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

Crosstalk between the B7/CD28 and EGFR pathways: Mechanisms and therapeutic opportunities

Somatic activating mutations in the epidermal growth factor receptor (EGFR) are one of the most common oncogenic drivers in cancers such as non-small-cell lung cancer (NSCLC), metastatic colorectal cancer, glioblastoma, head and neck cancer, pancreatic cancer, and breast cancer. Molecular-targeted agents against EGFR signaling pathways have shown robust clinical efficacy, but patients inevitably experience acquired resistance. Although immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 have exhibited durable anti-tumor responses in a subset of patients across multiple cancer types, their efficacy is limited in cancers harboring activating gene alterations of EGFR. Increasing studies have demonstrated that upregulation of new B7/CD28 family members such as B7-H3, B7x and HHLA2, is associated with EGFR signaling and may contribute to resistance to EGFR-targeted therapies by creating an immunosuppressive tumor microenvironment (TME). In this review, we discuss the regulatory effect of EGFR signaling on the PD-1/PD-L1 pathway and new B7/CD28 family member pathways. Understanding these interactions may inform combination therapeutic strategies and potentially overcome the current challenge of resistance to EGFR-targeted therapies. We also summarize clinical data of anti-PD-1/PD-L1 therapies in EGFR-mutated cancers, as well as ongoing clinical trials of combination of EGFR-targeted therapies and anti-PD-1/PD-L1 immunotherapies.

Association of Type 1 diabetes with ulcerative colitis in BALB/c mice: Investigations on sex-specific differences

Diabetes comorbidity in ulcerative colitis (UC) has relevant clinical and therapeutic implications. The link between hyperglycemia and intestinal barrier function with respect to infection and inflammation consequences exists in diabetes. The present study was designed to decipher the molecular mechanisms associated with Type 1 Diabetes mellitus and the UC in both male and female BALB/c mice. Dextran sulfate sodium (DSS; 2.5%w/v) dissolved in drinking water was given for three cycles (each cycle; 7 days) with 7 days recovery period in-between to both male and female BALB/c mice. At the first recovery period, Streptozotocin (40 mg/kg; i.p.) was administered for 5 consecutive days in the case of male BALB/c mice; whereas the same procedure was repeated at the beginning of each recovery period in female animals. In the DSS + DB group of male animals, disease activity index, myeloperoxidase activity, nitrite level, plasma lipopolysaccharides, interleukin-1β, histological score, % fibrotic area, % TUNEL positive cells were significantly increased. Furthermore, protein expression of phosphorylated nuclear factor kappa light chain enhancer of activated B cells (pNFκB65), proliferating cell nuclear antigen, interleukin-6, apoptosis-associated speck-like protein containing a caspase-recruitment domain, and cysteine-containing aspartate-specific proteases-1 (caspase-1) significantly increased in the DSS + DB group of male animals as compared to female. The present study findings proved that hyperglycemic conditions exacerbated the pathological conditions in UC of male animals; whereas milder conditions developed in females.

Untargeted Metabolomics and Polyamine Profiling in Serum before and after Surgery in Colorectal Cancer Patients

Colorectal cancer is one of the most prevalent cancers in Korea and globally. In this study, we aimed to characterize the differential serum metabolomic profiles between pre-operative and post-operative patients with colorectal cancer. To investigate the significant metabolites and metabolic pathways associated with colorectal cancer, we analyzed serum samples from 68 patients (aged 20–71, mean 57.57 years). Untargeted and targeted metabolomics profiling in patients with colorectal cancer were performed using liquid chromatography-mass spectrometry. Untargeted analysis identified differences in sphingolipid metabolism, steroid biosynthesis, and arginine and proline metabolism in pre- and post-operative patients with colorectal cancer. We then performed quantitative target profiling of polyamines, synthesized from arginine and proline metabolism, to identify potential polyamines that may serve as effective biomarkers for colorectal cancer. Results indicate a significantly reduced serum concentration of putrescine in post-operative patients compared to pre-operative patients. Our metabolomics approach provided insights into the physiological alterations in patients with colorectal cancer after surgery.

