Lactobacillus rhamnosus GG influences polyamine metabolism in HGC-27 gastric cancer cell line: a strategy toward nutritional approach to chemoprevention of gastric cance.

Chemoprevention by dietary constituents has recently emerged as a novel approach to control gastric cancer incidence. Over the past years, functional foods and food supplements, especially probiotics, have received much attention as potential dietary cancer prevention agents. The precise mechanisms by which these lactic cultures exert their antitumorigenic activities are not fully elucidated, but there is some evidence of their influence on cell proliferation and growth. Ornithine decarboxylase (ODC) and spermidine/spermine N1-acetyltransferase (SSAT) are the key enzymes involved in polyamine biosynthesis and catabolism, respectively. These polycationic compounds are significantly associated with cancer risk and represent a specific markers for neoplastic proliferation. The aim of this study was to investigate the effects of increasing concentrations of Lactobacillus rhamnosus strain GG (ATCC 53103) (L. GG) homogenate on polyamine biosynthesis and polyamine degradation as well as on resulting polyamine levels in HGC-27 human gastric cancer cells. The influence of this probiotic on cell proliferation was also evaluated. Administration of probiotic homogenate significantly reduced both ODC mRNA and activity as well as polyamine content and neoplastic proliferation. Besides, an increase in both SSAT mRNA and activity occurred after LGG administration in HGC-27. These data suggest that a nutritional component such as the probiotic L. GG could be proposed in an alternative approach to prevention of gastric cancer. This strategy could overcome the limitations due to a prolonged use of drugs and/or the occurrence of their adverse effects, and it could reasonably also start at a young age.

Polyamine biosynthesis in relation to K-ras and p-53 mutations in colorectal carcinoma.

BACKGROUND: Polyamines are important polycations found in high concentrations in gastrointestinal neoplasms, and ornithine decarboxylase is the key enzyme in their biosynthesis. Also genes with oncogenic potential (e.g. K-ras and p53) contribute to neoplastic transformation by modifying normal cellular proliferation and differentiation. Our aim was to evaluate the ornithine decarboxylase activity and polyamine levels in samples of colorectal carcinoma and uninvolved surrounding mucosa from 86 patients (52 men and 34 women) showing different patterns of K-ras/p53 mutations. METHODS: Polyamines were evaluated by high performance liquid chromatography. Ornithine decarboxylase activity was determined using the radiometric method. K-ras and p53 mutations were investigated by PCR followed by restriction fragment length polymorphism (PCR-RFLP) and single strand conformational polymorphism (PCR-SSCP), respectively. Multiple linear regression analysis was used to analyse relationships among polyamine biosynthesis, clinical-pathological variables and K-ras/p53 mutations. RESULTS: ODC activity and polyamine levels were significantly higher in neoplastic samples than in normal surrounding mucosa. K-ras codon 12 mutation was found in 25/86 patients (29.1%) and p53 gene mutation in 41/86 (47.7%). Polyamine biosynthesis was significantly higher in cancers showing K-ras mutation, either with or without p53 mutation [K-ras(+)/p53(-) and K-ras(+)/p53(+)], compared to samples with K-ras wild type [K-ras(-)/p53(-) and K-ras(-)/p53(+)]. Multiple linear regression analysis confirmed this finding. CONCLUSIONS: The present study provides evidence of a close relationship between K-ras mutation and polyamine biosynthesis in human colorectal carcinoma in a way that is largely p53 independent. In addition, our data support the hypothesis of different pathways in colorectal tumorigenesis reflecting different combinations of biochemical parameters and genetic alterations.

Estrogens and colorectal cancer.

