Jiayuan Peng

miR-150 as a potential biomarker associated with prognosis and therapeutic outcome in colorectal cancer

Background MicroRNAs (miRNA) have potential as prognostic biomarkers and therapeutic targets in cancer. A study was undertaken to investigate the association between miRNA expression patterns and the prognosis and therapeutic outcome of colorectal cancer (CRC). Methods miRNA expression profiling in tumour, adenoma and normal colorectal tissues was performed to identify tumour-related miRNAs in the course of colorectal malignant changes. Quantitative reverse transcription PCR (qRT-PCR) assays were used to measure tumour-related miRNA and to assess its association with survival and response to adjuvant chemotherapy in 239 patients. In addition, to validate the findings, associations of the tumour-related miRNA with clinical characteristics of CRC were analysed in 185 patients by in situ hybridisation (ISH) analysis. Results Only one miR-150 was found to show a decrease in expression levels in the three tissue groups (normal, adenoma and cancer tissue) in parallel with increasing carcinogenesis of the colorectal tissue. In both ISH and qRT-PCR analysis, tumour tissue had reduced levels of miR-150 expression compared with paired non-cancerous tissue, which indicated that the levels of miR-150 expression were associated with CRC. Moreover, patients whose tumours had low miR-150 expression had shorter survival and a worse response to adjuvant chemotherapy than patients whose tumours had high miRNA expression. Conclusions The miR-150 expression status of patients with CRC is associated with survival and response to adjuvant chemotherapy. It is suggested that miR-150 should be considered as a potential biomarker associated with the prognosis and therapeutic outcome in CRC.

Proteomics Identification of Desmin as a Potential Oncofetal Diagnostic and Prognostic Biomarker in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide and has poor prognosis. To identify the oncofetal proteins involved in CRC carcinogenesis, differentially expressed proteins among fetal colorectal tissues, CRC, and the paired tumor-adjacent normal colorectal tissues were investigated by a two-dimensional gel electrophoresis and MALDI-TOF/TOF-based proteomics approach. 42 protein spots were differentially expressed among these tissues, and 22 proteins were identified by MS analysis. Desmin and zinc finger protein 829 were found to be elevated in CRC tissue and fetal colorectal tissue compared with normal colorectal tissue. The elevated expression of desmin in CRC tissue and different developmental stages of fetus colon was confirmed by RT-PCR and Western blot analysis. Immunohistochemical analysis showed that the elevated expression of desmin was correlated with the severity and differentiation of CRC and decreased survival rate of CRC patients. Finally by developing a highly sensitive immunoassay, desmin could be detected in human serum and was significantly elevated in CRC patients compared with healthy volunteers. We propose that desmin be considered a potential oncofetal serum tumor marker for CRC that may have significance in the detection of patients with CRC.

Elevated oncofoetal miR-17-5p expression regulates colorectal cancer progression by repressing its target gene P130

MicroRNAs (miRNAs) are essential for regulating normal embryonic development and carcinogenesis. Here we report that miR-17-5p, an oncofoetal miRNA, is a key regulator of colorectal cancer progression. We show that miR-17-5p is an oncogenic miRNA that regulates tumorigenesis and progression by targeting the gene encoding P130 and subsequently activating the Wnt/β-catenin pathway. Using specimens from two large cohorts of colorectal cancer patients, we found that patients whose tumours had high miR-17-5p expression had shorter overall survival rates but showed a better response to adjuvant chemotherapy than did patients whose tumours had low miRNA expression. We also observed a strong inverse correlation between miR-17-5p and P130 expression. The current findings suggest that miR-17-5p is a crucial determinant of colorectal cancer progression.

