Etiology-independent activation of the LTß-LTßR-RELB axis drives aggressiveness and predicts poor prognosis in HCC.

BACKGROUND AND AIMS: HCC is the most common primary liver tumor, with an increasing incidence worldwide. HCC is a heterogeneous malignancy and usually develops in a chronically injured liver. The NF-κB signaling network consists of a canonical and a noncanonical branch. Activation of canonical NF-κB in HCC is documented. However, a functional and clinically relevant role of noncanonical NF-κB and its downstream effectors is not established. APPROACH AND RESULTS: Four human HCC cohorts (total n = 1462) and 4 mouse HCC models were assessed for expression and localization of NF-κB signaling components and activating ligands. In vitro , NF-κB signaling, proliferation, and cell death were measured, proving a pro-proliferative role of v-rel avian reticuloendotheliosis viral oncogene homolog B (RELB) activated by means of NF-κB-inducing kinase. In vivo , lymphotoxin beta was identified as the predominant inducer of RELB activation. Importantly, hepatocyte-specific RELB knockout in a murine HCC model led to a lower incidence compared to controls and lower maximal tumor diameters. In silico , RELB activity and RELB-directed transcriptomics were validated on the The Cancer Genome Atlas HCC cohort using inferred protein activity and Gene Set Enrichment Analysis. In RELB-active HCC, pathways mediating proliferation were significantly activated. In contrast to v-rel avian reticuloendotheliosis viral oncogene homolog A, nuclear enrichment of noncanonical RELB expression identified patients with a poor prognosis in an etiology-independent manner. Moreover, RELB activation was associated with malignant features metastasis and recurrence. CONCLUSIONS: This study demonstrates a prognostically relevant, etiology-independent, and cross-species consistent activation of a lymphotoxin beta/LTßR/RELB axis in hepatocarcinogenesis. These observations may harbor broad implications for HCC, including possible clinical exploitation.

Olfactomedin 4 associates with expression of differentiation markers but not with properties of cancer stemness, EMT nor metastatic spread in colorectal cancer.

Tumor stem cells play a pivotal role in carcinogenesis and metastatic spread in colorectal cancer (CRC). Olfactomedin 4 (OLFM4) is co-expressed with the established stem cell marker leucine-rich repeat-containing G protein-coupled receptor 5 at the bottom of intestinal crypts and has been suggested as a surrogate for cancer stemness and a biomarker in gastrointestinal tumors associated with prognosis. Therefore, it was the aim of the present study to clarify whether OLFM4 is involved in carcinogenesis and metastatic spread in CRC. We used a combined approach of functional assays using forced OLFM4 overexpression in human CRC cell lines, xenograft mice, and an immunohistochemical approach using patient tissues to investigate the impact of OLFM4 on stemness, canonical Wnt signaling, properties of metastasis and differentiation as well as prognosis. OLFM4 expression correlated weakly with tumor grade in one patient cohort (metastasis collection: p = 0.05; pooled analysis of metastasis collection and survival collection: p = 0.19) and paralleled the expression of differentiation markers (FABP2, MUC2, and CK20) (p = 0.002) but did not correlate with stemness-associated markers. Further analyses in CRC cells lines as well as xenograft mice including forced overexpression of OLFM4 revealed that OLFM4 neither altered the expression of markers of stemness nor epithelial-mesenchymal transition, nor did OLFM4 itself drive proliferation, migration, or colony formation, which are all prerequisites of carcinogenesis and tumor progression. In line with this, we found no significant correlation between OLFM4 expression, metastasis, and patient survival. In summary, expression of OLFM4 in human CRC seems to be characteristic of differentiation marker expression in CRC but is not a driver of carcinogenesis nor metastatic spread.

p70 Ribosomal Protein S6 Kinase Is a Checkpoint of Human Hepatic Stellate Cell Activation and Liver Fibrosis in Mice.

