LncRNA HULC triggers autophagy via stabilizing Sirt1 and attenuates the chemosensitivity of HCC cells. Oncogene. 2017;36:3528-3540. [PMID: 28166203 DOI: 10.1038/onc.2016.521]

METase/lncRNA HULC/FoxM1 reduced cisplatin resistance in gastric cancer by suppressing autophagy

BACKGROUND

Autophagy plays an important role in regulating cisplatin (CDDP) resistance in gastric cancer cells. However, the underlying mechanism of methioninase (METase) in the regulation of autophagy and CDDP resistance of gastric cancer cells is still not clear.

MATERIALS AND METHODS

Western blot was used to detect the levels of autophagy-related proteins, multidrug-resistant 1 (MDR-1), and FoxM1 protein. LncRNA HULC was detected by qRT-PCR. Cell viability was detected using CCK-8 assay. The interaction between lncRNA HULC and FoxM1 was confirmed by RNA pull-down and RIP assay.

RESULTS

Lentiviral vector carrying METase (LV-METase) suppressed autophagy and CDDP resistance of drug-resistant gastric cancer cells. LncRNA HULC was significantly downregulated in drug-resistant gastric cancer cells transfected with LV-METase. Besides, we found that lncRNA HULC interacted with FoxM1. In addition, METase suppressed autophagy to reduce CDDP resistance of drug-resistant gastric cancer cells through regulating HULC/FoxM1, and interfering HULC suppressed autophagy to reduce CDDP resistance of drug-resistant gastric cancer cells through regulating FoxM1. Finally, interfering HULC inhibited tumor growth in vivo.

CONCLUSION

METase suppressed autophagy to reduce CDDP resistance of drug-resistant gastric cancer cells through regulating HULC/FoxM1 pathway.

Long noncoding RNA NEAT1 suppresses sorafenib sensitivity of hepatocellular carcinoma cells via regulating miR-335-c-Met

OBJECTIVES

To investigate the role of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating sorafenib (Sora) sensitivity of hepatocellular carcinoma (HCC) cells and possible signaling pathways.

METHODS

HCC cell lines and tumor tissue were quantified for NEAT1 expression by quantitative polymerase chain reaction (qPCR). Following shRNA (short hairpin RNA) knockdown of NEAT1, cell viability, apoptosis, and related protein expression were measured after drug treatment. The downstream target of NEAT1, including miR-335 and c-Met was studied using a combination of luciferase binding assay, gene knockdown/overexpression, western blot analysis, and cell viability/apoptosis assay. Cancer cells with NEAT1 knockdown were transplanted onto nude mice for in vivo tumorigenesis assay.

RESULTS

Silencing of NEAT1 in HCC cells facilitated Sora sensitivity by enhancing drug-induced apoptosis, and led to smaller tumor size on nude mice. Mechanistic study suggested that miR-335 was negatively regulated by NEAT1, and miR-335 further suppressed c-Met-Akt pathway, whose activation caused drug resistance of HCC cells. The knockdown of miR-335, or overexpression of c-Met, all remarkably abolished the proapoptotic effect of NEAT1 knockdown in HCC cells.

CONCLUSION

lncRNA NEAT1 mediates Sora resistance of HCC cells by suppressing miR-335 expression, and disinhibition on c-Met-Akt signaling pathway. Our results provide potency of NEAT1 as the biomarker for drug resistant HCC and possible treating targets.

LncRNA HULC promotes lung squamous cell carcinoma by regulating PTPRO via NF-κB

Accumulating studies have implicated that long noncoding RNA (lncRNA) plays a vital role in lung cancer. However, little is known of the role of lncRNA highly upregulated in liver cancer (HULC) in the pathogenesis of lung squamous cell carcinoma (LSCC). In this study, we investigated the modifying effects and underlying mechanisms of lncRNA HULC in LSCC. Significantly decreased level of lncRNA HULC was observed in LSCC samples compared with adjacent tissues. Besides, the expression of lncRNA HULC was negatively associated with protein tyrosine phosphatase receptor type O (PTPRO) in LSCC. Moreover, lncRNA HULC could promote the proliferation of LSCC cells by downregulating the expression PTPRO dependent on the phosphorylation and activation of nuclear factor-κB (NF-κB). The present study firstly shows strong evidence supporting a critical role of lncRNA HULC in promoting LSCC by regulating PTPRO/NF-κB signaling pathway, which provides new promising biomarkers for LSCC.

The long noncoding RNA KCNQ1DN suppresses the survival of renal cell carcinoma cells through downregulating c-Myc

Background: Long noncoding RNAs (lncRNAs) have been demonstrated to play essential roles in renal cell carcinoma (RCC). However, the role of lncRNA KCNQ1DN in RCC remains unclear.

Methods: The expression of KCNQ1DN in RCC and the corresponding adjacent tissues was measured by qPCR. RNA fluorescence in situ hybridization (FISH) assay, methylation analysis, reporter gene assays and functional tests were performed to reveal the effects of KCNQ1DN on RCC.