Dietary Polyamines Intake and Risk of Colorectal Cancer: A Case-Control Study

Polyamines (including putrescine, spermidine, and spermine) are small, cationic molecules that are necessary for cell proliferation and differentiation. Few studies have examined the association of dietary polyamines intake with colorectal cancer risk. The aim of this study was to evaluate total polyamines, putrescine, spermidine, and spermine intake in relation to colorectal cancer risk in China. In total, 2502 colorectal cancer cases and 2538 age-(5-year interval) and sex-matched controls were recruited from July 2010 to April 2019. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated by multivariable unconditional logistic regression after adjustment for various potential confounding factors. Higher intake of total polyamine, putrescine and spermidine was significantly associated with reduced risk of colorectal cancer. The adjusted ORs for the highest compared with the lowest quartile of intake were 0.60 (95% CI 0.50, 0.72; P_trend < 0.001) for total polyamines, 0.35 (95% CI 0.29, 0.43; P_trend < 0.001) for putrescine and 0.79 (95% CI 0.66, 0.95; P_trend = 0.001) for spermidine, respectively. However, higher intake of spermine was associated with increased risk of colorectal cancer, with an adjusted OR of 1.58 (95% CI 1.29, 1.93; P_trend < 0.001). This data indicate that higher intake of total polyamines, putrescine and spermidine, as well as lower intake of spermine, is associated with a decreased risk of colorectal cancer.

Ulcerative colitis: From inflammation to cancer. Do estrogen receptors have a role?

Ulcerative colitis (UC) is a condition at increased risk for colorectal carcinoma (CRC) development. Nowadays, screening and follow-up programs are routinely performed worldwide to promote the early detection of CRCs in subjects with well known risk factors (extent, duration and severity of the disorder). The diffusion of these procedures is presumably the main reason for the marked reduction of cancer incidence and mortality in the course of UC. In addition, chemoprevention has been widely investigated and developed in many medical fields, and aspirin has shown a preventive effect against CRC, while mesalazine has been strongly invoked as a potential chemopreventive agent in UC. However, available studies show some limitations due to the obvious ethical implications of drug withdrawal in UC in order to design a control group. The estrogen receptors (ER) alpha/beta balance seems to have a relevant influence on colorectal carcinogenesis and ER beta appears to parallel apoptosis, and hence an anti-carcinogenic effect. Phytoestrogens are compounds acting as ER beta agonists and have shown a promising chemopreventive effect on sporadic as well as genetically inherited CRC. There is evidence suggesting a role for ERs in UC-related carcinogenesis. In this perspective, since these substances can be considered as dietary supplements and are completely free from side effects, phytoestrogens could be an interesting option for CRC prevention, even when the disease is a consequence of long-term chronic inflammation, as in the course of UC. Further studies of their effects are warranted in both the basic research and clinical fields.

Estrogen and progesterone-related gene variants and colorectal cancer risk in women

Background

Observational studies and randomized trials have suggested that estrogens and/or progesterone may lower the risk for colorectal cancer. Inherited variation in the sex-hormone genes may be one mechanism by which sex hormones affect colorectal cancer, although data are limited.

Method

We conducted a comprehensive evaluation of single nucleotide polymorphisms (SNPs) in genes encoding 3 hormone receptors (ESR1, ESR2, PGR) and 5 hormone synthesizers (CYP19A1 and CYP17A1, HSD17B1, HSD17B2, HSD17B4) among 427 women with incident colorectal cancer and 871 matched controls who were Caucasians of European ancestry from 93676 postmenopausal women enrolled in the Women's Health Initiative Observational cohort. A total of 242 haplotype-tagging and functional SNPs in the 8 genes were included for analysis. Unconditional logistic regression with adjustment for age and hysterectomy status was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

We observed a weak association between the CYP17A1 rs17724534 SNP and colorectal cancer risk (OR per risk allele (A) = 1.39, 95% CI = 1.09-1.78, corrected p-value = 0.07). In addition, a suggestive interaction between rs17724534 and rs10883782 in 2 discrete LD blocks of CYP17A1 was observed in relation to colorectal cancer (empirical p value = 0.04). Moreover, one haplotype block of CYP19A1 was associated with colorectal cancer (corrected global p value = 0.02), which likely reflected the association with the tagging SNP, rs1902584, in the block.

