Alteration of gene expression in macroscopically normal colonic mucosa from individuals with a family history of sporadic colon cancer

A Four-Gene Panel in Rectal Swab Samples as a Biomarker for Colorectal Cancer Screening

BACKGROUND

The dysregulation of gene expression is one of the key molecular features of colorectal cancer (CRC) development. This study aimed to investigate whether such dysregulation is reflected in rectal swab specimens of CRC patients and to evaluate its potential as a non-invasive approach for screening.

METHODS

We compared the expression level of 14 CRC-associated genes in tumor and adjacent non-tumor tissue of CRC patients and examined the correlation of their levels in tissue with paired rectal swab specimens. The level of these 14 genes in rectal swab specimens was compared among patients with CRC or polyp and control subjects, and the diagnostic potential of each dysregulated gene and the gene panel were evaluated.

RESULTS

The expression of CXCR2, SAA, COX1, PPARδ, PPARγ, Groγ, IL8, p21, c-myc, CD44 and CSF1 was significantly higher in CRC, and there was a significant correlation in the levels of most of them between the CRC and rectal swab specimens. In the training study, we showed that CD44, IL8, CXCR2 and c-myc levels were significantly higher in the rectal swab specimens of the CRC patients. Such result was confirmed in the validation study. A panel of these four genes was developed, and ROC analysis showed that this four-gene panel could identify CRC patients with an AUC value of 0.83 and identify overall polyp and precancerous adenoma patients with AUC values of 0.6522 and 0.7322, respectively. Finally, the predictive study showed that the four-gene panel demonstrated sensitivities of 63.6%, 76.9% and 88.9% in identifying overall polyp, precancerous adenoma and CRC patients, respectively, whereas the specificity for normal subjects was 72.2%.

CONCLUSION

The expression of CRC-associated genes in rectal swab specimens reflects the dysregulation status in colorectal tissue, and the four-gene panel is a potential non-invasive biomarker for early precancerous adenoma and CRC screening.

Differential profile of protumor immunological factors between the tumor site and the tumor-free site - predictive potential of IL-8 and COX2 for colorectal cancer and metastasis

To study the role of host immune surveillance in the initiation and progression of colorectal cancer (CRC), a set of protumor immunological factors was determined by quantitative real-time PCR (q-PCR) between the primary tumor and the adjacent tumor-free site tissues in 63 patients with colorectal neoplasms. Results showed that expression levels of interleukin (IL)-1β, IL-6, IL-8, IL-17A, IL-23, and cyclooxygenase 2 (COX2) mRNAs, except transforming growth factor beta (TGFβ), in adenoma tissues were significantly higher than that in relative adjacent tissues. Difference of immunological factor levels between adenoma and adjacent tissues (Δ values) was in an order of ΔIL-8 > ΔIL-6 > ΔIL-17A > ΔIL-1β > ΔCOX2 > ΔIL-23; Analysis showed that the value of ΔCOX2 correlated to the grade of dysplastic degree in patients with adenoma. Notably, levels of all these immunological factors in CRC tissues were continuously increased, the order of values of Δ immunological factors was ΔIL-8 > ΔCOX2 > ΔIL-6 > ΔIL-1β > ΔIL-17A > ΔIL-23 > ΔTGFβ. Further analysis revealed that increased value of Δ IL-1β was associated with advanced TNM stage, a higher value of Δ COX2 tended to predicate a deeper degree of tumor invasion; and higher values of Δ IL-1β, IL-6 and COX2 closely correlated to lymph node metastasis in patients with CRC. In addition, the ratio of ΔIL-8/ΔTGFβ was most obvious changed factor and associated with node metastasis in patients with CRC. Therefore, we concluded that the difference of protumor immunological factor levels between the primary tumor site and tumor-free site along the adenoma-carcinoma sequence reflects the change of protumor/antitumor force balance, which is associated with CRC initiation and invasion.

