Original articleMicroarray expression profile analysis of long non-coding RNAs in human breast cancer: A study of Chinese women
Introduction
Breast cancer (BC) is the most common type of tumor in women. The incidence of breast cancer in western countries has decreased or at least been stable over the last few decades, but the incidence is increasing in China and in many developing countries [1]. The potential mechanisms that regulate breast cancer progression are still poorly understood. The development of BC is a complex multistep process associated with numerous genetic alterations [2]. Accordingly, the elucidation of the molecular mechanisms in BC has been the subject of extensive research over past decades. Clinically, delayed diagnosis, recurrence, and metastasis are still the biggest obstacles to the treatment of BC [3]. Therefore, searching for the ideal biomarkers and novel therapeutic targets of BC are essential for the diagnosis and treatment of BC.
Immune system functions as a host defensive mechanism protecting against invading pathogens and transformed cells, including cancer [4]. It has long been recognized that the immune system plays dual roles in the development of tumors [5]. Many experimental in vitro and in vivo studies have demonstrated that the immune network plays a significant role in the development and progression of BC [6], [7]. However, the underlying mechanisms are still poorly understood, especially the mechanisms explaining how the immune system dysfunction in breast cancer development.
Long non-coding RNA (lncRNA) are functional RNAs longer than 200 nucleotides in length. Over past few decade advances in genome-wide analyses have revealed that the human genome encodes over 10,000 lncRNAs with little coding capacity [8]. For a long time these lncRNAs have been considered as transcriptional noises, however, growing evidence suggests that lncRNAs are key regulators which governing various biological processes such as genomic imprinting, transcription activation and inhibition, chromatin modification and tissue development [9]. Dysregulation of lncRNAs is associated with many human diseases, including various types of cancers [10]. More recently, many lncRNAs have been shown to exert oncogenic or tumor suppressor properties in BC [11]. The well-studied lncRNA HOTAIR, for example, was found to be overexpressed in breast tumors, and the expression of HOTAIR in primary breast tumors was characterized as a negative prognostic factor in BC patients [12]. Although a few lncRNAs’ information accumulated in cancer, the functions of majority of lncRNAs remain largely unknown.
Hence, the aim of the present study was to perform lncRNA expression profiling to identify lncRNAs that might help to better diagnose and treat breast cancer. We identified a set of lncRNAs that were differentially expressed in breast cancer. Moreover, this study indicated that the dysregulated lncRNAs may disturb the immune network and promote the development of breast cancer. These findings will aid in our understanding of lncRNA function in immune system and may provide a basis for the diagnosis and therapy of breast cancer.
Section snippets
Tissues collection
Samples of breast cancer tissues consisting of tumors and adjacent sections from patients who had invasive breast cancer were collected consecutively between January 2013 and March 2014 at Nanjing Maternity and Child Health Care Hospital, Nanjing, China. This study was approved by the ethical review committee of Nanjing Maternity and Child Health Care Hospital affiliated to Nanjing Medical University. None of these patients accepts radiotherapy or chemotherapy prior to the breast tumor
Profile of microarray data
ArrayStar, Inc. (Rockville, MD, USA) Human lncRNA Microarray V 3.0 is designed for the global profiling of human lncRNAs and protein-coding transcripts. According microarray expression profiling data, 33664 lncRNAs and 23516 mRNAs were detected. In addition, 1486 lncRNAs (log fold-change > 2.3) were found differently expressed between BC samples and its paired adjacent tissue samples. All these lncRNAs were obtained from authoritative databases, RefSeq, UCSC Knowngenes, Ensembl and many related
Discussions
Breast cancer is the most common form of cancer in women and the second leading cause of death in females after lung cancer [20]. The development of breast cancer is a complex multistep process associated with numerous genetic genes, tumor suppressor genes, oncogenes and tumor cells hematogeneous dissemination [21]. Accordingly, the elucidation of the molecular mechanisms in breast cancer has been the subject of extensive research over the past decades. Several large-scale analyses have
Disclosure of interest
The authors declare that they have no conflicts of interest concerning this article.
Acknowledgments
We thank Miss Xun Lu (Jinling High School, Nanjing, China) for her help in collecting patient information. This work was supported by a Grant from the National Natural Science Foundation of China (No. 81172501)
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