[Tumor therapy: control of results by analysis of polyamines?]

High-resolution reversed-phase high-performance liquid chromatography analysis of polyamines and their monoacetyl conjugates by fluorescence detection after derivatization with N-hydroxysuccinimidyl 6-quinolinyl carbamate

A highly sensitive, accurate, and reproducible HPLC method for the determination of all natural polyamines and their monoacetyl conjugates is described. The presented method is based on precolumn derivatization with N-hydroxysuccinimidyl 6-quinolinyl carbamate (HSQC) followed by C18-HPLC separation using a ternary gradient and fluorescence detection (lambda Ex = 248 nm, lambda Em = 398 nm). The derivatives of the four main polyamines (putrescine, cadaverine, spermidine, and spermine) and the internal standard were synthesized on a preparative scale and characterized, especially with respect to their molar absorptivities and fluorescence quantum yields. The limits of detection of the highly stable derivatives ranged from 30 to 130 fmol (injection volume 10 microliters) for putrescine and N-acetylcadaverine, respectively (signal to noise ratio = 10), with excellent linearity within the range from 1 to 100 microM. High reproducibility for both retention times and peak areas, with coefficients of variation ranging from 0.14 to 0.88% and from 1.83 to 3.80%, respectively, were achieved. Provided that deproteinization of the samples was carried out immediately, recoveries of the analytes from homogenates of pancreatic cancer xenografts were high and reproducible. The optimized method was applied to the determination of the polyamine content of cultured pancreatic cancer cells and of tissue from colorectal adenocarcinoma, proving precise and reproducible quantification in these complex biological matrices.

Polyamines

Putrescine, spermidine, spermine and their derivatives are considered to be potential markers of certain diseases. Routine methods have, therefore, been developed in the course of the last decade. Several automated liquid chromatographic and gas chromatographic methods are presently at our disposal, which meet the practical requirements of sensitivity and specificity. They make the routine application of gas chromatographic-mass spectrometric methods dispensable. Very recently the amino acids deriving from polyamines have also been taken into consideration as tumour markers. Their separation by capillary gas chromatography has been reported. Separation of ion pairs on reversed-phase columns may also prove useful in the establishment of complete concentration profiles of polyamines and their derivatives in tissues and body fluids.

Urinary polyamine excretion by tumor-bearing and tumor-free mice exposed to cyclophosphamide, 5-fluorouracil and 6-mercaptopurine

The effects of cytostatic treatment on urinary polyamine excretion have been investigated in tumor-bearing (either Ehrlich carcinoma of S 180 sarcoma) and in tumor-free mice. The animals were exposed to single or multiple treatment with various doses of cyclophosphamide, 5-fluorouracil, or 6-mercaptopurine. Treatment invariably enhanced polyamine excretion dependent on dose and effectiveness of the cytostatic drug. The most pronounced increases were observed in the excretion of spermine and putrescine, with peak excretion usually occurring after 1-2 and 3-4 days, respectively. The urinary excretion of spermidine was relatively modest in untreated mice, but the increases observed following drug treatment were high in proportion. Significant differences in urinary polyamine excretion were observed between tumor-free and tumor-bearing animals following treatment with all cytostatic agents. Peak values were invariably higher in tumor-bearing mice even in those with small, barely detectable tumors. After discontinuation of treatment polyamine excretion returned to normal values and stabilized in groups in which regression predominated, whereas in those groups of animals which showed little or no tumor regression urinary polyamine levels gradually increased again during a 2-week observation period.