The two sides of Hippo pathway in cancer

The Hippo signaling pathway was originally characterized by genetic studies in Drosophila to regulate tissue growth and organ size, and the core components of this pathway are highly conserved in mammals. Studies over the past two decades have revealed critical physiological and pathological functions of the Hippo tumor-suppressor pathway, which is tightly regulated by a broad range of intracellular and extracellular signals. These properties enable the Hippo pathway to serve as an important controller in organismal development and adult tissue homeostasis. Dysregulation of the Hippo signaling has been observed in many cancer types, suggesting the possibility of cancer treatment by targeting the Hippo pathway. The general consensus is that Hippo has tumor suppressor function. However, growing evidence also suggests that the function of the Hippo pathway in malignancy is cancer context dependent as recent studies indicating tumor promoting function of LATS. This article surveys the Hippo pathway signaling mechanisms and then reviews both the tumor suppressing and promoting function of this pathway. A comprehensive understanding of the dual roles of the Hippo pathway in cancer will benefit future therapeutic targeting of the Hippo pathway for cancer treatment.

Field carcinogenesis for risk stratification of colorectal cancer

Colorectal cancer (CRC) is characterized by genetic-environmental interplay leading to diffuse changes in the entire colonic mucosa (field carcinogenesis or field of injury) and to a pro-neoplastic genetic/epigenetic/physiological milieu. The clinical consequences are increased risk of synchronous and metachronous neoplasia. Factors such as genetics, race, ethnicity, age, and socioeconomic status are thought to influence neoplasia development. Here, we explore the potential improvement to CRC screening through exploiting field carcinogenesis, with particular focus on racial disparities and chemoprevention strategies. Also, we discuss future directions for field carcinogenesis/risk stratification using molecular and novel biophotonic techniques for personalized CRC screening.

Elevated proinflammatory cytokine IL-17A in the adjacent tissues along the adenoma-carcinoma sequence

Considerable evidence has suggested that chronic inflammation is a causative factor in the development of human colorectal cancer (CRC). Interleukin (IL)-17A produced mainly by Th17 cells is a novel proinflammatory cytokine and increased IL-17A is associated with colorectal neoplastic transformation. In this study, we have evaluated the expression of IL-17A in the adjacent tissues along the colorectal adenoma-carcinoma sequence. The expression of IL-17A in the adjacent tissues of colorectal adenoma (adenoma-adjacent, n = 32) and sporadic CRC (CRC-adjacent, n = 45) was examined. In addition, the expression pattern of Th17 cell differentiation stimulators (IL-1β, IL-6 and IL-23A) in the adjacent tissues were also examined. The results showed that the expression level of IL-17A mRNA was non-statistically increased (4-fold higher) in the adenoma-adjacent tissues and it became significantly increased (9-fold higher) in the CRC-adjacent tissues as compared with the control. The expression level of IL-17A in the CRC-adjacent tissues was not associated with CRC clinicopathological parameters and overall survival. Immunohistochemistry confirmed an increased density of intraepithelial IL-17A expressing cells in the CRC-adjacent tissues. The Th17 cell differentiation simulators IL-1β and IL-6 were also shown in an increase trend from the adenoma-adjacent to CRC-adjacent tissues. These results provide evidence that IL-17A/Th17 response is enhanced in the adjacent tissues during the colorectal neoplastic transformation.

[The effects of family history of colorectal cancer on the development of colorectal adenoma]

BACKGROUND/AIMS

Early detection of polyp is important for the prevention of colorectal cancer (CRC). There have been few studies to investigate the relationship between colorectal adenoma and family history of CRC (FHCRC) in Korea. The aim of this study was to identify the relationship between colorectal adenoma and FHCRC.

METHODS

Between March 2009 and September 2010, 225 patients with adenomatous polyps were included. Their medical records with clinical history and size, numbers, histology of polyps were reviewed. Immunohistochemical staining using Bcl-2, Bax, p-AKT, NF-κB, and β-catenin antibodies were performed. We compared the histology of adenoma and expression of immunohistochemical staining according to the existence of FHCRC.

RESULTS

The incidence of colorectal adenoma increased in case of FHCRC (p=0.029). In patients with FHCRC, the mean age of patients was 49 years old and younger than patients without FHCRC. In addition in patients with FHCRC, the incidence of advanced adenoma was significantly higher than in patients without FHCRC (p=0.001). The expression of Bax was significantly lower in patients with FHCRC than without FHCRC (p=0.046).

CONCLUSIONS

There was a tendency for polyp to develop in their younger ages and to be more advanced adenomas in patients with FHCRC. The low expression of Bax, tumor suppressor gene, might be associated with the development of polyps in patient with FHCRC. Therefore, patients with FHCRC may be better to start screening colonoscopy earlier than patient without FHCRC.

β-Catenin and peroxisome proliferator-activated receptor-δ coordinate dynamic chromatin loops for the transcription of vascular endothelial growth factor A gene in colon cancer cells

Vascular endothelial growth factor A (VEGFA) mRNA is regulated by β-catenin and peroxisome proliferator activated receptor δ (PPAR-δ) activation in colon cancer cells, but the detailed mechanism remains to be elucidated. As chromatin loops are generally hubs for transcription factors, we tested here whether β-catenin could modulate chromatin looping near the VEGFA gene and play any important role for PPAR-δ activated VEGFA transcription. First, we identified the far upstream site as an important site for VEGFA transcription by luciferase assay and chromatin immunoprecipitation in colorectal carcinoma HCT116 cells. Chromatin conformation capture analysis also revealed the chromatin loops formed by the β-catenin bindings on these sites near the VEGFA gene. Dynamic association and dissociation of β-catenin/TCF-4/PPAR-δ on the far upstream site and β-catenin/NF-κB p65 on the downstream site were also detected depending on PPAR-δ activation. Interestingly, β-catenin-mediated chromatin loops were relieved by PPAR-δ activation, suggesting a regulatory role of β-catenin for VEGFA transcription. Based on these data, we propose a model for PPAR-δ-activated VEGFA transcription that relies on β-catenin-mediated chromatin looping as a prerequisite for the activation. Our findings could extend to other β-catenin regulated target genes and could provide a general mechanism and novel paradigm for β-catenin-mediated oncogenesis.

Allelic transcripts dosage effect in morphologically normal ovarian cells from heterozygous carriers of a BRCA1/2 French Canadian founder mutation

We hypothesized that the transcriptome of primary cultures of morphologically normal ovarian surface epithelial cells could be altered by the presence of a heterozygous BRCA1 or BRCA2 mutation. We aimed to discover early events associated with ovarian carcinogenesis, which could represent putative targets for preventive strategies of this silent killer tumor. We identified the first molecular signature associated with French Canadian BRCA1 or BRCA2 founder mutations in morphologically normal ovarian epithelial cells. We discovered that wild-type and mutated BRCA2 allelic transcripts were expressed not only in morphologically normal but also in tumor cells from BRCA2-8765delAG carriers. Further analysis of morphologically normal ovarian and tumor cells from BRCA1-4446C>T carriers lead to the same observation. Our data support the idea that one single hit in BRCA1 or BRCA2 is sufficient to alter the transcriptome of phenotypically normal ovarian epithelial cells. The highest level of BRCA2-mutated allele transcript expression was measured in cells originating from the most aggressive ovarian tumor. The penetrance of the mutation and the aggressiveness of the related tumor could depend on a dosage effect of the mutated allele transcript.

