Development of a sensitive and accurate enzyme-linked immunosorbent assay (ELISA) system that can replace HPLC analysis for the determination of N1,N12-diacetylspermine in human urine

N1, N12-Diacetylspermine Is Elevated in Colorectal Cancer and Promotes Proliferation through the miR-559/CBS Axis in Cancer Cell Lines

N1, N12-Diacetylspermine (DiAcSpm) has been reported to be upregulated in the urine of cancer patients. Mass spectrometry has shown elevated DiAcSpm expressions in colorectal cancer (CRC) tissues. However, the diagnostic application of DiAcSpm is not available due to a lack of diagnostic grade antibodies. Also, its biological roles in CRC cells remain unexplored. In the present study, we developed an antibody that directly detected DiAcSpm expression in paraffin-embedded tissues. We also characterized its biological characteristics and underlying mechanisms. Polyclonal antibodies were generated by immunizing animals with a synthetic product of DiAcSpm. Antibody DAS AB016 showed strong sensitivity against DiAcSpm in CRC tissues. Immunohistochemistry results showed that DiAcSpm expression was significantly elevated in CRC tissues. High levels of DiAcSpm correlated with the clinical stage and Ki67 index. DiAcSpm treatment increased levels of proliferation, cell cycle progression, and cyclin D1 and cyclin E proteins in CRC cell lines, SW480 and Caco-2. DiAcSpm also upregulated ATP production in these two cell lines. RNA-sequencing showed that DiAcSpm downregulated miR-559, which was confirmed using RT-qPCR. The luciferase reporter assay, western blotting, and RT-qPCR showed that cystathionine β-synthase (CBS) was the target of miR-559. miR-559 inhibited, while CBS accelerated, CRC proliferation. In addition, CBS siRNA knockdown blocked the biological effects of DiAcSpm on CRC cells. In conclusion, DiAcSpm was found to be increased in CRC tissues using a newly developed antibody. DiAcSpm accelerated CRC proliferation by regulating the miR-559/CBS axis.

MnO2 Nanosheet-based Fluorescence Sensing Platform for Sensitive Detection of Endonuclease

A novel fluorescence sensing platform for ultrasensitive detection of S1 nuclease activity has been constructed based on MnO₂ nanosheets and FAM labeled single-stranded DNA (FAM-ssDNA). In this system, MnO₂ nanosheets were found to have different adsorbent ability toward ssDNA and mono- or oligonucleotide fragments. FAM-ssDNA could adsorb on MnO₂ nanosheets and resulted in significant fluorescence quenching through fluorescence resonance energy transfer (FRET), while mono- or oligonucleotide fragments could not adsorb on MnO₂ nanosheets and still retained strong fluorescence emission. With the addition of S1 nuclease, FAM-ssDNA was cleaved into mono- or oligonucleotide fragments, which were not able to adsorb on MnO₂ nanosheets and the fluorescence signal was never quenched. The different fluorescence intensity allowed for examination of S1 nuclease activity. The developed method can detect S1 nuclease activity in the range of 0 - 20 U mL^-1 with a detection limit of 0.05 U mL^-1. Benefits of the system include less time-consuming processes and more simple design compared to other endonuclease assays. Satisfactory performance for S1 nuclease in complex samples has been successfully demonstrated with the system. The developed assay could potentially provide a new platform in bioimaging and clinical diagnosis.

Urinary Polyamines as Biomarkers for Ovarian Cancer

OBJECTIVES

Elevated concentrations of polyamines have been found in urine of patients with malignant tumors, including ovarian cancer. Previous research has suffered from poorly standardized detection methods. Our liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is capable of simultaneous standardized analysis of most known polyamines. Liquid chromatography-tandem mass spectrometry has not previously been used in the differential diagnostics of ovarian tumors in postmenopausal women.

MATERIALS AND METHODS

In this prospective study, postmenopausal women (n = 71) presenting with an adnexal mass and, as controls, women with genital prolapse or urinary incontinence scheduled for surgery (n = 22) were recruited in the study. For analysis of the polyamines, a morning urine sample was obtained before surgery. Preoperative serum CA125 concentrations were determined in the study group.

