Unknown,Transcriptomics,Genomics,Proteomics

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A Gene Expression Signature for Chemoradiosensitivity of Colorectal Cancer Cells

ABSTRACT: In this study, we use cancer cell lines to investigate the molecular differences between resistant and responsive colorectal cancer cells. Since the treatment of patients with locally advanced rectal cancers involves chemoradiotherapy (CT/RT), we specifically implemented an in vitro protocol that mimics this clinical setting. We anticipate that this analysis will unveil relevant pathways underlying the resistance of rectal cancers to CT/RT, and enable the identification of novel therapeutic target genes. 12 colorectal cancer (CRC) cell lines were obtained from the ATCC, and cultured in the respective tissue culture medium as recommended by the ATCC: Caco-2, HT-29, LS411N, LS513, LS1034, SW403, SW480, SW620, SW837, SW1116, SW1463, and WiDr. For each cell line, RNA was independently isolated at three different passages, and hybridized to a gene expression array. Accordingly, there are three biological triplicates per cell line. Additionally, SW480 (triplicate), SW837 (triplicate), and Caco-2 (duplicate) were cultured in RPMI.

ORGANISM(S): Homo sapiens

SUBMITTER: Melanie Spitzner

PROVIDER: E-GEOD-20298 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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A gene expression signature for chemoradiosensitivity of colorectal cancer cells.

Spitzner Melanie M Emons Georg G Kramer Frank F Gaedcke Jochen J Rave-Fränk Margret M Scharf Jens-Gerd JG Burfeind Peter P Becker Heinz H Beissbarth Tim T Ghadimi B Michael BM Ried Thomas T Grade Marian M

International journal of radiation oncology, biology, physics 20101101 4

<h4>Purpose</h4>The standard treatment of patients with locally advanced rectal cancers comprises preoperative 5-fluorouracil-based chemoradiotherapy followed by standardized surgery. However, tumor response to multimodal treatment has varied greatly, ranging from complete resistance to complete pathologic regression. The prediction of the response is, therefore, an important clinical need.<h4>Methods and materials</h4>To establish in vitro models for studying the molecular basis of this heterog ...[more]

PMID: 20970032

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Project description:Colorectal cancer is the third most common cancer worldwide, with 1.4 million people diagnosed in 2012 according to GLOBOCAN 2012. 95% of the colon cancer cases are that of adenocarcinomas. Removal of high-risk adenomas and tumors at early stage of colorectal cancer (CRC) can prevent its onset/progression into higher grades of cancer. The prognosis of colorectal cancer and the stage of diagnosis are closely correlated. 5-year survival rate is observed among 90% patients when diagnosed early and in less than 10% when the metastases develop. This makes the implementation of screening methods aimed at early detection paramount for reduced incidence and mortality rate. Adenocarcinomas are the cancers originating from the gland forming cells of the colon and rectal lining and are known to be the most common type of colorectal cancer. The current diagnosis options for colorectal cancers are limited to biopsy, stool tests and other laboratory tests, barium enema based imaging and other imaging techniques, colonoscopy and other endoscopic procedures which are time consuming. In this study, we used proteomics approach with an aim to identify protein biomarkers which can aid in early detection of colon adenocarcinomas to be precise. Proteins from tumor tissue of colon adenocarcinoma subjects (n=11) and their matched controls were subjected to 4-plex iTRAQ labelling followed by off-gel fractionation prior to LC-MS/MS run. The mass spectrometry data was analysed independently using two different analysis software - Spectrum Mill (SM) and Trans Proteome Pipeline (TPP). The proteins identified using either SM and/or TPP were subjected to pathway analysis using the Database for Annotation, Visualization and Integrated Discovery (DAVID) v6.8 and the proteins common between the two analyses were compared with the data from CPTAC portal and Human Protein Atlas. The expression level of the shortlisted panel of proteins was studied in brain cancers as a non-colon adenocarcinoma control group and validated using MRM approach. A list of 285 unique proteins was identified to be significantly dysregulated in colon adenocarcinoma as compared to its matched controls. These proteins were found to be involved in glycolysis, pentose phosphate pathway, biosynthesis of amino acids, protein processing, spliceosome, proteosome, focal adhesion and proteoglycans in cancer. 94 of the 285 proteins were identified by both- SM and TPP. 34 of these 94 proteins were found to be dysregulated with same trend as that in data reported on CPTAC portal and 9 of these 34 proteins were validated using MRM approach. The proteins identified from this study could be validated further to investigate the role of these proteins as potential biomarkers for early detection of colon adenocarcinoma.

