Project description:Dopamine receptor (DRD) antagonist thioridazine (TDZ) has been traditionally prescribed as an anti-psychotic drug. Recent observations have revealed anti-neoplastic effects of TDZ in a variety of neural and non-neural cancers including acute myeloid leukemia (AML). However, the basis of TDZ effects on transformed tissues is not fully understood. We used AML as a model system to study the anti-neoplastic properties of TDZ, as well as the downstream mechanism of action for DRDs in the context of cancer. Our study defines a role for DRDs in regulating neoplastic properties and suggests DRD2 as an attractive therapeutic target for 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: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:We used Agilent human gene expression arrays to test whether Capridine, a chemotherapeutic agent with specificity towards prostate cancer, deregulates the genomic fabric of acute myeloyd leukemia in HL-60 cells. This cell line was derived at the National Cancer Institute from a 36-year-old woman with acute promyelocytic leukemia. We found that Capridine down-regulates the pathways responsible for formation of hematopoietic progenitor cells, for anti-apoptosis and for proliferation of clonal neoplastic cells. Our results indicates the therapeutic potential of Capridine against acute myeloid leukemia. Two-conditions: HO = not treated, HA = Capridine-treated HL-60 cells. Four biological replicates of each condition. Differently labeled biological replicates were cohybridized with each array. Results of similarly labeled different conditions were compared then averaged for the two fluorescent labels. For instance: HO1 & HO3 were compared with HA1 & HA3, HO2 & HO4 were compared with HA2 & + HA4, and the results of the comparisons averaged. This design uses 100% of the resources, has a better normlaiztion and allows all possible comparisons among the conditions.
Project description:Chimeric antigen receptor (CAR) therapy targeting CD19 yielded remarkable outcomes in patients with acute lymphoblastic leukemia. To identify potential CAR targets in acute myeloid leukemia (AML), we probed the AML surfaceome for over-expressed molecules with potentially tolerable systemic expression. We integrated large transcriptomics and proteomics data sets from malignant and normal tissues, and developed an algorithm to identify potential targets expressed in leukemia stem cells, but not in normal CD34+CD38– hematopoietic cells, T cells or vital tissues. As these investigations did not uncover candidate targets with a profile as favorable as CD19, we developed a generalizable combinatorial targeting strategy fulfilling stringent efficacy and safety criteria. Our findings indicate that several target pairings hold great promise for CAR therapy of AML.
Project description:we show that YBX1 is specifically required for maintaining myeloid leukemia cell survival but is dispensable for normal hematopoiesis. We found that expression of YBX1 is significantly upregulated in myeloid leukemia cells, and deletion of YBX1 significantly induces apoptosis, coupled with reduced proliferation and impaired leukemic capacity of primary human and mouse acute myeloid leukemia (AML) cells in vitro and in vivo. Loss of YBX1 does not obviously affect normal hematopoiesis. Mechanistically, YBX1 interacts with IGF2BPs and stabilizes m6A-tagged RNA. Moreover, YBX1 deficiency promotes mRNA decay in an m6A-dependent manner, which contributes to the defective survival due to YBX1 deletion. Thus, our findings uncover a selective and critical role of YBX1 in maintaining myeloid leukemia survival that might provide a rationale for the therapeutic targeting of YBX1 in myeloid leukemia.
Project description:we show that YBX1 is specifically required for maintaining myeloid leukemia cell survival but is dispensable for normal hematopoiesis. We found that expression of YBX1 is significantly upregulated in myeloid leukemia cells, and deletion of YBX1 significantly induces apoptosis, coupled with reduced proliferation and impaired leukemic capacity of primary human and mouse acute myeloid leukemia (AML) cells in vitro and in vivo. Loss of YBX1 does not obviously affect normal hematopoiesis. Mechanistically, YBX1 interacts with IGF2BPs and stabilizes m6A-tagged RNA. Moreover, YBX1 deficiency promotes mRNA decay in an m6A-dependent manner, which contributes to the defective survival due to YBX1 deletion. Thus, our findings uncover a selective and critical role of YBX1 in maintaining myeloid leukemia survival that might provide a rationale for the therapeutic targeting of YBX1 in myeloid leukemia.