MicroRNA-496 and Mechanistic Target of Rapamycin Expression are Associated with Type 2 Diabetes Mellitus and Obesity in Elderly People.

BACKGROUND: Mechanistic target of rapamycin (mTOR) regulates lipid and glucose metabolism thus playing a key role in metabolic diseases like type 2 diabetes mellitus (T2DM). Recently, we demonstrated a functional interaction of microRNA-496 (miR-496) with mTOR and its impact on the regulation of human ageing. OBJECTIVES: As T2DM is most prevalent in older adults, we hypothesized that miR-496 may also have an impact on mTOR regulation in T2DM. METHODS: Based on real-time PCR and enzyme-linked immunosorbent assay, mTOR gene and protein expression as well as miR-496 expression were monitored in peripheral blood mononuclear cells (PBMC) from T2DM patients (median age: 71) and healthy age- and BMI matched controls (median age: 69). -Results: We demonstrated significant upregulation of phospho-mTOR and P70S6 Kinase (P70S6K) levels and significant downregulation of miR-496 in PBMC from elderly T2DM patients in comparison to a BMI and age-matched control cohort. Moreover, significant upregulation of phospho-mTOR protein and significant downregulation of miR-496 were observed in advanced stages of obesity. CONCLUSIONS: BMI-dependent upregulation of mTOR and the inverse expression profile of miR-496 observed in elderly T2DM patients suggest a correlation with T2DM. Hence, our results indicate a potential association of miR-496 with mTOR expression in elderly T2DM patients and obesity. Since phosphorylation of P70S6K was also elevated in T2DM patients, we conclude that mTOR signaling through TORC1 may be affected in the regulation of T2DM.

MicroRNA target prediction: theory and practice.

The present study is one of the few that includes tissue samples in the evaluation of target prediction algorithms designed to detect microRNA (miRNA) sequences that might interact with particular messenger RNA (mRNA) sequences. Twelve different target prediction tools were used to find miRNA sequences that might interact with CCL20 gene expression. Different algorithms predicted controversial miRNA sequences for CCL20 regulation due to a different weighting of parameters. Hsa-miR-21 and hsa-miR-145 suggested by four or more programs were chosen for further investigation. Possible real interaction of these miRNA sequences with CCL20 gene expression was monitored using luciferase assays and expression analyses of tissue samples of colorectal adenocarcinoma by either qRT-PCR or ELISA. Folding status of seed-binding sites in complete mRNA and 3'UTR of CCL20 was predicted. Prediction of miRNA expression was attempted based on CCL20 expression data. Eight of the target prediction tools forecasted a role for hsa-miR-21 and four mentioned hsa-miR-145 in CCL20 gene regulation. Laboratory experimentation showed that CCL20 may serve as a target of hsa-miR-21 but not hsa-miR-145. Expression of the molecules resulted in no clear assertion. Folding of seed-binding sites was predicted to be relatively constant for the complete mRNA and 3'UTR. Predicting miRNA expression based on target gene expression was impossible. This might be attributable to the fact that effects of miRNA activity may oscillate between gene product repression and activation. Additional systematic studies are needed to address this issue.

Chemokine receptor CCR6 expression is regulated by miR-518a-5p in colorectal cancer cells.

BACKGROUND: Recently, involvement of the chemokine/receptor system CCL20/CCR6 in colorectal cancer (CRC) progression was shown. Here, we analyzed the functional interaction of miRNA-518-5p (miR-518a-5p) with CCR6 and its impact on CCR6 expression in CRC cells. METHODS: MiR-518a-5p was identified by computer software to potentially interact with CCR6. Hence, functional implications of miR-518a-5p with the 3'UTR of CCR6 were analyzed using the Dual Luciferase Reporter assay system. Confirmation of the predicted target site for miR-518a-5p was achieved by site-directed mutagenesis of the seed sequence in the 3'UTR of CCR6 and subsequent application of the mutated seed sequence in a luciferase assay with miR-518a-5p mimics. Accordingly, two CRC cell lines (Caco-2 and HT-29) were transfected with miR-518a-5p miRNA mimics and gene and protein expression of CCR6 was monitored using qRT PCR and immunocytochemistry, respectively. RESULTS: Addition of miR-518a-5p led to significant down-regulation of luciferase activity (P < 0.05), which was significantly reversed in a reporter test system containing the mutated seed sequences in the 3'UTR of CCR6. Following transfection of CRC cell lines with miR-518a-5p mimics and subsequent monitoring of CCR6 expression showed significant down-regulation of CCR6 mRNA and CCR6 protein expression in both CRC cell lines under investigation (P < 0.05). CONCLUSIONS: We have shown that miR-518a-5p functionally interacts with CCR6 and that transfection of CRC cells with miR-518a-5p leads to significant CCR6 down-regulation. Consequently, CCR6 expression is regulated by miR-518a-5p in CRC cells indicating that regulation of CCR6 expression by miR-518a-5p might be a regulatory mechanism involved in CRC pathogenesis.

