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Four afatinib derivatives were designed and modeled. These derivatives were compared to the known tyrosine-kinase inhibitors in treating Chronic Myeloid Leukemia, i.e., imatinib and ponatinib. The molecules were evaluated through computational methods, including docking studies, the non-covalent interaction index, Electron Localization and Fukui Functions, in silico ADMET analysis, QTAIM, and Heat Map analysis. The AFA(IV) candidate significantly increases the score value compared to afatinib. Furthermore, AFA(IV) was shown to be relatively similar to the ponatinib profile when evaluating a range of molecular descriptors. The addition of a methylpiperazine ring seems to be well distributed in the structure of afatinib when targeting the BCR-ABL enzyme, providing an important hydrogen bond interaction with the Asp381 residue of the DFG-switch of BCR-ABL active site residue and the AFA(IV) new chemical entities. Finally, in silico toxicity predictions show a favorable index, with some molecules presenting the loss of the irritant properties associated with afatinib in theoretical predictions. [ABSTRACT FROM AUTHOR]

Abstract Introduction The efficacy of BCR‐ABL tyrosine kinase inhibitors (TKIs) in treating chronic myelogenous leukemia and other malignancies is well‐documented. However, concerns about potential nephrotoxicity have raised questions. This study, conducted at Tikur Anbesa Specialized Hospital (TASH) in Addis Ababa, Ethiopia, aimed to investigate the association between TKIs and renal toxicities. Methods A hospital‐based cross‐sectional design was used to enroll 260 TASH patients actively receiving BCR‐ABL TKIs. Demographic information, diagnoses, treatment details, and laboratory test results were collected for each participant's Electronic Medical Record. The primary goal was to assess adverse renal events, a combination of events of a decrease in estimated glomerular filtration rate (eGFR) exceeding 30% from baseline, significant proteinuria, and a diagnosis of acute kidney injury (AKI) or chronic kidney disease (CKD). A logistic regression model was used to analyze the data and identify factors associated with developing adverse renal events. Results Our analysis revealed a statistically significant decrease in eGFR following treatment with TKIs. However, the observed rate of adverse renal events (13.1%) was lower than reported in some previous studies. Factors significantly associated with adverse renal events included longer TKI duration, male sex (protective), hypertension, HIV infection, and achieving complete molecular remission and/or a complete hematologic response. No significant associations were found with diabetes mellitus, age, angiotensin‐converting enzyme inhibitors use, or baseline creatinine level. Conclusions While this study found that BCR‐ABL TKIs can lead to a decline in eGFR, AKI, and CKD, it also demonstrated that they were relatively safer in our study population.

This document is a letter to the editor published in the journal Leukemia & Lymphoma. The letter discusses the predictive value of early molecular response (EMR) to tyrosine kinase inhibitors (TKIs) in pediatric patients with chronic myeloid leukemia (CML). The study analyzed 98 pediatric patients treated with the TKI imatinib and found that achieving EMR at 3 months was associated with a higher likelihood of achieving major molecular response (MMR) at 12 months. Patients who achieved EMR also had better event-free survival (EFS) compared to those who did not. The study suggests that EMR assessment can be a useful tool in managing pediatric CML. [Extracted from the article]

Introduction Methods Results Conclusion Accurate quantification of the BCR::ABL1 fusion gene in whole blood is pivotal for the clinical management of chronic myeloid leukemia (CML) patients. The fusion protein encoded by BCR::ABL1 can vary in size, depending on the BCR and/or ABL1 gene breakpoint. The vast majority of CML patients have a p210 BCR::ABL1 fusion gene (M‐BCR), which can be attributed to the presence of either e14a2 (b3a2) or e13a2 (b2a2) mRNA transcript junctions.Twenty‐five CML samples were analyzed in two different ISO15189‐accredited centers that both use an Europe Against Cancer‐based quantitative polymerase chain reaction (qPCR) protocol. Reanalysis of the sample set with transcript‐specific standard curves and digital droplet PCR (ddPCR) were performed.qPCR quantification revealed a significant (up to 1 log) difference specifically for the e13a2 transcript variant in contrast to e14a2 transcripts (Hodges–Lehman 4.29; p < 0.001). Reanalysis of the sample set with transcript‐specific standard curves abolishes the initial transcript‐specific difference (Hodges–Lehman 0.003; p = 0.8192). Comparison of transcript‐specific qPCR results of both centers with ddPCR, an absolute quantification method, showed a statically significant association, especially in the lower range, indicating the clinical utility of transcript‐specific or absolute quantification methods.Our data show that differences between transcript‐specific quantification might exist between centers, leading to potential clinical impact on the follow‐up of CML patients. The use of transcript‐specific standard curves for qPCR quantification, or absolute quantification, can significantly reduce these differences. Specific attention should be applied to the interpretation of quantification differences of CML patients that switch between diagnostic centers. [ABSTRACT FROM AUTHOR]

The BCR-ABL fusion gene, formed by the fusion of the breakpoint cluster region protein (BCR) and the Abl Oncogene 1, Receptor Tyrosine Kinase (ABL) genes, encodes the BCR-ABL oncoprotein, which plays a crucial role in leukemogenesis. Current therapies have limited efficacy in patients with chronic myeloid leukemia (CML) because of drug resistance or disease relapse. Identification of novel strategies to treat CML is essential. This study aims to explore the efficiency of novel CRISPR-associated protein 9 (Cas9)/dual-single guide RNA (sgRNA)-mediated disruption of the BCR-ABL fusion gene by targeting BCR and cABL introns. A co-expression vector for Cas9 green fluorescent protein (GFP)/dual-BA-sgRNA targeting BCR and cABL introns is constructed to produce lentivirus to affect BCR-ABL expression in CML cells. The effects of dual-sgRNA virus-mediated disruption of BCR-ABL are analyzed via the use of a genomic sequence and at the protein expression level. Cell proliferation, cell clonogenic ability, and cell apoptosis are assessed after dual sgRNA virus infection, and phosphorylated BCR-ABL and its downstream signaling molecules are detected. These effects are further confirmed in a CML mouse model via tail vein injection of Cas9-GFP/dual-BA-sgRNA virus-infected cells and in primary cells isolated from patients with CML. Cas9-GFP/dual-BA-sgRNA efficiently disrupts BCR-ABL at the genomic sequence and gene expression levels in leukemia cells, leading to blockade of the BCR-ABL tyrosine kinase signaling pathway and disruption of its downstream molecules, followed by cell proliferation inhibition and cell apoptosis induction. This method prolongs the lifespan of CML model mice. Furthermore, the effect is confirmed in primary cells derived from patients with CML.

Background: The present study attempts to assess the role of BCL-2 and p53 family of genes in chronic myeloid leukemia (CML) and correlation of their immunoreactivity with the status of remission on followup. Objectives: Primary objective of the study is to assess and score the expression of BCL2 and p53 in bone marrow trephine biopsies of cases of CML and to correlate the expression of these markers with the prognosis of the patients. Assessment of demographic distribution of CML were also included as secondary objective. Methods: Present study is a cross-sectional study conducted in the Department of Pathology, Govt. Medical College, Kozhikode from January 2017 to December 2020. The study population included confirmed cases of CML received in Pathology Department during the study period. 55 cases were selected. The paraffin embedded blocks of bone marrow trephine biopsy were retrieved and immunohistochemical testing were done in the department. Clinical details of patients were obtained from patient records. All variables needed for study were collected. Consecutive sampling technique was adopted for the study. Statistical analysis was done by chi square test. A p value less than 0.05 was considered as statistically significant. Results: Among the study population, majority (69%) of patients were in chronic phase at initial presentation. Most of the patients in chronic phase were in remission(62%). 25% of the study population presented in the blast crisis phase. Majority of the patients in blast crisis were not in remission and were in an elderly age group. Most of the patients presented with massive splenomegaly at diagnosis and only 5 patients didn't have significant organomegaly. It was found that there is an association between BCL2, haemoglobin, platelet and age with the status of remission (p<0.05) and there is no association between P53 and total count with the status of remission (p>0.05). Conclusion: These findings are in line with numerous studies that discovered a unique approach to eliminate quiescent stem cells in CML that cause relapse by targeting BCL-2 coupled with BCR-ABL and inhibiting the MDM2 protein that breaks down p53. [ABSTRACT FROM AUTHOR]

