Upregulated long noncoding RNA PANDAR predicts an unfavorable prognosis and promotes tumorigenesis in cholangiocarcinoma

The Diagnostic and Prognostic Potentials of Non-Coding RNA in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare biliary tract tumor with high malignancy. CCA is the second most common primary hepatobiliary cancer after hepatocarcinoma. Despite its rarity, the incidence of CCA is steadily increasing globally. Most patients with CCA are asymptomatic in the early stages, resulting in a late-stage diagnosis and poor prognosis. Finding reliable biomarkers is essential to improve CCA's early diagnosis and survival rate. Non-coding RNAs (ncRNAs) are non-protein coding RNAs produced by genomic transcription. This includes microRNAs, long non-coding RNAs, and circular RNAs. ncRNAs have multiple functions in regulating gene expression and are crucial for maintaining normal cell function and developing diseases. Many studies have shown that aberrantly expressed ncRNAs can regulate the occurrence and development of CCA. ncRNAs can be easily extracted and detected through tumor tissue and liquid biopsies, representing a potential tool for diagnosing and prognosis CCA. This review will provide a detailed update on the diagnostic and prognostic potentials of lncRNAs and cirRNAs as biomarkers in CCA.

Harnessing the supremacy of MEG3 LncRNA to defeat gastrointestinal malignancies

Evidence suggests that long non-coding RNAs (lncRNAs) play a pivotal role in the carcinogenesis and progression of various human malignancies including gastrointestinal malignancies. This comprehensive review reports the functions and mechanisms of the lncRNA maternally expressed gene 3 (MEG3) involved in gastrointestinal malignancies. It summarizes its roles in mediating the regulation of cellular proliferation, apoptosis, migration, invasiveness, epithelial-to-mesenchymal transition, and drug resistance in several gastrointestinal cancers such as colorectal cancer, gall bladder cancer, pancreatic cancer, gastric cancer, esophageal cancer, cholangiocarcinoma, gastrointestinal stromal tumors and most importantly, hepatocellular carcinoma. In addition, the authors briefly highlight its implicated mechanistic role and interactions with different non-coding RNAs and oncogenic signaling cascades. This review presents the rationale for developing non coding RNA-based anticancer therapy via harnessing the power of MEG3 in gastrointestinal malignancies.

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.

The long non-coding RNA PANDAR regulates cell proliferation and epithelial-to-mesenchymal transition in glioma

Glioma is one of the most aggressive intracranial tumors in the central nervous system. The long non-coding RNA P21 associated ncRNA DNA damage activated (PANDAR) has been reported to be an oncogene or tumor suppressor in several cancers. However, the prognostic value and biological function of PANDAR in glioma have not been described. Here, we report that expression of PANDAR is significantly up-regulated in glioma tissues and cell lines. PANDAR expression was correlated with tumor size (p=0.044) and World Health Organization (WHO) grades (p=0.005), as shown by chi-squared test. Moreover, significant upregulation of PANDAR was found to correlate with poor prognosis in glioma, as shown using Kaplan-Meier method and Cox multivariate survival analysis. Furthermore, PANDAR knockdown suppressed cell proliferation, G1/S transition, migration and invasion, and promoted apoptosis in glioma cell lines (U251 and U87). PANDAR knockdown decreased expression of CDK4, Bcl-2, N-cadherin and Vimentin, but increased E-cadherin expression in glioma cells. In conclusion, our data suggest PANDAR as a potential prognostic biomarker and therapeutic candidate for glioma.

Clinical relevance of biomarkers in cholangiocarcinoma: critical revision and future directions

Cholangiocarcinoma (CCA) is a malignant tumour arising from the biliary system. In Europe, this tumour frequently presents as a sporadic cancer in patients without defined risk factors and is usually diagnosed at advanced stages with a consequent poor prognosis. Therefore, the identification of biomarkers represents an utmost need for patients with CCA. Numerous studies proposed a wide spectrum of biomarkers at tissue and molecular levels. With the present paper, a multidisciplinary group of experts within the European Network for the Study of Cholangiocarcinoma discusses the clinical role of tissue biomarkers and provides a selection based on their current relevance and potential applications in the framework of CCA. Recent advances are proposed by dividing biomarkers based on their potential role in diagnosis, prognosis and therapy response. Limitations of current biomarkers are also identified, together with specific promising areas (ie, artificial intelligence, patient-derived organoids, targeted therapy) where research should be focused to develop future biomarkers.

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.