BACKGROUND & AIMS: Progression of chronic liver disease (CLD) to liver cirrhosis and liver cancer is a major global cause of morbidity and mortality. Treatment options capable of inhibiting progression of liver fibrosis when etiological treatment of CLD is not available or fails have yet to be established. We investigated the role of serine/threonine kinase p70 ribosomal protein S6 kinase (p70S6K) as checkpoint of fibrogenesis in hepatic stellate cells (HSCs) and as target for the treatment of liver fibrosis. APPROACH & RESULTS: Immunohistochemistry was used to assess p70S6K expression in liver resection specimen. Primary human or murine HSCs from wild-type or p70S6K-/- mice as well as LX-2 cells were used for in vitro experiments. Specific small interfering RNA or CEP-1347 were used to silence or inhibit p70S6K and assess its functional relevance in viability, contraction and migration assays, fluorescence-activated cell sorting, and Western blot. These results were validated in vivo by a chemical model of fibrogenesis using wild-type and p70S6K-/- mice. Expression of p70S6K was significantly increased in human cirrhotic vs noncirrhotic liver-tissue and progressively increased in vitro through activation of primary human HSCs. Conversely, p70S6K induced fibrogenic activation of HSCs in different models, including the small interfering RNA-based silencing of p70S6K in HSC lines, experiments with p70S6K-/- cells, and the pharmacological inhibition of p70S6K by CEP-1347. These findings were validated in vivo as p70S6K-/- mice developed significantly less fibrosis upon exposure to CCl4. CONCLUSIONS: We establish p70S6K as a checkpoint of fibrogenesis in vitro and in vivo and CEP-1347 as potential treatment option that can safely be used for long-term treatment.

Clinical Evidence on the Interaction Between MLK4, KRAS and Microsatellite Instability to Determine the Prognosis of Early-Stage Colorectal Carcinoma.

BACKGROUND/AIMS: MLK4 (KIAA1804) is the second most frequently mutated kinase in microsatellite stable (MSS) colorectal carcinomas (CRC). This molecule is known to regulate different physiological cellular processes, including cell cycle, senescence and apoptosis, and mechanistic evidence has been provided that MLK4 plays a role in carcinogenesis. However, whether this kinase exerts a tumor suppressive role or an oncogenic function is still an object of debate. This study aims to elucidate the role of MLK4 in the pathogenesis of CRC by investigating human tumor specimens. METHODS: This study assessed MLK4 expression levels by immunohistochemistry in surgical tumor samples from 204 early-stage CRC patients and their correlation with various clinical-pathological features and patients' outcomes. In addition, MLK4 mRNA transcription was analysed in an independent cohort of 786 colon cancer samples. RESULTS: Loss of MLK4 staining was associated with poor overall (OS) and progression free survival (PFS) in CRC patients during a univariate analysis (OS:101 vs 164 months, p=0.0002; PFS:85 vs 125 months, p=0.0001), as well as in multivariate analysis (OS:HR=1.70; p=0.001; PFS:HR=1,61; p=0.001). This was confirmed by analysis of MLK4 mRNA in the second independent cohort. A subgroup analysis according to KRAS mutation status showed that MLK4 staining was associated with better OS and PFS in KRAS mutated cases (HR=2.77; p=0.0001 and HR=2.31; p=0.0003, respectively) and microsatellite stable tumors (HR=1.87; p=0.002 and HR=1.06; p=0.006) but not in KRAS wildtype and microsatellite unstable tumors. CONCLUSION: By providing the first report from clinical specimens on the prognostic significance of MLK4, we define an oncogenic loss-of-function of this kinase and suggest a possible role in the interaction with KRAS signaling in determining an aggressive phenotype of CRC. These findings warrant the further investigation of MLK4 in wider cohorts and various clinical settings.

RBP7 is a clinically prognostic biomarker and linked to tumor invasion and EMT in colon cancer.

RBP7 is a member of the cellular retinol-binding protein (CRBP) family and previous data suggested a link between CRBPs and the malignant transformation of colon cancer cells. Here, we investigated the potential of RBP7 as a predictive biomarker for patients with colon cancer and determined its functional relevance for tumor progression. We analyzed RBP7 protein and mRNA expression in independent tissue collections of colon cancers with recorded follow-up data, including data from TCGA. We used gene set enrichment analyses to characterize its functional role. Effects of RBP7 on migration and invasion were determined in transwell assays. High expression of RBP7 was an independent biomarker of poor cancer specific survival in early and late stage colon cancer, and linked to colon cancer progression. Gene set enrichment analysis revealed a strong association of RBP7, colon cancer invasion and epithelial mesenchymal transition (EMT). Ectopic expression of RBP7 increased migration and invasion of colon cancer cells. Our findings demonstrate that RBP7 is a strong prognostic biomarker in colon cancer that functionally contributes to the malignant phenotype of colon cancer cells. This may aid in risk stratification for the therapeutic management of patients with colorectal cancer.

