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
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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)