Project description:Originally linked with development and differentiation, the role of microRNAs (miRNAs) in many important biological processes has emerged and dysregulation of miRNA expression has been connected with cancer pathogenesis. The association between abnormal expression levels of miRNAs and colon cancer has been mainly demonstrated in primary tumors; more recently, non-overlapping sets of oncomirs, tumour suppressor miRNAs and metastamirs have been associated with distinct stages of colo-rectal cancer (CRC) progression. In an attempt to identify changes in both miRNA and gene expression levels along the colon mucosa - primary tumor - liver metastasis- sequence and to classify miRNAs into distinct functional networks according to the expression of their anti-correlated and differentially expressed target genes, we analyzed a large set of sample-matched miRNA and mRNA expression profiles, including the complete non tumor tissue, primary carcinoma and liver metastasis sequence from 8 patients. Our study shows that the largest changes in miRNA and gene expression levels occur in normal mucosa to tumor transition and are almost stably maintained in the subsequent tumor to metastasis transition. Only a few miRNAs were differentially expressed between liver metastasis and primary carcinoma; however, miRNA expression profiles classified better primary tumors and metastases compared to mRNA profiles. By integration of miRNAs and target genes expression data, we were able to infer regulatory networks modulated by miRNAs during colorectal tumorigenesis and metastatic process, and associate them to the affected biological pathways. In particular, we identified a combination of interconnected miRNAs, up- or down-regulated during tumorigenesis, which are organized into distinct sub-networks, each of which includes several regulatory relationships with differentially expressed genes. Among them, the relationship between miR-182, up-regulated in colon cancer, and the anti-correlated ENTPD5 gene was identified for the first time and confirmed in an independent set of samples. We determined miRNA expression profile for 78 samples comprising 23 normal adjacent mucosa (N), 31 primitive colorectal cancer (T) and 24 liver metastases (M), obtained from 45 patients who underwent surgery at University of Padova (Surgery Branch, Department of Oncological and Surgical Sciences) between March 1994 and September 2008. This dataset included 24 samples belonging to 8 patients with matched samples (N, T and M) from the same patients. We also examined the expression profiles for 80 samples, comprising 23 N, 30 T, 27 M, and including 27 per-patient matched samples from 9 patients. Considering both miRNAs and genes expression experiments, we obtained a set of 77 samples (23N, 30T, 24M) with matched miRNAs and genes expression data from the same biological sample, to reconstruct post-transcriptional regulatory networks.

Project description:Background: MicroRNAs (miRNAs) are small, non-coding, RNA molecules which regulate numerous cellular processes. Specific miRNA may be abnormally down-regulated or up-regulated in colorectal cancer and have been found associated with prognosis or response to treatments. However, no study has ever addressed their predictive role in rectal cancer. Therefore, we used microarray technology and RT-PCR to profile miRNA expression patterns in patients (pts) with rectal cancer, with the aim to identify a specific M-bM-^@M-^\signatureM-bM-^@M-^] associated with pathological complete response after neoadjuvant chemo-radiotherapy. Methods: 38 pts with locally advanced rectal cancer (cT3-4/N+) were treated with capecitabine-oxaliplatin and pelvic conformal radiotherapy (45 cGy) followed by surgery (after 6-8 weeks). Pathologic response was scored according to the tumor regression grade (TRG) scale. MiRNA expression profile was analysed by microarray on fresh frozen biopsies obtained before treatment start and confirmed by RT-PCR. The correlation between miRNA expression profile and the TRG coded as TRG1 (pathologic Complete Response-pCR) versus TRG >1 (no pCR) was assessed by statistical analysis methods specifically designed for this study. Findings: 14 miRNAs were selected by arrays analysis as differentially expressed in TRG1 pts and 13 were confirmed by RT-PCR. In particular, 11 miRNAs (miR-1183, miR-483-5p, miR-622, miR-125a-3p, miR-1224-5p, miR-188-5p, miR-1471, miR-671-5p, miR-1909*, miR-630 and miR-765) were significantly up-regulated in TRG1 pts, while 2 miRNAs were under -expressed (miR-1274b and miR-720). miR-622 and miR-630 showed 100% sensitivity and specificity in selecting TRG1 cases and were significantly correlated with EGFR (M-OM-^G2=11M-bM-^@M-"793; p= 0M-bM-^@M-"001) and TS expression (M-OM-^G2=10M-bM-^@M-"589; p= 0M-bM-^@M-"001). Interpretation: A set of 13 miRNAs is strongly associated with pathologic complete response and may represent a specific marker of response to chemo-radiotherapy in locally advanced rectal cancer. Experiments were performed on purified RNA from preoperatory biopsies of 38 patients with histological diagnosis of rectal adenocarcinoma invading through the intestinal wall and/or with pelvic lymph node involvement as evaluated by endorectal ultrasonography (uT3-T4 and/or uN+). Patients were treated with neoadjuvant chemo-radiotherapy (capecitabine + oxaliplatin in combination with 45 Gy of pelvic conformal radiotherapy). Patients have been divided in the following two groups: group A those who had obtained a pathologic complete response M-bM-^@M-^S TRG 1, including the patient without detectable disease who refused surgery, group B any pathologic response other than complete.

Dataset Information

A Gene Expression Signature for Chemoradiosensitivity of Colorectal Cancer Cells

Publications

A gene expression signature for chemoradiosensitivity of colorectal cancer cells.

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