Nutritional risk is a clinical predictor of postoperative mortality and morbidity in surgery for colorectal cancer

This study investigated whether nutritional risk scores applied at hospital admission predict mortality and complications after colorectal cancer surgery.

CXC receptor-4 mRNA silencing abrogates CXCL12-induced migration of colorectal cancer cells

Background Interactions between CXCR4 and its ligand CXCL12 have been shown to be involved in cancer progression in colorectal cancer (CRC). We performed a comparative CXCL12/CXCR4 expression analysis and assessed the effect of external CXCL12 stimulation on migration of CRC cells without and with CXCR4 inhibition. Methods Expression of CXCL12/CXCR4 was assessed by quantitative real-time PCR, ELISA and immunohistochemistry in resection specimens of 50 CRC patients as well as in the corresponding normal tissues and in three human CRC cell lines with different metastatic potential (Caco-2, SW480 and HT-29). Migration assays were performed after stimulation with CXCL12 and CXCR4 was inhibited by siRNA and neutralizing antibodies. Results In CRC tissues CXCL12 was significantly down-regulated and CXCR4 was significantly up-regulated compared to the corresponding normal tissues. In cell lines CXCR4 was predominantly expressed in SW480 and less pronounced in HT-29 cells. CXCL12 was only detectable in Caco-2 cells. CXCL12 stimulation had no impact on Caco-2 cells but significantly increased migration of CXCR4 bearing SW480 and HT-29 cells. This effect was significantly abrogated by neutralizing anti-CXCR4 antibody as well as by CXCR4 siRNAs (P < 0.05). Conclusions CXCR4 expression was up-regulated in CRC and CXCL12 stimulation increased migration in CXCR4 bearing cell lines. Migration was inhibited by both neutralizing CXCR4 antibodies and CXCR4 siRNAs. Thus, the expression and functionality of CXCR4 might be associated with the metastatic potential of CRC cells and CXCL12/CXCR4 interactions might therefore constitute a promising target for specific treatment interventions.

Intratumoral budding as a potential parameter of tumor progression in mismatch repair-proficient and mismatch repair-deficient colorectal cancer patients

In colorectal cancer, tumor budding at the invasive front (peritumoral budding) is an established prognostic parameter and decreased in mismatch repair-deficient tumors. In contrast, the clinical relevance of tumor budding within the tumor center (intratumoral budding) is not yet known. The aim of the study was to determine the correlation of intratumoral budding with peritumoral budding and mismatch repair status and the prognostic impact of intratumoral budding using 2 independent patient cohorts. Following pancytokeratin staining of whole-tissue sections and multiple-punch tissue microarrays, 2 independent cohorts (group 1: n = 289; group 2: n = 222) with known mismatch repair status were investigated for intratumoral budding and peritumoral budding. In group 1, intratumoral budding was strongly correlated to peritumoral budding (r = 0.64; P < .001) and less frequent in mismatch repair-deficient versus mismatch repair-proficient cases (P = .177). Sensitivity and specificity for lymph node positivity were 72.7% and 72.1%. In mismatch repair-proficient cancers, high-grade intratumoral budding was associated with right-sided location (P = .024), advanced T stage (P = .001) and N stage pN (P < .001), vascular invasion (P = .041), infiltrating tumor margin (P = .003), and shorter survival time (P = .014). In mismatch repair-deficient cancers, high intratumoral budding was linked to higher tumor grade (P = .004), vascular invasion (P = .009), infiltrating tumor margin (P = .005), and more unfavorable survival time (P = .09). These associations were confirmed in group 2. High-grade intratumoral budding was a poor prognostic factor in univariate (P < .001) and multivariable analyses (P = .019) adjusting for T stage, N stage distant metastasis, and adjuvant therapy. These preliminary results on 511 patients show that intratumoral budding is an independent prognostic factor, supporting the future investigation of intratumoral budding in larger series of both preoperative and postoperative rectal and colon cancer specimens.

