Decreased carbonyl reductase 1 expression promotes malignant behaviours by induction of epithelial mesenchymal transition and its clinical significance Akihiro Murakami a,⇑ , Kazuyuki Yakabe a , Keiko Yoshidomi a , Kotaro Sueoka a , Shugo Nawata a , Yoshihito Yokoyama b , Shigeki Tsuchida c , Fahd Al-Mulla d , Norihiro Sugino a a Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube 755-8505, Japan b Department of Obstetrics and Gynecology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan c Second Department of Biochemistry, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan d Department of Pathology, University of Kuwait, PO Box 24923, Safat 13110, Kuwait article info Article history: Received 27 December 2011 Received in revised form 24 March 2012 Accepted 29 March 2012 Keywords: Carbonyl reductase 1 (CBR1) Endometrial cancer E-cadherin Epithelial mesenchymal transition (EMT) Mesenchymal epithelial transition (MET) abstract Human carbonyl reductase 1 (CBR1) is an enzyme that catalyse the reduction of many compounds by using NADPH-dependent oxydoreductase activity. Although CBR1 is known to regulate the tumour pro- gression, the molecular mechanisms of CBR1 in cancer progression and the clinical significance of CBR1 status remain unclear. Here, we investigated the molecular mechanisms by which CBR1 affects cancer cell behaviour in vitro and the clinical significance of CBR1 using immunohistochemical analyses in endo- metrial cancer. Here, the role of CBR1 in cancer cell invasion and metastasis, and its molecular mecha- nisms were investigated by transfection of sense and antisense CBR1 cDNAs into a human endometrial adenocarcinoma cell line. The relationship between CBR1 expression analysed by immunohistochemistry and prognosis such as progression free survival (PFS) and overall survival (OS) was examined in endome- trial cancer tissues from FIGO stage I–IV (n = 109). Suppression of CBR1 by antisense CBR1 cDNA increased cancer cell invasion, and suppressed E-cadherin expression and capacity for cellular aggregation. In contrast, over-expression of CBR1 by sense CBR1 cDNA increased E-cadherin expression and capacity for cellular aggregation, and suppressed cancer cell invasion. The expression of transcriptional suppres- sors of E-cadherin, Snail and ZEB1, were increased by CBR1 suppression, but suppressed by CBR1 over- expression. Immunohistochemical analyses showed that decreased CBR1 expression is significantly related with poor PFS and OS compared with strong CBR1 expression. In multivariate analyses, decreased CBR1 expression was an independent prognostic factor for PFS and OS. CBR1 regulates cancer cell inva- sion in endometrial adenocarcinomas by regulating the epithelial mesenchymal transition. A decreased CBR1 expression can be a useful marker of an unfavourable clinical outcome in patients with endometrial cancer. Ó 2012 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Human Carbonyl reductases (CBRs) are enzymes that catalyse the reduction of many carbonyl compounds by using NADPH- dependent oxydoreductase activity [1,2]. There are two mono- meric CBR genes in the human genome, cbr1 and cbr3, which exhibit high homology in their amino acid sequence [3]. CBR1 has been studied on its ability to reduce a variety of carbonyl com- pounds including antitumour anthracycline antibiotics, daunorubi- cin and doxorubicin, and prostaglandins [3,4]. Recently, CBR1 has been reported to play a role in regulating the malignant potential of cancer cells. Loss of CBR1 expression promotes tumour growth and metastatic behaviour [5,6], and decreased CBR1 expression is associated with lymph node metastasis and poor prognosis in ovarian cancer and uterine cervical cancer [6,7]. However, these reports did not show how decreased CBR1 is involved in malignant behaviour. Furthermore, the role of CBR1 in uterine endometrial cancer has not been examined. Several key factors have been reported to be involved in the malignant behaviour of cancer cells. For example, loss of E-cadherin or activation of matrix metalloproteinases (MMPs) is well known to promote cancer cell invasion and lymph node metastasis [8]. Recently, the epithelial mesenchymal transition (EMT) has been re- ported to play a role in tumour progression [9], although it was originally investigated as an embryological process [10,11]. In the EMT process, epithelial cells morphologically change to mesenchy- mal cells, which are similar in appearance to fibroblasts [9,10]. This change is associated with the losses of cell polarity and cell–cell tight adhesions [9–11]. In primary tumours, induction of EMT leads 0304-3835/$ - see front matter Ó 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.canlet.2012.03.035 ⇑ Corresponding author. Tel.: +81 836 22 2289; fax: +81 836 22 2287. E-mail address: muraaki@yamaguchi-u.ac.jp (A. Murakami). Cancer Letters 323 (2012) 69–76 Contents lists available at SciVerse ScienceDirect Cancer Letters journal homepage: www.elsevier.com/locate/canlet