Metastasis is the major cause of cancer mortality. We aimed to find a metastasis-prone signature for early stage mismatch-repair proficient sporadic colorectal cancer (CRC) patients for better ...prognosis and informed use of adjuvant chemotherapy. The genome-wide expression profiles of 82 age-, ethnicity- and tissue-matched patients and healthy controls were analyzed using the Affymetrix U133 Plus 2 array. Metastasis-negative patients have 5 years or more of follow-up. A 10 × 10 two-level nested cross-validation design was used with several families of classification models to identify the optimal predictor for metastasis. The best classification model yielded a 54 gene-set (74 probe sets) with an estimated prediction accuracy of 71%. The specificity, sensitivity, negative and positive predictive values of the signature are 0.88, 0.58, 0.84 and 0.65, respectively, indicating that the gene-set can improve prognosis for early stage sporadic CRC patients. These 54 genes, including node molecules YWHAB, MAP3K5, LMNA, APP, GNAQ, F3, NFATC2, and TGM2, integrate multiple bio-functions in various compartments into an intricate molecular network, suggesting that cell-wide perturbations are involved in metastasis transformation. Further, querying the `Connectivity Map' with a subset (70%) of these genes shows that Gly-His-Lys and securinine could reverse the differential expressions of these genes significantly, suggesting that they have combinatorial therapeutic effect on the metastasis-prone patients. These two perturbagens promote wound-healing, extracellular matrix remodeling and macrophage activation thus highlighting the importance of these pathways in metastasis suppression for early-stage CRC.
High macrophage infiltration into tumours often correlates with poor prognoses; in colorectal, stomach and skin cancers, however, the opposite is observed but the mechanisms behind this phenomenon ...remain unclear. Here, we sought to understand how tumour‐associated macrophages (TAMs) in colorectal cancer execute tumour‐suppressive roles. We found that TAMs in a colorectal cancer model were pro‐inflammatory and inhibited the proliferation of tumour cells. TAMs also produced chemokines that attract T cells, stimulated proliferation of allogeneic T cells and activated type‐1 T cells associated with anti‐tumour immune responses. Using colorectal tumour tissues, we verified that TAMs in vivo were indeed pro‐inflammatory. Furthermore, the number of tumour‐infiltrating T cells correlated with the number of TAMs, suggesting that TAMs could attract T cells; and indeed, type‐1 T cells were present in the tumour tissues. Patient clinical data suggested that TAMs exerted tumour‐suppressive effects with the help of T cells. Hence, the tumour‐suppressive mechanisms of TAMs in colorectal cancer involve the inhibition of tumour cell proliferation alongside the production of pro‐inflammatory cytokines, chemokines and promoting type‐1 T‐cell responses. These new findings would contribute to the development of future cancer immunotherapies based on enhancing the tumour‐suppressive properties of TAMs to boost anti‐tumour immune responses.
Current clinical strategy for staging and prognostication of colorectal cancer (CRC) relies mainly upon the TNM or Duke system. This clinicopathological stage is a crude prognostic guide because it ...reflects in part the delay in diagnosis in the case of an advanced cancer and gives little insight into the biological characteristics of the tumor. We hypothesized that global metabolic profiling (metabonomics/metabolomics) of colon mucosae would define metabolic signatures that not only discriminate malignant from normal mucosae, but also could distinguish the anatomical and clinicopathological characteristics of CRC. We applied both high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) and gas chromatography mass spectrometry (GC/MS) to analyze metabolites in biopsied colorectal tumors and their matched normal mucosae obtained from 31 CRC patients. Orthogonal partial least-squares discriminant analysis (OPLS-DA) models generated from metabolic profiles obtained by both analytical approaches could robustly discriminate normal from malignant samples (Q 2 > 0.50, Receiver Operator Characteristic (ROC) AUC >0.95, using 7-fold cross validation). A total of 31 marker metabolites were identified using the two analytical platforms. The majority of these metabolites were associated with expected metabolic perturbations in CRC including elevated tissue hypoxia, glycolysis, nucleotide biosynthesis, lipid metabolism, inflammation and steroid metabolism. OPLS-DA models showed that the metabolite profiles obtained via HR-MAS NMR could further differentiate colon from rectal cancers (Q 2> 0.60, ROC AUC = 1.00, using 7-fold cross validation). These data suggest that metabolic profiling of CRC mucosae could provide new phenotypic biomarkers for CRC management.
