Long Non-Coding RNAs as Mediators of Tumor Microenvironment and Liver Cancer Cell Communication

Abstract

The tumor microenvironment is an important concept that defines cancer development not only through tumor cells themselves but also the surrounding cellular and non-cellular components, including stromal cells, blood vessels, infiltrating inflammatory cells, cancer stem cells (CSC), cytokines, and growth factors, which act in concert to promote tumor cell survival and metastasis. Hepatocellular carcinoma (HCC) is one of the most common and aggressive human malignancies worldwide. Poor prognosis is largely attributable to the high rate of tumor metastasis, highlighting the importance of identifying patients at risk in advance and developing novel therapeutic targets to facilitate effective intervention. Long non-coding RNAs (lncRNA) are a class of non-protein coding transcripts longer than 200 nucleotides frequently dysregulated in various cancer types, which have multiple functions in widespread biological processes, including proliferation, apoptosis, metastasis, and metabolism. lncRNAs are involved in regulation of the tumor microenvironment and reciprocal signaling between cancer cells. Targeting of components of the tumor microenvironment or cancer cells has become a considerable focus of therapeutic research and establishing the effects of different lncRNAs on this network should aid in the development of effective treatment strategies. The current review provides a summary of the essential properties and functional roles of known lncRNAs associated with the tumor microenvironment in HCC.

Transcriptome analysis reveals the link between lncRNA-mRNA co-expression network and tumor immune microenvironment and overall survival in head and neck squamous cell carcinoma

“…Accumulating evidence suggests that lncRNAs play important roles in the regulation of immune-related processes [44,45]. In addition, it is widely recognized that lncRNAs are important regulatory factors in modulating the TIME and tumor progression [30,46]. Therefore, we constructed a functional lncRNA-mRNA co-expressed network using genes exhibiting expression differences between the high and low IS HNSCC male subgroups.…”

“…To date, evidence has shown that some lncRNAs (e.g., TSLNC8, MEG3) function as tumor suppressors [26,27], whereas others (e.g., HOTAIR, PVT1) serve as onco-lncRNAs [28,29]. Recent reports also state that lncRNAs can function by mediating the TME [30,31]; however, their potential regulatory roles in the TME and HNSCC progression remain unclear.…”

Roles of circRNAs in the tumour microenvironment

“…Extensive and in-depth research on the TME should importantly involve noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) [10][11][12] and long ncRNAs (lncRNAs) [13][14][15]. With the broad application of highthroughput RNA sequencing (RNA-seq), numerous circular RNAs (circRNAs) have been identified and characterized in humans and other eukaryotes.…”

Emerging Role of Non-Coding RNAs in Esophageal Squamous Cell Carcinoma

“…Conventional transcriptome studies focus on protein-coding genes. However, more than 90% of the mammalian genome has been reported to be composed of ncRNAs [9]. Typically, ncRNAs can be divided into housekeeper and regulatory ncRNAs.…”