Prognostic and Predictive Molecular Markers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary liver cancer and subsumes a heterogeneous group of malignant tumors arising from the intra- or extrahepatic biliary tract epithelium. A rising mortality from CCA has been reported worldwide during the last decade, despite significant improvement of surgical and palliative treatment. Over 50% of CCAs originate from proximal extrahepatic bile ducts and constitute the most common CCA entity in the Western world. Clinicopathological characteristics such as lymph node status and poor differentiation remain the best-studied, but imperfect prognostic factors. The identification of prognostic molecular markers as an adjunct to traditional staging systems may not only facilitate the selection of patients who would benefit the most from surgical, adjuvant or palliative treatment strategies, but may also be helpful in defining the aggressiveness of the disease and identifying patients at high-risk for tumor recurrence. The purpose of this review is to provide an overview of currently known molecular prognostic and predictive markers and their role in CCA.

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.

Integrated Analysis of a Competing Endogenous RNA Network Reveals a Prognostic lncRNA Signature in Bladder Cancer

Long non-coding RNAs (lncRNAs) act as competing endogenous RNAs (ceRNAs) to regulate mRNA expression through sponging microRNA in tumorigenesis and progression. However, following the discovery of new RNA interaction, the differentially expressed RNAs and ceRNA regulatory network are required to update. Our study comprehensively analyzed the differentially expressed RNA and corresponding ceRNA network and thus constructed a potentially predictive tool for prognosis. “DESeq2” was used to perform differential expression analysis. Two hundred and six differentially expressed (DE) lncRNAs, 222 DE miRNAs, and 2,463 DE mRNAs were found in this study. The lncRNA-mRNA interactions in the miRcode database and the miRNA-mRNA interactions in the starBase, miRcode, and mirTarBase databases were searched, and a competing endogenous RNA (ceRNA) network with 186 nodes and 836 interactions was subsequently constructed. Aberrant expression patterns of lncRNA NR2F1-AS1 and lncRNA AC010168.2 were evaluated in two datasets (GSE89006, GSE31684), and real-time polymerase chain reaction was also performed to validate the expression pattern. Furthermore, we found that these two lncRNAs were independent prognostic biomarkers to generate a prognostic lncRNA signature by univariate and multivariate Cox analyses. According to the lncRNA signature, patients in the high-risk group were associated with a poor prognosis and validated by an external dataset. A novel genomic-clinicopathologic nomogram to improve prognosis prediction of bladder cancer was further plotted and calibrated. Our study deepens the understanding of the regulatory ceRNA network and provides an easy-to-do genomic-clinicopathological nomogram to predict the prognosis in patients with bladder cancer.

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.

Long Non-Coding RNAs in Biliary Tract Cancer-An Up-to-Date Review

The term long non-coding RNA (lncRNA) describes non protein-coding transcripts with a length greater than 200 base pairs. The ongoing discovery, characterization and functional categorization of lncRNAs has led to a better understanding of the involvement of lncRNAs in diverse biological and pathological processes including cancer. Aberrant expression of specific lncRNA species was demonstrated in various cancer types and associated with unfavorable clinical characteristics. Recent studies suggest that lncRNAs are also involved in the development and progression of biliary tract cancer, a rare disease with high mortality and limited therapeutic options. In this review, we summarize current findings regarding the manifold roles of lncRNAs in biliary tract cancer and give an overview of the clinical and molecular consequences of aberrant lncRNA expression as well as of underlying regulatory functions of selected lncRNA species in the context of biliary tract cancer.

Upregulated Long Noncoding RNA LINC01234 Predicts Unfavorable Prognosis for Colorectal Cancer and Negatively Correlates With KLF6 Expression

Background

LINC01234, a long noncoding RNA (lncRNA), is overexpressed in several cancers, including colorectal cancer (CRC). We investigated the role of LINC01234 in CRC development and confirmed its correlation with Krüppel-like factor 6 (KLF6), a tumor suppressor gene that is dysregulated in CRC.

Methods

We tested mRNA levels using quantitative reverse transcription PCR (qRT-PCR). Tissue samples from patients with CRC, inflammatory bowel disease (IBD), hyperplastic polyp, and adenoma were included. Correlations between clinicopathological parameters, overall survival (OS) rate, and LINC01234 were analyzed using Kruskal-Wallis H test. Additionally, cell proliferation, apoptosis, and tumor formation in nude mice were tested to investigate the mechanism of LINC01234. Western blotting was used to determine protein levels.

