• BMB Reports
• /
• v.56 no.2
• /
• pp.78-83
• /
• 2023

Chronic myeloid leukemia (CML) has a markedly improved prognosis with the use of breakpoint cluster region-abelson 1 (BCR-ABL1) tyrosine kinase inhibitors (BCR-ABL1 TKIs). However, approximately 40% of patients are resistant or intolerant to BCR-ABL1 TKIs. Hypoxia-inducible factor 1α (HIF-1α) is a hypoxia response factor that has been reported to be highly expressed in CML patients, making it a therapeutic target for BCR-ABL1 TKI-sensitive CML and BCR-ABL1 TKI-resistant CML. In this study, we examined whether HIF-1α inhibitors induce cell death in CML cells and BCR-ABL1 TKI-resistant CML cells. We found that echinomycin and PX-478 induced cell death in BCR-ABL1 TKIs sensitive and resistant CML cells at similar concentrations while the cell sensitivity was not affected with imatinib or dasatinib in BCR-ABL1 TKIs resistant CML cells. In addition, echinomycin and PX-478 inhibited the c-Jun N-terminal kinase (JNK), Akt, and extracellular-regulated protein kinase 1/2 (ERK1/2) activation via suppression of BCR-ABL1 and Met expression in BCR-ABL1 sensitive and resistant CML cells. Moreover, treatment with HIF-1α siRNA induced cell death by inhibiting BCR-ABL1 and Met expression and activation of JNK, Akt, and ERK1/2 in BCR-ABL1 TKIs sensitive and resistant CML cells. These results indicated that HIF-1α regulates BCR-ABL and Met expression and is involved in cell survival in CML cells, suggesting that HIF-1α inhibitors induce cell death in BCR-ABL1 TKIs sensitive and resistant CML cells and therefore HIF-1α inhibitors are potential candidates for CML treatment.

• Clinical and Experimental Vaccine Research
• /
• v.12 no.4
• /
• pp.319-327
• /
• 2023

Purpose: Patients with hematological malignancies are at an increased risk of severe infection with coronavirus disease 2019 (COVID-19). However, developing an adequate immune response after vaccination is difficult, especially in patients with lymphoid neoplasms. Since the long-term effects of the BNT162b2 vaccine are unclear, the humoral immune response 5 months after the two vaccinations in patients with hematological disorders was analyzed. Materials and Methods: Samples were collected from 96 patients vaccinated twice with BNT162b2 and treated with at least one line of an antitumor or immunosuppressive drug in our hospital from November 2021 to February 2022. Serum anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) spike (S) antibody titers were analyzed. Patients were age- and sex-matched using propensity matching and compared with a healthy control group. Patients with serum anti-SARS-CoV-2 S antibodies were defined as 'responder' if >50 U/mL. The patients had B-cell non-Hodgkin lymphoma (B-NHL), multiple myeloma, chronic myeloid leukemia, etc. Results: Patients had significantly low antibody levels (median, 55.3 U/mL vs. 809.8 U/mL; p<0.001) and a significantly low response rate (p<0.001). Multivariate analysis showed that patients with B-NHL, aged >72 years, were associated with a low response to vaccination. There were no significant differences between patients with chronic myeloid leukemia and healthy controls. Conclusion: Our study shows that patients with hematological disorders are at risk of developing severe COVID-19 infections because of low responsiveness to vaccination. Moreover, the rate of antibody positivity differed between the disease groups. Further studies are warranted to determine an appropriate preventive method for these patients, especially those with B-NHL.

