Loss of VHL in RCC Reduces Repair and Alters Cellular Response to Benzo[a]pyrene

M.A.C. Schults, Y. Oligschlaeger, R.W. Godschalk, F.J. van Schooten, R.K. Chiu

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Mutations of the von Hippel-Lindau (VHL) tumor suppressor gene occur in the majority of sporadic renal-cell carcinomas (RCC). Loss of VHL function is associated with stabilization of hypoxia-inducible factor alpha (HIFalpha). We and others demonstrated that there is a two-way interaction between the aryl hydrocarbon receptor, which is an important mediator in the metabolic activation and detoxification of carcinogens, and the HIF1-pathway leading to an increased genetic instability when both pathways are simultaneously activated. The aim of this study was to investigate how environmental carcinogens, such as benzo[a]pyrene (BaP), which can be metabolically activated to BaP-7,8-diOH-9,10-epoxide (BPDE) play a role in the etiology of RCC. We exposed VHL-deficient RCC4 cells, in which HIFalpha is stabilized regardless of oxygen tension, to 0.1 muM BaP for 18 h. The mutagenic BPDE-DNA adduct levels were increased in HIFalpha stabilized cells. Using qRT-PCR, we demonstrated that absence of VHL significantly induced the mRNA levels of AhR downstream target CYP1A1. Furthermore, HPLC analysis indicated that loss of VHL increased the concentration of BaP-7,8-dihydroxydiol, the pre-cursor metabolite of BPDE. Interestingly, the capacity to repair BPDE-DNA adducts in the HIFalpha stabilized RCC4 cells, was markedly reduced. Taken together, these data indicate that loss of VHL affects BaP-mediated genotoxic responses in RCC and decreases repair capacity.
Original languageEnglish
Pages (from-to)270
JournalFrontiers in Oncology
Publication statusPublished - 1 Jan 2013

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