Synergistic activity of BET inhibitor BI 894999 with PLK inhibitor volasertib in AML in vitro and in vivo
Ontology highlight
ABSTRACT: Interactions between a new potent Bromodomain and extraterminal domain (BET) inhibitor BI 894999 and the polo-like kinase (PLK) inhibitor volasertib were studied in acute myeloid leukemia cell lines in vitro and in vivo. We provide data for the distinct mechanisms of action of these two compounds with a potential utility in AML based on gene expression, cell cycle profile and modulation of PD biomarkers such as MYC and HEXIM1. In contrast to BI 894999, volasertib treatment neither affects MYC nor HEXIM1 expression, but augments and prolongs the decrease of MYC expression caused by BI 894999 treatment. In vitro combination of both compounds leads to a decrease in S-Phase and to increased apoptosis. In vitro scheduling experiments guided in vivo experiments in disseminated AML mouse models. Co-administration of BI 894999 and volasertib dramatically reduces tumor burden accompanied by long-term survival of tumor-bearing mice and eradication of AML cells in mouse bone marrow. Together, these preclinical findings provide evidence for the strong synergistic effect of BI 894999 and volasertib, warranting future clinical studies in patients with AML to investigate this paradigm.
Project description:MLL rearranged (MLLr) leukemia is in general characterized by a poor prognosis. Depending on the cell of origin, it can differ in the aggressiveness and the therapy response. For instance, in adults, volasertib blocking Polo-like-Kinase 1 (PLK-1), was well-tolerated, but only with limited success. On the other site, PLK-1 characterizes an infant MLLr signature indicating a potential specific sensitivity. By using our CRISPR/Cas9 MLLr model in hematopoietic stem and progenitor cells (HSPCs), derived from both human cord blood (huCB) and bone marrow (huBM), mimicking exactly the infant and adult patient diseases, we were able to shed light on this phenomenon. PLK-1 was significantly increased in our huCB compared to huBM model and healthy HPSCs, that was underpinned by analyzing infant and adult MLLr leukemia patients. Importantly, the expression height correlated with a functional response. Volasertib induced a significant dose-dependent decrease of proliferation and cell cycle arrest most pronounced in the infant model. Mechanistically, upon volasertib treatment, we uncovered a negative feedback only in the huBM model by compensatory upregulation of PLK-1. Our study emphasizes the importance of the cell of origin in leukemogenesis and provides the rationale to further evaluate volasertib as new therapeutic strategy in infant MLLr leukemia.
Project description:In this study we aimed to identify off-targets of polo-like kinase 1 (Plk1) small molecule inhibitor volasertib. Plk1 is an important cell cycle kinase and an attractive target for anticancer treatment. Volasertib is ATP-competitive small molecules that may also block the ATP-pocket of other proteins. Despite the fatal infections and negative survival in a phase III trial on volasertib in acute myeloid leukemia volasertib has been a promising treatment option in children with rhabdomyosarcoma. Therefore, there is a need to understand the nature of adverse effects that possibly originate from the off-target proteins. We used thermal proteome profiling (TPP) to identify proteins that have a change in the thermal stability after treatment with volasertib. The temperature of aggregation of several proteins involved in prostaglandin and phosphatidyl-inositol phosphate metabolism increased after treatment with volasertib. PIP4K2A and ZADH2 were stabilized both by treatment in living cells and cell lysate. Functional disruption of these proteins affects the immune response and fatty acid metabolism. In addition, volasertib was found to affect transcriptional coactivators, normal and alternative RNA splicing regulators and proteins involved in the intracellular transport regulation. Our data suggests that the identified proteins may contribute more to the understanding of anti-tumor effect of volasertib.
Project description:In this study we aimed to identify off-targets of polo-like kinase 1 (Plk1) small molecule inhibitor volasertib. Plk1 is an important cell cycle kinase and an attractive target for anticancer treatment. Volasertib is ATP-competitive small molecules that may also block the ATP-pocket of other proteins. Despite the fatal infections and negative survival in a phase III trial on volasertib in acute myeloid leukemia volasertib has been a promising treatment option in children with rhabdomyosarcoma. Therefore, there is a need to understand the nature of adverse effects that possibly originate from the off-target proteins. We used thermal proteome profiling (TPP) to identify proteins that have a change in the thermal stability after treatment with volasertib. The temperature of aggregation of several proteins involved in prostaglandin and phosphatidyl-inositol phosphate metabolism increased after treatment with volasertib. PIP4K2A and ZADH2 were stabilized both by treatment in living cells and cell lysate. Functional disruption of these proteins affects the immune response and fatty acid metabolism. In addition, volasertib was found to affect transcriptional coactivators, normal and alternative RNA splicing regulators and proteins involved in the intracellular transport regulation. Our data suggests that the identified proteins may contribute more to the understanding of anti-tumor effect of volasertib.