Colorectal cancer (CRC) is the fourth most common cause of death from cancer in the world. The limitations of the currently available methods and biomarkers for CRC management highlight the necessity ...of finding novel markers. Metabonomics can be used to search for potential markers that can provide molecular insight into human CRC. The emergence of two-dimensional gas chromatography time of flight mass spectrometry (GC × GC/TOFMS) has comprehensively enhanced the metabolic space coverage of conventional GC/MS. In this study, a GC × GC/TOFMS was developed for the tissue-based global metabonomic profiling of CRC. A Pegasus GC × GC/TOFMS (Leco Corp., St. Joseph, MI, USA) system comprising an Agilent 7890 GC and Pegasus IV TOFMS was used for this purpose. An Agilent DB-1 (30 m × 250 μm × 0.25 μm) fused silica capillary column and a Restek Rxi®-17 (1 m × 100 μm × 0.10 μm) fused silica capillary column were used as the primary and secondary columns, respectively. The method was applied for global metabonomic profiling of matched CRC and normal tissues (
n
= 63) obtained from 31 CRC patients during surgery. An attempt was also made to compare GC × GC/TOFMS with GC/MS and NMR in similar application. The results showed that the metabotype associated with CRC is distinct from that of normal tissue and led to the identification of chemically diverse marker metabolites. Metabolic pathway mapping suggested deregulation of various biochemical processes such as glycolysis, Krebs cycle, osmoregulation, steroid biosynthesis, eicosanoid biosynthesis, bile acid biosynthesis, lipid, amino acid and nucleotide metabolism.
Fig
Workflow of GCGC/TOFMS metabonomic profiling of human colorectal cancer
Clusters of tumor cells are often observed in the blood of cancer patients. These structures have been described as malignant entities for more than 50 years, although their comprehensive ...characterization is lacking. Contrary to current consensus, we demonstrate that a discrete population of circulating cell clusters isolated from the blood of colorectal cancer patients are not cancerous but consist of tumor-derived endothelial cells. These clusters express both epithelial and mesenchymal markers, consistent with previous reports on circulating tumor cell (CTC) phenotyping. However, unlike CTCs, they do not mirror the genetic variations of matched tumors. Transcriptomic analysis of single clusters revealed that these structures exhibit an endothelial phenotype and can be traced back to the tumor endothelium. Further results show that tumor-derived endothelial clusters do not form by coagulation or by outgrowth of single circulating endothelial cells, supporting a direct release of clusters from the tumor vasculature. The isolation and enumeration of these benign clusters distinguished healthy volunteers from treatment-naïve as well as pathological early-stage (≤IIA) colorectal cancer patients with high accuracy, suggesting that tumor-derived circulating endothelial cell clusters could be used as a means of noninvasive screening for colorectal cancer. In contrast to CTCs, tumor-derived endothelial cell clusters may also provide important information about the underlying tumor vasculature at the time of diagnosis, during treatment, and throughout the course of the disease.
Introduction Conflicting data on the clinicopathological characteristics as well as prognosis and survival of signet ring cell (SRC) and mucinous adenocarcinomas (MA) of the colorectum persist. ...Methods Consecutive patients (2,764) with sporadic colorectal cancer from 1999 to 2005 were evaluated. The clinicopathological characteristics of these patients were reviewed. Univariate analysis was performed, and survival curves were constructed using the Kaplan-Meier method. Multivariate analysis assessed independent prognostic factors. Results The incidence of MA and SRC is 6% and 1.1%, respectively. MA and SRC tend to occur in patients aged ≤50 years (SRC 33%, MA 22%, ordinary adenocarcinomas (OA) 14%, p = 0.001) and are more commonly right-sided (MA 30%, SRC 27%, OA 19%, p = 0.001) than OA. SRC tend to be poorly differentiated (SRC 77%, MA 26%, OA 6%, p < 0.0001) and have a higher risk of recurrence (SRC 40%, MA 26%, OA 6%, p < 0.0001). SRC and MA are more likely to have locally advanced lesions (T3/T4; SRC 100%, MA 90%, OA 83%, p = 0.002) and lymph node metastases (SRC 89%, MA 61%, OA 52%, p < 0.0001) and present with an advanced stage at diagnosis (stage III/IV SRC 94%, MA 67%, OA 56%, p < 0.0001). SRC has poorer 5-year cancer-specific survival (CSS; 11.1%, 95% confidence interval (CI) 0-22.9%) compared with MA (46.8%, 95% CI 38.6-55.0%) and OA (58.7%, 95% CI 56.5-60.9%, p < 0.001). In a multivariate analysis, SRC is an independent poor prognostic factor (HR 1.9, 95% CI 1.1-3.0) but MA is not. Conclusion SRC and MA demonstrate clinicopathologic characteristics suggestive of a different biology compared with OA. In our dataset, SRC has a significantly poorer CSS whereas survival rates for MA are similar to OA. These characteristics are similar in both Asian and Western studies reported. Asian reports however suggest a lower incidence of MA.