Human embryonic stem cells and metastatic colorectal cancer cells shared the common endogenous human microRNA-26b

The increase in proliferation and the lack of differentiation of cancer cells resemble what occur in the embryonic stem cells during physiological process of embryogenesis. There are also striking similarities in the behaviour between the invasive placental cells and invasive cancer cells. In the present study, microarrays were used to analyse the global expression of microRNAs in a human embryonic stem cell line (i.e. HUES‐17) and four colorectal cancer (CRC) cell lines (i.e. LoVo, SW480, HT29 and Caco‐2) with different metastatic potentialities. Only the expression of miR‐26b was significant decreased in HUES‐17s and LoVo cells, compared with other three cell lines (P < 0.01). The quantitative real‐time PCR analysis confirmed the results of the microarray analysis. Overexpression of miR‐26b expression by miR‐26 mimics transfection and led to the significant suppression of the cell growth and the induction of apoptosis in LoVo cells in vitro, and the inhibition of tumour growth in vivo. Moreover, the potential targets of miR‐26b was predicted by using bioinformatics, and then the predicted target genes were further validated by comparing gene expression profiles between LoVo and NCM460 cell lines. Four genes (TAF12, PTP4A1, CHFR and ALS2CR2) with intersection were found to be the targets of miR‐26b. MetaCore network analysis further showed that the regulatory pathways of miR‐26b were significantly associated with the invasiveness and metastasis of CRC cells. These data suggest that miR‐26b might serve as a novel prognostic factor and a potential therapeutic target for CRC.

Heterogeneous nuclear ribonucleoprotein A1 is identified as a potential biomarker for colorectal cancer based on differential proteomics technology.

Colorectal cancer (CRC) is the third most common cancer worldwide and has poor prognosis. To identify the proteins involved in colorectal carcinogenesis, we employed 2-DE and MALDI-TOF/TOF-based proteomics approach to study the differentially expressed proteins in tumor and adjacent nontumor tissue samples. Samples from 10 colorectal patients were analyzed. Of the 7 significantly and consistently altered proteins identified, hnRNP A1 was one of the most significantly altered proteins and its overexpression was confirmed using RT-PCR and Western blot analyses. Immunohistochemical examination showed that the enhanced expression of hnRNP A1 was correlated with the increasing severity of colorectal tissue and the progression of the colorectal cancer, as well as UICC (International Union against Cancer) staging, histo-differentiation, recurrence and decreased survival. By developing a highly sensitive immunoassay, hnRNP A1 could be detected in human serum and was significantly elevated in CRC patients compared with healthy volunteers. We proposed that hnRNP A1 could be considered as a novel serum tumor marker for CRC that may have significance in the detection and in the management of patients with this disease. Knockdown of hnRNP A1 expression by RNA interference led to the significant suppression of the cell growth in colorectal cancer SW480 cells in vitro. These data suggested that hnRNP A1 may be a potential biomarker for early diagnosis, prognosis, and monitoring in the therapy of colorectal cancer. Further studies are needed to fully assess the potential clinical value of this biomarker candidate.

Searching for serum tumor markers for colorectal cancer using a 2-D DIGE approach

Identification of specific protein markers for colorectal cancer (CRC) could provide a basis for its early diagnosis and detection, as well as clues to the molecular mechanisms governing cancer progression. In the present study, 2‐D DIGE coupled with MS was used to screen for biomarker candidates in the serum proteome of ten human CRC samples and ten healthy control samples. After pooling identical amounts of serum proteins (based on total protein concentration), albumin/IgG was depleted under partially denaturing conditions. Subsequently, the serum samples were labeled with three different CyDyes, and separated by 2‐D DIGE. After analysis with the biological variation analysis module of the DeCyder software, only three spots were found to be significantly elevated in all patient groups (with ratios from 1.52 to 9.08), whereas five spots were significantly down‐regulated in patients (with ratios from −1.23 to −10.21) (t‐test; p<0.05). Finally, two potential biomarkers, Transaldolase 1 and thyroid receptor interactor, were chosen for validation and analysis by ELISA with the serum of 30 CRC patients and 30 healthy controls. The serum levels of the two proteins correlated well with the 2‐D DIGE results. Thus, 2‐D DIGE approaches show great promise for biomarker discovery in CRC.

Ultra-High Performance Liquid Chromatography–Mass Spectrometry for the Metabolomic Analysis of Urine in Colorectal Cancer

We report here the results of a pilot study in which ultra-high performance liquid chromatography/time-of-flight–mass spectrometry (UPLC/TOF–MS) and multivariate statistical analysis (supervised partial least squares discriminant analysis, PLS-DA) were applied for urinary metabolite profiling and data interpretation. The results of the PLS-DA indicated that the metabolic pattern as a whole was significantly different between the groups of preoperative colorectal cancer (CRC) patients, postoperative CRC patients, and healthy volunteers, respectively. The preoperative group of patients showed significantly increased levels of low-molecular weight compounds (LMC) MW 283 and MW 234 in comparison to the group of healthy volunteers group. After the operation, the levels of these two LMC significantly decreased. These preliminary results suggest that the UPLC–MS-based method coupled with pattern recognition will likely lead to procedures with the potential to be clinically applicable for the diagnosis of CRC and, consequently, to an improvement in patient prognosis.

