Design of the Firstâ inâ Class, Highly Potent Irreversible Inhibitor Targeting the Meninâ MLL Proteinâ Protein Interaction

The structureâ based design of Mâ 525 as the firstâ inâ class, highly potent, irreversible smallâ molecule inhibitor of the meninâ MLL interaction is presented. Mâ 525 targets cellular menin protein at subâ nanomolar concentrations and achieves low nanomolar potencies in cell growth inhibition and in the suppression of MLLâ regulated gene expression in MLL leukemia cells. Mâ 525 demonstrates high cellular specificity over nonâ MLL leukemia cells and is more than 30 times more potent than its corresponding reversible inhibitors. Mass spectrometric analysis and coâ crystal structure of Mâ 525 in complex with menin firmly establish its mode of action. A single administration of Mâ 525 effectively suppresses MLLâ regulated gene expression in tumor tissue. An efficient procedure was developed to synthesize Mâ 525. This study demonstrates that irreversible inhibition of menin may be a promising therapeutic strategy for MLL leukemia.Irreversible inhibitor Mâ 525 targets the meninâ MLL interaction. It is demonstrated that irreversible inhibition of menin is a promising therapeutic strategy for the treatment of MLL leukemia and may have advantages over reversible inhibitors.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141532/1/anie201711828.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141532/2/anie201711828-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141532/3/anie201711828_am.pd

Design of the Firstâ inâ Class, Highly Potent Irreversible Inhibitor Targeting the Meninâ MLL Proteinâ Protein Interaction

The structureâ based design of Mâ 525 as the firstâ inâ class, highly potent, irreversible smallâ molecule inhibitor of the meninâ MLL interaction is presented. Mâ 525 targets cellular menin protein at subâ nanomolar concentrations and achieves low nanomolar potencies in cell growth inhibition and in the suppression of MLLâ regulated gene expression in MLL leukemia cells. Mâ 525 demonstrates high cellular specificity over nonâ MLL leukemia cells and is more than 30 times more potent than its corresponding reversible inhibitors. Mass spectrometric analysis and coâ crystal structure of Mâ 525 in complex with menin firmly establish its mode of action. A single administration of Mâ 525 effectively suppresses MLLâ regulated gene expression in tumor tissue. An efficient procedure was developed to synthesize Mâ 525. This study demonstrates that irreversible inhibition of menin may be a promising therapeutic strategy for MLL leukemia.Der irreversible Inhibitor Mâ 525 greift an der Meninâ MLLâ Wechselwirkung an. Die irreversible Inhibition von Menin erweist sich als vielversprechende Strategie für die Behandlung von MLLâ Leukämie, mit möglichen Vorteilen gegenüber dem Einsatz reversibler Inhibitoren.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141701/1/ange201711828_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141701/2/ange201711828.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141701/3/ange201711828-sup-0001-misc_information.pd

Endocrine therapy resistant ESR1 variants revealed by genomic characterization of breast cancer derived xenografts

To characterize patient-derived xenografts (PDXs) for functional studies, we made whole-genome comparisons with originating breast cancers representative of the major intrinsic subtypes. Structural and copy number aberrations were found to be retained with high fidelity. However, at the single-nucleotide level, variable numbers of PDX-specific somatic events were documented, although they were only rarely functionally significant. Variant allele frequencies were often preserved in the PDXs, demonstrating that clonal representation can be transplantable. Estrogen-receptor-positive PDXs were associated with ESR1 ligand-binding-domain mutations, gene amplification, or an ESR1/YAP1 translocation. These events produced different endocrine-therapy-response phenotypes in human, cell line, and PDX endocrine-response studies. Hence, deeply sequenced PDX models are an important resource for the search for genome-forward treatment options and capture endocrine-drug-resistance etiologies that are not observed in standard cell lines. The originating tumor genome provides a benchmark for assessing genetic drift and clonal representation after transplantation

Endocrine-Therapy-Resistant ESR1 Variants Revealed by Genomic Characterization of Breast-Cancer-Derived Xenografts

To characterize patient-derived xenografts (PDXs) for functional studies, we made whole-genome comparisons with originating breast cancers representative of the major intrinsic subtypes. Structural and copy number aberrations were found to be retained with high fidelity. However, at the single-nucleotide level, variable numbers of PDX-specific somatic events were documented, although they were only rarely functionally significant. Variant allele frequencies were often preserved in the PDXs, demonstrating that clonal representation can be transplantable. Estrogen-receptor-positive PDXs were associated with ESR1 ligand-binding-domain mutations, gene amplification, or an ESR1/YAP1 translocation. These events produced different endocrine-therapy-response phenotypes in human, cell line, and PDX endocrine-response studies. Hence, deeply sequenced PDX models are an important resource for the search for genome-forward treatment options and capture endocrine-drug-resistance etiologies that are not observed in standard cell lines. The originating tumor genome provides a benchmark for assessing genetic drift and clonal representation after transplantation

BM-1197: a novel and specific Bcl-2/Bcl-xL inhibitor inducing complete and long-lasting tumor regression in vivo.

Bcl-2 and Bcl-xL are critical regulators of apoptosis that are overexpressed in a variety of human cancers and pharmacological inhibition of Bcl-2 and Bcl-xL represents a promising strategy for cancer treatment. Using a structure-based design approach, we have designed BM-1197 as a potent and efficacious dual inhibitor of Bcl-2 and Bcl-xL. BM-1197 binds to Bcl-2 and Bcl-xL proteins with Ki values less than 1 nM and shows >1,000-fold selectivity over Mcl-1. Mechanistic studies performed in the Mcl-1 knockout mouse embryonic fibroblast (MEF) cells revealed that BM-1197 potently disassociates the heterodimeric interactions between anti-apoptotic and pro-apoptotic Bcl-2 family proteins, concomitant with conformational changes in Bax protein, loss of mitochondrial membrane potential and subsequent cytochrome c release to the cytosol, leading to activation of the caspase cascade and apoptosis. BM-1197 exerts potent growth-inhibitory activity in 7 of 12 small cell lung cancer cell lines tested and induces mechanism-based apoptotic cell death. When intravenously administered at daily or weekly in H146 and H1963 small-cell lung cancer xenograft models, it achieves complete and long-term tumor regression. Consistent with its targeting of Bcl-xL, BM-1197 causes transit platelet reduction in mice. Collectively, our data indicate that BM-1197 is a promising dual Bcl-2/Bcl-xL inhibitor which warrants further investigation as a new anticancer drug

Cell growth inhibitory activity of BM-1197 and ABT-263 against SCLC cell lines.

<p>The concentration of drugs that inhibits 50% of cell growth (IC₅₀) compared to DMSO control after 96-h incubation with drugs was determined. The data represent means ± SD (n = 3–6).</p

BM-1197 decreases platelet count in mice.

<p>BM-1197 was administered by IV bolus injected into the tail vein. At the indicated time points the mice were euthanized and blood was drawn for complete blood count. Data are mean ± SEM (n = 3).</p