BCR-ABL Inhibitor Research Articles

Design, synthesis, and biological evaluation of trizole-based heteroaromatic derivatives as Bcr-Abl kinase inhibitors

Bcr-Abl is a key driver in the pathophysiology of CML. Broadening the chemical diversity of Bcr-Abl kinase inhibitors to overcome drug resistance is a current medical demand for CML treatment. As a continuation to our research, a series of compounds with heteroaromatics-trizole scaffold as hinge binding moiety (HBM) were developed as Bcr-Abl inhibitors based on in silico modeling analysis. Biological results indicated that these compounds exhibited a significantly enhanced inhibition against Bcr-AblWT and Bcr-AblT315I in kinases assays, along with improved anti-proliferative activities in leukemia cell assays, compared with previous disclosed compounds. In particular, compounds 9f, 28c, 31, and 44c displayed comparable even better potency with that of Imatinib in enzymatic assay and cell assays including K562 cells and adriamycin-resistant K562/A cells. Moreover, compounds 9f, 28c, and 44c exhibited potent inhibition activities against K562R cells bearing T315I mutant with IC50 of 13.35 μM, 40.14 μM, and 1.91 μM, respectively, outperforming that of Imatinib. Meanwhile, the inhibition of Bcr-Abl activity in Ba/F3 cells demonstrated that these compounds exerted effects mainly by acting on Bcr-Abl. Additionally, compounds 9f, 28c, and 44c effectively induced apoptosis, arrest the cell cycle at S or G2/M phase, and inhibited phosphorylation of Bcr-Abl and STAT5 in a dose-dependent manner. Docking studies indicated that trizole indeed retained the hydrophobic interaction of aromatic heterocycles with hinge region, and ADME prediction suggested that tested compounds had a favorable safety profile. Therefore, aromatic heterocycles incorporated with trizole could serve as a promising HBM for Bcr-Abl inhibitors with proline as fexibile linker, and compounds 9f, 28c, especially 44c could be served as a starting point for further optimization.

Research Status, Synthesis and Clinical Application of Recently Marketed and Clinical BCR-ABL Inhibitors.

Tyrosine kinases expressed by BCR-ABL fusion genes can cause changes in cell proliferation, adhesion, and survival properties, which are the main causes of chronic myelogenous leukemia (CML). Inhibiting the activity of BCR-ABL tyrosine kinase has become one of the effective methods for the treatment of chronic myelogenous leukemia. Initially, imatinib was the first small molecule of BCR-ABL tyrosine kinases inhibitors (TKIs) for the effective treatment of chronic myelogenous leukemia. Later, due to the emergence of various BCR-ABL mutations, especially T315I mutation, imatinib developed strong resistance. The second-generation kinase inhibitors dasatinib and nilotinib were able to overcome most of the mutation resistance but not T315I mutations. Therefore, in order to further overcome the problem of drug resistance, new types of KTIs such as flumatinib and radotinib have been developed, providing more options for clinical treatment. Some new drugs have entered clinical trials. In this review, two new BCRABL inhibitors (flumatinib and radotinib) and five new BCR-ABL inhibitors have been introduced into the clinical market in recent years. We reviewed their research status, synthesis methods, and clinical applications.

Abstract #1179582: A Case of Ponatinib Induced Hypothyroidism

Chronic myelogenous leukemia (CML) is a myeloproliferative neoplasm caused by abnormal fusion of genes BCR and ABL1 and unregulated growth of granulocytes. BCR-ABL1 tyrosine kinase inhibitors (TKIs) are the mainstay of treatment for CML. There is limited information regarding ponatinib, a third generation TKI, and endocrine dysfunction. This case describes a patient who developed new-onset primary hypothyroidism following initiation of ponatinib.

Bioactive Lipids as Chronic Myeloid Leukemia's Potential Biomarkers for Disease Progression and Response to Tyrosine Kinase Inhibitors.

