Doris M. Benbrook^1,2, Stan Lightfoot³, James Ranger-Moore⁴, Tongzu Liu¹, Shylet Chengedza², William L. Berry⁵ and Igor Dozmorov⁶

¹Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK. ²Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK. ³Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK. ⁴Arizona Cancer Center, AZ. ⁵Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK. 6Oklahoma Medical Research Foundation, Oklahoma City, OK.

Abstract

An organotypic model of endometrial carcinogenesis and chemoprevention was developed in which normal endometrial organotypic cultures exposed to the carcinogen, DMBA (7,12-dimethylbenz[a]anthracene), developed a cancerous phenotype in the absence, but not presence of subsequent treatment with a fl exible heteroarotinoid (Flex-Het), called SHetA2. A discriminant function based on karyometric features of cellular nuclei and an agar clonogenic assay confirmed these histologic changes. Interpretation of microarray data using an internal standard approach identified major pathways associated with carcinogenesis and chemoprevention governed by c-myc, p53, TNFα and Jun genes. Cluster analysis of functional associations of hypervariable genes demonstrated that carcinogenesis is accompanied by a stimulating association between a module of genes that includes tumor necrosis factor α (TNFα), c-myc, and epidermal growth factor-receptor (EGF-R) and a module that includes insulin-like growth factor I-receptor (IGF-IR), p53, and Jun genes. Two secreted proteins involved in these systems, tenascin C and inhibin A, were validated at the protein level. Tenascin C is an EGF-R ligand, and therefore may contribute to the increased EGF-R involvement in carcinogenesis. The known roles of the identifi ed molecular systems in DMBA and endometrial carcinogenesis and chemoprevention supports the validity of this model and the potential clinical utility of SHetA2 in chemoprevention.