title: Reduced HRAS G12V-Driven Tumorigenesis of Cell Lines Expressing KRAS C118S.
abstract: In many different human cancers, one of the HRAS, NRAS, or KRAS genes in the RAS family of small GTPases acquires an oncogenic mutation that renders the encoded protein constitutively GTP-bound and thereby active, which is well established to promote tumorigenesis. In addition to oncogenic mutations, accumulating evidence suggests that the wild-type isoforms may also be activated and contribute to oncogenic RAS-driven tumorigenesis. In this regard, redox-dependent reactions with cysteine 118 (C118) have been found to promote activation of wild-type HRAS and NRAS. We sought to determine if this residue is also important for the activation of wild-type KRAS and promotion of tumorigenesis. Thus, we mutated C118 to serine (C118S) in wild-type KRAS to block redox-dependent reactions at this site. We now report that this mutation reduced the level of GTP-bound KRAS and impaired RAS signaling stimulated by the growth factor EGF. With regards to tumorigenesis, we also report that oncogenic HRAS-transformed human cells in which endogenous KRAS was knocked down and replaced with KRASC118S exhibited reduced xenograft tumor growth, as did oncogenic HRAS-transformed KrasC118S/C118S murine cells in which the C118S mutation was knocked into the endogenous Kras gene. Taken together, these data suggest a role for redox-dependent activation of wild-type KRAS through C118 in oncogenic HRAS-driven tumorigenesis.
authors.affiliation: Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Lu
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America; Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Counter
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000473:pathology; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D055879:Gene Knock-In Techniques; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010084:Oxidation-Reduction; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics* / Q000378:metabolism; D012694:Serine / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D014183:Transplantation, Heterologous
chemical_list: C117307:KRAS protein, human; D008565:Membrane Proteins; D012694:Serine; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D003545:Cysteine