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Placental-like alkaline phosphatase (PLAP) is expressed by many tumors and can be detected in sera of patients with various cancers. Its aberrant expression has been considered to be potentially useful as tumor marker. However, the biological background of the role of this aberrant alkaline phosphatase (AP) in cancer is still unclear. The expression of various forms of AP in cells of chronic myeloid leukemia (CML) has not yet been studied., Aim: To analyze the expression patterns of various AP forms in cells originated from CML patients in blast crisis and to modify their expression by vitamin E., Materials and Methods: RNA extracted from leukemic cells was converted to cDNA and real-time reverse transcription polymerase chain reaction was performed using SYBR Green protocol with primers to tissue non-specific alkaline phosphatase (TNAP), intestinal alkaline phosphatase and CCAAT-enhancer-binding proteins alpha (C/EBPα). To analyze the modulation of expression of APs and C/EBPα, CML cells were incubated with 100 µM vitamin E., Results: We have observed the aberrant expression of mRNA intestinal alkaline phosphatase in CML cells that upon sequencing demonstrated the significant alignment with PLAP sequence while no gene homology with tissue placental alkaline phosphatase (PAP) was revealed. Vitamin E decreases mRNA PLAP expression and increases mRNA TNAP expression. Moreover, along with down-regulation of aberrant PLAP and up-regulation of TNAP, vitamin E increases C/EBPα mRNA expression., Conclusion: The loss of TNAP in CML may contribute to pathogenesis of this disease. PLAP may be considered as a putative target in differentiation therapies in myeloid neoplasms. Our findings suggest the potential role of vitamin E as the inducer of differentiation potential of leukemic cells in CML.

Background: Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder associated with the activity of BCR-ABL fusion oncogene. Tyrosine kinase inhibitors are the current treatment of CML, but secondary mutations finally contribute to therapy resistance and blast crisis of the disease. The search for the novel compounds for the effective control of CML is now in the spotlight. The progression of CML to blast crisis is correlated with down-modulation of C/EBP alpha. Therefore, C/EBP alpha may be considered as a putative target in differentiation therapies in myeloid leukemias. The aim of the study was to assess the potential of vitamin E as the possible inducer of C/EBP alpha expression in BCR-ABL-positive CML K562 cells., Materials and Methods: RNA extracted from K562 cells cultured with valproic acid or vitamin E was converted to cDNA, RT-PCR reactions were carried out using HotStarTaq DNA polymerase with primers for C/EBP alpha and granulocyte colony-stimulating factor receptor (G-CSFR)., Results: We have not found detectable expression of C/EBP alpha in K562 cells. Upon 48-h culture with vitamin E at a dose of 100 µM, K562 cells expressed both C/EBP alpha and G-CSFR., Conclusion: Vitamin E restored the expression of C/EBP alpha mRNA in chronic myelogenous leukemia K562 cells. In this setting, G-CSFR expression in vitamin E treated K562 cells seems to suggest the activation to granulocytic differentiation. It should be further elucidated whether such effects of vitamin E on C/EBP alpha transcription factor are direct or mediated indirectly due to antioxidant properties of vitamin E.

Background: DNA hypomethylation plays a key role in carcinogenesis. The malignant transformation of cells as well as tumor progression is accompanied with increasing DNA hypomethylation in cancer cells. Nevertheless, the evolution of dis-epigenetic genomic alteration in the somatic cellular malignant transformation has not yet been clear., Aim: To study the relationship between the pattern of genomic DNA hypomethylation and DNA hyperploidy., Methods: The model of 5-azacytidine demethylating DNA treatment of the mitogen-stimulated lymphocytes in parallel with patients with solid cancer has been explored. DNA content was measured by quantitative DAPI and Hoechst 33258 fluorescence in situ hybridization on interphase nuclei. The conventional mitogen-stimulated blood lymphocyte culture development was performed in metaphase chromosomes and interphase nuclei assay. The light and fluorescent cytomorphological microscopy was performed., Results: The model 5-azacytidine induced DNA demethylation results in increased DNA hyperploidy accompanying major pericentromeric heterochromatin (Alu) DNA repeats amplification similar to those during DNA hypomethylation-associated cancer events, and both contributed to nuclear heteropycnosis development. The constitutive pericentromeric heterochromatin consequent morphological disturbance to the latent polytene chromomerization and heteropycnosis development both in cancer patients and in model 5-azacytidine exposured lymphocytes are associated with DNA hypomethylation., Conclusion: We have observed that the induced global DNA hypomethylation triggers dis-epigenetic morphological reprogramming of constitutive pericentromeric heterochromatin on the extrachromosomal organization pathway as seen during the heterochromatin latent polytene features development, which is of importance as one of the mechanism involving DNA hypomethylation in initiation and progression of cancer.