RESULTS

Twenty-three women with benign and 37 with malignant ovarian tumors were eligible. Of all analyzed polyamines, only urinary N,N-diacetylspermine showed statistically significant differences between all groups except controls versus benign tumors. N,N-diacetylspermine was elevated in malignant versus benign tumors (P < 0.001), in high-grade versus low malignant potential tumors (P < 0.001), in stage III to IV versus stage I to II cancers (P < 0.001), and even in early-stage cancer (stage I-II) versus benign tumors (P = 0.017). N,N-diacetylspermine had better sensitivity (86.5%) but lower specificity (65.2%) for distinguishing benign and malignant ovarian tumors than CA125 with a cut-off value of 35 kU/L (sensitivity, 75.7%; specificity, 69.6%).

CONCLUSIONS

Urinary N,N-diacetylspermine seems to be able to distinguish benign and malignant ovarian tumors as well as early and advanced stage, and low malignant potential and high-grade ovarian cancers from each other, respectively.

Clinical Significance of Urinary N1,N12-Diacetylspermine Levels in Patients with Hepatocellular Carcinoma

Background/aim

N1,N12-diacetylspermine (DiAcSpm), a diacetylpolyamine which was recently identified in urine, appeared to be a useful tumor marker for urogenital cancers. Here we examined the clinical significance of urinary DiAcSpm as a tumor marker for hepatocellular carcinoma (HCC).

Methods

Urine samples were collected from patients with HCC and benign liver diseases. Urinary levels of DiAcSpm were measured by ELISA, which was newly developed in order to analyze large numbers of samples.

Results

The appropriate threshold value was set at 325 nM/g·creatinine. The sensitivity of the DiAcSpm assay for HCC was 65.5% and the specificity calculated between HCC and liver cirrhosis was 76.0%. The percentage of DiAcSpm-positive HCC patients was similar to that for AFP or PIVKA-II. At more advanced clinical stages, the positive percentage of these three markers increased but the DiAcSpm levels appeared to move independently of AFP and PIVKA-II. In HCC patients, the DiAcSpm levels reflected the progression of disease or the effect of treatment.

Conclusions

DiAcSpm levels were found to reflect the severity, activity or viability of HCC. Urinary DiAcSpm can therefore be considered one of the useful indexes for patients with HCC.

Urinary N1, N12-diacetylspermine is a non-invasive marker for the diagnosis and prognosis of non-small-cell lung cancer

BACKGROUND

Early detection of non-small-cell lung cancer (NSCLC) and accurate prognostic risk assessment could improve patient outcome. We examined the significance of urinary N(1), N(12)-diacetylspermine (DiAcSpm) in the detection and prognostic stratification of NSCLC patients.

METHODS

A DiAcSpm/cutoff ratio (DASr) was established for 260 NSCLC patients, 99 benign lung disease patients, and 140 healthy volunteers, using colloidal gold aggregation methods. The DASr was compared between patients and healthy controls, and the prognostic significance of DASr was examined.

RESULTS

The median urinary DASr of NSCLC patients was significantly higher than that of healthy controls (0.810 vs 0.534, P<0.001). The DASr was higher in squamous cell carcinoma (SqCC) patients than in adenocarcinoma patients (1.18 vs 0.756, respectively, P=0.039). An increased urinary DASr value was significantly associated with pathological stage, other histological invasive factors and unfavourable outcomes in patients with completely resected NSCLC. Multivariate Cox regression analysis showed that increased urinary DASr was an independent prognostic factor (hazard ratio=4.652, 95% confidence interval (CI), 2.092-10.35; P<0.001).

CONCLUSIONS

Urinary DASr was significantly increased in NSCLC, especially in SqCC. Urinary DASr was an independent poor prognostic indicator in patients with completely resected NSCLC. The DASr could be a useful biomarker for detecting malignancies and predicting prognosis.

Diagnostic approach to breast cancer patients based on target metabolomics in saliva by liquid chromatography with tandem mass spectrometry

BACKGROUND

Breast cancer is one of the most fearful diseases due to its increasing worldwide prevalence. A number of screening tests has been employed including clinical examinations and mammography. However, another screening method, which is a simple, not embarrassing, and low cost, is highly desired. Based on these findings, we are currently investigating the determination of polyamines including their acetylated structures for the diagnosis of breast cancer patients. We established a diagnostic approach to breast cancer patients based on the ratios of polyamines in saliva by a UPLC-MS/MS analysis.

METHODS

Twelve polyamines including their acetylated form were labeled with DBD-F, separated by a reversed-phase chromatography and detected by a Xevo TQ-S tandem mass spectrometer.