Simple Summary: Acute lymphoblastic leukemia is a malignant disease which is commonly treated with various chemotherapeutic drugs. Novel therapeutic options are gaining interest, most of them involving therapeutic antibodies. In a high-risk genetic subset called BCR-ABL1 positive acute lymphoblastic leukemia, tyrosine kinase inhibitors are successfully used. Tyrosine kinase inhibitors combine well with chemotherapy but might interfere with antibody therapy. The effects of tyrosine kinase inhibitors on antibody dependent cellular cytotoxicity are not fully understood. We therefore tested a novel inhibitor called asciminib that is tested in acute lymphoblastic leukemia and assessed its influence on immune cell activation by antibodies. We found that asciminib, in contrast to other agents such as dasatinib, does not interfere with antibody therapy and should therefore be tested in clinical trials for patients with acute lymphoblastic leukemia. B cell acute lymphoblastic leukemia (B-ALL) is characterized by an accumulation of malignant precursor cells. Treatment consists of multiagent chemotherapy followed by allogeneic stem cell transplantation in high-risk patients. In addition, patients bearing the BCR-ABL1 fusion gene receive concomitant tyrosine kinase inhibitor (TKI) therapy. On the other hand, monoclonal antibody therapy is increasingly used in both clinical trials and real-world settings. The introduction of rituximab has improved the outcomes in CD20 positive cases. Other monoclonal antibodies, such as tafasitamab (anti-CD19), obinutuzumab (anti-CD20) and epratuzumab (anti-CD22) have been tested in trials (NCT05366218, NCT04920968, NCT00098839). The efficacy of monoclonal antibodies is based, at least in part, on their ability to induce antibody-dependent cellular cytotoxicity (ADCC). Combination treatments, e.g., chemotherapy and TKI, should therefore be screened for potential interference with ADCC. Here, we report on in vitro data using BCR-ABL1 positive and negative B-ALL cell lines treated with rituximab and TKI. NK cell activation, proliferation, degranulation, cytokine release and tumor cell lysis were analyzed. In contrast to ATP site inhibitors such as dasatinib and ponatinib, the novel first-in-class selective allosteric ABL myristoyl pocket (STAMP) inhibitor asciminib did not significantly impact ADCC in our settings. Our results suggest that asciminib should be considered in clinical trials. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML) is induced by the expression of the fused tyrosine kinase BCR-ABL, which is caused by a chromosomal translocation. BCR-ABL inhibitors have been used to treat CML; however, the acquisition of resistance by CML cells during treatment is a serious issue. We herein demonstrated that BCR-ABL induced the expression of the RNA helicase DDX5 in K562 cells derived from CML patients in a manner that was dependent on its kinase activity, which resulted in cell proliferation and survival. The knockout of DDX5 decreased the expression of BIRC5 (survivin) and activated caspase 3, leading to apoptosis in K562 cells. Similar results were obtained in cells treated with FL118, an inhibitor of DDX5 and a derivative compound of camptothecin (CPT). Furthermore, FL118 potently induced apoptosis not only in Ba/F3 cells expressing BCR-ABL, but also in those expressing the BCR-ABL T315I mutant, which is resistant to BCR-ABL inhibitors. Collectively, these results revealed that DDX5 is a critical therapeutic target in CML and that FL118 is an effective candidate compound for the treatment of BCR-ABL inhibitor-resistant CML. [ABSTRACT FROM AUTHOR]

Nilotinib, a second-generation tyrosine kinase inhibitor for the treatment of chronic myelogenous leukemia (CML), inhibits Bcr-Abl tyrosine kinase activity and proliferation of Bcr-Abl-expressing cells, as well as other malignancies. In the present study, new nilotinib analogues were synthesized and fully characterized. A platelet aggregation assay was performed, and the expression of P-selectin and PAC-1, as well as the effect on the proliferation of healthy endothelial cells, were evaluated. The expression and antimetastatic effects of E-cadherin and N-cadherin were assessed. The analogues inhibited platelet aggregation in a statistically significant manner compared to nilotinib, while they exhibited a strong inhibitory effect on P-selectin and PAC-1 expression when activated by AA. All three analogues caused arrest in the mitosis phase of the HepG2 cell cycle, while analogue-1 exhibited the most potent apoptotic effect compared to nilotinib. Interestingly, none of them promoted apoptosis in HUVECs. All the analogues reduced the expression of E- and N-cadherin in different amounts, while the analogues-1 and -3 exhibited similar antimigratory effects on HepG2 cells. The results of this study reveal considerable potential to develop new tyrosine kinase inhibitors with improved antiplatelet and antitumor properties. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a novel approach called Pharmacophore Activity Delta for extracting outstanding pharmacophores from a chemogenomic dataset, with a specific focus on a kinase target known as BCR-ABL. The method involves constructing a Hasse diagram, referred to as the pharmacophore network, by utilizing the subgraph partial order as an initial step, leading to the identification of pharmacophores for further evaluation. A pharmacophore is classified as a ‘Pharmacophore Activity Delta’ if its capability to effectively discriminate between active vs inactive molecules significantly deviates (by at least δ standard deviations) from the mean capability of its related pharmacophores. Among the 1479 molecules associated to BCR-ABL binding data, 130 Pharmacophore Activity Delta were identified. The pharmacophore network reveals distinct regions associated with active and inactive molecules. The study includes a discussion on representative key areas linked to different pharmacophores, emphasizing structure–activity relationships.

Four afatinib derivatives were designed and modeled. These derivatives were compared to the known tyrosine-kinase inhibitors in treating Chronic Myeloid Leukemia, i.e., imatinib and ponatinib. The molecules were evaluated through computational methods, including docking studies, the non-covalent interaction index, Electron Localization and Fukui Functions, in silico ADMET analysis, QTAIM, and Heat Map analysis. The AFA(IV) candidate significantly increases the score value compared to afatinib. Furthermore, AFA(IV) was shown to be relatively similar to the ponatinib profile when evaluating a range of molecular descriptors. The addition of a methylpiperazine ring seems to be well distributed in the structure of afatinib when targeting the BCR-ABL enzyme, providing an important hydrogen bond interaction with the Asp381 residue of the DFG-switch of BCR-ABL active site residue and the AFA(IV) new chemical entities. Finally, in silico toxicity predictions show a favorable index, with some molecules presenting the loss of the irritant properties associated with afatinib in theoretical predictions.

The advent of tyrosine kinase inhibitors (TKIs) blocking BCR-ABL activity has revolutionized the therapeutic management of patients with chronic myeloid leukemia (CML). Adverse cutaneous reactions (ACRs) are common nonhematologic adverse events associated with the use of BCR-ABL TKIs. A characteristic pattern of eruption resembling keratosis pilaris (KP) has been described in patients treated with these drugs, especially nilotinib and dasatinib. The pathogenesis of this ACR is still unknown. This type of reaction appears to be uncommon with imatinib. Here, we report the case of an elderly patient with an asymptomatic KP-like eruption, which appeared one month after starting treatment with imatinib for CML. The case presentation is accompanied by a review of similar reactions in patients with CML treated with BCR-ABL inhibitors, attempting to make an excursus on the molecular targets of such drugs and possible mechanisms underlying this ACR. [ABSTRACT FROM AUTHOR]

Philadelphia chromosome positive (Ph+) acute lymphoblastic lymphoma (ALL) is an uncommon subtype of ALL in children, seen in 2–5% cases. Diagnostic evaluation includes conventional karyotyping and detection of BCR-ABL1 translocation by fluorescence in-situ hybridization (FISH) or reverse transcriptase polymerase chain reaction (RT-PCR). For children, the frontline management includes combination of intensive chemotherapy along with imatinib (300–340 mg/m2/d) or dasatinib (60–80 mg/m2/d). Imatinib/dasatinib should be introduced in induction as soon as results for BCR-ABL are available. Minimal residual disease (MRD) monitoring is essential; multi-parametric flowcytometry and immunoglobulin/T-cell receptor rearrangement PCR are the preferred methods. Intrathecal therapy with at least 12 doses of methotrexate is adequate for central nervous system (CNS) prophylaxis, but cranial radiation is necessary for CNS3 involvement. Allogeneic hematopoietic stem cell transplantation (HSCT) in first remission may be considered in high-risk cases (persistent MRD positivity/induction failure). Maintenance therapy with tyrosine kinase inhibitors (TKI) in children is debatable, with potential concerns for long term adverse effects. At relapse, the choice of TKI is guided by the presence of BCR-ABL tyrosine kinase domain resistance mutations, although the frequency of resistance mutations in children are lower. Allogeneic HSCT is essential for consolidation in second remission, if not done. Ph-like ALL is a newly recognized molecular entity, with gene expression profile similar to Ph+ALL and poor survival outcomes. In resource-constrained settings, a stepwise cost-effective diagnostic evaluation should be considered among high-risk patients without recurrent genetic abnormalities. Current treatment strategies remain similar to Ph-negative ALL. Enrolment in clinical trials is encouraged for such children to evaluate potential targeted agents in this subtype. [ABSTRACT FROM AUTHOR]

