Current perspectives for the treatment of chronic myeloid leukemia

siRNA-mediated downregulation of BATF3 diminished proliferation and induced apoptosis through downregulating c-Myc expression in chronic myelogenous leukemia cells

OBJECTIVE

Despite considerable improvement in therapeutic approaches to chronic myeloid leukemia (CML) treatment, this malignancy is considered incurable due to resistance. However, investigating the molecular mechanism of CML may give rise to the development of extremely efficient targeted therapies that improve the prognosis of patients. Basic leucine zipper transcription factor ATF-like3 (BATF3), as transcription factor, is considered a key regulator of cellular activities and its function has been evaluated in tumor development and growth in several cancer types. This study aimed to evaluate the potential of the cellular impact of siRNA-mediated downregulation of BATF3 on CML cancer cells through cell proliferation, induction of apoptosis, and cell cycle distribution.

MATERIALS AND METHODS

The transfection of BATF3 siRNA to K562 CML cells was performed by electroporation device. To measure cellular viability and apoptosis, MTT assay and Annexin V/PI staining were carried out, respectively. Also, cell cycle assay and flow cytometry instrument were applied to assess cell cycle distribution of K562 cells. For more validation, mRNA expression of correlated genes was relatively evaluated by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The data indicated that siRNA-mediated BATF3 inactivating severely promoted the cell apoptosis. Also, the targeted therapy led to high expression of Caspase-3 gene and Bax/Bcl-2 ratio. Silenced BATF3 also induced cell cycle arrest in phase sub-G1 compared to control. Finally, a noticeable decrement was obtained in c-Myc gene expression through suppression of BATF3 in CML cells.

CONCLUSION

The findings of this research illustrated the suppression of BATF3 as an effective targeted therapy strategy for CML.

Effects of berberine on leukemia with a focus on its molecular targets

Leukemia is a common cancer among both women and men worldwide. Besides the fact that finding new treatment methods may enhance the life quality of patients, there are several problems that we face today in treating leukemia patients, such as drugs side effects and acquired resistance to chemotherapeutic drugs. Berberine is a bioactive alkaloid found in herbal plants (e.g. Rhizoma coptidis and Cortex phellodendri) and exerts several beneficial functions, including anti-tumor activities. Furthermore, berberine exerts antiproliferative and anti-inflammatory effects. Up to now, some studies have investigated the roles of berberine in different types of leukemia, including acute myeloid leukemia and chronic lymphocytic leukemia. In this review, a detailed description of berberine roles in leukemia is provided. We discuss how berberine involves different molecular targets (e.g. interleukins and cyclins) and signaling pathways (e.g. mTOR and PI3K) to exert its anti-tumor functions and how berberine is effective in leukemia treatment when combined with other therapeutic drugs.

Bowel Perforation Secondary to Ponatinib Treatment in a Chronic Myelogenous Leukemia Patient: A Case Report

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm of hematopoietic cell origin.It arises from the translocation of chromosomes 9 and 22, with resultant Philadelphia (Ph⁺) chromosome that contains the BCR-ABL1 gene. CML has three phases: the chronic phase, the accelerated phase, and blast crisis. Tyrosine kinase inhibitors are used as the targeted therapy of CML. This report is about a 30-year-old male who is normally fit and well with no past medical history of note. He was diagnosed previously with CML and presented in a blast crisis. With this blast crisis at presentation, the patient was started on ponatinib. After 12 days from starting ponatinib, the patient presented with abdominal pain and vomiting. Imaging showed small bowel perforation, which required immediate surgery. The patient’s cardiovascular risk for such event was low and ponatinib was thought to be the most likely cause of this complication; thus, higher-risk patients for such ischemic events should be observed closely.

