Overexpression of aldose reductase in human cancer tissues

Background: Aldose reductase (AR) belongs to the aldo-keto reductase (AKR) Super family and catalyzes the conversion of aldoses to the corresponding alcohol. Some recent studies have shown overexpression of AR and AR-like proteins in human liver cancers and some cancer cell lines Such as HepG2 and HeLa cells. However, apart from hepatic cancer tissue, the status of AR expression has not been reported in other human cancer tissues. Therefore, in this preliminary report, the expression of AR in a few other commonly occurring cancer tissues was investigated. Material/Methods: Fresh post-surgical tumor tissues of breast, ovary, cervix, and rectum were collected from subjects who were admitted for surgical therapy of tumors. Tumor area and tumor characteristics were determined by histopathological analysis. The expression and activity of AR in tumor and non-tumor areas was carried Out by immunohistochemical, immunoblotting, and enzyme activity studies. Results: Immunoblotting results indicated overexpression of AR in breast, ovarian, cervical, and rectal cancerous tissues. Furthermore, biochemical data revealed that the specific activity of AR was higher in tumor areas than in non-tumor regions of these tissues. The overexpression of AR in tumor tissue was further validated by immunohistochemistry in the case of breast tissue. Conclusions: These preliminary results Suggest overexpression and increased activity of AR in different human cancers. However, the incidence of AR overexpression and its role in drug resistance needs to be established with a large number of samples of various cancers.