NIRF is frequently upregulated in colorectal cancer and its oncogenicity can be suppressed by let-7a microRNA

Np95 ICBP90 RING finger (NIRF) is essential for the regulation of cell proliferation and has been implicated in tumorigenesis. However, the role of NIRF in colorectal cancer (CRC) remains unclear. In this study, we demonstrated that NIRF expression was aberrantly increased in CRC tissues and associated with poor overall survival. Bioinformatics analysis indicated that NIRF was a putative target of the microRNA let-7a, which was confirmed by luciferase reporter assay. We then demonstrated in vitro that enforced expression of let-7a, or knockdown of NIRF, led to reduced CRC cell proliferation due to cell cycle arrest at the G0/G1 phase and reduced cell migration. Finally, an in vivo tumorigenicity assay in nude mice showed that synthetic let-7a suppressed NIRF expression and reduced tumor growth. Taken together, our results provide new evidence that NIRF has an oncogenic role in CRC. This opens up the possibility of targeting NIRF and let-7a for CRC therapy.

Comprehensive gene and microRNA expression profiling reveals the crucial role of hsa-let-7i and its target genes in colorectal cancer metastasis.

Accumulating evidence has demonstrated that miRNAs play important roles in the occurrence and development of colorectal cancer (CRC). However, whether miRNAs are associated with the metastasis of CRC remains largely unexplored. The aim of the current study is to profile miRNAs in different CRC metastatic cell lines to identify the biomarkers in CRC metastasis. Gene and miRNA expression profiling was performed to analyze the global expression of mRNAs and miRNAs in the four human CRC cell lines (LoVo, SW480, HT29 and Caco-2) with different potential of metastasis. Expression patterns of mRNAs and miRNAs were altered in different CRC cell lines. By developing an integrated bioinformatics analysis of gene and miRNA expression patterns, hsa-let-7i was identified to show the highest degree in the microRNA-GO-network and microRNA-Gene-network. The expression level of hsa-let-7i was further validated by qRT-PCR in CRC cells. In addition, the targets of hsa-let-7i were predicted by two programs TargetScan and PicTar, and target genes were validated by expression profiling in the most epresentative LoVo and Caco-2 cell lines. Eight genes including TRIM41, SOX13, SLC25A4, SEMA4F, RPUSD2, PLEKHG6, CCND2, and BTBD3 were identified as hsa-let-7i targets. Our data showed the power of comprehensive gene and miRNA expression profiling and the application of bioinformatics tools in the identification of novel biomarkers in CRC metastasis.

A pilot study of gas chromatograph/mass spectrometry-based serum metabolic profiling of colorectal cancer after operation

Colorectal cancer (CRC) is mainly depended on the radical operation, the changing energy metabolism after operation reflects the extent, the magnitude, and the degree of surgical trauma. The aim of this study was to analyse the biochemical perturbation in the serum of CRC after operation and to evaluate their involvement in the progression of CRC. Gas chromatograph-mass spectrometry (GC-MS) in combination with pattern recognition techniques (Partial least squares discriminant analysis, supervised clustering analysis) was used to analyze serum metabolome in 30 CRC patients. A 34 endogenous metabolites included amino acid, fatty acid, carbohydrate and other intermediate metabolites were identified. Partial least squares discriminant analysis based on these metabolites discriminated preoperative from postoperative CRC group. Compared with preoperative CRC patients group, decreases in l-valine, 5-oxo-l-proline, 1-deoxyglucose, d-turanose, d-maltose, arachidonic acid and hexadecanoic acid levels and increases in l-tyrosine levels were observed in postoperative CRC patients group. The result demonstrated the GC-MS technique is an valuable tool for the characterization of the metabolic perturbation, and the metabolomic study will certainly benefit for monitoring the nutrition state of CRC patients, the prognosis and therapy evaluation of CRC patients after operation.