Long Non-Coding RNA MALAT1 Interacts With miR-204 to Modulate Human Hilar Cholangiocarcinoma Proliferation, Migration, and Invasion by Targeting CXCR4

MALAT1: A Long Non-Coding RNA with Multiple Functions and Its Role in Processes Associated with Fat Deposition

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) belongs to the lncRNA molecules, which are involved in transcriptional and epigenetic regulation and the control of gene expression, including the mechanism of chromatin remodeling. MALAT1 was first discovered during carcinogenesis in lung adenocarcinoma, hence its name. In humans, 66 of its isoforms have been identified, and in pigs, only 2 are predicted, for which information is available in Ensembl databases (Ensembl Release 111). MALAT1 is expressed in numerous tissues, including adipose, adrenal gland, heart, kidney, liver, ovary, pancreas, sigmoid colon, small intestine, spleen, and testis. MALAT1, as an lncRNA, shows a wide range of functions. It is involved in the regulation of the cell cycle, where it has pro-proliferative effects and high cellular levels during the G1/S and mitotic (M) phases. Moreover, it is involved in invasion, metastasis, and angiogenesis, and it has a crucial function in alternative splicing during carcinogenesis. In addition, MALAT1 plays a significant role in the processes of fat deposition and adipogenesis. The human adipose tissue stem cells, during differentiation into adipocytes, secrete MALAT1 as one the most abundant lncRNAs in the exosomes. MALAT1 expression in fat tissue is positively correlated with adipogenic FABP4 and LPL. This lncRNA is involved in the regulation of PPARγ at the transcription stage, fatty acid metabolism, and insulin signaling. The wide range of MALAT1 functions makes it an interesting target in studies searching for drugs to prevent obesity development in humans. In turn, in farm animals, it can be a source of selection markers to control the fat tissue content.

Role of long non-coding RNAs in cholangiocarcinoma: A systematic review and meta-analysis

BACKGROUND

Cholangiocarcinoma (CCA), as a rare malignancy of the biliary tree, has a poor prognosis most of the time. CCA is highly epigenetically regulated and several long non-coding RNAs (lncRNA) have been investigated to have a diagnostic and prognostic role in CCA. The current study aimed to assess the studies finding relevant lncRNAs in CCA systematically.

METHODS

International databases, including PubMed, Cochrane Library, and Embase, were comprehensively searched in order to identify studies investigating any lncRNA in CCA. After screening by title/abstract and full-text, necessary data were extracted. Random-effect meta-analysis was performed for pooling the areas under the curve (AUCs), specificity, and sensitivity of lncRNAs for the diagnosis of CCA.

RESULTS

A total of 33 studies were chosen to be included in the final analysis, comprised of 2677 patients. Meta-analysis of AUCs for evaluation of CCA resulted in pooled AUC of 0.79 (95% CI: 0.75-0.82; I2 = 69.11, p < .01). Additionally, overall sensitivity of 0.80 (95% CI 0.75-0.84) and specificity of 0.77 (95% CI: 0.68-0.84) were observed. Measurement of lncRANs in the assessment of CCA also improved overall survival significantly (effect size 1.61, 95% CI: 1.39-1.82). A similar result was found for progression-free survival (effect size 1.57, 95% CI: 1.20-1.93).

CONCLUSION

Based on our findings, lncRNAs showed promising results as biomarkers in the diagnosis of CCA since they had acceptable sensitivity and specificity, in addition to the fact that improved survival in this poor prognosis cancer. Further studies might be needed to address this issue and find the best clinically useful lncRNA.

LINC00844 suppresses tumor progression and predicts survival outcomes through inhibiting miR-19a-5p in cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is a heterogeneous malignancy. The aim of the study was to investigate the regulatory role of long noncoding RNA LINC00844 in CCA progression, explore the underlying molecular mechanisms, and to analyze the potential prognostic value of LINC00844 in CCA patients.

METHODS

Expression of LINC00844 in CCA cell lines and tissues was examined by reverse transcription-quantitative PCR. Cell counting kit-8 assay was used to assess CCA cell proliferation, and the Transwell assay was used to evaluate tumor cell migration and invasion. miRNAs sponged by LINC00844 were predicted and confirmed using a luciferase reporter assay. Kaplan-Meier survival analysis was performed to evaluate the survival prognosis of CCA patients.

RESULTS

The expression levels of LINC00844 were decreased in CCA tissues and cells. Overexpression of LINC00844 inhibited cell proliferation, migration and invasion in CCA cells. miR-19a-5p is directly targeted by LINC00844, mediating the inhibitory effects of LINC00844 on the proliferation, migration and invasion of CCA cells. LINC00844 and miR-19a-5p expression were associated with differentiation and tumor node metastasis stage in CCA patients. CCA patients with low LINC00844 expression or overexpression of miR-19a-5p had worse overall survival.

CONCLUSION

The expression levels of LINC00844 were decreased in both CCA tissues and cells, and high LINC00844 inhibited CCA cell proliferation, migration and invasion through sponging miR-19a-5p. Low LINC00844 and high miR-19a-5p expression were associated with worse overall survival in CCA patients. All the data suggested that the LINC00844/miR-19a-5p axis may provide novel therapeutic targets and prognostic biomarkers for CCA patients.

A review on the role of ncRNAs in the pathogenesis of cholangiocarcinoma

Cholangiocarcinoma is a rare tumor but a challenging cancer in terms of pathological changes, clinical manifestations and therapeutic options. Recent studies have provided evidence for participation of non-coding RNAs in the carcinogenic process of cholangiocarcinoma. We demonstrate the role of long non-coding RNAs, microRNAs and circular RNAs in the pathogenesis of cholangiocarcinoma and highlight their significant position as therapeutic targets and biomarkers for this type of cancer. We also list a number of molecular axes comprising these non-coding RNAs that represent potential targets for therapeutic options in cholangiocarcinoma, based on their significant roles in the regulation of cell proliferation, differentiation and apoptosis of these cells.

An overview of extrahepatic cholangiocarcinoma: from here to where?

Extrahepatic cholangiocarcinoma (eCCA) contains perihilar cholangiocarcinoma and distal cholangiocarcinoma both of which can arise at any point of the biliary tree and originate from disparate anatomical sites. Generally, the incidence of eCCA is increasing globally. Though surgical resection is the principal treatment of choice for the early stages of eCCA, optimal survival remains restricted by the high risk of recurrence when most patients are present with unresectable disease or distant metastasis. Furthermore, both intra- and intertumoral heterogeneity make it laborious to determine molecularly targeted therapies. In this review, we mainly focused on current findings in the field of eCCA, mostly including epidemiology, genomic abnormalities, molecular pathogenesis, tumor microenvironment, and other details while a summary of the biological mechanisms driving eCCA may shed light on intricate tumorigenesis and feasible treatment strategies.

Demystifying the CXCR4 conundrum in cancer biology: Beyond the surface signaling paradigm

The oncogenic chemokine duo CXCR4-CXCL12/SDF-1 (C-X-C Receptor 4-C-X-C Ligand 12/ Stromal-derived factor 1) has been the topic of intense scientific disquisitions since Muller et al., in her ground-breaking research, described this axis as a critical determinant of organ-specific metastasis in breast cancer. Elevated CXCR4 levels correlate with distant metastases, poor prognosis, and unfavourable outcomes in most solid tumors. Therapeutic impediment of the axis in clinics with Food and Drug Administration (FDA) approved inhibitors like AMD3100 or Plerixafor yield dubious results, contrary to pre-clinical developments. Clinical trials entailing inhibition of CXCR7 (C-X-C Receptor 7), another convicted chemokine receptor that exhibits affinity for CXCL12, reveal outcomes analogous to that of CXCR4-CXCL12 axis blockade. Of note, the cellular CXCR4 knockout phenotype varies largely from that of inhibitor treatments. These shaky findings pique great curiosity to delve further into the realm of this infamous chemokine receptor to provide a probable explanation. A multitude of recent reports suggests the presence of an increased intracellular CXCR4 pool in various cancers, both cytoplasmic and nuclear. This intracellular CXCR4 protein reserve seems active as it correlates with vital tumor attributes, viz. prognosis, aggressiveness, metastasis, and disease-free survival. Diminishing this entire intracellular CXCR4 load apart from the surface signals looks encouraging from a therapeutic point of view. Transcending beyond the classically accepted concept of ligand-mediated surface signaling, this review sheds new light on plausible associations of intracellularly compartmentalised CXCR4 with various aspects of tumorigenesis. Besides, this review also puts forward a comprehensive account of CXCR4 regulation in different cancers.

