Vitamin B12 deficiency reduces proliferation and promotes differentiation of neuroblastoma cells and up-regulates PP2A, proNGF, and TACE.

Abstract

Vitamin B12 (cobalamin, Cbl) is indispensable for proper brain development and functioning, suggesting that it has neurotrophic effects beside its well-known importance in metabolism. The molecular basis of these effects remains hypothetical, one of the reasons being that no efficient cell model has been made available for investigating the consequences of B12 cellular deficiency in neuronal cells. Here, we designed an approach by stable transfection of NIE115 neuroblastoma cells to impose the anchorage of a chimeric B12-binding protein, transcobalamin-oleosin (TO) to the intracellular membrane. This model produced an intracellular sequestration of B12 evidenced by decreased methyl-Cbl and S-adenosylmethionine and increased homocysteine and methylmalonic acid concentrations. B12 deficiency affected the proliferation of NIE115 cells through an overall increase in catalytic protein phosphatase 2A (PP2A), despite its demethylation. It promoted cellular differentiation by improving initial outgrowth of neurites and, at the molecular level, by augmenting the levels of proNGF and p75(NTR). The up-regulation of PP2A and pro-nerve growth factor (NGF) triggered changes in ERK1/2 and Akt, two signaling pathways that influence the balance between proliferation and neurite outgrowth. Compared with control cells, a 2-fold increase of p75(NTR)-regulated intramembraneous proteolysis (RIP) was observed in proliferating TO cells (P < 0.0001) that was associated with an increased expression of two tumor necrosis factor (TNF)-alpha converting enzyme (TACE) secretase enzymes, Adam 10 and Adam 17. In conclusion, our data show that B12 cellular deficiency produces a slower proliferation and a speedier differentiation of neuroblastoma cells through interacting signaling pathways that are related with increased expression of PP2A, proNGF, and TACE.

• Authors: Shyue-fang Battaglia-Hsu, Nassila Akchiche, Nicole Noel, Jean-Marc Alberto, Elise Jeannesson, Carlos Enrique Orozco-Barrios, Daniel Martinez-Fong, Jean-Luc Daval, Jean-Louis Guéant
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 106 Issue 51 Pg. 21930-5 (Dec 22 2009) ISSN: 1091-6490 [Electronic] United States
• PMID: 19959661 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Protein Precursors
• pro-nerve growth factor, human
• Nerve Growth Factor
• Protein Phosphatase 2
• ADAM Proteins
• ADAM17 Protein
• ADAM17 protein, human

Topics

• ADAM Proteins (metabolism)
• ADAM17 Protein
• Cell Differentiation
• Cell Line, Tumor
• Cell Proliferation
• Humans
• Nerve Growth Factor (metabolism)
• Neuroblastoma (metabolism, pathology)
• Plasmids
• Protein Phosphatase 2 (metabolism)
• Protein Precursors (metabolism)
• Up-Regulation
• Vitamin B 12 Deficiency (metabolism, pathology)