Chronic myelogenous leukemia (CML) is a myeloproliferative neoplasm that expresses the Philadelphia chromosome and constitutively activated Bcr-Abl tyrosine kinase in hematopoietic progenitor cells. Bcr-Abl tyrosine-kinase inhibitors (TKI) do not definitively cure all CML patients. The efficacy of TKI is reduced in CML patients in the blastic phase—the most severe phase of the disease—and resistance to this drug has emerged. There is limited knowledge on the underlying mechanisms of disease progression and resistance to TKI beyond BCR-ABL1, as well as on the impact of TKI treatment and disease progression on the metabolome of CML patients. The present study reports the metabolomic profiles of CML patients at different phases of the disease treated with TKI. The plasma metabolites from CML patients were analyzed using liquid chromatography, mass spectrometry, and bioinformatics. Distinct metabolic patterns were identified for CML patients at different phases of the disease and for those who were resistant to TKI. The lipid metabolism in CML patients at advanced phases and TKI-resistant patients is reprogrammed, as detected by analysis of metabolomic data. CML patients who were responsive and resistant to TKI therapy exhibited distinct enriched pathways. In addition, ceramide levels were higher and sphingomyelin levels were lower in resistant patients compared with control and CML groups. Taken together, the results here reported established metabolic profiles of CML patients who progressed to advanced phases of the disease and failed to respond to TKI therapy as well as patients in remission. In the future, an expanded study on CML metabolomics may provide new potential prognostic markers for disease progression and response to therapy.

Cardiovascular management of patients with chronic myeloid leukemia treated with BCR-ABL tyrosine kinase inhibitors: it is time for a shared management

Chronic myeloid leukemia is a rare myeloproliferative disease, characterized by a chromosomal translocation detected in 95% of cases, defined as "Philadelphia chromosome", encoding for the BCR-ABL fusion protein with continuous activation of the tyrosine kinase domain. Over the last 20 years, treatment has been revolutionized by the use of BCR-ABL tyrosine kinase inhibitors (TKI). Imatinib is the first TKI approved with a good cardiovascular safety profile, while some second-generation (nilotinib and dasatinib) and third-generation (ponatinib) drugs, developed to overcame drug resistance, can be associated with cardiovascular adverse events. The major adverse effect of dasatinib is pulmonary hypertension, reversible after treatment discontinuation. Conversely, nilotinib or ponatinib assumption is associated with a higher incidence of ischemic events, including coronary artery disease, cerebral stroke and peripheral arterial disease. Therefore, the management of patients receiving TKI therapy should include an integrated multidisciplinary evaluation and follow-up, involving highly specialized figures such as a cardiologist, hematologist and/or oncologist and the application of dedicated pathways, in order to prevent the onset or manage cardiovascular complications associated with these drugs.

Brefeldin A Induces Apoptosis, Inhibits BCR-ABL Activation, and Triggers BCRABL Degradation in Chronic Myeloid Leukemia K562 Cells.

Chronic Myeloid Leukemia (CML) is a myeloproliferative disease caused by BCR-ABL oncoprotein. Tyrosine kinase inhibitors have been developed to inhibit the activity of BCR-ABL; however, drug resistance and side effect occur in clinic application. Therefore, it is urgent to find novel drugs for CML treatment. Under the guidance of cytotoxic activity, crude extracts of 55 fungal strains from the medicinal mangrove Acanthus ilicifolius were evaluated, and one potent cytotoxic natural compound, brefeldin A (BFA), was discovered from Penicillium sp. (HS-N-29). This study was aimed to determine the cytotoxic activity of BFA and the effect on the activation and expression of BCR-ABL in K562 cells. We evaluated cytotoxic activity by MTT assay and soft agar clone assay; apoptosis and cell cycle distribution by Muse cell analyzer. The protein level of BCR-ABL and signaling molecules was detected by western blotting, and the mRNA level of BCR-ABL was determined by RT-PCR. BFA inhibited cell proliferation, induced G2/M cell cycle arrest, and stimulated cell apoptosis in K562 cells. Importantly, for the first time, we revealed that BFA inhibited the activation of BCR-ABL and consequently inhibited the activation of its downstream signaling molecules in K562 cells. Moreover, we found BFA degraded BCR-ABL without affecting its transcription in K562 cells, and BFA-induced BCR-ABL degradation was related to caspase activation, while not to autophagy or ubiquitinated proteasome degradation pathway. Our present results indicate that BFA acts as a dual functional inhibitor and degrader of BCR-ABL, and BFA is a potential compound for chemotherapeutics to overcome CML.