MicroRNA-204-5p: A pivotal tumor suppressor

MicroRNAs (miRNAs) are a class of non-coding single-stranded RNA molecules with a length of approximately 18-25 nt nucleotides that regulate gene expression post-transcriptionally. MiR-204-5p originates from the sixth intron of the transient receptor potential cation channel subfamily M member 3 (TRPM3) gene. MiR-204-5p is frequently downregulated in various cancer types and is related to the clinicopathological characteristics and prognosis of cancer patients. So far, many studies have determined that miR-204-5p functions as a tumor suppressor for its extensive and powerful capacity to inhibit tumor proliferation, metastasis, autophagy, and chemoresistance in multiple cancer types. MiR-204-5p appears to be a promising prognostic biomarker and a therapeutic target for human cancers. This review summarized the latest advances on the role of miR-204-5p in human cancers.

Long Non-Coding RNAs as Molecular Biomarkers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a biliary system cancer that has the characteristics of strong invasiveness, poor prognosis, and few therapy choices. Furthermore, the absence of precise biomarkers for early identification and prognosis makes it hard to intervene in the early phase of initial diagnosis or recurring cholangiocarcinoma following surgery. Encouragingly, previous studies found that long non-coding RNA (lncRNA), a subgroup of RNA that is more than 200 nucleotides long, can affect cell proliferation, migration, apoptosis, and even drug resistance by altering numerous signaling pathways, thus reaching pro-cancer or anti-cancer outcomes. This review will take a retrospective view of the recent investigations on the work of lncRNAs in cholangiocarcinoma progression and the potential of lncRNAs serving as promising clinical biomarkers and therapeutic targets for CCA.

Epigenetic Regulation of CXCR4 Signaling in Cancer Pathogenesis and Progression

Signaling involving chemokine receptor CXCR4 and its ligand SDF-1/CXL12 has been investigated for many years for its possible role in cancer progression and pathogenesis. Evidence emerging from clinical studies in recent years has further established diagnostic as well as prognostic importance of CXCR4 signaling. CXCR4 and SDF-1 are routinely reported to be elevated in tumors, distant metastases, which correlates with poor survival of patients. These findings have kindled interest in the mechanisms that regulate CXCR4/SDF-1 expression. Of note, there is a particular interest in the epigenetic regulation of CXCR4 signaling that may be responsible for upregulated CXCR4 in primary as well as metastatic cancers. This review first lists the clinical evidence supporting CXCR4 signaling as putative cancer diagnostic and/or prognostic biomarker, followed by a discussion on reported epigenetic mechanisms that affect CXCR4 expression. These mechanisms include regulation by non-coding RNAs, such as, microRNAs, long non-coding RNAs and circular RNAs. Additionally, we also discuss the regulation of CXCR4 expression through methylation and acetylation. Better understanding and appreciation of epigenetic regulation of CXCR4 signaling can invariably lead to identification of novel therapeutic targets as well as therapies to regulate this oncogenic signaling.

The axis of long non-coding RNA MALAT1/miR-1-3p/CXCR4 is dysregulated in patients with diabetic neuropathy

Background

Diabetic neuropathy (DN) is a prevalent complication of diabetes mellitus characterized by pain and inflammation. Long non-coding RNAs (lncRNAs) have been associated with DN. This study aimed to investigate transcript levels of Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), microRNA (miR)-1-3p, and C-X-C motif chemokine receptor 4 (CXCR4) in the DN patients and type 2 diabetes mellitus (T2DM) cases without neuropathy.

Methods

Here, 20 cases with DN and 20 T2DM subjects without neuropathy (as the control group) were included. Total RNA was extracted from peripheral blood mononuclear cells (PBMCs) of all participants. The expression levels of targets were evaluated by Real-time-PCR.

Results

Results showed that MALAT1 (Fold change = 2.47, P = 0.03) and CXCR4 (Fold change = 1.65, P = 0.023) were significantly upregulated, while miR-1-3p was downregulated (Fold change = 0.9, P = 0.028) in whole blood samples from DN patients compared to the control group. A significant correlation was found between transcript levels of MALAT1 and CXCR4 (rho = 0.84; P < 0.0001).

Conclusions

This study suggests a possible involvement of the MALAT1/miR-1-3p/CXCR4 axis in the pathogenesis of DN.

LINC00853 restrains T cell acute lymphoblastic leukemia invasion and infiltration by regulating CCR9/CCL25

BACKGROUND

Leukemia is a group of hematopoietic malignancies characterized by the accumulation and infiltration of abnormal hematopoietic stem cells or early progenitor cells. T cell acute lymphoblastic leukemia (T-ALL) is a hematologic malignancy occurring in 15 % of pediatric and 25 % of adult ALL cases. Infiltration and metastasis of leukemic cells to specific organs are consequences of disease relapse and dismal prognosis. Long non-coding RNAs (lncRNAs) have been identified to function in the migration, invasion and infiltration of tumors by regulating gene expression. Our previous studies showed that CC chemokine receptor 9 (CCR9), which specifically bind to CC chemokine ligand 25 (CCL25), promotes T-ALL infiltration.

METHODS

Bioinformatic methods were used to screen LINC00853 in gene expression omnibus (GEO) datasets. RT-qPCR, western bolt and flow cytometry were applied to detect the expression of LINC00853 and CCR9. Transwell and martrigel-transwell were employed to assess the cells migration and invasion abilities. Fluorescence microscope was applied to observed the green fluorescence protein positive (GFP⁺) cells. Lentivirus and adenovirus were packed to construct nc-blank, sh-LINC00853-blank and sh-LINC00853-rescue jurkat cell lines.

RESULTS

In this study, we found out the negative correlation of LINC00853 and CCR9 expression. LINC00853 was downregulated while CCR9 was upregulated in GEO datasets, T-ALL cell lines and clinical samples. Moreover, LINC00853 suppressed jurkat cells migration and invasion in vitro and restrained infiltration in liver, spleen, kidney, lung, brain, ovary of nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice.

CONCLUSIONS

These findings indicate that LINC00853 restrains T-ALL cell invasion and infiltration by regulating CCR9/CCL25.

Biliary Tract Cancers: Treatment Updates and Future Directions in the Era of Precision Medicine and Immuno-Oncology

The effective management of biliary tract cancers (BTCs) has been hampered by limited options for systemic therapy. In recent years, the focus on precision medicine has made technologies such as next-generation sequencing (NGS) accessible to clinicians to identify targetable mutations in BTCs in tumor tissue (primarily) as well as blood, and to treat them with targeted therapies when possible. It has also expanded our understanding of functional pathways associated with genetic alterations and opened doors for identifying novel targets for treatment. Recent advances in the precision medicine approach allowed us to identify new molecular markers in BTCs, such as epigenetic changes (methylation and histone modification) and non-DNA markers such as messenger RNA, microRNA, and long non-coding RNA. It also made detecting these markers from non-traditional sources such as blood, urine, bile, and cytology (from fine-needle aspiration and biliary brushings) possible. As these tests become more accessible, we can see the integration of different molecular markers from all available sources to aid physicians in diagnosing, assessing prognosis, predicting tumor response, and screening BTCs. Currently, there are a handful of approved targeted therapies and only one class of immunotherapy agents (immune checkpoint inhibitors or ICIs) to treat BTCs. Early success with new targets, vascular endothelial growth factor receptor (VEGFR), HER2, protein kinase receptor, and Dickkopf-1 (DKK1); new drugs for known targets, fibroblast growth factor receptors (FGFRs) such as futabatinib, derazantinib, and erdafitinib; and ICIs such as durvalumab and tremelimumab is encouraging. Novel immunotherapy agents such as bispecific antibodies (bintrafusp alfa), arginase inhibitors, vaccines, and cellular therapy (chimeric antigen receptor-T cell or CAR-T, natural killer cells, tumor-infiltrating lymphocytes) have the potential to improve outcomes of BTCs in the coming years.

