Hedgehog signaling pathway and gastrointestinal stem cell signaling network (Review)Katoh, Yuriko ; Katoh, Masaru
doi: 10.3892/ijmm.18.6.1019pmid: N/A
Hedgehog, BMP/TGFβ, FGF, WNT and Notch signaling pathways constitute the stem cell signaling network, which plays a key role in a variety of processes, such as embryogenesis, maintenance of adult tissue homeostasis, tissue repair during chronic persistent inflammation, and carcinogenesis. Sonic hedgehog (SHH), Indian hedgehog (IHH) and Desert hedgehog (DHH) bind to PTCH1/PTCH or PTCH2 receptor to release Smoothened (SMO) signal transducer from Patched-dependent suppression. SMO then activates STK36 serine/threonine kinase to stabilize GLI family members and to phosphorylate SUFU for nuclear accumulation of GLI. Hedgehog signaling activation leads to GLI-dependent transcriptional activation of target genes, such as GLI1, PTCH1, CCND2, FOXL1, JAG2 and SFRP1. GLI1-dependent positive feedback loop combined with PTCH1-dependent negative feedback loop gives rise to transient proliferation of Hedgehog target cells. Iguana homologs (DZIP1 and DZIP1L) and Costal-2 homologs (KIF7 and KIF27) are identified by comparative integromics. SHH-dependent parietal cell proliferation is implicated in gastric mucosal repair during chronic Helicobacter pylori infection. BMP-RUNX3 signaling induces IHH expression in surface differentiated epithelial cells of stomach and intestine. Hedgehog signals from epithelial cells then induces FOXL1-mediated BMP4 upregulation in mesenchymal cells. Hedgehog signaling is frequently activated in esophageal cancer, gastric cancer and pancreatic cancer due to transcriptional upregulation of Hedgehog ligands and epigenetic silencing of HHIP1/HHIP gene, encoding the Hedgehog inhibitor. However, Hedgehog signaling is rarely activated in colorectal cancer due to negative regulation by the canonical WNT signaling pathway. Hedgehog signaling molecules or targets, such as SHH, IHH, HHIP1, PTCH1 and GLI1, are applied as biomarkers for cancer diagnostics, prognostics and therapeutics. Small-molecule inhibitors for SMO or STK36 are suitable to be used for treatment of Hedgehog-dependent cancer.
Current and future approaches for the therapeutic targeting of metastasis (Review)Germanov, Elitza ; Berman, Jason N.; Guernsey, Duane L.
doi: 10.3892/ijmm.18.6.1025pmid: N/A
Metastasis is the process whereby cancer cells disseminate and establish secondary tumors at distant sites from the primary tumor and is estimated to be responsible for ≈90% of all cancer deaths. Cancers with metastatic spread are frequently resistant to conventional chemotherapeutic approaches, underlining the urgent need for novel treatments in these diseases. Recent advances in understanding the mechanisms underlining both the intrinsic cellular and extrinsic micro-environmental factors contributing to the metastatic process have resulted in the identification of a number of molecular targets for the development of specific anti-metastatic therapeutic strategies. These targets include intracellular enzymes such as the protein tyrosine kinases, cell surface receptors and their ligands, and elements of the extracellular matrix such as pro-angiogenic factors, protease enzymes and cytokines. Many of these pathways interact with each other, with the possibility of multiple downstream antineoplastic consequences as well as the potential for synergistic effects by targeting more than one of these factors. This review outlines several of the promising targets, and provides examples, of how these targets are being exploited as anti-metastatic therapies in conjunction with conventional treatments.