RESULTS

Eight polyamines (e.g., SPM, CAD, Ac-SPM, N1-Ac-SPD, N8-Ac-SPD) strongly correlated with the cancer patients. A simple 1-order equation was developed for the discrimination of the breast cancer patients and healthy persons (Y=0.5XSPM-3XAc-SPM-0.15XSPD-3.5XN8-Ac-SPD+0.5XN1-Ac-SPD+0.04XCAD). The concordance rate of the breast cancer patients and the healthy persons by the equation was 88% and 76% on the training set, respectively, whereas those on the validation set was both 88%. The score Y in the equation tended to correlate with the cancer stage of the patients and increased with the more serious conditions. The determination of polyamines in the saliva after the cancer patient operations was also performed to identify the concentration change before and after the surgical treatment. The discriminant analysis using 6 polyamines (i.e., N8-Ac-SPD, N1-Ac-SPD, CAD, DAc-SPD, PUT, and Ac-PUT), which were the most influenced molecules derived from the ROC analysis, was performed using the relative percentage. Both the sensitivity and specificity indicated nearly 80% from the ROC analysis result using the ratio of N8-Ac-SPD/(N1-Ac-SPD+N8-Ac-SPD).

CONCLUSION

The discrimination equation appears to be useful for the diagnosis of breast cancer patients. Furthermore, the ratio of N8-Ac-SPD/(N1-Ac-SPD+N8-Ac-SPD) may be adopted as an index of the health status after the surgical treatment.

A dual-amplification fluorescent sensing platform for ultrasensitive assay of nuclease and ATP based on rolling circle replication and exonuclease III-aided recycling

A ultrasensitive, easy operated and robust assay of S1 nuclease in real samples and ATP has been successfully achieved with the dual-amplification strategy based on rolling circle replication and Exo III-aided recycling.

Simple and convenient G-quadruplex-based fluorescence assay of micrococcal nuclease activity

An ultrasensitive and straightforward fluorescence sensing platform for MNase activity has been developed based on NMM/G-quadruplexes.

Dietary polyamine intake and polyamines measured in urine

Dietary polyamines have recently been associated with increased risk of pre-malignant colorectal lesions. Because polyamines are synthesized in cells and taken up from dietary sources, development of a biomarker of exposure is challenging. Excess polyamines are primarily excreted in the urine. This pilot study seeks to identify dietary correlates of excreted urinary polyamines as putative biomarkers of exposure. Dietary polyamines/other nutrients were estimated from a food frequency questionnaire (FFQ) and correlated with urinary levels of acetylated polyamines in 36 men using 24-h urine samples. Polyamines, abundant in cheese and citrus, were highly positively correlated with urinary N(8)-acetylspermidine (correlation coefficient; r = 0.37, P = 0.03), but this correlation was attenuated after adjustment for total energy intake (r = 0.07, P = 0.68). Dietary energy intake itself was positively correlated with urinary total acetylated polyamine output (r = .40, P = 0.02). In energy-adjusted analyses, folic acid and folate from food were associated with urinary N(1),N(12)-diacetylspermine (r = 0.34, P = 0.05 and r = -0.39, P = 0.02, respectively). Red meat negatively correlated with total urinary acetylated polyamines (r = -0.42, P = 0.01). Our findings suggest that energy, folate, folic acid, saturated fat, and red meat intake, as opposed to FFQ-estimated dietary polyamines, are correlated with urinary polyamines.

A new label-free and turn-on strategy for endonuclease detection using a DNA-silver nanocluster probe

Endonuclease plays a vital role in a variety of biological processes and the assay of endonuclease activity and inhibitors is of high importance in the fields ranging from biotechnology to pharmacology. Howerer, traditional techniques usually suffer from time intensive, laborious, and cost-expensive. This work aims to develop a facile and sensitive method for endonuclease activity assay by making use of the fluorescence enhancement effect when DNA-silver nanoclusters (DNA-Ag NCs) are in proximity to guanine-rich DNA sequences. The system mainly consists of block DNA (B-DNA), G-DNA and Ag-DNA. B-DNA serves as the substrate of the endonuclease (S1 nuclease as the model enzyme). G-DNA, which is predesigned entirely complementary to B strand, contains a guanine-rich overhang sequence and hybridization part at the 5'-end. Ag-DNA involves a sequence for Ag NCs synthesis and a sequence complementary to the hybridization part of the G-DNA. In the "off" state, B-DNA plays the role as a blocker that inhibit the proximity between Ag NCs and guanine-rich DNA sequences, resulting in a low fluorescence readout. However, if S1 nuclease is introduced into the system, B-DNA was cleaved into mono- or short-oligonucleotides fragments, which could not hybridize with G-DNA. As a result, the subsequent addition of DNA-Ag NCs could bring guanine-rich DNA sequences close to the Ag NCs, accompanied by a significant fluorescence enhancement. Therefore, endonuclease activity could be successfully quantified by monitoring the variation in fluorescence intensity. In addition, this approach can also be applied for inhibitor screening of endonuclease. This label-free and turn-on fluorescent assays employing the mechanism proposed here for the detection of nuclease and inhibitors turn out to be sensitive, selective, and convenient.

