Large scale validation of human N-myc Downstream-Regulated Gene (NDRG)-1 expression in endometrium during the menstrual cycle

Abstract

A major challenge in the comprehension of the endometrial transformations leading to the completion of each menstrual cycle in humans is in the identification of specific molecular pathways underlying these monthly turnovers. Towards this goal we compared, by the differential display technique, the relative expression of mRNA in endometrial biopsies harvested in individuals (n = 48) either at the proliferative or the secretory phase of the menstrual cycle. We isolated a cDNA fragment homologous to NDRG1 (N-myc Downstream-Regulated Gene-1) that is present in markedly higher amounts in the secretory phase. Northern blot analysis and quantitative real time PCR experiments confirmed this result in distinct cohorts of individuals (44 and 560 respectively). A closer examination of data showed that the highest mRNA levels were found during the range of 25-28 days of the uterine cycle. Consistent with the mRNA data, the temporal profile of the NDRG1 protein showed a 15-fold increase during the secretory phase, as demonstrated by using semi-quantitative dot blot analyses (n = 92). Immunohistochemical localization revealed that NDRG1 was expressed both in epithelial and stromal cells. This large scale validation of the NDRG1 mRNA and protein increase in endometrium during the secretory phase is consistent with its differentiation-related function described in other tissues and its potential involvement in the window of implantation of the human endometrium, as suggested by previous chip-based evidence.

N-myc downstream regulated 1 gene and its place in the cellular machinery.

“…Examination of tissue samples derived from estrogenrelated endrometroid carcinoma showed that most of NDRG1-positive tissue exhibited a decrease in PTEN expression and most of PTEN-positive cancers displayed decreased expression of NDRG1 . The NDRG1 protein is undetectable in normal endometrium, but its level increases during the secretory phase of the menstrual cycle, which is consistent with its differentiation-related function (Malette et al, 2003). In endometroid carcinoma NDRG1 overexpression is observed but does not correlate with the differentiation degree Li et al, 2008).…”

NDRG4 is Downregulated in Glioblastoma and Inhibits Cell Proliferation

“…For example, NDRG1 is identified as a tumor suppressor-its expression could reduce the invasion and metastasis of breast, colon, prostate, and pancreatic cancers by modulating proliferation, differentiation, and angiogenesis of cancer cells (Kehlen et al, 2003;Kovacevic et al, 2008;Liu et al, 2011;Malette et al, 2003;Tschan et al, 2010). NDRG2 is also described as a tumor suppressor.…”

Expression analysis of the NDRG2 gene in mouse embryonic and adult tissues

“…Based on UniGene cluster analysis, the NDRG2 gene is located at chromosome 14q11.2 and is closely related to NDRG1 (Qu et al 2002). NDRG1 has been linked to stress responses (Park et al 2000;Agarwala et al 2000;Salnikow et al 2002;Ding et al 2003;Cangul 2004), cell proliferation (Piquemal et al 1999;Kim et al 2004;Sugiki et al 2004;Malette et al 2003), differentiation (Guan et al 2000;Gomez-Casero et al 2001;Li and Kretzner 2003;Burchfield et al 2004), and apoptosis (Stein et al 2004). NDRG2 is the physiological substrate for serum/glucocorticoid-induced kinase 1 (Murray et al 2004), a novel insulin-dependent phosphoprotein (Burchfield et al 2004) and a novel mineralocorticoid-specific mediator of early physiological response to aldosterone in target tight epithelia (Boulkroun et al 2002).…”