Although improved survival in children with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL) has been demonstrated in trials, the outcome appears to be inferior in low- and middle-income countries (LMIC). Methods A file review of children aged ≤ 15 years diagnosed with Ph-ALL from 2010 to 2019 was performed. Minimal residual disease (MRD) was assessed by flow-cytometry. Real-time polymerase chain reaction (qRT-PCR) was used to quantify the BCR::ABL1 transcripts during treatment. Results The mean age of the 20 patients in the study was 91 months. Of 19 patients in whom the BCR::ABL1 transcript was confirmed, 10(50%) had P210, 7(35%) had P190, and two showed dual expression. The mean dose of imatinib that was administered was 294 ± 41 mg/m2/day. qRT-PCR for BCR::ABL1 was < 0.01% in all patients who were in remission or had a late relapse and was ≥ 0.01% in patients who had an early relapse. Two patients underwent HSCT. The 3-year event-free survival (EFS) was 35.0 ± 10.7%. Patients with a good prednisolone response (GPR) and a negative end-of-induction MRD demonstrated a superior EFS to those who lacked either or both (80.0 ± 17.9% vs. 16.7 ± 15.2%, P = 0.034). Conclusion The 3-year EFS of 20 children with Ph-ALL treated with chemotherapy and TKI was < 50%. An unusually high proportion of patients with p210 transcript expression; sub-optimal TKI dosing and lesser intensity of chemotherapy, due to the concern of high treatment-related mortality in LMIC are possible reasons for the poor outcome. Conventional treatment response parameters such as GPR and MRD predict outcomes in Ph-ALL. qRT-PCR for BCR::ABL1 may have a role in predicting early relapse. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease characterized by the presence of the BCR-ABL fusion gene, which results from the Philadelphia chromosome. Since the introduction of tyrosine kinase inhibitors (TKI) such as imatinib mesylate (IM), the clinical outcomes for patients with CML have improved significantly. However, IM resistance remains the major clinical challenge for many patients, underlining the need to develop new drugs for the treatment of CML. The basis of CML cell resistance to this drug is unclear, but the appearance of additional genetic alterations in leukemic stem cells (LSCs) is the most common cause of patient relapse. However, several groups have identified a rare subpopulation of CD34+ stem cells in adult patients that is present mainly in the bone marrow and is more immature and pluripotent; these cells are also known as very small embryonic-like stem cells (VSELs). The uncontrolled proliferation and a compromised differentiation possibly initiate their transformation to leukemic VSELs (LVSELs). Their nature and possible involvement in carcinogenesis suggest that they cannot be completely eradicated with IM treatment. In this study, we demonstrated that cells from CML patients with the VSELs phenotype (LVSELs) similarly harbor the fusion protein BCR-ABL and are less sensitive to apoptosis than leukemic HSCs after IM treatment. Thus, IM induces apoptosis and reduces the proliferation and mRNA expression of Ki67 more efficiently in LHSCs than in leukemic LVSELs. Finally, we found that the expression levels of some miRNAs are affected in LVSELs. In addition to the tumor suppressor miR-451, both miR-126 and miR-21, known to be responsible for LSC leukemia-initiating capacity, quiescence, and growth, appear to be involved in IM insensitivity of LVSELs CML cell population. Targeting IM-resistant CML leukemic stem cells by acting via the miRNA pathways may represent a promising therapeutic option. [ABSTRACT FROM AUTHOR]

Background: Due to its remarkable efficacy in producing hematologic, cytogenetic, and molecular remissions, the FDA approved Imatinib as the first-line treatment for newly diagnosed Chronic Myeloid Leukemia (CML) patients. However, in some patients, failure to completely eradicate leukemic cells and the escape of these cells from death will lead to the development of resistance to Imatinib, and many are concerned about the prospects of this Tyrosine Kinase Inhibitor (TKI). It has been documented that the compensatory overexpression of c-Myc is among the most critical mechanisms that promote drug efflux and resistance in CML stem cells. Methods: In order to examine the potential of c-Myc inhibition through the use of 10058-F4 to enhance the anti-leukemic properties of Imatinib, we conducted trypan blue and MTT assays. Additionally, we employed flow cytometric analysis and qRT-PCR to assess the effects of this combination on cell cycle progression and apoptosis. Results: The findings of our study indicate that the combination of 10058-F4 and Imatinib exhibited significantly stronger anti-survival and anti-proliferative effects on CML-derived-K562 cells in comparison to either agent administered alone. It is noteworthy that these results were also validated in the CML-derived NALM-1 cell line. Molecular analysis of this synergistic effect revealed that the inhibition of c-Myc augmented the efficacy of Imatinib by modulating the expression of genes related to cell cycle, apoptosis, autophagy, and proteasome. Conclusions: Taken together, the findings of this investigation have demonstrated that the suppression of the c-Myc oncoprotein through the use of 10058-F4 has augmented the effectiveness of Imatinib, suggesting that this amalgamation could offer a fresh perspective on an adjunctive treatment for individuals with CML. Nevertheless, additional scrutiny, encompassing in-vivo examinations and clinical trials, is requisite. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach called Pharmacophore Activity Delta for extracting outstanding pharmacophores from a chemogenomic dataset, with a specific focus on a kinase target known as BCR-ABL. The method involves constructing a Hasse diagram, referred to as the pharmacophore network, by utilizing the subgraph partial order as an initial step, leading to the identification of pharmacophores for further evaluation. A pharmacophore is classified as a 'Pharmacophore Activity Delta' if its capability to effectively discriminate between active vs inactive molecules significantly deviates (by at least δ standard deviations) from the mean capability of its related pharmacophores. Among the 1479 molecules associated to BCR-ABL binding data, 130 Pharmacophore Activity Delta were identified. The pharmacophore network reveals distinct regions associated with active and inactive molecules. The study includes a discussion on representative key areas linked to different pharmacophores, emphasizing structure–activity relationships. [ABSTRACT FROM AUTHOR]

Due to resistance and BCR-ABLT315I-mutated, CML remains a clinical challenge. It needs new potential therapeutic targets to overcome CML resistance related to BCR-ABL. Our research revealed that the deubiquitinating enzyme USP28 was highly expressed in BCR-ABL-dependent CML patients. Similarly, a high expression of USP28 was found in the K562 cell line, particularly in the imatinib-resistant strains. Notably, USP28 directly interacted with BCR-ABL. Furthermore, when BCR-ABL and its mutant BCR-ABLT315I were overexpressed in K562-IMR, they promoted the expression of IFITM3. However, when small molecule inhibitors targeting USP28 and small molecule degraders targeting BCR-ABL were combined, they significantly inhibited the expression of IFITM3. The experiments conducted on tumor-bearing animals revealed that co-treated mice showed a significant reduction in tumor size, effectively inhibiting the progression of CML tumors. In summary, USP28 promoted the proliferation and invasion of tumor cells in BCR-ABL-dependent CML by enhancing the expression of IFITM3. Moreover, imatinib resistance might be triggered by the activation of the USP28-BCR-ABL-IFITM3 pathway. Thus, the combined inhibition of USP28 and BCR-ABL could be a promising approach to overcome CML resistance dependent on BCR-ABL.

Chronic myelogenous leukemia (CML) is characterized by the constitutive activation of BCR-ABL tyrosine kinase. Imatinib was approved for CML therapy, however, BCR-ABL-dependent drug resistance, especially BCR-ABL-T315I mutation, restricts its clinical application. In this study, we reported anthraquinone lactone AS1041, a synthesized derivative of marine natural compound Aspergiolide A, showed anti-leukemia effect in vitro and in vivo by promoting cell senescence. Mechanistic study revealed the pro-senescence effect of AS1041 was dependent on oxidative stress-induced DNA damage, and the resultant activation of P53/P21 and P16INK4a/Rb. Also, AS1041 promoted ubiquitin proteasome system (UPS)-mediated BCR-ABL degradation, which also contributed to AS1041-induced senescence. In vivo, AS1041-induced senescence promoted tumor growth inhibition. In summary, the in vitro and in vivo antitumor effect of AS1041 suggests it can serve as a pro-senescence agent for alternative antileukemia therapy and imatinib-resistant cancer therapy by enhancing cellular oxidative stress and BCR-ABL degradation.