Results

LINC01234 expression was significantly upregulated in CRC tissues and CRC cell lines than in non-tumor tissues and normal epithelial cells, respectively. LINC01234 was associated with high tumor stage, larger tumor size, and metastasis. Patients with higher LINC01234 expression showed reduced OS. Cell proliferation was inhibited by LINC01234 knockdown, whereas apoptosis was enhanced. Mice injected with SW480 cells with LINC01234 knockdown displayed decreased tumor volume, weight, and Ki-67 levels compared with those injected with control cells. KLF6 was negatively regulated by LINC01234. Overexpression of KLF6 showed effects similar to those observed following LINC01234 knockdown on cell proliferation and apoptosis.

Conclusions

LINC01234 could be a prognostic biomarker in CRC patients. Upregulation of LINC01234 in CRC promotes tumor development through negative regulation of KLF6.

Inhibition of lncRNA PANDAR reduces cell proliferation, cell invasion and suppresses EMT pathway in breast cancer

BACKGROUND

The PANDAR, a novel identified long non-coding RNA, is previously reported to function as oncogene in various cancers including breast cancer. the study aims to explore the role of lncRNA PANDAR for cell proliferation and invasion of breast cancer, and its underlying mechanism.

METHODS

The expression of lncRNA PANDAR in 65 pairs of breast cancer tissues and adjacent normal tissues was detected by quantitative Real-time polymerase chain reaction (qRT-PCR) assay. The association between lncRNA PANDAR expression and clinical factors of breast cancer was analyzed. Cell proliferation, cell colony formation and cell invasion assays were performed to detect the effects of lncRNA PANDAR expression tumor proliferation and invasion abilities. The western blot analysis was also performed to detected the EMT related makers expression of E-cadherin, Vimentin, MMP2 and MMP9.

RESULTS

We demonstrated that lncRNA PANDAR expression was higher in breast cancer tissues and cells compared with adjacent normal tissues and the normal mammary epithelial cell line, respectively. Higher lncRNA PANDAR expression positively associated with lymph node metastasis and advanced clinical stage in patients. In vitro, we demonstrated that knockdown of lncRNA PANDAR significantly suppressed cell proliferation, cell colony formation and cell invasion ability in breast cells. Furthermore, we verified that knockdown of lncRNA PANDAR dramatically inhibited cell epithelial-mesenchymal transition (EMT) pathway by downregulating Vimentin, MMP2 and MMP9 expression, but upregulating E-cadherin expression in breast cancer.

CONCLUSIONS

Our results proved that PANDAR may serve as potential target of breast cancer treatment.

Prognostic and Clinicopathological Significance of Long Non-coding RNA PANDAR Expression in Cancer Patients: A Meta-Analysis

Background: Long non-coding RNA PANDAR is an emerging non-coding RNA mapping to 6p21.2. It underlies metastatic progression and chromosomal instability in a variety of cancers. Despite the fact that recent studies have revealed that lncRNA PANDAR may be a potential prognostic biomarker for patients with cancer, there has still been controversy on the prognostic value of PANDAR. Methods: Databases of PubMed, Embase, SinoMed, and Web of Science were carefully searched and the literature which investigated the prognostic value of PANDAR expression among human cancers was collected for further analysis. Odds ratios (ORs) or hazards ratios (HRs) with 95% confidence intervals (CIs) were pooled to estimate the relation between PANDAR expression and survival or clinicopathological characteristics of cancer patients. Results: There were 13 eligible studies in total, with 1,465 patients enlisted in this meta-analysis. All the eligible studies complied with the case-control study. The outcome showed that the elevated expression level of PANDAR was significantly related to poor overall survival (OS) (pooled HR 1.72, 95%CI 1.14-2.60). However, high or low expression of PANDAR did not differ in the prediction of event-free survival (EFS). Moreover, we discovered that high PANDAR expression was closely related to decreased OS in colorectal cancer (pooled HR 3.43, 95%CI 2.06-5.72) and reduced expression level of PANDAR was markedly related to poor OS (pooled HR 0.65, 95%CI 0.45-0.88) in non-small cell lung cancer. However, the expression level of PANDAR had no significant association with OS in renal cell carcinoma (pooled HR 1.19, 95%CI 0.56-2.50). Moreover, after analysis, we discovered that the high expression level of PANDAR was associated closely with the depth of invasion (pooled OR 3.95, 95%CI 2.36-6.63), lymph node metastasis (pooled OR 1.92, 95%CI 0.93-3.98), tumor stage (pooled OR 2.05, 95%CI 0.99-4.27), and distant metastasis (pooled OR 2.87, 95%CI 1.60-5.16). Conclusions: Our study revealed that increased PANDAR expression may serve as an adverse prognostic biomarker for cancer patients, thus helping the clinical decision-making process.