Construction of an immunochromatographic determination system for N¹,N¹²-diacetylspermine

BACKGROUND

N(1),N(12)-diacetylspermine (DiAcSpm) is a recently identified tumor marker. Its concentration increases in the urine of cancer patients at early clinical stages. To utilize this characteristic feature and thus contribute to the early detection of cancer, we developed an immunochromatographic determination system for DiAcSpm.

METHODS

We examined the factors that affect the performance and stability of our determination system, including antibody selection and the conditions for the formation of stably dispersed antibody-coated gold nanoparticles. We then tested the performance of the system by determining the DiAcSpm concentration in human urine samples.

RESULTS

We constructed an immunochromatographic strip using anti-DiAcSpm antibody-coated gold nanoparticles in the conjugate pad and an acetylspermine-protein conjugate (a DiAcSpm mimic) immobilized on the analyzing membrane. The use of the immunochromatographic strip and an immunochromato-reader allowed for the quantitative determination of DiAcSpm in the range of 20 to 700 nM. The analytical values obtained by this method were well correlated with those determined by a colloidal gold aggregation procedure using an automatic biochemical analyzer. The immunochromatographic strip was stable for at least 8 weeks at 50°C.

CONCLUSIONS

A competitive immunochromatographic device for DiAcSpm determination was developed in this study. This simple device will contribute to increasing the opportunities for early cancer detection and timely care.

High-throughput LC-MS/MS based simultaneous determination of polyamines including N-acetylated forms in human saliva and the diagnostic approach to breast cancer patients

The determination of polyamines and their N-acetylated forms was performed by ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The polyamines efficiently reacted with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) in 0.1 M borax (pH 9.3) at 60 °C for 30 min. The resulting derivatives were analyzed by electrospray ionization (ESI)-MS and sensitively detected by selected reaction monitoring (SRM). Furthermore, a rapid separation of the polyamine derivatives within 10 min was performed by UPLC using an antipressurized column packed with 1.7-μm octadecylsilyl (ODS) silica gel. The limits of detection (S/N = 3) on the SRM chromatograms were at the attomole level (9-43 amol). This procedure was used to successfully determine 11 polyamines, including their N-acetylated forms, in the saliva of patients with primary and relapsed breast cancer and healthy volunteers. The level of several polyamines (Ac-PUT, Ac-SPD, Ac-SPM, DAc-SPD, and DAc-SPM) increases in breast cancer patients. Furthermore, the levels of three polyamines (Ac-SPM, DAc-SPD, and DAc-SPM) were significantly higher only in the relapsed patients. The present method proved highly sensitive and is characterized by specificity and feasibility for sample analysis. Consequently, the proposed method is useful for the noninvasive salivary diagnosis of cancer patients and could be applied to determine polyamines in several specimens of biological nature.

Excretion of N1, N12-diacetylspermine in the urine of healthy individuals

Background

Urinary N 1 ,N12-diacetylspermine (DiAcSpm) is a novel tumour marker that can be used to detect early cancers. In this study, we examined whether spot urine samples could represent the daily excretion of DiAcSpm after creatinine normalization and which factors should be taken into account in determining reference values for this biomarker.

Methods

We collected the following urine samples: (1) samples from seven healthy volunteers collected on each day of two 2-day sessions to examine the circadian variation of DiAcSpm excretion; (2) samples from 3952 male and 1782 female volunteers to estimate the DiAcSpm concentrations in apparently healthy adults and (3) samples from 16 female volunteers collected every morning over a 3-month period to examine the menstruation-related variation in DiAcSpm excretion. The DiAcSpm concentrations were determined by enzyme-linked immunosorbent assay or a colloidal gold aggregation procedure using DiAcSpm-specific antibodies.