In recent years, several lines of epidemiologic, clinical and experimental evidences have been reported showing that estrogen hormones may be involved in malignant colorectal tumors. The sex differences in site-specific incidence, the increased incidence of colonic cancer in women with breast cancer, the protective effect of increasing parity and the reduced risk among women taking postmenopausal hormones, are all elements suggesting that sex hormones may play a role. Male rats experimentally exposed to the carcinogen dimethylhydrazine, have twice the risk of developing colon cancer and significantly shorter survival times than their female counterparts. Along with the clinical, experimental and epidemiologic findings there are also biologic reasons why estrogen may be protective. Most estrogen action appears to be exerted via the estrogen receptors (ERs) on target cells. ERs have been reported in several solid tumors including gastrointestinal neoplasms such as esophageal, gallbladder, gastric and colorectal cancer. At the end of 1995, a second ER (ER-beta) was cloned from the rat prostate cDNA library and subsequently, the human and mouse homologs. Its demonstration in normal and neoplastic human colorectal tissues and "in vitro" in colonic epithelial cells, has renewed interest in investigating the existence of two ER subtypes. The presence of two ERs could explain the selective actions of estrogens on different target tissues and, particularly, on the gastrointestinal tract. Finally, our studies suggest that estrogens and their receptors play an important role in the growth and progression of colorectal tumors, by interacting with other molecules required for cell proliferation like growth factors and polyamines.

Effects of 17beta-estradiol administration on apoptosis and polyamine content in AGS cell line.

BACKGROUND: Estrogens and polyamines seem to play an important role not only in cell growth and differentiation, but also in programmed cell death. The aim of the present study was to investigate the effects of 17beta-estradiol supplementation on apoptosis as well as on the polyamine content of an ER-positive human gastric cancer cell line (AGS). MATERIALS AND METHODS: Apoptosis was investigated by evaluating DNA fragmentation, using enzyme immunoassay and agarose gel electrophoresis and the phosphatidylserine exposure by flow cytometry analysis. Polyamine levels were evaluated by HPLC. RESULTS: 17Beta-estradiol gave rise to a marked pro-apoptotic effect at concentrations of 16 microM or higher compared to the control. Moreover, the hormone significantly reduced the contents of polyamines compared to control cells. The apoptotic effect of 17beta-estradiol was partially counteracted by exogenous spermine administration. CONCLUSION: 17Beta-estradiol administration induces apoptosis in AGS cells. Further, an increase in cell sensitivity to apoptosis due to a decline in the polyamine content may be suggested.

Erythrocyte polyamines and prognosis in colorectal cancer patients.

BACKGROUND: Polyamines play a role in cell proliferation and in cancer development: they are mainly carried by red blood cells (RBCs). Abnormally high polyamine levels in RBCs have been demonstrated in patients with various types of cancer and the prognostic value of RBC polyamine levels has also been underlined. Our aims were to compare polyamine levels in RBCs from colorectal adenocarcinoma (CRA) patients with those from non neoplastic patients and to evaluate the prognostic value of pre-treatment polyamine erythrocyte levels. PATIENTS AND METHODS: Sixty-one patients with colorectal cancer and 28 surgical patients affected by non neoplastic diseases were included in this study. RBCs polyamine levels were evaluated by HPLC. RESULTS: Significantly higher spermidine, spermine and total polyamine levels were found in RBCs from CRA patients compared to those from control patients. However, there was no significant difference in the survival of patients with different polyamine levels. CONCLUSION: Our findings show that RBC polyamine levels are not a biologic parameter that may help to discriminate between good and poor prognosis in colorectal cancer patients.

Duodenogastric reflux and gastric mucosal polyamines in the non-operated stomach and in the gastric remnant after Billroth II gastric resection. A role in gastric carcinogenesis?