The role of peroxisome proliferator-activated receptors in carcinogenesis and chemoprevention

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that are involved in regulating glucose and lipid homeostasis, inflammation, proliferation and differentiation. Although all of these functions might contribute to the influence of PPARs in carcinogenesis, there is a distinct need for a review of the literature and additional experimentation to determine the potential for targeting PPARs for cancer therapy and cancer chemoprevention. As PPAR agonists include drugs that are used for the treatment of metabolic diseases, a more complete understanding of the roles of PPARs in cancer will aid in determining any increased cancer risk for patients undergoing therapy with PPAR agonists.

Towards universal screening for colon cancer: a cheap, reliable, noninvasive test using gene expression analysis of rectal swabs

Though colon cancer is the second leading cause of cancer deaths in the US, it is entirely preventable through early screening to detect and remove adenomatous polyps. Colonoscopy has long been regarded as the "gold standard" but is expensive, invasive, and uncomfortable, and only about half those considered at risk for colon cancer currently submit to colonoscopy or to less reliable alternatives such as fecal occult blood test. Here we describe the use of gene expression analysis to detect altered expression of certain genes associated with not only colon cancer but also polyps. The analysis can be performed on rectal swabs, with specimens provided in a routine doctor's office visit. The existence of this cheap and simple test, together with an active program to encourage individuals to submit to screening, could help eradicate colon cancer.

Serum biomarkers which correlate with failure to respond to immunotherapy and tumor progression in a murine colorectal cancer model

PURPOSE

To advance our understanding of mechanisms involved in tumor progression/regression, a CT26 colorectal mouse model treated intra-tumorally with DISC-herpes simplex virus as immunotherapy was used in the discovery and validation phases to investigate and ultimately identify biomarkers correlating with the failure to respond to immunotherapy.

EXPERIMENTAL DESIGN

For the discovery phase, serum protein/peptide profiles of a retrospective sample collection (total n=70) were analyzed using MALDI-TOF-MS combined with artificial neural networks. Following identification of the key predictive peptides using ESI-MS/MS, validation of the identified proteins was carried out on serum and tissues collected in an independent sample set (total n=60).

RESULTS

Artificial neural network analysis resulted in four discriminatory peaks with an accuracy of 86%, sensitivity of 90% and specificity of 81% between the progressor/regressor groups. Three of the identified discriminatory markers were upregulated and demonstrated a positive correlation with tumor progression following DISC-herpes simplex virus therapy. Immunovalidation studies corroborated the MALDI-TOF-MS findings. Immunohistochemistry revealed that serum amyloid A-1 and serum amyloid P produced in the liver localized intracellularly in CT26 tumor tissue.

CONCLUSIONS

MALDI-TOF-MS and BI analysis of the serum proteome of tumor-bearer mice undergoing immunotherapy, identified biomarkers associating with "failure to respond" and biological arrays confirmed these findings.

Family history of colorectal cancer: a determinant of advanced adenoma stage or adenoma multiplicity?

A family history of colorectal cancer may increase colorectal cancer risk by influencing adenoma growth or enhancing the formation of new lesions. Data of men from the prospective Health Professionals Follow-Up Study who underwent an endoscopy between 1986 and 2004 were used to evaluate whether a family history of colorectal cancer is associated with adenoma multiplicity or advanced adenoma stage (> or =1 cm, histology with villous component or carcinoma in situ). 21.4% of the 3,881 adenoma patients and 13.9% of the 24,959 adenoma-free men had a first-degree relative with colorectal cancer. Thousand four hundred and ninety-six men were classified as having advanced and 1,507 as having nonadvanced adenomas. Six hundred and twenty-two men had multiple and 1,985 had single adenomas in the distal colon and rectum. A family history of colorectal cancer was similarly associated with advanced and nonadvanced adenomas [multivariable odds ratio (OR) (95% confidence interval): advanced vs. nonadvanced, 0.98 (0.82-1.17), advanced vs. adenoma-free: 1.67 (1.47-1.91), nonadvanced vs. adenoma-free: 1.70 (1.49-1.94)], although potential differences according to adenoma location were seen. A family history of colorectal cancer was more strongly associated with multiple distally located adenomas [odds ratio (95% confidence interval): multiple vs. single, 1.35 (1.09-1.68), multiple vs. no distally located adenomas: 2.02 (1.67-2.44), single vs. no distally located adenomas: 1.49 (1.32-1.68)]. The number of adenomas was also positively associated with a family history of colorectal cancer. Our findings suggest that at the population level, heritable factors may be more important in earlier stages of adenoma formation than at stages of adenoma advancement for at least distally located adenomas.