The Interplay of TGF-ß1 and Cholesterol Orchestrating Hepatocyte Cell Fate, EMT, and Signals for HSC Activation.

BACKGROUND & AIMS: Transforming growth factor-ß1 (TGF-ß1) plays important roles in chronic liver diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD involves various biological processes including dysfunctional cholesterol metabolism and contributes to progression to metabolic dysfunction-associated steatohepatitis and hepatocellular carcinoma. However, the reciprocal regulation of TGF-ß1 signaling and cholesterol metabolism in MASLD is yet unknown. METHODS: Changes in transcription of genes associated with cholesterol metabolism were assessed by RNA sequencing of murine hepatocyte cell line (alpha mouse liver 12/AML12) and mouse primary hepatocytes treated with TGF-ß1. Functional assays were performed on AML12 cells (untreated, TGF-ß1 treated, or subjected to cholesterol enrichment [CE] or cholesterol depletion [CD]), and on mice injected with adenovirus-associated virus 8-control/TGF-ß1. RESULTS: TGF-ß1 inhibited messenger RNA expression of several cholesterol metabolism regulatory genes, including rate-limiting enzymes of cholesterol biosynthesis in AML12 cells, mouse primary hepatocytes, and adenovirus-associated virus-TGF-ß1-treated mice. Total cholesterol levels and lipid droplet accumulation in AML12 cells and liver tissue also were reduced upon TGF-ß1 treatment. Smad2/3 phosphorylation after 2 hours of TGF-ß1 treatment persisted after CE or CD and was mildly increased after CD, whereas TGF-ß1-mediated AKT phosphorylation (30 min) was inhibited by CE. Furthermore, CE protected AML12 cells from several effects mediated by 72 hours of incubation with TGF-ß1, including epithelial-mesenchymal transition, actin polymerization, and apoptosis. CD mimicked the outcome of long-term TGF-ß1 administration, an effect that was blocked by an inhibitor of the type I TGF-ß receptor. In addition, the supernatant of CE- or CD-treated AML12 cells inhibited or promoted, respectively, the activation of LX-2 hepatic stellate cells. CONCLUSIONS: TGF-ß1 inhibits cholesterol metabolism whereas cholesterol attenuates TGF-ß1 downstream effects in hepatocytes.

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.

Changes in CXCL12/CXCR4-chemokine expression during onset of colorectal malignancies.

Chemokines have been proposed to contribute to tumour growth and metastatic spread of several cancer entities. Here, we examined the relative levels of CXCL12/CXCR4 in resection specimens from patients with different malignant and non-malignant colorectal diseases as well as colorectal liver metastases (CRLM). CXCL12/CXCR4 mRNA and protein expression profiles were assessed by quantitative real-time PCR, Western blot analysis, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry in resection specimens from patients with ulcerative colitis (UC; n = 15), colorectal adenoma (CRA; n = 15), colorectal adenocarcinoma (CRC; n = 47) and CRLM (n = 16). Corresponding non-affected tissues served as control. In contrast to UC tissues, CXCL12 showed a distinct down-regulation in CRA, CRC and CRLM specimens, whereas the corresponding receptor CXCR4 demonstrated a significant up-regulation in CRC and CRLM related to corresponding non-affected tissues (p < 0.05, respectively). Our results strongly suggest an association between CXCL12/CXCR4 expression and the induction of CRA, CRC and the development of CRLM. Therefore, CXCR4 may be a potential target for specific therapeutic interventions.