Stachydrine is effective and selective against blast phase chronic myeloid leukaemia through inhibition of multiple receptor tyrosine kinases

Context Resistance to BCR-ABL tyrosine kinase inhibitor (TKI) is the cause of treatment failure in blast phase chronic myeloid leukaemia (BP-CML). Agents that act synergistically with BCR-ABL TKI are required to improve response. Objective This work investigated the effects of stachydrine in CML. Materials and methods CML cells were treated with control or stachydrine at 20, 40 and 80 µM. Proliferation and apoptosis were examined after 72 h treatment. Combination studies were performed in four groups: control, TKI, stachydrine and the combination of stachydrine and TKI. Immunoblotting analysis was performed in CML cells after 24 h treatment. Results Stachydrine inhibited K562 (IC50 61 µM), KCL22 (IC50 141 µM), LAMA84 (IC50 86 µM), Ba/F3 T315I (IC50 26 µM), Ba/F3 WT (IC50 22 µM) and KU812 (IC50 35 µM) proliferation, and induced apoptosis in these CML cell lines. Stachydrine significantly induced apoptosis, inhibited colony formation and self-renewal in BP-CML CD34+ cells. The combination index of stachydrine and TKI combination was <1. Compared to TKI alone, the combination of stachydrine and TKI significantly induced more apoptosis and decreased colony formation in BP-CML CD34+ cells. Stachydrine decreased phosphorylation levels of multiple receptor tyrosine kinases in CML cells. Discussion and conclusions Our study is the first to demonstrate (1) the anticancer activity of stachydrine on primary patient cancer cells; (2) the inhibitory effects of stachydrine on cancer stem cells; (3) the synergism between stachydrine and other anticancer drugs.

Principles of Kinase Allosteric Inhibition and Pocket Validation.

With several marketed drugs, allosteric inhibition of kinases has translated to pharmacological effects and clinical benefits comparable to those from orthosteric inhibition. However, despite much effort over more than 20 years, the number of kinase targets associated with FDA-approved allosteric drugs is limited, suggesting the challenges in identifying and validating allosteric inhibitors. Here we review the principles of allosteric inhibition, summarize the discovery of allosteric MEK1/2 and BCR-ABL1 inhibitors, and discuss the approaches to screening and demonstrating the functional activity of allosteric pocket ligands.

Mechanistic Insights Into Co-Administration of Allosteric and Orthosteric Drugs to Overcome Drug-Resistance in T315I BCR-ABL1

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm, driven by the BCR-ABL1 fusion oncoprotein. The discovery of orthosteric BCR-ABL1 tyrosine kinase inhibitors (TKIs) targeting its active ATP-binding pocket, such as first-generation Imatinib and second-generation Nilotinib (NIL), has profoundly revolutionized the therapeutic landscape of CML. However, currently targeted therapeutics still face considerable challenges with the inevitable emergence of drug-resistant mutations within BCR-ABL1. One of the most common resistant mutations in BCR-ABL1 is the T315I gatekeeper mutation, which confers resistance to most current TKIs in use. To resolve such conundrum, co-administration of orthosteric TKIs and allosteric drugs offers a novel paradigm to tackle drug resistance. Remarkably, previous studies have confirmed that the dual targeting BCR-ABL1 utilizing orthosteric TKI NIL and allosteric inhibitor ABL001 resulted in eradication of the CML xenograft tumors, exhibiting promising therapeutic potential. Previous studies have demonstrated the cooperated mechanism of two drugs. However, the conformational landscapes of synergistic effects remain unclear, hampering future efforts in optimizations and improvements. Hence, extensive large-scale molecular dynamics (MD) simulations of wide type (WT), WT-NIL, T315I, T315I-NIL, T315I-ABL001 and T315I-ABL001-NIL systems were carried out in an attempt to address such question. Simulation data revealed that the dynamic landscape of NIL-bound BCR-ABL1 was significantly reshaped upon ABL001 binding, as it shifted from an active conformation towards an inactive conformation. The community network of allosteric signaling was analyzed to elucidate the atomistic overview of allosteric regulation within BCR-ABL1. Moreover, binding free energy analysis unveiled that the affinity of NIL to BCR-ABL1 increased by the induction of ABL001, which led to its favorable binding and the release of drug resistance. The findings uncovered the in-depth structural mechanisms underpinning dual-targeting towards T315I BCR-ABL1 to overcome its drug resistance and will offer guidance for the rational design of next generations of BCR-ABL1 modulators and future combinatory therapeutic regimens.