Priapism in chronic myeloid leukemia (CML) appears to be an infrequent manifestation as well as a crucial emergency. Here, we report a 45-year-old male presenting with involuntary and persistent penile erection since last 7 days. He was treated with needle aspiration of corpora cavernosa. In post operative labs he was found to have anemia and hyperleukocytosis. Patient was subsequently diagnosed with chronic myeloid leukemia. [ABSTRACT FROM AUTHOR]

Objective: BCR-ABL1 kinase domain (KD) mutations can lead to resistance to first- and second-generation tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). Here, we present the first report of the spectrum of mutations in the BCR-ABL1 KD of CML patients from Azerbaijan.Materials and methods: Samples for mutation screening were obtained from patients experiencing resistance to first line TKIs or from patients in acceleration phase (AP) or blast crisis (BC) at the time of diagnosis. The cDNA region corresponding to BCR-ABL1 KD was sequenced by pyrosequencing method. The χ2 test was used to assess the association of categorical variables between mutation-positive and -negative groups. In addition, the Kaplan-Meier method was applied to generate survival curves.Results: Eight different point mutations were identified in 22 (13.4%) out of 163 CML patients experiencing resistance to TKIs. The types of mutations detected were as follows: Contact binding site mutations 50% (11), SH2 domain mutations 27.4% (six), P-loop mutations 18.1% (four), and SH3 domain mutations accounting for 4.5% (one). The most common mutation was T315I, accounting for 5% (n = 8) of all patients. Significant association was identified between BCR-ABL1 mutations and additional chromosomal aberrations as well as between the mutations and disease phases (p < 0.05). Twelve out of 22 patients with BCR-ABL1 mutations and seven out of eight with T315I were in BC. Overall survival (OS) of the patients with BCR-ABL1 mutations was significantly lower comparing to the patients with no mutation (p < 0.05) and 8 patients with T315I mutation presented OS of 0%.Conclusion: T315I was the most commonly identified BCR-ABL1 mutation in TKI-resistant CML patients of Azerbaijani origin, being associated with disease progression and poor OS.

Summary: Although tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of chronic myeloid leukaemia (CML), TKI resistance remains a major challenge. Here, we demonstrated that plant homeodomain finger protein 8 (PHF8), a histone demethylase was aberrantly enriched in CML samples compared to healthy controls. PHF8 inhibited CML cell differentiation and promoted CML cell proliferation. Furthermore, the proliferation‐inhibited function of PHF8‐knockdown have stronger effect on imatinib mesylate (IM)‐resistant CML cells. Mechanistically, we identified that PHF8 as a transcriptional modulator interacted with the promoter of the BCR::ABL1 fusion gene and alters the methylation levels of H3K9me1, H3K9me2 and H3K27me1, thereby promoting BCR::ABL1 transcription. Overall, our study suggests that targeting PHF8, which directly regulates BCR::ABL1 expression, is a useful therapeutic approach for CML. [ABSTRACT FROM AUTHOR]

Human erythroleukemic K562 cells represent the prototypical cell culture model of chronic myeloid leukemia (CML). The cells are pseudo-triploid and positive for the Philadelphia chromosome. Therefore, K562 cells have been widely used for investigating the BCR/ABL1 oncogene and the tyrosine kinase inhibitor, imatinib-mesylate. Further, K562 cells overexpress transferrin receptors (TfR) and have been used as a model for targeting cytotoxic therapies, via receptor-mediated endocytosis. Here, we have characterized K562 cells focusing on the karyotype of cells in prolonged culture, regulation of expression of TfR in wildtype (WT) and doxorubicin-resistant cells, and responses to histone deacetylase inhibition (HDACi). Karyotype analysis indicates novel chromosomes and gene expression analysis suggests a shift of cultured K562 cells away from patient-derived leukemic cells. We confirm the high expression of TfR on K562 cells using immunofluorescence and cell-surface receptor binding radioassays. Importantly, high TfR expression is observed in patient-derived cells, and we highlight the persistent expression of TfR following doxorubicin acquired resistance. Epigenetic analysis indicates that permissive histone acetylation and methylation at the promoter region regulates the transcription of TfR in K562 cells. Finally, we show relatively high expression of HDAC enzymes in K562 cells and demonstrate the chemotoxic effects of HDACi, using the FDA-approved hydroxamic acid, vorinostat. Together with a description of morphology, infrared spectral analysis, and examination of metabolic properties, we provide a comprehensive characterization of K562 cells. Overall, K562 cell culture systems remain widely used for the investigation of novel therapeutics for CML, which is particularly important in cases of imatinib-mesylate resistance. [ABSTRACT FROM AUTHOR]

Chronic myelogenous leukemia (CML) is a myeloproliferative neoplasm resulting from the emergence of abnormal hematopoietic stem cells carrying a Bcr-Abl oncoprotein as a result of a reciprocal translocation between the chromosomes 9 and 22. The main elements of the disease's pathogenesis are caused by both increased tyrosine kinase activity of the Abl protein and the role of a Bcr part of the hybrid protein. The presence of PH domain in the Bcr determines its interaction with PI(3)P of the phagosomal membrane. We demonstrated that this interaction is accompanied by a colocalization of the Bcr with the FNBPI protein in the phagosomes of J774 macrophage cells. A model of the effect of the Bcr-Abl oncoprotein on the formation of the ROS excess with CML due to uncontrolled expression of phagosomal NADP oxidase is presented. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML) is induced by the expression of the fused tyrosine kinase BCR-ABL, which is caused by a chromosomal translocation. BCR-ABL inhibitors have been used to treat CML; however, the acquisition of resistance by CML cells during treatment is a serious issue. We herein demonstrated that BCR-ABL induced the expression of the RNA helicase DDX5 in K562 cells derived from CML patients in a manner that was dependent on its kinase activity, which resulted in cell proliferation and survival. The knockout of DDX5 decreased the expression of BIRC5 (survivin) and activated caspase 3, leading to apoptosis in K562 cells. Similar results were obtained in cells treated with FL118, an inhibitor of DDX5 and a derivative compound of camptothecin (CPT). Furthermore, FL118 potently induced apoptosis not only in Ba/F3 cells expressing BCR-ABL, but also in those expressing the BCR-ABL T315I mutant, which is resistant to BCR-ABL inhibitors. Collectively, these results revealed that DDX5 is a critical therapeutic target in CML and that FL118 is an effective candidate compound for the treatment of BCR-ABL inhibitor-resistant CML.

Nilotinib, a second-generation tyrosine kinase inhibitor for the treatment of chronic myelogenous leukemia (CML), inhibits Bcr-Abl tyrosine kinase activity and proliferation of Bcr-Abl-expressing cells, as well as other malignancies. In the present study, new nilotinib analogues were synthesized and fully characterized. A platelet aggregation assay was performed, and the expression of P-selectin and PAC-1, as well as the effect on the proliferation of healthy endothelial cells, were evaluated. The expression and antimetastatic effects of E-cadherin and N-cadherin were assessed. The analogues inhibited platelet aggregation in a statistically significant manner compared to nilotinib, while they exhibited a strong inhibitory effect on P-selectin and PAC-1 expression when activated by AA. All three analogues caused arrest in the mitosis phase of the HepG2 cell cycle, while analogue-1 exhibited the most potent apoptotic effect compared to nilotinib. Interestingly, none of them promoted apoptosis in HUVECs. All the analogues reduced the expression of E- and N-cadherin in different amounts, while the analogues-1 and -3 exhibited similar antimigratory effects on HepG2 cells. The results of this study reveal considerable potential to develop new tyrosine kinase inhibitors with improved antiplatelet and antitumor properties.

