Ascorbic acid recycling in N-myc amplified human neuroblastoma cells.
The present study investigated the ability of two neuroblastoma cell lines (SK-N-SH, with one copy of N-myc, and SK-N-BE(2), with over 150 copies of N-myc) to recycle ascorbate by quantifying semidehydroascorbate reductase and dehydroascorbate reductase activities. Both cell lines expressed dehydroascorbate activity (SK-N-SH 28.4 +/- 9.8, SK-N-BE(2) 21.7 +/- 5.2 nmol/min/mg protein). Intracellular semidehydroascorbate activity was present only in SK-N-BE(2) cells (4.7 +/- 1.2 nmol/min/mg protein). Extracellular ascorbate was regenerated by semidehydroascorbate membrane activity, the activity of SK-N-BE(2) being twice that of SK-N-SH cells. The present data may explain the ability of the tumor to progress or regress through mechanisms involving both myc oncogene and apoptosis.
Savini
I
I
Department of Experimental Medicine and Biochemical Sciences, University Tor Vergata, Rome, Italy.
D'Angelo
I
I
Annicchiarico-Petruzzelli
M
M
Bellincampi
L
L
Melino
G
G
Avigliano
L
L
D001205:Ascorbic Acid / Q000378:metabolism*; D005784:Gene Amplification; D016259:Genes, myc; D006801:Humans; D009243:NAD / Q000378:metabolism; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D014407:Tumor Cells, Cultured
D009243:NAD; D001205:Ascorbic Acid