Tyrosine kinase inhibitor resistance: a case report on chronic myeloid leukemia and Gilbert's syndrome

Although tyrosine kinase inhibitors (TKI) are commonly used as targeted treatment options for chronic myeloid leukemia (CML), its use is associated to UGT1A1 polymorphisms and, consequently, are related to a higher risk of manifesting Gilbert's syndrome, a genetic disorder associated to hyperbilirubinemia. The report of concomitant condition of CML and Gilbert's Syndrome is uncommon. Therefore, the aim of this study was to report the clinical case of a patient diagnosed with CML and subsequently, with Gilbert's Syndrome. A 34-year-old female was diagnosed with CML. On physical examination, spleen and liver were palpable, indicating hepatosplenomegaly. Laboratory findings of peripheral blood showed leukocytosis (165,190/mm³), 6% of blasts and a bone marrow biopsy showed hypercellularity by granulocytic series with moderate maturation delay. After diagnosis, the patient immediately started chemotherapy with the TKI Imatinib. One year after treatment, due to the partial response, the therapy was changed to Nilotinib, resulting in a complete response. Despite the absence of hyperbilirubinemia, a genetic study by polymerase chain reaction (PCR) verified a positivity for Gilbert's Syndrome. TKIs are also inhibitors of the enzyme UDPGT1, leading to deficient glucuronidation, causing manifestation of Gilbert's Syndrome. This report demonstrates the case of a patient that, besides having two coexisting conditions that could cause hyperbilirubinemia, did not have bilirubin alterations and it highlights the importance of having genetic investigations in cancer patients, in order to identify secondary diseases that could worsen the course of treatment.

Four-Dimensional Echocardiographic Evaluation of Left Ventricular Systolic Functions in Patients with Chronic Myeloid Leukaemia Receiving Tyrosine Kinase Inhibitors

Tyrosine kinase inhibitors (TKIs) are established treatment for haematological malignancies. However, cardiac adverse effects, including the reduction in left ventricular ejection fraction and symptomatic heart failure remain clinical problems. The purpose of this study was to evaluate the left ventricular systolic functions in patients with chronic myeloid leukaemia receiving TKIs. A cross-sectional and observational study was conducted of 37 patients with chronic myeloid leukaemia receiving dasatinib or nilotinib after imatinib failure. Left ventricular systolic functions were evaluated using four-dimensional speckle tracking echocardiography derived global longitudinal (GLS), circumferential (GCS), radial (GRS), and area (GAS) strain indices. Mean ejection fraction, stroke volume, cardiac output and left ventricular mass index were similar between control and patient groups and within normal limits. GLS (- 16.7% vs - 20.8%, p < 0.001), GCS (- 13.0% vs - 15.6%, p = 0.002), and GAS (- 26.2% vs - 31.0, p < 0.001) values were significantly higher in the patient population than those of the controls. Dasatinib and nilotinib groups did not show differences regarding strain indices. In multivariate regression analysis, only the usage of dasatinib or nilotinib was found to be an independent risk factor for diminished GAS (β = 4.406, p = 0.016), GLS (β = 3.797, p = 0.001), and GCS (β = 2.404, p = 0.040). Although imatinib, nilotinib, and dasatinib seem to be clinically safe in terms of cardiac function, monitoring of systolic functions using strain imaging, and long-term observation of patients may provide early detection of the possible cardiac toxicity.

Aberrant DNA methylation of PTPRG as one possible mechanism of its under-expression in CML patients in the State of Qatar

Background

Several studies showed that aberrant DNA methylation is involved in leukemia and cancer pathogenesis. Protein tyrosine phosphatase receptor gamma (PTPRG) expression is a natural inhibitory mechanism that is downregulated in chronic myeloid leukemia (CML) disease. The mechanism behind its downregulation has not been fully elucidated yet.

Aim

This study aimed to investigate the CpG methylation status at the PTPRG locus in CML patients.

Methods

Peripheral blood samples from CML patients at time of diagnosis [no tyrosine kinase inhibitors (TKIs)] (n = 13), failure to (TKIs) treatment (n = 13) and healthy controls (n = 6) were collected. DNA was extracted and treated with bisulfite treatment, followed by PCR, sequencing of 25 CpG sites in the promoter region and 26 CpG sites in intron‐1 region of PTPRG. The bisulfite sequencing technique was employed as a high‐resolution method.