Targeting c-MYC through Interference with NAMPT and SIRT1 and Their Association to Oncogenic Drivers in Murine Serrated Intestinal Tumorigenesis.

We recently described a positive feedback loop connecting c-MYC, NAMPT, DBC1 and SIRT1 that contributes to unrestricted cancer cell proliferation. Here we determine the relevance of the loop for serrated route intestinal tumorigenesis using genetically well-defined BrafV600E and K-rasG12D mouse models. In both models we show that c-MYC and SIRT1 protein expression increased through progression from hyperplasia to invasive carcinomas and metastases. It correlated with high NAMPT expression and was directly associated to activation of the oncogenic drivers. Assessing functional and molecular consequences of pharmacological interference with factors of the loop, we found that inhibition of NAMPT resulted in apoptosis and reduced clonogenic growth in human BRAF-mutant colorectal cancer cell lines and patient-derived tumoroids. Blocking SIRT1 activity was only effective when combined with a PI3K inhibitor, whereas the latter antagonized the effects of NAMPT inhibition. Interfering with the positive feedback loop was associated with down-regulation of c-MYC and temporary de-repression of TP53, explaining the anti-proliferative and pro-apoptotic effects. In conclusion we show that the c-MYC-NAMPT-DBC1-SIRT1 positive feedback loop contributes to murine serrated tumor progression. Targeting the feedback loop exerted a unique, dual therapeutic effect of oncoprotein inhibition and tumor suppressor activation. It may therefore represent a promissing target for serrated colorectal cancer, and presumably for other cancer types with deregulated c-MYC.

Expression of n-MYC, NAMPT and SIRT1 in Basal Cell Carcinomas and their Cells of Origin.

Deregulated Hedgehog signalling is a driver of basal cell carcinomas. One effector of the Hedgehog pathway is n-MYC. c/n-MYC proteins, NAMPT and DBC1 are linked to SIRT1 in a positive feedback loop that may contribute to tumorigenesis of basal cell carcinoma. In 5 basal cell carcinoma types immunohistochemistry revealed n-MYC, NAMPT and SIRT1 expression. DBC1 was homogenously expressed in all epithelial cells. NAMPT, SIRT1 and c-MYC were expressed in the stratum basale of human and murine skin. In hair follicles NAMPT and SIRT1 were expressed together with c-MYC and n-MYC, except for the matrix, where n-MYC was strongly positive, but c-MYC expression was absent. Therefore, a common pathway connecting n-MYC, NAMPT and SIRT1 may be active in basal cell carcinomas and in their cells of origin. This pathway may contribute to the development of basal cell carcinomas. Targeting factors in the feedback loop may offer novel therapeutic options.

The c-MYC/NAMPT/SIRT1 feedback loop is activated in early classical and serrated route colorectal cancer and represents a therapeutic target.

We have recently identified a positive feedback loop in which c-MYC increases silent information regulator 1 (SIRT1) protein level and activity through transcriptional activation of nicotinamide phosphoribosyltransferase (NAMPT) and NAD+ increase. Here, we determined the relevance of the c-MYC-NAMPT-SIRT1 feedback loop, including the SIRT1 inhibitor deleted in breast cancer 1 (DBC1), for the development of conventional and serrated colorectal adenomas. Immunohistochemical analyses of 104 conventional adenomas with low- and high-grade dysplasia and of 157 serrated lesions revealed that elevated expression of c-MYC, NAMPT, and SIRT1 characterized all conventional and serrated adenomas, whereas DBC1 was not differentially regulated. Analyzing publicly available pharmacogenomic databases from 43 colorectal cancer cell lines demonstrated that responsiveness towards a NAMPT inhibitor was significantly associated with alterations in PTEN and TGFBR2, while features such as BRAF or RNF43 alterations, or microsatellite instability typical for serrated route colorectal cancer, showed increased sensitivities for inhibition of NAMPT and SIRT1. Our findings suggest an activation of the c-MYC-NAMPT-SIRT1 feedback loop that may crucially contribute to initiation and development of both routes to colorectal cancer. Targeting of NAMPT or SIRT1 may represent novel therapeutic strategies with putative higher sensitivity of the serrated route colorectal cancer subtype.