Results

(1) The circadian variation of DiAcSpm in the urine was greatly diminished after creatinine normalization. (2) DiAcSpm was higher in females than in males, and the creatinine-normalized medians (95th percentile) of the urinary DiAcSpm concentrations were 149 (305) and 100 (192) nmol/g creatinine for females and males, respectively. (3) The mean concentrations of urinary DiAcSpm were lower after menstruation than before menstruation by approximately 30 nmol/g creatinine.

Conclusion

Spot urine samples obtained at any time of a day may be used to estimate the daily excretion of DiAcSpm in nmol DiAcSpm per gram creatinine. Sex, age and menstrual condition should be considered when determining the reference values for urinary DiAcSpm.

An ultra-high sensitive platform for fluorescence detection of micrococcal nuclease based on graphene oxide

Micrococcal nuclease (MNase) is the extracellular nuclease of Staphylococcus aureus (S. aureus). It preferentially digests single-stranded nucleic acids. The existence of MNase can be the standard to identify S. aureus and the content of MNase can be used to evaluate the pathogenicity of S. aureus. Herein, an ultra-high sensitive and selective fluorescent sensing platform for MNase is developed based on MNase-induced DNA strand scission and the difference in affinity of graphene oxide (GO) for single-stranded DNA containing different numbers of bases in length. In the absence of MNase, the adsorption of the dye-labeled ssDNA on GO makes the dyes close proximity to GO surface resulting in high efficiency quenching of fluorescence of the dyes. Conversely, and very importantly, in the presence of MNase, it cleaves the dye-labeled ssDNA into small fragments. The introduction of GO into the sensing solution results in weak quenching of the fluorescence of the dyes due to the weak affinity of the short dye-labeled oligonuleotide fragment to GO, and the fluorescence intensity gradually increases with increasing concentration of MNase. MNase can be detected in a range of 8×10⁻⁵ to 1.6×10⁻³ unit/mL with a detection limit of 2.7×10⁻⁵ unit/mL and good selectivity. The detection limit is of two orders of magnitude lower than those reported fluorescence MNase assays. Moreover, when the GO-based biosensor is used in S. aureus sample assays, preeminent fluorescence signals are obtained, thus the platform of the GO-based biosensor can be used to detect MNase in real-world samples.

The clinical usefulness of urinary N(1),N(12)-diacetylspermine (DiAcSpm) levels as a tumor marker in patients with colorectal cancer

The aim of this study was to evaluate the usefulness of urinary N(1),N(12)-diacetylspermine (DiAcSpm) measured by the colloidal gold aggregation method as a tumor marker for colorectal cancer (CRC). The preoperative urine of 113 CRC patients was collected, and the urinary DiAcSpm was measured by a reagent kit for DiAcSpm determination based on colloidal gold aggregation using automatic biochemical analyzers. The urinary DiAcSpm levels significantly correlated with distant metastasis and Tumor-Node-Metastasis (TNM) stage. The positive rates of urinary DiAcSpm were significantly higher than those of serum carcinoembryonic antigen (CEA) or cancer antigen 19-9 (CA19-9) in stages 0+I, II, III and IV. The positive rates of urinary DiAcSpm were also significantly higher than those of serum CEA or CA19-9 in the early and advanced CRC groups according to the Japan Classification of Colorectal Cancer. Therefore, urinary DiAcSpm, measured by a reagent kit for DiAcSpm determination based on colloidal gold aggregation, may be useful as a non-invasive tumor marker in patients with CRC.

A label-free, G-quadruplex DNAzyme-based fluorescent probe for signal-amplified DNA detection and turn-on assay of endonuclease

A novel G-quadruplex DNAzyme molecular beacon (G-DNAzymeMB) strategy is developed for assays of target DNA and restriction endonuclease. The detection system consists of G-DNAzymeMB strand and a blocker DNA by using the fluorescence of 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) catalyzed by G-DNAzymeMB as a signal reporter. G-DNAzymeMB exhibits peroxidase activity in its free hairpin structure, and forms a catalytically inactive hybrid when hybridized with blocker DNA. Upon displacement of blocker DNA by target DNA or cleavage by restriction endonuclease, G-DNAzymeMB is released and two lateral portions of G-DNAzymeMB form a G-quadruplex structure, resulting in the recovery of catalytic activity which acts as a cofactor to catalyze H(2)O(2)-mediated oxidation of H(2)DCFDA. For DNA detection system, exonuclease III (Exo III)-catalyzed amplification strategy is introduced to improve the sensitivity and target DNA could be detected as low as 0.1 pM. With respect to restriction endonuclease detection system, 0.1 U/mL EcoRI endonuclease could be detected and this method could be easily transported to other restriction endonuclease analysis by simply changing the recognition sequence. These results demonstrate that the proposed G-DNAzymeMB strategy could be used as a label-free, simple, sensitive and cost-effective approach in analysis of target DNA and restriction endonuclease.