• Biomolecules & Therapeutics
• /
• v.32 no.5
• /
• pp.582-600
• /
• 2024

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment landscape for chronic myeloid leukemia (CML). However, TKI resistance poses a significant challenge, leading to treatment failure and disease progression. Resistance mechanisms include both BCR::ABL1-dependent and BCR::ABL1-independent pathways. The mechanisms underlying BCR::ABL1 independence remain incompletely understood, with CML cells potentially activating alternative signaling pathways, including the AKT/mTOR and JAK2/STAT5 pathways, to compensate for the loss of BCR::ABL1 kinase activity. This study explored tumoral VISTA (encoded by VSIR) as a contributing factor to TKI resistance in CML patients and identified elevated tumoral VISTA levels as a marker of resistance and poor survival. Through in vitro and in vivo analyses, we demonstrated that VSIR knockdown and the application of NSC-622608, a novel VISTA inhibitor, significantly impeded CML cell proliferation and induced apoptosis by attenuating the AKT/mTOR and JAK2/STAT5 pathways, which are crucial for CML cell survival independent of BCR::ABL1 kinase activity. Moreover, VSIR overexpression promoted TKI resistance in CML cells. Importantly, the synergistic effect of NSC-622608 with TKIs offers a potent therapeutic avenue against both imatinib-sensitive and imatinib-resistant CML cells, including those harboring the challenging T315I mutation. Our findings highlight the role of tumoral VISTA in mediating TKI resistance in CML, suggesting that inhibition of VISTA, particularly in combination with TKIs, is an innovative approach to enhancing treatment outcomes in CML patients, irrespective of BCR::ABL1 mutation status. This study not only identified a new pathway contributing to TKI resistance but also revealed the possibility of targeting tumoral VISTA as a means of overcoming this significant clinical challenge.

• BMB Reports
• /
• v.44 no.9
• /
• pp.601-606
• /
• 2011

HMGB1 is associated with human cancers and is an activator of autophagy which mediates chemotherapy resistance. We here show that the mRNA levels of HMGB1 are high in leukemia cells and it is involved in the progression of childhood chronic myeloid leukemia (CML). HMGB1 decreases the sensitivity of human myeloid leukemia cells K562 to anti-cancer drug induced death through up-regulating the autophagy pathway, which is confirmed by the observation with an increase in fusion of autophagosomes and autophagolysosomes. When overexpressing HMGB1, both mRNA levels of Beclin-1, VSP34 and UVRAG which are key genes involved in mammalian autophagy and protein levels of p-Bcl-2 and LC3-II are increased. Luciferase assays document that over-expression of HMGB1 increases the transcriptional activity of JNK and ERK, which may be silenced by siRNA. The results suggest that HMGB1 regulates JNK and ERK required for autophagy, which provides a potential drug target for therapeutic interventions in childhood CML.

• Tuberculosis and Respiratory Diseases
• /
• v.71 no.3
• /
• pp.210-215
• /
• 2011

Imatinib mesylate, a selective inhibitor of BCR-ABL kinase activity, has demonstrated significant clinical efficacy in the treatment of chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs). It has become the standard of treatment for these diseases. Although the toxicity profile of imatinib is superior to that of interferon or other cytotoxic agents, some adverse events including edema, gastrointestinal toxicities and hematologic toxicities are commonly observed in the patients treated by imatinib. We present two cases of imatinib induced interstitial pneumonitis during the treatment of a chronic phase of CML.

• Journal of Oral Medicine and Pain
• /
• v.42 no.2
• /
• pp.49-52
• /
• 2017

Leukemia is a malignant disease characterized by uncontrolled clonal proliferation of white blood cells. It is classified depending on clinical course of disease (acute or chronic) and the primary hematopoietic cell line affected (myeloid or lymphoid). Leukemia is often associated with orofacial manifestations, such as oral bleeding, petechiae, oral ulceration, gingival enlargement, mucosal pallor and mental nerve neuropathy. However, trismus has been rarely reported as a sign of leukemia. We present a case of trismus caused by acute lymphoblastic leukemia and emphasize the importance of orofacial manifestations in the early diagnosis of leukemia.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.2
• /
• pp.677-684
• /
• 2016

Background: Acute lymphoblastic leukemia (ALL) is a heterogeneous disease which requires a risk-stratified approach for appropriate treatment. Specific chromosomal translocations within leukemic blasts are important prognostic factors that allow identification of relevant subgroups. In this study, we developed a multiplex RT-PCR assay for detection of the 4 most frequent translocations in ALL (BCR-ABL, TEL-AML1, MLL-AF4, and E2A-PBX1). Materials and Methods: A total of 214 diagnosed ALL samples from both adult and pediatric ALL and 14 cases of CML patients (154 bone marrow and 74 peripheral blood samples) were assessed for specific chromosomal translocations by cytogenetic and multiplex RT-PCR assays. Results: The results showed that 46 cases of ALL and CML (20.2%) contained the fusion transcripts. Within the positive ALL patients, the most prevalent cryptic translocation observed was mBCR-ABL (p190) at 8.41%. In addition, other genetic rearrangements detected by the multiplex PCR were 4.21% TEL-AML1 and 2.34% E2A-PBX1, whereas MLL-AF4 exhibited negative results in all tested samples. Moreover, MBCR-ABL was detected in all 14 CML samples. In 16 samples of normal karyotype ALL (n=9), ALL with no cytogentic result (n=4) and CML with no Philadelphia chromosome (n=3), fusion transcripts were detected. Conclusions: Multiplex RT-PCR provides a rapid, simple and highly sensitive method to detect fusion transcripts for prognostic and risk stratification of ALL and CML patients.