Conclusion

Our findings offer some support for a suggestive association of CYP17A1 and CYP19A1 variants with colorectal cancer risk.

Genetic variation in sex-steroid receptors and synthesizing enzymes and colorectal cancer risk in women

OBJECTIVES

Several lines of evidence have suggested that female hormones may lower the risk for developing colorectal cancer. However, the mechanisms by which sex hormones affect colorectal cancer development remain unknown. We sought to determine whether the association may be under genetic control by evaluating genetic variation in estrogen receptors (ESR1 and ESR2), progesterone receptor (PGR), aromatase cytochrome 450 enzyme (CYP19A1), and 17 beta-hydroxysteroid dehydrogenase type 2 gene (HSD17B2).

METHODS

We included 158 incident cases of colorectal cancer and 563 randomly chosen control subjects from 28,345 women in the Women's Health Study aged 45 or older who provided blood samples and had no history of cancer or cardiovascular disease at baseline in 1993. All cases and controls were Caucasians of European descent. A total of 63 tagging and putative functional SNPs in the 5 genes were included for analysis. Unconditional logistic regression was used to estimate odds ratio (ORs) and 95% confidence intervals (CIs).

RESULTS

There was no association between variation in ESR1, ESR2, PGR, CYP19A1 and HSD17B2 and colorectal cancer risk after correction for multiple comparisons (p values after correction > or =0.25). There was also no association with any of the haplotypes examined (p > or = 0.15) and no evidence of joint effects of variants in the 5 genes (p > or = 0.51).

CONCLUSION

Our data offer insufficient support for an association between variation in ESR1, ESR2, PGR, CYP19A1, and HSD17B2 and risk for developing colorectal cancer.

Effects of Lactobacillus rhamnosus GG on proliferation and polyamine metabolism in HGC-27 human gastric and DLD-1 colonic cancer cell lines

Previous in vitro and in vivo studies have suggested that lactobacilli can exert antiproliferative effects on the gastrointestinal epithelium. However, their role in affecting the cellular proliferative mechanisms is not completely clear. The aim of this study was to investigate the effects of increasing concentrations of Lactobacillus rhamnosus strain GG (L. GG) homogenate on cell growth and proliferation (by MTT, [3H]-thymidine incorporation and polyamine biosynthesis) in neoplasms originating from different gastrointestinal tracts. Thus, HGC-27 human gastric cancer cells and DLD-1 human colonic adenocarcinoma cells were evaluated. Besides, in order to verify which bacterial fraction was involved in the antiproliferative effects, the cytoplasm and cell wall extracts were tested separately. Gastric HGC-27 and colonic DLD-1 cells showed significant differences in their proliferative behavior, in particular in their polyamine profile and biosynthesis. Notwithstanding, one and the other proved to be sensitive to the growth inhibition by the highest concentrations of bacterial homogenate. Both HGC-27 and DLD-1 cells were resistant to the bacterial cell wall fractions, whereas increasing cytoplasm fraction concentrations induced an evident antiproliferative effect. These data suggest that cytoplasm extracts could be the responsible for L. GG action on proliferation in these two cell lines from gastric and colonic neoplasms.

Immunohistochemical expression of estrogen and progesterone receptors in primary pulmonary neuroendocrine tumors

CONTEXT

Lung and breast carcinomas are among the most prevalent cancers. Advances in cancer therapies can provide survival benefit and be potentially curative, even in metastatic disease. Due to the high prevalence of these carcinomas, it is not unusual to encounter lung nodule(s) in a patient with breast carcinoma, and distinguishing between primary and metastatic disease is critical for management/treatment. Occasionally neuroendocrine differentiation is present in breast carcinoma, making its distinction from pulmonary/nonpulmonary neuroendocrine tumors in the lung difficult.

