Design, in silico Evaluation, and Determination of Antitumor Activity of Potential Inhibitors Against Protein Kinases: Application to BCR-ABL Tyrosine Kinase.

Despite significant progress made over the past two decades in the treatment of chronic myeloid leukemia (CML), there is still an unmet need for effective and safe agents to treat patients with resistance and intolerance to the drugs used in clinic. In this work, we designed 2-arylaminopyrimidine amides of isoxazole-3-carboxylic acid, assessed in silico their inhibitory potential against Bcr-Abl tyrosine kinase, and determined their antitumor activity in K562 (CML), HL-60 (acute promyelocytic leukemia), and HeLa (cervical cancer) cells. Based on the analysis of computational and experimental data, three compounds with the antitumor activity against K562 and HL-60 cells were identified. The lead compound efficiently suppressed the growth of these cells, as evidenced by the low IC50 values of 2.8 ± 0.8 µM (K562) and 3.5 ± 0.2 µM (HL-60). The obtained compounds represent promising basic structures for the design of novel, effective, and safe anticancer drugs able to inhibit the catalytic activity of Bcr-Abl kinase by blocking the ATP-binding site of the enzyme.

Rash with different types of BCR-ABL inhibitors in chronic myelogenous leukemia: a systematic review and meta-analysis.

Objective: A meta-analysis was conducted to systematically review the risks of all-grade as well as high-grade rash in chronic myelogenous leukemia (CML) patients using different types of BCR-ABL inhibitors. Methods: Literature published between 2000 and April 2022 were searched using PubMed, Cochrane Library, Embase and ClinicalTrials.gov. Results: A total of 12 studies were included for meta-analysis. The results showed that the incidence of all-grade or high-grade rash associated with new-generation BCR-ABL inhibitors had no significant difference compared with a standard dose of imatinib. Subgroup analysis suggested that, compared with imatinib, the incidence of all grades of rash was higher in the nilotinib, bosutinib and ponatinib groups. Conclusion: For CML patients treated with nilotinib, bosutinib and ponatinib, the occurrence of skin toxicity should not be ignored.

New 2,6,9-trisubstituted purine derivatives as Bcr-Abl and Btk inhibitors and as promising agents against leukemia.

Bcr-Abl and Btk kinases are among the targets that have been considered for the treatment of leukemia. Therefore, several strategies have focused on the use of inhibitors as chemotherapeutic tools to treat these types of leukemia, such as imatinib (for Bcr-Abl) or ibrutinib (for Btk). However, the efficacy of these drugs has been reduced due to resistance mechanisms, which have motivated the development of new and more effective compounds. In this study, we designed, synthesized and evaluated 2,6,9-trisubstituted purine derivatives as novel Bcr-Abl and Btk inhibitors. We identified 5c and 5d as potent inhibitors of both kinases (IC50 values of 40 nM and 0.58/0.66 µM for Abl and Btk, respectively). From docking and QSAR analyses, we concluded that fluorination of the arylpiperazine system is detrimental to the activity against two kinases, and we also validated our hypothesis that the substitution on the 6-phenylamino ring is important for the inhibition of both kinases. In addition, our studies indicated that most compounds could suppress the proliferation of leukemia and lymphoma cells (HL60, MV4-11, CEM, K562 and Ramos cells) at low micromolar concentrations in vitro. Finally, we preliminarily demonstrated that 5c inhibited the downstream signaling of both kinases in the respective cell models. Therefore, 5c or 5d possessed potency to be further optimized as anti-leukemia drugs by simultaneously inhibiting the Bcr-Abl and Btk kinases.

Design, synthesis, and biological activity of 4-(imidazo[1,2-b]pyridazin-3-yl)-1H-pyrazol-1-yl-phenylbenzamide derivatives as BCR-ABL kinase inhibitors.

A series of 4-((pyrazolo[1,5-a]pyrimidin-6-yl)-1H-pyrazol-1-yl)phenyl-3-benzamide derivatives and 4-((imidazo[1,2-b]pyridazin-3-yl)-1H-pyrazol-1-yl-)phenyl-3-benzamide derivatives were designed, synthesized as new BCR-ABL tyrosine kinase inhibitors by using combinational strategies of scaffold hopping and conformational constraint. These new compounds were screened for BCR-ABL1 kinase inhibitory activity, and most of them appeared good inhibitory activity against BCR-ABL1 kinase. One of the most potent compounds 16a strongly suppressed BCR-ABL1 kinase with IC50 value of 8.5nM. The tested compounds 16a and 16i showed strong inhibitory activities against K562 with IC50 value of less than 2nM. Molecular docking studies indicated that these compounds fitted well with the active site of BCR-ABL1 protein. The results showed these inhibitors may serve as lead compounds for further developing new drugs targeted BCR-ABL kinase.

Expanding the structural diversity of Bcr-Abl inhibitors: Hybrid molecules based on GNF-2 and Imatinib.

