title: Gene expression profiles modulated by the human carcinogen aristolochic acid I in human cancer cells and their dependence on TP53.
abstract: Aristolochic acid (AA) is the causative agent of urothelial tumours associated with aristolochic acid nephropathy. These tumours contain TP53 mutations and over-express TP53. We compared transcriptional and translational responses of two isogenic HCT116 cell lines, one expressing TP53 (p53-WT) and the other with this gene knocked out (p53-null), to treatment with aristolochic acid I (AAI) (50-100 microM) for 6-48 h. Modulation of 118 genes was observed in p53-WT cells and 123 genes in p53-null cells. Some genes, including INSIG1, EGR1, CAV1, LCN2 and CCNG1, were differentially expressed in the two cell lines. CDKN1A was selectively up-regulated in p53-WT cells, leading to accumulation of TP53 and CDKN1A. Apoptotic signalling, measured by caspase-3 and -7 activity, was TP53-dependent. Both cell types accumulated in S phase, suggesting that AAI-DNA adducts interfere with DNA replication, independently of TP53 status. The oncogene MYC, frequently over-expressed in urothelial tumours, was up-regulated by AAI, whereas FOS was down-regulated. Observed modulation of genes involved in endocytosis, e.g. RAB5A, may be relevant to the known inhibition of receptor-mediated endocytosis, an early sign of AA-mediated proximal tubule injury. AAI-DNA adduct formation was significantly greater in p53-WT cells than in p53-null cells. Collectively, phenotypic anchoring of the AAI-induced expression profiles to DNA adduct formation, cell-cycle parameters, TP53 expression and apoptosis identified several genes linked to these biological outcomes, some of which are TP53-dependent. These results strengthen the importance of TP53 in AA-induced cancer, and indicate that other alterations, e.g. to MYC oncogenic pathways, may also contribute.
authors.affiliation: Section of Molecular Carcinogenesis, Institute of Cancer Research, Brookes Lawley Building, Sutton, Surrey, UK.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Simões
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Hockley
authors.forename: Tanja
authors.initials: T
authors.lastname: Schwerdtle
authors.forename: Gonçalo
authors.initials: G
authors.lastname: Gamboa da Costa
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Schmeiser
authors.forename: David H
authors.initials: DH
authors.lastname: Phillips
authors.forename: Volker M
authors.initials: VM
authors.lastname: Arlt
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D034341:Aristolochic Acids / Q000633:toxicity*; D015153:Blotting, Western; D002273:Carcinogens / Q000633:toxicity*; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016000:Cluster Analysis; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018736:DNA Adducts; D053960:DNA Breaks; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D017353:Gene Deletion; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D045325:HCT116 Cells; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D034341:Aristolochic Acids; D002273:Carcinogens; D018736:DNA Adducts; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C000228:aristolochic acid I