Heterobifunctional proteolysis-targeting chimeras (PROTACs) offer a promising cancer treatment avenue by efficiently degrading unwanted cellular proteins. A recent study from Zhang et al. demonstrated the successful utilization of the N-end rule in PROTAC design, allowing for a modular degradation rate tailored to the oncogenic driver BCR–ABL. [ABSTRACT FROM AUTHOR]

Isoalantolactone (Iso) is a bioactive lactone isolated from the root of Inula helenium L, which has been reported to have many pharmacological effects. To investigate the role and mechanism of isoalantolactone in chronic myeloid leukemia (CML), we first investigated isoalantolactone's anti-proliferative effects on imatinib-sensitive and imatinib-resistant CML cells by CCK8. Flow cytometry was used to detect isoalantolactone-induced cell apoptosis. Survivin was overexpressed in KBM5 and KBM5T315I cells using the lentivirus vector pSIN-3×flag-PURO. In KBM5 and KBM5T315I cells, shRNA was used to knockdown survivin. Cellular Thermal Shift Assay (CETSA) was used to detect the interaction between isoalantolactone and survivin. The ubiquitin of survivin induced by isoalantolactone was detected through immunoprecipitation. Quantitative polymerase-chain reaction (Q-PCR) and western blotting were used to detect the levels of mRNA and protein. Isoalantolactone inhibits the proliferation and promotes apoptosis of imatinib-resistant CML cells. Although isoalantolactone inhibits the proteins of BCR-ABL and survivin, it cannot inhibit survivin and BCR-ABL mRNA levels. Simultaneously, it was shown that isoalantolactone can degrade survivin protein by increasing ubiquitination. It was demonstrated that isoalantolactone-induced survivin mediated downregulation of BCR-ABL protein. It was also revealed that isoalantolactone triggered BCR-ABL protein degradation via caspase-3. Altogether, isoalantolactone inhibits survivin through the ubiquitin proteasome pathway, and mediates BCR-ABL downregulation in a caspase-3 dependent manner. These data suggest that isoalantolactone is a natural compound, which can be used as a potential drug to treat TKI-resistant CML. [ABSTRACT FROM AUTHOR]

Myeloproliferative neoplasm (MPN) is a clonal proliferation of the haematopoietic stem cells leading to activated tyrosine kinase signaling activity. Myeloproliferative neoplasm is classified into BCR-ABL positive chronic myeloid leukemia (CML) and BCR-ABL negative MPN which harbors JAK2 V617F mutation in most cases. The genetic combination of BCR-ABL and JAK2 V617F mutation is rare with estimated frequency of 0.4% based on recent study. Herein, we reported a case of a man diagnosed with CML detected by fluorescence in-situ hybdridisation (FISH) showing atypical BCR-ABL fusion pattern in 29% nucleated cells (cut-off levels ≥5% for positive signals) in the presence of JAK2 V617F mutation. However, the BCR-ABL transcript was not detected by the conventional reverse transcriptasepolymerase chain reaction (RT-PCR) method which was specific for major fragments. Interestingly, complete hematological remission was not achieved despite initiation of tyrosine kinase inhibitor (Imatinib). In conclusion, it is imperative to scrutinise CML cases for concomitant JAK2 V617F mutation especially patients with atypical clinical or laboratory findings. Therefore, close monitoring with clinical and ancillary technique especially FISH and molecular methods such as DNA sequencing were crucial to help achieve complete hematological, cytogenetic and deep molecular response alongside targeted therapy. [ABSTRACT FROM AUTHOR]

Abstract Background Chronic myeloid leukemia (CML) is a multifactorial clonal myeloid neoplasm that mainly arises from the Philadelphia chromosome. Even though imatinib mesylate (IM) is considered the gold standard for first-line treatment, a number of CML patients have shown IM resistance that can be influenced by many factors, including pharmacogenetic variability. The present study examined whether two common single nucleotide polymorphisms (SNPs) of ABCG2 (G34A and C421A) contribute to IM resistance and/or good responses. Material and methods A total of 72 CML patients were genotyped with high-resolution melting (HRM) and restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). We also determined the cytogenetic and hematological response, as evaluable factors for measuring response to imatinib. Results In the current study, we explored the relationship between the different variants of ABCG2 G34A and C421A and clinical response to imatinib among CML patients. There were no statistically significant differences between genotypes of C421A and G34A and allele frequencies among the resistant and responder groups, with response to IM (P > 0.05). Also, we found no statistically significant association between genotypes and cytogenetic and hematological responses. Conclusion This is the first study to investigate the association between genotypes of the G34A and C421A SNPs and the outcome of IM treatment in Iranian population. As a whole, genotyping of these SNPs is unhelpful in predicting IM response in CML patients.

Objective: We herein describe two cases of de novo lymphoid blastic transformation in patients with no history of chronic-phase chronic myeloid leukemia (CP-CML), both of whom were labeled initially as Philadelphia positive B-Acute Lymphoblastic Leukemia (B-ALL).Methods: The first patient was an 18-year-old male who presented with subjective fever, intentional weight loss, generalized fatigue, and headache. Investigations showed leukocytosis (312 × 10^3/ul), thrombocytopenia and anemia. Flowcytometry was consistent with B-ALL, with aberrant expression of CD13 and CD33. He was found to be positive for BCR::ABL by FISH, and karyotype confirmed the presence of the Philadelphia chromosome. He received a pediatric-inspired regimen and achieved remission with negative measurable residual disease (MRD) by flowcytometry, however with persistent cytogenetic abnormality using FISH for BCR::ABL. FISH abnormality was confirmed to be in the myeloid compartment using myeloid segregated FISH, reclassifying the disease to de novo lymphoid blastic phase CML. The second patient was a 52-year-old male who presented with fever and shortness of breath. Bilateral cervical lymphadenopathy and hepatosplenomegaly were identified on examination, and investigations showed leukocytosis (371 × 10^3/ul), anemia, and thrombocytopenia. BCR::ABL rearrangement was identified by FISH, molecular testing, and confirmed with karyotype. He was treated with Mini-CVD and Ponatinib, achieved complete remission with negative MRD by flow cytometry, however molecular studies showed BCR-ABL1 level at 58% IS indicating a persistent cytogenetic abnormality.Results: De novo lymphoid blastic-phase CML can therefore be difficult to differentiate from Philadelphia positive B-ALL due to their overlapping clinical and laboratory picture, implying the need to do myeloid compartment evaluation at the time of diagnosis.Conclusion: With recent progress in the treatment of Philadelphia positive B-ALL, including the role of transplant with the use of novel agents, a better characterization of this disease entity in retrospective and prospective trials is warranted.

Abstract Background The BCR-ABL fusion protein is the key factor that results in the occurrence of chronic myeloid leukemia (CML). Imatinib (IM) is a targeted inhibitor of BCR-ABL to achieve complete remission. However, remission failure occurs due to acquired resistance caused by secondary BCR-ABL mutations, underlining the need for novel BCR-ABL-targeting strategies. Circular RNAs (circRNAs) derived from tumor-related genes have been revealed as possible therapeutic targets for relevant cancers in recent investigations. In CML, the roles of this kind of circRNA are yet obscure. Methods Firstly, RT-qPCR was used for determining circCRKL expression level in cell lines and clinical samples, RNase R and Actinomycin D were employed to verify the stability of circCRKL. Then shRNAs were designed to specifically knockdown circCRKL. The function of circCRKL in vitro was investigated using CCK-8, colony formation assay, and flow cytometry, while a CML mouse model was constructed to explore the function in vivo. Finally, a dual-luciferase reporter assay, RNA pull-down, RNA immunoprecipitation, and rescue experiments were conducted to investigate the mechanism of circCRKL functioning. Results Here, we determined circCRKL, which derives from CML-relevant gene CRKL, is over-expressed in BCR-ABL+ cells. Then we noticed knocking down circCRKL using shRNA lentivirus dampens the proliferation of BCR-ABL+ cells both in vitro and in vivo, and augments susceptibility of resistant cells to IM. Intriguingly, we observed that circCRKL has a considerable impact on the expression level of BCR-ABL. Mechanistically, circCRKL could behave like a decoy for miR-877-5p to enhance the BCR-ABL level, allowing BCR-ABL+ cells to maintain viability. Conclusions Overall, the current study uncovers that circCRKL is specifically expressed and regulates BCR-ABL expression level via decoying miR-877-5p in BCR-ABL+ cells, highlighting that targeting circCRKL along with imatinib treatment could be utilized as a potential therapeutic strategy for CML patients.

