Downregulated lincRNA HOTAIR expression in ovarian cancer stem cells decreases its tumorgeniesis and metastasis by inhibiting epithelial-mesenchymal transition

Cancer Cell International, Feb 2015

Background Emerging evidence indicates that dysregulated long intervening non-coding RNA (lincRNA) HOTAIR correlates highly with tumor invasion and metastasis but a link between the high expression of HOTAIR and the metastatic cascade of cancer stem cells (CSCs) needs to be further studied. The purpose of this study was to investigate the effect of down-regulated HOTAIR expression on tumorgeniesis and metastasis of epithelial ovarian cancer (EOC) CSCs. CD117+CD44+CSCs were isolated from human EOC SKOV3 cell line by using a magnetic-activated cell sorting system, and were then transfected with the expression vector-based small hairpin RNA targeting HOTAIR; the stably transfected cells were selected for the study. Colony-forming, wound-healing, cellular metastasis and tumorigenicity assays were performed. Results The results demonstrated that the HOTAIR expression in clinical EOC tissues and SKOV3 CD117+CD44+CSCs was higher than in SKOV3 tumor tissues and non-CD117+CD44+CSCs. The CD117+CD44+-shHOTAIR showed an inhibited HOTAIR expression, reduced cell migration and invasion than CD117+CD44+- scramble, suggesting the inhibition of an epithelial-mesenchymal transition. Moreover, the downregulated HOTAIR expression in CD117+CD44+ CSCs significantly decreased the tumor growth and lung metastasis in xenograft mice. Conclusion Our findings demonstrated the shHOTAIR-mediated down-regulation of the HOTAIR expression in CD117+CD44+ CSCs can be a promising new opportunity for future clinical trials.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

http://www.cancerci.com/content/pdf/s12935-015-0174-4.pdf

Downregulated lincRNA HOTAIR expression in ovarian cancer stem cells decreases its tumorgeniesis and metastasis by inhibiting epithelial-mesenchymal transition

Wang et al. Cancer Cell International Downregulated lincRNA HOTAIR expression in ovarian cancer stem cells decreases its tumorgeniesis and metastasis by inhibiting epithelial-mesenchymal transition Jing Wang 1 Dengyu Chen 0 2 Xiangfeng He 4 Yuxia Zhang 0 1 Fangfang Shi 0 3 Di Wu 0 1 Junsong Chen 0 Ying Zhang 0 Fengsu Zhao 0 Jun Dou 0 0 Department of Pathogenic Biology and Immunology of School of Medicine, Southeast University , Nanjing 210009 , China 1 Department of Gynecology & Obstetrics, Zhongda Hospital, School of Medicine, Southeast University , Nanjing 210009 , China 2 Bengbu Medical School, Department of Microbiology , Bengbu 233030 , China 3 Department of Oncology, Zhongda Hospital, Southeast University , Nanjing 210009 , China 4 Department of Medical Oncology, Affiliated Tumor Hospital of Nantong University , Nantong 226361 , China Background: Emerging evidence indicates that dysregulated long intervening non-coding RNA (lincRNA) HOTAIR correlates highly with tumor invasion and metastasis but a link between the high expression of HOTAIR and the metastatic cascade of cancer stem cells (CSCs) needs to be further studied. The purpose of this study was to investigate the effect of down-regulated HOTAIR expression on tumorgeniesis and metastasis of epithelial ovarian cancer (EOC) CSCs. CD117+CD44+CSCs were isolated from human EOC SKOV3 cell line by using a magnetic-activated cell sorting system, and were then transfected with the expression vector-based small hairpin RNA targeting HOTAIR; the stably transfected cells were selected for the study. Colony-forming, wound-healing, cellular metastasis and tumorigenicity assays were performed. Results: The results demonstrated that the HOTAIR expression in clinical EOC tissues and SKOV3 CD117+CD44+CSCs was higher than in SKOV3 tumor tissues and non-CD117+CD44+CSCs. The CD117+CD44+-shHOTAIR showed an inhibited HOTAIR expression, reduced cell migration and invasion than CD117+CD44+- scramble, suggesting the inhibition of an epithelial-mesenchymal transition. Moreover, the downregulated HOTAIR expression in CD117 +CD44+ CSCs significantly decreased the tumor growth and lung metastasis in xenograft mice. Conclusion: Our findings demonstrated the shHOTAIR-mediated down-regulation of the HOTAIR expression in CD117+CD44+ CSCs can be a promising new opportunity for future clinical trials. Epithelial ovarian cancer; Cancer stem cells; LincRNA HOTAIR; Epithelial-mesenchymal transition; RNA interference - Introduction Human epithelial ovarian cancer (EOC) is one of malignant tumors in gynecological cancers and currently remains to be the number one the first leading cause of cancer-related deaths in women due to factors such as failure for its early dectection and diagnosis, its proneness to pelvic and peritoneal metastasis, and its resistance to chemotherapy after recurrence. Although many studies have been published in the past decade and have contributed to the advance of the knowledge in this field, the complex biology of EOC is still insufficiently understood [1,2]. Therefore, more recent studies have focused on the molecular mechanisms underlying the EOC progression and the new strategies for early clinical diagnosis and effective therapy [3,4]. Recent studies have demonstrated that cancer stem cells (CSCs) are responsible for tumour-initiating potential, metastasis and eventual relapse. Thus, the treatments that target CSCs may lead to the discovery of effective methods to eradicate the malignant tumor cells [5-7]. Emerging evidence supports that long intervening non-coding RNAs (lincRNAs) play a critical role in regulating cellular processes such as differentiation, proliferation, and metastasis [8,9]. HOX transcript antisense RNA (termed HOTAIR), one of lincRNAs, functions in epigenetic regulatory processes, interacts with polycomb repressive complex 2 and is required for histone H3 lysine-27 trimethylation of the HOD locus. In addtion, HOTAIR has been strongly associated with the invasion and metastasis of cancer cells [10]. Dysregulation of lncRNA HOTAIR has been considered a primary feature of several human cancers including breast cancer [10,11], hepatocellular carcinoma [12,13], colorectal cancer [14], pancreatic carcinomas [15], gastrointestinal stromal tumors [16], and human EOC [17,18]. Of the many functions of HOTAIR, as tumor regulatory factors, the one for silencing HOTAIR transcription in CSCs has remained insufficiently understood [17,19]. For this reason, we investigated whether the downregulated HOTAIR expression would decrease the human EOC SKOV3 CD117+CD44+CSC metastasis by inhibiting epithelial- mesenchymal transition (EMT) in vitro, as well as cellular tumorigenicity in nude mice. The data from our current study showed that epigenetic silencing of lncRNA HOTAIR in SKOV3 CD117+CD44+CSCs resulted in reduced cellular tumorgeniesis and metastasis in mouse model. This fingings suggested that the streatgy of downregulating the HOTAIR expres (...truncated)


This is a preview of a remote PDF: http://www.cancerci.com/content/pdf/s12935-015-0174-4.pdf

Jing Wang, Dengyu Chen, Xiangfeng He, Yuxia Zhang, Fangfang Shi, Di Wu, Junsong Chen, Ying Zhang, Fengsu Zhao, Jun Dou. Downregulated lincRNA HOTAIR expression in ovarian cancer stem cells decreases its tumorgeniesis and metastasis by inhibiting epithelial-mesenchymal transition, Cancer Cell International, 2015, pp. 24, 15, DOI: 10.1186/s12935-015-0174-4