In order to expand the structural diversity of Bcr-Abl inhibitors, twenty hybrids (series E and P) have been synthesized and characterized based on Imatinib and GNF-2. Their biological activities were evaluated in vitro against human leukemia cells. Most compounds exhibited potent antiproliferative activity against K562 cells, especially for compounds E4, E5 and E7. Furthermore, these new hybrids were also screened for Abl kinase inhibitory activity, and some of them inhibited Abl kinase with low micromolar IC50 values. In particular, compound P3 displayed the most potent activity with IC50 value of 0.017 µM comparable with that of Imatinib. Molecular docking studies indicated that these novel hybrids fitted well with the active site of Bcr-Abl. These results suggested the great potential of these compounds as novel Bcr-Abl inhibitors.

Asciminib, a novel allosteric inhibitor of BCR-ABL1, shows synergistic effects when used in combination with imatinib with or without drug resistance.

In the treatment of chronic myeloid leukemia (CML), resistance to BCR-ABL inhibitors makes it difficult to continue treatment and is directly related to life expectancy. Therefore, asciminib was introduced to the market as a useful drug for overcoming drug resistance. While combining molecular targeted drugs is useful to avoid drug resistance, the new BCR-ABL inhibitor asciminib and conventional BCR-ABL inhibitors should be used as monotherapy in principle. Therefore, we investigated the synergistic effect and mechanism of the combination of asciminib and imatinib. We generated imatinib-resistant cells using the human CML cell line K562, examined the effects of imatinib and asciminib exposure on cell survival using the WST-8 assay, and comprehensively analyzed genetic variation related to drug resistance using RNA-seq and real-time PCR. A synergistic effect was observed when imatinib and asciminib were combined with or without imatinib resistance. Three genes, GRRP1, ESPN, and NOXA1, were extracted as the sites of action of asciminib. Asciminib in combination with BCR-ABL inhibitors may improve the therapeutic efficacy of conventional BCR-ABL inhibitors and prevent the development of resistance. Its dosage may be effective even at minimal doses that do not cause side effects. Further verification of this mechanism of action is needed. Additionally, cross-resistance between BCR-ABL inhibitors and asciminib may occur, which needs to be clarified through further validation as soon as possible.

New Inhibitors of Bcr-Abl Based on 2,6,9-Trisubstituted Purine Scaffold Elicit Cytotoxicity in Chronic Myeloid Leukemia-Derived Cell Lines Sensitive and Resistant to TKIs.

Bcr-Abl is an oncoprotein with aberrant tyrosine kinase activity involved in the progression of chronic myeloid leukemia (CML) and has been targeted by inhibitors such as imatinib and nilotinib. However, despite their efficacy in the treatment of CML, a mechanism of resistance to these drugs associated with mutations in the kinase region has emerged. Therefore, in this work, we report the synthesis of 14 new 2,6,9-trisubstituted purines designed from our previous Bcr-Abl inhibitors. Here, we highlight 11b, which showed higher potency against Bcr-Abl (IC50 = 0.015 µM) than imatinib and nilotinib and exerted the most potent antiproliferative properties on three CML cells harboring the Bcr-Abl rearrangement (GI50 = 0.7-1.3 µM). In addition, these purines were able to inhibit the growth of KCL22 cell lines expressing Bcr-AblT315I, Bcr-AblE255K, and Bcr-AblY253H point mutants in micromolar concentrations. Imatinib and nilotinib were ineffective in inhibiting the growth of KCL22 cells expressing Bcr-AblT315I (GI50 > 20 µM) compared to 11b-f (GI50 = 6.4-11.5 µM). Molecular docking studies explained the structure-activity relationship of these purines in Bcr-AblWT and Bcr-AblT315I. Finally, cell cycle cytometry assays and immunodetection showed that 11b arrested the cells in G1 phase, and that 11b downregulated the protein levels downstream of Bcr-Abl in these cells.

Synthesis, molecular modeling, and biological evaluation of novel imatinib derivatives as anticancer agents.

Different derivatives of imatinib were synthesized by a 3-step reaction method. The structures of the new compounds were characterized by spectroscopic methods. For quantitative evaluation of the biological activity of the compounds, MTT assays were performed, where four BCR-ABL negative leukemic cell lines (Jurkat, Reh, Nalm-6 and Molt-4), one BCR-ABL positive cell line (K562), and one non-leukemic cell line (Hek293T) were incubated with various concentrations of the derivatives. Although imatinib was specifically designed for the BCR-ABL protein, our results showed that it was also effective on BCR-ABL negative cell lines except for Reh cell line. Compound 9 showed lowest IC50 values against Nalm-6 cells as 1.639 µM, also the values of Compound 10 for each cell were very close to imatinib. Molecular docking simulations suggest that except for compound 6, the compounds prefer a DFG-out conformation of the ABL kinase domain. Among them, compound 10 has the highest affinity for ABL kinase domain that is close to the affinity of imatinib. The common rings between compound 10 and imatinib adopt exactly the same conformation and same type of interactions in the ATP binding site with the ABL kinase domain.