Purpose of Review: To provide a detailed overview of cardiovascular adverse events associated with the use of tyrosine kinase inhibitors across different tumor types. Recent Findings: Despite an undeniable survival advantage of tyrosine kinase inhibitors (TKIs) in patients with hematologic or solid malignancies, the accompanying off-target cardiovascular adverse events can be life-threatening. In patients with B cell malignancies, the use of Bruton tyrosine kinase inhibitors has been associated with atrial and ventricular arrhythmias, as well as hypertension. Cardiovascular toxic profiles are heterogeneous among the several approved breakpoint cluster region (BCR)-ABL TKIS. Notably, imatinib might be cardioprotective. Vascular endothelial growth factor TKIs, constituting the central axis in the treatment of several solid tumors, including renal cell carcinoma and hepatocellular carcinoma, have strongly been associated with hypertension and arterial ischemic events. Epidermal growth factor TKIs as therapy for advanced non-small cell lung cancer (NSCLC) have been reported to be infrequently associated with heart failure and QT prolongation. Summary: While tyrosine kinase inhibitors have been demonstrated to increase overall survival across different types of cancers, special consideration should be given to cardiovascular toxicities. High-risk patients can be identified by undergoing a comprehensive workup at baseline. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease characterized by the presence of the BCR-ABL fusion gene, which results from the Philadelphia chromosome. Since the introduction of tyrosine kinase inhibitors (TKI) such as imatinib mesylate (IM), the clinical outcomes for patients with CML have improved significantly. However, IM resistance remains the major clinical challenge for many patients, underlining the need to develop new drugs for the treatment of CML. The basis of CML cell resistance to this drug is unclear, but the appearance of additional genetic alterations in leukemic stem cells (LSCs) is the most common cause of patient relapse. However, several groups have identified a rare subpopulation of CD34+ stem cells in adult patients that is present mainly in the bone marrow and is more immature and pluripotent; these cells are also known as very small embryonic-like stem cells (VSELs). The uncontrolled proliferation and a compromised differentiation possibly initiate their transformation to leukemic VSELs (LVSELs). Their nature and possible involvement in carcinogenesis suggest that they cannot be completely eradicated with IM treatment. In this study, we demonstrated that cells from CML patients with the VSELs phenotype (LVSELs) similarly harbor the fusion protein BCR-ABL and are less sensitive to apoptosis than leukemic HSCs after IM treatment. Thus, IM induces apoptosis and reduces the proliferation and mRNA expression of Ki67 more efficiently in LHSCs than in leukemic LVSELs. Finally, we found that the expression levels of some miRNAs are affected in LVSELs. In addition to the tumor suppressor miR-451, both miR-126 and miR-21, known to be responsible for LSC leukemia-initiating capacity, quiescence, and growth, appear to be involved in IM insensitivity of LVSELs CML cell population. Targeting IM-resistant CML leukemic stem cells by acting via the miRNA pathways may represent a promising therapeutic option.

Pleural effusion is rarely associated with chronic myeloid leukemia (CML). CML is asymptomatic and incidentally detected in majority of the patients. Few present with symptoms related to splenomegaly. Pleural effusion as the presenting symptom in CML has rarely been reported in the literature. We report the case of 58-year-old woman who presented with pleural effusion. Working diagnosis was lung malignancy or lymphoma. However, investigations and examination revealed CML in blast crisis. The patient was then treated with dasatinib, and she responded well. The exact mechanism for pleural effusion in CML is not known. It could be due to leukemia infiltration, extramedullary hematopoiesis, capillary obstruction, infections, or drug induced. Our case showed features compatible with extramedullary hematopoiesis. CML can rarely present with pleural effusion. Simple tests such as blood smear examination and pleural fluid cytology will aid in the diagnosis. The physicians and pathologists should be aware of this association.

Ihda Kartika Syamsuddin,1 Paulus Budiono Notopuro2 1Department of Clinical Pathology, Faculty of Medicine Universitas Airlangga, Surabaya, Indonesia; 2Department of Clinical Pathology, Faculty of Medicine Universitas Airlangga, Dr. Soetomo General Hospital, Surabaya, IndonesiaCorrespondence: Paulus Budiono Notopuro, Email paulus-b-n@fk.unair.ac.idAbstract: Chronic myeloid leukemia (CML) is a type of myeloproliferative neoplasm (MPN) in which granulocytes are the primary proliferating cells. CML in pediatric patients (juvenile CML) is an uncommon MPN, representing 2– 3% of children newly diagnosed with leukemia. Sensorineural hearing loss that progresses rapidly is an uncommon early sign of a hematological disorder in patients with CML. This article presents the case of a 10-year-old patient with complaints of bilateral hearing loss for 2 weeks. Pure-tone audiometry indicated sensorineural hearing loss of the left ear and mixed hearing loss of the right ear. After an in-depth evaluation of a bone marrow smear and positivity for the BCR-ABL fusion gene, it was concluded that the patient had chronic-phase juvenile CML. However, hearing loss recovery after hydroxyurea therapy could not be observed because the patient died after suffering an uncontrolled seizure on day 14 of hospitalization.Keywords: sensorineural hearing loss, chronic myeloid leukemia, BCR-ABL, pediatric, cancer

Background: Chronic myeloid leukemia (CML) is a multifactorial clonal myeloid neoplasm that mainly arises from the Philadelphia chromosome. Even though imatinib mesylate (IM) is considered the gold standard for first-line treatment, a number of CML patients have shown IM resistance that can be influenced by many factors, including pharmacogenetic variability. The present study examined whether two common single nucleotide polymorphisms (SNPs) of ABCG2 (G34A and C421A) contribute to IM resistance and/or good responses. Material and methods: A total of 72 CML patients were genotyped with high-resolution melting (HRM) and restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). We also determined the cytogenetic and hematological response, as evaluable factors for measuring response to imatinib. Results: In the current study, we explored the relationship between the different variants of ABCG2 G34A and C421A and clinical response to imatinib among CML patients. There were no statistically significant differences between genotypes of C421A and G34A and allele frequencies among the resistant and responder groups, with response to IM (P > 0.05). Also, we found no statistically significant association between genotypes and cytogenetic and hematological responses. Conclusion: This is the first study to investigate the association between genotypes of the G34A and C421A SNPs and the outcome of IM treatment in Iranian population. As a whole, genotyping of these SNPs is unhelpful in predicting IM response in CML patients. [ABSTRACT FROM AUTHOR]

Background: BCR-ABL mutation on the Philadelphia chromosome is the key driver of chronic myeloid leukemia (CML) pathogenesis. However, there are certain cases of myeloproliferative neoplasms (MPN) wherein no inherent driver mutation is detected resulting in clinical phenotype. It is important to identify key genes and pathways in driving the disease. The aim of the study was to use a gene-based omics approach to molecularly characterize these mutationpositive and negative cases to further strengthen diagnostics and precision medicine. Methods: A microarray profiling was done on CD34 positive cells isolated from two BCR-ABL positive and five BCR-ABL negative samples. JAK2V617F mutation testing was also done to rule out the presence of any other mutation in the latter group. The fold change cut-off was taken as ±1.5 with p=0.5 for significant genes. The gene network and pathway analysis were done using DAVID and STRING software. Results: The genes upregulated in BCR-ABL negative samples were shown to be involved in immune regulation, signal transduction and T- and B-cell signalling. The protein-protein interaction network of upregulated genes in these samples were enriched for various immunomodulatory genes such as HLADP, HLADQ, IL7R, CCR7, CD3 subtypes. These genes further formed a network with signal transduction genes such as LCK, FYN, RAG1, DOCK1, AKT3, SMAD3, LEF1. Conclusion: The results suggested a modulation of immune response genes and its subsequent effect on oncogenic signalling in BCR-ABL negative samples as compared to BCR-ABL positive samples. The protein network analysis was enriched for genes involved in Src, TGF-beta and PI3K-AKT pathway contributing to the proliferation of neoplastic clone. [ABSTRACT FROM AUTHOR]