Molecular profiles of the mouse postnatal development of the esophageal epithelium showing delayed growth startDaiko, Hiroyuki ; Isohata, Noriyuki ; Sano, Masayuki ; Aoyagi, Kazuhiko ; Ogawa, Kenji ; Kameoka, Shingo ; Yoshida, Teruhiko ; Sasaki, Hiroki
doi: 10.3892/ijmm.18.6.1057pmid: N/A
Studies on molecular mechanisms of self-renewal in normal stem cells are required for understanding the cancer stem cell. Self-renewal in many kinds of normal stem cells might be accelerated in the growth of a young organism and in the repair of damaged tissue. This study examined whether the esophagus in growing neonates provides an experimental system for studies on epithelial stem cell renewal. The esophageal epithelium consists of 3 layers, from the luminal side to the bottom: the differentiated, epibasal and basal cell layers. The basal cell layer is known to contain the stem cells for the esophageal epithelium. This basic architecture is observed both in mice and humans. We investigated the basal cells in the mouse neonate by immunostaining with a basal cell marker, nerve growth factor receptor (Ngfr), and compared the basal cell content in the esophageal epithelium between mice and humans. A mouse esophageal epithelial cell primary culture system was developed for studies on the basal cell growth and keratinocyte differentiation, and microarray analysis was conducted for obtaining expression profiles of the basal cells. It was revealed that the growth of the esophageal epithelium begins from postnatal day 3, and that the timing is consistent with membrane localization of Ngfr in the basal cell. An increase in the basal cell number by Ngf treatment is observed in in vitro mouse esophageal epithelium cultures. Furthermore, mRNA overexpression of Pdgfrb encoding platelet derived growth factor receptor β and Egfr encoding epidermal growth factor receptor is associated with the timing of the growth of the esophageal epithelium in the neonatal mice. This study provides a new experimental model for studies on the growth of the basal cells, which are considered to include the stem cells, and on the enlargement of the body size in young organisms.
Genetic and pathologic characteristics of gastrointestinal stromal tumors in extragastric lesionsCho, Songde ; Kitadai, Yasuhiko ; Yoshida, Shigeto ; Tanaka, Shinji ; Yoshihara, Masaharu ; Yoshida, Kazuhiro ; Chayama, Kazuaki
doi: 10.3892/ijmm.18.6.1067pmid: N/A
The goal of this study was to investigate differences in the clinicopathologic and genetic characteristics of gastric and extragastric gastrointestinal stromal tumors (GISTs). We evaluated 13 extragastric GISTs and compared them with 56 gastric GISTs, which were described previously. DNA was extracted from paraffin-embedded tumor specimens, and exons 9, 11, 13, and 17 of the KIT gene and exons 12 and 18 of the platelet-derived growth factor receptor α (PDGFRA) gene were amplified by polymerase chain reaction and sequenced. Immunohistochemistry was performed for KIT, CD34, Ki-67 (as a marker of cell proliferation), and CD31 (as a marker of microvessel density), and apoptosis was assessed by in situ DNA nick end-labeling. Of the 13 extragastric GISTs 7 (54%) had a mutation in exon 11 of KIT, and 2 (15%) had a mutation in exon 13 of KIT. Deletions in exon 11 of KIT were the most common mutation encountered in the extragastric GISTs. The extragastric GISTs, especially small intestinal GISTs, showed larger deletions, leading to deletions of amino acid residues in the KIT protein, and higher vascularity than did the gastric GISTs. These data suggest that extragastric GISTs differ from gastric GISTs with respect to associated mutations and angiogenic activity.
