abt-199 and Leukemia--Myeloid

Execution of the intrinsic apoptotic pathway is controlled by the BCL-2 proteins at the level of the mitochondrial outer membrane (MOM). This family of proteins consists of prosurvival (e.g., BCL-2, MCL-1) and proapoptotic (e.g., BIM, BAD, HRK) members, the functional balance of which dictates the activation of BAX and BAK. Once activated, BAX/BAK form pores in the MOM, resulting in cytochrome c release from the mitochondrial intermembrane space, leading to apoptosome formation, caspase activation, and cleavage of intracellular targets. This pathway is induced by cellular stress including DNA damage, cytokine and growth factor withdrawal, and chemotherapy/drug treatment. A well-documented defense of leukemia cells is to shift the balance of the BCL-2 family in favor of the prosurvival proteins to protect against such intra- and extracellular stimuli. Small molecule inhibitors targeting the prosurvival proteins, named 'BH3 mimetics', have come to the fore in recent years to treat hematological malignancies, both as single agents and in combination with standard-of-care therapies. The most significant example of these is the BCL-2-specific inhibitor venetoclax, given in combination with standard-of-care therapies with great success in AML in clinical trials. As the number and variety of available BH3 mimetics increases, and investigations into applying these novel inhibitors to treat myeloid leukemias continue apace the need to evaluate where we currently stand in this rapidly expanding field is clear.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Drug Design; Humans; Leukemia, Myeloid; Molecular Mimicry; Molecular Targeted Therapy; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Sulfonamides

Acute myeloid leukemia (AML) is a heterogenous hematopoietic neoplasm with various genetic abnormalities in myeloid stem cells leading to differentiation arrest and accumulation of leukemic cells in bone marrow (BM). The multiple genetic alterations identified in leukemic cells at diagnosis are the mainstay of World Health Organization classification for AML and have important prognostic implications. Recently, understanding of heterogeneous and complicated molecular abnormalities of the disease could lead to the development of novel targeted therapeutic agents. In the past years, gemtuzumab ozogamicin, BCL-2 inhibitors (venetovlax), IDH 1/2 inhibitors (ivosidenib and enasidenib) FLT3 inhibitors (midostaurin, gilteritinib, and enasidenib), and hedgehog signaling pathway inhibitors (gladegib) have received US Food and Drug Administration (FDA) approval for the treatment of AML. Especially, AML patients with elderly age and/or significant comorbidities are not currently suitable for intensive chemotherapy. Thus, novel therapeutic planning including the abovementioned target therapies could lead to improve clinical outcomes in the patients. In the review, we will present various important and frequent molecular abnormalities of AML and introduce the targeted agents of AML that received FDA approval based on the previous studies.

Topics: Acute Disease; Antineoplastic Agents; Bridged Bicyclo Compounds, Heterocyclic; Cell Proliferation; Humans; Leukemia, Myeloid; Molecular Targeted Therapy; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Sulfonamides; United States; United States Food and Drug Administration

Topics: Antineoplastic Combined Chemotherapy Protocols; Blast Crisis; Bridged Bicyclo Compounds, Heterocyclic; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid; Leukemia, Myeloid, Acute

The BCL2 inhibitor, venetoclax, has transformed clinical care in acute myeloid leukemia (AML). However, subsets of patients do not respond or eventually acquire resistance. Venetoclax-based regimens can lead to considerable marrow suppression in some patients. Bromodomain and extraterminal inhibitors (BETi) are potential treatments for AML, as regulators of critical AML oncogenes. We tested the efficacy of novel BET inhibitor INCB054329, and its synergy with venetoclax to reduce AML without induction of hematopoietic toxicity.. INCB054329 efficacy was assessed by changes in cell cycle and apoptosis in treated AML cell lines.. INCB054329 induced dose-dependent apoptosis and quiescence in AML cell lines. PRO-seq analysis evaluated the effects of INCB054329 on transcription and confirmed reduced transcriptional elongation of key oncogenes,. Our findings suggest low dose combinations of venetoclax and BETi may be more efficacious for patients with AML than either monotherapy, potentially providing a longer, more tolerable dosing regimen.

Topics: Acute Disease; Animals; Antineoplastic Agents; Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Synergism; Female; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; K562 Cells; Leukemia, Myeloid; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Organic Chemicals; Proteins; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Suppression of apoptosis by expression of antiapoptotic BCL2 family members is a hallmark of acute myeloblastic leukemia (AML). Induced myeloid leukemia cell differentiation protein (MCL1), an antiapoptotic BCL2 family member, is commonly upregulated in AML cells and is often a primary mode of resistance to treatment with the BCL2 inhibitor venetoclax. Here, we describe VU661013, a novel, potent, selective MCL1 inhibitor that destabilizes BIM/MCL1 association, leads to apoptosis in AML, and is active in venetoclax-resistant cells and patient-derived xenografts. In addition, VU661013 was safely combined with venetoclax for synergy in murine models of AML. Importantly, BH3 profiling of patient samples and drug-sensitivity testing

Topics: Acute Disease; Animals; Antineoplastic Agents; Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Drug Resistance, Neoplasm; Drug Synergism; HL-60 Cells; Humans; Indoles; K562 Cells; Leukemia, Myeloid; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Pyrazines; Pyrazoles; Sulfonamides; THP-1 Cells; U937 Cells; Xenograft Model Antitumor Assays

Direct co-operation between sensitiser molecules BAD and NOXA in mediating apoptosis suggests that therapeutic agents which sensitise to BAD may complement agents which sensitise to NOXA. Dynamic BH3 profiling is a novel methodology that we have applied to the measurement of complementarity between sensitiser BH3 peptide mimetics and therapeutic agents. Using dynamic BH3 profiling, we show that the agent TG02, which downregulates MCL-1, sensitises to the BCL-2-inhibitory BAD-BH3 peptide, whereas the BCL-2 antagonist ABT-199 sensitises to MCL-1 inhibitory NOXA-BH3 peptide in acute myeloid leukaemia (AML) cells. At the concentrations used, the peptides did not trigger mitochondrial outer membrane permeabilisation in their own right, but primed cells to release Cytochrome C in the presence of an appropriate trigger of a complementary pathway. In KG-1a cells TG02 and ABT-199 synergised to induce apoptosis. In heterogeneous AML patient samples we noted a range of sensitivities to the two agents. Although some individual samples markedly favoured one agent or the other, in the group as a whole the combination of TG02 + ABT-199 was significantly more cytotoxic than either agent individually. We conclude that dynamic NOXA and BAD BH3 profiling is a sensitive methodology for investigating molecular pathways of drug action and complementary mechanisms of chemoresponsiveness.

Topics: Acute Disease; Antineoplastic Agents; Apoptosis; Biomimetic Materials; Blotting, Western; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cyclin D1; Cytochromes c; Drug Synergism; Gene Expression Regulation, Leukemic; Heterocyclic Compounds, 4 or More Rings; Humans; Leukemia, Myeloid; Myeloid Cell Leukemia Sequence 1 Protein; Peptide Fragments; Proto-Oncogene Proteins; Reverse Transcriptase Polymerase Chain Reaction; Sulfonamides

Topics: Antineoplastic Agents; Azacitidine; Biphenyl Compounds; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Humans; Leukemia, Myeloid; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides