Subsite-specific differences of estrogen receptor beta expression in the normal colonic epithelium: implications for carcinogenesis and colorectal cancer epidemiology

Differences between men and women with respect to colorectal cancer mortality despite screening colonoscopy

BACKGROUND AND AIMS

Women aged 55 to 59 years have a similar prevalence rate and number needed to screen for colorectal adenomas as men at a 10-year younger age. The aim of this study was to determine sex-specific differences in colorectal cancer mortality and estimate the association with adenomas at screening colonoscopy.

METHODS

This retrospective study analyzed 323,139 individuals who underwent colonoscopy within a national colorectal cancer screening program in Austria between January 2007 and December 2020.

RESULTS

Median patient age was 60 years (interquartile range, 54-67), and the sex distribution in all age groups was nearly identical. Men had significantly higher odds of having an adenoma or serrated polyp, low-risk polyp, high-risk polyp, or colorectal cancer detected at colonoscopy than women (odds ratio [OR] 1.83; 95% confidence interval [CI], 1.80-1.86; OR, 1.46; 95% CI, 1.44-1.49; OR, 1.74; 95% CI, 1.69-1.80; and OR, 1.87; 95% CI, 1.70-2.05, respectively). Strikingly, male sex, when compared with female sex, was associated with an almost 2-fold (hazard ratio, 1.67; 95% CI, 1.05-2.67) increased risk to die from colorectal cancer when an adenoma or serrated polyp was found at the screening colonoscopy and a 4-fold (hazard ratio, 4.14; 95% CI, 2.72-6.3) increased risk when a high-risk polyp was found at the screening colonoscopy. The cumulative incidence for death of colorectal cancer for 60-year-old individuals was 8.5-fold higher in men as compared with women. Markedly, this sex gap narrowed with increasing age, whereas the difference in deaths of other causes remained similar in all age groups.

CONCLUSIONS

Our findings strengthen the necessity of sex-specific screening recommendations. Importantly, further prospective studies should focus on sex differences in tumor biology to propose personalized surveillance guidelines.

Evaluating sex as a predictive marker for response to bevacizumab in metastatic colorectal carcinoma: Pooled analysis of 3,369 patients in the ARCAD database

BACKGROUND

Previous studies suggest a possible sex-specific response to bevacizumab in metastatic colorectal carcinoma (mCRC), showing a benefit in males, while the effect in females is less significant.

METHODS

Data from 3369 patients with mCRC enrolled on four first-line randomised trials testing chemotherapy with or without bevacizumab (2000-2007) were pooled. Association between sex and progression-free survival and overall survival (OS) was evaluated by stratified Cox regression model, adjusted for potential confounders. Predictive value was evaluated by interaction effect between sex and treatment. In a pre-planned secondary analysis, analyses were stratified using an age cut point of 60 years to evaluate the possible role of menopausal-related effects.

RESULTS

Bevacizumab was associated with an improved median OS in males and females, with a 2.3- and 0.6-months benefit, respectively. Stratified by age, bevacizumab resulted in improved OS in males at both age categories. In females at or above the age of 60 (n = 731), bevacizumab resulted in improved OS. However, in females below the age of 60 (n = 634), OS benefit did not reach statistical significance (adjusted hazard ratio = 0.94, 95% confidence interval 0.74-1.20).

CONCLUSIONS

Our results confirmed the OS benefit from the addition of bevacizumab to first-line chemotherapy in mCRC in both sexes. Among females, the benefit was less than 1 month. For females under the age of 60, there was no survival benefit. These findings could be used to relieve financial toxicity or be redistributed within healthcare systems for other health-related purposes.

Profiling estrogen, progesterone, and androgen receptors in colorectal cancer in relation to gender, menopausal status, clinical stage, and tumour sidedness

Background

Although estrogen (ERα/ERβ), progesterone (PGR), and androgen (AR) receptors are pathologically altered in colorectal cancer (CRC), their simultaneous expression within the same cohort of patients was not previously measured.

Methods

ERα/ERβ/PGR/AR proteins were measured in archived paired normal and malignant colon specimens (n =120 patients) by immunohistochemistry, and results were analyzed by gender, age (≤50 vs. ≥60 years), clinical stages (early-stage I/II vs. late-stage III/IV), and anatomical location (right; RSCs vs. left; LSCs). Effects of 17β-estradiol (E2), progesterone (P4), and testosterone alone or combined with the specific blockers of ERα (MPP dihydrochloride), ERβ (PHTPP), PGR (mifepristone), and AR (bicalutamide) on cell cycle and apoptosis were also measured in the SW480 male and HT29 female CRC cell lines.

Results

ERα and AR proteins increased, whilst ERβ and PGR declined markedly in malignant specimens. Moreover, male neoplastic tissues showed highest AR expression, whilst ERβ and PGR weakest alongside ERα strongest expression was seen in cancerous tissues from women aged ≥60 years. Late-stage neoplasms also revealed maximal alterations in the expression of sex steroid receptors. By tumor location, LSCs disclosed significant elevations in ERα with marked declines in PGR compared with RSCs, and ERα strongest alongside PGR weakest expression was detected in advanced LSCs from women aged ≥60 years. Late-stage LSCs from females aged ≥60 years also showed weakest ERβ and strongest AR expression. In contrast, male RSC and LSC tissues exhibited equal ERβ and AR expression in all clinical stages. ERα and AR proteins also correlated positively, whereas ERβ and PGR inversely, with tumor characteristics. Concomitantly, E2 and P4 monotherapies triggered cell cycle arrest and apoptosis in the SW480 and HT29 cells, and while pre-treatment with ERα-blocker enhanced the effects of E2, ERβ-blocker and PGR-blocker suppressed the E2 and P4 anti-cancer actions, respectively. In contrast, treatment with the AR-blocker induced apoptosis, whilst co-treatment with testosterone hindered the effects.

Conclusions

This study advocates that protein expression of sex steroid receptors in malignant tissues could represent prognostic markers, as well as hormonal therapy could provide an alternative strategy against CRC, and their efficacies could be dependent on gender, clinical stage, and tumor location.

Predictors of CRC Stage at Diagnosis among Male and Female Adults Participating in a Prospective Cohort Study: Findings from Alberta's Tomorrow Project

Colorectal cancer (CRC) is a leading cause of morbidity and mortality in Canada. CRC screening and other factors associated with early-stage disease can improve CRC treatment efficacy and survival. This study examined factors associated with CRC stage at diagnosis among male and female adults using data from a large prospective cohort study in Alberta, Canada. Baseline data were obtained from healthy adults aged 35–69 years participating in Alberta’s Tomorrow Project. Factors associated with CRC stage at diagnosis were evaluated using Partial Proportional Odds models. Analyses were stratified to examine sex-specific associations. A total of 267 participants (128 males and 139 females) developed CRC over the study period. Among participants, 43.0% of males and 43.2% of females were diagnosed with late-stage CRC. Social support, having children, and caffeine intake were predictors of CRC stage at diagnosis among males, while family history of CRC, pregnancy, hysterectomy, menopausal hormone therapy, lifetime number of Pap tests, and household physical activity were predictive of CRC stage at diagnosis among females. These findings highlight the importance of sex differences in susceptibility to advanced CRC diagnosis and can help inform targets for cancer prevention programs to effectively reduce advanced CRC and thus improve survival.

Sex Differences in the Incidence of Obesity-Related Gastrointestinal Cancer

Cancer is the second leading cause of death worldwide, with 9.6 million people estimated to have died of cancer in 2018. Excess body fat deposition is a risk factor for many types of cancer. Men and women exhibit differences in body fat distribution and energy homeostasis regulation. This systematic review aimed to understand why sex disparities in obesity are associated with sex differences in the incidence of gastrointestinal cancers. Cancers of the esophagus, liver, and colon are representative gastrointestinal cancers, and obesity is a convincing risk factor for their development. Numerous epidemiological studies have found sex differences in the incidence of esophageal, liver, and colorectal cancers. We suggest that these sexual disparities are partly explained by the availability of estrogens and other genetic factors regulating inflammation, cell growth, and apoptosis. Sex differences in gut microbiota composition may contribute to differences in the incidence and phenotype of colorectal cancer. To establish successful practices in personalized nutrition and medicine, one should be aware of the sex differences in the pathophysiology and associated mechanisms of cancer development.

DNA methylation in the upstream CpG island of the GPER locus and its relationship with GPER expression in colon cancer cell lines

The G-protein coupled estrogen receptor (GPER), a proposed tumor suppressor, relays short-term non-genomic responses in target cells and tissues. It frequently undergoes down-modulation in primary tumors of the breast, ovary, and endometrium. Liu and co-workers recently reported loss of GPER expression in colorectal cancer and attributed it to DNA methylation-dependent silencing. We hypothesized that GPER expression is inversely correlated with methylation in the upstream CpG island (upCpGi) in the GPER locus. Methylation in the upCpGi was analysed by bisulfite sequencing and correlated with GPER expression in a panel of colon cancer cell lines. Eight downstream CpGs of the upCpGi was differentially methylated across the cell lines. Methylation in this differentially methylated region (DMR) correlated inversely with GPER expression. Two cell lines, namely SW620 and COLO-320DM, were compared in terms of their viability in response to varying concentrations of G1, a GPER specific agonist. SW-620 cells, which had the least methylated DMR and the highest level of GPER expression, showed significant loss of viability with 1 µM G1. COLO-320DM, which had the most methylated DMR and the lowest level of GPER expression, did not show a significant response to 1 µM G1. At 5 µM G1, SW620 cells showed a greater reduction in viability than COLO-320DM cells. DNA methylation in the DMR is inversely correlated with GPER expression. DNA methylation-dependent silencing of GPER may be, at least in part, the underlying reason behind the loss of estrogen's oncoprotective effect via GPER in the colon.

Linking Obesity with Colorectal Cancer: Epidemiology and Mechanistic Insights

The incidence of obesity and colorectal cancer (CRC) has risen rapidly in recent decades. More than 650 million obese and 2 billion overweight individuals are currently living in the world. CRC is the third most common cancer. Obesity is regarded as one of the key environmental risk factors for the pathogenesis of CRC. In the present review, we mainly focus on the epidemiology of obesity and CRC in the world, the United States, and China. We also summarize the molecular mechanisms linking obesity to CRC in different aspects, including nutriology, adipokines and hormones, inflammation, gut microbiota, and bile acids. The unmet medical needs for obesity-related CRC are still remarkable. Understanding the molecular basis of these associations will help develop novel therapeutic targets and approaches for the treatment of obesity-related CRC.

Targeting estrogen receptors in colorectal cancer

Hormones have become a useful therapeutic aspect of clinical endocrinology but how to use them to optimize the health benefits and avoid adverse effects is a major challenge. Estrogen is an indispensable hormone for proper biological functioning but is also implicated with the pathology of both the reproductive and non-reproductive tissues. Abnormal estrogen receptor signaling may increase the risk of development of a variety of diseases including colorectal cancer (CRC). Estrogen receptor beta (ERβ) is the predominant subtype in the colonic epithelium and confers the anti-tumor effect through various mechanisms. Many investigators have embarked on the search for the biological mechanisms by which estrogen and estrogen-like compounds may influence the pathogenesis of CRC. This review explores the recent findings on the therapeutic role of ERβ in the colonic epithelium as a prospective candidate for targeted endocrine therapy in CRC.

Relationship between drugs affecting the renin-angiotensin system and colorectal cancer: The MCC-Spain study

The potential protective effect of renin-angiotensin system (RAS) inhibitors is a subject of increasing interest due to their possible role as chemopreventive agents against colorectal cancer (CRC). To evaluate this association, we conducted a case-control study with 2165 cases of colorectal cancer, diagnosed between 2007 and 2012, and 3912 population controls frequency matched (by age, sex and region) from the Spanish multicenter case-control study MCC-Spain. We found a significant protective effect of the angiotensin-converting enzyme Inhibitors (ACEIs) against CRC, limited to the under-65years group (OR=0.65 95%CI (0.48-0.89)) and to a lesser degree to men (OR=0.81 95%CI (0.66-0.99). In contrast, the angiotensin receptor blockers (ARBs) did not show a significant effect. Regarding the duration of use, a greater protection was observed in men as the length of consumption increases. In contrast, in the under-65 stratum, the strongest association was found in short-term treatments. Finally, by analyzing ACEIs effect by colon subsite, we found no differences, except for under 65years old, where the maximum protection was seen in the proximal intestine, descending in the distal and rectum (without statistical significance). In conclusion, our study shows a protective effect on CRC of the ACEis limited to males and people under 65years old, which increases in proximal colon in the latter. If confirmed, these results may suggest a novel approach to proximal CRC prevention, given the shortcomings of colonoscopy screening in this location.

Estrogen receptor β expression and colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Estrogen receptor β (ERβ) is a potential tumor-suppressor gene in colorectal cancer (CRC). This hypothesis is supported by clinical and laboratory observations.

AIM

In this meta-analysis, we looked at studies that investigated the relationship between ERβ protein expression and CRC, comparing the lesion with normal adjacent mucosa.

METHODS

English medical literature searches were performed for ERβ expression in patients with CRC, tumor tissue versus normal mucosa. Searches were performed up to 31 May 2015, using MEDLINE, PubMed, EMBASE, Scopus, and CENTRAL. Meta-analysis was carried out using Comprehensive Meta-analysis Software. Pooled odds ratios and 95% confidence intervals were calculated and ERβ expression was compared in individual studies using the fixed-effects model.