LncRNA LUCAT1 as a novel prognostic biomarker for patients with papillary thyroid cancer

In recent years, long non-coding RNAs have emerged as a novel class of regulators of cancer biological processes. While they are dysregulated in many cancer types, little is known about their expression and functional profiles. This study has been focused on the determination of the role of a specific lncRNA in papillary thyroid cancer. Quantitative reverse transcription PCR was performed to detect the expression levels of 84 lncRNAs in 61 papillary thyroid carcinoma tissues and their adjacent non-tumor tissues. The highest fold-change was obtained for lung cancer associated transcript 1 LUCAT1, and thus, this study determines the expression and biological implication of lncRNA LUCAT1 through different in vitro and ex vivo approaches in this tumor. LUCAT1 was specifically located at the cell nucleus in tumoral regions of patient tissues. Furthermore, LUCAT1 knockdown significantly reduced both cell proliferation and invasion ex vivo and induced cell-cycle arrest and apoptosis. These facts were corroborated by an enhanced expression of P21, P57, P53 and BAX, and a reduced expression of EZH2 and HDAC1. In addition, a significant decrease was observed on DNMT1 and NRF2 genes, helping to clarify the role of LUCAT1 on PTC. Our study reveals the involvement of LUCAT1 in PTC development, through acting in cell-cycle regulation, proliferation, epigenetic modifications through LUCAT1/ CDK1/ EZH2/ P57/ P21/ HDAC1/ DNMT1/ P53/ BAX axis and apoptosis, via extrinsic pathway activating caspases. These findings indicate that LUCAT1 is maybe a potential therapeutic target and molecular biomarker for PTC.

Up-regulation of ZFAS1 indicates dismal prognosis for cholangiocarcinoma and promotes proliferation and metastasis by modulating USF1 via miR-296-5p

LncRNAs has been demonstrated to modulate neoplastic development by modulating downstream miRNAs and functional genes. In this study, we aimed to detect the interaction among lncRNA ZFAS1 miR‐296‐5p and USF1. We explored the proliferation, migration and invasion of cholangiocarcinoma. The differentially expressed ZFAS1 was discovered in both tissues and cell lines by qRT‐PCR. The targeting relationship between miR‐296‐5p and ZFAS1 or USF1 was validated by dual‐luciferase assay. The impact of ZFAS1 on CCA cell proliferation was observed by CCK‐8 assay. The protein expression of USF1 was determined by Western blot. The effects of ZFAS1, miR‐296‐5p and USF1 on tumour growth were further confirmed using xenograft model. LncRNA ZFAS1 expression was relatively up‐regulated in tumour tissues and cells while miR‐296‐5p was significantly down‐regulated. Knockdown of ZFAS1 significantly suppressed tumour proliferation, migration, invasion and USF1 expression. Overexpressed miR‐296‐5p suppressed cell proliferation and metastasis. Knockdown of USF1 inhibited cell proliferation and metastasis and xenograft tumour growth. In conclusion, ZFAS1 might promote cholangiocarcinoma proliferation and metastasis by modulating USF1 via miR‐296‐5p.

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 non-coding RNAs are emerging targets of phytochemicals for cancer and other chronic diseases

The long non-coding RNAs (lncRNAs) are the crucial regulators of human chronic diseases. Therefore, approaches such as antisense oligonucleotides, RNAi technology, and small molecule inhibitors have been used for the therapeutic targeting of lncRNAs. During the last decade, phytochemicals and nutraceuticals have been explored for their potential against lncRNAs. The common lncRNAs known to be modulated by phytochemicals include ROR, PVT1, HOTAIR, MALAT1, H19, MEG3, PCAT29, PANDAR, NEAT1, and GAS5. The phytochemicals such as curcumin, resveratrol, sulforaphane, berberine, EGCG, and gambogic acid have been examined against lncRNAs. In some cases, formulation of phytochemicals has also been used. The disease models where phytochemicals have been demonstrated to modulate lncRNAs expression include cancer, rheumatoid arthritis, osteoarthritis, and nonalcoholic fatty liver disease. The regulation of lncRNAs by phytochemicals can affect multi-steps of tumor development. When administered in combination with the conventional drugs, phytochemicals can also produce synergistic effects on lncRNAs leading to the sensitization of cancer cells. Phytochemicals target lncRNAs either directly or indirectly by affecting a wide variety of upstream molecules. However, the potential of phytochemicals against lncRNAs has been demonstrated mostly by preclinical studies in cancer models. How the modulation of lncRNAs by phytochemicals produce therapeutic effects on cancer and other chronic diseases is discussed in this review.

