Roles of ten-eleven translocation family proteins and their O-linked ß-N-acetylglucosaminylated forms in cancer development.

Members of the ten-eleven translocation (TET) protein family of which three mammalian TET proteins have been discovered so far, catalyze the sequential oxidation of 5-methylcytosine to 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine which serve an important role in embryonic development and tumor progression. O-GlcNAcylation (O-linked ß-N-acetylglucosaminylation) is a reversible post-translational modification known to serve important roles in tumorigenesis and metastasis especially in hematopoietic malignancies such as myelodysplastic syndromes, chronic myelomonocytic leukemia and acute myeloid leukemia. O-GlcNAcylation activity requires only two enzymes: O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). OGT catalyzes attachment of GlcNAc sugar to serine, threonine and cytosine residues in proteins, while OGA hydrolyzes O-GlcNAc attached to proteins. Numerous recent studies have demonstrated that TETs can be O-GlcNAcylated by OGT, with consequent alteration of TET activity and stability. The present review focuses on the cellular, biological and biochemical functions of TET and its O-GlcNAcylated form and proposes a model of the role of TET/OGT complex in regulation of target proteins during cancer development. In addition, the present review provides directions for future research in this area.

[Effect of B4GALT1 on Proliferation of Its Co-cultured Human Acute Myeloid Leukemia Cell Line in Bone Marrow Stromal Cells].

OBJECTIVE: To investigate the effect of bone marrow stromal cell glycosyltransferase B4GALT1 expression on hematopoietic cell proliferation and its upstream regulation mechanism. METHODS: B4GALT1 was overexpressed in human bone marrow stromal cell line HS5, which was then co-cultured with acute myeloid leukemia cell line KG1a. And its effect on hematopoietic cell proliferation was detected by flow cytometry. Dual luciferase reporter assay, real-time PCR and Western blot were used to predict and validate upstream transcription factors that regulate stromal cell B4GALT1 expression. RESULTS: Overexpression of B4GALT1 in HS5 significantly promoted the proliferation of KG1a in the co-culture system. B4GALT1 expression in stromal cells positively correlated with upstream c-Jun expression, which was verified by JNK/c-Jun inhibitors. CONCLUSION: The differential expression of glycosyltransferases and their corresponding glycosylation in the hematopoietic microenvironment play an important role.