An Upstream Open Reading Frame in Phosphatase and Tensin Homolog Encodes a Circuit Breaker of Lactate Metabolism.

The metabolic role of micropeptides generated from untranslated regions remains unclear. Here we describe MP31, a micropeptide encoded by the upstream open reading frame (uORF) of phosphatase and tensin homolog (PTEN) acting as a "circuit breaker" that limits lactate-pyruvate conversion in mitochondria by competing with mitochondrial lactate dehydrogenase (mLDH) for nicotinamide adenine dinucleotide (NAD+). Knocking out the MP31 homolog in mice enhanced global lactate metabolism, manifesting as accelerated oxidative phosphorylation (OXPHOS) and increased lactate consumption and production. Conditional knockout (cKO) of MP31 homolog in mouse astrocytes initiated gliomagenesis and shortened the overall survival of the animals, establishing a tumor-suppressing role for MP31. Recombinant MP31 administered intraperitoneally penetrated the blood-brain barrier and inhibited mice GBM xenografts without neurological toxicity, suggesting the clinical implication and application of this micropeptide. Our findings reveal a novel mode of MP31-orchestrated lactate metabolism reprogramming in glioblastoma.

The micropeptide LEMP plays an evolutionarily conserved role in myogenesis.

In recent years, micropeptides have been increasingly identified as important regulators in various biological processes. However, whether micropeptides are functionally conserved remains largely unknown. Here, we uncovered a micropeptide with evolutionarily conserved roles in myogenesis. RNA-seq data analysis of proliferating mouse satellite cells (SCs) and differentiated myotubes identified a previously annotated lncRNA, MyolncR4 (1500011K16RIK), which is upregulated during muscle differentiation. Significantly, MyolncR4 is highly conserved across vertebrate species. Multiple lines of evidence demonstrate that MyolncR4 encodes a 56-aa micropeptide, which was named as LEMP (lncRNA encoded micropeptide). LEMP promotes muscle formation and regeneration in mouse. In zebrafish, MyolncR4 is enriched in developing somites and elimination of LEMP results in impaired muscle development, which could be efficiently rescued by expression of the mouse LEMP. Interestingly, LEMP is localized at both the plasma membrane and mitochondria, and associated with multiple mitochondrial proteins, suggestive of its involvement in mitochondrial functions. Together, our work uncovers a micropeptide that plays an evolutionarily conserved role in skeletal muscle differentiation, pinpointing the functional importance of this growing family of small peptides.

Notch signaling inhibition protects against LPS mediated osteolysis.

Chronic inflammatory responses have profound effects on the differentiation and activity of both the bone-forming osteoblasts and bone-resorbing osteoclasts. Importantly, inflammatory bone diseases characterized by clinical osteolysis promote bone resorption and decrease bone formation by uncoupling the process in favor of excess resorption. Notch signaling regulates osteoclast development and thus its manipulation has the potential to suppress resorptive potential. Here, we have utilized a genetic model of Notch inhibition in osteoclasts by expression of dnMAML to prevent formation of transcriptional complex essential for downstream Notch signaling. Using this model and LPS as a tool for experimental inflammatory osteolysis, we have demonstrated that dnMAML-expressing osteoclasts exhibited significantly lower maturation and resorption/functional potential ex vivo using TRAP staining and calcium phosphate coated surfaces. Moreover, we observed that while LPS stimulated the formation of wildtype osteoclasts pre-treated with RANKL, dnMAML expression produced resistance to osteoclast maturation after LPS stimulation. Genetically, Notch-inhibited animals showed a significantly lower TRAP and CTX-1 levels in serum after LPS treatment compared to the control groups in addition to a marked reduction in osteoclast surfaces in calvaria sections. This report provides evidence for modulation of Notch signaling activity to protect against inflammatory osteolysis. Taken together, the findings of this study will help guide the development of Notch signaling-based therapeutic approaches to prevent bone loss.

Vaccinia virus hijacks EGFR signalling to enhance virus spread through rapid and directed infected cell motility.