We herein describe two cases of de novo lymphoid blastic transformation in patients with no history of chronic-phase chronic myeloid leukemia (CP-CML), both of whom were labeled initially as Philadelphia positive B-Acute Lymphoblastic Leukemia (B-ALL). The first patient was an 18-year-old male who presented with subjective fever, intentional weight loss, generalized fatigue, and headache. Investigations showed leukocytosis (312 × 10^3/ul), thrombocytopenia and anemia. Flowcytometry was consistent with B-ALL, with aberrant expression of CD13 and CD33. He was found to be positive for BCR::ABL by FISH, and karyotype confirmed the presence of the Philadelphia chromosome. He received a pediatric-inspired regimen and achieved remission with negative measurable residual disease (MRD) by flowcytometry, however with persistent cytogenetic abnormality using FISH for BCR::ABL. FISH abnormality was confirmed to be in the myeloid compartment using myeloid segregated FISH, reclassifying the disease to de novo lymphoid blastic phase CML. The second patient was a 52-year-old male who presented with fever and shortness of breath. Bilateral cervical lymphadenopathy and hepatosplenomegaly were identified on examination, and investigations showed leukocytosis (371 × 10^3/ul), anemia, and thrombocytopenia. BCR::ABL rearrangement was identified by FISH, molecular testing, and confirmed with karyotype. He was treated with Mini-CVD and Ponatinib, achieved complete remission with negative MRD by flow cytometry, however molecular studies showed BCR-ABL1 level at 58% IS indicating a persistent cytogenetic abnormality. De novo lymphoid blastic-phase CML can therefore be difficult to differentiate from Philadelphia positive B-ALL due to their overlapping clinical and laboratory picture, implying the need to do myeloid compartment evaluation at the time of diagnosis. With recent progress in the treatment of Philadelphia positive B-ALL, including the role of transplant with the use of novel agents, a better characterization of this disease entity in retrospective and prospective trials is warranted. [ABSTRACT FROM AUTHOR]

Background: This study was carried out to determine the frequency of CD34 positivity in acute lymphoblastic leukaemia (B-ALL) in our population and to report its association with the clinicopathological profile at the time of diagnosis. Methods: The cross-sectional study was conducted at National Institute of Blood Diseases and Bone Marrow Transplantation, Karachi, Pakistan, from March 2020 till December 2020.Newly diagnosed patients were selected, from both genders and all age groups. Relevant history and findings of physical examination were recorded. Immunohistochemistry was done on trephine biopsy and molecular studies were carried on bone marrow aspirates or peripheral blood samples. Results: Out of 105 patients enrolled, 67 (63.8%) were males, with a male to female ratio (M: F) 1.8:1. Of the total patients, 62 (59.04%) were above 15 years of age. CD34 was expressed in 73 (69.5%) cases. Lymphadenopathy, splenomegaly, and hepatomegaly were separately noted in context to CD 34 expression in 22 (66.6%), 24 (64.8%), and 14 (58.3%) patients, respectively. CNS disease was seen in a total of 3(2.75%) subjects, in which 2 (66.6%) of the patients had CD34 expression. Total 81 patients in our study fall into the high-risk group out of which CD 34 expression was seen in 58(71.6%) subjects. Cytogenetic analysis, BCR-ABL p190, and MLL gene rearrangement were investigated in all participants. Cytogenetic analysis revealed an abnormality in 20 (19%) cases out of which 13 (17.8%) cases were from CD34 positive group. Conclusion: Our study reported CD34 expression in more than two-thirds of cases. High-risk disease was significantly associated with CD34 expression. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML) is a myeloproliferative disease characterized by a unique BCR-ABL fusion gene. Tyrosine kinase inhibitors (TKIs) were developed to target the BCR-ABL oncoprotein, inhibiting its abnormal kinase activity. TKI treatments have significantly improved CML patient outcomes. However, the patients can develop drug resistance and relapse after therapy discontinues largely due to intratumor heterogeneity. It is critical to understand the differences in therapeutic responses among subpopulations of cells. Single-cell RNA sequencing measures the transcriptome of individual cells, allowing us to differentiate and analyze individual cell populations. Here, we integrated a single-cell RNA sequencing profile of CML stem cells and network analysis to decipher the mechanisms of distinct TKI responses. Compared to normal hematopoietic stem cells, a set of genes that were concordantly differentially expressed in various types of stem cells of CML patients was revealed. Further transcription regulatory network analysis found that most of these genes were directly controlled by one or more transcript factors and the genes have more regulators in the cells of the patients who responded to the treatment. The molecular markers including a known drug-resistance gene and novel gene signatures for treatment response were also identified. Moreover, we combined protein–protein interaction network construction with a cancer drug database and uncovered the drugs that target the marker genes directly or indirectly via the protein interactions. The gene signatures and their interacted proteins identified by this work can be used for treatment response prediction and lead to new strategies for drug resistance monitoring and prevention. Our single-cell-based findings offered novel insights into the mechanisms underlying the therapeutic response of CML. [ABSTRACT FROM AUTHOR]

Summary: Recent approval of asciminib, a novel "specifically targeting the ABL myristoyl pocket" (STAMP) BCR‐ABL1 inhibitor, for the treatment of chronic myeloid leukaemia (CML) patients who have either failed ≥2 lines of therapy or have the T315I mutation, has provided clinicians with a wider selection of potentially effective treatment options. Asciminib has the attractive twin attributes of high potency directed against BCR‐ABL1 and good tolerability based on its limited off‐target effects. However, it is unclear exactly where asciminib will be positioned amongst the other available tyrosine kinase inhibitors (TKIs), especially ponatinib which is also available for the same indications. There are many questions yet to be answered with regard to the optimal use of asciminib which include its role in the first‐ and second‐line settings, combination therapy with other TKIs, and effectiveness in advanced phase CML. In this review, we discuss the available data on asciminib while exploring a number of clinical trials in progress. Finally, we provide our opinion based on the current data about where asciminib is most likely to be the optimal choice, which will hopefully assist clinicians with therapy selection. [ABSTRACT FROM AUTHOR]

Abstract Background Imatinib is the gold standard for the treatment of all phases of Philadelphia positive Chronic Myeloid Leukemia (CML). During treatment, patients may develop cytopenia. We aimed to study the baseline characteristics and factors associated with cytopenia at a Nairobi Hospital. Methods This was a retrospective case-control study of patients aged ≥18 years on follow-up at the Glivec International Patient Access Program (GIPAP) clinic from 2007 to 2015. The cases consisted of CML patients on imatinib who developed cytopenia. The controls were CML patients on imatinib who did not develop cytopenia. Baseline socio – demographic, clinical, hematologic, and molecular data were retrieved from patients’ files. Chi square or fishers’ exact tests were used to analyze for differences between cytopenia and no cytopenia. Binary logistic regressions were employed to identify relationships. Univariate and multivariate analyses were done to identify independent predictors of cytopenia. Odds ratios (OR) were presented including the 95% confidence intervals and respective p values. Results A total of 201 patients were studied consisting of ninety-four (94) patients with cytopenia and 107 with no cytopenia. Among the entire population, males were 52, and 42% were aged 36–50 years. Sex, age, marital status, occupation and education level were similar between the cytopenia and no cytopenia groups. Among the 201 patients, 70% had symptoms for > 12 months before diagnosis, 78.6% had B symptoms at baseline, 80% had a moderate splenomegaly at baseline. Among patients with cytopenia, 40 and 37.4% developed cytopenia within 3 months and 3–6 months respectively after imatinib initiation. Baseline neutrophilia, neutropenia, anaemia, thrombocytosis, thrombocytopenia was found in 68, 11, 11, 23.5 and 11% respectively. Baseline hemoglobin, neutrophil and platelet level were significantly different between the cytopenia and the no cytopenia group. On univariable analysis, baseline anemia with hb 100,000/mm3 (p = 0.002) and thrombocytopenia (p = 0.001) increased the odds of developing cytopenia. On multivariable analysis, baseline anaemia (p value