Correlation Between Baseline Osteoprotegerin Serum Levels and Prognosis of Advanced-Stage Colorectal Cancer Patients.

BACKGROUND/AIMS: Osteoprotegerin (OPG) is a soluble receptor of the pro-apoptotic cytokine TRAIL which is thought to contribute to tumour development by inhibiting apoptosis or affecting other aspects of tumour biology, including cell proliferation and immune response. Although immunohistochemical studies suggest that OPG correlates with survival in metastatic colorectal cancer (mCRC), only scarce data are available on serum OPG in CRC patients. METHODS: In this pilot study, we assessed the prognostic significance of serum OPG and CEA (Carcinoembryonic antigen) in 81 patients with UICC (Union for International Cancer Control) stage-IV mCRC. OPG was additionally assessed by immunohistochemistry in primary tissue samples from 33 patients of the same cohort. RESULTS: Baseline serum OPG correlated with CEA (r=0.36, p=0.0011), but independently predicted survival of mCRC patients. Life expectancy was poorer in patients with OPG levels above the median concentration of 51ng/ml (median overall survival [95% confidence interval] 1.8 years [1.3-3.0] vs. 1.0 [0.7-1.2] p=0.013). Patients with high levels of both OPG and CEA had an even poorer life expectancy vs. low-OPG/low-CEA patients (0.9 years [0.6-1.5] vs. 3 years [1.2-4.4], p=0.015), indicating that CEA and OPG have additive prognostic significance. Immunohistochemical analysis of OPG failed to show a correlation between OPG staining and survival (p=0.055) or OPG concentration from matched serum samples. CONCLUSIONS: This pilot study provides evidence of independent prognostic significance of serum OPG in patients with advanced mCRC and warrants its further prospective validation.

Impact of reassessment of colonic hyperplastic polyps by expert GI pathologists.

BACKGROUND: Recommended follow-up intervals after endoscopic removal of hyperplastic polyps (HP) and sessile serrated adenomas (SSA) differ because of assumed differences in biological behaviour. However, histopathologic differentiation is difficult, with higher SSA rates reported from specialist GI histopathologists. OBJECTIVE: The objective of this study was to clarify the relevance of histologic reassessment of HP. DESIGN AND SETTING: From a prospective screening colonoscopy study relevant serrated lesions (excluding distal small HP ≤5 mm) diagnosed by private practice pathologists were reassessed by four specialized GI pathologists PATIENTS: One thousand sixty-nine screening colonoscopies were performed in patients. MAIN OUTCOME MEASUREMENTS: In terms of main outcome measurements, there is a likelihood of changes of the HP diagnosis on reassessment, as well as interrater variability. RESULTS: SSA were initially diagnosed in 7 cases (0.7%) and relevant HP in 83 (7.8%; 101 lesions). Of the latter, the chance of a change in diagnosis from HP to SSA by any of the four specialist histopathologists was higher for larger (>5 mm) and right-sided lesions (19.1 vs 1.3%, OR 18.4, p = 0.04) including a higher likelihood to change recommended follow-up intervals (32.1 vs 3.3%, p < 0.01). However, follow-up intervals were determined by concomitant adenomas in 41%. Interrater variability was also higher for these lesions (p = 0.04), with an overall kappa value of 0.48. However, this issue related to only 1.2% of the 1069 study cases. LIMITATION: The limitations this study are the limited case number as well as limited retrospective assessment. CONCLUSIONS: Right-sided HP >5 mm had a higher chance of change in diagnosis to SSA; therefore, they should probably be treated like adenomas and be removed. However, reliable data for recommendations on follow-up intervals of HP or SSA will require follow-up studies.

FDG-PET reveals improved cardiac regeneration and attenuated adverse remodelling following Sitagliptin + G-CSF therapy after acute myocardial infarction.