Cell motility is essential for viral dissemination1. Vaccinia virus (VACV), a close relative of smallpox virus, is thought to exploit cell motility as a means to enhance the spread of infection1. A single viral protein, F11L, contributes to this by blocking RhoA signalling to facilitate cell retraction2. However, F11L alone is not sufficient for VACV-induced cell motility, indicating that additional viral factors must be involved. Here, we show that the VACV epidermal growth factor homologue, VGF, promotes infected cell motility and the spread of viral infection. We found that VGF secreted from early infected cells is cleaved by ADAM10, after which it acts largely in a paracrine manner to direct cell motility at the leading edge of infection. Real-time tracking of cells infected in the presence of EGFR, MAPK, FAK and ADAM10 inhibitors or with VGF-deleted and F11-deleted viruses revealed defects in radial velocity and directional migration efficiency, leading to impaired cell-to-cell spread of infection. Furthermore, intravital imaging showed that virus spread and lesion formation are attenuated in the absence of VGF. Our results demonstrate how poxviruses hijack epidermal growth factor receptor-induced cell motility to promote rapid and efficient spread of infection in vitro and in vivo.

Molecular Basis of Gut Microbiome-Associated Colorectal Cancer: A Synthetic Perspective.

A significant challenge toward studies of the human microbiota involves establishing causal links between bacterial metabolites and human health and disease states. Certain strains of commensal Escherichia coli harbor the 54-kb clb gene cluster which codes for small molecules named precolibactins and colibactins. Several studies suggest colibactins are genotoxins and support a role for clb metabolites in colorectal cancer formation. Significant advances toward elucidating the structures and biosynthesis of the precolibactins and colibactins have been made using genetic approaches, but their full structures remain unknown. In this Perspective we describe recent synthetic efforts that have leveraged biosynthetic advances and shed light on the mechanism of action of clb metabolites. These studies indicate that deletion of the colibactin peptidase ClbP, a modification introduced to promote accumulation of precolibactins, leads to the production of non-genotoxic pyridone-based isolates derived from the diversion of linear biosynthetic intermediates toward alternative cyclization pathways. Furthermore, these studies suggest the active genotoxins (colibactins) are unsaturated imines that are potent DNA damaging agents, thereby confirming an earlier mechanism of action hypothesis. Although these imines have very recently been detected in bacterial extracts, they have to date confounded isolation. As the power of "meta-omics" approaches to natural products discovery further advance, we anticipate that chemical synthetic and biosynthetic studies will become increasingly interdependent.

Irisin regulates cardiac physiology in zebrafish.

Irisin is a myokine encoded in its precursor fibronectin type III domain containing 5 (FNDC5). It is abundantly expressed in cardiac and skeletal muscle, and is secreted upon the activation of peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1 alpha). We aimed to study the role of irisin on cardiac function and muscle protein regulation in zebrafish. Western blot analyses detected the presence of irisin protein (23 kDa) in zebrafish heart and skeletal muscle, and irisin immunoreactivity was detected in both tissues. Irisin siRNA treated samples did not show bands corresponding to irisin in zebrafish. In vitro studies found that treatment with irisin (0.1 nM) downregulated the expression of PGC-1 alpha, myostatin a, and b, while upregulating troponin C mRNA expression in zebrafish heart and skeletal muscle. Exogenous irisin (0.1 and 1 ng/g B.W) increased diastolic volume, heart rate and cardiac output, while knockdown of irisin (10 ng/g B.W) showed opposing effects on cardiovascular function. Irisin (1 and 10 ng/g B.W) downregulated PGC-1 alpha, myostatin a and b, and upregulated troponin C and troponin T2D mRNA expression. Meanwhile, knockdown of irisin showed opposing effects on troponin C, troponin T2D and myostatin a and b mRNAs in zebrafish heart and skeletal muscle. Collectively, these results identified muscle proteins as novel targets of irisin, and added irisin to the list of peptide modulators of cardiovascular physiology in zebrafish.

Adropin deficiency worsens HFD-induced metabolic defects.