Diagnostic and prognostic biomarkers in cholangiocarcinoma

The high mortality rate of cholangiocarcinoma (CCA) is due, in part, to the lack of non-invasive approaches able to accurately detect this silent tumour at early stages, when therapeutic options can be potentially curative or may at least increase the overall survival of patients. The fact that the majority of CCA tumours are not linked to any known aetiological factor highly compromises the monitoring of patients at risk for tumour development and also their early diagnosis. Combination of clinical/biochemical features, imaging techniques and analysis of non-specific tumour biomarkers in serum are commonly used to help in the diagnosis of CCA, but tumour biopsy is usually required to confirm the diagnosis. Moreover, no prognostic biomarkers are currently used in the clinical setting, deserving more innovative research, and international validation and consensus. Important efforts have been made in the last few years to identify accurate non-invasive biomarkers, by using innovative techniques and high-throughput omics technologies. This review summarizes and discusses the advances in the investigation of novel diagnostic and prognostic biomarkers in CCA and envisions the future directions in this field of research.

Long non-coding RNA LOXL1-AS1 acts as a ceRNA for miR-324-3p to contribute to cholangiocarcinoma progression via modulation of ATP-binding cassette transporter A1

Accumulating evidence has appreciated long non-coding RNAs (lncRNAs) as novel prognostic markers and therapeutic targets in malignant carcinomas. Here, we aim to investigate the value of a novel cancer-related lncRNA, LOXL1-AS1, in cholangiocarcinoma (CCA). LOXL1-AS1 was found overexpressed in CCA tissues screened by high-throughput sequencing technology. Upregulation of LOXL1-AS1 was identified by TCGA database and qRT-PCR analysis. Additionally, upregulation of LOXL1-AS1 was associated with lymph node invasion, advanced TNM stages and unfavorable prognosis. Loss-of-function and gain-of-function experiments were conducted and validated that LOXL1-AS1 could facilitate cell proliferation, migration and invasion and attenuate cell apoptosis. Moreover, luciferase reporter and rescue assays indicated that LOXL1-AS1 functioned as a ceRNA to elevate ATP-binding cassette transporter A1 (ABCA1) level by sponging miR-324-3p and exhibited the malignant phenotypes of CCA cells, thereby playing an oncogenic role in CCA. Taken together, this study reveals that LOXL1-AS1 might act as a potential biomarker and therapeutic target for CCA clinical application.

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.

E2F1-induced upregulation of long non-coding RNA LMCD1-AS1 facilitates cholangiocarcinoma cell progression by regulating miR-345-5p/COL6A3 pathway

Cholangiocarcinomas (CCA) is a refractory cancer with increasing incidence worldwide. Long non-coding RNAs (lncRNAs) have been shown to associate with the occurrence and development of CCA. A previous study identified upregulation of LMCD1-AS1 in CCA tissues relative to their normal counterparts by Agilent human lncRNA + mRNA arrayV4.0. However, the biological roles and molecular mechanisms of LMCD1-AS1-regulated tumorigenesis and progression of CCA remain to be elucidated. In our study, we confirmed that LMCD1-AS1 expression was significantly higher in CCA tissues and cell lines than in normal tissues and HIBEC, respectively. E2F1 could bind directly to the promoter region of LMCD1-AS1 and activate its transcription. Function study showed depletion of LMCD1-AS1 suppressed cell proliferation, clone formation and invasion, and induced apoptosis of CCA cells. Whereas, ectopic expressed LMCD1-AS1 facilitated CCA cell progression. In addition, LMCD1-AS1 could sponge miR-345-5p in CCA cells. Moreover, collagenVI-alpha3 chain (COL6A3) was found as a downstream target of miR-345-5p by bioinformatic prediction and dual luciferase reporter assay. Furthermore, we demonstrated that the oncogenic role of LMCD1-AS1 is partly dependent on COL6A3 expression. Taken together, we reported a newly identified regulatory mechanism of E2F1/LMCD1-AS1/miR-345-5p/COL6A3 axis, which might lead to a better understanding of CCA tumorigenesis and progression and provide potential therapeutic targets for 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.

The Interaction Between lncRNA SNHG1 and miR-140 in Regulating Growth and Tumorigenesis via the TLR4/NF-κB Pathway in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary hepatobiliary carcinoma. The long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) has been reported to contribute to the progression of multiple cancers. Nonetheless, the functions and hidden mechanism of SNHG1 remain unclear in CCA. In this study, the SNHG1 levels were boosted in CCA cell lines, and knockdown of SNHG1 repressed CCA cell proliferation and invasion in vitro. The data also demonstrated that miR-140 could act as a target of SNHG1 in CCA and inhibited CCA cell proliferation and invasion, whereas the inhibition effects were relieved by overexpression of SNHG1. In addition, Toll-like receptor 4 (TLR4), an NF-κB-activating signal, was identified to be a target of miR-140. SNHG1, as a competing endogenous RNA (ceRNA) for miR-140, enhanced TLR4 expression and activated NF-κB signaling, thereby regulating growth and tumorigenesis in CCA. Animal experiments further confirmed this conclusion. Collectively, these findings not only uncovered a key role of SNHG1/miR-140/TLR4/NF-κB signaling axis in CCA tumorigenesis and progression but also denoted the probable utilization of SNHG1 as a therapeutic target for CCA.