LncRNA PTTG3P induced aberrant glycosylated IgA1 production and B cell growth in IgA nephropathy

Growing evidences suggested that lncRNAs played functional role in several cell functions such as cell growth, invasion, migration, metabolize, apoptosis, and differentiation. However, roles of lncRNA in the development and progression of IgAN remain unknown. In this reference, we indicated that PTTG3P level was overexpressed in IgAN samples compared to healthy subject. PTTG3P expression was also higher in urinary of IgAN cases than in urinary of healthy control. Furthermore, the urinary expression of PTTG3P was correlated with PTTG3P expression in intra-renal of IgAN cases. PTTG3P overexpression induced B cell growth and enhanced cyclin D1 and ki-67 expression. Overexpression of PTTG3P induced IL-1β and IL-8 production. miR-383 level was decreased in IgAN samples compared to healthy subject. In addition, miR-383 expression was also lower in urinary of IgAN cases than in urinary of healthy control. Elevated miR-383 expression decreased luciferase intensity regulated with PTTG3P, while overexpression of miR-383 had no effect on luciferase intensity of the mutant PTTG3P. PTTG3P overexpression suppressed miR-383 expression in B cells. Ectopic miR-383 expression suppressed B cell growth and IL-1β and IL-8 production. Finally, we showed that overexpression of PTTG3P promoted B cell growth and IL-1β and IL-8 production via regulating miR-383. There results proved that PTTG3P played crucial role in progression of IgAN.

Cholangiocarcinoma and liver transplantation: What we know so far?

Cholangiocarcinoma (CCA) is a type of cancer with increasing prevalence around the world that originates from cholangiocytes, the epithelial cells of the bile duct. The tumor begins insidiously and is distinguished by high grade neoplasm, poor outcome, and high risk for recurrence. Liver transplantation has become broadly accepted as a treatment option for CCA. Liver transplantation is expected to play a crucial role as palliative and curative therapy for unresectable hilar CCA and intrahepatic CCA. The purpose of this study was to determine which cases with CCA should be subjected to liver transplantation instead of resection, although reported post-transplant recurrence rate averages approximately 20%. This review also aims to highlight the molecular current frontiers of CCA and directions of liver transplantation for CCA.

Knockdown of lncRNA MALAT1 ameliorates acute kidney injury by mediating the miR-204/APOL1 pathway

Background

Acute kidney injury (AKI) was characterized by loss of renal function, associated with chronic kidney disease, end‐stage renal disease, and length of hospital stay. Long non‐coding RNAs (lncRNAs) participated in AKI development and progression. Here, we aimed to investigate the roles and mechanisms of lncRNA MALAT1 in AKI.

Methods

AKI serum samples were obtained from 129 AKI patients. ROC analysis was conducted to confirm the diagnostic value of MALAT1 in differentiating AKI from healthy volunteers. After hypoxic treatment on HK‐2 cells, the expressions of inflammatory cytokines, MALAT1, miR‐204, APOL1, p65, and p‐p65, were measured by RT‐qPCR and Western blot assays. The targeted relationship between miR‐204 and MALAT1 or miR‐204 and APOL1 was determined by luciferase reporter assay and RNA pull‐down analysis. After transfection, CCK‐8, flow cytometry, and TUNEL staining assays were performed to evaluate the effects of MALAT1 and miR‐204 on AKI progression.

Results

From the results, lncRNA MALAT1 was strongly elevated in serum samples from AKI patients, with the high sensitivity and specificity concerning differentiating AKI patients from healthy controls. In vitro, we established the AKI cell model after hypoxic treatment. After experiencing hypoxia, we found significantly increased MALAT1, IL‐1β, IL‐6, and TNF‐α expressions along with decreased miR‐204 level. Moreover, the targeted relationship between MALAT1 and miR‐204 was confirmed. Silencing of MALAT1 could reverse hypoxia‐triggered promotion of HK‐2 cell apoptosis. Meanwhile, the increase of IL‐1β, IL‐6, and TNF‐α after hypoxia treatment could be repressed by MALAT1 knockdown as well. After co‐transfection with MALAT1 silencing and miR‐204 inhibition, we found that miR‐204 could counteract the effects of MALAT1 on HK‐2 cell progression and inflammation after under hypoxic conditions. Finally, NF‐κB signaling was inactivated while APOL1 expression was increased in HK‐2 cells after hypoxia treatment, and lncRNA MALAT1 inhibition reactivated NF‐κB signaling while suppressed APOL1 expression by sponging miR‐204.

Conclusions

Collectively, these results illustrated that knockdown of lncRNA MALAT1 could ameliorate AKI progression and inflammation by targeting miR‐204 through APOL1/NF‐κB signaling.

MicroRNAs: emerging driver of cancer perineural invasion

The perineural invasion (PNI), which refers to tumor cells encroaching on nerve, is a clinical feature frequently occurred in various malignant tumors, and responsible for postoperative recurrence, metastasis and decreased survival. The pathogenesis of PNI switches from 'low-resistance channel' hypothesis to 'mutual attraction' theory between peripheral nerves and tumor cells in perineural niche. Among various molecules in perineural niche, microRNA (miRNA) as an emerging modulator of PNI through generating RNA-induced silencing complex (RISC) to orchestrate oncogene and anti-oncogene has aroused a wide attention. This article systematically reviewed the role of microRNA in PNI, promising to identify new biomarkers and offer cancer therapeutic targets.

MALAT1: A Promising Therapeutic Target for the Treatment of Metastatic Colorectal Cancer

Cancer metastasis research has emerged in recent years as one of the most important topics of debate in the discovery and development of novel anticancer therapies. Colorectal cancer (CRC), the third most common cancer worldwide, has a high mortality rate due to recurrence and distant metastasis to the liver. Several non-coding RNAs (ncRNAs) have been linked to metastatic CRC (mCRC), including the long non-coding RNA (lncRNA) Metastasis-Associated Lung-Adenocarcinoma Transcript 1 (MALAT1). MALAT1 is an RNA that has been linked to tumor cell proliferation, progression, epithelial-mesenchymal transition (EMT), cell migration and invasion, metastasis, and survival in mammalian species. Previously, there was no convincing evidence linking MALAT1 to mCRC. Studies have shown that MALAT1 functions as a competitive endogenous RNA (ceRNA) with microRNAs (miRNAs) and interacts directly with oncogenes and proteins. This RNA also activates several signaling pathways, including Wnt/β-catenin, PI3K/Akt/mTOR, and EMT. Meanwhile, standard chemotherapy and immunotherapy are the current treatment options for mCRC patients. However, evidence-based studies have recently demonstrated that inhibiting the MALAT1 RNA transcript can be considered as a treatment option for mCRC, highlighting the need to investigate its roles as a therapeutic target in mCRC. Thus, in this review, we looked at studies that linked MALAT1 to multiple signaling pathways implicated in mCRC, as well as its potential as a therapeutic target for the treatment of mCRC.

Long non-coding RNA MALAT1 modulate cell migration, proliferation and apoptosis by sponging microRNA-146a to regulate CXCR4 expression in acute myeloid leukemia

OBJECTIVES

To investigate the role of Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in acute myeloid leukemia (AML) and analyze the potential regulatory network of MALAT1/miR-146a/ CXCR4.

METHODS

The expressions of MALAT1, miR-146a and CXCR4 were performed by qRT-PCR and Western Blot. We conducted trans-well assay, CCK-8 assay and flow cytometry to evaluate the migration, proliferation and apoptosis of AML cells. Also by using luciferase reporter assay, we investigated the interaction between miR-146a and MALAT1 or CXCR4.