Results: In the present study, we found that lncRNA KCNQ1DN was notably decreased in RCC tissues and cell lines. RNA FISH assay showed that KCNQ1DN mainly localized to the cytoplasm. Methylation analysis revealed that the proximal region of KCNQ1DN promoter was hypermethylated in RCC tissues relative to the adjacent normal ones. Functional studies clarified that KCNQ1DN repressed the RCC cell growth and cell cycle progression. Mechanistically, KCNQ1DN inhibited the expression of c-Myc, which might further upregulate cyclin D1 and suppress p27 at mRNA and protein levels in RCC cells. Reporter gene assays revealed that the transcriptional activity of c-Myc promoter was inhibited by KCNQ1DN. The in vivo experiments in nude mice showed that KCNQ1DN overexpression dramatically repressed the growth of xenograft tumors and the expression of corresponding c-Myc.

Conclusion: These results indicated that KCNQ1DN inhibit the growth of RCC cells in vitro and in vivo through repressing the oncogene c-myc, suggesting that KCNQ1DN may serve as a novel target for the treatment of RCC.

Long non-coding RNA TUG1 mediates 5-fluorouracil resistance by acting as a ceRNA of miR-197-3p in colorectal cancer

One major reason for the failure of advanced colorectal cancer (CRC) treatment is the occurrence of chemoresistance to fluoropyrimidine (Fu)-based chemotherapy. Accumulating evidence indicates that long non-coding RNAs (lncRNAs) play a critical role in cancerous processes as either oncogenes or tumor suppressor genes. Here, we observed lncRNA TUG1 was associated to the 5-Fu resistance in colorectal cancer. Firstly, quantitative analysis indicated that TUG1 was significantly increased in recurrence CRC patient samples. Kaplan-Meier survival analysis indicated that high TUG1 expression in CRC tissues was significantly associated with a higher rate of disease progression. TUG1 knockdown re-sensitized the 5-Fu resistance in colorectal cancer cells, which were 5-Fu-resistant colorectal cell line. Furthermore, bioinformatics analysis showed that miR-197-3p could directly bind to TUG1 suggesting TUG1 might work as a ceRNA to sponge miR-197-3p. Extensively, our study also showed that TYMS was the direct target of miR-197-3p in CRC cells. Taken together, our study suggests that TUG1 mediates 5-Fu resistance in CRC via miR-197-3p/TYMS axis.

HNRNPA2/B1 is upregulated in endocrine-resistant LCC9 breast cancer cells and alters the miRNA transcriptome when overexpressed in MCF-7 cells

MicroRNAs are dysregulated in breast cancer. Heterogeneous Nuclear Ribonucleoprotein A2/B1 (HNRNPA2/B1) is a reader of the N(6)-methyladenosine (m6A) mark in primary-miRNAs (pri-miRNAs) and promotes DROSHA processing to precursor-miRNAs (pre-miRNAs). We examined the expression of writers, readers, and erasers of m6A and report that HNRNPA2/B1 expression is higher in tamoxifen-resistant LCC9 breast cancer cells as compared to parental, tamoxifen-sensitive MCF-7 cells. To examine how increased expression of HNRNPA2/B1 affects miRNA expression, HNRNPA2/B1 was transiently overexpressed (~5.4-fold) in MCF-7 cells for whole genome miRNA profiling (miRNA-seq). 148 and 88 miRNAs were up- and down-regulated, respectively, 48 h after transfection and 177 and 172 up- and down-regulated, respectively, 72 h after transfection. MetaCore Enrichment analysis identified progesterone receptor action and transforming growth factor β (TGFβ) signaling via miRNA in breast cancer as pathways downstream of the upregulated miRNAs and TGFβ signaling via SMADs and Notch signaling as pathways of the downregulated miRNAs. GO biological processes for mRNA targets of HNRNPA2/B1-regulated miRNAs included response to estradiol and cell-substrate adhesion. qPCR confirmed HNRNPA2B1 downregulation of miR-29a-3p, miR-29b-3p, and miR-222 and upregulation of miR-1266-5p, miR-1268a, miR-671-3p. Transient overexpression of HNRNPA2/B1 reduced MCF-7 sensitivity to 4-hydroxytamoxifen and fulvestrant, suggesting a role for HNRNPA2/B1 in endocrine-resistance.

Transcriptome Analyses Reveal Effects of Vitamin C-Treated Donor Cells on Cloned Bovine Embryo Development

Somatic cell nuclear transfer (SCNT) is a very powerful technique used to produce genetically identical or modified animals. However, the cloning efficiency in mammals remains low. In this study, we aimed to explore the effects of vitamin C (Vc)-treated donor cells on cloned embryos. As a result, Vc treatment relaxed the chromatin of donor cells and improved cloned embryo development. RNA sequencing was adopted to investigate the changes in the transcriptional profiles in early embryos. We found that Vc treatment increased the expression of genes involved in the cell–substrate adherens junction. Gene ontology (GO) analysis revealed that Vc treatment facilitated the activation of autophagy, which was deficient in cloned two-cell embryos. Rapamycin, an effective autophagy activator, increased the formation of cloned blastocysts (36.0% vs. 25.6%, p < 0.05). Abnormal expression of some coding genes and long non-coding RNAs in cloned embryos was restored by Vc treatment, including the zinc-finger protein 641 (ZNF641). ZNF641 compensation by means of mRNA microinjection improved the developmental potential of cloned embryos. Moreover, Vc treatment rescued some deficient RNA-editing sites in cloned two-cell embryos. Collectively, Vc-treated donor cells improved the development of the cloned embryo by affecting embryonic transcription. This study provided useful resources for future work to promote the reprogramming process in SCNT embryos.