Cardiovascular Adverse Events and Mitigation Strategies for Chronic Myeloid Leukemia Patients Receiving Tyrosine Kinase Inhibitor Therapy.

Cardiovascular (CV) risk mitigation is an important consideration in the management of chronic myeloid leukemia (CML) patients. Although BCR-ABL1 inhibition by tyrosine kinase inhibitors (TKI) has led to a significant improvement in prognosis, the majority of CML patients will require indefinite TKI therapy. Given the success of therapy, there has been a shift in focus to include CV care as part of routine patient management. To optimize outcomes, both patient-specific comorbidities and a detailed understanding of the cardiotoxicity safety profiles imparted by each TKI should be considered during agent selection. Clinicians face the challenge of early detection and management of these cardiotoxicities while balancing the risk-benefit ratios of maintaining life-saving cancer therapy. Advanced practitioners play a critical role in CML patient management that extends to the recognition and management of TKI-associated side effects. They should be cognizant of the potential for TKI-associated cardiotoxicities along with appropriate baseline risk assessments, active surveillance, and mitigation strategies as part of a collaborative team effort with cardio-oncologists.

Development of asciminib, a novel allosteric inhibitor of BCR-ABL1.

Chronic myeloid leukemia (CML) is driven by a translocation event between chromosomes 9 and 22, leading to the formation of a constitutively active BCR-ABL1 oncoprotein. Approved tyrosine kinase inhibitors (TKIs) for CML inhibit BCR-ABL1 by competitively targeting its adenosine triphosphate (ATP)-binding site, which significantly improves patient outcomes. However, resistance to and intolerance of TKIs remains a clinical challenge. Asciminib is a promising investigational agent in development that allosterically targets BCR-ABL1 in a non-ATP-competitive manner. It binds to the ABL1 myristoyl-binding pocket and is effective against most ABL1 kinase domain mutations that confer resistance to ATP-competitive TKIs, including the T315I mutation. This review discusses unmet needs in the current CML treatment landscape, reports clinical data from asciminib trials that support the use of single-agent asciminib as third-line therapy and beyond, and explores the potential benefit of asciminib in combination with approved TKIs in earlier lines.

Cardiotoxicity of Non-Anthracycline Cancer Chemotherapy Agents.

Throughout the last decades, newly developed chemotherapeutic agents and immunotherapies that target signaling pathways have provided patients with better prognoses, improved their quality of life and increased survival rates, thus converting cancer to a stable chronic disease. However, non-anthracycline cancer chemotherapy agents and immunotherapies including human epidermal growth factor receptor 2 (HER2) inhibitors, vascular endothelial growth factor (VEGF) inhibitors, Bcr-Abl tyrosine-kinase inhibitors (TKI), proteasome inhibitors, immune checkpoint inhibitors and chimeric antigen receptor T cells (CAR-T cells) may cause cardiovascular toxicity events and complications that usually interrupt the continuation of an appropriate treatment regimen, which induces life-threatening risks or leads to long-term morbidity. Heart failure, cardiac arrythmias and cardiomyopathies are the most common cardiovascular events related to cardiotoxicity due to chemotherapy. Each patient should be carefully assessed and monitored before, during and after the administration of chemotherapy, to address any predisposing risk factors and the new onset of cardiotoxicity manifestations early and treat them appropriately. The development of novel anticancer agents that cause minimal cardiovascular toxicity events or novel agents that ameliorate the adverse effects of the existing anticancer agents could drastically change the field of cardio-oncology. The aim of this narrative review is to demonstrate new knowledge regarding the screening and diagnosis of non-anthracycline-induced cardiotoxicity and to propose protective measures that could be performed in order to achieve the delivery of optimal care.