OBJECTIVE

To assess estrogen and progesterone receptor expression in the entire spectrum of pulmonary neuroendocrine tumors.

DESIGN

Seventy-one neuroendocrine neoplasms including typical carcinoids (42), atypical carcinoids (7), small cell carcinomas (14), large cell neuroendocrine carcinomas (2), and combined small cell carcinomas (6) were evaluated for estrogen and progesterone receptors. Mammary and non-small cell lung carcinomas were also stained for comparison.

RESULTS

The entire spectrum of neuroendocrine neoplasms demonstrated focal to diffuse estrogen (typical carcinoid, 23; atypical carcinoid, 6; small cell carcinoma, 8; large cell neuroendocrine carcinoma, 2; combined small cell carcinoma, 4) and progesterone (typical carcinoid, 11; atypical carcinoid, 2; small cell carcinoma, 7; large cell neuroendocrine carcinoma, 0; combined small cell carcinoma, 2) expression. There was no correlation between sex and estrogen/progesterone status. Estrogen and progesterone staining were also noted in endothelial cells. Relative to neuroendocrine carcinomas, mammary carcinomas expressed estrogen and progesterone more frequently. Non-small cell carcinomas had greater and similar immunoreactivity for estrogen and progesterone, respectively.

CONCLUSIONS

Although estrogen and progesterone receptor staining is frequently associated with breast and gynecologic primaries, it can also be observed in "nontarget" organs. Therefore, presence of estrogen and/or progesterone expression in neuroendocrine tumors involving the lung should not exclude a primary pulmonary neoplasm.

Oestrogen and the colon: potential mechanisms for cancer prevention

The role of oestrogen in oncogenesis has been examined extensively, especially in the context of breast cancer, and receptor modulators are an integral part of targeted treatment in this disease. The role of oestrogen signalling in colonic carcinoma is poorly understood. Men are more susceptible than women to colon cancer. Furthermore, hormone-replacement therapy affords an additive protective effect for postmenopausal women, and when these women do develop cancer, they typically have less aggressive disease. The discovery of a second oestrogen receptor (ERbeta) and its over expression in healthy human colon coupled with reduced expression in colon cancer suggests that this receptor might be involved. The underlying mechanism, however, remains largely unknown. In this Review, we discuss the various hypotheses presented in the published literature. We examine the cellular and molecular mechanisms through which oestrogen is purported to exert its protective influence, and we review the evidence available to support these claims.

Effects of genistein on the polyamine metabolism and cell growth in DLD-1 human colon cancer cells

Polyamines and their rate-limiting enzyme, ornithine decarboxylase (ODC), are actively involved in cell growth and differentiation. The phytoestrogen genistein has been demonstrated to possess antitumor properties by influencing proliferation, differentiation, and apoptosis. The aim of this study was to investigate the effects of genistein at concentrations ranging from 0.01 to 100 microM on the polyamine biosynthesis, cell proliferation, and apoptosis in the estrogen receptor-positive DLD-1 human colon cancer cell line. Polyamine levels and ODC activity were evaluated by high performance liquid chromatography and radiometric technique, respectively. The proliferative response was estimated by [3H]-thymidine incorporation and the colorimetric 3-(4,5 di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. Apoptosis was investigated by DNA fragmentation. Bax and Bcl-2 gene expressions were evaluated by multiplex-polymerase chain reaction. At concentration >or=1 microM, genistein decreased significantly the ODC activity and the polyamine levels. At the same concentration, genistein also increased significantly Bax mRNA expression, but not Bcl-2 mRNA expression. Higher concentrations (>or=10 microM) were needed to obtain a significant inhibition of cell proliferation and DNA fragmentation. The results of this study suggest that genistein can affect growth of DLD-1 cells by both decreasing polyamine biosynthesis and inducing apoptosis. However, further studies are required to assess the true ability of a soy rich diet in modifying colon cancer risk.