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.

SP1-induced upregulation of lncRNA PANDAR predicts adverse phenotypes in retinoblastoma and regulates cell growth and apoptosis in vitro and in vivo

Retinoblastoma (RB) is an intraocular malignancy for children and has a high mortality rate. Long non-coding RNAs (lncRNAs) are emerging as gene regulators and biomarkers in various malignancies. PANDAR is a novel cancer-related lncRNA that dysregulated in several types of cancers. However, its clinical value and potential effects on RB remains unclear. RT-qPCR was used to assess the relative expression of PANDAR in RB tissues and cells. Additionally, chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to investigate whether SP1 could bind to the promoter region of PANDAR and activate its transcription. Furthermore, in vitro and in vivo studies were induced to elucidate the biological functions of PANDAR. The results indicated that PANDAR was increased in RB tissues and cells, and this upregulation was associated with advanced IIRC stage, positive optic nerve invasion, and lower differentiation grade in RB patients. In addition, SP1 could bind directly to the PANDAR promoter region and activate its transcription. Furthermore, PANDAR silencing yielded tumor suppressive effects both in vitro and in vivo. Importantly, PANDAR protects against apoptosis partly by affecting Bcl-2/caspase-3 pathway. Ultimately, our work first illustrate that PANDAR plays an oncogenic role in RB and may offer a potential therapeutic target for treating this devastating disease.

Long non-coding RNA HOTAIR promotes tumorigenesis and forecasts a poor prognosis in cholangiocarcinoma

Cholangiocarcinoma (CCA) arising from the neoplastic transformation of cholangiocytes with increasing incidence in the worldwide. Unfortunately, a large amount of CCA patients lost their chance for surgery because it is hard to diagnose in the early stages. Long non-coding RNAs (lncRNAs) is closely associated with development and progression of various malignant tumors. Hox transcript antisense intergenic (HOTAIR), a negative prognostic factor for patients with gastric, liver and pancreatic carcinoma. Its transcription levels and functional roles in CCA is still unknown. Therefore, we aimed to explore the effect of HOTAIR in CCA including cell proliferation, apoptosis, migration, invasion and epithelial-to-mesenchymal transition (EMT). The results showed that HOTAIR was highly expressed both in CCA tissue samples and cell lines compared with corresponding normal bile duct tissues and Human intrahepatic biliary epithelial cells (HIBEC). Its overexpression was closely correlated with Tumor size, TNM stage and postoperative recurrence in CCA patients. Moreover, up-regulation of HOTAIR has correlation with prognosis in CCA patients. Knockdown of HOTAIR by siRNAs significantly decreased the migration and invasion but increased apoptosis of CCA cells in vitro. Overall, our study revealed that HOTAIR may play as a new potential therapeutic target and forecast poor prognosis for this fatal disease.

Non-Coding RNAs and Resistance to Anticancer Drugs in Gastrointestinal Tumors

Non-coding RNAs are important regulators of gene expression and transcription. It is well established that impaired non-coding RNA expression especially the one of long non-coding RNAs and microRNAs is involved in a number of pathological conditions including cancer. Non-coding RNAs are responsible for the development of resistance to anticancer treatments as they regulate drug resistance-related genes, affect intracellular drug concentrations, induce alternative signaling pathways, alter drug efficiency via blocking cell cycle regulation, and DNA damage response. Furthermore, they can prevent therapeutic-induced cell death and promote epithelial-mesenchymal transition (EMT) and elicit non-cell autonomous mechanisms of resistance. In this review, we summarize the role of non-coding RNAs for different mechanisms resulting in drug resistance (e.g., drug transport, drug metabolism, cell cycle regulation, regulation of apoptotic pathways, cancer stem cells, and EMT) in the context of gastrointestinal cancers.