AIMS: Dual therapy comprising G-CSF for mobilization of bone marrow-derived progenitor cells (BMPCs), with simultaneous pharmacological inhibition of dipeptidylpeptidase-IV for enhanced myocardial recruitment of circulating BMPC via the SDF-1α/CXCR4-axis, has been shown to improve survival after acute myocardial infarction (AMI). Using an innovative method to provide non-invasive serial in vivo measurements and information on metabolic processes, we aimed to substantiate the possible effects of this therapeutic concept on cardiac remodelling after AMI using 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET). METHODS AND RESULTS: AMI was induced in C57BL/6 mice by performing surgical ligation of the left anterior descending artery in these mice. Animals were then treated with granulocyte-colony stimulating factor + Sitagliptin (GS) or placebo for a duration of 5 days following AMI. From serial PET scans, we verified that the infarct size in GS-treated mice (n = 13) was significantly reduced at Day 30 after AMI when compared with the mice receiving placebo (n = 10). Analyses showed a normalized FDG uptake on Day 6 in GS-treated mice, indicating an attenuation of the cardiac inflammatory response to AMI in treated animals. Furthermore, flow cytometry showed a significant increase in the anti-inflammatory M2-macrophages subpopulation in GS-treated animals. In comparing GS treated with placebo animals, those receiving GS-therapy showed a reduction in myocardial hypertrophy and left ventricular dilatation, which indicates the beneficial effect of GS treatment on cardiac remodelling. Remarkably, flow cytometry and immunohistochemistry showed an increase of myocardial c-kit positive cells in treated mice (n = 12 in both groups). CONCLUSION: Using the innovative method of micro-PET for non-invasive serial in vivo measurements of metabolic myocardial processes in mice, we were able to provide mechanistic evidence that GS therapy improves cardiac regeneration and reduces adverse remodelling after AMI.

ITF-2B protein levels are correlated with favorable prognosis in patients with colorectal carcinomas.

The majority of sporadic forms of colorectal carcinomas is characterized by deregulation of Wnt/ß-catenin signaling early in colorectal carcinogenesis. As a consequence, ITF-2B protein levels are increased in adenomas of these patients. However, ITF-2B protein levels are strongly reduced with increasing carcinoma stages, suggesting that reduction of ITF-2B protein is required for progression of adenomas to colorectal carcinomas. To find out if ITF-2B protein levels are correlated with the survival of patients with colorectal carcinomas, a tissue microarray containing samples from 213 colorectal carcinomas (T-categories T2 and T3) with corresponding survival information was stained with an ITF-2B antibody. In addition, we analyzed if detection of ITF-2B in microsatellite instable and microsatellite stable carcinomas as well as in colorectal carcinomas with KRAS mutations is correlated with survival. Detection of cytoplasmic ITF-2B protein was associated with better overall and progression free survival of patients with colorectal carcinomas (P=0.033 and 0.024, respectively). Multivariate Cox regression analysis revealed an increased risk to suffer from poor overall survival and recurrent disease if no cytoplasmic ITF-2B was detectable (HR=1.91; P=0.033 and HR=1.75; P=0.033, respectively). Similarly, patients with MSS carcinomas had a better overall survival, if they showed cytoplasmic positivity for ITF-2B (P=0.013). Remarkably, patients with colorectal carcinomas carrying KRAS mutations had a better overall and progression free survival rate if the carcinomas were positive for cytoplasmic ITF-2B (HR=4.71; P=0.002 and HR=2.57; P=0.024, respectively). These data suggest that cytoplasmic protein levels of ITF-2B could be used as a prognostic marker for patients with colorectal carcinomas.

Inactivation of Itf2 promotes intestinal tumorigenesis in Apc(Min/+) mice.

Deregulation of Wnt/ß-catenin signaling following inactivation of the adenomatous polyposis coli (APC) tumor suppressor gene is frequently found in colorectal cancer. We have previously shown that levels of ITF-2B, encoded by the ß-catenin target gene ITF2 that is located on the tumor suppressor gene locus 18q21, are increased in colonic adenomas with deregulated ß-catenin activity. However, during tumor progression ITF-2B levels are reduced, suggesting that ITF-2B interferes with tumor development. To investigate the role of ITF2 in intestinal tumorigenesis, we specifically inactivated Itf2 in the intestinal epithelium of Apc(Min/+) mice. We found that genetic disruption of Itf2 on the Apc(Min/+) background results in earlier death and a significant increase in tumor number and size in the small intestine. Based on these data Itf2 acts as a tumor suppressor gene of the intestinal tract that inhibits tumor initiation and growth.

