title: VHL missense mutations in the p53 binding domain show different effects on p53 signaling and HIFα degradation in clear cell renal cell carcinoma.
abstract: Clear cell Renal Cell Carcinoma (ccRCC) formation is connected to functional loss of the von Hippel-Lindau (VHL) gene. Recent data identified its gene product, pVHL, as a multifunctional adaptor protein which interacts with HIFα subunits but also with the tumor suppressor p53. p53 is hardly expressed and rarely mutated in most ccRCC. We showed that low and absent p53 expression correlated with the severity of VHL mutations in 262 analyzed ccRCC tissues. In contrast to nonsense and frameshift mutations which abrogate virtually all pVHL functions, missense mutations may rather influence one or few functions. Therefore, we focused on four VHL missense mutations, which affect the overlapping pVHL binding sites of p53 and Elongin C, by investigating their impact on HIFα degradation, p53 expression and signaling, as well as on cellular behavior using ccRCC cell lines and tissues. TP53 mRNA and its effector targets p21, Bax and Noxa, were altered both in engineered cell lines and in tumor tissues which carried the same missense mutations. Two of these mutations were not able to degrade HIFα whereas the remaining two mutations led to HIFα downregulation, suggesting the latter are p53 binding site-specific. The selected VHL missense mutations further enhanced tumor cell survival, but had no effects on cell proliferation. Whereas Sunitinib was able to efficiently reduce cell proliferation, Camptothecin was additionally able to increase apoptotic activity of the tumor cells. It is concluded that systematic characterization of the VHL mutation status may help optimizing targeted therapy for patients with metastatic ccRCC.
authors.affiliation: Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Caroline Fanja
authors.initials: CF
authors.lastname: Razafinjatovo
authors.affiliation: Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Stiehl
authors.affiliation: Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Eva
authors.initials: E
authors.lastname: Deininger
authors.affiliation: Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Rechsteiner
authors.affiliation: Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Holger
authors.initials: H
authors.lastname: Moch
authors.affiliation: Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Schraml
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002166:Camptothecin / Q000494:pharmacology; D002292:Carcinoma, Renal Cell / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D000075065:Elongin / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D007680:Kidney Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D020125:Mutation, Missense; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D059748:Proteolysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D000077210:Sunitinib; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C494826:BAX protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C000616395:ELOC protein, human; D000075065:Elongin; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007211:Indoles; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D011758:Pyrroles; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C497446:VHL protein, human; D000077210:Sunitinib; D002166:Camptothecin
keywords: HIFα; VHL missense mutations; clear cell renal cell carcinoma; p53; pVHL binding sites