Epidermal growth factor receptor immunohistochemical reactivity in patients with American Joint Committee on Cancer Stage IV colon adenocarcinoma: implications for a standardized scoring system

BACKGROUND

An epidermal growth factor receptor (EGFR) immunohistochemical detection system currently is being developed. The current study attempts to address background EGFR reactivity issues before determining the optimum EGFR scoring system.

METHODS

Tissue sections from 102 patients with T3N1-2M1 colon adenocarcinoma were stained with a prototype EGFR detection system. The number of cases, location, percentage, and intensity of reactive cells (0+ [none] to 3+ [strong]) were scored and compared with the length of survival.

RESULTS

Approximately 75.5% of the adenocarcinoma cases had EGFR reactivity; 31.4% of the tumors had 3+ reactivity in 10-50% of the neoplastic cells and 3.9% had 3+ reactivity in > 50% of cells. Increased numbers of reactive cells per case predominantly resulted from increased 3+ reactivity. The mean percentage of 2+ (moderate) and 3+ reactive cells per case increased in the regions of deepest invasion. The mean percentage of 3+ reactivity per case was significantly greater in the deepest tumor region compared with the superficial region (16.9% vs. 7.9%; P = 0.004). EGFR reactivity in metastases appeared to have the strongest correlation with reactivity in the deep regions of colon adenocarcinoma. An increasing percentage of 2+ and 3+ or 3+ only reactivity in the deep region was found to have the strongest correlation with decreased survival (P = 0.0252).

CONCLUSIONS

EGFR reactivity of 2+ and 3+ may provide a framework for a scoring system. It may be important to evaluate EGFR reactivity in the deepest region of tumor invasion because this region appears to contain the largest percentage of 3+ reactive cells and appears to have the strongest correlation with survival length and EGFR reactivity in lymph node and liver metastases.

Polyamines in the human gut

Intracellular polyamine concentrations are maintained by endogenous synthesis and uptake of exogenous polyamines from the gastrointestinal lumen. Recently, much attention has been focused on the role of polyamines in tumour pathogenesis and the possible therapeutic value of reducing polyamine concentrations in tumour tissue. Unfortunately, polyamines also appear to be essential for the maintenance of normal gastrointestinal structure and function. The immediate analytical challenge is to make progress in laboratory methods for polyamine class analyses and assessment of polyamine metabolism. An obvious gastroenterological target is to make up for past neglect of the function of these important dietary components.

Epidermal growth factor receptor immunohistochemical reactivity in patients with American Joint Committee on Cancer Stage IV colon adenocarcinoma: implications for a standardized scoring system

BACKGROUND

An epidermal growth factor receptor (EGFR) immunohistochemical detection system currently is being developed. The current study attempts to address background EGFR reactivity issues before determining the optimum EGFR scoring system.

METHODS

Tissue sections from 102 patients with T3N1-2M1 colon adenocarcinoma were stained with a prototype EGFR detection system. The number of cases, location, percentage, and intensity of reactive cells (0+ [none] to 3+ [strong]) were scored and compared with the length of survival.

RESULTS

Approximately 75.5% of the adenocarcinoma cases had EGFR reactivity; 31.4% of the tumors had 3+ reactivity in 10-50% of the neoplastic cells and 3.9% had 3+ reactivity in > 50% of cells. Increased numbers of reactive cells per case predominantly resulted from increased 3+ reactivity. The mean percentage of 2+ (moderate) and 3+ reactive cells per case increased in the regions of deepest invasion. The mean percentage of 3+ reactivity per case was significantly greater in the deepest tumor region compared with the superficial region (16.9% vs. 7.9%; P = 0.004). EGFR reactivity in metastases appeared to have the strongest correlation with reactivity in the deep regions of colon adenocarcinoma. An increasing percentage of 2+ and 3+ or 3+ only reactivity in the deep region was found to have the strongest correlation with decreased survival (P = 0.0252).