Targeting cyclin dependent kinase 5 in hepatocellular carcinoma--A novel therapeutic approach.

BACKGROUND & AIMS: For a long time cyclin dependent kinase 5 (Cdk5) was thought to be exclusively important in neuronal cells. However, increasing evidence recently suggests a function of Cdk5 in cancer progression. In this study, we examined the role of Cdk5 and its therapeutic accessibility in hepatocellular carcinoma (HCC), a highly chemoresistant cancer with poor prognosis and paramount clinical importance in order to develop novel targeted therapies for systemic treatment. METHODS: Expression and activity of Cdk5 was analyzed in a human HCC tissue microarray, human patient samples and HCC cell lines. To characterize Cdk5 functions and signaling pathways in HCC, we applied genetic downregulation and pharmacologic inhibition in various approaches including cell based assays and mouse xenograft models. RESULTS: Expression and activity of Cdk5 was increased in human HCC tissues as compared to normal liver tissues. Functional ablation of Cdk5 significantly decreased HCC cell proliferation and clonogenic survival. Moreover, genetic and pharmacological inhibition of Cdk5 showed in vivo efficacy in HCC xenograft mouse models. Investigating the mechanisms behind these functional effects revealed that Cdk5 is most active in the nucleus of cells in G2/M phase. Cdk5 regulates DNA damage response by phosphorylating ataxia telangiectasia mutated (ATM) kinase and thereby influencing its downstream cascade. Consequently, combination of Cdk5 inhibition with DNA-damage-inducing chemotherapeutics synergistically inhibited HCC tumor progression in vitro and in vivo. CONCLUSIONS: In summary, we introduce Cdk5 as a novel drugable target for HCC treatment and suggest the combination of Cdk5 inhibition and DNA damaging agents as a novel therapeutic approach.

High-fat-diet-mediated dysbiosis promotes intestinal carcinogenesis independently of obesity.

Several features common to a Western lifestyle, including obesity and low levels of physical activity, are known risk factors for gastrointestinal cancers. There is substantial evidence suggesting that diet markedly affects the composition of the intestinal microbiota. Moreover, there is now unequivocal evidence linking dysbiosis to cancer development. However, the mechanisms by which high-fat diet (HFD)-mediated changes in the microbial community affect the severity of tumorigenesis in the gut remain to be determined. Here we demonstrate that an HFD promotes tumour progression in the small intestine of genetically susceptible, K-ras(G12Dint), mice independently of obesity. HFD consumption, in conjunction with K-ras mutation, mediated a shift in the composition of the gut microbiota, and this shift was associated with a decrease in Paneth-cell-mediated antimicrobial host defence that compromised dendritic cell recruitment and MHC class II molecule presentation in the gut-associated lymphoid tissues. When butyrate was administered to HFD-fed K-ras(G12Dint) mice, dendritic cell recruitment in the gut-associated lymphoid tissues was normalized, and tumour progression was attenuated. Importantly, deficiency in MYD88, a signalling adaptor for pattern recognition receptors and Toll-like receptors, blocked tumour progression. The transfer of faecal samples from HFD-fed mice with intestinal tumours to healthy adult K-ras(G12Dint) mice was sufficient to transmit disease in the absence of an HFD. Furthermore, treatment with antibiotics completely blocked HFD-induced tumour progression, suggesting that distinct shifts in the microbiota have a pivotal role in aggravating disease. Collectively, these data underscore the importance of the reciprocal interaction between host and environmental factors in selecting a microbiota that favours carcinogenesis, and they suggest that tumorigenesis is transmissible among genetically predisposed individuals.

Colorectal cancers mimic structural organization of normal colonic crypts.

Colonic crypts are stereotypical structures with distinct stem cell, proliferating, and differentiating compartments. Colorectal cancers derive from colonic crypt epithelia but, in contrast, form morphologically disarrayed glands. In this study, we investigated to which extent colorectal cancers phenocopy colonic crypt architecture and thus preserve structural organization of the normal intestinal epithelium. A subset of colon cancers showed crypt-like compartments with high WNT activity and nuclear ß-Catenin at the leading tumor edge, adjacent proliferation, and enhanced Cytokeratin 20 expression in most differentiated tumor epithelia of the tumor center. This architecture strongly depended on growth conditions, and was fully reproducible in mouse xenografts of cultured and primary colon cancer cells. Full crypt-like organization was associated with low tumor grade and was an independent prognostic marker of better survival in a collection of 221 colorectal cancers. Our findings suggest that full activation of preserved intestinal morphogenetic programs in colon cancer requires in vivo growth environments. Furthermore, crypt-like architecture was linked with less aggressive tumor biology, and may be useful to improve current colon cancer grading schemes.