Project description:Germline, mono-allelic mutations in RUNX1 cause familial platelet disorder (RUNX1-FPD) that evolves into myeloid malignancy (FPD-MM): MDS or AML. FPD-MM commonly harbors co-mutations in the second RUNX1 allele and/or other epigenetic regulators. Here we utilized patient-derived (PD) FPD-MM cells and established the first FPD-MM AML cell line (GMR-AML1). GMR-AML1 cells exhibited active super-enhancers of MYB, MYC, BCL2 and CDK6, augmented expressions of c-Myc, c-Myb, EVI1 and PLK1 and surface markers of AML stem cells. In longitudinally studied bone marrow cells from a patient at FPD-MM vs RUNX1-FPD state, we confirmed increased chromatin accessibility and mRNA expressions of MYB, MECOM and BCL2 in FPD-MM cells. GMR-AML1 and PD FPD-MM cells were sensitive to homoharringtonine (HHT or omacetaxine) or mebendazole-induced lethality, associated with repression of c-Myc, EVI1, PLK1, CDK6 and MCL1. Co-treatment with MB and the PLK1 inhibitor volasertib exerted synergistic in vitro lethality in GMR-AML1 cells. In luciferase-expressing GMR-AML1 xenograft model, MB, omacetaxine or volasertib monotherapy, or co-treatment with MB and volasertib, significantly reduced AML burden and improved survival in the immune-depleted mice. These findings highlight the molecular features of FPD-MM progression and demonstrate HHT, MB and/or volasertib as effective agents against cellular models of FPD-MM.
Project description:Germline, mono-allelic mutations in RUNX1 cause familial platelet disorder (RUNX1-FPD) that evolves into myeloid malignancy (FPD-MM): MDS or AML. FPD-MM commonly harbors co-mutations in the second RUNX1 allele and/or other epigenetic regulators. Here we utilized patient-derived (PD) FPD-MM cells and established the first FPD-MM AML cell line (GMR-AML1). GMR-AML1 cells exhibited active super-enhancers of MYB, MYC, BCL2 and CDK6, augmented expressions of c-Myc, c-Myb, EVI1 and PLK1 and surface markers of AML stem cells. In longitudinally studied bone marrow cells from a patient at FPD-MM vs RUNX1-FPD state, we confirmed increased chromatin accessibility and mRNA expressions of MYB, MECOM and BCL2 in FPD-MM cells. GMR-AML1 and PD FPD-MM cells were sensitive to homoharringtonine (HHT or omacetaxine) or mebendazole-induced lethality, associated with repression of c-Myc, EVI1, PLK1, CDK6 and MCL1. Co-treatment with MB and the PLK1 inhibitor volasertib exerted synergistic in vitro lethality in GMR-AML1 cells. In luciferase-expressing GMR-AML1 xenograft model, MB, omacetaxine or volasertib monotherapy, or co-treatment with MB and volasertib, significantly reduced AML burden and improved survival in the immune-depleted mice. These findings highlight the molecular features of FPD-MM progression and demonstrate HHT, MB and/or volasertib as effective agents against cellular models of FPD-MM.
Project description:Germline, mono-allelic mutations in RUNX1 cause familial platelet disorder (RUNX1-FPD) that evolves into myeloid malignancy (FPD-MM): MDS or AML. FPD-MM commonly harbors co-mutations in the second RUNX1 allele and/or other epigenetic regulators. Here we utilized patient-derived (PD) FPD-MM cells and established the first FPD-MM AML cell line (GMR-AML1). GMR-AML1 cells exhibited active super-enhancers of MYB, MYC, BCL2 and CDK6, augmented expressions of c-Myc, c-Myb, EVI1 and PLK1 and surface markers of AML stem cells. In longitudinally studied bone marrow cells from a patient at FPD-MM vs RUNX1-FPD state, we confirmed increased chromatin accessibility and mRNA expressions of MYB, MECOM and BCL2 in FPD-MM cells. GMR-AML1 and PD FPD-MM cells were sensitive to homoharringtonine (HHT or omacetaxine) or mebendazole-induced lethality, associated with repression of c-Myc, EVI1, PLK1, CDK6 and MCL1. Co-treatment with MB and the PLK1 inhibitor volasertib exerted synergistic in vitro lethality in GMR-AML1 cells. In luciferase-expressing GMR-AML1 xenograft model, MB, omacetaxine or volasertib monotherapy, or co-treatment with MB and volasertib, significantly reduced AML burden and improved survival in the immune-depleted mice. These findings highlight the molecular features of FPD-MM progression and demonstrate HHT, MB and/or volasertib as effective agents against cellular models of FPD-MM.