LncRNA-Regulated Autophagy and its Potential Role in Drug-Induced Liver Injury

INTRODUCTION AND AIM

Autophagy and its regulated pathways participate in many important cellular physiology and pathological processes involving protein aggregates, damaged mitochondria, excessive peroxisomes, ribosomes, and invading pathogens. This study aimed to review recently published studies and further describe the long noncoding RNA (lncRNA)-regulated autophagy during drug-induced liver injury (DILI).

MATERIAL AND METHODS

DILI, autophagy, autophagy-related genes (ATGs), and lncRNA were used as key words to search published studies from PubMed, Google Scholar, and Web of Science. All related studies were reviewed and analyzed.

RESULTS

Many studies explicitly indicated that DILI and its progression to acute liver failure were causatively linked to endoplasmic reticulum stress and subsequently induced autophagy, which protect hepatocytes during DILI. LncRNA, as a noncoding RNA, influences the regulation of the expression of ATGs to manipulate autophagy.

CONCLUSIONS

This review described the recent findings on autophagy and its possible lncRNA-miRNA-associated pathways, thereby providing new insights for further studies on the pathogenesis of DILI.

LncRNA SNHG1 contributes to sorafenib resistance by activating the Akt pathway and is positively regulated by miR-21 in hepatocellular carcinoma cells

Background

Acquired resistance to sorafenib greatly limits its therapeutic efficiency in the treatment of hepatocellular carcinoma (HCC). Increasing evidence indicates that long noncoding RNAs (lncRNAs) play important roles in the resistance to anti-cancer drugs. The present study aims to explore the involvement of lncRNA SNHG1 (small nucleolar RNA host gene 1) in sorafenib resistance and how SNHG1 is associated with overexpressed microRNA-21 (miR-21) and the activated Akt pathway, which have been demonstrated to mediate this resistance in HCC cells.

Methods

Sorafenib-resistant HCC (SR-HCC) cells were generated and their sorafenib-resistant properties were confirmed by cell viability and apoptosis assays. Potential lncRNAs were screened by using multiple bioinformatics analyses and databases. The expression of genes and proteins was detected by qRT-PCR, Western blot and in situ hybridization. Gene silencing was achieved by specific siRNA or lncRNA Smart Silencer. The effects of anti-SNHG1 were evaluated in vitro and in experimental animals by using quantitative measures of cell proliferation, apoptosis and autophagy. The binding sites of miR-21 and SNHG1 were predicted by using the RNAhybrid algorithm and their interaction was verified by luciferase assays.

Results

The Akt pathway was highly activated by overexpressed miR-21 in SR-HCC cells compared with parental HCC cells. Among ten screened candidates, SNHG1 showed the largest folds of alteration between SR-HCC and parental cells and between vehicle- and sorafenib-treated cells. Overexpressed SNHG1 contributes to sorafenib resistance by activating the Akt pathway via regulating SLC3A2. Depletion of SNHG1 enhanced the efficacy of sorafenib to induce apoptosis and autophagy of SR-HCC cells by inhibiting the activation of Akt pathway. Sorafenib induced translocation of miR-21 to the nucleus, where it promoted the expression of SNHG1, resulting in upregulation of SLC3A2, leading to the activation of Akt pathway. In contrast, SNHG1 was shown to have little effect on the expression of miR-21, which downregulated the expression of PTEN, leading to the activation of the Akt pathway independently of SNHG1.

Conclusions

The present study has demonstrated that lncRNA SNHG1 contributes to sorafenib resistance by activating the Akt pathway and its nuclear expression is promoted by miR-21, whose nuclear translocation is induced by sorafenib. These results indicate that SNHG1 may represent a potentially valuable target for overcoming sorafenib resistance for HCC.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1177-0) contains supplementary material, which is available to authorized users.

Long non-coding RNA HULC activates HBV by modulating HBx/STAT3/miR-539/APOBEC3B signaling in HBV-related hepatocellular carcinoma

Long noncoding RNA HULC is identified and highly expressed in hepatocellular carcinoma (HCC). Hepatitis B virus (HBV) is a key driver of liver cancer. In the present study, we found that HULC remarkably elevated the levels of HBeAg, HBsAg, HBcAg, pgRNA, HBx, HBV DNA and covalently closed circular DNA (cccDNA), which activated the HBV replication in HBV-expressing hepatoma cells or de novo HBV-infected cell lines (PHH, HepG2-NTCP and dHepaRG). Mechanistically, HULC enhanced HBV cccDNA stability by down-regulating the APOBEC3B in hepatoma cells. HULC significantly up-regulated microRNA-539, which targeted the 3'UTR of APOBEC3B mRNA. Luciferase reporter gene assays revealed a putative STAT3-binding site located in the upstream of miR-539 promoter. Moreover, we identified that HULC was able to elevate HBx, which co-activated the STAT3 to stimulate the miR-539 promoter. Then, miR-539 down-regulated APOBEC3B and promoted HBV replication. Functionally, HULC enhanced the growth of hepatoma cells by activating HBV in vitro and in vivo, which could be blocked by overexpressing APOBEC3B. In conclusion, HULC activates HBV by modulating HBx/STAT3/miR-539/APOBEC3B signaling in HBV-related HCC.