BACKGROUND: The relationship between bile reflux and gastric cancer is not defined. In order to verify whether a relationship exists, we evaluated the duodenogastric reflux and the mucosal polyamines concentration, polycation compounds actively involved in cell proliferation, in the non-operated stomach and in gastric remnant after Billroth II gastric resection, a precancerous condition. MATERIALS AND METHODS: The study was performed on three groups of subjects: A) 43 subjects with slight dispeptic symptoms, never operated on; B) 54 cholecystectomized subjects; C) 38 subjects operated on Billroth II gastric resection for duodenal ulcer. Duodenogastric reflux was assessed by measuring the concentration of bile acids in gastric juice and expressed as Fasting Bile Reflux in micromol/hour. Gastric mucosal polyamine concentration was assessed by High Performance Liquid Chromatography and expressed in nmol/mg of proteins. RESULTS: The lowest levels of Fasting Bile Reflux (7.95 micromol/hour) and polyamines (7.09 nmol/mg proteins) were observed in subjects never operated on. The middle values were present after cholecystectomy (Fasting Bile Reflux = 18 micromol/hour; polyamines = 8.14 nmol/mg proteins). The highest values were observed after Billroth II gastric resection (Fasting Bile Reflux = 830 micromol/hour; polyamines 11.74 nmol/mg proteins) (Kruskal-Wallis test, p = 0.0001). There was a positive correlation between Fasting Bile Reflux and polyamines (Spearman's rank = 0.33; p = 0.0008). CONCLUSIONS: High levels of duodenogastric reflux observed after Billroth II gastric resection are associated with high polyamine concentration in the gastric mucosa. Bile reflux can be considered an important causal factor of the increased risk of gastric stump cancer after Billroth II gastric resection.

Helicobacter pylori infection and host cell responses.

It is well known that Helicobacter pylori is able to colonize the gastric mucosa, causing a chronic and persistent infection with complications, such as peptic ulcer and gastric cancer. This review places emphasis on some epidemiological aspects of Helicobacter pylori infection and its mode of transmission. At the same time, invasive and non-invasive methods of diagnosis of Helicobacter pylori infection are illustrated. More space is devoted to the host response following invasion of the stomach. In this respect, the role played by different growth factors and polyamines in the course of Helicobacter pylori disease is discussed also in relation to the result of eradicating treatment. On the other hand, an accurate description of the host immune responses against Helicobacter pylori organism and/or their components (e.g. lipopolysaccharides) is reported. Finally, since Helicobacter pylori has been classified as a class I carcinogen, current researches are focussed on the Helicobacter pylori-induced carcinogenesis.

Relationship among red blood cell polyamine content, phagocytic activities and plasma endotoxins in untreated colorectal cancer patients.

Polyamines are actively involved in immune processes and it is known that patients with cancer often exhibit immune deficits. Twenty-two patients with colorectal cancer were enrolled into this study, before starting conventional treatments. The relationship among the content of polyamines in red blood cells and phagocytosis and killing of monocytes and polymorphonuclear cells, and endotoxemia was investigated. The data show a negative correlation among levels of total polyamines and spermine and monocyte phagocytosis. Higher levels of spermine were present in patients with detectable circulating endotoxins. Our findings suggest a down-modulating effect of polyamines on the monocyte phagocytosis in untreated colorectal cancer patients; this effect could explain the presence of circulating endotoxins in cancer bearing patients.

Inhibitory effect of 17beta-estradiol on growth and the polyamine metabolism of a human gastric carcinoma cell line (HGC-27).

BACKGROUND: Estrogens may, by means of their receptors, modulate the growth of several tumors including gastrointestinal neoplasms. This control may occur through interaction with other molecules such as polyamines. An inverse relation between polyamine levels and the estrogen receptorial content has previously been demonstrated in vivo in human gastric carcinoma. The aim of the present study was to evaluate the effects of 17beta-Estradiol administration on the in vitro cell proliferation rates and the polyamine metabolism of an estrogen receptor-positive human gastric cancer cell line (HGC-27). METHODS: Estrogen receptors were detected with enzyme immunoassay. Cell proliferation was assessed by means of [3H]-thymidine incorporation and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. The polyamine content was evaluated with high-performance liquid chromatography and the ornithine decarboxylase activity with a radiometric technique. RESULTS: Exposure of HGC-27 cells to increasing concentrations of 17beta-Estradiol showed that an antiproliferative action became evident at concentrations of 8 microM or higher. At such concentrations, ornithine decarboxylase (ODC) activity was also significantly reduced, as were all polyamine levels, compared with the untreated control. These findings suggest that one of the mechanisms underlying 17beta-Estradiol inhibition of HGC-27 cell proliferation is a decrease in ODC activity and, hence, in polyamine production.

Polyamine profile in human gastric mucosa infected by Helicobacter pylori.