The limited efficacy of current treatment methods and increased type 2 diabetes mellitus (T2DM) incidence constitute an incentive for investigating how metabolic homeostasis is maintained, to improve treatment efficacy and identify novel treatment methods. We analyzed a three-generation family of Chinese origin with the common feature of T2DM attacks and fatty pancreas (FP), alongside 19 unrelated patients with FP and 58 cases with T2DM for genetic variations in Enho, serum adropin, and relative Treg amounts. Functional studies with adropin knockout (AdrKO) in C57BL/6J mice were also performed. It showed serum adropin levels were significantly lower in FP and T2DM patients than in healthy subjects; relative Treg amounts were also significantly decreased in FP and T2DM patients, and positively associated with adropin (r=0.7220, P=0.0001). Sequencing revealed that the patients shared a Cys56Trp mutation in Enho. In vivo, adropin-deficiency was associated with increased severity of glucose homeostasis impairment and fat metabolism disorder. AdrKO mice exhibited reduced endothelial nitric oxide synthase (eNOS) phosphorylation (Ser1177), impaired glycosphingolipid biosynthesis, adipocytes infiltrating, and loss of Treg, and developed FP and T2DM. Adropin-deficiency contributed to loss of Treg and the development of FP disease and T2DM.

mTORC1 and muscle regeneration are regulated by the LINC00961-encoded SPAR polypeptide.

Although long non-coding RNAs (lncRNAs) are non-protein-coding transcripts by definition, recent studies have shown that a fraction of putative small open reading frames within lncRNAs are translated. However, the biological significance of these hidden polypeptides is still unclear. Here we identify and functionally characterize a novel polypeptide encoded by the lncRNA LINC00961. This polypeptide is conserved between human and mouse, is localized to the late endosome/lysosome and interacts with the lysosomal v-ATPase to negatively regulate mTORC1 activation. This regulation of mTORC1 is specific to activation of mTORC1 by amino acid stimulation, rather than by growth factors. Hence, we termed this polypeptide 'small regulatory polypeptide of amino acid response' (SPAR). We show that the SPAR-encoding lncRNA is highly expressed in a subset of tissues and use CRISPR/Cas9 engineering to develop a SPAR-polypeptide-specific knockout mouse while maintaining expression of the host lncRNA. We find that the SPAR-encoding lncRNA is downregulated in skeletal muscle upon acute injury, and using this in vivo model we establish that SPAR downregulation enables efficient activation of mTORC1 and promotes muscle regeneration. Our data provide a mechanism by which mTORC1 activation may be finely regulated in a tissue-specific manner in response to injury, and a paradigm by which lncRNAs encoding small polypeptides can modulate general biological pathways and processes to facilitate tissue-specific requirements, consistent with their restricted and highly regulated expression profile.

QRFP-Deficient Mice Are Hypophagic, Lean, Hypoactive and Exhibit Increased Anxiety-Like Behavior.

How the hypothalamus transmits hunger information to other brain regions to govern whole brain function to orchestrate feeding behavior has remained largely unknown. Our present study suggests the importance of a recently found lateral hypothalamic neuropeptide, QRFP, in this signaling. Qrfp-/- mice were hypophagic and lean, and exhibited increased anxiety-like behavior, and were hypoactive in novel circumstances as compared with wild type littermates. They also showed decreased wakefulness time in the early hours of the dark period. Histological studies suggested that QRFP neurons receive rich innervations from neurons in the arcuate nucleus which is a primary region for sensing the body's metabolic state by detecting levels of leptin, ghrelin and glucose. These observations suggest that QRFP is an important mediator that acts as a downstream mediator of the arcuate nucleus and regulates feeding behavior, mood, wakefulness and activity.

Loss of TFF1 promotes Helicobacter pylori-induced ß-catenin activation and gastric tumorigenesis.

Using in vitro and in vivo models, we investigated the role of TFF1 in suppressing H. pylori-mediated activation of oncogenic ß-catenin in gastric tumorigenesis. A reconstitution of TFF1 expression in gastric cancer cells decreased H. pylori-induced ß-catenin nuclear translocation, as compared to control (p < 0.001). These cells exhibited significantly lower ß-catenin transcriptional activity, measured by pTopFlash reporter, and induction of its target genes (CCND1 and c-MYC), as compared to control. Because of the role of AKT in regulating ß-catenin, we performed Western blot analysis and demonstrated that TFF1 reconstitution abrogates H. pylori-induced p-AKT (Ser473), p-ß-catenin (Ser552), c-MYC, and CCND1 protein levels. For in vivo validation, we utilized the Tff1-KO gastric neoplasm mouse model. Following infection with PMSS1 H. pylori strain, we detected an increase in the nuclear staining for ß-catenin and Ki-67 with a significant induction in the levels of Ccnd1 and c-Myc in the stomach of the Tff1-KO, as compared to Tff1-WT mice (p < 0.05). Only 10% of uninfected Tff1-KO mice, as opposed to one-third of H. pylori-infected Tff1-KO mice, developed invasive adenocarcinoma (p = 0.03). These findings suggest that loss of TFF1 could be a critical step in promoting the H. pylori-mediated oncogenic activation of ß-catenin and gastric tumorigenesis.

