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Transfection of 2,6 and 2,3‐sialyltransferase genes and GlcNAc‐transferase genes into human glioma cell line U‐373 MG affects glycoconjugate expression and enhances cell death
Author(s) -
Dawson G.,
Moskal J. R.,
Dawson S. A.
Publication year - 2004
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02435.x
Subject(s) - sialyltransferase , glycosyltransferase , transfection , microbiology and biotechnology , programmed cell death , cell culture , chemistry , viability assay , apoptosis , sialic acid , biology , biochemistry , gene , genetics
Human glioma cell line U‐373 MG expresses CMP‐NeuAc : Galβ1,3GlcNAc α2,3‐sialyltransferase [EC No. 2.4.99.6] (α2,3ST), UDP‐GlcNAc : β‐ d ‐mannoside β1,6‐ N ‐acetylglucosaminyltransferase V [EC 2.4.1.155] (GnT‐V) and UDP‐GlcNAc3: β‐ d ‐mannoside β1,4‐ N ‐acetylglucosaminyltransferase III [EC 2.4.1.144] (GnT‐III) but not CMP‐NeuAc : Galβ1,4GlcNAc α2,6‐sialyltransferase [EC 2.4.99.1] (α2,6ST) under normal culture conditions. We have previously shown that transfection of the α2,6ST gene into U‐373 cells replaced α2,3‐linked sialic acids with α2,6 sialic acids, resulting in a marked inhibition of glioma cell invasivity and a significant reduction in adhesivity. We now show that U‐373 cells, which are typically highly resistant to cell death induced by chemotherapeutic agents (< 10% death in 18 h), become more sensitive to apoptosis following overexpression of these four glycoprotein glycosyltransferases. U‐373 cell viability showed a three‐fold decrease (from 20 to 60% cell death) following treatment with staurosporine, C2‐ceramide or etoposide, when either α2,6ST and GnT‐V genes were stably overexpressed. Even glycosyltransferases typically raised in cancer cells, such as α2,3ST and GnT‐III, were able to decrease viability two‐fold (from 20 to 40% cell death) following stable overexpression. The increased susceptibility of glycosyltransferase‐transfected U‐373 cells to pro‐apoptotic drugs was associated with increased ceramide levels in Rafts, increased caspase‐3 activity and increased DNA fragmentation. In contrast, the same glycosyltransferase overexpression protected U‐373 cells against a different class of apoptotic drugs, namely the phosphatidylinositol 3‐kinase inhibitor LY294002. Thus altered surface protein glycosylation of a human glioblastoma cell line can lead to lowered resistance to chemotherapeutic agents.