Long noncoding RNA EPB41L4A-AS2 inhibits hepatocellular carcinoma development by sponging miR-301a-5p and targeting FOXL1

BACKGROUND

Hepatocellular carcinoma (HCC) is the major histological type of liver cancer with high morbidity and mortality worldwide. Long noncoding RNAs (lncRNA) has been proved to be associated with various cancer types, while its regulation in HCC is largely unknown.

METHODS

To figure out the specific role of lncRNA EPB41L4A-AS2 in HCC. Fluorescence in situ hybridization (FISH) was first used to determine the cellular sublocalization of EPB41L4A-AS2 to determine its primary mode of action. QRT-PCR, Western blot and hematoxylin-eosin staining were then used to measure the expression of genes in cells and tissues. Cell proliferation and invasion assays were performed to determine the effects of EPB41L4A-AS2, miR-301a-5p and FOXL1 on the malignant phenotype of tumor cells. With luciferase reporter assay, the direct interaction between target genes were further confirmed for research on molecular mechanism. Finally, the mice hepatocarcinoma model was also established to disclose the tumor suppressor effects of EPB41L4A-AS2 in vivo.

RESULTS

Here, we have identified a novel lncRNA EPB41L4A-AS2, which is significantly downregulated both in HCC cells and tissues, and plays a negative regulatory role in HCC proliferation and invasion. Mechanistically, cytoplasmic lncRNA EPB41L4A-AS2 functions as an efficient miR-301a-5p sponge, thereby release the expression inhibition of forkhead box L1 (FOXL1). Indeed, lncRNA EPB41L4A-AS2 inhibits proliferation and migration by upregulating FOXL1 expression and FOXL1 was confirmed as a direct target of miR-301a-5p. MiR-301a-5p shows an inverse correlation with EPB41L4A-AS2 expression and was verified as a direct target of EPB41L4A-AS2 as well. Correspondingly, FOXL1 and miR-301a-5p show opposite biological effects in cell proliferation and migration. Moreover, miR-301a-5p overexpression rescued the EPB41L4A-AS2 upregulation induced depression in proliferation, migration and invasion of HCC cells, as well as promotion effect on FOXL1 expression. Also, in vivo experiments proved that EPB41L4A-AS2 suppress tumor growth and extrahepatic metastasis (lung) via the miR-301a-5p-FOXL1 axis.

CONCLUSIONS

Taken together, this research revealed a concrete mechanism of lncRNA EPB41L4A-AS2 in HCC, which may serve as a potential biomarkers and novel therapeutic targets for further clinical application.

Inhibition of lncRNA HULC improves hepatic fibrosis and hepatocyte apoptosis by inhibiting the MAPK signaling pathway in rats with nonalcoholic fatty liver disease

This study is conducted to investigate the role of long noncoding RNA highly upregulated in liver cancer (lncRNA HULC) on hepatic fibrosis and hepatocyte apoptosis by inhibiting the mitogen-activated protein kinase (MAPK) signaling pathway in rats with nonalcoholic fatty liver disease (NAFLD). The successfully modeled rats were injected with HULC siRNA or small interfering RNA (siRNA) negative control into the tail vein. The expression of HULC in liver tissues was detected by reverse transcription quantitative polymerase reaction chain. The role of HULC in pathological state and liver function-related indexes of liver lipid deposition, the degree of hepatic fibrosis and hepatocyte apoptosis in rats with NAFLD were also investigated through a series of experiments. Increased expression of HULC was found in liver tissue of NAFLD rats. Inhibition of HULC improved the pathological state and liver function-related indexes of liver lipid deposition, improved the degree of hepatic fibrosis, reduced hepatocyte apoptosis, and inhibited the MAPK signaling pathway in the liver tissue of NAFLD rats. The inhibition of p38 and JNK improved the pathological state of liver lipid deposition and liver function to some extent, improved the degree of hepatic fibrosis, and reduced the apoptosis of hepatocytes in NAFLD rats. Collectively, this present study provides evidence that inhibition of lncRNA HULC improves hepatic fibrosis and decrease hepatocyte apoptosis in rats with NAFLD by inhibiting the MAPK signaling pathway.

Updates on the epigenetic roles of sirtuins

Sirtuins are a class of enzyme with NAD⁺-dependent protein lysine deacylase activities. They were initially discovered to regulate transcription and life span via histone deacetylase activities. Later studies expanded their activities to other proteins and acyl lysine modifications. Through deacylating various substrate proteins, they regulate many biological processes, including transcription, DNA repair and genome stability, metabolism, and signal transduction. Here, we review recent understandings of the epigenetic functions (broadly defined to include transcriptional, post-transcriptional regulation, and DNA repair) of mammalian sirtuins. Because of the important functions of sirtuins, their own regulation is of great interest and is also discussed.

