Endometrial fluid is a specific and non-invasive biological sample for protein biomarker identification in endometriosis.

BACKGROUND: The development of non-invasive diagnostic methods for endometriosis requires sensitive and disease specific biomarkers. Here, we describe the use of aspirated endometrial fluid from women with and without endometriosis as a novel biological sample for biomarker discovery. METHODS: Differential protein expression profiling of aspirates from women with early endometriosis (n = 14), advanced endometriosis (n = 32) and without evidence of the disease (n = 32) was assessed by two-dimensional gel electrophoresis (2-DE). A biomarker validation study was performed in an independent cohort (early endometriosis n = 6 and advanced endometriosis n = 14, controls n = 15). RESULTS: The analysis resulted in the identification of 31 proteins showing statistically significant differences in expression. The proteins identified are related to cell signalling, cell death and cell movement, processes that may be involved in the onset and/or progression of endometriosis. The differences in expression observed for 14-3-3 (signal transduction) and moesin (cytoskeletal structure) were confirmed in an independent group of endometriosis patients. CONCLUSIONS: Endometrial fluid represents a novel sample for proteomic analysis offering reliable, disease specific information on protein expression, facilitating the discovery of biomarkers for endometriosis. The results described here complement previous proteomic studies, providing new endometriosis-related proteins to be validated as diagnostic markers.

Implication of human N-alpha-acetyltransferase 5 in cellular proliferation and carcinogenesis.

The N-alpha-acetyltransferase NatB, composed in Saccharomyces cerevisiae by the Nat3p and Mdm20p subunits, is an important factor for yeast growth and resistance to several stress agents. However, the expression and functional role of the mammalian counterpart has not yet been analysed. Here, we report the identification of Nat3p human homologue (hNAT5/hNAT3) and the characterization of its biological function. We found that hNAT5/hNAT3 silencing in HeLa cells results in inhibition of cell proliferation and increased sensitivity to the pro-apoptotic agent MG132. Moreover, inhibition of hNAT5/hNAT3 expression induces p53 activation and upregulation of the antiproliferative protein p21(WAF1/CIP1). The changes of the cellular transcriptome after hNAT5/hNAT3 knockdown confirmed the involvement of this protein in cell growth and survival processes. Among the genes differentially expressed, we observed upregulation of several p53-dependent antiproliferative and pro-apoptotic genes. In the c-myc transgenic mice, which is a model of inducible hepatocarcinoma, we found that hNAT5/hNAT3 was upregulated when the tumour was induced. In accordance with this observation, we noticed increased hNAT5/hNAT3 protein level in neoplastic versus non-neoplastic tissue in a high proportion of patients with hepatocellular carcinoma. Consequently, our results suggest that hNAT5/hNAT3 is required for cellular proliferation and can be implicated in tumour growth.