• Molecules and Cells
• /
• v.44 no.7
• /
• pp.444-457
• /
• 2021

Although the mechanism of chronic myeloid leukemia (CML) initiation through BCR/ABL oncogene has been well characterized, CML cell differentiation into erythroid lineage cells remains poorly understood. Using CRISPR-Cas9 screening, we identify Chromobox 8 (CBX8) as a negative regulator of K562 cell differentiation into erythrocytes. CBX8 is degraded via proteasomal pathway during K562 cell differentiation, which activates the expression of erythroid differentiation-related genes that are repressed by CBX8 in the complex of PRC1. During the differentiation process, the serine/threonine-protein kinase PIM1 phosphorylates serine 196 on CBX8, which contributes to CBX8 reduction. When CD235A expression levels are analyzed, the result reveals that the knockdown of PIM1 inhibits K562 cell differentiation. We also identify TRIM28 as another interaction partner of CBX8 by proteomic analysis. Intriguingly, TRIM28 maintains protein stability of CBX8 and TRIM28 loss significantly induces proteasomal degradation of CBX8, resulting in an acceleration of erythroid differentiation. Here, we demonstrate the involvement of the CBX8-TRIM28 axis during CML cell differentiation, suggesting that CBX8 and TRIM28 are promising novel targets for CML research.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.12
• /
• pp.7501-7508
• /
• 2013

Background: Chronic myeloid leukemia (CML) is a myeloproliferative disorder of hematopoietic stem cell scarrying the Philadelphia (Ph) chromosome and an oncogenic BCR-ABL1 fusion gene. The tyrosine kinase inhibitor (TKI) of BCR-ABL1 kinase is a treatment of choice for control of CML. Objective: Recent studies have demonstrated that miRNAs within exosomes from cancer cells play crucial roles in initiation and progression. This study was performed to assess miRNAs within exosomes of K562 cells. Methods: miRNA microarray analysis of K562 cells and K562 cell-derived exosomes was conducted with the 6th generation miRCURYTM LNA Array (v.16.0). Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were also carried out. GO terms and signaling pathways were categorized into 66 classes (including homophilic cell adhesion, negative regulation of apoptotic process, cell adhesion) and 26 signaling pathways (such as Wnt). Results: In exosomes, 49 miRNAs were up regulated as compared to K562 cells, and two of them were further confirmed by quantitative real-time PCR. There are differentially expressed miRNAs between K562 cell derived-exosomes and K562 cells. Conclusion: Selectively expressed miRNAs in exosomes may promote the development of CML via effects on interactions (e.g. adhesion) of CML cells with their microenvironment.

• Tuberculosis and Respiratory Diseases
• /
• v.75 no.6
• /
• pp.256-259
• /
• 2013

Imatinib mesylate is a targeted therapy that acts by inhibiting tyrosine kinase of the bcr-abl fusion oncoprotein, which is specific to chronic myeloid leukemia (CML), and the c-transmembrane receptor, which is specific to gastrointestinal stromal tumors. Interstitial pneumonitis is a rare adverse event of imatinib therapy. It is clinically difficult to distinguish from infectious pneumonia, which can frequently occur due to the underlying disease. The standard treatment for imatinib-induced pneumonitis is to discontinue the medication and optionally administer corticosteroids. However, there are a few cases of successful retrial with imatinib. We describe a case of successful rechallenge of imatinib in a patient with imatinib-induced interstitial pneumonitis and CML without a recurrence of the underlying disease after 3 months of follow-up.