title: Recurrent MLK4 Loss-of-Function Mutations Suppress JNK Signaling to Promote Colon Tumorigenesis.
abstract: MLK4 is a member of the mixed-lineage family of kinases that regulate the JNK, p38, and ERK kinase signaling pathways. MLK4 mutations have been identified in various human cancers, including frequently in colorectal cancer, where their function and pathobiological importance have been uncertain. In this study, we assessed the functional consequences of MLK4 mutations in colon tumorigenesis. Biochemical data indicated that a majority of MLK4 mutations are loss-of-function (LOF) mutations that can exert dominant-negative effects. In seeking to understand the abrogated activity of these mutants, we elucidated a new MLK4 catalytic domain structure. To determine whether MLK4 is required to maintain tumorigenic phenotypes, we reconstituted its signaling axis in colon cancer cells harboring MLK4-inactivating mutations. We found that restoring MLK4 activity reduced cell viability, proliferation, and colony formation in vitro and delayed tumor growth in vivo. Mechanistic investigations established that restoring the function of MLK4 selectively induced the JNK pathway and its downstream targets, cJUN, ATF3, and the cyclin-dependent kinase inhibitors CDKN1A and CDKN2B. Our work indicates that MLK4 is a novel tumor-suppressing kinase harboring frequent LOF mutations that lead to diminished signaling in the JNK pathway and enhanced proliferation in colon cancer.
authors.affiliation: Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Marusiak
authors.affiliation: Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Natalie L
authors.initials: NL
authors.lastname: Stephenson
authors.affiliation: Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Hayeon
authors.initials: H
authors.lastname: Baik
authors.affiliation: Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Eleanor W
authors.initials: EW
authors.lastname: Trotter
authors.affiliation: Computational Biology Support, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Yaoyong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Colorectal Cancer and Wnt Signalling Group, The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
authors.forename: Karen
authors.initials: K
authors.lastname: Blyth
authors.affiliation: Colorectal Cancer and Wnt Signalling Group, The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
authors.forename: Susan
authors.initials: S
authors.lastname: Mason
authors.affiliation: Computational Biology Support, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Phil
authors.initials: P
authors.lastname: Chapman
authors.affiliation: Salk Institute for Biological Studies, La Jolla, California.
authors.forename: Lorena A
authors.initials: LA
authors.lastname: Puto
authors.affiliation: Discovery Sciences, AstraZeneca, Cambridge, United Kingdom.
authors.forename: Jon A
authors.initials: JA
authors.lastname: Read
authors.affiliation: Discovery Sciences, AstraZeneca, Cheshire, United Kingdom.
authors.forename: Claire
authors.initials: C
authors.lastname: Brassington
authors.affiliation: Discovery Sciences, AstraZeneca, Cheshire, United Kingdom.
authors.forename: Hannah K
authors.initials: HK
authors.lastname: Pollard
authors.affiliation: Discovery Sciences, AstraZeneca, Cambridge, United Kingdom.
authors.forename: Chris
authors.initials: C
authors.lastname: Phillips
authors.affiliation: Discovery Sciences, AstraZeneca, Cheshire, United Kingdom.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Green
authors.affiliation: Discovery Sciences, AstraZeneca, Cheshire, United Kingdom.
authors.forename: Ross
authors.initials: R
authors.lastname: Overman
authors.affiliation: Discovery Sciences, AstraZeneca, Cheshire, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Collier
authors.affiliation: Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Testoni
authors.affiliation: Computational Biology Support, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom. RNA Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom.
authors.forename: Crispin J
authors.initials: CJ
authors.lastname: Miller
authors.affiliation: Salk Institute for Biological Studies, La Jolla, California.
authors.forename: Tony
authors.initials: T
authors.lastname: Hunter
authors.affiliation: Colorectal Cancer and Wnt Signalling Group, The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
authors.forename: Owen J
authors.initials: OJ
authors.lastname: Sansom
authors.affiliation: Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom. John.Brognard@cruk.manchester.ac.uk.
authors.forename: John
authors.initials: J
authors.lastname: Brognard
mesh_terms: D000818:Animals; D063646:Carcinogenesis; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000235:genetics* / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009154:Mutation; D015398:Signal Transduction; D023041:Xenograft Model Antitumor Assays
chemical_list: D020930:MAP Kinase Kinase Kinases; C582627:MAP3K21 protein, human