Potential of faecal RNA in diagnosing colorectal cancer

Potential prognostic and predictive value of UBE2N, IMPDH1, DYNC1LI1 and HRASLS2 in colorectal cancer stool specimens

Colorectal cancer (CRC) is the most common gastrointestinal malignancy worldwide. The poor specificity and sensitivity of the fecal occult blood test has prompted the development of CRC-related genetic markers for CRC screening and treatment. Gene expression profiles in stool specimens are effective, sensitive and clinically applicable. Herein, a novel advantage of using cells shed from the colon is presented for cost-effective CRC screening. Molecular panels were generated through a series of leave-one-out cross-validation and discriminant analyses. A logistic regression model following reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry was used to validate a specific panel for CRC prediction. The panel, consisting of ubiquitin-conjugating enzyme E2 N (UBE2N), inosine monophosphate dehydrogenase 1 (IMPDH1), dynein cytoplasmic 1 light intermediate chain 1 (DYNC1LI1) and phospholipase A and acyltransferase 2 (HRASLS2), accurately recognized patients with CRC and could thus be further investigated as a potential prognostic and predictive biomarker for CRC. UBE2N, IMPDH1 and DYNC1LI1 expression levels were upregulated and HRASLS2 expression was downregulated in CRC tissues. The predictive power of the panel was 96.6% [95% confidence interval (CI), 88.1-99.6%] sensitivity and 89.7% (95% CI, 72.6-97.8%) specificity at a predicted cut-off value at 0.540, suggesting that this four-gene panel testing of stool specimens can faithfully mirror the state of the colon. On the whole, the present study demonstrates that screening for CRC or cancer detection in stool specimens collected non-invasively does not require the inclusion of an excessive number of genes, and colonic defects can be identified via the detection of an aberrant protein in the mucosa or submucosa.

Upregulation of Fecal Epithelial Heparanase mRNA Is Associated with Increased Ulcerative Colitis Activity and Cancerization Risk

BACKGROUND

Heparanase (HPSE) is considered to play an important role in the occurrence, development and carcinogenesis of ulcerative colitis (UC). There are no reports about the detection of HPSE mRNA in feces to predict UC activity and cancerization risk.

AIMS

To explore the feasibility and effectiveness of fecal epithelial HPSE mRNA in monitoring patients' UC activity and predicting cancer risk.

METHODS

The clinical part of the study enrolled 20 patients with UC and 20 controls. Meanwhile, a UC-induced carcinogenesis mouse model was established using a combination treatment of dimethylhydrazine and dextran sulfate sodium. Tissue expression of HPSE protein was detected by immunohistochemistry. RT-qPCR was used to detect the expression of HPSE mRNA in colonic mucosa and feces.

RESULTS

In the human study, the relative expressions of HPSE mRNA in colonic mucosa and feces were positively correlated with the Mayo score (P < 0.05), and with a significant correlation between feces and colonic mucosa (P < 0.05). In the mouse model, the relative expressions of HPSE mRNA in colonic mucosa and feces in the ulcerative colitis-associated colorectal cancer group was significantly higher than that of the UC group and the normal control group (P < 0.05), and with a significant correlation between feces and colonic mucosa (P < 0.05).

CONCLUSIONS

The relative level of HPSE mRNA was positively correlated with UC activity and cancerization. The relative level of HPSE mRNA in feces was correlated with that in colonic mucosa. The detection of HPSE mRNA in feces can be used as a new marker for disease monitoring and cancer risk prediction of UC.

