A polymorphism in a let-7 microRNA binding site of KRAS in women with endometriosis

Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, USA.
EMBO Molecular Medicine (Impact Factor: 8.25). 03/2012; 4(3):206-17. DOI: 10.1002/emmm.201100200
Source: PubMed

ABSTRACT Endometriosis is found in 5-15% of women of reproductive age and is more frequent in relatives of women with the disease. Activation of KRAS results in de novo endometriosis in mice, however, activating KRAS mutations have not been identified in women. We screened 150 women with endometriosis for a polymorphism in a let-7 microRNA (miRNA) binding site in the 3'-UTR of KRAS and detected a KRAS variant allele in 31% of women with endometriosis as opposed to 5% of a large diverse control population. KRAS mRNA and protein expression were increased in cultured endometrial stromal cells of women with the KRAS variant. Increased KRAS protein was due to altered miRNA binding as demonstrated in reporter assays. Endometrial stromal cells from women with the KRAS variant showed increased proliferation and invasion. In a murine model, endometrial xenografts containing the KRAS variant demonstrated increased proliferation and decreased progesterone receptor levels. These findings suggest that an inherited polymorphism of a let-7 miRNA binding site in KRAS leads to abnormal endometrial growth and endometriosis. The LCS6 polymorphism is the first described genetic marker of endometriosis risk.


Available from: Idhaliz Flores, Apr 17, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: K-Ras transcripts comprise two main isoforms: K-Ras 4A and K-Ras 4B, which act differently. The expression of both isoforms was reported in many human tissues. However, K-Ras 4B was the major expressed transcript variant. An increased expression of K-Ras 4B mRNA was reported in eutopic endometrium of endometriosis patients. In this way, we aimed to study the expression of K-Ras 4A transcript in eutopic endometrium related to endometriosis. Employing exon4-flanking primers, K-Ras isoforms were simultaneously amplified in a RT-PCR reaction. Quantitative real-time PCR was performed using GAPDH as an internal control. K-Ras 4A transcript expression in eutopic endometrium was analyzed by ΔΔC T method. We identified existence of both of K-Ras 4A and K-Ras 4B in eutopic endometrium of patients and controls. Quantitative real-time analysis demonstrated that K-Ras 4A expression was 2.7-fold higher in endometriosis than non-endometriosis eutopic samples. Interestingly, this overexpression mainly occurs through the proliferative phase of menstrual cycle. The findings bring to light the eminent role of K-Ras 4A in endometriosis. This splice variant which is known for promoting apoptosis could be an effective factor in balance between proliferation and death of eutopic endometrial cells.
    Archives of Gynecology and Obstetrics 12/2014; DOI:10.1007/s00404-014-3596-7 · 1.28 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Polycystic ovary syndrome (PCOS) is the commonest endocrinopathy in women of reproductive age. The patients often develop insulin resistance (IR) or hyperinsulinemia despite manifesting anovulation and signs of hyperandrogenism. The cause and effect relationship of hyperinsulinemia and hyperandrogenemia (HA) is still debated. Micro-ribonucleic acids (miRNAs) have recently been shown to play a role in regulation of ovarian function. Our current study focused on the altered expression of miRNAs with PCOS. Ovarian theca interna tissues were obtained from 10 PCOS patients and 8 controls that were non-PCOS and had normal insulin sensitivity undergoing laparoscopy and/or ovarian wedge resection. Total RNA of all samples was extracted. We studied the repertoire of miRNAs in both PCOS and non-PCOS women by microarray hybridization. Bioinformatic analysis was performed for predicting targets of the differentially expressed miRNAs. Furthermore, selected miRNAs were validated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). A total of 27 miRNAs were differentially expressed in PCOS patients with respect to the controls in our discovery evaluationand two (miR-92a and miR-92b) of them were significantly downregulated in PCOS women in followed validation (P < 0.05). Targets prediction revealed that miR-92a targeted both GATA family of zinc finger transcription factor GATA-binding factor 6 (GATA6) and insulin receptor substrate proteins 2 (IRS-2). MiRNAs are differentially expressed between PCOS patients and controls. We identified and validated two miRNAs-miR-92a and miR-92b. They are significantly downregulated and may be involved in the pathogenesis of PCOS.
    Chinese medical journal 01/2015; 128(2):169-74. DOI:10.4103/0366-6999.149189 · 1.02 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sexual reproduction depends on a negotiation between the sexes at the level of the cells (gametes), tissue (trophectoderm of the blastocyst and endometrium in the uterus) and organisms (to allow sexual intercourse). This review evaluates new questions linked to sexual reproduction in the biosphere in the context of the 21st century, in light of current knowledge in genetics and epigenetics. It presents the challenge of 'forcing reproductive efficiency' using ineffective gametes, or despite other fertility problems, through medically assisted reproduction and presents the reproductive challenge of high production farm animals, which are in a situation of chronically negative energy balance. It also analyses the situation created by the release of endocrine disruptors into the environment and discusses the possible transgenerational consequences of environmental modifications linked to these compounds.
    Reproduction Fertility and Development 12/2014; 27(1):1-13. DOI:10.1071/RD14316 · 2.58 Impact Factor