A novel, liver-specific long noncoding RNA LINC01093 suppresses HCC progression by interaction with IGF2BP1 to facilitate decay of GLI1 mRNA

Long noncoding RNAs (lncRNAs) are implicated as novel drivers in hepatocellular carcinoma (HCC), but the underlying mechanisms of this relationship with hepatocarcinogenesis are unknown. We report a novel, liver-specific lncRNA LINC01093 that shows significant downregulation in HCC tissues. LINC01093 expression is inversely correlated with cancer embolus and HCC TNM stage and as a prognostic predictor for HCC patients. LINC01093 overexpression significantly suppresses HCC cell proliferation and metastasis in vitro and in vivo. Conversely, its knockdown promotes HCC progression. Mechanistic analyses indicate that LINC01093 directly binds insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), interfering with interaction between IGF2BP1 and glioma-associated oncogene homolog 1 (GLI1) mRNA. The result is degradation of GLI1 mRNA, further affecting expression of GLI1 downstream molecules involved in HCC progression. The liver-enriched lncRNA LINC01093 is a promising prognostic indicator for HCC patients, and the newly identified LINC01093-IGF2BP1-GLI1 axis shows potential for therapeutic targets in HCC.

Emerging roles of lncRNAs in the post-transcriptional regulation in cancer

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) can play a pivotal role in regulation of diverse cellular processes. In particular, lncRNAs can serve as master gene regulators at transcriptional and posttranscriptional levels, leading to tumorigenesis. In this review, we discuss latest developments in lncRNA-meditated gene expression at the post-transcriptional level, including gene splicing, mRNA stability, protein stability and nuclear trafficking.

The therapeutic role of long non-coding RNAs in human diseases: A focus on the recent insights into autophagy

Long non-coding RNA (lncRNA) is a class of non-coding RNA with ≥200 nucleotides in length which are involved as critical regulators in various cellular processes. LncRNAs contribute to the development and progression of many human diseases. Autophagy is a key catabolic process which helps to maintain the cellular homeostasis through the decay of damaged or unwanted proteins and dysfunctional cytoplasmic organelles. The impairment of the autophagy process has been described in numerous diseases. The autophagy possess can have either a protective or a detrimental role in cells depending on its activation status and other cellular conditions. LncRNAs have been shown to have an important function in the regulation of important biological processes such as autophagy. The relationship between lncRNAs and autophagy has been shown to be involved in the progression and possibly in the prevention of many diseases. In this review, recent findings on the regulatory roles of lncRNAs in the cell autophagy pathway, as well as their relevance to different diseases such as cardiovascular disease, cerebral ischemic stroke and cancer are highlighted.

Increased long noncoding RNA LASP1-AS is critical for hepatocellular carcinoma tumorigenesis via upregulating LASP1

Aberrant long noncoding RNAs (lncRNA) have been proved to be associated with the many types of malignant tumors (including hepatocellular carcinoma [HCC]). In this study, a lncRNAs and mRNAs microarray analysis was performed in three pairs of HCC patitents' tumor. We found lncRNA LIM and SH3 protein 1 antisense (LASP1-AS) and its sense-cognate gene LIM and SH3 protein 1 (LASP1) were upregulated in HCC and both are correlated with poorer prognosis and lower survival of HCC patients. Meanwhile, the expression of LASP1-AS correlated positively with LASP1 expression in HCC tissues. LASP1-AS promoted the proliferation, migration, and invasion abilities of HCC in vitro and vivo by enhancing LASP1 expression. Our study explored lncRNA LASP1-AS as an oncogene in HCC and promoted proliferation and metastasis capabilities of HCC via increasing the expression of its sense-cognate gene LASP1. LncRNA LASP1-AS might be a potential valuable prognostic biomarker and potential therapeutic target of HCC.

Involvement of long non-coding RNA HULC (highly up-regulated in liver cancer) in pathogenesis and implications for therapeutic intervention

INTRODUCTION

HULC (highly upregulated in liver cancer) is a long non-coding RNA (lncRNA) which is, as its name suggests, highly upregulated in hepatocellular carcinoma and in several other cancers. Increased HULC expression levels are strongly associated with clinicopathologic features such as tumor stages and overall survival and is a driver of tumor proliferation, migration, and invasion. Areas covered: This review addresses the discovery of HULC and discusses the consequences of HULC deregulation in cancer, the underlying molecular mechanisms and the potential of HULC as a biomarker and therapeutic target. Expert opinion: HULC is a promising candidate as a therapeutic target in cancer; however, more studies are necessary to further elucidate the underlying molecular mechanism(s), especially in cancer types other than hepatocellular carcinomas. Future studies that focus on an optimized HULC-targeting approach are necessary to clarify the best strategy to target this lncRNA in vivo and in patients.

Autophagy-Modulating Long Non-coding RNAs (LncRNAs) and Their Molecular Events in Cancer

Cancer is a global threat of health. Cancer incidence and death is also increasing continuously because of poor understanding of diseases. Although, traditional treatments (surgery, radiotherapy, and chemotherapy) are effective against primary tumors, death rate is increasing because of metastasis development where traditional treatments have failed. Autophagy is a conserved regulatory process of eliminating proteins and damaged organelles. Numerous research revealed that autophagy has dual sword mechanisms including cancer progressions and suppressions. In most of the cases, it maintains homeostasis of cancer microenvironment by providing nutritional supplement under starvation and hypoxic conditions. Over the past few decades, stunning research evidence disclosed significant roles of long non-coding RNAs (lncRNAs) in the regulation of autophagy. LncRNAs are RNA containing more than 200 nucleotides, which have no protein-coding ability but they are found to be expressed in most of the cancers. It is also proved that, autophagy-modulating lncRNAs have significant impacts on pro-survival or pro-death roles in cancers. In this review, we highlighted the recently identified autophagy-modulating lncRNAs, their signaling transduction in cancer and mechanism in cancer. This review will explore newly emerging knowledge of cancer genetics and it may provide novel targets for cancer therapy.