Thiazolide-induced apoptosis in colorectal cancer cells is mediated via the Jun kinase-Bim axis and reveals glutathione-S-transferase P1 as Achilles' heel

Glutathione-S-transferase of the Pi class (GSTP1) is frequently overexpressed in a variety of solid tumors and has been identified as a potential therapeutic target for cancer therapy. GSTP1 is a phase II detoxification enzyme and conjugates the tripeptide glutathione to endogenous metabolites and xenobiotics, thereby limiting the efficacy of antitumor chemotherapeutic treatments. In addition, GSTP1 regulates cellular stress responses and apoptosis by sequestering and inactivating c-Jun N-terminal kinase (JNK). Thiazolides are a novel class of antibiotics for the treatment of intestinal pathogens with no apparent side effects on the host cells and tissue. Here we show that thiazolides induce a GSTP1-dependent and glutathione-enhanced cell death in colorectal tumor cell lines. Downregulation of GSTP1 reduced the apoptotic activity of thiazolides, whereas overexpression enhanced it. Thiazolide treatment caused strong Jun kinase activation and Jun kinase-dependent apoptosis. As a critical downstream target of Jun kinase we identified the pro-apoptotic Bcl-2 homolog Bim. Thiazolides induced Bim expression and activation in a JNK-dependent manner. Downregulation of Bim in turn significantly blocked thiazolide-induced apoptosis. Whereas low concentrations of thiazolides failed to induce apoptosis directly, they potently sensitized colon cancer cells to TNF-related apoptosis-inducing ligand- and chemotherapeutic drug-induced cell death. Although GSTP1 overexpression generally limits chemotherapy and thus antitumor treatment, our study identifies GSTP1 as Achilles' heel and thiazolides as novel interesting apoptosis sensitizer for the treatment of colorectal tumors.

Enhanced activity of meprin-?, a pro-migratory and pro-angiogenic protease, in colorectal cancer

Meprin-α is a metalloprotease overexpressed in cancer cells, leading to the accumulation of this protease in a subset of colorectal tumors. The impact of increased meprin-α levels on tumor progression is not known. We investigated the effect of this protease on cell migration and angiogenesis in vitro and studied the expression of meprin-α mRNA, protein and proteolytic activity in primary tumors at progressive stages and in liver metastases of patients with colorectal cancer, as well as inhibitory activity towards meprin-α in sera of cancer patient as compared to healthy controls. We found that the hepatocyte growth factor (HGF)-induced migratory response of meprin-transfected epithelial cells was increased compared to wild-type cells in the presence of plasminogen, and that the angiogenic response in organ-cultured rat aortic explants was enhanced in the presence of exogenous human meprin-α. In patients, meprin-α mRNA was expressed in colonic adenomas, primary tumors UICC (International Union Against Cancer) stage I, II, III and IV, as well as in liver metastases. In contrast, the corresponding protein accumulated only in primary tumors and liver metastases, but not in adenomas. However, liver metastases lacked meprin-α activity despite increased expression of the corresponding protein, which correlated with inefficient zymogen activation. Sera from cancer patients exhibited reduced meprin-α inhibition compared to healthy controls. In conclusion, meprin-α activity is regulated differently in primary tumors and metastases, leading to high proteolytic activity in primary tumors and low activity in liver metastases. By virtue of its pro-migratory and pro-angiogenic activity, meprin-α may promote tumor progression in colorectal cancer.

Impact of CD39 and purinergic signalling on the growth and metastasis of colorectal cancer

Despite improvements in prevention and management of colorectal cancer (CRC), uncontrolled tumor growth with metastatic spread to distant organs remains an important clinical concern. Genetic deletion of CD39, the dominant vascular and immune cell ectonucleotidase, has been shown to delay tumor growth and blunt angiogenesis in mouse models of melanoma, lung and colonic malignancy. Here, we tested the influence of CD39 on CRC tumor progression and metastasis by investigating orthotopic transplanted and metastatic cancer models in wild-type BALB/c, human CD39 transgenic and CD39 deficient mice. We also investigated CD39 and P2 receptor expression patterns in human CRC biopsies. Murine CD39 was expressed by endothelium, stromal and mononuclear cells infiltrating the experimental MC-26 tumors. In the primary CRC model, volumes of tumors in the subserosa of the colon and/or rectum did not differ amongst the treatment groups at day 10, albeit these tumors rarely metastasized to the liver. In the dissemination model, MC-26 cell line-derived hepatic metastases grew significantly faster in CD39 over-expressing transgenics, when compared to CD39 deficient mice. Murine P2Y2 was significantly elevated at both mRNA and protein levels, within the larger liver metastases obtained from CD39 transgenic mice where changes in P2X7 levels were also noted. In clinical samples, lower levels of CD39 mRNA in malignant CRC tissues appeared associated with longer duration of survival and could be linked to less invasive tumors. The modulatory effects of CD39 on tumor dissemination and differential levels of CD39, P2Y2 and P2X7 expression in tumors suggest involvement of purinergic signalling in these processes. Our studies also suggest potential roles for purinergic-based therapies in clinical CRC.