BACKGROUND: Several studies have demonstrated increased gastric epithelial cell proliferation associated with Helicobacter pylori infection, which is reversed after bacterium eradication. Among the substances involved in cell proliferation and differentiation, polyamines are a group of polycations found in high concentrations both in normal and neoplastic cells. AIMS: Of the study were: a) to examine the influence of Helicobacter pylori infection on the polyamine profile in the gastric antrum and body, by comparing infected, to uninfected, patients, b) to evaluate the effect of successful and unsuccessful bacterium eradication on polyamine levels. PATIENTS AND METHODS: Twenty-six consecutive dyspeptic patients (20 Helicobacter pylori positive and 6 Helicobacter pylori negative) undergoing gastroscopy were enrolled. Polyamines were evaluated in antral and body biopsies by High Performance Liquid Chromatography. RESULTS: Antral and body biopsies from Helicobacter pylori positive patients contained higher polyamine levels than those from Helicobacter pylori negative subjects. In Helicobacter pylori positive patients, the baseline polyamine levels were higher in the antrum than in the body. In Helicobacter pylori negative subjects, levels in the two stomach regions were similar. After therapy, polyamine levels decreased in patients with successful eradication, whereas these levels remained unchanged in patients in whom infection persisted. CONCLUSIONS: These findings indicate enhanced antral cellular proliferation linked to the presence of Helicobacter pylori and add weight to the postulation of an association between Helicobacter pylori infection and increased risk of neoplastic changes in gastric antral mucosa. Differences in antral and body levels of polyamines may also be considered as a further indication of the different mucosal reactivity between the two regions of the stomach towards bacterial invasion.

Polyamine levels and ODC activity in intestinal-type and diffuse-type gastric carcinoma.

Gastric carcinomas are divided into two types according to Lauren's classification: intestinal and diffuse types. Polyamines (putrescine, spermidine, and spermine) are polycations involved in neoplastic growth of gastrointestinal mucosa. A key role is also played by ornithine decarboxylase, the rate limiting enzyme in polyamine metabolism. Our aim was to investigate whether there were differences between the two types of tumor in polyamine metabolism. Twenty-seven patients with gastric carcinoma entered the study. Seventeen carcinomas were classified as diffuse type and 10 as intestinal type. Polyamine levels were evaluated by high-performance liquid chromatography. Ornithine decarboxylase activity was measured by a radiometric technique. Polyamine levels and ornithine decarboxylase activity were significantly higher in intestinal type samples than diffuse type samples. A similarity of polyamine levels in intestinal type samples with levels previously observed in patients with colorectal adenocarcinoma was also found. These findings show a different proliferative behavior of these two types of tumor, and therefore different therapeutic strategies can be hypothesized.

Polyamine oxidase activity and polyamine levels in human colorectal cancer and in normal surrounding mucosa.

BACKGROUND: Polyamine oxidase (PAO) is an enzyme involved in the interconversion pathway of polyamines, compounds required for cell proliferation and differentiation. As the role of PAO in tumor growth is unclear, and no data about PAO activity in human colorectal carcinoma are available, our aim was to investigate PAO activity and polyamine levels in this kind of tumor. METHODS: Polyamine levels and PAO activity were detected in 30 neoplastic colorectal samples and surrounding mucosa by HPLC. RESULTS: Free and N1-acetylated polyamine levels were higher in the neoplastic tissue than surrounding mucosa of the same patient. On the contrary, PAO activity was significantly lower in the neoplastic tissue than surrounding mucosa. CONCLUSION: It seems that PAO activity does not play an important role in the increased free polyamine levels in human colorectal carcinoma. Instead, the low PAO activity observed in our study let us to hypothesize that polyamine analogues can have an antitumoral effect on colorectal carcinoma.

Low density lipoprotein receptors and polyamine levels in human colorectal adenocarcinoma.

