Aromatase expression in oral mucosa and squamous cell carcinoma

Abstract

Aromatase is a cytochrome P-450 enzyme that catalyzes the conversion of androgens to estrogens. It has been found to be expressed not only in the ovaries and testes but also in extragonadal tissues such as skin, muscle, fat, bone, and brain, contributing to the local estrogen formation in these tissues. Its increased expression in breast carcinomas makes it a promising target of chemointervention for hormonal-responsive breast carcinomas. Aromatase expression has never been investigated in normal oral mucosa or in squamous cell carcinomas. Using Western blot and a commercially available aromatase antibody, we found 2 immunoreactive bands of 53 and 60 kDa in dispase-separated oral epithelium obtained from crown-lengthening procedures. The 2 bands were also detected in the primary culture of normal oral epithelial cells (NOEC) from different individuals as well as an oral squamous cell carcinoma (SCC) cell line. However, in NOEC the 60 kDa band was considerably more prominent, while in SCC the 53 kDa was more predominant. Our results indicate that normal oral epithelial cells as well as oral squamous cell carcinoma have the ability to synthesize estrogen. Further immunohistochemical and RT-PCR studies are in progress. Aromatase is a cytochrome P-450 enzyme that catalyzes the conversion of androgens to estrogens. It has been found to be expressed not only in the ovaries and testes but also in extragonadal tissues such as skin, muscle, fat, bone, and brain, contributing to the local estrogen formation in these tissues. Its increased expression in breast carcinomas makes it a promising target of chemointervention for hormonal-responsive breast carcinomas. Aromatase expression has never been investigated in normal oral mucosa or in squamous cell carcinomas. Using Western blot and a commercially available aromatase antibody, we found 2 immunoreactive bands of 53 and 60 kDa in dispase-separated oral epithelium obtained from crown-lengthening procedures. The 2 bands were also detected in the primary culture of normal oral epithelial cells (NOEC) from different individuals as well as an oral squamous cell carcinoma (SCC) cell line. However, in NOEC the 60 kDa band was considerably more prominent, while in SCC the 53 kDa was more predominant. Our results indicate that normal oral epithelial cells as well as oral squamous cell carcinoma have the ability to synthesize estrogen. Further immunohistochemical and RT-PCR studies are in progress.