An aging and p53 related marker: HOXA5 promoter methylation negatively correlates with mRNA and protein expression in old age.

The process of aging has been associated with differential patterns of DNA methylation which relate to changes in gene expression. Hence, we aimed to identify genes with significant age-related methylation differences and to study their mRNA and protein expression profile. Genome-wide DNA methylation analysis was performed with the Illumina Infinium Methylation EPIC BeadChip Microarray on bisulfite-converted DNA prepared from monocytes derived from young (average age: 23.8 yrs) and old (average age: 81.5 yrs) volunteers that are separated by at least 50 years of age difference, n=4, respectively. Differentially methylated CpG sites were assigned to the associated genes and validated by deep sequencing analysis (n=20). Demonstrating an age-associated significant increase of methylation in the promoter region (p=1x10-8), Homeobox A5 (HOXA5), also known to activate p53, emerged as an interesting candidate for further expression analyses by Realtime PCR, ELISA and Western Blot Analysis (n=30, respectively). Consistent with its hypermethylation we observed significant HOXA5 mRNA downregulation (p=0.0053) correlating with significant p53 downregulation (p=0.0431) in the old cohort. Moreover, we observed a significant change in HOXA5 protein expression (p=3x10-5) negatively correlating with age and promoter methylation thus qualifying HOXA5 for an eligible p53-related aging marker.

CCL20/CCR6 expression profile in pancreatic cancer.

BACKGROUND: CCL20 and its receptor CCR6 have been shown to play a role in the onset, development and metastatic spread of various gastrointestinal malignancies. In this study, the expression profile and clinical significance of the CCL20/CCR6 system in distinct benign, pre-malignant and malignant pancreatic tissues was investigated. METHODS: Using RealTime-PCR, enzyme-linked immunosorbent assay (ELISA), Western Blot and immunohistochemistry, we have analyzed the expression profile of CCL20/CCR6 in resection specimens from patients with chronic pancreatitis (CP) (n = 22), pancreatic cystadenoma (PA) (n = 11) and pancreatic carcinoma (PCA) (n = 25) as well as in the respective matched normal pancreatic tissues. RESULTS: CCL20 mRNA and protein was weakly expressed in normal pancreatic tissues and CP and PA specimens but significantly up-regulated in PCA (8-fold) as compared to the matched normal tissue (P < 0.05). Moreover, CCL20 mRNA and protein expression was significantly associated with advanced T-category in patients with PCA (P < 0.05). CCR6 mRNA showed a significant up-regulation in all three disease entities as compared to normal tissues (P < 0.05, respectively). CONCLUSION: CCL20 and CCR6 were significantly up-regulated in PCA as compared to the normal pancreatic tissue and CCL20 was significantly associated with advanced T-category in PCA patients. This suggests that CCL20 and CCR6 play a role in the development and progression of PCA and may constitute potential targets for novel treatment strategies.

The chemokine CCL20 and its receptor CCR6 in human malignancy with focus on colorectal cancer.

Chemokines are a superfamily of small chemotactic cytokines, which interact with their G-protein-coupled receptors. These interactions regulate multiple physiological functions, particularly tissue architecture and compartment-specific migration of white blood cells. It has been found that the chemokine/chemokine receptor system has been utilized by cancer cells for migration and metastasis. The chemokine receptor CCR6 is expressed in colorectal cancer and several other cancer types, and stimulation by its physiological chemokine ligand CCL20 has been reported to promote cancer cell proliferation and migration in vitro. Moreover, CCR6/CCL20 interactions apparently play a role in organ selective liver metastasis of colorectal cancer. Here, we review the literature on expression patterns of CCL20 and CCR6 and their physiological interactions as well as the currently presumed role of CCR6 and CCL20 in the formation of colorectal cancer liver metastasis, providing a potential basis for novel treatment strategies.

ELR+ CXC chemokine expression in benign and malignant colorectal conditions.