The low density lipoprotein receptor (LDLR) is a cell surface protein that binds with LDL, providing the cell with cholesterol for new membrane synthesis. Rapidly growing cells have high numbers of LDLRs, and these proteins have also been detected in neoplastic samples of human colorectal mucosa. Polyamines, putrescine, spermidine, and spermine, play an important role in cellular growth, and studies on colorectal cancers have demonstrated higher polyamine levels in neoplastic mucosa samples than in surrounding mucosa. The aim of this study was to investigate LDLR and polyamine levels in the neoplastic tissue of 43 patients (28 males and 15 females) with colorectal adenocarcinoma, using enzymatic immunoassay and high performance liquid chromatography, respectively. Specimens of neoplastic mucosa were considered LDLR-positive or LDLR-negative when the amount of bound human anti-LDLR antibody detected was equal or higher or lower than the cut-off value (0.5 ng of bound anti-LDLR Ab/mg protein), respectively. Twenty-one subjects were LDLR-positive and 22 LDLR-negative. Polyamine levels (nmol/g tissue) were higher in LDLR-positive specimens; this increase was significant for total polyamines (P < 0.05). These findings, reporting the presence of increased polyamine content in LDLR-positive colorectal neoplastic specimens, suggest an association between LDLR levels and gastrointestinal neoplastic proliferative activity.

Duodenogastric reflux, histology and cell proliferation of the gastric mucosa before and six months after cholecystectomy.

In order to evaluate the effects that an increase in duodenogastric reflux (DGR) has on the mucosal cell proliferation of the non-operated stomach, we made a prospective study on 13 patients (9 female and 4 male, mean age 52 years) both before and 6 months after cholecystectomy, an operation which determines a significant increase in DGR with an intact pyloric sphincter. DGR was evaluated by measuring total intragastric bile acids (dosed by an enzymatic method), and single intragastric bile acids (dosed by High Performance Liquid Chromatography) and it was expressed as Fasting Bile Reflux (FBR) in mumol/h. Gastric cell proliferation was evaluated by measuring (by High Performance Liquid Chromatography) polyamine (putrescine, spermidine and spermine) levels in biopsy specimens taken from the antrum and gastric body. The histology of the antrum and gastric body was also evaluated. After cholecystectomy, there was a significant increase in DGR (delta = 39.23 mumol/h, 95% C.L. 11.69-136.22, sign-test for matched pairs p = 0.0003). The tissue concentration of putrescine in the antrum increased significantly (delta = 8.36 mumol/g of tissue, 95% C.L. 0.34-18.01, sign-test for matched pairs p = 0.013) and there was a worsening of histological findings in the antrum (preoperative chronic atrophic gastritis rate 38.5%, postoperative 69%). In the body there were no significant variations either in polyamine levels or in histology. The increase in DGR and in putrescine concentrations in the antrum were associated negatively (Spearman's rank -0.64, 95% C.L. -0.88 to -0.14).(ABSTRACT TRUNCATED AT 250 WORDS)

Duodenogastric reflux and gastric mucosal cell proliferation after cholecystectomy or Billroth II gastric resection.

OBJECTIVES AND METHODS: Twelve patients to be undergone cholecystectomy and 4 patients to be undergone Billroth II gastric resection were examined before and after surgery in order to evaluate the association between duodenogastric reflux and gastric mucosal cell proliferation. Duodenogastric reflux was assessed by measuring the concentration of bile acids in gastric juice and expressed as fasting bile reflux in mumol/h. Gastric mucosal cell proliferation was assessed by measuring the concentration of polyamines (putrescine, spermidine and spermine) in biopsy specimens and expressed in mumol/g of tissue. RESULTS: The median increase in fasting bile reflux was 34 mumol/h after cholecystectomy and 238 mumol/h after Billroth II gastric resection (P = 0.008). After cholecystectomy the median value of putrescine levels in antrum was 39 mumol/g, whereas after Billroth II gastric resection putrescine levels in pre-anastomotic area was 79.5 mumol/g (P = 0.008). There was a positive correlation between fasting bile reflux and putrescine levels either in antrum (r = 0.37, P = 0.04) or body (r = 0.48, P = 0.006). CONCLUSIONS: The increase in cell proliferation activity of gastric mucosa after Billroth II gastric resection might explain the increased risk for cancer of gastric remnant.

Estrogen receptors and polyamine levels in human gastric carcinoma.