RESULTS

Firstly, MALAT1 and CXCR4 were upregulated while miR-146a was downregulated in AML patients compared with healthy controls. We observed a negative correlation between miR-146a and MALAT1 or CXCR4, but a positive correlation between MALAT1 and CXCR4 in AML patients. MALAT1 knockdown inhibited migration and proliferation but induced apoptosis of HL-60 cells. MALAT1 restrained miR-146a expression by acting as a ceRNA. miR-146a regulated HL-60 cells migration, proliferation and apoptosis by directly targeting CXCR4 expression. Finally, we found that CXCR4 expression was downregulated by MALAT1 knockdown and partially restored by miR-146a abrogation.

CONCLUSIONS

Our results showed that MALAT1 regulates migration, proliferation and apoptosis by sponging miR-146a to regulate CXCR4 expression in AML cells, providing novel insights into the role of MALAT1 as a therapeutic target in AML.

LncRNA ROR1-AS1 accelerates osteosarcoma invasion and proliferation through modulating miR-504

Long non-coding RNAs (LncRNAs) play vital roles in the progression and development of tumors. However, the functional role of ROR1-AS1 in osteosarcoma has not been investigated. We found that ROR1-AS1 was upregulated in osteosarcoma tissues compared to non-tumor samples. Elevated expression of ROR1-AS1 promoted cyclin D1, PCNA and ki-67 expression and increased cell cycle and growth in MG-63 cell. Moreover, overexpression of ROR1-AS1 induced cell migration in MG-63 cell, promoting N-cadherin and vimentin expression and inhibiting E-cadherin expression. Dual-luciferase assay proved that ROR1-AS1 served as one sponge for miR-504 and ROR1-AS1 overexpression suppressed miR-504 expression in MG-63 cell. ROR1-AS1 expression was lower in osteosarcoma tissues compared to non-tumor samples. Pearson's correlation assay showed a negative correlation between miR-504 and ROR1-AS1 expression. MiR-504 overexpression partly abrogated ROR1-AS1-induced effects on osteosarcoma cell migration and proliferation. These data implied that ROR1-AS1 played as an oncogene and might be a new treatment target for osteosarcoma.

Emerging roles of long noncoding RNAs in cholangiocarcinoma: Advances and challenges

Cholangiocarcinoma (CCA), a cancer with a relatively low incidence rate, is usually associated with poor prognosis. Current modalities for the diagnosis and treatment of CCA patients are still far from satisfactory. In recent years, numerous long noncoding RNAs (lncRNAs) have been identified as crucial players in the development of various cancers, including CCA. Abnormally expressed lncRNAs in CCA, regulated by some upstream molecules, significantly influence the biological behavior of tumor cells and are involved in tumor development through various mechanisms, including interactions with functional proteins, participation in competing for endogenous RNA (ceRNA) regulatory networks, activation of cancer‐related signaling pathways and epigenetic modification of gene expression. Furthermore, several lncRNAs are closely associated with the clinicopathological features of CCA patients, and are promising biomarkers for diagnosing and prognostication of CCA. Some of these lncRNAs play an important role in chemotherapy drug resistance. In addition, lncRNAs have also been shown to be involved in the inflammation microenvironment of CCA and malignant outcome of CCA risk factors, such as cholestatic liver diseases. In view of the difficulty of diagnosing CCA, more attention should be paid to detectable lncRNAs in the serum or bile. This review summarizes the recent knowledge on lncRNAs in CCA and provides a new outlook on the molecular mechanisms of CCA development from the perspective of lncRNAs. Moreover, we also discussed the limitations of the current studies and differential expression of lncRNAs in different types of CCA.

Regulatory Networks of LncRNA MALAT-1 in Cancer

Long noncoding (lnc)RNAs are a group of RNAs with a length greater than 200 nt that do not encode a protein but play an essential role in regulating the expression of target genes in normal biological contexts as well as pathologic processes including tumorigenesis. The lncRNA metastasis-associated lung adenocarcinoma transcript (MALAT)-1 has been widely studied in cancer. In this review, we describe the known functions of MALAT-1; its mechanisms of action; and associated signaling pathways and their clinical significance in different cancers. In most malignancies, including lung, colorectal, thyroid, and other cancers, MALAT-1 functions as an oncogene and is upregulated in tumors and tumor cell lines. MALAT-1 has a distinct mechanism of action in each cancer type and is thus at the center of large gene regulatory networks. Dysregulation of MALAT-1 affects cellular processes such as alternative splicing, epithelial–mesenchymal transition, apoptosis, and autophagy, which ultimately results in the abnormal cell proliferation, invasion, and migration that characterize cancers. In other malignancies, such as glioma and endometrial carcinoma, MALAT-1 functions as a tumor suppressor and thus forms additional regulatory networks. The current evidence indicates that MALAT-1 and its associated signaling pathways can serve as diagnostic or prognostic biomarker or therapeutic target in the treatment of many cancers.

Exosomal noncoding RNAs in cholangiocarcinoma: Laboratory noise or hope?

Currently, extracellular vesicles and particularly exosomes have gained a lot of research interest due to their unique roles in several biological processes. Noncoding RNAs (microRNAs, long noncoding RNAs and circular RNAs) represent a class of functional RNA with distinct regulatory roles in tumorigenesis and cancer progression. Cholangiocarcinoma is a rare but highly aggressive type of malignancy that is very challenging to diagnose, especially in early stages; surgical resection still represents the sole potentially curative treatment option. Hence, there is an urgent need for the discovery of novel diagnostic and prognostic biomarkers. Hereby, we provide a comprehensive review of the most recent discoveries that focus on exosomal noncoding RNAs in cholangio-carcinoma with the aim to identify new molecular players that could be used as biomarkers and therapeutic targets.

Reconstruction of lncRNA-miRNA-mRNA network based on competitive endogenous RNA reveals functional lncRNAs in skin cutaneous melanoma

BACKGROUND

Human skin cutaneous melanoma is the most common and dangerous skin tumour, but its pathogenesis is still unclear. Although some progress has been made in genetic research, no molecular indicators related to the treatment and prognosis of melanoma have been found. In various diseases, dysregulation of lncRNA is common, but its role has not been fully elucidated. In recent years, the birth of the "competitive endogenous RNA" theory has promoted our understanding of lncRNAs.

METHODS

To identify the key lncRNAs in melanoma, we reconstructed a global triple network based on the "competitive endogenous RNA" theory. Gene Ontology and KEGG pathway analysis were performed using DAVID (Database for Annotation, Visualization, and Integration Discovery). Our findings were validated through qRT-PCR assays. Moreover, to determine whether the identified hub gene signature is capable of predicting the survival of cutaneous melanoma patients, a multivariate Cox regression model was performed.

RESULTS

According to the "competitive endogenous RNA" theory, 898 differentially expressed mRNAs, 53 differentially expressed lncRNAs and 16 differentially expressed miRNAs were selected to reconstruct the competitive endogenous RNA network. MALAT1, LINC00943, and LINC00261 were selected as hub genes and are responsible for the tumorigenesis and prognosis of cutaneous melanoma.

CONCLUSIONS

MALAT1, LINC00943, and LINC00261 may be closely related to tumorigenesis in cutaneous melanoma. In addition, MALAT1 and LINC00943 may be independent risk factors for the prognosis of patients with this condition and might become predictive molecules for the long-term treatment of melanoma and potential therapeutic targets.

Panel of potential lncRNA biomarkers can distinguish various types of liver malignant and benign tumors

PURPOSE

Liver cancers are among the deadliest malignancies due to a limited efficacy of early diagnostics, the lack of appropriate biomarkers and insufficient discrimination of different types of tumors by classic and molecular methods. In this study, we searched for novel long non-coding RNA (lncRNA) as well as validated several known candidates suitable as probable biomarkers for primary liver tumors of various etiology.

