Abstract
This study aimed to evaluate the expression of the complex APC, GSK-3β, Axine and β-Catenin, which are components from canonical Wnt signaling pathway during chemically induced oral carcinogenesis by 4-nitroquinoline 1-oxide in rats. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO via drinking water, during 4, 12 and 20 weeks. A total of 10 animals were used as controls. No histopathological changes were noticed to control group and that exposed to 4NQO during 4 weeks. The animals exposed to 4NQO for 12 and 20 weeks pointed out leukoplakia, exophytic and ulcerated lesions, as well as hyperplasia and hyperkeratosis with epithelial dysplasia and squamous cell carcinoma of well differentiated type, respectively. A high immunopositivity for APC and axine was noticed to experimental groups exposed to 4NQO during 12 and 20 weeks, when compared to negative control. Nevertheless, β-catenin pointed out an up-regulation in pre-neoplastic lesions and oral squamous cell carcinomas. GSK-3β did not show remarkable changes along a time course experiment. Taken together, a downregulation of APC and Axine as well as an up-regulation of β-catenin play a crucial role during oral cancer progression in rats.