RESULTS

The odds ratio of ERβ expression was 0.216 (95% confidence interval 0.152-0.307, P<0.0001), lower in cancer tissue than normal mucosa. Funnel plot did not indicate a significant publication bias. There was no significant heterogeneity in the studies included: Q=5.897, d.f.(Q)=9, I=0.000, P=0.750.

CONCLUSION

In this meta-analysis, we confirm the observation of decreased ERβ expression in CRC. Our results support the hypothesis of ERβ being a tumor-suppressor gene in the large bowel, and the ERβ protein protects against carcinogenesis and development of CRC when activated by estrogen. Further studies are needed to examine the potential of selective/specific ligands to activate ERβ without the side effects found with estrogen and without activating ERα.

SUMMARY

In this meta-analysis, we looked at studies that investigated the relationship between CRC and ERβ expression in the tumor and normal mucosa of CRC patients. English medical literature searches were performed for studies comparing ERβ expression in the cancer and normal colonic mucosa in patients with CRC. Meta-analysis was carried out, pooled odds ratios were calculated, and ERβ expression was compared in individual studies.

Isoflavone and Soyfood Intake and Colorectal Cancer Risk: A Case-Control Study in Korea

We aimed to assess the relationship between dietary soyfood and isoflavone intake and colorectal cancer risk in a case-control study. A total of 901 colorectal cancer cases and 2669 controls were recruited at the National Cancer Center, Korea. A semi-quantitative food frequency questionnaire was used to assess the usual dietary habits, and the isoflavone intake level was estimated from five soyfood items. A high intake of total soy products, legumes, and sprouts was associated with a reduced risk for colorectal cancer in men and women, although the middle quartiles of intake of total soy products were associated with an elevated risk. In contrast, a high intake of fermented soy paste was associated with an elevated risk for colorectal cancer in men. The groups with the highest intake quartiles of isoflavones showed a decreased risk for colorectal cancer compared to their counterparts with the lowest intake quartiles in men (odds ratio (OR): 0.67, 95% confidence interval (CI): 0.51–0.89) and women (OR: 0.65, 95% CI: 0.43–0.99). The reduced risk for the highest intake groups persisted for distal colon cancer in men and rectal cancer in women. The association between soyfood intake and colorectal cancer risk was more prominent among post-menopausal women than pre-menopausal women. In conclusion, a high intake of total soy products or dietary isoflavones was associated with a reduced risk for overall colorectal cancer, and the association may be more relevant to distal colon or rectal cancers.

Eph receptor and ephrin function in breast, gut, and skin epithelia

Epithelial cells are tightly coupled together through specialized intercellular junctions, including adherens junctions, desmosomes, tight junctions, and gap junctions. A growing body of evidence suggests epithelial cells also directly exchange information at cell-cell contacts via the Eph family of receptor tyrosine kinases and their membrane-associated ephrin ligands. Ligand-dependent and -independent signaling via Eph receptors as well as reverse signaling through ephrins impact epithelial tissue homeostasis by organizing stem cell compartments and regulating cell proliferation, migration, adhesion, differentiation, and survival. This review focuses on breast, gut, and skin epithelia as representative examples for how Eph receptors and ephrins modulate diverse epithelial cell responses in a context-dependent manner. Abnormal Eph receptor and ephrin signaling is implicated in a variety of epithelial diseases raising the intriguing possibility that this cell-cell communication pathway can be therapeutically harnessed to normalize epithelial function in pathological settings like cancer or chronic inflammation.

Distribution characteristics of 3,369 chinese colorectal cancer patients for gender, age, location and tumor size during colonoscopy

BACKGROUND

Studies have shown the existence of gender- and age-related differences in the incidence and anatomic distribution of colorectal cancers. The purposes of this study were to analyze the distribution characteristics of colorectal cancer patients regarding gender, age, location and tumor size in the course of colonoscopy.

MATERIALS AND METHODS

All colorectal cancer patients who underwent colonoscopy in the First Affiliated Hospital of Guangxi Medical University from 2003 to 2012 were included in our retrospective study. Demographic information (age and gender) and colonoscopy report information (tumor size and location) were collected and analyzed. To compare the gender differences in tumor location and tumor size, as well as the size differences in tumor location, the chi-square test was used.

RESULTS

A total of 3, 369 colorectal cancer patients (2, 007 men vs 1, 362 women) were included in our study. Statistical analysis showed there was no gender difference in the anatomic distribution of the tumors (p>0.05). However, there was a gender difference in tumor size (p>0.05). In addition, our study found there was a significant difference in tumor size between rectal and colon tumors (p>0.001).

CONCLUSIONS

There was no gender difference in the anatomic distribution of colorectal tumors. In addition, tumors observed in men were larger than in women.

