Expression of sfrp1 and activation of the Wnt pathway in the adrenal glands of healthy ferrets and neutered ferrets with hyperadrenocorticism

Gonadectomy induces the pathogenesis of luteinising hormone receptor positive, androgen and oestrogen producing tumours in the adrenal cortex of ferrets. In mice, the castration-dependent appearance of adrenocortical tumours has been attributed to loss of expression of the tumour suppressor gene Secreted Frizzled Related Protein 1 (sfrp1), a dominant inhibitor of the Wnt pathway, which controls cell proliferation and ‘cell faith’ decisions. This study investigated whether sfrp1 and the Wnt pathway play a similar role in the pathogenesis of hyperadrenocorticism in ferrets. The expression of sfrp1 and three target genes of the Wnt pathway (c-myc, axin2 and cyclinD1) in seven adrenal glands from healthy ferrets and in 13 adrenocortical tumours were studied by quantitative real-time PCR. Nuclear β-catenin staining was assessed by immunohistochemistry. Sfrp1 mRNA expression was up-regulated and axin2 and cyclinD1 were down-regulated in the tumour group in comparison with the control group. Decreased nuclear β-catenin staining supported the decrease in active Wnt signalling in adrenocortical tumours in ferrets. Therefore, it is unlikely that the involvement of sfrp1 and the Wnt pathway in the pathogenesis of adrenocortical tumours in ferrets is similar to that described in mice.