Results

CML groups (new diagnosed and failed treatment) showed significantly higher methylation levels in the promoter and intron‐1 regions of PTPRG compared to the healthy group. There were also significant differences in methylation levels of CpG sites in the promoter and intron‐1 regions amongst the groups.

Conclusion

Aberrant methylation of PTPRG is potentially one of the possible mechanisms of PTPRG downregulation detected in CML.

Insulin-like growth factor-binding proteins play a significant role in the molecular response to imatinib in chronic myeloid leukemia patients

Imatinib (IM) is successfully used in the majority of patients with chronic myeloid leukemia (CML), but some patients develop resistance to drug treatment. Insufficient apoptosis results in uncontrolled cell proliferation, which is closely associated with the occurrence of drug resistance. Therefore, it is crucial to identify new biomarkers related to drug resistance. This aim of the present study was to investigate the profile of apoptosis-related proteins in K562 and K562/G (IM-resistant K562 cells) cells, in order to identify new biomarkers. A human apoptosis antibody array was used to screen 46 proteins in the two cells lines, among which 20 proteins were found to be differentially expressed between K562 and K562/G cells. The major proteins included secreted caspase-8, insulin-like growth factor-binding protein (IGFBP)-1, IGFBP-2, IGFBP-3, caspase-3 and p27. IGFBP-1 IGFBP-2 and IGFBP-3 were selected for the follow-up study. Subsequently, reverse transcription-quantitative PCR analysis and western blotting were used to detect the expression levels of the IGFBPs. The results revealed that the expression levels of IGFBP-2 and IGFBP-3 in K562/G cells were significantly decreased compared with those in K562 cells, whereas the IGFBP-1 level was higher. Moreover, no significant correlation was observed between IGFBP-1 or IGFBP-2 and the level of the BCR-ABL fusion protein, whereas decreasing IGFBP-3 levels were associated with increasing BCR-ABL levels. These results suggested that IGFBP-1, IGFBP-2 and IGFBP-3 could be useful novel biomarkers for IM resistance in CML.

WHO 2016 Definition of Chronic Myeloid Leukemia and Tyrosine Kinase Inhibitors

Philadelphia (Ph*)/BCR-ABL1-positive chronic myeloid leukemia (CML) is considered as a chronic life-long disease, which could be manageable with tyrosine kinase inhibitor (TKI) drugs. The aim of TKI drug treatment is to provide age- and sex-matched duration of life in a given patient with CML. Personalized CML treatment with TKI drugs is the key strategy. Individual treatment approach includes the harmonization of CML disease characteristics, clinical experience, and best available clinical evidence. Specific CML disease characteristics in a given patient include; CML disease risk, comorbidities, molecular profile, compliance, lifestyle, and drug off-target risk profile. CML research evidence includes; randomized clinical trials indicating the data on the efficacy, safety, tolerability, toxicity, possible long-term adverse events, and pharmacoeconomy of TKIs. Clinical and physician experience includes TKI availability, TKI reimbursability, drug experience, adherence, and BCR-ABL1 monitorization facilities. The key decision of choosing a TKI of choosing TKIs for CML should be made via the consideration of these variables. The aim of this paper is to outline the latest 2016 World Health Organization definition of CML and its proper management with TKI-class drugs.

Beyond TCR Signaling: Emerging Functions of Lck in Cancer and Immunotherapy

In recent years, the lymphocyte-specific protein tyrosine kinase (Lck) has emerged as one of the key molecules regulating T-cell functions. Studies using Lck knock-out mice or Lck-deficient T-cell lines have shown that Lck regulates the initiation of TCR signaling, T-cell development, and T-cell homeostasis. Because of the crucial role of Lck in T-cell responses, strategies have been employed to redirect Lck activity to improve the efficacy of chimeric antigen receptors (CARs) and to potentiate T-cell responses in cancer immunotherapy. In addition to the well-studied role of Lck in T cells, evidence has been accumulated suggesting that Lck is also expressed in the brain and in tumor cells, where it actively takes part in signaling processes regulating cellular functions like proliferation, survival and memory. Therefore, Lck has emerged as a novel druggable target molecule for the treatment of cancer and neuronal diseases. In this review, we will focus on these new functions of Lck.