Comano's (Trentino) thermal water interferes with interleukin-6 production and secretion and with cytokeratin-16 expression by cultured human psoriatic keratinocytes: Further potential mechanisms of its anti-psoriatic actionChiarini, Anna ; Dal Pra, Ilaria ; Pacchiana, Raffaella ; Zumiani, Giuseppe ; Zanoni, Mauro ; Armato, Ubaldo
doi: 10.3892/ijmm.18.6.1073pmid: N/A
Thermal balneotherapy with Comano's spa water (CW; Trentino, Italy) is used for psoriasis and other skin disorders but its mechanisms of action are mostly unknown. Previously, we showed that CW can interfere with the expression and secretion of various VEGF-A isoforms by cultured human psoriatic epidermal keratinocytes. In this study, confluent cultures of IL-6-hypersecreting keratino-cytes isolated from 6 psoriatic patients were exposed for 11-15 days to DMEM, the chemicals of which had been dissolved in either deionised water (DW-DMEM, controls) or CW (CW-DMEM, treated cells). As detected by means of immunocytochemistry, Western immunoblotting, and ELISA assays, the intracellular levels and secretion rates of IL-6 were drastically curtailed in the CW-DMEM-incubated keratinocytes and in their cell-conditioned media. A nearly maximal inhibition of IL-6 release had already been induced by a CW fraction in the DMEM as low as 25%. CW exposure also promptly, intensely, and persistently down-regulated the expression of cytokeratin-16 (CK-16), a marker associated with keratinocyte psoriatic phenotype. Hence, CW balneotherapy may beneficially affect the clinical manifestations of psoriasis via an attenuation of the local deregulation of several cytokines/chemokines, including IL-6 and VEGF-A isoforms, and of a concurrent, abnormal cell differentiation program entailing the expression, amongst other proteins, of CK-16.
DNA topoisomerase IIα (TOP2A) inhibitors up-regulate fatty acid synthase gene expression in SK-Br3 breast cancer cells: In vitro evidence for a ‘functional amplicon’ involving FAS, Her-2/neu and TOP2A genesMenendez, Javier A.; Vellon, Luciano A.; Lupu, Ruth A.
doi: 10.3892/ijmm.18.6.1081pmid: N/A
Fatty acid synthase (FAS), the key metabolic multi-enzyme that is responsible for the terminal catalytic step in the de novo fatty acid biosynthesis, plays an active role in the development, maintenance, and enhancement of the malignant phenotype in a subset of breast carcinomas. We recently described that a molecular bi-directional cross-talk between FAS and the Her-2/neu (erbB-2) oncogene is taking place at the level of transcription, translation, and activity in breast cancer cells. Because Her-2/neu has been linked with altered sensitivity to cytotoxic drugs, we envisioned that FAS gene expression may represent a novel predictive molecular factor for breast cancer response to chemotherapy in a Her-2/neu-related manner. We herein evaluated whether chemotherapy-induced cell damage acts in an epigenetic fashion by inducing changes in the transcriptional activation of FAS gene in breast cancer cells. To evaluate this option, FAS- and Her-2/neu-overexpressing SK-Br3 breast cancer cells were transiently transfected with a FAS promoter-reporter construct (FAS-Luciferase) harboring all the elements necessary for high level expression in cancer cells. SK-Br3 cells cultured in the presence of topoisomerase IIα (TOP2A) inhibitors doxorubicin and etopoxide (VP-16) demonstrated a 2- to 3-fold increase in FAS promoter activity when compared with control cells growing in drug-free culture conditions. We failed to observe any significant activation of FAS promoter following exposure to the anti-metabolite 5-fluorouracil, the alkylating drug cisplatin, or the microtubule interfering-agents paclitaxel and vincristine. Moreover, the up-regulatory effects of TOP2A inhibitors on the transcriptional activation of FAS gene expression were not significantly decreased when the FAS promoter was damaged at the sterol regulatory element binding protein (SREBP)-binding site. Considering that FAS inhibition produces profound inhibition of DNA replication and S-phase progression in cancer cells, we finally asked whether a cross-talk between TOP2A and FAS could exhibit a Her-2/neu-related bi-directional nature. TOP2A protein levels were decreased during treatment with the anti-Her-2/neu antibody trastuzumab while, concomitantly, FAS promoter activity and FAS protein expression were significantly reduced. Of note, when the expression levels of TOP2A protein were analyzed following exposure of SK-Br3 cells to increasing concentrations of the novel slow-binding FAS inhibitor C75, a dose-dependent reduction in TOP2A expression was observed. Although FAS gene is not physically located in the Her-2/neu-TOP2A amplicon, our present findings strongly suggest that a tight functional association between FAS, Her-2/neu and TOP2A genes is taking place in a subset of breast carcinoma cells.