METHODS

We described a novel lncRNA HELIS (aka "HEalthy LIver Specific") and estimated its expression by RT-qPCR in 82 paired tissue samples from patients with hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), combined HCC-CCA, pediatric hepatoblastoma (HBL) and non-malignant hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH). Additionally, we examined expression of cancer-associated lncRNAs HULC, MALAT1, UCA1, CYTOR, LINC01093 and H19, which were previously studied mainly in HCC.

RESULTS

We demonstrated that down-regulation of HELIS strongly correlates with carcinogenesis; whereas in tumors with non-hepatocyte origin (HBL, CCA) or in a number of poorly differentiated HCC, this lncRNA is not expressed. We showed that recently discovered LINC01093 is dramatically down-regulated in all malignant liver cancers; while in benign tumors LINC01093 expression is just twice decreased in comparison to adjacent samples.

CONCLUSION

Our study revealed that among all measured biomarkers only down-regulated HELIS and LINC01093, up-regulated CYTOR and dysregulated HULC are perspective for differential diagnostics of liver cancers; whereas others demonstrated discordant results and cannot be considered as potential universal biomarkers for this purpose.

Role of Chemokines in the Biology of Cholangiocarcinoma

Cholangiocarcinoma (CCA), a heterogeneous tumor with poor prognosis, can arise at any level in the biliary tree. It may derive from epithelial cells in the biliary tracts and peribiliary glands and possibly from progenitor cells or even hepatocytes. Several risk factors are responsible for CCA onset, however an inflammatory milieu nearby the biliary tree represents the most common condition favoring CCA development. Chemokines play a key role in driving the immunological response upon liver injury and may sustain tumor initiation and development. Chemokine receptor-dependent pathways influence the interplay among various cellular components, resulting in remodeling of the hepatic microenvironment towards a pro-inflammatory, pro-fibrogenic, pro-angiogenic and pre-neoplastic setting. Moreover, once tumor develops, chemokine signaling may influence its progression. Here we review the role of chemokines in the regulation of CCA development and progression, and the modulation of angiogenesis, metastasis and immune control. The potential role of chemokines and their receptors as possible biomarkers and/or therapeutic targets for hepatobiliary cancer is also discussed.

Long non-coding RNA SCARNA2 induces cutaneous squamous cell carcinoma progression via modulating miR-342-3p expression

BACKGROUND

Long non-coding RNAs (lncRNAs) play important roles in the progression of tumors. However, the function and expression of SCARNA2 in cutaneous squamous cell carcinoma (cSCC) is still unreported.

METHODS

A quantitative polymerase chain reaction was applied to study the expression of SCARNA2 and miR-342-3p. Cell counting kit-8, flow cytometry and transwell assays were performed to study cell growth, cycle and cell invasion.

RESULTS

We found that SCARNA2 expression is up-regulated in cSCC cell lines and SCARNA2 expression is higher in cSCC tissues than in adjacent non-tumor specimens. Ectopic expression of SCARNA2 promoted cell growth, cell cycle and invasion in SCC13 cells. In addition, the data indicate that miR-342-3p expression is down-regulated in cSCC cell lines and miR-342-3p is down-regulated in cSCC tissues compared to adjacent non-tumor specimens. We showed that the SCARNA2 expression is negatively associated with miR-342-3p in cSCC. Moreover, we noted that SCARNA2 sponges miR-342-3p expression in cSCC cells. Overexpression of SCARNA2 suppressed the miR-342-3p expressed in SCC13 cells. We found that elevated expression of SCARNA2 promotes cell growth, cell cycle and invasion via regulating miR-342-3p expression in SCC13 cells.

CONCLUSIONS

These data suggest that SCARNA2 acts in an oncogenic role and may be a potential target for cSCC.

Long noncoding RNA ANRIL promotes the malignant progression of cholangiocarcinoma by epigenetically repressing ERRFI1 expression

Long noncoding RNAs (lncRNAs) have recently been verified to have significant regulatory functions in many types of human cancers. The lncRNA ANRIL is transcribed from the INK4b-ARF-INK4a gene cluster in the opposite direction. Whether ANRIL can act as an oncogenic molecule in cholangiocarcinoma (CCA) remains unknown. Our data show that ANRIL knockdown greatly inhibited CCA cell proliferation and migration in vitro and in vivo. According to the results of RNA sequencing analysis, ANRIL knockdown dramatically altered target genes associated with the cell cycle, cell proliferation, and apoptosis. By binding to a component of the epigenetic modification complex enhancer of zeste homolog 2 (EZH2), ANRIL could maintain lysine residue 27 of histone 3 (H3K27me3) levels in the promoter of ERBB receptor feedback inhibitor 1 (ERRFI1), which is a tumor suppressor gene in CCA. In this way, ERRFI1 expression was suppressed in CCA cells. These data verified the key role of the epigenetic regulation of ANRIL in CCA oncogenesis and indicate its potential as a target for CCA intervention.

Role of noncoding RNAs in cholangiocarcinoma (Review)

Cholangiocarcinoma (CCA) is a malignant tumour originating from biliary epithelial cells, and is increasing in incidence. Radical surgery is the main treatment. However, the pathogenesis of CCA is unclear. Noncoding RNAs (ncRNAs) are non‑protein‑coding RNAs produced by genomic transcription that include microRNAs (miRNAs), circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs). They play important roles in gene expression, epigenetic modification, cell proliferation, differentiation and reproduction. ncRNAs also serve key roles in cancer development. Numerous studies have been carried out on ncRNAs, and associated publications have shown that ncRNAs are closely associated with the physiological and pathological mechanisms of CCA. The findings of these studies can provide new insights into the diagnosis, treatment and prognosis of CCA. The present review summarizes the pathophysiological mechanisms of different types of ncRNAs, including miRNAs, circRNAs and lncRNAs in CCA, and their applications in the diagnosis and treatment of CCA.

LINC01410 promotes cell proliferation and migration of cholangiocarcinoma through modulating miR-124-3p/SMAD5 axis

BACKGROUND

Cholangiocarcinoma (CCA) is generally associated with high incidence and poor prognosis. Nowadays, increasing experimental data demonstrate that long non-coding RNA (lncRNA) plays an indispensable role in tumor occurrence. Nevertheless, the specific mechanism of lncRNA is not clear in CCA.

METHODS

The relative expressions of lncRNAs, miRNAs, and mRNAs were detected by real-time quantitative PCR (RT-qPCR). CCK8 and colony formation assays were applied to examine cell proliferation ability in CCA. Transwell assay was conducted to measure the migration and invasion capabilities of CCA cells. Nuclear and cytoplasmic separation assay was implemented to figure out the location of LINC01410. Luciferase reporter assay, RIP and RNA pull-down assays were applied to certify the molecular bindings. Western blot was applied to detect the protein level.

RESULTS

The high expression of LINC01410 was proved in CCA tissues and CCA cell lines. Also, CCA patients with high LINC01410 level presented poor prognosis. LINC01410 deficiency impeded cell proliferation, migration and invasion in HuCCT1 and RBE cell lines. What's more, LINC01410 interacted with miR-124-3p. Meanwhile, SMAD5 targeted and inhibited by miR-124-3p. SMAD5 expression was enhanced by LINC01410.

CONCLUSION

LINC01410 facilitates cell proliferation, migration and invasion through miR-124-3p/SMAD5 axis.

The construction and application of lentiviral overexpression vector of goat miR-204 in testis

The miRNA gene in DNA is first transcribed to Pri-miRNA, and then processed to Pre-miRNA, a stem-loop RNA segment (precursor) and further to miRNA which binds to mRNA by Dicer protein complex. It was confirmed that goat miR-204 could regulate the expressions of Sirt1 and the SSCs' (Spermatogonial Stem Cells) important genes Oct4 and Plzf, and inhibit the proliferation of dairy goat SSCs in vitro in our previous work. So, the research in vivo was needed next. In this study, the recombinant lentivirus vector pCDH-CMV-mir204-EF1-GreenPuro containing a goat chi-pri-mir-204 gene DNA segment was structured, and transfected into 293 T cells for packaged lentivirus, which then were injected into mouse seminiferous tubules. After 7 days, the goat miR-204 and the related genes such as Sirt1 and Plzf were detected in the mouse testis. This work laid a good foundation for further study of miR-204 biological function in vivo.

