Folate and pterin metabolism by cancer cells in culture.
Malignant cells grown in culture excrete into their growth medium a folate catabolite that can be seen as a blue-fluorescent region on paper chromatograms of such media. This folate catabolite has now been identified by paper chromatography, thin-layer chromatography, and combined gas chromatography-mass spectrometry as 6- hydroxymethylpterin and not as pterin-6-carboxaldehyde as previously reported. Moreover, when pterin-6-carboxaldehyde was added to the growth medium of logarithmically growing malignant cells, it was primarily reduced to 6-hydroxymethylpterin. In contrast pterin-6-carboxylate was the principal product formed from added pterin-6-carboxaldehyde by normal established cell lines in culture. These results have been interpreted as indicative of a possible mechanism of folate catabolism in malignant cells. Folic acid or another folate derivative is oxidatively cleaved at the C-9-N-10 bond to yield pterin-6-carboxaldehyde as one of the products. This derivative is subsequently reduced to 6-hydroxymethylpterin, which is excreted into the growth medium.
D002478:Cells, Cultured; D002849:Chromatography, Gas; D002854:Chromatography, Paper; D002855:Chromatography, Thin Layer; D005453:Fluorescence; D005492:Folic Acid / Q000378:metabolism*; D013058:Mass Spectrometry; D009374:Neoplasms, Experimental / Q000378:metabolism*; D011622:Pterins / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors
D011622:Pterins; D005492:Folic Acid; D014969:Xanthine Oxidase