1) To assess the role of genetically-determined variability of sulfotransferase (ST) expression in susceptibility to cancer induced by environmental agents.
2) To investigate the incidence of polymorphic expression of phenol sulfotransferase (PST) in the following groups : a) individuals who have contracted bladder cancer as a result of documented and characterised exposure to aromatic amines; b) individuals who have documented exposure to aromatic amines but who failed to develop bladder cancer; c) individuals with cancer of the colon (where aromatic amines in the diet are suspected to play a significant role); and d) a group of healthy volunteers. High levels of expression of PST may result in increased susceptibility to carcinogenesis following exposure to these compounds, since they are bioactivated by STs.
3) To study the molecular basis for the human phenol sulfotransferase polymorphism.
4) To develop a simple diagnostic test, ideally based on the polymerase chain reaction, for the human phenol sulfotransferase polymorphism.
Exposure to chemicals present in the environment, in the broadest sense, is one of the major causes of human cancer. The ability to predict those at genetic risk from chemical-induced cancers would have a major impact on the incidence of these diseases. Such an ambitious goal can only be achieved through a thorough understanding of the processes whereby exposure to environmental chemicals results in the molecular and cellular changes associated with carcinogenesis. This proposal focusses on an enzyme system - sulfotransferase (ST) - which is known to bioactivate certain environmental procarcinogens, resulting in the formation of highly reactive species which are capable of adducting to DNA. The isoenzyme of ST, as this is a multi-gene family, which is principally responsible for these bioactivation reactions, particularly with aromatic amines, is subject to polymorphic expression in the human population. We therefore propose to investigate this polymorphic variation in ST expression in individuals who have developed cancer as a result of exposure to environmental chemicals.
We have chosen to study two groups of individuals, one very well defined group who have had documented exposure to aromatic amines, some of whom have developed cancer of the urinary bladder, and a second group of individuals who have cancer of the colon, where ingestion of aromatic amines from the diet (particularly cooked meats) is suggested to be involved in the pathogenesis of the disease. Our studies will type these individuals for the ST polymorphism and determine the relationship between the expression of the enzyme and susceptibility to cancer.
Further to this, and to enable such studies to become more widely applicable, we aim to determine the molecular basis of this polymorphism, and to develop a simple method(s) to determine sulfator status of individuals using the polymorase chain reaction (PCR).
The programme will lead to enhanced appreciation of the role of bioactivation of chemicals by this route and increased understanding of the molecular basis of susceptibility to chemical-induced cancer.
Funding SchemeCSC - Cost-sharing contracts
DD1 9SY Dundee