Nomogram based on inflammatory indices for differentiating intrahepatic cholangiocarcinoma from hepatocellular carcinoma

Objective

To establish nomogram based on inflammatory indices for differentiating intrahepatic cholangiocarcinoma (ICC) from hepatocellular carcinoma (HCC).

Methods

A cohort of 422 patients with HCC or ICC hospitalized at Xiangya Hospital between January 2014 and December 2018 was included in the study. Univariate and multivariate analysis was performed to identify the independent differential factors. Through combining these independent differential factors, a nomogram was established for differential diagnosis between ICC and HCC. The accuracy of nomogram was evaluated by using receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA). The results were validated using a prospective study on 98 consecutive patients operated on from January 2019 to November 2019 at the same institution.

Results

Sex (OR = 9.001, 95% CI: 3.268‐24.792, P < .001), hepatitis (OR = 0.323, 95% CI: 0.121‐0.860, P = .024), alpha‐fetoprotein (AFP) (OR = 0.997, 95% CI: 0.995‐1.000, P = .046), carbohydrate antigen 19‐9 (CA199) (OR = 1.016, 95% CI: 1.007‐1.025, P < .001), and aspartate transaminase‐to‐neutrophil ratio index (ANRI) (OR = 0.904, 95% CI: 0.843‐0.969, P = .004) were the independent differential factors for ICC. Nomogram was established with well‐fitted calibration curves through incorporating these 5 factors. Comparing model 1 including gender, hepatitis, AFP, and CA199 (C index = 0.903, 95% CI: 0.849‐0.957) and model 2 enrolling AFP and CA199 (C index = 0.850, 95% CI: 0.791‐0.908), the nomogram showed a better discrimination between ICC and HCC, with a C index of 0.920 (95% CI, 0.872‐0.968). The results were consistent in the validation cohort. DCA also confirmed the conclusion.

Conclusion

A nomogram was established for the differential diagnosis between ICC and HCC preoperatively, and better therapeutic choice would be made if it was applied in clinical practice.

Long non-coding RNA MALAT1 activates autophagy and promotes cell proliferation by downregulating microRNA-204 expression in gastric cancer

Gastric cancer (GC) is one of the major diseases that threaten human health. Although the development of novel drugs has significantly improved the efficacy of GC chemotherapy, the 5-year survival rate of patients with GC remains unsatisfactory. In the present study, the role and mechanism of the long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in GC proliferation was investigated. Clinical specimens and cancer cells were analyzed by western blotting or immunofluorescence. Reverse transcription-quantitative polymerase chain reaction analysis of 57 paired GC and non-tumorous tissues revealed elevated expression of MALAT1 in GC tissues compared with controls. In addition, increased MALAT1 was associated with elevated levels of microtubule-associated protein 1 light chain 3β (LC3B) and antigen Ki67, which are autophagy and proliferation markers, respectively. MTT and colony formation assay results demonstrated that MALAT1 promoted GC cell proliferation. To the best of our knowledge, the present study was the first to demonstrate that upregulated MALAT1 was associated with increased autophagy activation in GC tissues. Furthermore, this study reported that MALAT1 increased cell proliferation and enhanced autophagy activation in GC cells. In addition, the results revealed that MALAT1 inhibited microRNA (miR)-204 expression in GC cells. The present study also demonstrated that miR-204 repressed autophagy through the downregulation of LC3B and transient receptor potential melastatin 3 expression in GC cells. These results indicated that MALAT1 activated autophagy and promoted cell proliferation by downregulating miR-204 expression in GC.

Metastasis Associated Lung Adenocarcinoma Transcript 1: An update on expression pattern and functions in carcinogenesis

The Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is among long non-coding RNAs (lncRNAs) which has disapproved the old term of "junk DNA" which was used for majority of human genome which are not transcribed to proteins. An extensive portion of literature points to the fundamental role of this lncRNA in tumorigenesis process of diverse cancers ranging from solid tumors to leukemia. Being firstly identified in lung cancer, it has prognostic and diagnostic values in several cancer types. Consistent with the proposed oncogenic roles for this lncRNA, most of studies have shown up-regulation of MALAT1 in malignant tissues compared with non-malignant/normal tissues of the same source. However, few studies have shown down-regulation of MALAT1 in breast cancer, endometrial cancer, colorectal cancer and glioma. In the current study, we have conducted a comprehensive literature search and provided an up-date on the role of MALAT1 in cancer biology. Our investigation underscores a potential role as a diagnostic/prognostic marker and a putative therapeutic target for MALAT1.

Up-regulated LncRNA-ATB regulates the growth and metastasis of cholangiocarcinoma via miR-200c signals

Background and objective

Cholangiocarcinoma (CCA) is a highly aggressive neoplasm featured with regional invasiveness and distant metastasis, which often present a phenotype of epithelial–mesenchymal transition (EMT). Long non-coding RNAs (LncRNAs) are dysregulated during carcinogenesis, and up-regulated LncRNA-activated by TGF-β (Lnc-ATB) supports tumor growth and metastasis via tumor suppressor microRNA 200 (miR-200). However, the role of Lnc-ATB in CCA is unclear.

Methods

CCA tissues and non-cancer tissues (n=30) were used to determine the Lnc-ATB and miR-200a/b/c levels. The functions and mechanisms of Lnc-ATB/miR-200 pathway were determined by knockdown of Lnc-ATB via siRNAs in vitro and in vivo.

Results

CCA tissues have increased Lnc-ATB and reduced miR-200a/b/c levels, but the down-regulated miR-200c was most prominent. Up-regulated Lnc-ATB significant negatively correlated with miR-200c and predicted advanced TNM stage and more lymph node metastasis of CCA patients. Knockdown of Lnc-ATB in two CCA cell lines HuCCT1 and RBE increased miR-200c levels. The luciferase reporter assay further confirmed the direct binding site of miR-200c in Lnc-ATB. Inhibition of Lnc-ATB significantly impaired cell vitality and induced apoptosis and G0/G1 arrest, which, however, was rescued by miR-200c inhibitor. The ability of migration of CCA cells was also up-regulated by Lnc-ATB but was suppressed by miR-200c. Mechanistically, the cell cycle-related CCND1/CDK2, apoptosis-related BCL-2/caspase-3 and EMT-related E-cadherin/ZEB1/2 were regulated by Lnc-ATB via miR-200c. Knockdown of Lnc-ATB in vivo up-regulated miR-200c signals to inhibit tumor growth with decreased PCNA expression in tumor tissues, which was restored by miR-200c inhibition.

Conclusion

Overexpressed Lnc-ATB functioned as an oncogene for CCA growth and metastasis via miR-200 signals.

Long noncoding RNA LINC00339 promotes laryngeal squamous cell carcinoma cell proliferation and invasion via sponging miR-145

Laryngeal squamous cell carcinoma (LSCC) is a very common neoplasm of the head and neck in the world. Long noncoding RNAs play key roles in cell infiltration, fate, apoptosis, and invasion. However, the functional role and expression of LINC00339 remains unclear in LSCC. In this study, we showed that the expression level of LINC00339 was upregulated in LSCC tissues and cell lines. LINC00339 silencing suppressed the proliferation, invasion, and epithelial-mesenchymal transition (EMT) progression of LSCC cells. In addition, we showed that LINC00339 acted as a sponge of miR-145, and LINC00339 silencing promoted the expression of miR-145 in Hep2 cell. Furthermore, the expression of miR-145 was lower in LSCC tissues than in their paired normal samples and the miR-145 expression level was negatively correlated with LINC00339 expression in LSCC tissues. The knockdown of miR-145 promoted the proliferation, invasion, and EMT progression of LSCC cells. Finally, we indicated that LINC00339 silencing inhibited the proliferation, invasion, and EMT progression of LSCC cells by suppressing the miR-145 expression. These data suggested that LINC00339 acted as an oncogene in the development of LSCC, partly by regulating the miR-145 expression.

