title: FAM96A is a novel pro-apoptotic tumor suppressor in gastrointestinal stromal tumors.
abstract: The ability to escape apoptosis is a hallmark of cancer-initiating cells and a key factor of resistance to oncolytic therapy. Here, we identify FAM96A as a ubiquitous, evolutionarily conserved apoptosome-activating protein and investigate its potential pro-apoptotic tumor suppressor function in gastrointestinal stromal tumors (GISTs). Interaction between FAM96A and apoptotic peptidase activating factor 1 (APAF1) was identified in yeast two-hybrid screen and further studied by deletion mutants, glutathione-S-transferase pull-down, co-immunoprecipitation and immunofluorescence. Effects of FAM96A overexpression and knock-down on apoptosis sensitivity were examined in cancer cells and zebrafish embryos. Expression of FAM96A in GISTs and histogenetically related cells including interstitial cells of Cajal (ICCs), "fibroblast-like cells" (FLCs) and ICC stem cells (ICC-SCs) was investigated by Northern blotting, reverse transcription-polymerase chain reaction, immunohistochemistry and Western immunoblotting. Tumorigenicity of GIST cells and transformed murine ICC-SCs stably transduced to re-express FAM96A was studied by xeno- and allografting into immunocompromised mice. FAM96A was found to bind APAF1 and to enhance the induction of mitochondrial apoptosis. FAM96A protein or mRNA was dramatically reduced or lost in 106 of 108 GIST samples representing three independent patient cohorts. Whereas ICCs, ICC-SCs and FLCs, the presumed normal counterparts of GIST, were found to robustly express FAM96A protein and mRNA, FAM96A expression was much reduced in tumorigenic ICC-SCs. Re-expression of FAM96A in GIST cells and transformed ICC-SCs increased apoptosis sensitivity and diminished tumorigenicity. Our data suggest FAM96A is a novel pro-apoptotic tumor suppressor that is lost during GIST tumorigenesis.
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Schwamb
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Pick
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Sara Beatriz Mateus
authors.initials: SB
authors.lastname: Fernández
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Völp
authors.affiliation: Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University, Frankfurt, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Heering
authors.affiliation: Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University, Frankfurt, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Dötsch
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Bösser
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Jung
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Rasa
authors.initials: R
authors.lastname: Beinoraviciute-Kellner
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Josephine
authors.initials: J
authors.lastname: Wesely
authors.affiliation: Department of Medical Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, Im Neuenheimer Feld 305, Heidelberg, Germany.
authors.forename: Inka
authors.initials: I
authors.lastname: Zörnig
authors.affiliation: Max-Planck Institute of Immunobiology, Stuebeweg 51, Freiburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hammerschmidt
authors.affiliation: Max-Planck Institute of Immunobiology, Stuebeweg 51, Freiburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Nowak
authors.affiliation: Institute of Pathology, University Hospital Heidelberg, Im Neuenheimer Feld 224, Heidelberg, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Penzel
authors.affiliation: Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, Graz, a-8036, Austria.
authors.forename: Kurt
authors.initials: K
authors.lastname: Zatloukal
authors.affiliation: Deutsches Krebsforschungszentrum DKFZ (B060), Im Neuenheimer Feld 280, Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Joos
authors.affiliation: Institute for Pathology, University Hospital Erlangen, Krankenhausstrasse 8-10, Erlangen, Germany.
authors.forename: Ralf Joachim
authors.initials: RJ
authors.lastname: Rieker
authors.affiliation: Institute for Pathology, University Hospital Erlangen, Krankenhausstrasse 8-10, Erlangen, Germany.
authors.forename: Abbas
authors.initials: A
authors.lastname: Agaimy
authors.affiliation: Institute for Pathology, University Hospital Erlangen, Krankenhausstrasse 8-10, Erlangen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Söder
authors.affiliation: Department of Surgery, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: K Marie
authors.initials: KM
authors.lastname: Reid-Lombardo
authors.affiliation: Department of Surgery, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Kendrick
authors.affiliation: Center for Individualized Medicine and Gastroenterology Research Unit, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Bardsley
authors.affiliation: Center for Individualized Medicine and Gastroenterology Research Unit, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Center for Individualized Medicine and Gastroenterology Research Unit, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: David T
authors.initials: DT
authors.lastname: Asuzu
authors.affiliation: Center for Individualized Medicine and Gastroenterology Research Unit, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: Sabriya A
authors.initials: SA
authors.lastname: Syed
authors.affiliation: Center for Individualized Medicine and Gastroenterology Research Unit, Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: Tamas
authors.initials: T
authors.lastname: Ordog
authors.affiliation: Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Paul-Ehrlich-Strasse 42-44, Frankfurt, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Zörnig
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D053477:Apoptotic Protease-Activating Factor 1 / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D002460:Cell Line; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics*; D015870:Gene Expression / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D056885:Interstitial Cells of Cajal / Q000378:metabolism; D008667:Metalloproteins; D051379:Mice; D016688:Mice, Inbred NOD; D008819:Mice, Nude; D016513:Mice, SCID; D008928:Mitochondria / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D015027:Zebrafish / Q000235:genetics
chemical_list: C506592:APAF1 protein, human; D053477:Apoptotic Protease-Activating Factor 1; C574944:CIAO2A protein, human; D002352:Carrier Proteins; D008667:Metalloproteins; D025521:Tumor Suppressor Proteins
keywords: FAM96A; GIST; ICC; apoptosis; tumor suppressor