miR-21 functionally interacts with the 3'UTR of chemokine CCL20 and down-regulates CCL20 expression in miR-21 transfected colorectal cancer cells

As deregulation of miRNAs and chemokine CCL20 was shown to play a role in colorectal cancer (CRC) pathogenesis, we analyzed the functional interactions of candidate miRNAs with CCL20 mRNA. After target prediction software programs indicated a role for miR-21 in CCL20 regulation, we applied the luciferase reporter assay system to demonstrate that miR-21 functionally interacts with the 3'UTR of CCL20 mRNA and down-regulates CCL20 in miR-21 mimic transfected CRC cell lines (Caco-2, SW480 and SW620). Thus, regulation of CCL20 expression by miR-21 might be a regulatory mechanism involved in progression of CRC.

Serum amino acid profiles and their alterations in colorectal cancer

Mass spectrometry-based serum metabolic profiling is a promising tool to analyse complex cancer associated metabolic alterations, which may broaden our pathophysiological understanding of the disease and may function as a source of new cancer-associated biomarkers. Highly standardized serum samples of patients suffering from colon cancer (n = 59) and controls (n = 58) were collected at the University Hospital Leipzig. We based our investigations on amino acid screening profiles using electrospray tandem-mass spectrometry. Metabolic profiles were evaluated using the Analyst 1.4.2 software. General, comparative and equivalence statistics were performed by R 2.12.2. 11 out of 26 serum amino acid concentrations were significantly different between colorectal cancer patients and healthy controls. We found a model including CEA, glycine, and tyrosine as best discriminating and superior to CEA alone with an AUROC of 0.878 (95% CI 0.815-0.941). Our serum metabolic profiling in colon cancer revealed multiple significant disease-associated alterations in the amino acid profile with promising diagnostic power. Further large-scale studies are necessary to elucidate the potential of our model also to discriminate between cancer and potential differential diagnoses. In conclusion, serum glycine and tyrosine in combination with CEA are superior to CEA for the discrimination between colorectal cancer patients and controls.

Tumor budding score based on 10 high-power fields is a promising basis for a standardized prognostic scoring system in stage II colorectal cancer

Tumor budding is recognized by the World Health Organization as an additional prognostic factor in colorectal cancer but remains unreported in diagnostic work due to the absence of a standardized scoring method. This study aims to assess the most prognostic and reproducible scoring systems for tumor budding in colorectal cancer. Tumor budding on pancytokeratin-stained whole tissue sections from 105 well-characterized stage II patients was scored by 3 observers using 7 methods: Hase, Nakamura, Ueno, Wang (conventional and rapid method), densest high-power field, and 10 densest high-power fields. The predictive value for clinicopathologic features, the prognostic significance, and interobserver variability of each scoring method was analyzed. Pancytokeratin staining allowed accurate evaluation of tumor buds. Interobserver agreement for 3 observers was excellent for densest high-power field (intraclass correlation coefficient, 0.83) and 10 densest high-power fields (intraclass correlation coefficient, 0.91). Agreement was moderate to substantial for the conventional Wang method (κ = 0.46-0.62) and moderate for the rapid method (κ = 0.46-0.58). For Nakamura, moderate agreement (κ = 0.41-0.52) was reached, whereas concordance was fair to moderate for Ueno (κ = 0.39-0.56) and Hase (κ = 0.29-0.51). The Hase, Ueno, densest high-power field, and 10 densest high-power field methods identified a significant association of tumor budding with tumor border configuration. In multivariate analysis, only tumor budding as evaluated in densest high-power field and 10 densest high-power fields had significant prognostic effects on patient survival (P < .01), with high prognostic accuracy over the full 10-year follow-up. Scoring tumor buds in 10 densest high-power fields is a promising method to identify stage II patients at high risk for recurrence in daily diagnostics; it is highly reproducible, accounts for heterogeneity, and has a strong predictive value for adverse outcome.

