The metabolic fate of [3H-methyl]choline in cultured human neuroblastoma cell lines, LA-N-1 and LA-N-2

Singh, Indrapal N.; Sorrentino, Giuseppe; Massarelli, R.; Kanfer, Julian N.

doi:10.1007/bf03160997

Cited by 4 publications

(3 citation statements)

References 24 publications

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“…Previous reports demonstrated that LA-N-2 cells propagated in the presence of lop5 M retinoic acid (RA) underwent morphological differentiation and there were accompanying changes in certain enzymatic activities (Singh et al, 1990). Therefore, it seemed reasonable to determine whether TPA exerted a similar influence on the labeling with Table I, whic;.. shows that the retinoic acid-grown cells as compared to control cells 1) were unresponsive to TPA with respect to lipid and protein labeling and 2) had a reduced capacity to incorporate either labeled Ea or labeled Ser into lipids and proteins but increased incorporation of labeled Cho into lipids.…”

Section: Retinoic Acid Grown Cellsmentioning

confidence: 99%

“…The human neuroblastoma cell line, LA-N-2 (passage Sl), was obtained from Dr. Robert Seeger, University of California, Los Angeles. The maintenance and growth conditions for this cell line were as described by Singh et al (1990). At 8 days in culture (DIV) the LA-N-2 cell cultures containing approximately 1 mg protein were washed once with serum-free L-15 medium and replaced with 5 ml of serum-free medium containing either ['4C]Cho (1.2 pCi/ ml), [14C]Ea (1.5 pCi/ml), or [14C]Ser (1 pCi/ml) along with either 100 nM TPA in dimethylsulfoxide (DMSO) or DMSO alone (0.1% final concentration).…”

Section: Cell Culture and Labeling Protocolsmentioning

confidence: 99%

“…Previous reports demonstrated that LA-N-2 cells propagated in the presence of lop5 M retinoic acid (RA) underwent morphological differentiation and there were accompanying changes in certain enzymatic activities (Singh et al, 1990). Therefore, it seemed reasonable to determine whether TPA exerted a similar influence on the labeling with [14C]L-Ser, ['4C]Cho, and [14C]Ea of retinoic acid-induced differentiated LA-N-2 cells as those propagated in the absence of retinoic acid.…”

Section: Retinoic Acid Grown Cellsmentioning

confidence: 99%

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Phorbol esters modulate phospholipid metabolism in a human cholinergic cell line, LA‐N‐2: A possible role for the base exchange enzymes

Singh

McCartney

Sorrentino

et al. 1992

J of Neuroscience Research

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It was shown that in LA-N-2 cells prelabeled with [3H-methyl]choline for 24 hr (Singh et al.: Mol Chem Neuropathol 14:53-66, 1991) the major intracellular and extracellular hydrophilic compound was phosphorylcholine. LA-N-2 cells were labeled with [14C-methyl]choline for 24 hr, harvested, and incubated in Hepes/BSA/saline buffer for varying periods of time. The radioactive compound present in the cytosol and released into Hepes/BSA/saline buffer medium in the presence or absence of TPA was phosphorylcholine. There was a gradual increase in the appearance of radioactivity in the medium and this corresponded to a gradual decline in the radioactivity present in the cytosolic compartment with a statistically significant P value of less than .005. Identical results were obtained with prelabeled cells subsequently incubated with TPA. There was no significant change in the amount of radioactivity associated with lipid suggesting that the phosphorylcholine may be released directly from the cytosolic compartment into the medium rather than originating through a phospholipase-C catalyzed hydrolysis of phosphatidylcholine. This possibility received support from experiments in which cells were electropermeabilized in the presence of radioactive phosphorylcholine. It was found that the introduced [14C]phosphorylcholine was released intact into the incubation medium from the cytosolic compartment. The incorporation of [14C]choline, [14C]ethanolamine, and [14C]serine by LA-N-2 cells into their corresponding phospholipids was investigated in the presence or absence of TPA. The presence of TPA increased the amount of radioactivity incorporated into the phospholipids with a corresponding decrease in the amount of radioactivity in the cytosolic compartment compared to control cultures. There were no detectable differences between TPA exposed and control cells in the distribution of radioactivity in free choline, phosphorylcholine, or CDP-choline of [14C] choline labeled cells. This indicates that the increased lipid labeling was not accompanied by enhanced labeling of the intermediates of the de novo pathway. This effect of TPA in altering the distribution of labeling of the cytosolic and lipid components was not demonstrable with cells grown in the presence of 10(-5) M retinoic acid.

