomic profiling and structure-based design to develop the first selective, in vivo-compatible chemical probe of the DCLK1 kinase domain, DCLK1-IN-1. We demonstrate activity of DCLK1-IN-1 against clinically relevant patient-derived PDAC organoid models and use a combination of RNA sequencing, proteomics and phosphoproteomics analysis to reveal that DCLK1 inhibition modulates proteins and pathways associated with cell motility in this context. DCLK1-IN-1 will serve as a versatile tool to investigate DCLK1 biology and establish its role in cancer.
Project description:Exploiting an Asp-Glu “switch” in glycogen synthase kinase 3 to design paralog selective inhibitors for use in acute myeloid leukemia: Genome-wide transcriptional profiles for the GSK3α selective inhibitor BRD0507 and for the GSK3α/β dual inhibitor BRD0320 Glycogen synthase kinase 3 (GSK3), a key regulatory kinase in the WNT pathway, remains a therapeutic target of interest in many diseases. While dual GSK3α/β inhibitors have entered clinical trials, none has successfully translated to clinical application. Mechanism-based toxicities, driven in part by the inhibition of both GSK3 paralogs and subsequent β-catenin stabilization, are a concern in the translation of this target class to cancer therapy, particularly for the treatment of acute myeloid leukemia (AML). Knockdown of GSK3α or GSK3β individually does not increase β-catenin in certain cellular subtypes and offers a conceptual resolution to targeting GSK3: paralog-selective inhibition. However, only inadequate chemical tools exist. The design of selective ATP competitive inhibitors poses a drug discovery challenge due to the high homology (95% identity, 100% similarity) in their ATP binding domains. Taking advantage of an Asp133®Glu196 “switch” in their hinge binding domains, we present a rational design strategy towards the discovery of a paralog selective set of GSK3 inhibitors. These first-in-class GSK3α and GSK3β selective inhibitors provided insights into GSK3 targeting in AML where GSK3α has been identified as a therapeutic target using genetic approaches. Our GSK3α selective compound (BRD0705) inhibits kinase function and does not stabilize β-catenin, mitigating potential neoplastic concerns. BRD0705 induces myeloid differentiation and impairs colony formation in AML cells while no effect is observed on normal hematopoietic cells. Moreover, BRD0705 impairs leukemia initiation and prolongs survival in AML mouse models. These studies validate feasibility of paralog selective GSK3α inhibition offering a promising therapeutic approach in AML.
Project description:Exploiting an Asp-Glu “switch” in glycogen synthase kinase 3 to design paralog selective inhibitors for use in acute myeloid leukemia: Genome-wide transcriptional profile for the GSK3β selective inhibitor BRD3731. Glycogen synthase kinase 3 (GSK3), a key regulatory kinase in the WNT pathway, remains a therapeutic target of interest in many diseases. While dual GSK3α/β inhibitors have entered clinical trials, none has successfully translated to clinical application. Mechanism-based toxicities, driven in part by the inhibition of both GSK3 paralogs and subsequent β-catenin stabilization, are a concern in the translation of this target class to cancer therapy, particularly for the treatment of acute myeloid leukemia (AML). Knockdown of GSK3α or GSK3β individually does not increase β-catenin in certain cellular subtypes and offers a conceptual resolution to targeting GSK3: paralog-selective inhibition. However, only inadequate chemical tools exist. The design of selective ATP competitive inhibitors poses a drug discovery challenge due to the high homology (95% identity, 100% similarity) in their ATP binding domains. Taking advantage of an Asp133®Glu196 “switch” in their hinge binding domains, we present a rational design strategy towards the discovery of a paralog selective set of GSK3 inhibitors. These first-in-class GSK3α and GSK3β selective inhibitors provided insights into GSK3 targeting in AML where GSK3α has been identified as a therapeutic target using genetic approaches. Our GSK3α selective compound (BRD0705) inhibits kinase function and does not stabilize β-catenin, mitigating potential neoplastic concerns. BRD0705 induces myeloid differentiation and impairs colony formation in AML cells while no effect is observed on normal hematopoietic cells. Moreover, BRD0705 impairs leukemia initiation and prolongs survival in AML mouse models. These studies validate feasibility of paralog selective GSK3α inhibition offering a promising therapeutic approach in AML.
Project description:Cyclin dependent kinase 9 (CDK9), a key regulator of transcriptional elongation, has long been considered a promising target for cancer therapy, particularly for cancers driven by transcriptional dysregulation. However, despite promising early clinical data in blood cancers using pan-CDK inhibitors that potently inhibit CDK9 such as Dinaciclib and Flavopiridol, no selective CDK9 inhibitors have been clinically approved. Here we show that a multi-targeted CDK inhibitor can be used to develop a selective CDK9 degrader exemplified by THAL-SNS-032, a hetero-bifunctional molecule composed of SNS-032, a CDK2,7,9 inhibitor conjugated to thalidomide, a small molecule binder of Cereblon. We demonstrate that THAL-SNS-032 can recruit the E3 ubiquitin ligase Cereblon to CDK9 and induce its proteasome-mediated degradation. Treatment of cells with low nanomolar concentrations of THAL-SNS-032 resulted in rapid and efficient CDK9 degradation but did not affect levels of other SNS-032 targets, including CDK2 and CDK7. Consistent with this selective degradation phenotype, transcriptional profiling of THAL-SNS-032 indicated that its transcriptional effects were more similar to that of a selective CDK9 inhibitor, NVP2, than that of the nonselective SNS-032 parent compound. Moreover, THAL-SNS-032, in contrast to traditional CDK9 inhibitors, retained potent pro-apoptotic activity even after compound removal from cells. This suggests that degradation of CDK9 leads to prolonged cytotoxic effects as compared to CDK9 inhibition. Thus, our findings suggest that thalidomide conjugation may be a promising strategy for converting multi-targeting inhibitors into selective degraders, and that the pharmacological effects of kinase degradation can be distinct from kinase inhibition.
Project description:We sought to determine genes whose expression changed upon treatment with a selective inhibitor of class I PI3 kinase. Total of 6 samples: cells were treated with GDC-0941 at a concentration of 1mM for 6 hours (3 replicates) and control (3 replicates)
Project description:Investigation of the anti-tumor mechanism of tirabrutinib, a highly selective Bruton’s tyrosine kinase inhibitor, by transcriptomics