Olverembatinib: First Approval.

Olverembatinib (HQP1351) is an oral, third-generation BCR-ABL1 tyrosine kinase inhibitor (TKI) developed by Ascentage Pharma for the treatment of chronic myeloid leukaemia (CML), acute myeloid leukaemia, acute lymphoblastic leukaemia (ALL) and solid tumours, including gastrointestinal stromal tumours (GIST). Olverembatinib is an ATP binding-site inhibitor of wild type BCR-ABL1 kinase and a broad spectrum of BCR-ABL1 mutants, including mutant T315I, which confers resistance against all first- and second-generation TKIs. In November 2021, olverembatinib received its first approval in China for the treatment of adult patients with TKI-resistant chronic-phase CML (CML-CP) or accelerated-phase CML (CML-AP) harbouring the T315I mutation, as confirmed by a validated diagnostic test. Clinical studies are underway in the US for CML and precursor cell ALL, and in China for solid tumours, including GIST. This article summarizes the milestones in the development of olverembatinib leading to this first approval for the treatment of CML-CP or CML-AP.

In silico and in vitro evaluation of imatinib as an inhibitor for SARS-CoV-2

The rapid geographic expansion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the infectious agent of Coronavirus Disease 2019 (COVID-19) pandemic, poses an immediate need for potent drugs. Enveloped viruses infect the host cell by cellular membrane fusion, a crucial mechanism required for virus replication. The SARS-CoV-2 spike glycoprotein, due to its primary interaction with the human angiotensin-converting enzyme 2 (ACE2) cell-surface receptor, is considered a potential target for drug development. In this study, around 5,800 molecules were virtually screened using molecular docking. Five molecules were selected for in vitro experiments from those that reported docking scores lower than −6 kcal/mol. Imatinib, a Bcr-Abl tyrosine kinase inhibitor, showed maximum antiviral activity in Vero cells. We further investigated the interaction of imatinib, a compound under clinical trials for the treatment of COVID-19, with SARS-CoV-2 RBD, using in silico methods. Molecular dynamics simulations verified that imatinib interacts with RBD residues that are critical for ACE2 binding. This study also provides significant molecular insights on potential repurposable small-molecule drugs and chemical scaffolds for the development of novel drugs targeting the SARS-CoV-2 spike RBD. Communicated by Ramaswamy H. Sarma

Discovery of Anticancer Hybrid Molecules by Supervised Machine Learning Models and in Vitro Validation in Drug Resistant Chronic Myeloid Leukemia Cells.

The concept of hybrid drugs for targeting multiple aberrant pathways of cancer, by combining the key pharmacophores of clinically approved single-targeted drugs, has emerged as a promising approach for overcoming drug-resistance. Here, we report the design of unique hybrid molecules by combining the two pharmacophores of clinically approved BCR-ABL inhibitor (ponatinib) and HDAC inhibitor (vorinostat) and results of in vitro studies in drug-resistant CML cells. Robust 2D-QSAR and 3D-pharmacophore machine learning supervised models were developed for virtual screening of the hybrid molecules based on their predicted BCR-ABL and HDAC inhibitory activity. The developed 2D-QSAR model showed five information rich molecular descriptors while the 3D-pharmacophore model of BCR-ABL showed five different chemical features (hydrogen bond acceptor, donor, hydrophobic group, positive ion group, and aromatic rings) and the HDAC model showed four different chemical features (hydrogen bond acceptor, donor, positive ion group, and aromatic rings) for potent BCR-ABL and HDAC inhibition. Virtual screening of the 16 designed hybrid molecules identified FP7 and FP10 with better potential of inhibitory activity. FP7 was the most effective molecule with predicted IC50 using the BCR-ABL based 2D-QSAR model of 0.005 μM and that of the HDAC model of 0.153 μM, and that using the BCR-ABL based 3D-pharmacophore model was 0.02 μM and that with HDAC model was 0.014 μM. In vitro study (dose-response relationship) of FP7 in wild type and imatinib-resistant CML cell lines harboring Thr315Ile or Tyr253His mutations showed growth inhibitory IC50 values of 0.000 16, 0.0039, and 0.01 μM, respectively. This molecule also showed better biocompatibility when tested in whole blood and in PBMCs as compared to ponatinib or vorinostat.