Long non-coding RNA PANDAR promotes melanoma cell invasion through regulating epithelial-mesenchymal transition

Melanoma is a malignant skin tumor and has a poor cure rate because of its high metastatic potential. Overexpression of long non-coding (lnc) RNA PANDAR has been observed in several kinds of cancer, but the function of PANDAR on melanoma is still unclear. Therefore, this study was to explore the mechanism of PANDAR on the occurrence and progression in malignant melanoma. We detected expression of PANDAR in malignant melanoma tissues and cell lines by qRT-PCR and analyzed correlation of PANDAR expression with the patients' prognosis. Furthermore, we investigated the effects of PANDAR on cell viability, migration, invasion, tumorigenesis, and epithelial-mesenchymal transition (EMT) using CCK-8, Transwell, and nude mouse subcutaneous tumor formation model assays and Western blotting analysis, respectively. From the results, we discovered that the PANDAR expression is strikingly upregulated in melanoma tissues compared with paired-adjacent non-tumorous tissues and elevated PANDAR is positively correlated with short overall survival time. The results also demonstrate that knockdown of PANDAR inhibits cell viability, migration, invasion, tumorigenesis, and EMT, whereas overexpression of PANDAR gave opposite results by promoting cell viability, migration, invasion, tumorigenesis, and EMT of melanoma cells. These new findings all illustrate that PANDAR might play a pivotal oncogenic role in the occurrence and development of melanoma, and PANDAR might promote melanoma cell invasion through regulating EMT, providing a potential diagnostic and therapeutic target for melanoma.

Prognostic biomarkers for cholangiocarcinoma and their clinical implications

INTRODUCTION

Cholangiocarcinoma (CCA) is a poorly prognostic cancer with limited treatment options. Most patients have unresectable tumors when they are diagnosed and the chemotherapies provided are of limited benefit. Prognostic markers are therefore necessary to predict the disease outcome, risk of relapse, or to suggest the best treatment option. Areas covered: This article provides an up-to-date review of biomarkers with promising characteristics to be prognostic markers for CCA reported in the past 5 years. The biomarkers are sub-classified into tissue and serum markers. Proteins, RNAs, peripheral blood cells etc., that are associated with aggressive phenotypes, signal pathways, chemo-drug resistance, and those that reflect the survival time of CCA patients are evaluated for their prognostic prediction values. Expert commentary: CCAs are heterogeneous tumors of different histo-pathological subtypes and genetic influences and, therefore, potential markers should be validated in larger collectives with varied epidemiological backgrounds. A systematic review and meta-analysis should be done to clarify the impact of the reported biomolecules for their potential prognostic values. Non- or low-invasive sample collections, as well as the simple and affordable determination methods, should be constructed to make the prognostic biomarkers available in clinical practice.

Long noncoding RNA PANDAR blocks CDKN1A gene transcription by competitive interaction with p53 protein in gastric cancer

Emerging evidence indicates that lncRNAs play important roles in cancer tumourigenesis and could be used as potential diagnostic biomarkers or therapeutic targets. However, the clinical significance and molecular mechanism of lncRNAs in gastric cancer (GC) is still unclear. The aim of this study was to explore the expression and role of lncRNAs in GC. The relative expression level of lncRNAs in GC samples was examined by an lncRNA microarray analysis, northern blot analysis and qRT-PCR analysis. A Kaplan−Meier survival analysis and univariate and multivariate Cox proportional hazards models were performed to evaluate the clinical and prognostic significance of PANDAR (promoter of CDKN1A antisense DNA damage activated RNA) in GC patients. The binding activity of PANDAR with the p53 protein was analysed by an RNA immunoprecipitation analysis and RNA pull-down analysis. The depletion of PANDAR was conducted using the CRISPR/Cas9 system for PANDAR. The biological functions of PANDAR in GC cells were determined both in vitro and in vivo. Upregulated PANDAR in GC patients was positively correlated with increased tumour size, advanced TNM classification and a poor survival rate in GC patients. The ROC curves identified that the PANDAR level was a marker for discriminating the early-stage tumour group from the healthy group, the metastasis group from the non-metastasis group and the chemoresistance group from the chemosensitive group in GC patients. As a target, the CDKN1A gene was successfully downregulated by PANDAR. PANDAR controlled the transcription of the CDKN1A gene by competitively binding with p53 protein. In combination with a p53 activator (nutlin3), the knockout of PANDAR by CRISPR/Cas9 technology synergistically inhibited GC tumour growth in vivo. Our results suggest that the PANDAR is a powerful diagnostic and therapeutic marker for patients with GC and, combined with other chemotherapeutics, may have distinct antitumour effects.