Proposal for a 10-high-power-fields scoring method for the assessment of tumor budding in colorectal cancer

Although tumor budding is linked to adverse prognosis in colorectal cancer, it remains largely unreported in daily diagnostic work due to the absence of a standardized scoring method. Our aim was to assess the inter-observer agreement of a novel 10-high-power-fields method for assessment of tumor budding at the invasive front and to confirm the prognostic value of tumor budding in our setting of colorectal cancers. Whole tissue sections of 215 colorectal cancers with full clinico-pathological and follow-up information were stained with cytokeratin AE1/AE3 antibody. Presence of buds was scored across 10-high-power fields at the invasive front by two pathologists and two additional observers were asked to score 50 cases of tumor budding randomly selected from the larger cohort. The measurements were correlated to the patient and tumor characteristics. Inter-observer agreement and correlation between observers' scores were excellent (P<0.0001; intraclass correlation coefficient=0.96). A test subgroup of 65 patients (30%) was used to define a valid cutoff score for high-grade tumor budding and the remaining 70% of the patients were entered into the analysis. High-grade budding was defined as an average of ≥10 buds across 10-high-power fields. High-grade budding was associated with a higher tumor grade (P<0.0001), higher TNM stage (P=0.0003), vascular invasion (P<0.0001), infiltrating tumor border configuration (P<0.0001) and reduced survival (P<0.0001). Multivariate analysis confirmed its independent prognostic effect (P=0.007) when adjusting for TNM stage and adjuvant therapy. Using 10-high-power fields for evaluating tumor budding has independent prognostic value and shows excellent inter-observer agreement. Like the BRE and Gleason scores in breast and prostate cancers, respectively, tumor budding could be a basis for a prognostic score in colorectal cancer.

Tumour budding: a promising parameter in colorectal cancer

In 2011, the Tumour Node Metastasis (TNM) staging system still remains the gold standard for stratifying colorectal cancer (CRC) patients into prognostic subgroups, and is considered a solid basis for treatment management. Nevertheless, there is still a challenge with regard to therapeutic strategy; stage II patients are not typically selected for postoperative adjuvant chemotherapy, although some stage II patients have a comparable outcome to stage III patients who, themselves do receive such treatment. Consequently, there has been an inundation of 'prognostic biomarker' studies aiming to improve the prognostic stratification power of the TNM staging system. Most proposed biomarkers are not implemented because of lack of reproducibility, validation and standardisation. This problem can be partially resolved by following the REMARK guidelines. In search of novel prognostic factors for patients with CRC, one might glance at a table in the book entitled 'Prognostic Factors in Cancer' published by the International Union against Cancer (UICC) in 2006, in which TNM stage, L and V classifications are considered 'essential' prognostic factors, whereas tumour grade, perineural invasion, tumour budding and tumour-border configuration among others are proposed as 'additional' prognostic factors. Histopathology reports normally include the 'essential' features and are accompanied by tumour grade, histological subtype and information on perineural invasion, but interestingly, the tumour-border configuration (i.e., growth pattern) and especially tumour budding are rarely reported. Although scoring systems such as the 'BRE' in breast and 'Gleason' in prostate cancer are solidly based on histomorphological features and used in daily practice, no such additional scoring system to complement TNM staging is available for CRC. Regardless of differences in study design and methods for tumour-budding assessment, the prognostic power of tumour budding has been confirmed by dozens of study groups worldwide, suggesting that tumour budding may be a valuable candidate for inclusion into a future prognostic scoring system for CRC. This mini-review therefore attempts to present a short and concise overview on tumour budding, including morphological, molecular and prognostic aspects underlining its inter-disciplinary relevance.