BACKGROUND: CXCR2 chemokine ligands CXCL1, CXCL5 and CXCL6 were shown to be involved in chemoattraction, inflammatory responses, tumor growth and angiogenesis. Here, we comparatively analyzed their expression profile in resection specimens from patients with colorectal adenoma (CRA) (n = 30) as well as colorectal carcinoma (CRC) (n = 48) and corresponding colorectal liver metastases (CRLM) (n = 16). METHODS: Chemokine expression was assessed by microdissection, quantitative real-time PCR (Q-RT-PCR), the enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC). RESULTS: In contrast to CXCL6, we demonstrated CXCL1 and CXCL5 mRNA and protein expression to be significantly up-regulated in CRC and CRLM tissue specimens in relation to their matched tumor neighbor tissues. Moreover, both chemokine ligands were demonstrated to be significantly higher expressed in CRC tissues than in CRA tissues thus indicating a progressive increase in the transition from the premalignant condition to the development of the malignant status. Although a comparative analysis of the CXCL1/CXCL5 protein expression profiles in CRC patients revealed that the absolute expression level of CXCL1 was significantly higher in comparison to CXCL5, mRNA- and protein overexpression of CXCL5 in CRC and CRLM tissues was much more pronounced (80- and 60- fold in CRC tissues, respectively) in comparison to CXCL1 (5- and 3.5- fold in CRC tissues, respectively). CONCLUSION: Our results demonstrate a significant association between CXCL1 and CXCL5 expression with CRC and CRLM suggesting for both chemokine ligands a potential role in the progression from CRA to CRC and thus, in the initiation of CRC.

Enhanced ENA-78 and IL-8 expression in patients with malignant pancreatic diseases.

BACKGROUND/AIM: Pancreatic cancer is characterized by perineural invasion, early lymph node and liver metastases, and an extremely dismal prognosis. In the present study we aimed at investigating the expression profile of pro-inflammatory and angiogenic CXC chemokines as potential factors contributing to the aggressive biology of this gastrointestinal malignancy. METHODS: Protein expression profiles of the CXC chemokines growth-related oncogene alpha (GRO-alpha/CXCL1), epithelial cell-derived neutrophil-activating peptide-78 (ENA-78/CXCL5), granulocyte chemoattractant protein-2 (GCP-2/CXCL6), neutrophil-activating protein-2 (NAP-2/CXCL7), and interleukin-8 (IL-8/CXCL8) were assessed by enzyme-linked immunosorbent assay in pancreatic carcinoma, cancer of the papilla of Vater, pancreatic cystadenoma, and chronic pancreatitis specimens. RESULTS: IL-8 and ENA-78 protein expression was most pronounced in pancreatic carcinoma specimens, showing an 11-fold and 17-fold overexpression in comparison with non-affected neighbouring tissues, a 66-fold and 24-fold upregulation compared to pancreatic cystadenoma, and a 6-fold and 9-fold overexpression with respect to chronic pancreatitis, respectively (p < 0.05 between all groups). In addition, a close correlation between IL-8 and ENA-78 protein expression and advanced pancreatic carcinomas in relation to the T category was evident (p < 0.05). CONCLUSION: Our results demonstrate that ELR+ CXC chemokines are differentially expressed in malignant and non-malignant human pancreatic specimens, suggesting a potential contribution of these chemokines to the pathogenesis of pancreatic carcinoma.

Increased growth factor expression after hepatic and pancreatic resection.

Removal of the primary tumour is suggested to associate with an enhanced tumour growth of residual micrometastases. Recent data focus on growth factors that may be released in response to surgery-stimulating receptors of residual tumour cells. Vascular endothelial (VEGF) and hepatocyte growth factor (HGF) are potent inducers of angiogenesis. The two factors are necessary for wound healing and the promotion of tumour growth. This study was designed to determine growth factor serum levels in patients before, during and after major abdominal surgery. It was recently shown that simultaneous hepatic and pancreatic resection led to poor liver regeneration. As growth factors may be involved in these findings we compared the growth factor levels after liver resection with the levels in patients after pancreatic resection. Forty patients were accrued before hepatopancreatic surgery (hepatic resection n=20 and pancreatic resection n=20). Blood samples were taken from each patient immediately prior to surgery, during the operation and on the postoperative days (POD) 1-3, 5 and 10. To examine the wound fluid, liquid from the wound drains was collected on POD 3. Using ELISA the concentration of the angiogenic cytokines HGF and VEGF165 was determined. After the liver and pancreatic resections, circulating HGF and VEGF165 were increased. We found significantly higher levels of HGF on POD 1-3 (p<0.01), compared to preoperative results with a peak on POD 2. After measuring the postoperative VEGF165 levels we found significantly higher levels of circulating VEGF165 on POD 1-5 (p<0.01) compared to the preoperative levels. On comparing liver with pancreatic resection we did not detect significantly different levels of the two growth factors in the two groups. VEGF165 and HGF concentrations measured during the operation demonstrated no change. HGF and VEGF165 levels detected in the wound fluid on POD 3 were approximately 10 times higher than the preoperative serum levels, respectively. In summary, our data show increased VEGF165 and HGF levels after hepatopancreatic surgery. Notably, the lack of an impact of the type of organ resection on the concentration-time curve of the two growth factors suggest that high postoperative growth factor levels are part of normal wound healing and systemic inflammation. Thus, the proangiogenetic potential of growth factors may account for accelerated tumour growth when residual tumour cells are exposed to high levels of VEGF165 and HGF.

