Biparental expression of ESX1L gene in placentas from normal and intrauterine growth-restricted pregnancies

Equivalent levels of X-linked gene products between males and females are reached by means of X chromosome inactivation (XCI). In the human and murine embryonic tissues, both the paternally and maternally derived X chromosomes (X P and X M) may be inactivated. In murine extra-embryonic tissues, X P is imprinted and always silenced; humans, unlike mice, can inactivate the X M in extra-embryonic lineages without an adverse outcome. This difference is probably due to the presence of imprinted placental genes on the murine X chromosome, but not on the human homologue, essential for placental development and function. An example is the paternally imprinted Esx1 gene; mice with a null maternally derived Esx1 allele show intrauterine growth restriction (IUGR) because of placental insufficiency. We investigated the imprinting status of the human orthologous Esx1 gene (ESX1L) in placental samples of four normal full-term and 13 IUGR female fetuses, in which we determined the XCI pattern. Our findings demonstrated that IUGR as well as normal placentas display XCI heterogeneity, thus indicating that the IUGR phenotype is not correlated with a preferential pattern of XCI in placentas. Moreover, ESX1L is equally expressed in IUGR and normal placentas, and shows the same methylation pattern in the presence of both random and skewed XCI. These findings provide evidence that ESX1L is not imprinted in human third-trimester placentas and there is no parent-of-origin effect of chromosome X associated with placental insufficiency

Expression and clinical significance of extracellular matrix protein 1 and vascular endothelial growth factor-C in lymphatic metastasis of human breast cancer

<p>Abstract</p> <p>Background</p> <p>Extracellular matrix protein 1 (ECM1) and vascular endothelial growth factor-C (VEGF-C) are secretory glycoproteins that are associated with lymphangiogenesis; these proteins could, therefore, play important roles in the lymphatic dissemination of tumors. However, very little is known about their potential roles in lymphangiogenesis. The aim of this study was to investigate whether correlations exist between ECM1 and VEGF-C in human breast cancer, lymphangiogenesis, and the clinicopathological characteristics of the disease.</p> <p>Methods</p> <p><it>ECM1 </it>and <it>VEGF-C </it>mRNA and protein expression levels in 41 patients were investigated using real-time reverse transcriptase polymerase chain reaction (RT-PCR), or immunohistochemical (IHC) staining of breast cancer tissue, matched noncancerous breast epithelial tissues, and suspicious metastatic axillary lymph nodes. D2-40 labelled lymph vessels and lymphatic microvessel density (LMVD) were counted. Correlations between <it>ECM1 </it>or <it>VEGF-C </it>protein expression levels, LMVD, and clinicopathological parameters were statistically tested.</p> <p>Results</p> <p>The rate of ECM1 positive staining in breast cancer tissues was higher (31/41, 75.6%) than that in the corresponding epithelial tissues (4/41, 9.8%, <it>P </it>< 0.001) and lymph nodes (13/41, 31.7%, <it>P </it>< 0.001). Similarly, the VEGF-C expression rate in cancer specimens was higher (33/41, 80.5%) than in epithelial tissues (19/41, 46.3%, <it>P </it>< 0.01) or lymph nodes (15/41, 36.6%, <it>P </it>< 0.01). Higher <it>ECM1 </it>and <it>VEGF-C </it>mRNA expression levels were also detected in the tumor tissues, compared to the non-cancerous tissue types or lymph nodes (<it>P </it>< 0.05). ECM1 protein expression was positively correlated with the estrogen receptor status (<it>P </it>< 0.05) and LMVD (<it>P </it>< 0.05). LMVD in the ECM1- and VEGF-C-positive tumor specimens was higher than that in the tissue types with negative staining (<it>P </it>< 0.05).</p> <p>Conclusions</p> <p>Both <it>ECM1 </it>and <it>VEGF-C </it>were overexpressed in breast cancer tissue samples. ECM1 expression was positively correlated with estrogen responsiveness and the metastatic properties of breast cancer. We conclude, therefore, that ECM1 and VEGF-C may have a synergistic effect on lymphangiogenesis to facilitate lymphatic metastasis of breast cancer.</p