Discovery of genes from feces correlated with colorectal cancer progression

Colorectal cancer (CRC) is considered to develop slowly via a progressive accumulation of genetic mutations. Markers of CRC may serve to provide the basis for decision-making, and may assist in cancer prevention, detection and prognostic prediction. DNA and messenger (m)RNA molecules that are present in human feces faithfully represent CRC manifestations. In the present study, exogenous mouse cells verified the feasibility of total fecal RNA as a marker of CRC. Furthermore, five significant genes encoding solute carrier family 15, member 4 (SLC15A4), cluster of differentiation (CD)44, 3-oxoacid CoA-transferase 1 (OXCT1), placenta-specific 8 (PLAC8) and growth arrest-specific 2 (GAS2), which are differentially expressed in the feces of CRC patients, were verified in different CRC cell lines using quantitative polymerase chain reaction. The present study demonstrated that the mRNA level of SLC15A4 was increased in the majority of CRC cell lines evaluated (SW1116, LS123, Caco-2 and T84). An increased level of CD44 mRNA was only detected in an early-stage CRC cell line, SW1116, whereas OXCT1 was expressed at higher levels in the metastatic CRC cell line CC-M3. In addition, two genes, PLAC8 and GAS2, were highly expressed in the recurrent CRC cell line SW620. Genes identified in the feces of CRC patients differed according to their clinical characteristics, and this differential expression was also detected in the corresponding CRC cell lines. In conclusion, feces represent a good marker of CRC and can be interpreted through the appropriate CRC cell lines.

Upregulation of the growth arrest-specific-2 in recurrent colorectal cancers, and its susceptibility to chemotherapy in a model cell system

Colorectal cancer (CRC) is one of the most common life-threatening malignances worldwide. CRC relapse markedly decreases the 5-year survival of patients following surgery. Aberrant expression of genes involved in pathways regulating the cell cycle, cell proliferation, or cell death are frequently reported in CRC tumorigenesis. We hypothesized that genes involved in CRC relapse might serve as prognostic indicators. We first evaluated the significance of gene sequences in the feces of patients with CRC relapse by consulting a public database. Tumorigenesis of target tissues was tested through tumor cell growth, cell cycle regulation, and chemotherapeutic efficacy. We found a highly significant correlation between CRC relapse and growth arrest-specific 2 (GAS2) gene expression. Based on cell models, the overexpressed GAS2 was associated with cellular growth rate, cell cycle regulation, and with chemotherapeutic sensitivity. Cell division was impaired by treating cells with 2-[4-(7-chloro-2-quinoxalinyloxy)phenoxy]-propionic acid (XK469), even when the cells were overexpressing GAS2. Thus, downregulation of GAS2 expression might control CRC relapse after curative resection. GAS2 could serve as a noninvasive marker from the feces of patients with prediagnosed CRC. Our findings suggest that GAS2 could have potential clinical applications for predicting early CRC relapse after radical resection, and that XK469 might impair tumor cell division by reducing GAS2 expression or blocking its cellular translocation. This will help in selecting the best therapeutic option, 5-fluorouracil in combination with XK469, for patients overexpressing GAS2 in CRC cells. Thus, GAS2 might act as a prognostic biomolecule and potential therapeutic target in patients with CRC relapse.

Use of RNA isolated from feces as a promising tool for the early detection of colorectal cancer

Colorectal cancer is one of the most common forms of cancer worldwide. Early detection would allow patients to be treated surgically and halt the progression of the disease; however, the current methods of early detection are invasive (colonoscopy and sigmoidoscopy) or have low sensitivity (fecal occult blood test). The altered expression of genes in stool samples of patients with colorectal cancer can be determined by RT-PCR. This is a noninvasive and highly sensitive technique for colorectal cancer screening. According to information gathered in this review and our own experience, the use of fecal RNA to determine early alterations in gene expression due to malignancy appears to be a promising alternative to the current detection methods and owing to its low cost could be implemented in public health services.

A predicted protein, KIAA0247, is a cell cycle modulator in colorectal cancer cells under 5-FU treatment

BACKGROUND

Colorectal cancer (CRC) is the predominant gastrointestinal malignancy and the leading cause of cancer death. The identification of genes related to CRC is important for the development of successful therapies and earlier diagnosis.

METHODS

Molecular analysis of feces was evaluated as a potential method for CRC detection. Expression of a predicted protein with unknown function, KIAA0247, was found in feces evaluated using specific quantitative real-time polymerase chain reaction. Its cellular function was then analyzed using immunofluorescent staining and the changes in the cell cycle in response to 5-fluorouracil (5-FU) were assessed.

