Aim: Fatty acid metabolism of the endometrium is important for tissue homeostasis in the proliferative and secretory phase of the menstrual cycle. The enzyme acyl-CoA synthetase 5 (ACS5) plays a crucial role in fatty acid metabolism, mainly through the generation of multifunctional long-chain-fatty-acid-CoA esters. The aim of the present study was to characterize expression and localization of ACS5 in the normal human endometrium and in endometrioid adenocarcinomas.
Methods and results: Expression of ACS5 in the human endometrium was investigated by in situ techniques (immunohistochemistry, mRNA in situ hybridization) and a molecular approach (reverse transcriptase-polymerase chain reaction, Western blot). ACS5 protein and mRNA were localized to the epithelium of the human endometrium. Here, ACS5 expression was found throughout the menstrual cycle as well as in the postmenopausal endometrium. Notably, in endometrioid adenocarcinomas, the ACS5 molecule was found abundantly in well-differentiated tumours, but not in poorly differentiated adenocarcinomas.
Conclusions: The abundance of ACS5 in the endometrial epithelium throughout the menstrual cycle provides support for its role in the regulation of tissue homeostasis. With regard to its value for histopathological diagnosis, immunohistochemical characterization of endometrioid adenocarcinomas shows that a decrease in ACS5 expression correlates with tumour dedifferentiation.