Clinical significance of DNA methylation mRNA levels of TET family members in colorectal cancer

Purpose

Ten eleven translocation (TET) enzyme activity is essential for active DNA demethylation in biological processes, and their altered expression has been observed in various malignancies. Therefore, we investigated DNA methylation and mRNA levels of all TETs in colorectal cancer (CRC) patients.

Methods

TET mRNA levels were evaluated using quantitative RT-PCR in primary cancerous and histopathologically unchanged colorectal tissues from patients who underwent radical surgical colon resection (n = 113). DNA methylation levels of the TET CpG island were assessed using bisulfite DNA sequencing and high-resolution melting analysis.

Results

We found reduced transcript levels of TET1, TET2 and TET3 in cancerous tissue compared with their histopathologically unchanged counterparts (p = 0.000011; p = 0.000001; p = 0.00031, respectively). Importantly, multivariate Cox regression analysis revealed favorable overall survival (OS) and disease-free survival (DFS) outcomes for patients with high TET2 mRNA levels in histopathologically unchanged tissue (HR^OS = 0.091, 95 % CI 0.011–0.77, p = 0.028; HR^DFS = 0.21, 95 % CI 0.04–1.06, p = 0.059). Moreover, we found no DNA methylation in the TET2 and TET3 promoter regions in cancerous and histopathologically unchanged tissue. In contrast, we reported TET1 DNA hypermethylation in a small fraction of patients (n = 12/113).

Conclusion

To best of our knowledge, our study is the first to investigate TET mRNA levels in a cohort of CRC patients and correlate them with patients’ prognosis. Present study provides the evidence that TET2 mRNA expression may be an independent prognostic factor for disease recurrence and outcome. Additionally, our findings initially indicate the importance of DNA methylation in regulating TET1 expression.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-014-1901-2) contains supplementary material, which is available to authorized users.

Repeat polymorphisms in ESR2 and AR and colorectal cancer risk and prognosis: results from a German population-based case-control study

Background

Evidence has accumulated which suggests that sex steroids influence colorectal cancer development and progression. We therefore assessed the association of repeat polymorphisms in the estrogen receptor β gene (ESR2) and the androgen receptor gene (AR) with colorectal cancer risk and prognosis.

Methods

The ESR2 CA and AR CAG repeat polymorphisms were genotyped in 1798 cases (746 female, 1052 male) and 1810 controls (732 female, 1078 male), matched for sex, age and county of residence. Colorectal cancer risk associations overall and specific for gender were evaluated using multivariate logistic regression models adjusted for sex, county of residence and age. Associations with overall and disease-specific survival were evaluated using Cox proportional hazard models adjusted for established prognostic factors (diagnosis of other cancer after colorectal cancer diagnosis, detection by screening, treatment with adjuvant chemotherapy, tumour extent, nodal status, distant metastasis, body mass index, age at diagnosis and year of diagnosis) and stratified for grade of differentiation. Heterogeneity in gender specific associations was assessed by comparing models with and without a multiplicative interaction term by means of a likelihood ratio test.

Results

The average number of ESR2 CA repeats was associated with a small 5% increase in colorectal cancer risk (OR = 1.05, 95% CI 1.01-1.10) without significant heterogeneity according to gender or tumoural ESR2 expression. We found no indication for an association between the AR CAG repeat polymorphisms and risk of colorectal cancer. The ESR2 CA and AR CAG repeat polymorphisms were not associated with overall survival or disease specific survival after colorectal cancer diagnosis.

Conclusions

Higher numbers of ESR2 CA repeats are potentially associated with a small increase in colorectal cancer risk. Our study does not support an association between colorectal cancer prognosis and the investigated repeat polymorphisms.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-817) contains supplementary material, which is available to authorized users.

Proximal shift of colorectal cancer along with aging

INTRODUCTION

Although several reports have documented the increased incidence of right-sided colorectal cancer (CRC) in the elderly, especially in women, the gender-specific, age-related changes in the characteristics of CRCs, especially related to the cancer localization, have not been fully investigated. This study evaluated the age-related changes in the clinicopathologic features of CRCs, according to the gender.

MATERIALS AND METHODS

A total of 1059 consecutive patients with CRCs who were admitted to the authors' surgical department between February 2005 and June 2012 were retrospectively reviewed. The patients were divided into male (n = 632) and female (n = 427) groups and then according to the age group, and the correlation between the age group and the other clinicopathologic features was analyzed by univariate and multivariate analysis.