Diverse Functions of Autophagy in Liver Physiology and Liver Diseases

Autophagy is a catabolic process by which eukaryotic cells eliminate cytosolic materials through vacuole-mediated sequestration and subsequent delivery to lysosomes for degradation, thus maintaining cellular homeostasis and the integrity of organelles. Autophagy has emerged as playing a critical role in the regulation of liver physiology and the balancing of liver metabolism. Conversely, numerous recent studies have indicated that autophagy may disease-dependently participate in the pathogenesis of liver diseases, such as liver hepatitis, steatosis, fibrosis, cirrhosis, and hepatocellular carcinoma. This review summarizes the current knowledge on the functions of autophagy in hepatic metabolism and the contribution of autophagy to the pathophysiology of liver-related diseases. Moreover, the impacts of autophagy modulation on the amelioration of the development and progression of liver diseases are also discussed.

CRlncRNA: a manually curated database of cancer-related long non-coding RNAs with experimental proof of functions on clinicopathological and molecular features

Background

Recent studies demonstrated that long non-coding RNAs (lncRNAs) could be intricately implicated in cancer-related molecular networks, and related to cancer occurrence, development and prognosis. However, clinicopathological and molecular features for these cancer-related lncRNAs, which are very important in bridging lncRNA basic research with clinical research, fail to well settle to integration.

Results

After manually reviewing more than 2500 published literature, we collected the cancer-related lncRNAs with the experimental proof of functions. By integrating from literature and public databases, we constructed CRlncRNA, a database of cancer-related lncRNAs. The current version of CRlncRNA embodied 355 entries of cancer-related lncRNAs, covering 1072 cancer-lncRNA associations regarding to 76 types of cancer, and 1238 interactions with different RNAs and proteins. We further annotated clinicopathological features of these lncRNAs, such as the clinical stages and the cancer hallmarks. We also provided tools for data browsing, searching and download, as well as online BLAST, genome browser and gene network visualization service.

Conclusions

CRlncRNA is a manually curated database for retrieving clinicopathological and molecular features of cancer-related lncRNAs supported by highly reliable evidences. CRlncRNA aims to provide a bridge from lncRNA basic research to clinical research. The lncRNA dataset collected by CRlncRNA can be used as a golden standard dataset for the prospective experimental and in-silico studies of cancer-related lncRNAs. CRlncRNA is freely available for all users at http://crlnc.xtbg.ac.cn.

Salidroside improves the hypoxic tumor microenvironment and reverses the drug resistance of platinum drugs via HIF-1α signaling pathway

BACKGROUND

Hypoxia commonly occurs in solid tumors. The hypoxia in the center of solid tumors considerably decreases the chemosensitivity of tumor cells and induces epithelial-mesenchymal transition (EMT) as well as drug resistance of antitumor drugs.

METHODS

Here, the effects of salidroside (Sal) combined with platinum drugs on human hepatocellular carcinoma were examined in vitro and in vivo. We investigated the antitumor effects of Sal by inhibiting the drug resistance and explained its mechanism in inhibiting tumor growth.

FINDINGS

The results showed that Sal co-administration reverses the drug resistance of platinum drugs and suppressed metastasis induced by the hypoxic tumor microenvironment. Sal promoted the degradation of HIF-1α. In conclusion, Sal significantly increased the sensitivity to platinum drugs and inhibited hypoxia-induced EMT in hepatocellular carcinoma (HCC) through inhibiting HIF-1α signaling pathway.

INTERPRETATION

Therefore, Sal may be an effective platinum drug sensitizer that can improve the chemotherapeutic efficacy in patients with HCC.

Salidroside improves the hypoxic tumor microenvironment and reverses the drug resistance of platinum drugs via HIF-1α signaling pathway

BACKGROUND

Hypoxia commonly occurs in solid tumors. The hypoxia in the center of solid tumors considerably decreases the chemosensitivity of tumor cells and induces epithelial-mesenchymal transition (EMT) as well as drug resistance of antitumor drugs.

METHODS

Here, the effects of salidroside (Sal) combined with platinum drugs on human hepatocellular carcinoma were examined in vitro and in vivo. We investigated the antitumor effects of Sal by inhibiting the drug resistance and explained its mechanism in inhibiting tumor growth.

FINDINGS

The results showed that Sal co-administration reverses the drug resistance of platinum drugs and suppressed metastasis induced by the hypoxic tumor microenvironment. Sal promoted the degradation of HIF-1α. In conclusion, Sal significantly increased the sensitivity to platinum drugs and inhibited hypoxia-induced EMT in hepatocellular carcinoma (HCC) through inhibiting HIF-1α signaling pathway.

INTERPRETATION

Therefore, Sal may be an effective platinum drug sensitizer that can improve the chemotherapeutic efficacy in patients with HCC.

Long Stress Induced Non-Coding Transcripts 5 (LSINCT5) Promotes Hepatocellular Carcinoma Progression Through Interaction with High-Mobility Group AT-hook 2 and MiR-4516

Background

Long non-coding RNAs (lncRNAs) have been implicated in various human cancer types. However, the underlying mechanisms involved in hepatocellular carcinoma (HCC) progression remain poorly understood.