RESULTS

Gastrointestinal tissues and peripheral blood lymphocytes ubiquitously expressed KIAA0247. 56 CRC patients fell into two group categories according to fecal KIAA0247 mRNA expression levels. The group with higher fecal KIAA0247 (n=22; ≥0.4897) had a significantly greater five-year overall survival rate than the group with lower fecal KIAA0247 (n = 30; <0.4897) (66.0 ± 11.6%; p=0.035, log-rank test). Fecal expression of KIAA0247 inversely related to CRC tumor size (Kendall's tau-b=-0.202; p=0.047). Immunofluorescent staining revealed that the cytoplasm of CRC cells evenly expresses KIAA0247 without 5-FU treatment, and KIAA0247 accumulates in the nucleus after 40 μM 5-FU treatment. In HCT116 p53(-/-) cells, which lack p53 cell cycle control, the proportion of cells in the G2/M phase was larger (13%) in KIAA0247-silent cells than in the respective shLuc control (10%) and KIAA0247-overexpressing cells (7%) after the addition of low dose (40 μM) 5-FU. Expression of three cyclin genes (cyclin A2, cyclin B1, and cyclin B2) also downregulated in the cells overexpressing KIAA0247.

CONCLUSIONS

This is the first description of a linkage between KIAA0247 and CRC. The study's data demonstrate overexpression of KIAA0247 associates with 5-FU therapeutic benefits, and also identify the clinical significance of fecal KIAA0247 in CRC.

[Advances in early diagnosis of colorectal cancer based on detection of RNAs in stool.]

Colorectal cancer (CRC) is one of the most malignant cancers in gastrointestinal tract. In China, there are increasing rates of morbidity and mortality for CRC. As the mortality is closely related to the stage of disease at time of diagnosis, early diagnosis of CRC is important. However, current techniques used for clinical diagnosis have limitations which made them difficult to achieve the early diagnosis. The detection of RNAs in stool is a newly developed noninvasive technique for early diagnosis of CRC at molecular levels. Compared with the techniques including colonoscopy, fecal occult-blood test and stool DNA-based mutation detection, diagnosis based on the detection of RNAs in stool has the advantages of low-cost and high sensitivity. Moreover, stool RNA-based techniques are able to analyze multiplexed gene expression simultaneously and monitor cancer progression dynamically. This paper introduced the feasibility of stool RNA analysis, and systematically reviewed the genes associated with stool RNA analysis, methods of RNA isolation from stool sample, and techniques for gene expression analysis in stool RNA. Finally, further applications of stool RNA-based techniques for early diagnosis of CRC were briefly discussed.

Clinical meaning of age-related expression of fecal cytokeratin 19 in colorectal malignancy

Background

Colorectal cancer (CRC) is one of the leading causes of malignant death worldwide. Because young age of onset is often considered a poor prognostic factor for CRC, it is important to identify the poor outcomes of CRC in a younger population and to consider an aggressive approach by implementing early treatment. Our aim was to specifically quantify the fecal cytokeratin 19 (CK19) transcript from CRC patients and investigate its correlation with clinical stage, tumor malignancy, and age.

Methods

The quantitation of fecal CK19 transcript was determined by a quantitative real-time reverse transcription polymerase chain in 129 CRC patients (45 younger than 60 years at diagnosis) and 85 healthy controls. The levels of CK19 protein were examined both in colonic cell lines and tissues.

Results

The analysis of 45 younger CRC patients (age ≤ 60 years) revealed that patients at the M1 stage had significantly higher expression levels of fecal CK19 mRNA when compared with healthy controls (p < 0.001) and patients at the M0 stage (p = 0.004). Additionally, the degree of consistency between the mean level of fecal CK19 mRNA and the distant metastatic rate in each age interval was up to 89% (p = 0.042).

Conclusion

These results indicate that high levels of fecal CK19 mRNA represent a potential marker for colorectal malignancy and for aggressive treatment of younger CRC patients.