Project description:Germline, mono-allelic mutations in RUNX1 cause familial platelet disorder (RUNX1-FPD) that evolves into myeloid malignancy (FPD-MM): MDS or AML. FPD-MM commonly harbors co-mutations in the second RUNX1 allele and/or other epigenetic regulators. Here we utilized patient-derived (PD) FPD-MM cells and established the first FPD-MM AML cell line (GMR-AML1). GMR-AML1 cells exhibited active super-enhancers of MYB, MYC, BCL2 and CDK6, augmented expressions of c-Myc, c-Myb, EVI1 and PLK1 and surface markers of AML stem cells. In longitudinally studied bone marrow cells from a patient at FPD-MM vs RUNX1-FPD state, we confirmed increased chromatin accessibility and mRNA expressions of MYB, MECOM and BCL2 in FPD-MM cells. GMR-AML1 and PD FPD-MM cells were sensitive to homoharringtonine (HHT or omacetaxine) or mebendazole-induced lethality, associated with repression of c-Myc, EVI1, PLK1, CDK6 and MCL1. Co-treatment with MB and the PLK1 inhibitor volasertib exerted synergistic in vitro lethality in GMR-AML1 cells. In luciferase-expressing GMR-AML1 xenograft model, MB, omacetaxine or volasertib monotherapy, or co-treatment with MB and volasertib, significantly reduced AML burden and improved survival in the immune-depleted mice. These findings highlight the molecular features of FPD-MM progression and demonstrate HHT, MB and/or volasertib as effective agents against cellular models of FPD-MM.
Project description:The Fanconi anemia (FA) pathway is a network of proteins critical to the preservation of genomic integrity and the prevention of cancer. FA proteins safeguard the genome by regulating the cell cycle and facilitating error-free repair of DNA damage. Bi-allelic mutation of genes encoding FA pathway proteins causes the cancer predisposition syndrome Fanconi anemia (FA), which is associated with a high incidence of acute myeloid leukemia (AML). Individuals with mono-allelic mutation of a subset FA genes do not develop FA but suffer increased lifetime risk of solid and hematological malignancies. Within the general population, approximately 14% of sporadic AMLs harbor damaging mutations within the FA pathway. Our previous work demonstrated that inhibition of the mitotic kinase PLK1 induced synthetic lethality in cells deficient for FANCA, the gene most frequently lost in FA. This finding corroborates work from others that have identified synthetic lethal interactions between PLK1 and additional FA genes (FANCG, BRCA1, and BRCA2). Together, these findings suggest that FA pathway mutations may serve as biomarkers for sensitivity to PLK1 inhibitors, which have demonstrated therapeutic efficacy in an undefined subset of AML patients. Here, THP1 AML cells were generated with shControl or shFANCA and treated with 10nM volasertib for 24 h prior to kinome profiling.
Project description:The Fanconi anemia (FA) pathway is a network of proteins critical to the preservation of genomic integrity and the prevention of cancer. FA proteins safeguard the genome by regulating the cell cycle and facilitating error-free repair of DNA damage. Bi-allelic mutation of genes encoding FA pathway proteins causes the cancer predisposition syndrome Fanconi anemia (FA), which is associated with a high incidence of acute myeloid leukemia (AML). Individuals with mono-allelic mutation of a subset FA genes do not develop FA but suffer increased lifetime risk of solid and hematological malignancies. Within the general population, approximately 14% of sporadic AMLs harbor damaging mutations within the FA pathway. Our previous work demonstrated that inhibition of the mitotic kinase PLK1 induced synthetic lethality in cells deficient for FANCA, the gene most frequently lost in FA. This finding corroborates work from others that have identified synthetic lethal interactions between PLK1 and additional FA genes (FANCG, BRCA1, and BRCA2). Together, these findings suggest that FA pathway mutations may serve as biomarkers for sensitivity to PLK1 inhibitors, which have demonstrated therapeutic efficacy in an undefined subset of AML patients. Here, HL60 AML cells were generated with shControl or shFANCA and treated with 10nM volasertib for 24 h prior to kinome profiling.
Project description:Bromodomain and extra-terminal (BET) protein inhibitors have been reported as treatment options for acute myeloid leukemia (AML) in preclinical models and are currently being evaluated in clinical trials. This work presents a novel potent and selective BET inhibitor (BI 894999), which has recently entered clinical trials (NCT02516553). In preclinical studies, this compound is highly active in AML cell lines, primary patient samples, and xenografts. HEXIM1 is described as an excellent pharmacodynamic biomarker for target engagement in tumors as well as in blood. Mechanistic studies show that BI 894999 targets super-enhancer-regulated oncogenes and other lineage-specific factors, which are involved in the maintenance of the disease state. BI 894999 is active as monotherapy in AML xenografts, and in addition leads to strongly enhanced antitumor effects in combination with CDK9 inhibitors. This treatment combination results in a marked decrease of global p-Ser2 RNA polymerase II levels and leads to rapid induction of apoptosis in vitro and in vivo. Together, these data provide a strong rationale for the clinical evaluation of BI 894999 in AML.