Details

Autor(en) / Beteiligte

• Bacon, C L
• O'Driscoll, E
• Regan, C M

Titel

Valproic acid suppresses G1 phase-dependent sialylation of a 65kDa glycoprotein in the C6 glioma cell cycle

Ist Teil von

• International journal of developmental neuroscience, 1997-10, Vol.15 (6), p.777

Ort / Verlag

United States

Erscheinungsjahr

1997

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• The influence of valproate on in vitro glycosylation events in C6 glioma has been investigated, as this major human teratogen restricts proliferation in the mid-G1 phase of the cycle and alters the prevalence and/or glycosylation state of cell surface glycoproteins with the potential to mediate cell-cell and cell matrix interactions critical to development. C6 glioma cultured continuously in the presence of 1 mM valproate exhibited a significant depression of exponential growth but attained confluency one day later, when the majority of cells entered the G1 phase of the cycle. Glycoprotein sialyltransferase, which exhibited a four-fold increase during exponential growth and a small decrease at confluency, was markedly attenuated in valproate-exposed cells in a manner which was indirect. This was associated with an inhibition of transient alpha2,3 sialylation of a 65 kDa glycoprotein expressed maximally at 4 hr into the G1 phase of the cell cycle. This effect was cell-cycle phase-specific, as exposure of synchronized cells to valproate inhibited transient sialylation at 4 and 5 hr into the G1 phase. Inhibition of the 65 kDa glycoprotein sialylation by valproate is suggested to arise from impaired signal transduction preceding the eventual arrest by the drug at a 5-6 hr G1 phase restriction point.