Prof Roland Wolf OBE

The aim of this group is to understand the function and regulation of genes which determine the sensitivity of cells to therapeutic drugs and environmental agents. This is important in view of the unequivocal role of environmental factors in the pathogenesis of human disease and because the same families of genes can determine both the beneficial and adverse effects of drugs. In addition, there is now considerable evidence that these proteins have the capacity to generate drug resistance in cancer chemotherapy. Individuality in the expression of these proteins can therefore be a significant factor in both disease susceptibility and the outcome of drug therapy. Some of this individuality is genetically determined and the study of this genetic variability is currently known as pharmacogenetics. Work within the group addresses both fundamental and applied questions associated with the function of these genes and has a fundamental interest in cancer aetiology and drug development and use. A wide range of pharmacological, molecular and genetic approaches are applied in this work including the generation of transgenic models. Research projects include: 1) Genetic factors which determine clinical response to anticancer drug treatment. 2) Molecular biology, genetics and functions of the mammalian cytochrome P450 system. 3) Genetic and environmental factors involved in the aetiology of colon cancer. 4) Application of transgenic approaches to study gene-environment interactions. 5) Role of oxidative stress genes in cancer aetiology and treatment.

Current research projects under these themes include:

Structural and functional analysis of the cytochrome P450 system

These enzymes play a pivotal role in determining the metabolic fate of environmental chemicals and drugs. Cytochrome P450s are membrane-bound terminal electron acceptors from cytochrome P450 reductase and catalyse the insertion of one atom of molecular oxygen into the substrate. In most cases this increases hydrophilicity and facilitates elimination. However, such reactions can also be the mechanism of pro-drug activation or can increase the reactivity of the chemical concerned, leading to toxicity and mutation. This is the initial step in chemical carcinogenesis. In this programme, which is a close collaboration with Professor Gordon Roberts in Leicester, we are carrying out a combination of molecular modelling, NMR and site directed mutagenesis studies to predict the topology of the active site of the major enzymes involved in drug metabolism in man. Part of this programme involves significant support from the pharmaceutical industry, as one aim is to develop models which will predict how drugs are metabolised in man.

Transgenics Programme

Much can be learned about the function of proteins in vitro, however the function and regulation of proteins involved in adaptive responses to toxins is complex and an in vivo approach to understanding the function of specific genes is essential. The aim of this programme, directed by Dr Colin Henderson (see also Dr Henderson's project description), is to either delete specific genes from the mouse genome or to introduce the promoters of human genes into mice or rats so that the mechanism of regulation in vivo can be established. In addition, the often profound species differences in chemical response can be attributed to structural and functional differences in receptors and transcription factors which mediate these responses. In order to understand the function of these proteins, transgenic models are being developed where the genes encoding the human proteins are expressed and linked to suitable reporter systems. A focus of our current studies in this area is to establish the role of specific genes in determining cellular sensitivity to anticancer drugs.

Pharmacogenetics/Disease Susceptibility

We are interested in how genetic and phenotypic variability in the regulation and function of specific genes alters both drug response and disease susceptibility. Many of the genes involved in drug absorption, metabolism and response (i.e. drug targets) are polymorphic and for a number of years we have been identifying novel polymorphisms in these gene families and studying their relationship to adverse drug reactions and disease susceptibility. In addition, we have established a mutation detection facility so that tumour mutation spectra and pharmacogenetic polymorphisms in cancer patients can be studied simultaneously to gain further insight into disease aetiology and pathogenesis. Current projects in pharmacogenetics include: Genetic and phenotypic factors which determine the outcome of the treatment of skin disorders with Dr Sally Ibbotson; Genetic factors in variability in response to antidepressant drugs with Professor Ian Reid; The interaction between diet and genetic factors in the pathogenesis of colon cancer and, most recently, in a collaboration with Professor Elaine Rankin and Professor Sir David Lane, individuality in response to cancer chemotherapy.

References

1. Wolf, C.R and Smith, G. Pharmacogenetics. In Poste, G., Bell, J., Davies, K., Goodfellow, P. and Hastie, N. (eds.): British Medical Bulletin 5, pp 366-386 (1999).
2. Henderson, C.J., Wolf, C.R., Kitteringham, N., Powell, H., Otto, D. and Park, B.K. Increased resistance to paracetamol hepatotoxicity in mice lacking glutathione S-transferase pi. Proc. Natl. Acad. Sci. USA 97, 12741-12745 (2000).
3. Smith, G., Carey, F.A., Beattie, J., Wilkie, M.J.V., Lightfoot, T.J., Coxhead, J., Garner, R.C., Steele, R.J.C., Wolf, C.R. Mutations in APC, Kirsten-ras and p53 – alternative genetic pathways to colorectal cancer. Proc. Natl. Acad. Sci. USA 99, 9433-9438 (2002).
4. Henderson, C.J., Otto, D.M.E., Carrie, D., Magnuson, M.A., McLaren, A.W., Rosewell, I. and Wolf, C.R. Inactivation of the hepatic cytochrome P450 system by conditional deletion of hepatic cytochrome P450 reductase. J. Biol. Chem. 278, 13480-13486 (2003).
5. Rencurel, F., Stenhouse, A., Hawley, S.A., Friedberg, T., Hardie, D.G., Sutherland, C. and Wolf, C.R. AMP-activated protein kinase mediates phenobarbital induction of CYP2B gene expression in hepatocytes and a newly derived human hepatoma cell line. J. Biol. Chem. 280, 4367-4373 (2005).
6. Pass, G.J., Carrie, D., Boylan, M., Lorimore, S., Wright, E., Houston, B., Henderson, C.J. and Wolf, C.R. Role of hepatic cytochrome P450s in the pharmacokinetics and toxicity of cyclophosphamide: studies using the hepatic cytochrome P450 reductase null mouse. Cancer Res. 65, 4211-4217 (2005).
7. McLaughlin, L.A., Paine, M.J.I., Kemp, C.A., Marechal, J-D., Flanagan, J.U., Ward, C.J., Sufcliffe, M.J., Roberts, G.C.K. and Wolf, C.R. Why is quinidine an inhibitor of cytochrome P450 2D6? The role of key active-site residues in quinidine binding. J. Biol. Chem. 280, 38617-38624 (2005).
8. Wang, X.J., Hayes, J.D. and Wolf, C.R. Generation of a stable antioxidant response element-driven reporter gene cell line and its use to demonstrate redox-dependent activation of Nrf2 (NF-E2 p45-related factor 2) by cancer chemotherapeutic agents. Cancer Res. 22, 10983-10994 (2006).
9. Ritchie, K.J., Henderson, C.J., Wang, X. J., Vassieva, O., Carrie, D., Farmer, P.B., Gaskell, M., Park, K. and Wolf, C.R. Glutathione transferase Pi plays a critical role in the development of lung carcinogenesis following exposure to tobacco-related carcinogens and urethane. Cancer Res. 67, 9248-9257 (2007).
10. Wang, X. J., Hayes, J.D., Henderson, C.J. and Wolf, C.R. Identification of retinoic acid as an inhibitor of transcription factor Nrf2 through activaton of retinoic acid receptor alpha. Proc. Natl. Acad. Sci. USA 104, 19589-19594 (2007).