Urinary Excretion of Free and Acetylated Polyamines in Hepatocellular Carcinoma

Polyamines (putrescine, spermidine and spermine) are essential for the proliferation of normal and neoplastic cells, and have been repeatedly recommended as tumor markers, with contrasting and elusive results. In the present study the urinary excretion of free and acetylated polyamines was measured in patients with hepatocellular carcinoma (HCC), cirrhotics and control subjects. Separation and quantification of dansyl-derivatives of free, acetylated and total polyamines was performed by reverse-phase high-performance liquid chromatography. The results show that the urinary excretion of total, free, and acetylated polyamines is significantly higher in HCC patients than in cirrhotics and controls (p<0.001). The N1/N8 acetyl-spermidine molar ratio was found to be higher in HCC patients than in cirrhotics and controls (p<0.001). No correlation was found between urinary excretion of polyamines and serum alpha-fetoprotein, tumor size and severity of liver cirrhosis. The results show that increased urinary excretion of free and acetylated polyamines, as well as an altered N1/N8-acetyl-spermidine molar ratio, is a sensible but not specific feature of HCC patients; polyamines may play a role in human carcinogenesis, but their determination does not seem reliable for the early detection of liver cancer.

Purification and characterization of polyamine oxidase from Ascaris suum

The interconversion of polyamines in the parasite nematode Ascaris suum by a novel type of polyamine oxidase was demonstrated. The nematode enzyme was clearly distinguishable from monoamine and diamine oxidases as well as from the mammalian polyamine oxidase, as shown by the use of the specific inhibitors pargyline, aminoguanidine and MDL 72527 respectively. All three inhibitors had no effect on the parasite polyamine oxidase, and the enzyme did not accept diamines such as putrescine, cadaverine or histamine as substrates. The parasite polyamine oxidase selectively oxidizes spermine and spermidine but not N-acetylated polyamines, whereas the mammalian tissue-type polyamine oxidase shows preference for the N-acetylated polyamines. These results suggest a regulatory function of the nematode polyamine oxidase in the degradation and interconversion of polyamines in parasite nematodes. The enzyme was purified to homogeneity by gel filtration, preparative isoelectric focusing and subsequent affinity chromatography on spermine- and berenil-Sepharose 4B. With respect to reaction type, the prosthetic group FAD, the molecular mass (66 kDa) and the contents of thiol and carbonyl groups, the polyamine oxidase from A. suum is similar to the isofunctional enzyme of mammalian tissue.