Biomarkers correlate with colon cancer and risks: a preliminary study

PURPOSE

We previously reported that gene expression analysis of biopsies of normal-appearing large intestinal mucosa can distinguish individuals with colonic cancer and many individuals at risk for colon cancer from controls. The purpose of this study was to determine whether noninvasively removed rectal swabs can identify individuals with colon cancer or risk of colon cancer as effectively as we previously demonstrated using biopsies.

METHODS

Rectal mucosa cells were removed by rectal swabs, and their gene expression profiles were compared with those of biopsies removed by colonoscopy. Expression of 16 genes in the rectal mucosa of 12 individuals with colon cancer, 25 with polyps, 37 with family or self-reported cancer history, and 23 controls was measured by real-time reverse transcription-polymerase chain reaction.

RESULTS

We found similar results using rectal swabs and biopsies. Groups of individuals with or at risk for cancer showed an altered gene expression profile compared with controls. Moreover, each of the 12 cancer patients showed altered expression relative to the mean of controls.

CONCLUSIONS

Gene expression analysis using rectal swabs may provide a convenient way to screen for colon cancer.

TGF-alpha expression as a potential biomarker of risk within the normal-appearing colorectal mucosa of patients with and without incident sporadic adenoma

BACKGROUND

Transforming growth factor-alpha (TGF-alpha), a stimulatory growth factor and member of the epidermal growth factor family, is a mediator of oncogenesis and malignant progression in colorectal carcinogenesis. Limited evidence suggests its utility as a growth-related biomarker of risk for colorectal cancer.

METHODS

We measured expression of TGF-alpha in biopsies of normal-appearing colorectal mucosa using automated immunohistochemistry and quantitative image analysis in a subsample of 29 cases and 31 controls from a colonoscopy-based case-control study (n = 203) of biomarkers of risk for incident sporadic colorectal adenoma. Diet, lifestyle, and medical history were assessed with validated questionnaires.

RESULTS

TGF-alpha expression in the rectum was 51% higher in cases compared with controls (P = 0.05) and statistically significantly associated with accepted risk factors for colorectal neoplasms (36% lower among nonsteroidal anti-inflammatory drug users, 49% lower among women using hormone replacement therapy, 79% higher among persons with a family history of colorectal cancer).

CONCLUSIONS

TGF-alpha expression in the normal-appearing rectal mucosa shows promise as an early, potentially modifiable biomarker of risk for colorectal cancer.

Serum amyloid A: an acute-phase protein involved in tumour pathogenesis

The synthesis of acute-phase protein serum amyloid A (SAA) is largely regulated by inflammation- associated cytokines and a high concentration of circulating SAA may represent an ideal marker for acute and chronic inflammatory diseases. However, SAA is also synthesized in extrahepatic tissues, e.g. human carcinoma metastases and cancer cell lines. An increasing body of in vitro data supports the concept of involvement of SAA in carcinogenesis and neoplastic diseases. Accumulating evidence suggests that SAA might be included in a group of biomarkers to detect a pattern of physiological events that reflect the growth of malignancy and host response. This review is meant to provide a broad overview of the many ways that SAA could contribute to tumour development, and accelerate tumour progression and metastasis, and to gain a better understanding of this acute-phase reactant as a possible link between chronic inflammation and neoplasia.

p16INK4a gene promoter hypermethylation in mucosa as a prognostic factor for patients with colorectal cancer

