{"paper_id":"347f7da1-e939-4006-bafd-a16f81bb792b","body_text":"Abstract\nAims\nK-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.\nMethods\nEmploying 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.\nResults\nWe 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.\nConclusion\nThe 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.\nSimilar content being viewed by others\nReferences\nRogers PA, D’Hooghe TM, Fazleabas A, Giudice LC, Montgomery GW, Petraglia F, Taylor RN (2013) Defining future directions for endometriosis research: workshop report from the 2011 World Congress of Endometriosis in Montpellier. France Reprod Sci 20(5):483–499\nHaas D, Chvatal R, Reichert B, Renner S, Shebl O, Binder H, Wurm P, Oppelt P (2012) Endometriosis: a premenopausal disease? Age pattern in 42,079 patients with endometriosis. Arch Gynecol Obstet 286(3):667–670\nBurney RO, Talbi S, Hamilton AE, Vo KC, Nyegaard M, Nezhat CR, Lessey BA, Giudice LC (2007) Gene expression analysis of endometrium reveals progesterone resistance and candidate susceptibility genes in women with endometriosis. Endocrinology 148(8):3814–3826\nDinulescu DM, Ince TA, Quade BJ, Shafer SA, Crowley D, Jacks T (2005) Role of K-ras and Pten in the development of mouse models of endometriosis and endometrioid ovarian cancer. Nat Med 11(1):63–70\nVercellini P, Trecca D, Oldani S, Fracchiolla NS, Neri A, Crosignani PG (1994) Analysis of p53 and ras gene mutations in endometriosis. Gynecol Obstet Invest 38(1):70–71\nOtsuka J, Okuda T, Sekizawa A, Amemiya S, Saito H, Okai T, Kushima M, Tachikawa T (2004) K-ras mutation may promote carcinogenesis of endometriosis leading to ovarian clear cell carcinoma. Med Electron Microsc 37(3):188–192\nKalnina Z, Zayakin P, Silina K, Line A (2005) Alterations of pre-mRNA splicing in cancer. Genes Chromosomes Cancer 42(4):342–357\nPlowman SJ, Berry RL, Bader SA, Luo F, Arends MJ, Harrison DJ, Hooper ML, Patek CE (2006) K-ras 4A and 4B are co-expressed widely in human tissues, and their ratio is altered in sporadic colorectal cancer. J Exp Clin Cancer Res 25(2):259–267\nHancock JF (2003) Ras proteins: different signals from different locations. Nat Rev Mol Cell Biol 4(5):373–384\nPlowman SJ, Williamson DJ, O’Sullivan MJ, Doig J, Ritchie AM, Harrison DJ, Melton DW, Arends MJ, Hooper ML, Patek CE (2003) While K-ras is essential for mouse development, expression of the K-ras 4A splice variant is dispensable. Mol Cell Biol 23(24):9245–9250\nVoice JK, Klemke RL, Le A, Jackson JH (1999) Four human ras homologs differ in their abilities to activate Raf-1, induce transformation, and stimulate cell motility. J Biol Chem 274(24):17164–17170\nGrechukhina O, Petracco R, Popkhadze S, Massasa E, Paranjape T, Chan E, Flores I, Weidhaas JB, Taylor HS (2012) A polymorphism in a let-7 microRNA binding site of KRAS in women with endometriosis. EMBO Mol Med 4(3):206–217\nLaudanski P, Szamatowicz J, Kowalczuk O, Kuzmicki M, Grabowicz M, Chyczewski L (2009) Expression of selected tumor suppressor and oncogenes in endometrium of women with endometriosis. Hum Reprod 24(8):1880–1890\nFarahani MS, Shahbazi S, Moghaddam SA, Mahdian R(2014) Evaluation of KRAS gene expression and LCS6 variant in genomic and cell-free DNA of Iranian women with endometriosis. Reprod Sci\nWang Y, You M (2001) Alternative splicing of the K-ras gene in mouse tissues and cell lines. Exp Lung Res 27(3):255–267\nKoera K, Nakamura K, Nakao K, Miyoshi J, Toyoshima K, Hatta T, Otani H, Aiba A, Katsuki M (1997) K-ras is essential for the development of the mouse embryo. Oncogene 15(10):1151–1159\nJohnson L, Greenbaum D, Cichowski K, Mercer K, Murphy E, Schmitt E, Bronson RT, Umanoff H, Edelmann W, Kucherlapati R et al (1997) K-ras is an essential gene in the mouse with partial functional overlap with N-ras. Genes Dev 11(19):2468–2481\nHurst BS, Shimp KE, Elliot M, Marshburn PB, Parsons J, Bahrani-Mostafavi Z (2014) Molecular evaluation of proliferative-phase endometrium may provide insight about the underlying causes of infertility in women with endometriosis. Arch Gynecol Obstet 289(5):1119–1124\nCritchley HO, Saunders PT (2009) Hormone receptor dynamics in a receptive human endometrium. Reprod Sci 16(2):191–199\nBromer JG, Aldad TS, Taylor HS (2009) Defining the proliferative phase endometrial defect. Fertil Steril 91(3):698–704\nPlowman SJ, Arends MJ, Brownstein DG, Luo F, Devenney PS, Rose L, Ritchie AM, Berry RL, Harrison DJ, Hooper ML et al (2006) The K-Ras 4A isoform promotes apoptosis but does not affect either lifespan or spontaneous tumor incidence in aging mice. Exp Cell Res 312(1):16–26\nVaskivuo TE, Stenback F, Karhumaa P, Risteli J, Dunkel L, Tapanainen JS (2000) Apoptosis and apoptosis-related proteins in human endometrium. Mol Cell Endocrinol 165(1–2):75–83\nKokawa K, Shikone T, Nakano R (1996) Apoptosis in the human uterine endometrium during the menstrual cycle. J Clin Endocrinol Metab 81(11):4144–4147\nDmowski WP, Ding J, Shen J, Rana N, Fernandez BB, Braun DP (2001) Apoptosis in endometrial glandular and stromal cells in women with and without endometriosis. Hum Reprod 16(9):1802–1808\nAcknowledgments\nThe authors acknowledge the contribution of the subjects in this study. This work was supported by Research Deputy of Tarbiat Modares University\nConflict of interest\nThe authors declare that they have no conflict of interest.\nAuthor information\nAuthors and Affiliations\nCorresponding author\nRights and permissions\nAbout this article\nCite this article\nShahrabi-Farahani, M., Shahbazi, S., Mahdian, R. et al. K-Ras 4A Transcript variant is up-regulated in eutopic endometrium of endometriosis patients during proliferative phase of menstrual cycle. Arch Gynecol Obstet 292, 225–229 (2015). https://doi.org/10.1007/s00404-014-3596-7\nReceived:\nAccepted:\nPublished:\nIssue date:\nDOI: https://doi.org/10.1007/s00404-014-3596-7","source_license":"CC0","license_restricted":false}