Role of microRNAs in gynecological pathology.

microRNAs (miRNAs) are 21-22 nucleotide non-coding RNAs that regulate gene expression and play fundamental roles in biological processes. These small molecules bind to target mRNAs, leading to translational repression and/or mRNA degradation. Aberrant miRNA expression is associated with several human diseases such as cancer, cardiovascular disorders, inflammatory diseases and gynecological pathology. The present article reviews the role of miRNAs in four gynecological disorders that affect the ovary or the uterus, one benign and frequent disease (endometriosis) that is classified as a tumor-like lesion and three malignant gynecological diseases (endometrial, cervical and ovarian cancers). Endometriosis, defined as the presence of endometrium outside the uterus, is one of the most frequent benign gynecological diseases. Similarly to tumor metastasis, endometriotic implants require neovascularization to proliferate, invade the extracellular matrix and establish an endometriotic lesion. Despite its high prevalence and incapacitating symptoms, the exact pathogenic mechanism of endometriosis remains unsolved. A relationship between endometriosis and gynecological cancer, especially ovarian cancer, has been reported. Endometriosis is a multifactorial and polygenic disease, and emerging data provide evidence that a dysregulation of miRNA expression may be involved. miRNAs appear to be potent regulators of gene expression in endometriosis, raising the prospect of using miRNAs as biomarkers and therapeutic tools in this disease. In cancer, miRNAs have an important role as regulatory molecules, acting as oncogenes (oncomiRs) or tumor suppressors. Endometrial cancer is one of the most frequent gynecological malignancies in the developed countries. Cervical cancer, also one of the most common cancers in women, is associated with high-risk human papillomaviruses although this infection alone may not be enough to induce the malignant transformation. Ovarian cancer is the fifth leading cause of all cancer-related deaths among women. Over 80% of cases are diagnosed at an advanced stage, with a reduced five-year survival rate. Recent studies have shown that miRNAs are aberrantly expressed in different human cancer types, including endometrial, cervical and ovarian cancer, and that specific dysregulated miRNAs may act as biomarkers of patients' outcome. Recently, miRNAs have been detected in serum and plasma, and circulating miRNA expression profiles have now been associated with a range of different tumor types. Their accessibility in peripheral blood and stability given the fact that miRNAs circulate confined within exosomes, make researchers foster hope in their role as emerging biomarkers of cancer and other disorders. The development of therapies that might block the expression or mimic the functions of miRNAs could represent new therapeutic strategies for any of the aforementioned gynecological disorders.

Influence of peritoneal fluid on the expression of angiogenic and proteolytic factors in cultures of endometrial cells from women with endometriosis.

BACKGROUND: Endometriosis, defined as the presence of endometrium outside the uterus, is one of the most frequent benign gynaecological diseases. It has been suggested that both endometrial and peritoneal factors, related to angiogenesis and proteolysis, can be implicated in this disease. The aim of this study was to evaluate the influence of peritoneal fluid on the expression of angiogenic and proteolytic factors in cultures of endometrial cells from women with and without endometriosis. METHODS: Endometrial cells were isolated, cultured and treated with endometriotic or normal peritoneal fluid. Vascular endothelial growth factor-A (VEGF-A), urokinase plasminogen activator (uPA), matrix metalloproteinase-3 (MMP-3) and their inhibitors including thrombospondin-1, plasminogen activator inhibitor-1 and MMP inhibitor type 1 (TIMP-1) mRNA levels were evaluated by quantitative RT-PCR, and protein levels were quantified by ELISA. RESULTS: Peritoneal fluid from women with endometriosis induced an increase in VEGF-A and uPA protein and VEGF-A mRNA and uPA mRNA levels in endometrial cell culture from women with (P < 0.01) and without endometriosis (P < 0.05). The highest levels of VEGF-A and uPA were observed in endometrial cell cultures from patients with endometriosis and treated with peritoneal fluid from women with endometriosis. CONCLUSIONS: Peritoneal fluid from women with endometriosis induced more VEGF and uPA expression in endometrial cell culture from women with endometriosis than did normal peritoneal fluid. Endometrial-peritoneal interactions increased angiogenic and proteolytic factors in endometrial cells, which could contribute to the development of endometriotic lesions.