Characterization of CDKN2A(p16) methylation and impact in colorectal cancer: systematic analysis using pyrosequencing

Background The aim of this study is to analyse CDKN2A methylation using pyrosequencing on a large cohort of colorectal cancers and corresponding non-neoplastic tissues. In a second step, the effect of methylation on clinical outcome is addressed. Methods Primary colorectal cancers and matched non-neoplastic tissues from 432 patients underwent CDKN2A methylation analysis by pyrosequencing (PyroMarkQ96). Methylation was then related to clinical outcome, microsatellite instability (MSI), and BRAF and KRAS mutation. Different amplification conditions (35 to 50 PCR cycles) using a range of 0-100% methylated DNA were tested. Results Background methylation was at most 10% with ≥35 PCR cycles. Correlation of observed and expected values was high, even at low methylation levels (0.02%, 0.6%, 2%). Accuracy of detection was optimal with 45 PCR cycles. Methylation in normal mucosa ranged from 0 to >90% in some cases. Based on the maximum value of 10% background, positivity was defined as a ≥20% difference in methylation between tumor and normal tissue, which occurred in 87 cases. CDKN2A methylation positivity was associated with MSI (p = 0.025), BRAF mutation (p < 0.0001), higher tumor grade (p < 0.0001), mucinous histology (p = 0.0209) but not with KRAS mutation. CDKN2A methylation had an independent adverse effect (p = 0.0058) on prognosis. Conclusion The non-negligible CDKN2A methylation of normal colorectal mucosa may confound the assessment of tumor-specific hypermethylation, suggesting that corresponding non-neoplastic tissue should be used as a control. CDKN2A methylation is robustly detected by pyrosequencing, even at low levels, suggesting that this unfavorable prognostic biomarker warrants investigation in prospective studies.

The impact of CpG island methylator phenotype and microsatellite instability on tumour budding in colorectal cancer

In colorectal cancer, tumour budding, a process likened to epithelial mesenchymal transition, is an adverse prognostic factor which is rarely found in tumours with high-level microsatellite instability (MSI-H). Cases with MSI-H or high-level CpG island methylator phenotype (CIMP-H) have similar histomorphological features, yet seemingly opposite prognosis. We hypothesized that tumour budding is related to CIMP, thus partially explaining this prognostic difference.

Diagnostic reproducibility of tumour budding in colorectal cancer: a multicentre, multinational study using virtual microscopy

Puppa G, Senore C, Sheahan K, Vieth M, Lugli A, Zlobec I, Pecori S, Wang L M, Langner C, Mitomi H, Nakamura T, Watanabe M, Ueno H, Chasle J, Conley S A, Herlin P, Lauwers G Y & Risio M (2012) Histopathology Diagnostic reproducibility of tumour budding in colorectal cancer: a multicentre, multinational study using virtual microscopy Aims:  Despite the established prognostic relevance of tumour budding in colorectal cancer, the reproducibility of the methods reported for its assessment has not yet been determined, limiting its use and reporting in routine pathology practice. Methods and results:  A morphometric system within telepathology was devised to evaluate the reproducibility of the various methods published for the assessment of tumour budding in colorectal cancer. Five methods were selected to evaluate the diagnostic reproducibility among 10 investigators, using haematoxylin and eosin (H&E) and AE1-3 cytokeratin-immunostained, whole-slide digital scans from 50 pT1-pT4 colorectal cancers. The overall interobserver agreement was fair for all methods, and increased to moderate for pT1 cancers. The intraobserver agreement was also fair for all methods and moderate for pT1 cancers. Agreement was dependent on the participants' experience with tumour budding reporting and performance time. Cytokeratin immunohistochemistry detected a higher percentage of tumour budding-positive cases with all methods compared to H&E-stained slides, but did not influence agreement levels. Conclusions:  An overall fair level of diagnostic agreement for tumour budding in colorectal cancer was demonstrated, which was significantly higher in early cancer and among experienced gastrointestinal pathologists. Cytokeratin immunostaining facilitated detection of budding cancer cells, but did not result in improved interobserver agreement.