Faecal ribosomal protein L19 is a genetic prognostic factor for survival in colorectal cancer

Ribosomal proteins are encoded by a gene family, members of which are overexpressed in human cancers. Many of them have been found, using oligonucleotide microarray hybridization, to be differentially expressed in the faeces of patients with various stages of col-orectal cancer (CRC). The gene encoding ribosomal protein L19 (RPL19), a prognostic marker for human prostate cancer, is differentially expressed in CRC patients. Measurement of faecal RPL19 mRNA might improve prognostic prediction for CRC patients. Using quantitative real-time reverse transcription PCR, levels of RPL19 mRNA were detected in samples of colonic tissues from 44 CRC patients, in the faeces of 54 CRC patients and 15 controls, and in 11 colonic cell lines. Seven of 24 patients with late-stage CRC (Dukes' stages C and D) expressed over 2-fold more RPL19 in colonic tumour tissues than in corresponding normal tissues (P= 0.038). The mean faecal RPL19 mRNA levels of late-staged patients were higher than those of controls (P= 0.003) and early-staged patients (P= 0.008). Patients with both high serum levels of carcinoembryonic antigen (CEA; >5 ng/mL) and high-faecal RPL19 mRNA (≥0.0069) had higher risk (odds ratio, 8.0; P= 0.015) and lower overall 48-month survival (33.8 ± 13.7%, P= 0.013). Oligonucleotide microarray hybridization analysis of faecal molecules identified gene transcripts differentially present in faeces. In conclusion, faecal RPL19 expression is associated with advanced tumour stages and addictive to serum CEA in predicting prognosis of CRC patients.

Cell exfoliation in the human colon: myth, reality and implications for colorectal cancer screening

Colonocyte exfoliation in the human colon constitutes a unique mechanism of cell population control that can undergo significant changes under different physiological and pathological conditions. Being closely related to the apoptosis and anoikis, cell exfoliation from colonic epithelium appears to be a relatively rare event in normal conditions, but its rate dramatically increases in neoplasia, when cell removal by apoptosis in situ does not function properly. Several studies show that significant numbers of exfoliated colonocytes are not lost in the faecal contents of the gut, but retained in the mucocellular layer overlying colonic mucosa. Recent observations allow hypothesizing that the mucocellular layer containing exfoliated colonocytes may gradually migrate distally, eventually leading to the accumulation of the cells exfoliated from malignant colorectal tumours on the surface of the rectal mucosa. Implications of exfoliated colonocyte analysis to colorectal cancer screening and early diagnosis are discussed.

Correlation of K-ras codon 12 mutations in human feces and ages of patients with colorectal cancer (CRC)

Colorectal cancer (CRC) is the predominant gastrointestinal malignancy and constitutes a major medical and economic burden worldwide. A thorough understanding of the oncogenes or genes related to tumorigenesis is the key to developing successful therapeutic strategies. Molecular analysis of feces constitutes a potentially potent and noninvasive method for detection of CRC. Using nested reverse transcription-polymerase chain reaction (RT-PCR) and amplified restriction fragment length polymorphism analysis, sloughed cells from the entire length of the colon and rectum were analyzed for expression of activating K-ras codon 12 mutants, which are becoming attractive targets for antisense treatment. K-ras codon 12 mutant sequences were detected in feces of 5% (1/20) of healthy controls, in feces of 41% (12/29) of CRC patients, in 10% (3/29) of isolates of tissue complementary DNA (cDNA), and in 14% (4/29) of isolates of genomic DNA. Age of patient was significantly associated with K-ras codon 12 sequences in feces: Patients with wild-type K-ras codon 12 sequences were significantly younger than those with mutated forms of K-ras codon 12. Fecal ribonucleic acid (RNA) analysis was demonstrated to be a useful for diagnosis of CRC. This technique may be suitable for screening and determining the clinical significance of active mutations of the K-ras gene in feces and would possibly be useful for identifying patients that would benefit from antisense therapy.