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Section: Retinoic Acid Grown Cellsmentioning

confidence: 99%

Section: Cell Culture and Labeling Protocolsmentioning

confidence: 99%

“…Previous reports demonstrated that LA-N-2 cells propagated in the presence of lop5 M retinoic acid (RA) underwent morphological differentiation and there were accompanying changes in certain enzymatic activities (Singh et al, 1990). Therefore, it seemed reasonable to determine whether TPA exerted a similar influence on the labeling with [14C]L-Ser, ['4C]Cho, and [14C]Ea of retinoic acid-induced differentiated LA-N-2 cells as those propagated in the absence of retinoic acid.…”

Section: Retinoic Acid Grown Cellsmentioning

confidence: 99%

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Phorbol esters modulate phospholipid metabolism in a human cholinergic cell line, LA‐N‐2: A possible role for the base exchange enzymes

Singh

McCartney

Sorrentino

et al. 1992

J of Neuroscience Research

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The Conversion of Ethanolamine Containing Compounds to Choline Derivatives and Acetylcholine

Massarelli¹,

Andriamampandry²,

Haidar³

et al. 1993

Phospholipids and Signal Transmission

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Incorporation of [3H]ethanolamine into acetylcholine by a human cholinergic neuroblastoma clone

Haidar¹,

Carrara

Andriamampandry³

et al. 1994

Neurochem Res

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Human neuroblastoma cholinergic LA-N-2 cells were used as an experimental model to test the possibility that the methylation of phosphoethanolamine (PEtn) to phosphocholine (PCho) and free choline (Cho) (Andriamampandry et al. 1989) could contribute to acetylcholine (AcCho) synthesis. LA-N-2 cells were incubated with [3H]Cho for 90 min and 22.7% of the radioactivity was present in PCho, 18.5% in free Cho and 4.8% as AcCho. The ratio of Cho/AcCho, however, was of about 1 after 16 hours of incubation. The incorporation of 10 microM [3H]ethanolamine (Etn) into MeEtn, PMeEtn, PMe2Etn and their corresponding phospholipids was reduced in cells incubated in medium containing 7.2 microM choline as compared to cells incubated in medium devoid of choline indicating that the lack of Cho from the incubation medium stimulated the conversion of PEtn to Cho water soluble derivatives. Incubation of LA-N-2 cells with [3H]Etn led to the labelling of [3H]AcCho. Cultures incubated in parallel with [3H]Cho showed that roughly 10% of [3H]AcCho obtained after 16 hrs of incubation with the Cho label derived from [3H]Etn. The synthesis of Cho and AcCho from Etn may be enhanced after cellular differentiation induced by the growth of the cells in the presence of retinoic acid (RA). The results indicate that the methylation of [3H]Etn and/or of [3H]PEtn may be used by cholinergic neurons as precursor for AcCho.

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The metabolic fate of [3H-methyl]choline in cultured human neuroblastoma cell lines, LA-N-1 and LA-N-2

Cited by 4 publications

References 24 publications

Phorbol esters modulate phospholipid metabolism in a human cholinergic cell line, LA‐N‐2: A possible role for the base exchange enzymes

Phorbol esters modulate phospholipid metabolism in a human cholinergic cell line, LA‐N‐2: A possible role for the base exchange enzymes

The Conversion of Ethanolamine Containing Compounds to Choline Derivatives and Acetylcholine

Incorporation of [3H]ethanolamine into acetylcholine by a human cholinergic neuroblastoma clone

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