Cytokine-mediated modulation of the hepatic miRNome: miR-146b-5p is an IL-6-inducible miRNA with multiple targets.

Interleukin-6 (IL-6)-type cytokines play important roles in liver (patho-)biology. For instance, they regulate the acute phase response to inflammatory signals and are involved in hepatocarcinogenesis. Much is known about the regulation of protein-coding genes by cytokines whereas their effects on the miRNome is less well understood. We performed a microarray screen to identify microRNAs (miRNAs) in human hepatocytes which are modulated by IL-6-type cytokines. Using samples of 2 donors, 27 and 68 miRNAs (out of 1,733) were found to be differentially expressed upon stimulation with hyper-IL-6 (HIL-6) for up to 72 h, with an overlap of 15 commonly regulated miRNAs. qPCR validation revealed that miR-146b-5p was also consistently up-regulated in hepatocytes derived from 2 other donors. Interestingly, miR-146b-5p (but not miR-146a-5p) was induced by IL-6-type cytokines (HIL-6 and OSM) in non-transformed liver-derived PH5CH8 and THLE2 cells and in Huh-7 hepatoma cells, but not in HepG2 or Hep3B hepatoma cells. We did not find evidence for a differential regulation of miR-146b-5p expression by promoter methylation, also when analyzing the TCGA data set on liver cancer samples. Inducible overexpression of miR-146b-5p in PH5CH8 cells followed by RNA-Seq analysis revealed effects on multiple mRNAs, including those encoding IRAK1 and TRAF6 crucial for Toll-like receptor signaling. Indeed, LPS-mediated signaling was attenuated upon overexpression of miR-146b-5p, suggesting a regulatory loop to modulate inflammatory signaling in hepatocytes. Further validation experiments suggest DNAJC6, MAGEE1, MPHOSPH6, PPP2R1B, SLC10A3, SNRNP27, and TIMM17B to be novel targets for miR-146b-5p (and miR-146a-5p).

Correlation of IL-8 with induction, progression and metastatic potential of colorectal cancer.

AIM: To investigate the expression profile of IL-8 in inflammatory and malignant colorectal diseases to evaluate its potential role in the regulation of colorectal cancer (CRC) and the development of colorectal liver metastases (CRLM). METHODS: IL-8 expression was assessed by quantitative real-time PCR (Q-RT-PCR) and the enzyme-linked immunosorbent assay (ELISA) in resected specimens from patients with ulcerative colitis (UC, n = 6) colorectal adenomas (CRA, n = 8), different stages of colorectal cancer (n = 48) as well as synchronous and metachronous CRLM along with their corresponding primary colorectal tumors (n = 16). RESULTS: IL-8 mRNA and protein expression was significantly up-regulated in all pathological colorectal entities investigated compared with the corresponding neighboring tissues. However, in the CRC specimens IL-8 revealed a significantly more pronounced overexpression in relation to the CRA and UC tissues with an average 30-fold IL-8 protein up-regulation in the CRC specimens in comparison to the CRA tissues. Moreover, IL-8 expression revealed a close correlation with tumor grading. Most interestingly, IL-8 up-regulation was most enhanced in synchronous and metachronous CRLM, if compared with the corresponding primary CRC tissues. Herein, an up to 80-fold IL-8 overexpression in individual metachronous metastases compared to normal tumor neighbor tissues was found. CONCLUSION: Our results strongly suggest an association between IL-8 expression, induction and progression of colorectal carcinoma and the development of colorectal liver metastases.