Increased numbers of bone marrow-derived cells in parathyroid adenoma.

BACKGROUND: In primary hyperparathyroidism (PHPT), the increased levels of parathyroid hormone (PTH) result in mobilisation of bone-marrow-derived cells (BMCs) into peripheral blood. However, the fate of these cells is still unknown. MATERIALS AND METHODS: In this study, we sought to investigate cells with typical surface markers of BMCs within parathyroid adenomas (PA) of patients with primary hyperparathyroidism. We therefore investigated PA and normal parathyroid glands (NPG) of 15 patients with PHPT by immunohistochemistry and PCR. RESULTS: mRNA levels for CD31, CD34 and CD45 were significantly increased in PA compared to NPG. Immunohistochemical staining for CD31 and CD34 revealed a significantly higher vessel density in PA. Furthermore, scattered single cells expressing CD31, CD34 or CD45 were significantly augmented compared to normal parathyroid glands and directly correlated with vessel density. mRNA levels of SDF-1 was increased whereas its major inhibitor dipeptidylpeptidase IV (DPP IV) is decreased in PA, suggesting that the SDF-1 axis plays a role in the migration of BMCs into PA. CONCLUSION: These data indicate a possible role of BMCs in the pathophysiology of PA of patients with PHPT.

Evidence for a role of E-cadherin in suppressing liver carcinogenesis in mice and men.

The cell adhesion molecule E-cadherin has critical functions in development and carcinogenesis. Impaired expression of E-cadherin has been associated with disrupted tissue homeostasis, progression of cancer and a worse patient prognosis. So far, the role of E-cadherin in homeostasis and carcinogenesis of the liver is not well understood. By use of a mouse model with liver-specific deletion of E-cadherin and administration of the carcinogen diethylnitrosamine, we demonstrate that loss of E-cadherin expression in hepatocytes results in acceleration of the growth of hepatocellular carcinoma (HCC). In contrast, liver regeneration is not disturbed in mice lacking E-cadherin expression in hepatocytes. In human HCC, we observed four different expression patterns of E-cadherin. Notably, atypical cytosolic expression of E-cadherin was positively correlated with a poorer patient prognosis. The median overall survival of patients with HCC expressing E-cadherin on the membrane only was 221 weeks (95% confidence interval: 51-391) compared with 131 weeks in patients with cytosolic expression (95% confidence interval: 71-191 weeks; P < 0.05). In conclusion, we demonstrate that impaired expression of E-cadherin promotes hepatocellular carcinogenesis and is associated with a worse prognosis in humans.

Epithelial-mesenchymal transition induces endoplasmic-reticulum-stress response in human colorectal tumor cells.

Tumor cells are stressed by unfavorable environmental conditions like hypoxia or starvation. Driven by the resulting cellular stress tumor cells undergo epithelial-mesenchymal transition. Additionally, cellular stress is accompanied by endoplasmic reticulum-stress which induces an unfolded protein response. It is unknown if epithelial-mesenchymal transition and endoplasmic reticulum-stress are occurring as independent parallel events or if an interrelationship exists between both of them. Here, we show that in colorectal cancer cells endoplasmic reticulum-stress depends on the induction of ZEB-1, which is a main factor of epithelial-mesenchymal transition. In the absence of ZEB-1 colorectal cancer cells cannot mount endoplasmic reticulum-stress as a reaction on cellular stress situations like hypoxia or starvation. Thus, our data suggest that there is a hierarchy in the development of cellular stress which starts with the presence of environmental stress that induces epithelial-mesenchymal transition which allows finally endoplasmic reticulum-stress. This finding highlights the central role of epithelial-mesenchymal transition during the process of tumorigenesis as epithelial-mesenchymal transition is also associated with chemoresistance and cancer stemness. Consequently, endoplasmic reticulum-stress might be a well suited target for chemotherapy of colorectal cancers.