Determination of N¹,N¹²-diacetylspermine in urine: a novel tumor marker

N¹,N¹²-diacetylspermine (DiAcSpm) is a minor component of human urine that constitutes less than 0.5% of total polyamine species in human urine. Structurally related polyamines and acetylpolyamines were separated and analyzed by HPLC and gas chromatography, and refinement of these procedures led to the identification of this minor component. Subsequent analyses of urines from cancer patients as well as healthy persons revealed that DiAcSpm is a promising candidate for a novel tumor marker. It is much more sensitive than established tumor markers in detecting colorectal and other cancers, and most importantly, is able to detect 60% of early colorectal cancers confined to mucous membranes. Serum CEA is able to detect only about 10% of colorectal cancers at this stage. Collection of urine is easy and does not give any pain to patients, which adds another merit to urinary DiAcSpm as a tumor marker. DiAcSpm-specific antibodies were then developed for simpler determination of DiAcSpm in urine, and the antibodies were used to construct an ELISA system. More recently, a reagent kit for DiAcSpm determination based on colloidal gold aggregation that can be used with automatic biochemical analyzers was also developed.

A simple, universal colorimetric assay for endonuclease/methyltransferase activity and inhibition based on an enzyme-responsive nanoparticle system

An enzyme responsive nanoparticle system that uses a DNA-gold nanoparticle (AuNP) assembly as the substrate has been developed for the simple, sensitive, and universal monitoring of restriction endonucleases in real time. This new assay takes advantage of the palindromic recognition sequence of the restriction nucleases and the unique optical properties of AuNPs and is simpler than the procedure previously described by by Xu et al. (Angew. Chem. Int. Ed. Engl. 2007, 46, 3468-3470). Because it involves only one type of ssDNA modified AuNPs, this assay can be directed toward most of the endonucleases by simply changing the recognition sequence found within the linker DNA. In addition, the endonuclease activity could be quantitatively analyzed by the value of the reciprocal of hydrolysis half time (t(1/2)(-1)). Furthermore, our new design could also be applied to the assay of methyltransferase activity since the methylation of DNA inhibits its cleavage by the corresponding restriction endonuclease, and thus, this new methodology can be easily adapted to high-throughput screening of methyltransferase inhibitors.

Diacetylated derivatives of spermine and spermidine as novel promising tumor markers

N1,N12-diacetylspermine (DiAcSpm) and N1,N8-diacetylspermidine (DiAcSpd) are minor components of human urinary polyamine to which little attention has been paid until recently. HPLC analysis of urinary polyamines has revealed that the excretion of these diacetylpolyamines, in particular, into urine was frequently and markedly increased in association with every type of cancer so far examined. Remission was usually accompanied by recovery of urinary diacetylpolyamines to the normal level. DiAcSpm was more sensitive than CEA for detecting colorectal cancer patients, while DiAcSpd was highly specific for malignant conditions in that the excretion of the latter was scarcely elevated in cases of benign urogenital diseases. An ELISA procedure for rapid determination of DiAcSpm was developed to promote the clinical application of these new tumor markers, and subsequent studies indicated that DiAcSpm was elevated in 60% of colorectal cancer patients at early stages (stage 0 + I), whereas only 10% of these patients were CEA-positive. DiAcSpm may also be useful as a follow-up marker that is efficient for detecting recurrence and sensitive to changes in the clinical condition of patients. The evidence accumulated so far indicates that DiAcSpm and DiAcSpd are promising novel tumor markers. They deserve more intensive studies, including studies of their biochemistry and metabolism.