Chemokine expression in hepatocellular carcinoma versus colorectal liver metastases.

AIM: To evaluate and compare the expression profiles of CXCL12 (SDF-1), CCL19 (MIP-3beta), CCL20 (MIP-3alpha) and CCL21 (6Ckine, Exodus2) and their receptors on RNA and protein levels in hepatocellular carcinoma (HCC) versus colorectal liver metastases (CRLM) and to elucidate their impact on the carcinogenesis and progression of malignant liver diseases. METHODS: Chemokine expression was analyzed by RT-PCR and ELISA in 11 cases of HCC specimens and in 23 cases of CRLM and corresponding adjacent non-tumorous liver tissues, respectively. Expressions of their receptors CXCR4, CCR6 and CCR7 were analyzed by RT-PCR and Western blot analysis in the same cases of HCC and CRLM. RESULTS: Significant up-regulation for CCL20/CCR6 was detected in both cancer types. Moreover, CCL20 demonstrated significant overexpression in CRLM in relation to the HCC tissues. Being significantly up-regulated only in CRLM, CXCR4 displayed an aberrant expression pattern with respect to the HCC tissues. CONCLUSION: Correlation of CXCR4 expression with CRLM suggests CXCR4 as a potential predictive factor for CRLM. High level expression of CCL20 and its receptor CCR6 in HCC and CRLM with marked up-regulation of CCL20 in CRLM in relation to HCC tissues indicates involvement of the CCL20/CCR6 ligand-receptor pair in the carcinogenesis and progression of hepatic malignancies.

Chemokine/chemokine receptor pair CCL20/CCR6 in human colorectal malignancy: An overview.

Chemokines belong to a superfamily of small, cytokine-like proteins, which induce multiple physiological functions, particularly cytoskeletal rearrangement and compartment-specific migration through their interaction with G-protein-coupled receptors. Chemokines and their receptors have been widely acknowledged as essential and selective mediators in leukocyte migration in inflammatory response. It is now established that the chemokine/chemokine receptor system is also used by cancer cells to direct lymphatic and haematogenous spreading and additionally has an impact on the site of metastatic growth of different tumours. In recent years an increasing number of studies have drawn attention to CC-chemokine cysteine motif chemokine ligand 20 (CCL20) and its physiological sole receptor CCR6 to play a role in the onset, development and metastatic spread of various gastrointestinal cancer entities. Among various cancer types CCR6 was also demonstrated to be significantly overexpressed in colorectal cancer (CRC) and stimulation by its physiological ligand CCL20 has been reported to promote CRC cell proliferation and migration in vitro. Further, the CCL20/CCR6 system apparently plays a role in the organ-selective liver metastasis of CRC. Here we review the literature on expression patterns of CCL20 and CCR6 and their physiological interactions as well as the currently presumed role of CCL20 and CCR6 in the formation of CRC and the development of liver metastasis, providing a potential basis for novel treatment strategies.

CXCL12/CXCR4 display an inverse mRNA expression profile in gastric carcinoma that correlates with tumor progression.

Chemokines and their receptors have been shown to contribute to tumor growth and metastatic spread in various gastrointestinal cancer entities. In the present study, the mRNA expression profiles and clinical significance of chemokine ligand CXCL12 and its corresponding receptor CXCR4 were investigated in patients with gastric cancer (GC). Using quantitative polymerase chain reaction, the expression profile of CXCL12/CXCR4 was analyzed in resection specimens from the patients with GC (n=66) and in corresponding normal gastric tissues. Upon investigating CXCL12/CXCR4 mRNA expression levels in the GC tissues, significant downregulation of CXCL12 expression was demonstrated (P<0.05), whereas CXCR4 mRNA expression was shown to be significantly upregulated (P<0.05). Likewise, in gastric carcinoma patients undergoing neoadjuvant chemotherapy, CXCR4 expression was found to be significantly upregulated (P<0.05), whereas in GC patients with lymph and vein infiltration, CXCL12 mRNA expression was significantly downregulated (P<0.05). These results demonstrate a significant inverse association between the development and progress of GC and CXCL12/CXCR4 mRNA expression. CXCR4 mRNA upregulation was promoted under the effect of neoadjuvant chemotherapy prior to surgery in GC patients, whereas higher tumor stages with lymph and vein infiltration negatively affected CXCL12 mRNA expression.

microRNA-496 - A new, potentially aging-relevant regulator of mTOR.