TFF2 deficiency exacerbates weight loss and alters immune cell and cytokine profiles in DSS colitis, and this cannot be rescued by wild-type bone marrow.

The trefoil factor TFF2 is a member of a tripartite family of small proteins that is produced by the stomach and the colon. Recombinant TFF2, when applied intrarectally in a rodent model of hapten colitis, hastens mucosal healing and reduces inflammatory indexes. Additionally, TFF2 is expressed in immune organs, supporting a potential immunomodulatory and reparative role in the bowel. In this study we confirm that TFF2 is expressed in the colon and is specifically enriched in epithelial cells relative to colonic leukocytes. TFF2-deficient, but not TFF1-deficient, mice exhibit a more severe response to acute or chronic dextran sulfate (DSS)-induced colitis that correlates with a 50% loss of expression of TFF3, the principal colonic trefoil. In addition, the response to acute colitis is associated with altered expression of IL-6 and IL-33, but not other inflammatory cytokines. While TFF2 can reduce macrophage responsiveness and block inflammatory cell recruitment to the colon, the major role in limiting the susceptibility to acute colitis appears to be maintenance of barrier function. Bone marrow transfer experiments demonstrate that leukocyte expression of TFF2 is not sufficient for prevention of colitis induction but, rather, that the gastrointestinal epithelium is the primary source of TFF2. Together, these findings illustrate that epithelial TFF2 is an important endogenous regulator of gut mucosal homeostasis that can modulate immune and epithelial compartments. Because of its extreme stability, even in the corrosive gut lumen, TFF2 is an attractive candidate as an oral therapeutic scaffold for future drug development in the treatment of inflammatory bowel disease.

Targeted disruption of a ring-infected erythrocyte surface antigen (RESA)-like export protein gene in Plasmodium falciparum confers stable chondroitin 4-sulfate cytoadherence capacity.

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family proteins mediate the adherence of infected erythrocytes to microvascular endothelia of various organs, including the placenta, thereby contributing to cerebral, placental, and other severe malaria pathogenesis. Several parasite proteins, including KAHRP and PfEMP3, play important roles in the cytoadherence by mediating the clustering of PfEMP1 in rigid knoblike structures on the infected erythrocyte surface. The lack of a subtelomeric region of chromosome 2 that contains kahrp and pfemp3 causes reduced cytoadherence. In this study, microarray transcriptome analysis showed that the absence of a gene cluster, comprising kahrp, pfemp3, and four other genes, results in the loss of parasitized erythrocytes adhering to chondroitin 4-sulfate (C4S). The role of one of these genes, PF3D7_0201600/PFB0080c, which encodes PHISTb (Plasmodium helical interspersed subtelomeric b) domain-containing RESA-like protein 1 expressed on the infected erythrocyte surface, was investigated. Disruption of PFB0080c resulted in increased var2csa transcription and VAR2CSA surface expression, leading to higher C4S-binding capacity of infected erythrocytes. Further, PFB0080c-knock-out parasites stably maintained the C4S adherence through many generations of growth. Although the majority of PFB0080c-knock-out parasites bound to C4S even after culturing for 6 months, a minor population bound to both C4S and CD36. These results strongly suggest that the loss of PFB0080c markedly compromises the var gene switching process, leading to a marked reduction in the switching rate and additional PfEMP1 expression by a minor population of parasites. PFB0080c interacts with VAR2CSA and modulates knob-associated Hsp40 expression. Thus, PFB0080c may regulate VAR2CSA expression through these processes. Overall, we conclude that PFB0080c regulates PfEMP1 expression and the parasite's cytoadherence.

Aurora kinase A promotes inflammation and tumorigenesis in mice and human gastric neoplasia.