Regulation of Polyamine and Cancer

This review describes my work in the field of polyamine research for the last 35 years. My research started with developing the improved synthesis of decarboxylated S-adenosylmethionine and then moved to the purification of spermidine synthase from rat prostate. I also took considerable efforts to find the synthetic procedure for various polyamines with high yield in order to prepare (15)N-labeled polyamines. On the basis of these methodological work, I searched for the inhibitor of spermidine synthase and found trans-4-methylcyclohexylamine (MCHA), the most effective one at the present time. I also developed a new analytical method for polyamines using stable isotope and ionspray ionization mass spectrometry (IS-MS). Based on these studies I examined the role of polyamines in liver regeneration and found that oral administration of MCHA effectively changed the concentration of polyamines and inhibited the hepatic growth. I also found the close relationship between the concentration ratio of spermidine to spermine and the extent of liver regeneration. These results may shed new light on the control of cell growth by polyamine in vivo.

Interaction of N1,N12-diacetylspermine with polyamine transport systems of polarized porcine renal cell line LLC-PK1

LLC-PK(1) cells grown on porous membrane filters were employed as a model system to explore the renal transport of polyamines. The polarity of LLC-PK(1) monolayers was confirmed by the exclusive appearance of a Na(+)-dependent alpha-methylglucoside transport system on the apical surface. The uptake of free polyamines from the basolateral side of monolayers was consistent with the existence of a single class of transport system, while the existence of two kinetically distinct polyamine transport systems with higher and lower affinities on apical membranes was suggested. The results of competition studies indicated that each of these transporters was able to interact with putrescine, spermidine and spermine. LLC-PK(1) cells incorporated monoacetylspermine from the apical surface of monolayers at about half the rate of spermine uptake. Monoacetylspermine inhibited spermidine uptake, indicating that free polyamine transport systems also recognized the monoacetylated derivative. In contrast, N(1),N(12)-diacetylspermine did not inhibit spermidine uptake, nor was it incorporated into the cells, indicating the absence of transport systems that recognize N(1),N(12)-diacetylspermine on the apical membranes of LLC-PK(1) cells. These results may be relevant as to our previous observation that the content of diacetylpolyamines in urine is relatively constant, and may explain the excellence of N(1),N(12)-diacetylspermine as a tumor marker.

N(1),N(12)-Diacetylspermine as a sensitive and specific novel marker for early- and late-stage colorectal and breast cancers

PURPOSE

N(1),N(12)-diacetylspermine (DiAcSpm) in the urine of colorectal and breast cancer patients was examined to establish its usefulness as a novel diagnostic tool for detecting these cancers at clinically early stages.

EXPERIMENTAL DESIGN

Urine samples from 248 colon cancer patients and 83 breast cancer patients as well as 51 patients with benign gastrointestinal diseases treated in Tokyo Metropolitan Komagome Hospital during the period of August 1999 to January 2004 were collected. DiAcSpm was analyzed by ELISA and its sensitivity for malignant conditions was compared with that of serum carcinoembryonic antigen (CEA), CA19-9, and CA15-3.

RESULTS

The sensitivity of urinary DiAcSpm for colon cancer patients (n = 248) was 75.8% (mean +/- 2 SD for 52 healthy controls as a cutoff value), which was markedly higher than the sensitivities of serum CEA (39.5%, P < 0.0001) and CA19-9 (14.1%, P < 0.0001). DiAcSpm was elevated in 60% of tumor-node-metastasis cancer stage 0 + I patients, whereas only 10% (P < 0.0001) and 5% (P < 0.0001) of these patients were CEA- and CA19-9-positive, respectively. The sensitivity of urinary DiAcSpm for 83 cases of breast cancer (60.2%) was higher than the sensitivities of CEA (37.3%, P = 0.0032) and CA15-3 (37.3%, P = 0.0032). DiAcSpm was elevated in 28% of tumor-node-metastasis stage I + II patients, whereas only 3% (P = 0.0064) and 0% (P = 0.001) of these patients were CEA- and CA15-3-positive, respectively.

CONCLUSION

The observations indicate that urinary DiAcSpm is a more sensitive marker than CEA, CA19-9, and CA15-3 and that it can efficiently detect colorectal and breast cancers at early stages.

Determination of polyamines in human tissues by precolumn derivatization with 9-fluorenylmethyl chloroformate and high-performance liquid chromatography

A high-performance liquid chromatography (HPLC) assay with fluorescence detection was developed for the determination of the polyamines putrescine, spermidine, spermine in samples of human spinal cord, cerebellum, cerebrospinal fluid (CSF), skeletal muscle, and muscle microdialysates without an extensive sample preparation. The precolumn derivatization was performed with 9-fluorenylmethyl chloroformate (FMOC), and the derivatizated polyamines were stable for at least 14 h at 4 degrees C. All polyamines were separated within 35 min. The method was checked for linearity, and mean correlation coefficient values of 0.995, 0.999, and 0.991 were achieved for putrescine, spermidine, and spermine, respectively. The within- and between-assay coefficient of variation percentages evaluated in standard solutions varied between 1.0 and 4.9% and between 1.3 and 6.9%, respectively. The corresponding values obtained in samples of human spinal cord were between 1.0 and 5.0% and between 0.6 and 5.8%. The values of the recovery, evaluated in spinal cord tissue, varied between 83.7 and 93.5%.