Inflammatory bowel disease (IBD) was previously thought to be rare in Asia, but emerging data indicate rising incidence and prevalence of IBD in the region. The Asia Pacific Working Group on ...Inflammatory Bowel Disease was established in Cebu, Philippines, at the Asia Pacific Digestive Week conference in 2006 under the auspices of the Asian Pacific Association of Gastroenterology with the goal of developing best management practices, coordinating research, and raising awareness of IBD in the region. The consensus group previously published recommendations for the diagnosis and management of ulcerative colitis with specific relevance to the Asia‐Pacific region. The present consensus statements were developed following a similar process to address the epidemiology, diagnosis, and management of Crohn's disease. The goals of these statements are to pool the pertinent literature specifically highlighting relevant data and conditions in the Asia‐Pacific region relating to the economy, health systems, background infectious diseases, differential diagnoses, and treatment availability. It does not intend to be all comprehensive and future revisions are likely to be required in this ever‐changing field.
•A GC/TOFMS method was developed and validated for the metabotyping of human feces.•Feces demonstrated a more comprehensive metabolic coverage than fecal water.•Occult blood in stool exerted a ...negligible effect on the fecal metabotype.
Gas chromatography mass spectrometry (GC/MS)-based fecal metabonomics represents a powerful systems biology approach for elucidating metabolic biomarkers of lower gastrointestinal tract (GIT) diseases. Unlike metabolic profiling of fecal water, the profiling of complete fecal material remains under-explored. Here, a gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) method was developed and validated for the global metabonomic profiling of human feces. Fecal and fecal water metabotypes were also profiled and compared. Additionally, the unclear influence of blood in stool on the fecal metabotype was investigated unprecedentedly. Eighty milligram of lyophilized feces was ultrasonicated with 1mL of methanol:water (8:2) for 30min, followed by centrifugation, drying of supernatant, oximation and trimethylsilylation for 45min. Lyophilized feces demonstrated a more comprehensive metabolic coverage than fecal water, based on the number of chromatographic peaks. Principal component analysis (PCA) indicated occult blood (1mgHb/g feces) exerted a negligible effect on the fecal metabotype. Conversely, a unique metabotype related to feces spiked with gross blood (100mgHb/g feces) was revealed (PCA, R2X=0.837, Q2=0.794), confirming the potential confounding effect of gross GIT bleeding on the fecal metabotype. This pertinent finding highlights the importance of prudent interpretation of fecal metabonomic data, particularly in GIT diseases where bleeding is prevalent.
There is increasing preclinical evidence suggesting that metformin, an antidiabetic drug, has anticancer properties against various malignancies, including colorectal cancer. However, the majority of ...evidence, which was derived from cancer cell lines and xenografts, was likely to overestimate the benefit of metformin because these models are inadequate and require supraphysiologic levels of metformin. Here, we generated patient-derived xenograft (PDX) lines from 2 colorectal cancer patients to assess the properties of metformin and 5-fluorouracil (5-FU), the first-line drug treatment for colorectal cancer. Metformin (150 mg/kg) as a single agent inhibits the growth of both PDX tumors by at least 50% (
< 0.05) when administered orally for 24 days. In one of the PDX models, metformin given concurrently with 5-FU (25 mg/kg) leads to an 85% (
= 0.054) growth inhibition.
culture of organoids generated from PDX demonstrates that metformin inhibits growth by executing metabolic changes to decrease oxygen consumption and activating AMPK-mediated pathways. In addition, we also performed genetic characterizations of serial PDX samples with corresponding parental tissues from patients using next-generation sequencing (NGS). Our pilot NGS study demonstrates that PDX represents a useful platform for analysis in cancer research because it demonstrates high fidelity with parental tumor. Furthermore, NGS analysis of PDX may be useful to determine genetic identifiers of drug response. This is the first preclinical study using PDX and PDX-derived organoids to investigate the efficacy of metformin in colorectal cancer.
.
Background
The incidence of mismatch repair deficiency in colorectal cancer (CRC) in young people remains unknown in Asians. The present study assessed the clinicopathological features and efficacy ...of immunohistochemistry screening for Lynch syndrome in young Asian CRC patients.
Material and methods
This was a retrospective review conducted in Singapore General Hospital between January 2006 and December 2010 of 240 unrelated patients under the age of 50. All patients had immunohistochemical (IHC) staining for mismatch repair proteins in resected CRC specimen data retrieved from a prospective computerized database.
Results
A total of 21 % (
n
= 51) of the patients had abnormal IHC staining. Loss of staining for MLH1, MSH2, MSH6, and PMS2 proteins was observed in 10, 4, 6, and 13 % of tumors, respectively. Of the 22 patients who had abnormal staining of MLH1, 13 had concomitant abnormal staining for PMS2. One tumor specimen had abnormal staining in all four proteins. If the Amsterdam criteria alone were to be used, 86 % (
n
= 44) of the cohort would have not been detected for mismatch repair gene defects.
Conclusions
The overall burden of germline mismatch repair deficiency in the Singapore population may be as high as 21 %. The Amsterdam criteria alone are inadequate to detect Lynch syndrome patients. The use of IHC staining of at least four mismatch repair proteins is a useful screening strategy for Lynch syndrome diagnosis. Routine screening of mismatch repair deficiency may be recommended for all young Asian CRC patients.
PDF
