GALNT11 as a new molecular marker in chronic lymphocytic leukemia.
Aberrant mucin O-glycosylation often occurs in different cancers and is characterized by immature expression of simple mucin-type carbohydrates. At present, there are some controversial reports about the Tn antigen (GalNAcα-O-Ser/Thr) expression and there is a great lack of information about the [UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-Ts)] expression in chronic lymphocytic leukemia (CLL). To gain insight in these issues we evaluated the Tn antigen expression in CLL patient samples using two Tn binding proteins with different fine specificity. We also studied the expression from 14 GalNAc-Ts genes in CLL patients by RT-PCR. Our results have provided additional information about the expression level of the Tn antigen, suggesting that a low density of Tn residues is expressed in CLL cells. We also found that GALNT11 was expressed in CLL cells and normal T cell whereas little or no expression was found in normal B cells. Based on these results, GALNT11 expression was assessed by qPCR in a cohort of 50 CLL patients. We found significant over-expression of GALNT11 in 96% of B-CLL cells when compared to normal B cells. Moreover, we confirmed the expression of this enzyme at the protein level. Finally we found that GALNT11 expression was significantly associated with the mutational status of the immunoglobulin heavy chain variable region (IGHV), [א(2)(1)=18.26; P<0.0001], lipoprotein lipase expression [א(2)(1)=13.72; P=0.0002] and disease prognosis [א(2)(1)=15.49; P<0.0001]. Our evidence suggests that CLL patient samples harbor aberrant O-glycosylation highlighted by Tn antigen expression and that the over-expression of GALNT11 constitutes a new molecular marker for CLL.
Molecular Biology Unit, Institut Pasteur de Montevideo, Montevideo, Uruguay.
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D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000097:blood*; D017931:DNA Primers; D006801:Humans; D019169:Jurkat Cells; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood* / Q000276:immunology; D017350:N-Acetylgalactosaminyltransferases / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D017931:DNA Primers; C553205:GALNT11 protein, human; D017350:N-Acetylgalactosaminyltransferases
BSA; CD19; CD3; CLL; DNA complementary to RNA; FBS; GALNT11; GAPDH; GalNAc-T transferases; GalNAc-Ts; Gene that encode GalNAc-T11; Glyceraldehyde 3-phosphate dehydrogenase; IGHV; IIF; Ig; LPL; MMLV; Molecular marker; Moloney Murine Leukemia Virus; Mut; O-glycosylation; PA-gel electrophoresis; PAGE; PB; PBMCs; PBS; PCA; REST; Relative Expression Software Tool; SDS; Tn antigen; UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase; UM; VVB4; ZAP-70; aa; amino acid(s); base pair; bovine serum albumin; bp; cDNA; chronic lymphocytic leukemia; cluster of differentiation 19; cluster of differentiation 3; fetal bovine serum; immunoglobulin heavy chain variable region; immunoglobulin(s); indirect immunofluorescence; isolectin B4 from Vicia villosa; lipoprotein lipase; mAB; monoclonal Antibody; mutated; peptide competition assay; peripheral blood; peripheral blood mononuclear cells; phosphate-buffered saline; qPCR; quantitative real time PCR; sodium dodecyl sulfate; unmutated; zeta-associated protein 70