title: Survival advantages conferred to colon cancer cells by E-selectin-induced activation of the PI3K-NFκB survival axis downstream of Death receptor-3.
abstract: BACKGROUND
  Extravasation of circulating cancer cells is a key event of metastatic dissemination that is initiated by the adhesion of cancer cells to endothelial cells. It requires interactions between adhesion receptors on endothelial cells and their counter-receptors on cancer cells. Notably, E-selectin, a major endothelial adhesion receptor, interacts with Death receptor-3 present on metastatic colon carcinoma cells. This interaction confers metastatic properties to colon cancer cells by promoting the adhesion of cancer cells to endothelial cells and triggering the activation of the pro-migratory p38 and pro-survival ERK pathways in the cancer cells. In the present study, we investigated further the mechanisms by which the E-selectin-activated pathways downstream of DR3 confer a survival advantage to colon cancer cells.
  
  
  METHODS
  Cell survival has been ascertained by using the WST-1 assay and by evaluating the activation of the PI3 kinase/NFκB survival axis. Apoptosis has been assayed by determining DNA fragmentation by Hoechst staining and by measuring cleavage of caspases-8 and -3. DR3 isoforms have been identified by PCR. For more precise quantification, targeted PCR reactions were carried out, and the amplified products were analyzed by automated chip-based microcapillary electrophoresis on an Agilent 2100 Bioanalyzer instrument.
  
  
  RESULTS
  Interaction between DR3-expressing HT29 colon carcinoma cells and E-selectin induces the activation of the PI3K/Akt pathway. Moreover, p65/RelA, the anti-apoptotic subunit of NFκB, is rapidly translocated to the nucleus in response to E-selectin. This translocation is impaired by the PI3K inhibitor LY294002. Furthermore, inhibition of the PI3K/Akt pathway increases the cleavage of caspase 8 in colon cancer cells treated with E-selectin and this effect is still further increased when both ERK and PI3K pathways are concomitantly inhibited. Intriguingly, metastatic colon cancer cell lines such as HT29 and SW620 express higher levels of a splice variant of DR3 that has no trans-membrane domain and no death domain.
  
  
  CONCLUSIONS
  Colon cancer cells acquire an increased capacity to survive via the activation of the PI3K/NFκB pathway following the stimulation of DR3 by E-selectin. Generation of a DR3 splice variant devoid of death domain can further contribute to protect against apoptosis.
authors: Le Centre de recherche en cancérologie de l'Université Laval et Centre de recherche du CHUQ, l'Hôtel-Dieu de Québec, 9 rue McMahon, Québec G1R 2J6 Canada. Jacques.Huot@fmed.ulaval.ca
authors: Nicolas
authors: N
authors: Porquet
authors: Andrée
authors: A
authors: Poirier
authors: François
authors: F
authors: Houle
authors: Anne-Laure
authors: AL
authors: Pin
authors: Stéphanie
authors: S
authors: Gout
authors: Pierre-Luc
authors: PL
authors: Tremblay
authors: Eric R
authors: ER
authors: Paquet
authors: Roscoe
authors: R
authors: Klinck
authors: François A
authors: FA
authors: Auger
authors: Jacques
authors: J
authors: Huot
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000502:physiology; D002448:Cell Adhesion; D002470:Cell Survival / Q000502:physiology; D002867:Chromones / Q000494:pharmacology; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D019040:E-Selectin / Q000378:metabolism*; D019073:HT29 Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D019169:Jurkat Cells; D020935:MAP Kinase Signaling System; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism*; D009362:Neoplasm Metastasis; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D020033:Protein Isoforms; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D053219:Receptors, Tumor Necrosis Factor, Member 25 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D002867:Chromones; D019040:E-Selectin; D009025:Morpholines; D016328:NF-kappa B; D020033:Protein Isoforms; D053219:Receptors, Tumor Necrosis Factor, Member 25; C546936:SELE protein, human; C506033:TNFRSF25 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D019061:src-Family Kinases; D051057:Proto-Oncogene Proteins c-akt