Drugging the undruggable: Ross Cagan interviews Kevan Shokat.

Drugging the undruggable: Ross Cagan interviews Kevan Shokat.

Eliminating chronic myeloid leukemia stem cells by IRAK1/4 inhibitors

Leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) are quiescent, insensitive to BCR-ABL1 tyrosine kinase inhibitors (TKIs) and responsible for CML relapse. Therefore, eradicating quiescent CML LSCs is a major goal in CML therapy. Here, using a G0 marker (G0M), we narrow down CML LSCs as G0M- and CD27- double positive cells among the conventional CML LSCs. Whole transcriptome analysis reveals NF-κB activation via inflammatory signals in imatinib-insensitive quiescent CML LSCs. Blocking NF-κB signals by inhibitors of interleukin-1 receptor-associated kinase 1/4 (IRAK1/4 inhibitors) together with imatinib eliminates mouse and human CML LSCs. Intriguingly, IRAK1/4 inhibitors attenuate PD-L1 expression on CML LSCs, and blocking PD-L1 together with imatinib also effectively eliminates CML LSCs in the presence of T cell immunity. Thus, IRAK1/4 inhibitors can eliminate CML LSCs through inhibiting NF-κB activity and reducing PD-L1 expression. Collectively, the combination of TKIs and IRAK1/4 inhibitors is an attractive strategy to achieve a radical cure of CML.

Comparison of Dasatinib- and Imatinib-Related Cardiotoxic Adverse Events in Japanese Patients With Chronic Myeloid Leukemia and Gastrointestinal Stromal Tumor.

Background: Despite the beneficial effects of BCR-ABL1 tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML), they may also cause adverse events (AEs), especially cardiovascular toxicity. The incidence of TKI-induced AEs may vary among ethnic groups, and there is little specific information for Japanese patients. Methods and Results: Sixty-nine consecutive patients who were started on treatment with dasatinib (n=25) or imatinib (n=44) for CML or gastrointestinal stromal tumor (GIST) between December 2008 and December 2019 were retrospectively recruited to the study. We determined the prevalence of AEs through October 2020 and compared the incidence of AEs between the 2 drugs. Baseline characteristics were comparable between the 2 groups. However, compared with the imatinib-treated group, the dasatinib-treated group had a higher incidence of congestive heart failure (CHF; 20.0% vs. 2.3%; P=0.04), pleural effusion (48% vs. 20.5%; P=0.03), pericardial effusion (24% vs. 4.6%; P=0.02), QT prolongation (4 vs. 0 patients; P=0.02), and pulmonary hypertension (3 vs. 0 patients; P=0.04). In the dasatinib-treated group, CHF tended to be associated with tricuspid valve regurgitation pressure gradient, and pleural effusion was observed in all patients. All-cause mortality and other cardiovascular events did not differ significantly between the 2 groups. Conclusions: Cardiotoxic AEs occurred more frequently in Japanese patients with CML and GIST treated with dasatinib than imatinib.

Diffuse plate-like sheets of desquamation

Diffuse plate-like sheets of desquamation

Toxicity assessment of tyrosine kinase inhibitors using human-induced pluripotent stem cell-derived cardiomyocytes

BCR-ABL tyrosine kinase inhibitors (TKIs) have contributed to the improvement of the survival of patients with chronic myelogenous leukemia (CML). Growing evidence suggests that cancer therapy-related cardiac dysfunction has become important as the most undesirable side effect of chemotherapy. For example, one of BCR-ABL TKIs, nilotinib, has been reported to have a risk of QT prolongation associated with Torsades des Pointes and cardiac failure. We have previously reported that nilotinib causes QT prolongation and early afterdepolarization (EAD) using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). In this study, we evaluated the effect of BCR-ABL TKIs on contractility using hiPSC-CMs.