Selective elevation of the N1-acetylspermidine level in human colorectal adenocarcinomas

The association of N1-acetylspermidine with human colorectal adenocarcinomas has been evaluated in this study. Free polyamines and their monoacetylated forms in adenocarcinomas, adenomas, and apparently healthy mucosae were determined using high-performance ion-exchange chromatography. The N1-acetylspermidine levels in well- and moderately differentiated adenocarcinomas were 27.30 +/- 3.13 (S.E.) (n = 99) and 22.86 +/- 3.60 (n = 22) nmol/g, wet weight, respectively. These values were significantly higher than those of benign adenomas (5.38 +/- 0.85 nmol/g, n = 31) and of control mucosae. The N1-acetylspermidine levels in control mucosae on the oral and anal side of adenocarcinomas were 5.84 +/- 1.44 (n = 57) and 7.92 +/- 2.89 (n = 50) nmol/g, respectively; no significant difference was observed between control mucosae and adenomas. The mean levels of three polyamines, putrescine, spermidine, and spermine in both adenomas and adenocarcinomas were about twice as high as those of control mucosae. The molar ratios of spermidine to spermine were significantly greater in both adenomas and adenocarcinomas than in control tissues. There was no obvious correlation between the free polyamine concentrations and the degree of malignancy of the colorectal tumors. These results suggest that the metabolism of N1-acetylspermidine in colorectal adenocarcinomas is quite different from that in adenomas and in nonneoplastic mucosae and that N1-acetylspermidine can be a promising biochemical marker of cancer in the human large intestine.