BACKGROUND & AIMS: Chronic inflammation contributes to the pathogenesis of gastric tumorigenesis. The aurora kinase A (AURKA) gene is frequently amplified and overexpressed in gastrointestinal cancers. We investigated the roles of AURKA in inflammation and gastric tumorigenesis. METHODS: We used quantitative real-time reverse transcription polymerase chain reaction, immunofluorescence, immunohistochemistry, luciferase reporter, immunoblot, co-immunoprecipitation, and in vitro kinase assays to analyze AGS and MKN28 gastric cancer cells. We also analyzed Tff1(-/-) mice, growth of tumor xenografts, and human tissues. RESULTS: We correlated increased expression of AURKA with increased levels of tumor necrosis factor-α and inflammation in the gastric mucosa of Tff1(-/-) mice (r = 0.62; P = .0001). MLN8237, an investigational small-molecule selective inhibitor of AURKA, reduced nuclear staining of nuclear factor-κB (NF-κB) p65 in human gastric cancer samples and mouse epithelial cells, suppressed NF-κB reporter activity, and reduced expression of NF-κB target genes that regulate inflammation and cell survival. Inhibition of AURKA also reduced growth of xenograft tumors from human gastric cancer cells in mice and reversed the development of gastric tumors in Tff1(-/-) mice. AURKA was found to regulate NF-κB activity by binding directly and phosphorylating IκBα in cells. Premalignant and malignant lesions from the gastric mucosa of patients had increased levels of AURKA protein and nuclear NF-κB, compared with healthy gastric tissue. CONCLUSIONS: In analyses of gastric cancer cell lines, human tissue samples, and mouse models, we found AURKA to be up-regulated during chronic inflammation to promote activation of NF-κB and tumorigenesis. AURKA inhibitors might be developed as therapeutic agents for gastric cancer.

Persistence of LPS-induced lung inflammation in surfactant protein-C-deficient mice.

Pulmonary surfactant protein-C (SP-C) gene-targeted mice (Sftpc(-/-)) develop progressive lung inflammation and remodeling. We hypothesized that SP-C deficiency reduces the ability to suppress repetitive inflammatory injury. Sftpc(+/+) and Sftpc(-/-) mice given three doses of bacterial LPS developed airway and airspace inflammation, which was more intense in the Sftpc(-/-) mice at 3 and 5 days after the final dose. Compared with Sftpc(+/+)mice, inflammatory injury persisted in the lungs of Sftpc(-/-) mice 30 days after the final LPS challenge. Sftpc(-/-) mice showed LPS-induced airway goblet cell hyperplasia with increased detection of Sam pointed Ets domain and FoxA3 transcription factors. Sftpc(-/-) type II alveolar epithelial cells had increased cytokine expression after LPS exposure relative to Sftpc(+/+) cells, indicating that type II cell dysfunction contributes to inflammatory sensitivity. Microarray analyses of isolated type II cells identified a pattern of enhanced expression of inflammatory genes consistent with an intrinsic low-level inflammation resulting from SP-C deficiency. SP-C-containing clinical surfactant extract (Survanta) or SP-C/phospholipid vesicles blocked LPS signaling through the LPS receptor (Toll-like receptor [TLR] 4/CD14/MD2) in human embryonic kidney 293T cells, indicating that SP-C blocks LPS-induced cytokine production by a TLR4-dependent mechanism. Phospholipid vesicles alone did not modify the TLR4 response. In vivo deficiency of SP-C leads to inflammation, increased cytokine production by type II cells, and persistent inflammation after repetitive LPS stimulation.

Prominin 1/CD133 endothelium sustains growth of proneural glioma.