YAP1-induced MALAT1 promotes epithelial-mesenchymal transition and angiogenesis by sponging miR-126-5p in colorectal cancer

Yes-associated protein 1 (YAP1) exerts significant effects in various malignancies. However, the oncogenic role of YAP1 remains controversial, and the mechanism by which YAP1 regulates non-coding RNAs is still largely unknown. The present study aimed to assess the effect of YAP1 on the malignant behaviors of colorectal carcinoma (CRC) and explore the underlying regulatory mechanism of the YAP1-MALAT1-miR-126-5p axis. YAP1 was highly expressed in CRC tissues as assessed by GSE20916 and its expression was negatively correlated with overall survival in 83 CRC cases. Meanwhile, YAP1 promoted proliferation, invasion, and migration in colon cancer cells, in vitro and in vivo. MALAT1 was obviously expressed, with differential expression of 11 lncRNAs in HCT116 cells after transfection with siYAP1 or si-Ctl. Based on bioinformatics prediction, immunoprecipitation (IP), and chromatin immunoprecipitation (ChIP), the interaction of YAP1 with TCF4/β-catenin was regulated by MALAT1. Bioinformatics prediction, dual luciferase assay, RNA-IP, and RNA pull-down assay demonstrated that YAP1-induced MALAT1 promoted the expression of metastasis-associated molecules such as VEGFA, SLUG, and TWIST, by sponging miR-126-5p in CRC. These findings indicated that the YAP1-MALAT1-miR-126-5p axis could control angiogenesis and epithelial-mesenchymal transition in CRC, providing potential biomarkers and therapeutic targets for CRC.

Functions and roles of long noncoding RNA in cholangiocarcinoma

Cholangiocarcinoma (CCA) is one of the most fatal cancers in humans, with a gradually increasing incidence worldwide. The efficient diagnostic and therapeutic measures for CCA to reduce mortality are urgently needed. Long noncoding RNAs (lncRNAs) may provide the potential diagnostic and therapeutic option for suppressing the CCA development. LncRNAs are a type of non-protein-coding RNAs, which are larger than 200 nucleotides in length. Increasing evidence reveals that lncRNAs exhibit critical roles in the carcinogenesis and development of CCA. Deregulation of lncRNAs impacts the proliferation, migration, invasion, and antiapoptosis of CCA cells by multiple sophisticated mechanisms. Consequently, lncRNAs likely represent promising biomarkers or intervention targets of CCA. In this review, we summarize current studies regarding the biological functions and regulatory mechanisms of diverse lncRNAs in CCA.

lncRNAs as potential molecular biomarkers in the clinicopathology and prognosis of cholangiocarcinoma: a systematic review and meta-analysis

Background

Cholangiocarcinoma (CCA) is the second most common fatal primary hepatobiliary malignant carcinoma, characterized by early invasion and extremely poor outcomes. It is therefore necessary to identify a novel biomarker to better diagnose CAA and predict its prognosis. Recently, emerging evidence has revealed that some lncRNAs play an important role in the tumorigenesis and progression of CAA. In order to support this search for novel diagnostic and prognostic biomarkers for CAA, we conducted a meta-analysis to analyze the published association between lncRNA expression and its clinical value in CAA.

Methods

Eligible studies were pooled and analyzed according to our inclusion and exclusion criteria after a comprehensive literature search. Stata 14.0 software was used to analyze the data from relevant studies and to construct a forest plot. Different effect sizes were selected for the meta-analysis.

Results

In total, 24 publications were included in this meta-analysis. After review of their full-text, 16 articles studied the association between lncRNAs and clinicopathological characteristics, 2 discussing diagnosis and 16 discussing prognosis. Our results showed that overexpression of CCAT1 was significantly correlated with tumor stage (I + II vs III + IV) (OR, 4.99; 95% CI 2.77–8.99; P<0.001) and lymph node metastasis in CCA (OR, 4.75; 95% CI 2.65–8.52; P<0.001). Furthermore, elevated CCAT lncRNA family expression predicted a shorter overall survival (HR, 2.09; 95% CI 1.17–3.00; P<0.001), especially CCAT2. Upregulation of CCAT2 was also obviously associated with tumor stage in CCA (OR, 5.29; 95% CI 2.64–10.58; P=0.001).

Conclusion

This is the first meta-analysis to assess the relationship between expression of lncRNAs and the clinical values of patients with CCA. lncRNAs can function as potential molecular biomarkers of the clinicopathology and prognosis of CCA.

Long non-coding RNA MALAT1 regulates BLCAP mRNA expression through binding to miR-339-5p and promotes poor prognosis in breast cancer

The human genome transcribes a large amount of non-coding RNAs, including long non-coding RNAs (lncRNAs) and microRNAs. LncRNAs and microRNAs have been shown to play a critical regulatory role in tumorigenesis and progression. Competitive endogenous RNAs (ceRNAs) affect other RNAs transcription through competitively binding to common microRNAs (miRNAs). MALAT1 is a typical lncRNA that is markedly up-regulated in breast cancer. However, current understanding of the involvement of MALAT1 in breast cancer development and prognosis remains unclear. In the present study, the expression of MALAT1 in clinical samples of breast cancer tissues was found to be significantly up-regulated that was consistent with the result based on the dataset of the Cancer Genome Atlas (TCGA) at cBioportal. A negative correlation between overall survival and the expression of MALAT1 was statistically significant in the group of diagnosis age below 60 or in the group of infiltrating ductal carcinoma analyzed by TCGA database, which declared that MALAT1 might be a potentially useful prognostic factor. Furthermore, the combination of bioinformatics prediction with experimental verifications indicated that lncRNA MALAT1 can regulate BLCAP mRNA expression through binding to miR-339-5p.

The Advancement of Long Non-Coding RNAs in Cholangiocarcinoma Development

Cholangiocarcinoma (CCA) is a malignancy with increasing incidence in recent years. CCA patients are usually diagnosed at advanced stage due to lack of apparent symptoms and specifically diagnostic markers. Nowadays, surgical removal is the only effective method for CCA whereas overall 5-year-survival rate keeps around 10%. Long-noncoding RNA (lncRNA), a subtype of noncoding RNA, is widely studied to be abnormally expressed in multiple cancers including CCA. LncRNA can promote proliferation, migration, invasion and inhibit apoptosis of CCA. Moreover, lncRNA is negatively correlated with the prognosis of CCA. LncRNA may contribute to the development of CCA via modulating gene transcription, sponging microRNA, regulating CCA-related signaling pathways or protein expression. LncRNA is thought to be potential diagnostic markers and therapeutic targets for CCA.

Long noncoding RNA NEAT1 promotes the growth of human retinoblastoma cells via regulation of miR-204/CXCR4 axis

Retinoblastoma (RB) is an aggressive eye cancer of infancy and childhood with high mortality. Studies have shown that long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) is closely related to the progression of multiple cancers. However, its role in RB remains unknown. This study aimed to investigate the role and underlying mechanism of NEAT1 in RB. We first detected the expression of NEAT1 in human RB tissues and cell lines. The effects of NEAT1 on the proliferation, migration, and apoptosis of RB cells were analyzed by loss-of-function. The underlying mechanism of NEAT1 in RB was mainly focused on the microRNA 204/C-X-C chemokine receptor type 4 (miR-204/CXCR4) axis. In addition, the role and mechanism of NEAT1 in RB were further evaluated in a mouse xenograft tumor model. We found NEAT1 and CXCR4 expression levels were elevated, whereas miR-204 expression was decreased in RB tissues and cells. Downregulation of NEAT1 significantly decreased the proliferation and migration but promoted the apoptosis of RB cells. NEAT1 functioned as a competing endogenous RNA for miR-204 to regulate CXCR4 expression. Knockdown of NEAT1 suppressed the tumor volume, tumor weight, and CXCR4 expression, whereas increased miR-204 expression in mice. In conclusion, NEAT1 promotes the development of RB via miR-204/CXCR4 axis, which provides a new target for the treatment of RB disease.