RESULTS

The number of concomitant adenomas found was significantly increased along with increasing age in men, and the presence of concomitant adenoma was the only independent age-related factor of male CRC in the multivariate analysis (P = .0044). In contrast, in women, the location of the CRC progressively shifted to the right side (proximal colon) with increasing age, and the presence of right-sided CRC was the only independent factor of female CRC in the multivariate analysis (P < .0001).

CONCLUSION

There was a significant gender-specific difference in the age-related changes in the characteristics of CRC. Increasing the number of concomitant adenomas and the shift of CRC localization to the proximal colon were the gender-specific characteristics of male and female CRC, respectively.

Associations between circulating 1,25(OH)₂D concentration and odds of metachronous colorectal adenoma

Cellular-level studies demonstrate that the availability of the secosteroid hormone 1α,25-dihydroxyvitamin D [1,25(OH)2D] to colon cells promotes anti-carcinogenic activities. Although epidemiological data are relatively sparse, suggestive inverse trends have been reported between circulating 1,25(OH)2D concentration and colorectal neoplasia. We therefore sought to evaluate the relationship between circulating 1,25(OH)2D concentrations and odds for metachronous colorectal adenomas among 1,151 participants from a randomized trial of ursodeoxycholic acid for colorectal adenoma prevention. No relationship between 1,25(OH)2D and overall odds for metachronous lesions was observed, with ORs (95% CIs) of 0.80 (0.60-1.07) and 0.81 (0.60-1.10) for participants in the second and third tertiles, respectively, compared with those in the lowest (p-trend = 0.17). However, a statistically significant inverse association was observed between circulating 1,25(OH)2D concentration and odds of proximal metachronous adenoma, with an OR (95% CI) of 0.71 (0.52-0.98) for individuals in the highest tertile of 1,25(OH)2D compared with those in the lowest (p-trend = 0.04). While there was no relationship overall between 1,25(OH)2D and metachronous distal lesions, there was a significantly reduced odds for women, but not men, in the highest 1,25(OH)2D tertile compared with the lowest (OR 0.53; 95% CI 0.27-1.03; p-trend = 0.05; p-interaction = 0.08). The observed differences in associations with proximal and distal adenomas could indicate that delivery and activity of vitamin D metabolites in different anatomic sites in the colorectum varies, particularly by gender. These results identify novel associations between 1,25(OH)2D and metachronous proximal and distal colorectal adenoma, and suggest that future studies are needed to ascertain potential mechanistic differences in 1,25(OH)2D action in the colorectum.

Molecular pathways: Estrogen pathway in colorectal cancer

Worldwide, colorectal cancer has a higher incidence rate in men than in women, suggesting a protective role for sex hormones in the development of the disease. Preclinical data support a role for estrogen and its receptors in the initiation and progression of colorectal cancer and establishes that protective effects of estrogen are exerted through ERβ. Hormone replacement therapy (HRT) in postmenopausal women as well as consumption of soy reduces the incidence of colorectal cancer. In the Women's Health Initiative trial, use of HRT in postmenopausal women reduced the risk of colon cancer by 56% [95% confidence interval (CI), 0.38-0.81; P = 0.003]. A recent meta-analysis showed that in women, consumption of soy reduced the risk of colon cancer by 21% (95% CI, 0.03-0.35; P = 0.026). In this review, using the preclinical data, we translate the findings in the clinical trials and observational studies to define the role of estrogen in the prevention of colorectal cancer. We hypothesize that sometime during the tumorigenesis process ERβ expression in colonocytes is lost and the estrogen ligand, HRT, or soy products, exerts its effects through preventing this loss. Thus, in the adenoma-to-carcinoma continuum, timing of HRT is a significant determinant of the observed benefit from this intervention. We further argue that the protective effects of estrogen are limited to certain molecular subtypes. Successful development of estrogen modulators for prevention of colorectal cancer depends on identification of susceptible colorectal cancer population(s). Thus, research to better understand the estrogen pathway is fundamental for clinical delivery of these agents.

Oestrogen and colorectal cancer: mechanisms and controversies

AIM

The role of oestrogen metabolism and action in colorectal cancer (CRC) is controversial. An extensive review of the current literature, encompassing epidemiological evidence, systemic and peripheral oestrogen concentrations, 17β-hydroxysteroid dehydrogenase (17β-HSD) and aromatase in CRC, steroid sulphatase (STS)/oestrone sulphotransferase (EST) and in vitro and in vivo genomic effects was therefore undertaken.

METHODS

A literature search (key words: colorectal cancer, oestrogen, oestrogen receptor, 17β-HSD, STS, organic anion transporter) was performed using Embase, Medline, and Pubmed and papers were evaluated on scientific relevance on an individual basis.