In glioblastoma high expression of the CD133 gene, also called Prominin1, is associated with poor prognosis. The PDGF-driven proneural group represents a subset of glioblastoma in which CD133 is not overexpressed. Interestingly, this particular subset shows a relatively good prognosis. As with many other tumors, gliobastoma is believed to arise and be maintained by a restricted population of stem-like cancer cells that express the CD133 transmembrane protein. The significance of CD133(+) cells for gliomagenesis is controversial because of conflicting supporting evidence. Contributing to this inconsistency is the fact that the isolation of CD133(+) cells has largely relied on the use of antibodies against ill-defined glycosylated epitopes of CD133. To overcome this problem, we used a knock-in lacZ reporter mouse, Prom1(lacZ/+) , to track Prom1(+) cells in the brain. We found that Prom1 (prominin1, murine CD133 homologue) is expressed by cells that express markers characteristic of the neuronal, glial or vascular lineages. In proneural tumors derived from injection of RCAS-PDGF into the brains of tv-a;Ink4a-Arf(-/-) Prom1(lacZ/+) mice, Prom1(+) cells expressed markers for astrocytes or endothelial cells. Mice co-transplanted with proneural tumor sphere cells and Prom1(+) endothelium had a significantly increased tumor burden and more vascular proliferation (angiogenesis) than those co-transplanted with Prom1(-) endothelium. We also identified specific genes in Prom1(+) endothelium that code for endothelial signaling modulators that were not overexpressed in Prom1(-) endothelium. These factors may support proneural tumor progression and could be potential targets for anti-angiogenic therapy.

Response to stress in early tumor colonization modulates switching of CD133-positive and CD133-negative subpopulations in a human metastatic colon cancer cell line, SW620.

According to the cancer stem cell (CSC) model, higher CD133 expression in tumor tissue is associated with metastasis and poor prognosis in colon cancer. As such, the CD133-positive (CD133(+)) subpopulation of cancer cells is believed to play a central role in tumor development and metastatic progression. Although CD133(+) cells are believed to display more CSC-like behavior and be solely responsible for tumor colonization, recent research indicates that CD133(-) cells from metastatic colon tumors not only also possess colonization capacity but also promote the growth of larger tumors in a mouse model than CD133(+) cells, suggesting that an alternative mechanism of metastasis exists. This study investigated this possibility by examining the cell viability, tumorigenicity, and proliferation and growth capacity of the CD133(+) and CD133(-) subpopulations of the SW620 cell line, a human metastatic colon cancer cell line, in both an in vitro cell model and an in vivo mouse model. While both SW620 (CD133-) and SW620(CD133+) cells were found to engage in bidirectional cell-type switching in reaction to exposure to environmental stressors, including hypoxia, a cell adhesion-free environment, and extracellular matrix stimulation, both in vitro and in vivo, CD133(-) cells were found to have a growth advantage during early colonization due to their greater resistance to proliferation inhibition. Based on these findings, a hypothetical model in which colon cancer cells engage in cell-type switching in reaction to exposure to environmental stressors is proposed. Such switching may provide a survival advantage during early colonization, as well as that explain previous conflicting observations.

Trefoil factor 2 negatively regulates type 1 immunity against Toxoplasma gondii.

IL-12-mediated type 1 inflammation confers host protection against the parasitic protozoan Toxoplasma gondii. However, production of IFN-γ, another type 1 inflammatory cytokine, also drives lethality from excessive injury to the intestinal epithelium. As mechanisms that restore epithelial barrier function following infection remain poorly understood, this study investigated the role of trefoil factor 2 (TFF2), a well-established regulator of mucosal tissue repair. Paradoxically, TFF2 antagonized IL-12 release from dendritic cells (DCs) and macrophages, which protected TFF2-deficient (TFF2(-/-)) mice from T. gondii pathogenesis. Dysregulated intestinal homeostasis in naive TFF2(-/-) mice correlated with increased IL-12/23p40 levels and enhanced T cell recruitment at baseline. Infected TFF2(-/-) mice displayed low rates of parasite replication and reduced gut immunopathology, whereas wild-type (WT) mice experienced disseminated infection and lethal ileitis. p38 MAPK activation and IL-12p70 production was more robust from TFF2(-/-)CD8+ DC compared with WT CD8+ DC and treatment of WT DC with rTFF2 suppressed TLR-induced IL-12/23p40 production. Neutralization of IFN-γ and IL-12 in TFF2(-/-) animals abrogated resistance shown by enhanced parasite replication and infection-induced morbidity. Hence, TFF2 regulated intestinal barrier function and type 1 cytokine release from myeloid phagocytes, which dictated the outcome of oral T. gondii infection in mice.

Trefoil factor 2 rapidly induces interleukin 33 to promote type 2 immunity during allergic asthma and hookworm infection.