CONCLUSIONS

EGFR reactivity of 2+ and 3+ may provide a framework for a scoring system. It may be important to evaluate EGFR reactivity in the deepest region of tumor invasion because this region appears to contain the largest percentage of 3+ reactive cells and appears to have the strongest correlation with survival length and EGFR reactivity in lymph node and liver metastases.

Expression of receptors for estrogen and progesterone in malignant colonic mucosa as a prognostic factor for patient survival

BACKGROUND AND OBJECTIVES

Estrogen receptors (ER) and progesterone receptors (PR) have been detected in both normal and malignant colonic mucosa, but the prognostic value of this observation is unknown. We aimed to define the prognostic significance of the presence of ER and PR in malignant cells from colorectal adenocarcinoma specimens.

METHODS

An immunohistochemical assay for ER and PR was performed on paraffinized sections from 65 colorectal adenocarcinoma specimens. Survival curves were analyzed to define the prognostic implications of ER and PR.

RESULTS

Twenty nine (45%) tumors tested receptor positive (32% for ER and 23% for PR). Tumors of advanced stage were more likely to express receptors than early stage tumors (56% vs. 32%; P = 0.01). Median survival of patients with neoplasms expressing PR was 30 months. For patients whose tumors did not express any receptors, median survival had not been reached at the time of follow-up (P = 0.04). Similarly, patients with tumors expressing both receptors had significantly reduced survival (median survival = 20 months; P = 0.003).

CONCLUSIONS

Expression of receptors for sex steroids correlates with advanced stage disease. Expression of PR by the tumor cells is associated with a shorter patient survival. The results suggest that sex steroids may play a role in carcinogenesis and tumor progression.

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.

Tamoxifen and risk of large bowel cancer in women with breast cancer

BACKGROUND

The increasingly consistent association between estrogen replacement therapy and colorectal cancer suggests that the anti-estrogen tamoxifen may also be associated with large bowel cancer incidence.

METHODS

Women with new diagnoses of breast cancer were identified from the Surveillance Epidemiology and End Results (SEER) Program, a set of geographically defined, population based cancer registries representing approximately ten percent of the U.S. population. Of 85,411 women with local or regional breast cancer diagnosed from 1983-90, 14,984 women were reported to have received hormonal therapy and 70,427 were not known to have received hormonal therapy. Subsequent cancer diagnoses were identified in this cohort beginning 6 months after initial breast cancer diagnosis until death, or December 31, 1994. Multivariate Cox proportional hazards models were used to estimate the risk of developing colorectal cancer and other second cancers according to hormonal therapy use.

RESULTS

Over the follow-up period 793 colorectal, 2,648 contralateral breast, 506 endometrial, 250 ovarian, 98 gastric, and 1,765 other cancers were identified in the study cohort. While overall there was no association between hormonal therapy use and colorectal cancer (relative risk (RR) 1.09, 95% confidence interval (CI) 0.88-1.35), in the period five or more years after diagnosis, risk was increased significantly by about 50% (95% CI 1.00-2.15). As expected, based upon clinical trials data, cancers of the contralateral breast were significantly decreased, and cancers of the uterine endometrium were significantly increased. No other meaningful associations were observed. When women were excluded for whom hormonal therapy might represent therapy other than tamoxifen (premenopausal women and those who received chemotherapy), this did not meaningfully alter these estimates.

CONCLUSIONS

The results of this large population based cohort study suggest that tamoxifen therapy may modestly increase risk of large bowel cancer in women, but only after 5 years following initiation of breast cancer therapy.