Low gene expression of folylpolyglutamate synthase (FPGS) in colorectal mucosa correlates with low folate levels and poor survival of colorectal cancer (CRC) patients. Because gene-specific hypermethylation is affected by the folate level, the hypermethylation status in mucosa may also be linked to clinical outcome of CRC patients. The tumor suppressor gene p16INK4a (p16) regulates the cell cycle and angiogenic switch. In human neoplastic tissues, the main mechanism of p16 inactivation is promoter methylation. The aim of the study was to determine whether hypermethylation of the p16 promoter could be detected in mucosa of CRC patients (n = 181) and to analyze if hypermethylation was related to survival. The relation between p16 hypermethylation and expression of FPGS and two other folate-associated genes, reduced folate carrier 1 (RFC-1), and thymidylate synthase (TS), was analyzed (n = 63). The results showed that p16 was hypermethylated in 65 (36%) of the mucosa samples and that hypermethylation was age-related (P = 0.029). After adjustment for known risk factors, Cox regression analysis showed that Dukes' A-C patients with p16 hypermethylation in mucosa had an increased risk of cancer-related death (hazard ratio = 2.9, P = 0.007) and shorter disease-free survival (hazard ratio = 2.5, P = 0.015) compared with patients with no p16 hypermethylation. RFC-1 and FPGS gene expression levels were significantly correlated in patients lacking p16 hypermethylation in mucosa (P = 0.0003), but not at all correlated in patients having hypermethylation in mucosa (P = 1.0). In conclusion, p16 hypermethylation in mucosa of CRC patients was identified as an independent prognostic parameter for cancer-specific survival as well as an independent predictor of DFS. The results suggest that there might be a connection between folate-associated gene expression and p16 methylation status.

Role of peroxisome-proliferator-activated receptor beta/delta (PPARbeta/delta) in gastrointestinal tract function and disease

PPARbeta/delta (peroxisome-proliferator-activated receptor beta/delta) is one of three PPARs in the nuclear hormone receptor superfamily that are collectively involved in the control of lipid homoeostasis among other functions. PPARbeta/delta not only acts as a ligand-activated transcription factor, but also affects signal transduction by interacting with other transcription factors such as NF-kappaB (nuclear factor kappaB). Constitutive expression of PPARbeta/delta in the gastrointestinal tract is very high compared with other tissues and its potential physiological roles in this tissue include homoeostatic regulation of intestinal cell proliferation/differentiation and modulation of inflammation associated with inflammatory bowel disease and colon cancer. Analysis of mouse epithelial cells in the intestine and colon has clearly demonstrated that ligand activation of PPARbeta/delta induces terminal differentiation. The PPARbeta/delta target genes mediating this effect are currently unknown. Emerging evidence suggests that PPARbeta/delta can suppress inflammatory bowel disease through PPARbeta/delta-dependent and ligand-independent down-regulation of inflammatory signalling. However, the role of PPARbeta/delta in colon carcinogenesis remains controversial, as conflicting evidence suggests that ligand activation of PPARbeta/delta can either potentiate or attenuate this disease. In the present review, we summarize the role of PPARbeta/delta in gastrointestinal physiology and disease with an emphasis on findings in experimental models using both high-affinity ligands and null-mouse models.

Field defects in progression to gastrointestinal tract cancers

A field of defective tissue may represent a pre-malignant stage in progression to many cancers. However, field defects are often overlooked in studies of cancer progression through assuming tissue at some distance from the cancer is normal. We indicate, however, the generality of field defects in gastrointestinal cancers, including cancers of the oropharynx, esophagus, stomach, bile duct, pancreas, small intestine and colon/rectum. Common features of these field defects are reduced apoptosis competence, aberrant proliferation and genomic instability. These features are often associated with high bile acid exposure and may explain the association of dietary-related factors with cancer progression.