Recent findings strongly support a role for small regulatory RNAs in the regulation of human lifespan yet little information exists about the precise underlying mechanisms. Although extensive studies on model organisms have indicated that reduced activity of the nutrient response pathway, for example as a result of dietary restriction, can extend lifespan through the suppression of the protein kinase mechanistic target of rapamycin (mTOR), it still is subject of debate whether this mechanism is operative in humans as well. Here, we present findings indicating that human microRNA (miR)-496 targets 2 sites within the human mTOR 3'UTR. Coexpression of miR-496 with different fusion transcripts, consisting of the luciferase transcript and either wild-type mTOR 3'UTR or mTOR 3'UTR transcript with the miR-496 binding sites singly or combined mutated, confirmed this prediction and revealed cooperativity between the 2 binding sites. miR-496 reduced the mTOR protein level in HeLa-K cells, and the levels of miR-496 and mTOR protein were inversely correlated in Peripheral Blood Mononuclear Cells (PBMC), with old individuals (n = 40) harbouring high levels of miR-496 relative to young individuals (n = 40). Together, these findings point to the possibility that miR-496 is involved in the regulation of human aging through the control of mTOR.

Text mining, a race against time? An attempt to quantify possible variations in text corpora of medical publications throughout the years.

BACKGROUND: The continuous growth of medical sciences literature indicates the need for automated text analysis. Scientific writing which is neither unitary, transcending social situation nor defined by a timeless idea is subject to constant change as it develops in response to evolving knowledge, aims at different goals, and embodies different assumptions about nature and communication. The objective of this study was to evaluate whether publication dates should be considered when performing text mining. METHODS: A search of PUBMED for combined references to chemokine identifiers and particular cancer related terms was conducted to detect changes over the past 36 years. Text analyses were performed using freeware available from the World Wide Web. TOEFL Scores of territories hosting institutional affiliations as well as various readability indices were investigated. Further assessment was conducted using Principal Component Analysis. Laboratory examination was performed to evaluate the quality of attempts to extract content from the examined linguistic features. RESULTS: The PUBMED search yielded a total of 14,420 abstracts (3,190,219 words). The range of findings in laboratory experimentation were coherent with the variability of the results described in the analyzed body of literature. Increased concurrence of chemokine identifiers together with cancer related terms was found at the abstract and sentence level, whereas complexity of sentences remained fairly stable. CONCLUSIONS: The findings of the present study indicate that concurrent references to chemokines and cancer increased over time whereas text complexity remained stable.

Systematic mutation analysis of KIAA0767 and KIAA1646 in chromosome 22q-linked periodic catatonia.

BACKGROUND: Periodic catatonia is a familial subtype of schizophrenia characterized by hyperkinetic and akinetic episodes, followed by a catatonic residual syndrome. The phenotype has been evaluated in two independent genome-wide linkage scans with evidence for a major locus on chromosome 15q15, and a second independent locus on chromosome 22qtel. METHODS: In the positional and brain-expressed candidate genes KIAA0767 and KIAA1646, we searched for variants in the complete exons and adjacent splice-junctions as well as in parts of the 5'- and 3'-untranslated regions by means of a systematic mutation screening in individuals from chromosome 22q-linked pedigrees. RESULTS: The mutation scan revealed 24 single nucleotide polymorphisms, among them two rare codon variants (KIAA0767: S159I; KIAA1646: V338G). However, both were neither found segregating with the disease in the respective pedigree nor found at a significant frequency in a case-control association sample. CONCLUSION: Starting from linkage signals at chromosome22qtel in periodic catatonia, we screened two positional brain-expressed candidate genes for genetic variation. Our study excludes genetic variations in the coding and putative promoter regions of KIAA0767 and KIAA1646 as causative factors for periodic catatonia.