Separation of several free polyamines and their acetylated derivatives by ion-pair reversed-phase high performance liquid chromatography

Free polyamines and their acetylated derivatives, [putrescine (Put), spermine (Spm), spermidine (Spd), N1-acetylspermidine N1-AcSpd), N8-acetylspermidine N8-AcSpd)], were separated using ion-pair reversed-phase liquid chromatography after pre-column derivatization with dansyl chloride. Also 1,6-hexanediamine (1,6-Hda) and 1,7-diaminoheptane (1,7-Dah) which used as an internal standards were separated under the same chromatographic conditions. The reported method provided a good resolution between N1-AcSpd and N8 AcSpd (Rs = 0.86). This quality of resolution together with the very low detection limit obtained, (33.6, 8.33, 2.72, 2.67, 4.76, 4.27, and 2.27 fmoles/microliters for N1-AcSpd, N8-AcSpd, Put, 1,6-Hda, 1,7-Dah, Spm, and Spd, respectively), offer advantages to this method. Furthermore, a significant correlation coefficients were obtained as follows: 0.998 (N8-AcSpd), 0.996 N1-AcSpd), 0.997 (Put), 0.9995 (1,6-Hda), 0.9992 (1,7-Dah), 0.9996 (Spd), and 0.997 (Spm). The described method can be adapted for the separation of the free and acetylated polyamines in biological specimens.

LOCALIZAÇÃO DE LESÕES TUMORAIS INDUZIDAS PELA 1,2-DIMETILHIDRAZINA E SEU GRAU DE ATIPIA NO COLON DE RATOS

As diversas técnicas para o tratamento cirúrgico da Síndrome do Intestino Curto apresentam, ainda hoje, problemas de difícil resolução. De todas, as mais promissoras são o transplante de intestino delgado e o transplante de colo. Uma técnica intermediária que mostrou resultados controversos tanto clínicos como experimentais, é a interposição de segmentos de colo no trajeto do intestino delgado após extensas ressecções. Sua aplicação serve, todavia, como um meio de se estudar a adaptação do colo, inclusive visando os transplantes. Neste trabalho foi estudada a indução de tumores pela 1,2-dimetilhidrazina, sua localização e grau de atipia nos diferentes segmentos intestinais após ressecção de 80% do jejuno-íleo. Foram encontradas 24 lesões ao exame macroscópico após a décima sexta semana de pós-operatório. O número de lesões por animal variou de 0 a 9. Das 24 lesões encontradas, 20 estavam no colo (83,33%), sendo que 11 estavam localizadas no cólon proximal, 3 no cólon distal e 6 anorretais. No estudo histológico, a maioria das lesões era de grau III. Este trabalho mostrou que o método de indução de tumores pela 1,2-dimetilhidrazina é apropriado para o estudo de tumores intestinais em ratos.

Herbicide/pesticide effects on intestinal epithelial growth

The purpose of the present study was to examine the effects of some common herbicides and pesticides on the growth of normal intestinal and colonic epithelial cells. Preconfluent cultures of normal rat intestinal cells (IEC-6 cell line) and normal human colonic epithelial cells were treated with 0.05-50 microM doses of atrazine, diazinon, and endosulfan. After 3 days of treatment, the change in cell proliferation was quantified by cell counting or the MTT growth assay. Both intestinal and colonic epithelial cell cultures had increases in cell growth when treated with as little as 1.0 microM atrazine, diazinon, or endosulfan. The observed changes in both cultured intestinal and colonic cell growth rates were not due to the influence of the vehicle control dimethyl sulfoxide (DMSO). That is, the treatment of the cell cultures with concentrations of DMSO as high as 0.5% for 3 days resulted in no change in cell growth compared with untreated control cultures. A consistent observation with all three of the compounds was that the highest doses (50 microM) had the least "proliferative potential" in stimulating either IEC-6 cell or human colonic epithelial cell growth. Within the concentration range used, none of the herbicides or pesticides caused a decrease in cell proliferation below that of the untreated control cultures. Overall, treatment of IEC-6 cell cultures with atrazine, diazinon, or endosulfan produced a biphasic growth response, whereas the same treatment in the human colonic epithelial cell cultures produced a more sustained level of growth over the same period. This culture system may provide the basis for an in vitro model to further study the cellular and molecular basis of the effects of herbicides and pesticides on intestinal epithelial proliferation.

