title: Prostaglandin E2Activates YAP and a Positive-Signaling Loop to Promote Colon Regeneration After Colitis but Also Carcinogenesis in Mice.
abstract: Prostaglandin E2(PGE2) is mediator of inflammation that regulates tissue regeneration, but its continual activation has been associated with carcinogenesis. Little is known about factors in the PGE2signaling pathway that contribute to tumor formation. We investigated whether yes-associated protein 1 (YAP1), a transcriptional co-activator in the Hippo signaling pathway, mediates PGE2function.
  
  
  
  DLD-1 and SW480 colon cancer cell lines were transfected with vectors expressing transgenes or small hairpin RNAs and incubated with recombinant PGE2, with or without pharmacologic inhibitors of signaling proteins, and analyzed by immunoblot, immunofluorescence, quantitative reverse-transcription polymerase chain reaction, transcriptional reporter, and proliferation assays. Dextran sodium sulfate (DSS) was given to induce colitis in C57/BL6 (control) mice, as well as in mice with disruption of the hydroxyprostaglandin dehydrogenase 15 gene (15-PGDH-knockout mice), Yap1 gene (YAP-knockout mice), and double-knockout mice. Some mice also were given indomethacin to block PGE2synthesis. 15-PGDH knockout mice were crossed with mice with intestine-specific disruption of the salvador family WW domain containing 1 gene (Sav1), which encodes an activator of Hippo signaling. We performed immunohistochemical analyses of colon biopsy samples from 26 patients with colitis-associated cancer and 51 age-and sex-matched patients with colorectal cancer (without colitis).
  
  
  
  Incubation of colon cancer cell lines with PGE2led to phosphorylation of cyclic adenosine monophosphate-responsive element binding protein 1 and increased levels of YAP1 messenger RNA, protein, and YAP1 transcriptional activity. This led to increased transcription of the prostaglandin-endoperoxide synthase 2 gene (PTGS2 or cyclooxygenase 2) and prostaglandin E-receptor 4 gene (PTGER4 or EP4). Incubation with PGE2promoted proliferation of colon cancer cell lines, but not cells with knockdown of YAP1. Control mice developed colitis after administration of DSS, but injection of PGE2led to colon regeneration in these mice. However, YAP-knockout mice did not regenerate colon tissues and died soon after administration of DSS. 15-PGDH-knockout mice regenerated colon tissues more rapidly than control mice after withdrawal of DSS, and had faster recovery of body weight, colon length, and colitis histology scores. These effects were reversed by injection of indomethacin. SAV1-knockout or 15-PGDH-knockout mice did not develop spontaneous tumors after colitis induction, but SAV1/15-PGDH double-knockout mice developed polyps that eventually progressed to carcinoma in situ. Administration of indomethacin to these mice prevented spontaneous tumor formation. Levels of PGE2correlated with those of YAP levels in human sporadic colorectal tumors and colitis-associated tumors.
  
  
  
  PGE2signaling increases the expression and transcriptional activities of YAP1, leading to increased expression of cyclooxygenase 2 and EP4 to activate a positive signaling loop. This pathway promotes proliferation of colon cancer cell lines and colon tissue regeneration in mice with colitis. Constitutive activation of this pathway led to formation of polyps and colon tumors in mice.
authors.affiliation: Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea; National Creative Research Initiatives Center, Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea; Biomedical Research Center, Asan Institute for Life Sciences, Seoul, South Korea.
authors.forename: Han-Byul
authors.initials: HB
authors.lastname: Kim
authors.affiliation: National Creative Research Initiatives Center, Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea.
authors.forename: Minchul
authors.initials: M
authors.lastname: Kim
authors.affiliation: Biomedical Research Center, Asan Institute for Life Sciences, Seoul, South Korea; Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Park
authors.affiliation: Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea; Biomedical Research Center, Asan Institute for Life Sciences, Seoul, South Korea.
authors.forename: Intae
authors.initials: I
authors.lastname: Park
authors.affiliation: National Creative Research Initiatives Center, Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea.
authors.forename: Tackhoon
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Gastroenterology, Haeundae Paik Hospital, Inje University, Busan, South Korea.
authors.forename: Sung-Yeun
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Cho
authors.affiliation: National Creative Research Initiatives Center, Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea.
authors.forename: DaeHee
authors.initials: D
authors.lastname: Hwang
authors.affiliation: Biomedical Research Center, Asan Institute for Life Sciences, Seoul, South Korea.
authors.forename: Jin-Hak
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Medicine and Comprehensive Cancer Center, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, Ohio.
authors.forename: Sanford D
authors.initials: SD
authors.lastname: Markowitz
authors.affiliation: Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Hwang
authors.affiliation: Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.affiliation: National Creative Research Initiatives Center, Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea. Electronic address: daesiklim@kaist.ac.kr.
authors.forename: Dae-Sik
authors.initials: DS
authors.lastname: Lim
authors.affiliation: Biomedical Research Center, Asan Institute for Life Sciences, Seoul, South Korea; Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea; Department of Convergence Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea. Electronic address: sjmyung@amc.seoul.kr.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Myung
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000187:drug effects* / Q000235:genetics; D000818:Animals; D063646:Carcinogenesis / Q000187:drug effects / Q000235:genetics; D016022:Case-Control Studies; D018797:Cell Cycle Proteins / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects* / Q000235:genetics; D003092:Colitis / Q000139:chemically induced; D003106:Colon / Q000187:drug effects* / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000235:genetics*; D051546:Cyclooxygenase 2; D016264:Dextran Sulfate / Q000633:toxicity; D015232:Dinoprostone / Q000494:pharmacology*; D005246:Feedback; D005455:Fluorescent Antibody Technique; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000235:genetics; D015151:Immunoblotting; D007150:Immunohistochemistry; D020935:MAP Kinase Signaling System; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B; D010750:Phosphoproteins / Q000187:drug effects* / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger / Q000187:drug effects* / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype; D012038:Regeneration / Q000187:drug effects* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D015854:Up-Regulation; D000091102:YAP-Signaling Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D016328:NF-kappa B; D010750:Phosphoproteins; D012333:RNA, Messenger; D058309:Receptors, Prostaglandin E, EP4 Subtype; C485935:Sav1 protein, mouse; D000091102:YAP-Signaling Proteins; C486223:Yap1 protein, mouse; D016264:Dextran Sulfate; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase; D051546:Cyclooxygenase 2; D051057:Proto-Oncogene Proteins c-akt; D015232:Dinoprostone
keywords: Inflammation; Mouse Model; Tumorigenesis; Villus Regeneration