Abstract Background Dysregulation of long noncoding RNAs (lncRNAs) has been linked to various human cancers. Bcr-Abl oncogene that results from a reciprocal translocation between human chromosome 9 and 22, is associated with several hematological malignancies. However, the role of lncRNAs in Bcr-Abl-induced leukemia remains largely unexplored. Methods LncRNA cDNA microarray was employed to identify key lncRNAs involved in Bcr-Abl-mediated cellular transformation. Abl-transformed cell survival and xenografted tumor growth in mice were evaluated to dissect the role of imatinib-upregulated lncRNA 1 (IUR1) in Abl-induced tumorigenesis. Primary bone marrow transformation and in vivo leukemia transplant using lncRNA-IUR1 knockout (KO) mice were further conducted to address the functional relevance of lncRNA-IUR1 in Abl-mediated leukemia. Transcriptome RNA-seq and Western blotting were performed to determine the mechanisms by which lncRNA-IUR1 regulates Bcr-Abl-induced tumorigenesis. Results We identified lncRNA-IUR1 as a critical negative regulator of Bcr-Abl-induced tumorigenesis. LncRNA-IUR1 expressed in a very low level in Bcr-Abl-positive cells from chronic myeloid leukemia patients. Interestingly, it was significantly induced in Abl-positive leukemic cells treated by imatinib. Depletion of lncRNA-IUR1 promoted survival of Abl-transformed human leukemic cells in experiments in vitro and xenografted tumor growth in mice, whereas ectopic expression of lncRNA-IUR1 sensitized the cells to apoptosis and suppressed tumor growth. In concert, silencing murine lncRNA-IUR1 in Abl-transformed cells accelerated cell survival and the development of leukemia in mice. Furthermore, lncRNA-IUR1 deficient mice were generated, and we observed that knockout of murine lncRNA-IUR1 facilitated Bcr-Abl-mediated primary bone marrow transformation. Moreover, animal leukemia model revealed that lncRNA-IUR1 deficiency promoted Abl-transformed cell survival and development of leukemia in mice. Mechanistically, we demonstrated that lncRNA-IUR1 suppressed Bcr-Abl-induced tumorigenesis through negatively regulating STAT5-mediated GATA3 expression. Conclusions These findings unveil an inhibitory role of lncRNA-IUR1 in Abl-mediated cellular transformation, and provide new insights into molecular mechanisms underlying Abl-induced leukemogenesis.

c-Abl, a non-receptor tyrosine kinase, regulates cell growth and survival in healthy cells and causes chronic myeloid leukemia (CML) when fused by Bcr. Its activity is blocked in the assembled inactive state, where the SH3 and SH2 domains dock into the kinase domain, reducing its conformational flexibility, resulting in the autoinhibited state. It is active in an extended ‘open’ conformation. Allostery governs the transitions between the autoinhibited and active states. Even though experiments revealed the structural hallmarks of the two states, a detailed grasp of the determinants of c-Abl autoinhibition and activation at the atomic level, which may help innovative drug discovery, is still lacking. Here, using extensive molecular dynamics simulations, we decipher exactly how these determinants regulate it. Our simulations confirm and extend experimental data that the myristoyl group serves as the switch for c-Abl inhibition/activation. Its dissociation from the kinase domain promotes the SH2-SH3 release, initiating c-Abl activation. We show that the precise SH2/N-lobe interaction is required for full activation of c-Abl. It stabilizes a catalysis-favored conformation, priming it for catalytic action. Bcr-Abl allosteric drugs elegantly mimic the endogenous myristoyl-mediated autoinhibition state of c-Abl 1b. Allosteric activating mutations shift the ensemble to the active state, blocking ATP-competitive drugs. Allosteric drugs alter the active-site conformation, shifting the ensemble to re-favor ATP-competitive drugs. Our work provides a complete mechanism of c-Abl activation and insights into critical parameters controlling at the atomic level c-Abl inactivation, leading us to propose possible strategies to counter reemergence of drug resistance.

Protein kinases are enzymes that transfer phosphate to protein, resulting in the modification of the protein. The human genome encodes approximately 538 kinases. Kinases play a role in maintaining a number of cellular processes, including control of the cell cycle, metabolism, survival, and differentiation. Protein kinase dysregulation causes several diseases, and it has been shown that numerous kinases are deregulated in cancer. The oncogenic potential of these kinases is increased by a number of processes, including overexpression, relocation, fusion point mutations, and the disruption of upstream signaling. Understanding of the mechanism or role played by kinases has led to the development of a large number of kinase inhibitors with promising clinical benefits. In this review, we discuss FDA-approved kinase inhibitors and their mechanism, clinical benefits, and side effects, as well as the challenges of overcoming some of their side effects and future prospects for new kinase inhibitor discovery.

Abstract Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm driven by BCR-ABL1 oncoprotein, which plays a pivotal role in CML pathology, diagnosis, and treatment as confirmed by the success of tyrosine kinase inhibitor (TKI) therapy. Despite advances in the development of more potent tyrosine kinase inhibitors, some mechanisms particularly in terms of CML leukemic stem cell (CML LSC) lead to intrinsic or acquired therapy resistance, relapse, and disease progression. In fact, the maintenance CML LSCs in patients who are resistance to TKI therapy indicates the role of CML LSCs in resistance to therapy through survival mechanisms that are not completely dependent on BCR-ABL activity. Targeting therapeutic approaches aim to eradicate CML LSCs through characterization and targeting genetic alteration and molecular pathways involving in CML LSC survival in a favorable leukemic microenvironment and resistance to apoptosis, with the hope of providing a functional cure. In other words, it is possible to develop the combination therapy of TKs with drugs targeting genes or molecules more specifically, which is required for survival mechanisms of CML LSCs, while sparing normal HSCs for clinical benefits along with TKIs.

Background: The BCR-ABL fusion protein is the key factor that results in the occurrence of chronic myeloid leukemia (CML). Imatinib (IM) is a targeted inhibitor of BCR-ABL to achieve complete remission. However, remission failure occurs due to acquired resistance caused by secondary BCR-ABL mutations, underlining the need for novel BCR-ABL-targeting strategies. Circular RNAs (circRNAs) derived from tumor-related genes have been revealed as possible therapeutic targets for relevant cancers in recent investigations. In CML, the roles of this kind of circRNA are yet obscure.Methods: Firstly, RT-qPCR was used for determining circCRKL expression level in cell lines and clinical samples, RNase R and Actinomycin D were employed to verify the stability of circCRKL. Then shRNAs were designed to specifically knockdown circCRKL. The function of circCRKL in vitro was investigated using CCK-8, colony formation assay, and flow cytometry, while a CML mouse model was constructed to explore the function in vivo. Finally, a dual-luciferase reporter assay, RNA pull-down, RNA immunoprecipitation, and rescue experiments were conducted to investigate the mechanism of circCRKL functioning.Results: Here, we determined circCRKL, which derives from CML-relevant gene CRKL, is over-expressed in BCR-ABL+ cells. Then we noticed knocking down circCRKL using shRNA lentivirus dampens the proliferation of BCR-ABL+ cells both in vitro and in vivo, and augments susceptibility of resistant cells to IM. Intriguingly, we observed that circCRKL has a considerable impact on the expression level of BCR-ABL. Mechanistically, circCRKL could behave like a decoy for miR-877-5p to enhance the BCR-ABL level, allowing BCR-ABL+ cells to maintain viability.Conclusions: Overall, the current study uncovers that circCRKL is specifically expressed and regulates BCR-ABL expression level via decoying miR-877-5p in BCR-ABL+ cells, highlighting that targeting circCRKL along with imatinib treatment could be utilized as a potential therapeutic strategy for CML patients. [ABSTRACT FROM AUTHOR]

Chronic myeloid leukemia (CML) is a myeloproliferative disease that mediated by BCR/ABL oncogenic signaling. CML can be targeted with the imatinib, dasatinib, and nilotinib TKI inhibitors, the latter two of them have been approved for imatinib-resistant or -intolerant CML patients. The TKIs resistance occurs by different molecular mechanisms, including overexpression of BCR-ABL, mutations in the TKI binding site of BCR/ABL, and ER-stress. Unfolded protein responses (UPR) is a cytoprotective mechanism which is activated by ER-stress. The IRE1, PERK, and ATF6 are three main arms of the UPR mechanism and are activated by a common mechanism involving the dissociation of the ER-chaperone BiP/GP78. There is a correlation between ER-stress, CML progression, and response to TKI treatment. In the present study, we aimed to determine alterations of the expression levels of genes related to UPR pathway signaling after treatment with dasatinib in K562 chronic myeloid leukemia cell line by quantitative RT-PCR relatively. The array-data revealed that treatment with dasatinib significantly decreased the UPR mechanism-related genes (including HSPA1B, HSPA2, HSPA4L, ATF6, ATF6B, CEBPB, PERK, TRIB3, DNAJB, ERN1, and UHRF1) in K562 cells. In conclusion, the results showed that dasatinib regulates the UPR mechanism that plays a significant role in cancer progression and therapy resistance in CML. Thus, dasatinib-induced dysfunction of the UPR mechanism may promise encouraging therapy for CML. [ABSTRACT FROM AUTHOR]