Material/Methods

In this study, lncRNA array was used to identify HCC related lncRNAs. RNA immunoprecipitation (RIP) followed mass spectrometry was used to explore lncRNA binding proteins. Western blot, quantitative PCR, tumor sphere formation, migration and viability assay were performed to evaluate the oncogenic role of lncRNAs.

Results

We identified a novel lncRNA named long stress induced non-coding transcripts 5 (LSINCT5) which facilitates HCC progression. LSINCT5 was significantly upregulated in both HCC specimens and cell lines and correlates with poor survival. In vitro experiments showed that LSINCT5 promoted migration and viability of HepG2 and Huh7 cells. The in vivo xenograft mouse model also confirmed an oncogenic role for LSINCT5. RIP in combination with mass spectrometry identified HMGA2 as the LSINCT5 binding partner. LSINCT5 could bind to HMGA2 and decrease proteasome-mediated HMGA2 degradation leading to EMT activation. LSINCT5 also served as a competing endogenous RNA (ceRNA) for miR-4516, resulting in increased STAT3/BclxL expression and attenuated apoptosis.

Conclusions

Our data have collectively established a lncRNA LSINCT5 mediated process during HCC carcinogenesis and might have provided novel insight into therapeutic targeting.

Long non-coding RNA H19 confers 5-Fu resistance in colorectal cancer by promoting SIRT1-mediated autophagy

Chemotherapy failure is the major cause of recurrence and poor prognosis in colorectal cancer (CRC) patients. The role of the differentially expressed lncRNAs in 5-Fluorouracil chemoresistance has not fully explained. Here, we observed lncRNA H19 was associated with the 5-Fu resistance in CRC. Quantitative analysis indicated that H19 was significantly increased in recurrent CRC patient samples. Kaplan–Meier survival analysis indicated that high H19 expression in CRC tissues was significantly associated with poor recurrent free survival. Our functional studies demonstrated that H19 promoted colorectal cells 5-Fu resistance. Mechanistically, H19 triggered autophagy via SIRT1 to induce cancer chemoresistance. Furthermore, bioinformatics analysis showed that miR-194–5p could directly bind to H19, suggesting H19 might work as a ceRNA to sponge miR-194–5p, which was confirmed by Dual-luciferase reporter assay and Immunoprecipitation assay. Extensively, our study also showed that SIRT1 is the novel direct target of miR-194–5p in CRC cells. Taken together, our study suggests that H19 mediates 5-Fu resistance in CRC via SIRT1 mediated autophagy. Our finding provides a novel mechanistic role of H19 in CRC chemoresistance, suggesting that H19 may function as a marker for prediction of chemotherapeutic response to 5-Fu.

Microarray analysis of lncRNA expression in rabies virus infected human neuroblastoma cells

Rabies, caused by the rabies virus (RABV), is the oldest known zoonotic infectious disease. Although the molecular mechanisms of RABV pathogenesis have been investigated extensively, the interactions between host and RABV are not clearly understood. It is now known that long non-coding RNAs (lncRNAs) participate in various physiological and pathological processes, but their possible roles in the host response to RABV infection remain to be elucidated. To better understand the pathogenesis of RABV, RNAs from RABV-infected and uninfected human neuroblastoma cells (SK-N-SH) were analyzed using human lncRNA microarrays. We identified 896 lncRNAs and 579 mRNAs that were differentially expressed after infection, indicating a potential role for lncRNAs in the immune response to RABV. Differentially expressed RNAs were examined using Gene Ontology (GO) analysis and were tentatively assigned to biological pathways using the Kyoto Encyclopedia of Genes and Genomes (KEGG). A lncRNA-mRNA-transcription factor co-expression network was constructed to relate lncRNAs to regulatory factors and pathways that may be important in virus-host interactions. The network analysis suggests that E2F4, TAF7 and several lncRNAs function as transcriptional regulators in various signaling pathways. This study is the first global analysis of lncRNA and mRNA co-expression during RABV infection, provides deeper insight into the mechanism of RABV pathogenesis, and reveals promising candidate for future investigation.

Inhibition of long non-coding RNA HOTAIR enhances radiosensitivity via regulating autophagy in pancreatic cancer

Background

Resistance to radiation therapy is still a challenge for treatment of pancreatic cancer(PC). Long non-coding RNAs (lncRNA) HOTAIR has been found to play a oncogenic role in several cancers. However, the correlation between HOTAIR and radiotherapy in PC is still unclear.

Methods

TCGA data was collected to analyze the expression of HOTAIR and its relationship with PC progression. A series of functional experiments were conducted to explore the role of HOTAIR in PC radiosensitivity and its underlying molecular mechanisms.

Results

By the analysis of the TCGA data, we found HOTAIR expression in PC tissues was significantly higher than normal tissues and associated with tumor progression. The function analysis showed HOTAIR was enriched in biological regulation and response to stimulus. And in vitro study, the expression of HOTAIR was increased in PANC-1 and AsPC-1 cells after radiation. We identified that HOTAIR knockdown could enhance radiosensitivity and influence autophagy by up-regulating ATG7 expression in PC cells. By futher rescue experiments using rapamycin, activation of autophagy could reversed the the inhibition of cell proliferation and colony formation, as well as promotion of apoptosis mediated by HOTAIR knockdown, indicating that HOTAIR knockdown promoted radiosensitivity of PC cells by regulating autophagy.