Long non-coding PANDAR as a novel biomarker in human cancer: A systematic review

OBJECTIVES

Long non-coding RNAs (lncRNAs) are characterized as a group of RNAs that more than 200 nucleotides in length and have no protein-coding function. More and more evidences provided that lncRNAs serve as key molecules in the development of cancer. Deregulation of lncRNAs functions as either oncogenes or tumour suppressor genes in various diseases. Recently, increasing studies about PANDAR in cancer progression were reported. In our review, we will focus on the current research on the character of PANDAR include the clinical management, tumour progression and molecular mechanisms in human cancers.

MATERIALS AND METHODS

We summarize and analyze current studies concerning the biological functions and mechanisms of lncRNA PANDA in tumour development. The related studies were obtained through a systematic search of Pubmed.

RESULTS

PANDAR was a well-characterized oncogenic lncRNA and widely overexpressed in many tumours. PANDAR is upregulated in many types of cancer, including colorectal cancer, lung cancer, renal cell carcinoma, cholangiocarcinoma, osteosarcoma, thyroid cancer and other cancers. Upregulation of PANDAR was significantly associated with advanced tumour weights, TNM stage and overall survival. Furthermore, repressed of PANDAR would restrain proliferation, migration and invasion.

CONCLUSION

PANDAR may act as a powerful tumour biomarker for cancer diagnosis and treatment.

NcRNAs and Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most common primary biliary malignancy with poor prognosis. Less understanding of its etiology and pathogenesis makes the diagnosis and therapy difficult. Recently, accumulating evidences have demonstrated that deregulated expression of non-coding RNAs (ncRNAs) is closely associated with the etiopathogenesis of CCA. NcRNAs which lack open reading frame are a heterogeneous class of transcribed RNA molecules, including microRNAs, long non-coding RNAs and circular RNAs. Several studies have shown ncRNAs dysregulation is a common central event occurring in CCA and has the potential of being therapy targets. Moreover, ncRNAs can be easily detected in cancer tissues and biofluids, representing valuable tools for diagnosis. In this review, we illustrate the role of ncRNA in the CCA and discuss their potential clinical value.

Overexpressed long noncoding RNA Sox2ot predicts poor prognosis for cholangiocarcinoma and promotes cell proliferation and invasion

SOX2 overlapping transcript (Sox2ot), a long noncoding RNA (lncRNA), was initially found a close concomitant expression pattern of SOX2 gene. Multiple studies have demonstrated that the relatively upregulated Sox2ot could be observed in different types of cancer tissues and effectively promotes cell proliferation, invasion, and tumorigenesis in vitro. In the present study, we aimed to detect the crucial prognostic role of Sox2ot in cholangiocarcinoma (CCA) patients' clinicopathologic features and evaluated the correlation between Sox2ot expression and CCA patients overall survival. 58 CCA patients who underwent surgical treatment were recruited for the investigation. Sox2ot expression levels estimated by the quantitative real-time PCR (qRT-PCR) showed that both clinical tissues and cell lines possessed the overexpressed states and the upregulation of Sox2ot significantly associated with lymph node invasion (p=0.0308), TNM stage (p=0.0072) and postoperative recurrence (p=0.0019). The Kaplan-Meier curve showed a strong association between Sox2ot and overall survival (OS) and multivariate analysis confirmed this finding. Furthermore, the proliferation, migration and invasion assays were carried out with RBE and QBC939 cell lines and the knockdown of Sox2ot in all experiments could remarkably decrease malignant biological behaviors. Taken together, lncRNA Sox2ot indicates an unfavorable prognostic biomarker and potential therapeutics target for CCA patients.

An increased expression of long non-coding RNA PANDAR promotes cell proliferation and inhibits cell apoptosis in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies worldwide. Emerging evidence indicates that aberrantly expressed long non-coding RNAs (lncRNAs) act as imperative roles in tumorigenesis and progression. PANDAR (promoter of CDKN1A antisense DNA damage activated RNA) is a novel lncRNA that contributes to the development of various cancers. However, its clinical significance and potential effects on PDAC remains unknown. In the present study, qRT-PCR was performed to explore the expression levels of PANDAR in PDAC tissues and corresponding non-tumor tissues, the correlation between PANDAR expression and clinicopathological characteristics was also analyzed. The functional roles of lncRNA PANDAR in PDAC cells were evaluated both in vitro and in vivo. The results indicated that PANDAR was aberrantly overexpressed in PDAC tissues and cell lines, and this overexpression was closely associated with tumor stage and vascular invasion in PDAC patients. Besides, silencing of PANDAR exerted tumor suppressive effect via reducing cell proliferation, colony-forming ability, inducing cell cycle G0/G1 arrest and apoptosis in PANC1 and Capan-2 cells. Further in vivo study confirmed the oncogenesis role of PANDAR in PDAC cells. Overall, our findings may help to develop a potential therapeutic target for the patients with PDAC.