ABSTRACT
Background@#Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in children.Several environmental and genetic factors are known to be involved in its development and progression. The angiopoietin-Tie system is one of the most critical factors in angiogenesis, and its possible role in solid tumors and leukemia has been previously investigated. In this study, we examined the expression of these genes in ALL patients (early pre-B-ALL and pre-B-ALL) and compared them with normal samples. @*Methods@#Bone marrow samples were collected from 40 patients (aged 0‒19 yr) newly diagnosed with early pre-B-ALL or pre-B-ALL using molecular and flow cytometric tests and from 15 control individuals. For molecular tests, RNA extraction and cDNA synthesis were performed, and Ang1, Ang2, Ang4, Tie1, and Tie2 gene expression was examined by real-time polymerase chain reaction. @*Results@#Ang2, Tie1, and Tie2 gene expression were significantly increased in patients with ALL, whereas Ang1 gene expression was decreased. The Ang4 gene did not show significant expression changes between the two groups. @*Conclusion@#Changes in the expression of the Ang-Tie system indicate a possible role of angiogenesis in ALL prognosis. Moreover, such changes can be considered as potential diagnostic biomarkers or therapeutic targets.
ABSTRACT
Background@#Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in children.Several environmental and genetic factors are known to be involved in its development and progression. The angiopoietin-Tie system is one of the most critical factors in angiogenesis, and its possible role in solid tumors and leukemia has been previously investigated. In this study, we examined the expression of these genes in ALL patients (early pre-B-ALL and pre-B-ALL) and compared them with normal samples. @*Methods@#Bone marrow samples were collected from 40 patients (aged 0‒19 yr) newly diagnosed with early pre-B-ALL or pre-B-ALL using molecular and flow cytometric tests and from 15 control individuals. For molecular tests, RNA extraction and cDNA synthesis were performed, and Ang1, Ang2, Ang4, Tie1, and Tie2 gene expression was examined by real-time polymerase chain reaction. @*Results@#Ang2, Tie1, and Tie2 gene expression were significantly increased in patients with ALL, whereas Ang1 gene expression was decreased. The Ang4 gene did not show significant expression changes between the two groups. @*Conclusion@#Changes in the expression of the Ang-Tie system indicate a possible role of angiogenesis in ALL prognosis. Moreover, such changes can be considered as potential diagnostic biomarkers or therapeutic targets.
ABSTRACT
BACKGROUND: Ikaros family zinc finger 1 (IKZF1) is a transcription factor with an important role in controlling hematopoietic proliferation and function, particularly lymphoid cell differentiation. It was previously shown that various mechanisms and expression patterns of Ikaros are linked to a variety of cancers. We hypothesized that aberrant methylation (hypomethylation) of the IKZF1 promoter region might be one of the causes of B-cell acute lymphoblastic leukemia (B-ALL). In B-ALL patients, an increased expression of this gene is a potential cause of B-cell differentiation arrest and proliferation induction. Therefore, as more than 90% of patients with ALL are <15 years old, we investigated the methylation pattern of the IKZF1 promoter in childhood B-ALL. METHODS: Twenty-five newly diagnosed B-ALL cases were included (all younger than 15 yr). In addition, we selected 25 healthy age- and sex-matched children as the control group. We collected the blood samples in EDTA-containing tubes and isolated lymphocytes from whole blood using Ficoll 1.077 Lymphosep. Next, we extracted genomic DNA with the phenol/chloroform method. Two microgram of DNA per sample was treated with sodium bisulfite using the EpiTect Bisulfite Kit, followed by an assessment of DNA methylation by polymerase chain reaction (PCR) analysis of the bisulfite-modified genomic DNA. RESULTS: Our data highlighted a hypomethylated status of the IKZF1 promoter in the ALL cases (96% of the cases were unmethylated). In contrast, the control group samples were partially methylated (68%). CONCLUSION: This study demonstrated a hypomethylated pattern of the IKZF1 promoter region in childhood B-ALL, which might underlie the aberrant Ikaros expression patterns that were previously linked to this malignancy.
Subject(s)
Child , Humans , B-Lymphocytes , DNA , DNA Methylation , Ficoll , Hematologic Neoplasms , Leukemia , Lymphocytes , Methods , Methylation , Polymerase Chain Reaction , Precursor Cell Lymphoblastic Leukemia-Lymphoma , Promoter Regions, Genetic , Sodium , Transcription Factors , Zinc FingersABSTRACT
Background: One of the most significant problems in the treatment of leukemia is the expansion of resistance to chemotherapeutic agents. Therefore, assessing the drug resistance and especially the drug resistance genes of leukemic cells is important in any treatment. The impact of Mesenchymal Stem Cells [MSCs] and hypoxic condition have been observed in the biological performance of majority of leukemic cells
Methods: MOLT-4 cells were co-cultured with MSCs in the hypoxic condition induced by Cobalt Chloride [CoCl2] for 6 and 24 hr. Then, apoptosis of cells was analyzed using annexin-V/PI staining and expression of the drug resistance genes including MDR1, MRP, and BCRP along with apoptotic and anti-apoptotic genes, including BAX and BCL2, was evaluated by real-time PCR
Results: The hypoxic condition for MOLT-4 cells co-cultured with MSCs could significantly increase the expression of MDR1 and BCRP genes [p<0.05] which are involved in drug resistance. Also, the results indicated that this condition significantly increases the expression of BCL2 [p<0.05] and reduces the apoptosis in MOLT- 4 cells co-cultured with MSCs in the hypoxic condition
Conclusions: These effects can demonstrate the important role of hypoxia and MSCs on the biological behavior of Acute Lymphoblastic Leukemia [ALL] cells that may lead to particular treatment outcomes
ABSTRACT
Objective: DNA methylation is a well-studied epigenetic mechanism that is a potent arm of the gene expression controlling machinery. Since the hypoxic situation and the various cells of bone marrow microenvironment, e.g. mesenchymal stem cells, play a role in the in vivo and in vitro biology of leukemic cells, we decided to study the effects of hypoxia and mesenchymal stem cells [MSCs] on the promoter methylation pattern of BAX and BCL2 genes
Materials and Methods: In this experimental study, the co-culture of MOLT-4 cells with MSCs and treatment with CoCl2 was done during 6, 12, and 24 hour periods. Total DNA was extracted using commercial DNA extraction kits, and sodium bisulfite [SBS] treatment was performed on the extracted DNA. Methylation specific polymerase chain reaction [MSP] was used to evaluate the methylation status of the selected genes' promoter regions
Results: The BAX and BCL2 promoters of untreated MOLT-4 cells were in partial methylated and fully unmethylated states, respectively. After incubating the cancer cells with CoCl2and MSCs, the MSP results after 6, 12, and 24 hours were the same as untreated MOLT-4 cells. In other words, the exposure of MOLT-4 cells to the hypoxia-mimicry agent and MSCs in various modes and different time frames showed that these factors have exerted no change on the methylation signature of the studied fragments from the promoter region of the mentioned genes
Conclusion: Hypoxia and MSCs actually have no notable effect on the methylation status of the promoters of BAX and BCL2 in the specifically studied regions. DNA methylation is probably not the main process by which MSCs and CoCl2 induced hypoxia regulate the expression of these genes. Finally, we are still far from discovering the exact functional mechanisms of gene expression directors, but these investigations can provide new insights into this field for upcoming studies