We evaluated polyamine (putrescine, spermidine, and spermine) levels, estrogen receptor concentrations, and their relationship in neoplastic tissue and surrounding mucosa from 30 patients with gastric adenocarcinoma. Cytosolic estrogen receptors were measured with an immunoenzymatic assay. Polyamine levels were evaluated with high-performance liquid chromatography. Estrogen receptor concentrations were statistically higher in surrounding mucosa than in neoplastic tissue (p = 0.023). Putrescine and spermidine levels and the spermidine to spermine ratio were statistically higher in neoplastic tissue than in surrounding mucosa (p < 0.004). Significant correlations were found between the levels of spermidine and total polyamines in neoplastic tissue and surrounding mucosa (r = 0.48, p = 0.014, and r = 0.45, p = 0.021, respectively). Polyamine levels were lower in estrogen-receptor-positive tumors than in estrogen-receptor-negative ones, although this decrease was statistically significant only in the case of spermine (p = 0.02). The significance of these findings is that the cellular activity of normal and neoplastic gastric mucosa may be partly controlled by estrogens.

Polyamines, diamine oxidase, and ornithine decarboxylase activity in colorectal cancer and in normal surrounding mucosa.

We investigated the polyamine levels [putrescine (Put), spermidine (Spd), and spermine (Spm)] and their metabolism by simultaneously considering the ornithine decarboxylase (ODC) and diamine oxidase (DAO) activities in human colorectal cancer and in normal surrounding tissue. Single and total polyamine levels were significantly higher in the neoplastic tissue than in the surrounding mucosa from the same patients. Furthermore, the ODC activity was significantly higher and the DAO activity significantly lower in the neoplastic tissue than in the surrounding mucosa. Polyamine levels and enzymatic activities did not correlate with the clinical and histologic characteristics of patients. In normal tissue samples, no correlation was found between single and total polyamine levels and enzymatic activities (both DAO and ODC). On the contrary, in colorectal neoplastic samples, significant and positive correlations were found between the levels of total polyamines, Spd, and Spm and the ODC activity. In the same specimens, DAO activity was related to Spd levels and the Spd/Spm ratio, but, in those cases, the correlation was negative. Thus, our findings suggest that, during the neoplastic growth of the colorectal mucosa, the balance between polyamine degradation and biosynthesis is disengaged from the control exerted by the two enzymes.

Sex steroid hormone receptors, epidermal growth factor receptor, and polyamines in human colorectal cancer.

We assayed the estrogen and progesterone cytosolic receptors by using the enzyme immunoassay method, the epidermal growth factor (EGF) cell surface receptors by using 125I-labeled hormone, and the levels of polyamines (putrescine, spermine, and spermidine) by using a high-pressure liquid chromatography (HPLC) procedure in neoplastic and surrounding normal tissues of patients with colorectal cancer. Our findings show that mean polyamine levels in neoplastic tissue were approximately two-fold greater than the levels in normal colonic mucosa. Estrogen and progesterone receptorial content in normal mucosa were twofold greater than those in neoplastic tissue. No significant differences in EGF receptors were found between colonic cancer tissue and the surrounding normal tissues. The correlations we found between 1) estrogen and polyamine levels and 2) estrogen and EGF binding suggest the existence of a modulation of the estrogens on colonic mucosa cell proliferation. Furthermore, there was no significant dependency of polyamine and receptor concentrations from the tumor site, the histologic differentiation, or the age and sex of patients.

Polyamines and estrogen-receptor concentrations in human colorectal carcinomas.

We assayed the estrogen receptors and polyamine levels (putrescine, spermidine and spermine) in the neoplastic and "normal" surrounding tissue of patients with colorectal cancer. Polyamine levels and the spermidine/spermine ratio were significantly higher in the neoplastic tissue than in the "normal" surrounding colonic mucosa of the same patients. Estrogen receptors were fewer in neoplastic mucosa than in the surrounding tissue, and polyamine levels were higher in estrogen-receptor negative tumours than in estrogen-receptor positive ones, although this was statistically significant only in the case of spermidine. Polyamine levels and estrogen receptor concentrations did not correlate with the tumour site, histological differentiation, or the age and sex of patients.