Urine diacetylspermine as a novel tumour maker for pancreatobiliary carcinomas

BACKGROUND

Serum carcinoembryonic antigen (highly specific) and carbohydrate antigen 19-9 (highly sensitive) have been used as tumour markers for pancreatobiliary cancers. A novel urine tumour marker, diacetylspermine, was compared with the two conventional serum tumour markers in 125 patients with pancreatobiliary diseases.

RESULTS

When the diagnosis of benign or malignant condition was examined, the sensitivity of urine diacetylspermine (75%) was higher than that of serum carcinoembryonic antigen (44%; P=0.048) and the same as that of serum carbohydrate antigen 19-9 (75%). The specificity of urine diacetylspermine (81%) was lower than that of serum CEA (92%) and as high as that of serum carbohydrate antigen 19-9 (80%). The efficiency of urine diacetylspermine (79%) was higher than that of serum carcinoembryonic antigen (74%) and the same as that of serum carbohydrate antigen 19-9 (79%).

CONCLUSION

These results suggest that urine diacetylspermine is a marker for pancreatobiliary carcinoma, which is as highly sensitive and specific as serum carbohydrate antigen 19-9.

Analysis of polyamines as markers of (patho)physiological conditions

The aliphatic polyamines, putrescine, spermidine and spermine, are normal cell constituents that play important roles in cell proliferation and differentiation. The equilibrium between cellular uptake and release and the balanced activities of biosynthetic and catabolic enzymes of polyamines are essential for normal homeostasis in the proliferation and functions of cells and tissues. However, the intracellular polyamine content increases in hyperplastic or neoplastic growth. Although the involvement of polyamines in physiological and pathological cell proliferation and differentiation has been well established, the role they play is quite different in relation to cell systems and animal models and is dependent on inducer agents and stimuli. Also, the experimental procedures used to deplete polyamines have been shown to influence the cell responses. In this paper, the assay methods currently in use for polyamines are reviewed and compared with respect to sensitivity, reproducibility and applicability to routine analysis. The relevance of polyamine metabolism and the uptake/release process in many physiological and pathological processes is highlighted, and the cellular polyamine pathways are discussed in relation to the possible diagnostic and therapeutic significance of these mediators.

Mass spectrometric separation and determination of N1,N12-diacetylspermine in the urine of cancer patients

An ionspray ionization mass-spectrometric method for the determination of N1,N12-diacetylspermine (Ac2Spm) was developed using 15N-labeled Ac2Spm as the internal standard. Concentrations of Ac2Spm in the urine obtained from 17 cancer patients measured by the present method correlated well with those measured by ELISA, showing the usefulness of the two methods.

Clinical role of polyamine analysis: problem and promise

Polyamines are ubiquitous cell components for growth. They play an important role in cell proliferation, cell growth and synthesis of protein and nucleic acids. Cells that are stimulated to reproduce demonstrated early increases in biosynthetic enzymes involved in polyamine synthesis and subsequent elevations in polyamine levels. Extracellular fluid polyamine concentrations that reflect the intracellular events may be useful as rapid indicators of therapy in disorders which involve altered cell growth. More complex analytical approaches are required to isolate, identify and quantitate these polyamines. Most of the methods require an extraction procedure to remove interfering amino acid derivatives. Daily monitoring of plasma and urine polyamine levels in many pathological states may provide a non-invasive biochemical marker of the existing disease activity or response to therapy or to screen for drug efficacy. Automated high-performance liquid chromatography, with post or pre-column derivatization and fluorescence or electrochemical detection is frequently used for the simultaneous quantitation of picomolar quantities of polyamines. Recently, a new immuno-cytochemical model system incorporating an enzyme-linked immunosorbent assay for specific polyamines has been developed. The increasing momentum of basic science information in the polyamine discipline may lead clinicians to regard polyamines, their metabolites and antimetabolites as sources of effective treatment.