Molecular study of sex steroid receptor gene expression in human colon and in colorectal carcinomas

BACKGROUND

Sex steroid hormones influence function of the human gastrointestinal tract. Although the specific receptor proteins have been identified in surgical specimens of both intestinal mucosa and colorectal carcinomas, it is still unknown whether they are expressed in intestinal epithelial cells.

METHODS

Expression of androgen receptor (AR) protein and estrogen receptor (ER) protein was studied by Scatchard analysis and ELISA (for ER only) in surgical specimens of normal-appearing mucosa, colorectal carcinomas, isolated colonocytes, and human colorectal carcinoma cell lines. Northern analysis was applied to identify the appropriate mRNAs, followed by the sensitive technique of reverse transcription-polymerase-chain-reaction (RT-PCR).

RESULTS

AR protein was identified in all surgical specimens analyzed and ER protein in 10 out of 13 normal-appearing mucosa specimens and 4 out of 7 colorectal carcinomas. The receptor proteins were not found in isolated colonocytes or in the transformed cell lines. RT-PCR confirmed that none of the isolated normal colonocytes or transformed colorectal carcinoma-derived cells expressed these mRNAs. Intestinal smooth muscle cells and fibroblasts were found to express sex steroid receptor mRNAs.

CONCLUSIONS

Both receptors are present in human large intestine but are expressed in stromal cells and not in intestinal epithelial cells. We hypothesize that sex steroids may influence the function of colonocytes indirectly through stromal-epithelial interactions.

Successful eradicating treatment of Helicobacter pylori in patients with chronic gastritis: gastric levels of cytokines, epidermal growth factor and polyamines before and after therapy

In 10 patients with Helicobacter pylori (HP) positive chronic gastritis, gastric mucosal content of interleukin (IL)-1 beta, IL-8, Transforming Growth Factor (TGF)-beta 1, Epidermal Growth Factor (EGF) and Polyamines (putrescine, spermine and spermidine) was evaluated before and after eradicating treatment. Histologically, in all patients eradication of HP was accompanied by a marked reduction of the inflammatory infiltrate. At the same time, at the end of the therapeutical regimen, elevated levels of IL-1 beta, IL-8, TGF-beta 1, putrescine and spermidine/spermine ratio significantly dropped, while EGF mucosal content, significantly increased. Results are discussed in terms of the reciprocal role of inflammatory cytokines, growth factors and polyamines in the evolution of the HP-associated chronic gastritis.

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.

Prognostic value of cytosolic estrogen receptors in human colorectal carcinoma and surrounding mucosa. Preliminary results

Estrogen receptors have been found in normal and neoplastic gastrointestinal mucosa. The aim of our study was to verify whether the content of cytosolic estrogen receptor in normal and neoplastic tissue has a prognostic value in patients with colorectal adenocarcinoma. Eighty consecutive patients entered the study, and their follow-up was complete because none were lost to follow-up. Estrogen receptors were evaluated by an enzymatic immunoassay. Fifty-four percent of neoplastic samples and 84% of samples from surrounding mucosa showed an estrogen receptor content higher than 1.0 fmol/mg of cytosolic proteins (cut point for positive/negative hormone receptor status). Estrogen receptor levels were lower in neoplastic tissue than surrounding mucosa (1.2 +/- 1.05 fmol/mg protein vs 2.07 +/- 1.36 fmol/mg protein, respectively, t test P = 0.001). The survival of patients with estrogen receptor expression in uninvolved surrounding mucosa was longer than that of patients without estrogen receptor in the same type of mucosa (log rank test, P < 0.01). In the neoplastic tissue, receptor status had no prognostic value (log rank, P = 0.8). After taking into account the most important potential confounders by using the Cox proportional hazard model, the estrogen receptor status in normal mucosa samples maintained an independent prognostic value. These results support an association between the estrogen receptor status in normal mucosa and survival of patients with colorectal adenocarcinoma.

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.