RESULTS

Epidemiological data highlights that premenopausal women, or postmenopausal women taking hormone replacement therapy, are significantly less likely than males to develop CRC. This implies that oestrogen signalling is most likely involved in CRC physiology and aetiology. Little is known about oestrogen metabolism in the colon. However, the expression of 17β-HSD, STS, and EST, enzymes involved in oestrogen metabolism, have shown prognostic significance. Evidence also suggests that protective effects are modulated through oestrogen receptor beta, although which metabolite of oestrogen, oestradiol (E2) or oestrone (E1), is more active remains undefined. To complicate matters, the changes in the peripheral ratios of these enzymes, oestrogens and receptors most likely influences CRC progression.

CONCLUSION

Epidemiological evidence, now supported by in vitro and in vivo studies, strongly associates oestrogen action and metabolism with CRC. Initially protective against CRC, once developed, results suggests that oestrogens increase proliferation. Consequently, hormone-ablation therapy, already successful against breast and prostate cancer, may be effective against CRC.

Trends in colorectal incidence by anatomic subsite from 1985 to 2005: a population-based study

BACKGROUND

Conflicting results on the shift of right-left ratio in colon cancer incidence have been reported. We examine incidence trends by subsite in a population-based study.

MATERIALS AND METHODS

Colorectal cancer cases diagnosed in the 1985-2005 period were identified through the Tuscany Cancer Registry. Colon subsite was defined as proximal and distal; gender, age at diagnosis, histology, and stage were analyzed. Average annual incidence and age-specific rates according to subsite were calculated.

RESULTS

A total of 21,160 colorectal cancer cases were extracted; in 18,311 cases, the subsite was identified: 6,916 rectal, 5,239 proximal, and 6,156 distal. A larger proportion of distal colon cancers presented as early stage when compared with proximal. Incidence of rectal and distal colon cancer remained stable, while proximal colon cancer incidence increased.

CONCLUSIONS

Proximal colon cancer incidence rate increased through the period. Temporal variations in the incidence rate by subsite could suggest different carcinogenic pathways of right- and left-sided colon cancer.

Expression of oestrogen receptor β and prognosis of colorectal cancer

BACKGROUND

Previous studies suggest that sex steroids influence colorectal cancer (CRC) carcinogenesis. The oestrogen receptor β (ERβ) is the predominantly expressed ER in the colon and loss of ERβ in CRC has been associated with advanced cancer stages.

METHODS

Information on vital status by the end of 2009 was obtained for 1262 CRC patients recruited between 2003 and 2007. The ERβ expression was immunohistochemically measured and associations of ERβ scores with overall survival (OS), disease-specific survival (DSS) and disease-free survival (DFS) were evaluated using Cox proportional hazard models adjusted for prognostic factors, such as tumour stage and second primary tumours.

RESULTS

Of the 1101 tumour samples with successful measurement, 535 were ERβ negative (48.6%), 381 (34.6%) showed moderate and 185 (16.8%) showed high ERβ expression. Compared with high ERβ expression, lack of ERβ was associated with higher cancer stages as well as greater tumour extent. In multivariate analyses, ERβ negativity was associated with an increased hazard ratio for death (HR=1.61, 95% CI 1.09-2.40, P=0.02), death attributed to CRC (HR=1.54, 95% CI 0.99-2.39, P=0.06) as well as a poorer DFS (DFS HR=1.64, 95% CI 1.23-3.36, P=0.04). The associations were stronger in stage I-III patients (OS HR=2.20, 95% CI 1.28-4.06, P=0.007, DSS HR=2.38, 95% CI 1.20-5.39, P=0.02, respectively).

CONCLUSIONS

Lack of ERβ expression is associated with advanced cancer stages and independently associated with poor survival.

Estrogen receptors and human disease: an update

A myriad of physiological processes in mammals are influenced by estrogens and the estrogen receptors (ERs), ERα and ERβ. As we reviewed previously, given the widespread role for estrogen in normal human physiology, it is not surprising that estrogen is implicated in the development or progression of a number of diseases. In this review, we are giving a 5-year update of the literature regarding the influence of estrogens on a number of human cancers (breast, ovarian, colorectal, prostate, and endometrial), endometriosis, fibroids, and cardiovascular disease. A large number of sophisticated experimental studies have provided insights into human disease, but for this review, the literature citations were limited to articles published after our previous review (Deroo and Korach in J Clin Invest 116(3):561-570, 2006) and will focus in most cases on human data and clinical trials. We will describe the influence in which estrogen's action, through one of or both of the ERs, mediates the aforementioned human disease states.