The molecular mechanisms that drive mucosal T helper type 2 (T(H)2) responses against parasitic helminths and allergens remain unclear. In this study, we demonstrate in mice that TFF2 (trefoil factor 2), an epithelial cell-derived repair molecule, is needed for the control of lung injury caused by the hookworm parasite Nippostrongylus brasiliensis and for type 2 immunity after infection. TFF2 is also necessary for the rapid production of IL-33, a T(H)2-promoting cytokine, by lung epithelia, alveolar macrophages, and inflammatory dendritic cells in infected mice. TFF2 also increases the severity of allergic lung disease caused by house dust mite antigens or IL-13. Moreover, TFF2 messenger RNA expression is significantly increased in nasal mucosal brushings during asthma exacerbations in children. These experiments extend the biological functions of TFF2 from tissue repair to the initiation and maintenance of mucosal T(H)2 responses.

CD133(+) liver tumor-initiating cells promote tumor angiogenesis, growth, and self-renewal through neurotensin/interleukin-8/CXCL1 signaling.

UNLABELLED: A novel theory in the field of tumor biology postulates that cancer growth is driven by a population of stem-like cells, called tumor-initiating cells (TICs). We previously identified a TIC population derived from hepatocellular carcinoma (HCC) that is characterized by membrane expression of CD133. Here, we describe a novel mechanism by which these cells mediate tumor growth and angiogenesis by systematic comparison of the gene expression profiles between sorted CD133 liver subpopulations through genome-wide microarray analysis. A significantly dysregulated interleukin-8 (IL-8) signaling network was identified in CD133(+) liver TICs obtained from HCC clinical samples and cell lines. IL-8 was found to be overexpressed at both the genomic and proteomic levels in CD133(+) cells isolated from HCC cell lines or clinical samples. Functional studies found enhanced IL-8 secretion in CD133(+) liver TICs to exhibit a greater ability to self-renew, induce tumor angiogenesis, and initiate tumors. In further support of these observations, IL-8 repression in CD133(+) liver TICs by knockdown or neutralizing antibody abolished these effects. Subsequent studies of the IL-8 functional network identified neurotensin (NTS) and CXCL1 to be preferentially expressed in CD133(+) liver TICs. Addition of exogenous NTS resulted in concomitant up-regulation of IL-8 and CXCL1 with simultaneous activation of p-ERK1/2 and RAF-1, both key components of the mitogen-activated protein kinase (MAPK) pathway. Enhanced IL-8 secretion by CD133(+) liver TICs can in turn activate an IL-8-dependent feedback loop that signals through the MAPK pathway. Further, in its role as a liver TIC marker CD133 also plays a functional part in regulating tumorigenesis of liver TICs by way of regulating NTS, IL-8, CXCL1, and MAPK signaling. CONCLUSION: CD133(+) liver TICs promote angiogenesis, tumorigenesis, and self-renewal through NTS-induced activation of the IL-8 signaling cascade.

CD133(-) cells, derived from a single human colon cancer cell line, are more resistant to 5-fluorouracil (FU) than CD133(+) cells, dependent on the ß1-integrin signaling.

BACKGROUND AND AIM: Recently, the cancer stem cells (CSCs) theory has been proposed, and CD133 has been suggested as a potential marker of CSCs in various cancer types. In the present study, we aimed evaluate CD133 as a potential marker of colorectal CSCs and, for this purpose, isolated CD133(+) and CD133(-) cells from a single colorectal cancer cell line, and compared their features, especially related to the tumor-forming and differentiation abilities, and the sensitivity to chemotherapy. METHODS AND RESULTS: CD133(+) cells had higher in vivo tumor-forming ability than CD133(-) cells, and in culture, they progressively differentiated into CD133(-) cells, but not vice-versa. On the other hand, CD133(-) cells were more resistant to 5-fluorouracil (FU) treatment than CD133(+) cells, and it was found to be dependent on the higher expression of ß1-integrins, and consequently, higher ability to bind collagen. Disruption of the ß1-integrin function abrogated the chemoresistance. CONCLUSION: From the present results, we concluded that colorectal cancer CD133(+) cells, although showing some features of CSCs, are not more resistant to 5-FU than CD133(-) cells. Therefore, definite conclusions can not be drawn yet, but it is strongly suggestive that CD133 should not be used as a single CSC marker of colorectal cancer.