Long Non-coding RNA PVT1 Promotes Cell Proliferation and Migration by Silencing ANGPTL4 Expression in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most common biliary tract malignancy, with a low survival rate and limited treatment options. Long non-coding RNAs (lncRNAs) have recently been verified to have significant regulatory functions in many kinds of human cancers. It was discovered in this study that the lncRNA PVT1, whose expression is significantly elevated in CCA, could be a molecular marker of CCA. Experiments indicated that PVT1 knockdown greatly inhibited cell migration and proliferation in vitro and in vivo. According to RNA sequencing (RNA-seq) analysis, PVT1 knockdown dramatically influenced target genes associated with cell angiogenesis, cell proliferation, and the apoptotic process. RNA immunoprecipitation (RIP) analysis demonstrated that, by binding to epigenetic modification complexes (PRC2), PVT1 could adjust the histone methylation of the promoter of ANGPTL4 (angiopoietin-like 4) and, thus, promote cell growth, migration, and apoptosis progression. The data verified the significant functions of PVT1 in CCA oncogenesis, and they suggested that PVT1 could be a target for CCA intervention.

Upregulation of gastric adenocarcinoma predictive long intergenic non-coding RNA promotes progression and predicts poor prognosis in perihilar cholangiocarcinoma

Perihilar cholangiocarcinoma (PHCC) is one of the most aggressive and complex types of cancer with a poor survival. Despite advances in PHCC diagnosis and treatment, the biology of this tumor remains poorly understood. Recent studies have suggested long non-coding RNAs (lncRNAs) as crucial determinants of cancer progression. However, the role of lncRNAs in PHCC is rarely reported and the function of gastric adenocarcinoma predictive long intergenic non-coding RNA (GAPLINC) in PHCC has yet to be elucidated. The present study observed a significant upregulation of GAPLINC in PHCC cell lines and clinical specimens (P<0.05). Furthermore, by comparing clinicopathological characteristics with expression data, high GAPLINC expression was revealed to be associated with the T stage (P=0.013), N stage (P<0.001) and Tumor-Node-Metastasis stage (P<0.001) of PHCC. Furthermore, Kaplan-Meier analysis demonstrated that GAPLINC expression was associated with poor overall survival and progression-free survival rates in PHCC. Furthermore, univariate and multivariate COX regression analyses identified high GAPLINC expression as a risk factor of a poor prognosis in PHCC. GAPLINC upregulation promoted the migration and invasion of PHCC cells in Transwell and Matrigel assays, respectively, while GAPLINC deficiency inhibited PHCC cell metastasis. Furthermore, PHCC cells with GAPLINC overexpression exhibited markedly increased proliferation ability in a Cell Counting kit-8 assay. However, GAPLINC interference significantly suppressed cell proliferation. In conclusion, GAPLINC may promote PHCC progression and may serve as a potential prognostic marker and therapeutic target of PHCC.

Epigenetic silencing of tumor suppressor gene CDKN1A by oncogenic long non-coding RNA SNHG1 in cholangiocarcinoma

Cholangiocarcinoma (CCA) is the as the most frequently observed biliary tract malignancy, which has low survival rate in addition to constrained treatment options; nevertheless, the fundamental molecular phenomenon underlying malignant progression of CCA is quite ambiguous. Recently long non-coding RNAs (lncRNAs) have been found to have significant regulatory functions in several human cancers. Herein, we have figured out that lncRNA SNHG1, with substantially enhanced expression in CCA, is capable of acting as the oncogenic molecule of CCA. As revealed by our data, SNHG1 knockdown extensively inhibited CCA cell migration as well as proliferation in vitro and in vivo. In addition, in accordance with the findings of the RNA-Seq analysis, SNHG1 knockdown exhibited a significant impact on the target genes that were linked to cell migration and regulation of cell proliferation, in addition to the apoptotic phenomenon. In a mechanistic manner, we also showed that SNHG1 bound to the histone methyltransferase enhancer of the zeste homolog 2 (EZH2, which is regarded as the catalytic subunit of the polycomb repressive complex 2 (PRC2), which is an extremely conserved protein complex regulating gene expression with the help of methylating lysine 27 on histone H3), specifying the histone alteration pattern on the target genes, including CDKN1A, and, as a result, altered the CCA cell biology. These data verified a major function of the epigenetic regulation of SNHG1 in CCA oncogenesis, in addition to its likely function as a target for CCA interruption.

SP1-induced upregulation of lncRNA SPRY4-IT1 exerts oncogenic properties by scaffolding EZH2/LSD1/DNMT1 and sponging miR-101-3p in cholangiocarcinoma

Background

Accumulating evidence has indicated that long non-coding RNAs (lncRNAs) behave as a novel class of transcription products during multiple cancer processes. However, the mechanisms responsible for their alteration in cholangiocarcinoma (CCA) are not fully understood.

Methods

The expression of SPRY4-IT1 in CCA tissues and cell lines was determined by RT-qPCR, and the association between SPRY4-IT1 transcription and clinicopathologic features was analyzed. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were performed to explore whether SP1 could bind to the promoter region of SPRY4-IT1 and activate its transcription. The biological function of SPRY4-IT1 in CCA cells was evaluated both in vitro and in vivo. ChIP, RNA binding protein immunoprecipitation (RIP) and luciferase reporter assays were performed to determine the molecular mechanism of SPRY4-IT1 in cell proliferation, apoptosis and invasion.

Results

SPRY4-IT1 was abnormally upregulated in CCA tissues and cells, and this upregulation was correlated with tumor stage and tumor node metastasis (TNM) stage in CCA patients. SPRY4-IT1 overexpression was also an unfavorable prognostic factor for patients with CCA. Additionally, SP1 could bind directly to the SPRY4-IT1 promoter region and activate its transcription. Furthermore, SPRY4-IT1 silencing caused tumor suppressive effects via reducing cell proliferation, migration and invasion; inducing cell apoptosis and reversing the epithelial-to-mesenchymal transition (EMT) process in CCA cells. Mechanistically, enhancer of zeste homolog 2 (EZH2) along with the lysine specific demethylase 1 (LSD1) or DNA methyltransferase 1 (DNMT1) were recruited by SPRY4-IT1, which functioned as a scaffold. Importantly, SPRY4-IT1 positively regulated the expression of EZH2 through sponging miR-101-3p.

Conclusions

Our data illustrate how SPRY4-IT1 plays an oncogenic role in CCA and may offer a potential therapeutic target for treating CCA.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0747-x) contains supplementary material, which is available to authorized users.

Oncogenic long noncoding RNA MALAT1 and HCV-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. The oncogenic function of the long non-coding RNA; metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in HCC remains unclear. We aimed to evaluate MALAT1 serum expression profile in HCC and explore its relation to the clinicopathological features. Quantitative Real Time-Polymerase Chain Reaction was applied in 70 cohorts (30 HCC, 20 HCV, 20 controls). Further meta-analysis of clinical studies and in vitro validated experiments was employed. Serum MALAT1 showed area under the curve of 0.79 and 0.70 to distinguish patients with cancer from normal and cirrhotic individuals at fold change of 1.0 and 1.26, respectively. Expression level was significantly higher in males (P <0.001) and patients with massive ascites (P = 0.005). Correlation analysis showed positive correlation of MALAT1 with total bilirubin (r = 0.456, P <0.001) and AST (r = 0.280, P = 0.019), and negative correlation with the hemoglobin level (r = 0.312, P = 0.009). Meta-analysis showed that the over-expressed MALAT1 was linked to tumor number [Cohen's d = 0.450, 95% CI (0.21 to 0.68)], clinical stage [Cohen's d = 0.048, 95% CI (-0.83 to 0.74)], and AFP level [Cohen's d = 0.354, 95% CI (0.1 to 0.57)]. In silico data analysis and systematic review confirmed MALAT1 oncogenic function in cancer development and progression. In conclusion, circulatory MALAT1 might represent a putative non-invasive prognostic biomarker indicating worse liver failure score in HCV-related HCC patients with traditional markers. Large-scale verification is warranted in future studies.