Distinct changes of dendritic cell number and IL-12 mRNA level in adjacent mucosa throughout the colorectal adenoma-carcinoma sequence

Adjacent mucosa may reflect the conflicting of host factors in response to the establishment or invasion of cancers. Characterization of anti-tumor immunity in this region may add help in understanding the immune-related mechanisms of colorectal carcinoma (CRC). In this study, adjacent non-tumor mucosa from 36 patients with colorectal adenoma (CRA), 26 with CRC and normal mucosa from 15 health controls were included, immune cell populations of dendritic cell, lymphocyte and macrophage were characterized with immunohistochemistry (IHC) and tissue messenger RNA (mRNA) levels of Th1 cytokines interferon (IFN)-gamma and its upstream inducers interleukin (IL)-12 and IL-18 were quantified with real-time PCR; In addition, dendritic cell differentiation and function inhibitors cyclooxygenase-2 (COX-2) and IL-6 mRNA levels were also quantified. By IHC, a significant decreased dendritic cell density in the non-tumor mucosa adjacent to CRC was detected (P < 0.05) as compared to the normal controls or adjacent mucosa of CRA. The grading scores for lymphocyte number in the adjacent mucosa of CRA and CRC were gradually non-statistically increased, while the grading scores for macrophages number was not changed. By quantitative real-time PCR, distinct local cytokine gene expression profile was demonstrated. In which, the Th1 cytokines, particularly IL-12, were increased in adjacent mucosa of CRA, but all significantly decreased in adjacent mucosa of CRC. In addition, the mRNA levels of IL-6 and COX-2 were significantly higher in adjacent mucosa of CRC than that in adjacent mucosa of CRA (both P < 0.05). Therefore, dendritic cell functional changes could be one of the important mechanisms for altered anti-tumour immunity in the adjacent non-tumor mucosa throughout adenoma-carcinoma sequence. The increased COX-2 and IL-6 might contribute to dendritic cell functional defect in adjacent mucosa of CRC.

The effect of body weight on altered expression of nuclear receptors and cyclooxygenase-2 in human colorectal cancers

Background

Epidemiological studies on risk factors for colorectal cancer (CRC) have mainly focused on diet, and being overweight is now recognized to contribute significantly to CRC risk. Overweight and obesity are defined as an excess of adipose tissue mass and are associated with disorders in lipid metabolism. Peroxisome proliferator-activated receptors (PPARs) and retinoid-activated receptors (RARs and RXRs) are important modulators of lipid metabolism and cellular homeostasis. Alterations in expression and activity of these ligand-activated transcription factors might be involved in obesity-associated diseases, which include CRC. Cyclooxygenase-2 (COX-2) also plays a critical role in lipid metabolism and alterations in COX-2 expression have already been associated with unfavourable clinical outcomes in epithelial tumors. The objective of this study is to examine the hypothesis questioning the relationship between alterations in the expression of nuclear receptors and COX-2 and the weight status among male subjects with CRC.

Method

The mRNA expression of the different nuclear receptor subtypes and of COX-2 was measured in 20 resected samples of CRC and paired non-tumor tissues. The association between expression patterns and weight status defined as a body mass index (BMI) was statistically analyzed.

Results

No changes were observed in PPARγ mRNA expression while the expression of PPARδ, retinoid-activated receptors and COX-2 were significantly increased in cancer tissues compared to normal colon mucosa (P ≤ 0.001). The weight status appeared to be an independent factor, although we detected an increased level of COX-2 expression in the normal mucosa from overweight patients (BMI ≥ 25) compared to subjects with healthy BMI (P = 0.002).

Conclusion

Our findings show that alterations in the pattern of nuclear receptor expression observed in CRC do not appear to be correlated with patient weight status. However, the analysis of COX-2 expression in normal colon mucosa from subjects with a high BMI suggests that COX-2 deregulation might be driven by excess weight during the colon carcinogenesis process.

