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Aleukemic bcr-abl positive granulocytic sarcoma

Kuan JW, Pathmanathan R, Chang KM, Tan SM

Leuk. Res., 2009 Nov;33(11):1574-7.
PMID: 19215983 DOI: 10.1016/j.leukres.2009.01.016

Granulocytic sarcoma (GS) can occur de novo or in association with intramedullary myeloid disorders. With the advent of sophisticated molecular detection techniques to detect diagnostic genes such as bcr-abl, PML-RARA and CBFB/MYH11 in bone marrow or peripheral blood, many cases of the so called 'primary' GS are questionable. We report a case of primary GS where the tumor mass bcr-abl translocation was demonstrated by fluorescent in situ hybridization in which there was no evidence of chronic myeloid leukemia (CML). This is an important finding as it highlights the possibility that CML may present as a sole extramedullary form, and illustrates potential treatment by tyrosine kinase inhibitor.

Matched MeSH terms: Genes, abl*
Fulltext Detection of bcr/abl gene in chronic myeloid leukaemia: comparison of fluorescence in situ hybridisation (fish), conventional cytogenetics and polymerase chain reaction (pcr) techniques

Siti Aishah Md Ali, Ilina Isahak, Dahlan Sabil, Fatimah Sahlan, Lokman Saim, Abdullah Sani Mohamed

Medicine & Health, 2006;1(1):5-13.
MyJurnal

The reciprocal translocation t(9;22)(q34;q11) which gives rise to the Philadelphia (Ph1) chromosome and BCR/ABL fusion gene, plays a pivotal role in the diagnosis and pathogenesis of chronic myeloid leukemia (CML). In this study, we evaluated the role of fluorescence in situ hybridisation (FISH) in detecting the BCR/ABL rearrangement in CML patients. The sensitivity, specificity and detection rate of BCR/ABL gene using FISH, PCR and conventional cytogenetics (karyotyping) methods were also compared. 18 bone marrow samples of patients with clinically diagnosed CML and suspected of CML were collected. The sensitivity, specificity and positive predictive values of FISH were altogether 100% while the sensitivity, specificity and positive predictive values for conventional cytogenetics (karyotyping) were 85%, 100% and 100% respectively. Convetional cytogenetics (karyotyping) detected an additional chromosomal aberration in addition to the Ph1 chromosome. In conclusion, FISH is a highly sensitive method in detecting the BCR/ABL gene. Conventional cytogenetics (karyotyping) remains an important investigation in the work up of suspected CML patients since there is a possibility of detecting chromosomal aberrations in addition to the Ph1 translocation. Therefore, conventional cytogenetics (karyotyping) and FISH are complementary techniques and their results should be interpreted together with clinical information.

Matched MeSH terms: Genes, abl
Silencing of suppressor of cytokine signaling-3 due to methylation results in phosphorylation of STAT3 in imatinib resistant BCR-ABL positive chronic myeloid leukemia cells

Al-Jamal HA, Jusoh SA, Yong AC, Asan JM, Hassan R, Johan MF

Asian Pac J Cancer Prev, 2014;15(11):4555-61.
PMID: 24969884

BACKGROUND: Silencing due to methylation of suppressor of cytokine signaling-3 (SOCS-3), a negative regulator gene for the JAK/STAT signaling pathway has been reported to play important roles in leukemogenesis. Imatinib mesylate is a tyrosine kinase inhibitor that specifically targets the BCR-ABL protein and induces hematological remission in patients with chronic myeloid leukemia (CML). Unfortunately, the majority of CML patients treated with imatinib develop resistance under prolonged therapy. We here investigated the methylation profile of SOCS-3 gene and its downstream effects in a BCR-ABL positive CML cells resistant to imatinib.
MATERIALS AND METHODS: BCR-ABL positive CML cells resistant to imatinib (K562-R) were developed by overexposure of K562 cell lines to the drug. Cytotoxicity was determined by MTS assays and IC50 values calculated. Apoptosis assays were performed using annexin V-FITC binding assays and analyzed by flow cytometry. Methylation profiles were investigated using methylation specific PCR and sequencing analysis of SOCS-1 and SOCS-3 genes. Gene expression was assessed by quantitative real-time PCR, and protein expression and phosphorylation of STAT1, 2 and 3 were examined by Western blotting.
RESULTS: The IC50 for imatinib on K562 was 362 nM compared to 3,952 nM for K562-R (p=0.001). Percentage of apoptotic cells in K562 increased upto 50% by increasing the concentration of imatinib, in contrast to only 20% in K562-R (p<0.001). A change from non-methylation of the SOCS-3 gene in K562 to complete methylation in K562-R was observed. Gene expression revealed down- regulation of both SOCS-1 and SOCS-3 genes in resistant cells. STAT3 was phosphorylated in K562-R but not K562.
CONCLUSIONS: Development of cells resistant to imatinib is feasible by overexposure of the drug to the cells. Activation of STAT3 protein leads to uncontrolled cell proliferation in imatinib resistant BCR-ABL due to DNA methylation of the SOCS-3 gene. Thus SOCS-3 provides a suitable candidate for mechanisms underlying the development of imatinib resistant in CML patients.

Matched MeSH terms: Genes, abl/genetics*
Fulltext Thymoquinone Induces Downregulation of BCR-ABL/JAK/STAT Pathway and Apoptosis in K562 Leukemia Cells

Al-Rawashde FA, Wan Taib WR, Ismail I, Johan MF, Al-Wajeeh AS, Al-Jamal HAN

Asian Pac J Cancer Prev, 2021 Dec 01;22(12):3959-3965.
PMID: 34967577 DOI: 10.31557/APJCP.2021.22.12.3959

OBJECTIVE: BCR ABL oncogene encodes the BCR-ABL chimeric protein, which is a constitutively activated non-receptor tyrosine kinase. The BCR-ABL oncoprotein is a key molecular basis for the pathogenesis of chronic myeloid leukemia (CML) via activation of several downstream signaling pathways including JAK/STAT pathway. Development of leukemia involves constitutive activation of signaling molecules including, JAK2, STAT3, STAT5A and STAT5B. Thymoquinone (TQ) is a bioactive constituent of Nigella sativa that has shown anticancer properties in various cancers. The present study aimed to evaluate the effect of TQ on the expression of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes and their consequences on the cell proliferation and apoptosis in K562 CML cells.
METHODS: BCR-ABL positive K562 CML cells were treated with TQ. Cytotoxicity was determined by Trypan blue exclusion assay. Apoptosis assay was performed by annexin V-FITC/PI staining assay and analyzed by flow cytometry. Transcription levels of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes were evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Protein levels of JAK2 and STAT5 were determined by Jess Assay analysis.
RESULTS: TQ markedly decreased the cell proliferation and induced apoptosis in K562 cells (P < 0.001) in a concentration dependent manner. TQ caused a significant decrease in the transcriptional levels of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes (P < 0.001). TQ induced a significant decrease in JAK2 and STAT5 protein levels (P < 0.001).
CONCLUSION: our results indicated that TQ inhibited cell growth of K562 cells via downregulation of BCR ABL/ JAK2/STAT3 and STAT5 signaling and reducing JAK2 and STAT5 protein levels.

Matched MeSH terms: Genes, abl/drug effects*