Dietary, endocrine, and metabolic factors in the development of colorectal cancer

INTRODUCTION

Colorectal cancer is the third cause of death in industrialized countries. Genetic susceptibility and diet are determinant of cancer risk and tumor behavior. Variation in cancer incidence among and within populations with similar dietary patterns suggests that an individual response may reflect interactions with genetic factors, which may modify gene, protein, and metabolite expression patterns. Nutrigenomics, defined as the interaction between nutrition and an individual genome, will likely provide important clues about responders and non-responders to nutritional intervention.

DISCUSSION

Epidemiological and experimental studies suggest a protective role of some normal components of daily diet (fish oil, milk, and vegetables), estrogens, and phytoestrogens in colorectal cancer. The effect of estrogen seems to be mediated by their binding to estrogen receptor beta (ER-β), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-β in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-β agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen agonists in mammals. They are characterized by a higher binding affinity to ER-β as compared to estrogen receptor alpha (ER-α), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardiovascular accidents, higher incidence of endometrial and breast cancer) and makes these substances potential candidates for colorectal cancer prevention.

Estrogen-dependent regulation of sodium/hydrogen exchanger-3 (NHE3) expression via estrogen receptor β in proximal colon of pregnant mice

Although constipation is very common during pregnancy, the exact mechanism is unknown. We hypothesized that the involvement of estrogen receptor (ER) in the regulation of electrolyte transporter in the colon leads to constipation. In this study, the intestines of normal female ICR mouse and pregnant mice were examined for the expression of ERα and ERβ by immunohistochemistry and in situ hybridization. ERβ, but not ERα, was expressed in surface epithelial cells of the proximal, but not distal, colon on pregnancy days 10, 15, and 18, but not day 5, and the number of ERβ-positive cells increased significantly during pregnancy. Expression of NHE3, the gene that harbors estrogen response element, examined by immunohistochemistry and western blotting, was localized in the surface epithelial cells of the proximal colon and increased in parallel with ERβ expression. In ovariectomized mice, NHE3 expression was only marginal and was up-regulated after treatment with 17β-estradiol (E(2)), but not E(2) + ICI 182,780 (estrogen receptor antagonist). Moreover, knock-down of ERβ expression by electroporetically transfected siRNA resulted in a significant reduction of NHE3 expression. These results indicate that ERβ regulates the expression of NHE3 in the proximal colon of pregnant mice through estrogen action, suggesting the involvement of increased sodium absorption by up-regulated NHE3 in constipation during pregnancy.

Decreased expression of 17β-hydroxysteroid dehydrogenase type 1 is associated with DNA hypermethylation in colorectal cancer located in the proximal colon

BACKGROUND

The importance of 17β-estradiol (E2) in the prevention of large bowel tumorigenesis has been shown in many epidemiological studies. Extragonadal E2 may form by the aromatase pathway from androstenedione or the sulfatase pathway from estrone (E1) sulfate followed by E1 reduction to E2 by 17-β-hydroxysteroid dehydrogenase (HSD17B1), so HSD17B1 gene expression may play an important role in the production of E2 in peripheral tissue, including the colon.

METHODS

HSD17B1 expression was analyzed in colorectal cancer cell lines (HT29, SW707) and primary colonic adenocarcinoma tissues collected from fifty two patients who underwent radical colon surgical resection. Histopathologically unchanged colonic mucosa located at least 10-20 cm away from the cancerous lesions was obtained from the same patients. Expression level of HSD17B1 using quantitative PCR and western blot were evaluated. DNA methylation level in the 5' flanking region of HSD17B1 CpG rich region was assessed using bisulfite DNA sequencing and HRM analysis. The influence of DNA methylation on HSD17B1 expression was further evaluated by ChIP analysis in HT29 and SW707 cell lines. The conversion of estrone (E1) in to E2 was determined by electrochemiluminescence method.

RESULTS

We found a significant decrease in HSD17B1 transcript (p = 0.0016) and protein (p = 0.0028) levels in colorectal cancer (CRC) from the proximal but not distal colon and rectum. This reduced HSD17B1 expression was associated with significantly increased DNA methylation (p = 0.003) in the CpG rich region located in the 5' flanking sequence of the HSD17B1 gene in CRC in the proximal but not distal colon and rectum. We also showed that 5-dAzaC induced demethylation of the 5' flanking region of HSD17B1, leading to increased occupation of the promoter by Polymerase II, and increased transcript and protein levels in HT29 and SW707 CRC cells, which contributed to the increase in E2 formation.

CONCLUSIONS

Our results showed that reduced HSD17B1 expression can be associated with DNA methylation in the 5' flanking region of HSD17B1 in CRC from the proximal colon.