Expression and significances of interleukin-8 and interleukin-15 in colonic mucosa of colon cancer patients

AIM: To investigate the expression of interleukin-8 (IL-8) and IL-15 in colonic mucosa from colon cancer patients and study their relationships with colon cancer.

METHODS: Immunohistochemical technique was used to detect the expression of IL-8 and IL-15 in 66 patients with colon cancer.

RESULTS: The positive rates of IL-8 and IL-15 were 66.7% (44/66) and 60.6% (40/66), respectively. Significant correlations existed between expression of IL-8, IL-15 and the following factors: clinical stages (IL-8: r = 0.437, P = 0.006; IL-15: r = 0.317, P = 0.014), invasive depth (IL-8: r = 0.332, P = 0.003; IL-15: r = 0.312, P = 0.015), regional lymph node metastasis (IL-8: r = 0.316, P = 0.042; IL-15: r = 0.236, P = 0.017), histologic grades (IL-8: r = 0.826, P = 0.0001; IL-15: r = 0.368, P = 0.001).

CONCLUSION: Detection of IL-8 and IL-15 expression is helpful in assessing the malignant degrees of colon cancer.

Proteomic analysis reveals field-wide changes in protein expression in the morphologically normal mucosa of patients with colorectal neoplasia

Models for the pathogenesis of colorectal cancer tend to focus on the localized lesion, with less attention paid to changes in normal-appearing mucosa. Here we used two-dimensional gel electrophoresis and mass spectrometry to define patterns of protein expression in morphologically normal colonic mucosa from 13 healthy subjects, 9 patients with adenomatous polyps, and 9 with cancer. Tumor samples were also compared with the normal mucosa. Systematic gel comparisons identified a total of 839 spots that differed significantly between one or more groups (P < 0.05). Principle component analysis indicated that the first three components accounted for approximately 37% of the total variation and provided clear evidence that flat mucosa from healthy subjects differed significantly from that of patients with polyps or cancer. Sixty-one proteins differed significantly between mucosa from healthy subjects and all other tissue types, and 206 differed significantly between healthy mucosa and polyp mucosa. Several of the proteins showing significant underexpression in tumor tissue were cytokeratins and other cytoskeletal components. In contrast, cytokeratins, including several isoforms of cytokeratin 8, were overexpressed in apparently normal mucosa from polyp and cancer patients compared with mucosa from healthy subjects. These findings indicate that protein expression in the apparently normal colonic mucosal field is modified in individuals with neoplastic lesions at sites distant from the lesion. Recognition and further characterization of this field effect at the molecular level may provide protein biomarkers of susceptibility to colorectal cancer and facilitate development of hypotheses for the role of diet and other environmental factors in its causation.

Altered gene expression in normal colonic mucosa of individuals with polyps of the colon

PURPOSE

Expression levels of many genes are altered in colon cancer, relative to normal colonic mucosa. We recently reported that such differences also exist between grossly normal colonic mucosa of individuals with and without colon cancer, and between individuals with and without a family history of colon cancer. Here we report a study of individuals with no cancer but with polyps in the transverse, ascending/descending, or rectosigmoid colon.

METHODS

Biopsies of grossly normal-appearing colonic mucosa from the rectosigmoid colon were taken from individuals with polyps, with or without personal/family history of colon cancer, and gene expression profiles compared with those from biopsies of control patients, with no polyps or known personal/family history. A global expression analysis was conducted of the same 15 genes used in our previous studies.

RESULTS

We found significant differences in gene expression in normal-appearing rectosigmoid colonic mucosa between individuals with polyps and controls, regardless of whether personal or family history of cancer was present.

CONCLUSIONS

Alterations in gene expression patterns in morphologically normal-appearing colonic mucosa are associated with the presence of adenomatous polyps. Prospective studies will be required to determine whether these alterations in gene expression can be used to predict risk of developing colon cancer.