Pharmacovigilance evaluation of the relationship between impaired glucose metabolism and BCR-ABL inhibitor use by using an adverse drug event reporting database.

Breakpoint cluster region-Abelson murine leukemia (BCR-ABL) inhibitors markedly improve the prognosis of chronic myeloid leukemia. However, high treatment adherence is necessary for successful treatment with BCR-ABL inhibitors. Therefore, an adequate understanding of the adverse event profiles of BCR-ABL inhibitors is essential. Although many adverse events are observed in trials, an accurate identification of adverse events based only on clinical trial results is difficult because of strict entry criteria or limited follow-up durations. In particular, BCR-ABL inhibitor-induced impaired glucose metabolism remains controversial. Pharmacovigilance evaluations using spontaneous reporting systems are useful for analyzing drug-related adverse events in clinical settings. Therefore, we conducted signal detection analyses for BCR-ABL inhibitor-induced impaired glucose metabolism by using the FDA Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) database. Signals for an increased reporting rate of impaired glucose metabolism were detected only for nilotinib use, whereas these signals were not detected for other BCR-ABL inhibitors. Subgroup analyses showed a clearly increased nilotinib-associated reporting rate of impaired glucose metabolism in male and younger patients. Although FAERS- and JADER-based signal detection analyses cannot determine causality perfectly, our study suggests the effects on glucose metabolism are different between BCR-ABL inhibitors and provides useful information for the selection of appropriate BCR-ABL inhibitors.

Overcoming ABC transporter-mediated multidrug resistance: The dual role of tyrosine kinase inhibitors as multitargeting agents.

Resistance to conventional and target specific antitumor drugs still remains one of the major cause of treatment failure and patience death. This condition often involves ATP-binding cassette (ABC) transporters that, by pumping the drugs outside from cancer cells, attenuate the potency of chemotherapeutics and negatively impact on the fate of anticancer therapy. In recent years, several tyrosine kinase inhibitors (TKIs) (e.g., imatinib, nilotinib, dasatinib, ponatinib, gefitinib, erlotinib, lapatinib, vandetanib, sunitinib, sorafenib) have been reported to interact with ABC transporters (e.g., ABCB1, ABCC1, ABCG2, ABCC10). This finding disclosed a very complex scenario in which TKIs may behave as substrates or inhibitors depending on the expression of specific pumps, drug concentration, affinity for transporters and types of co-administered agents. In this context, in-depth investigation on TKI chemosensitizing functions might provide a strong rationale for combining TKIs and conventional therapeutics in specific malignancies. The reposition of TKIs as antagonists of ABC transporters opens a new way towards anticancer therapy and clinical strategies aimed at counteracting drug resistance. This review will focus on some paradigmatic examples of the complex and not yet fully elucidated interaction between clinical available TKIs (e.g. BCR-ABL, EGFR, VEGFR inhibitors) with the main ABC transporters implicated in multidrug resistance.

Synthesis and biological evaluation of novel aromatic-heterocyclic biphenyls as potent anti-leukemia agents.

As a continuation to our previous research, twenty-eight aromatic-heterocyclic biphenyls were designed and synthesized as novel Bcr-Abl inhibitors. The title compounds were investigated for their antiproliferative activities against wild K562 cells and Imatinib-resistant K562 cells (K562R). The results indicated that most of them exhibited potent Bcr-Abl inhibition and moderate antiproliferative potency against K562 cells. Furthermore, three compounds 3, 7 and 21 displayed moderate antiproliferative activities against K562R cells. Molecular docking indicated that 3 bound more tightly with Bcr-Abl(T315I) compared to Bcr-Abl(WT). The higher affinity was consistent with its relatively promising K562R cell growth inhibition. These aromatic-heterocyclic biphenyls could be considered as novel lead compound for optimized as Bcr-Abl(T315I) inhibitors. They provide a good starting point for the further development of novel anti-leukemia agents capable of dealing with clinical acquired resistance against Imatinib.

BCR-ABL inhibitors: updates in the management of patients with chronic-phase chronic myeloid leukemia.

OBJECTIVES: This article reviews recent clinical experiences with first-line and second-line second-generation BCR-ABL inhibitors and discusses considerations for selection of therapy for patients with chronic-phase chronic myeloid leukemia. METHODS: We reviewed recent publications on PubMed and abstracts from major congresses relevant to the topic. RESULTS: Therapeutic options for front-line treatment have increased with the approval of two second-generation BCR-ABL inhibitors, dasatinib and nilotinib. Both agents are also treatment options for patients with resistance or intolerance to front-line imatinib. More recently, bosutinib, ponatinib, and omacetaxine have also been approved for patients with resistance or intolerance to prior therapy. DISCUSSION: Expanded treatment options coupled with rapidly changing treatment guidelines have led to numerous questions regarding the selection and monitoring of therapy. Common concerns include how to best select therapy based upon patient-specific comorbidities, monitoring and interpretation of treatment outcomes, and optimization of dosing when side effects occur.