Conclusion

Our finding revealed the the regulatory role of HOTAIR in radiosensitivity and provided a a new sight to improve radiotherapy effciency in PC.

Regulatory effects of lncRNAs and miRNAs on autophagy in malignant tumorigenesis

Autophagy is an important process in endogenous substrate degradation by lysosomes within cells, with a degree of evolutionary conservation. Like apoptosis and cell senescence, cell autophagy is a very important biological phenomenon involving the development and growth of biological processes. Abnormal autophagy may lead to tumorigenesis. In recent years, increasing studies have demonstrated that long non-coding RNAs (lncRNAs) and miRNAs can regulate cell autophagy by modulating targetting gene expression. In this review, we will provide an overview of lncRNAs and miRNAs in autophagy modulation and new insights into the underlying mechanisms, as well as their potential utilization in disease diagnosis, prognosis, and therapy.

Non-coding RNA in drug resistance of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has been one of the most highly lethal cancers. The acquisition of drug resistance accounts for the majority of poor effects of chemotherapy in HCC. Non-coding RNAs (ncRNAs) including miRNAs, long ncRNAs (lncRNAs), and circular RNA (circRNA) have been well-documented to participate in cancer occurrence and progression. Recently, multiple studies have highlighted the key roles of ncRNAs in chemoresistance of HCC. In addition, accumulating evidence has demonstrated that they can serve as biomarkers in diagnosis, treatment, and prognosis of HCC. In this review, we first overviewed up-to-date findings regarding miRNA and lncRNA in drug resistance of HCC, then summarized specific mechanisms that they modulate chemoresistance of HCC, and finally discussed their potential clinical application in overcoming the obstacle of HCC chemoresistance in the future.

N 6-Methyladenosine modification: a novel pharmacological target for anti-cancer drug development

N⁶-Methyladenosine (m⁶A) modification is the most pervasive modification of human mRNA molecules. It is reversible via regulation of m⁶A modification methyltransferase, demethylase and proteins that preferentially recognize m⁶A modification as “writers”, “erasers” and “readers”, respectively. Altered expression levels of the m⁶A modification key regulators substantially affect their function, leading to significant phenotype changes in the cell and organism. Recent studies have proved that the m⁶A modification plays significant roles in regulation of metabolism, stem cell self-renewal, and metastasis in a variety of human cancers. In this review, we describe the potential roles of m⁶A modification in human cancers and summarize their underlying molecular mechanisms. Moreover, we will highlight potential therapeutic approaches by targeting the key m⁶A modification regulators for cancer drug development.

CPEB1 mediates hepatocellular carcinoma cancer stemness and chemoresistance

Cancer stem cells (CSCs) are a subpopulation of cells within tumors that are believed to possess pluripotent properties and thought to be responsible for tumor initiation, progression, relapse and metastasis. Cytoplasmic polyadenylation element-binding protein 1 (CPEB1), a sequence-specific RNA-binding protein that regulates mRNA polyadenylation and translation, has been linked to cancer progression and metastasis. However, the involvement of CPEB1 in hepatocellular carcinoma (HCC) remains unclear. In this study, we have demonstrated that CPEB1 directly regulates sirtuin 1 (SIRT1) mRNA to mediate cancer stemness in HCC. Cancer stemness was analyzed by self-renewal ability, chemoresistance, metastasis, expression of stemness-related genes and CSC marker-positive cell populations. The results indicate that CPEB1 is downregulated in HCC. Overexpression of CPEB1 dramatically reduced HCC cell stemness, whereas silencing CPEB1 enhances it. Using site-directed mutagenesis, a luciferase reporter assay, and immunoprecipitation, we found that CPEB1 could directly target the 3′-UTR of SIRT1, control poly(A) tail length and suppress its translation to mediate cancer stemness in vitro and in vivo. Overall, our findings suggest that the negative regulation between CPEB1 and SIRT1 contributes to the suppression of cancer stemness in HCC. CPEB1 may have potential as a therapeutic target in HCC.

The Oncogenic Role of ARG1 in Progression and Metastasis of Hepatocellular Carcinoma

ARG1, which encodes Arginase1, is expressed in the liver cytoplasm and plays a major role in the hepatic urea cycle. The past research works shed light on the fact that ARG1 participates in anti-inflammation, tumor immunity, and immunosuppression-related diseases. Nevertheless, the concrete role and clinical significance of ARG1 in the progression of hepatocellular carcinoma (HCC) remain unclear. Herein, we aimed at examining the expression and clinicopathological significance of ARG1 in HCC, together with determining the effect of ARG1 on the progression and metastasis of HCC. In the current study, evaluation of the expression of ARG1 and clinicopathological significance of ARG1 was carried out in the human HCC tissues microarray, and the ARG1 overexpression vector and shRNA-ARG1 plasmids were constructed for the assessment of the concrete effect of ARG1 on cellular behaviors of Huh7 cells. As our data revealed, ARG1 was significantly downregulated in HCC, and the higher expression of ARG1 was positively correlated with more aggressive tumor growth, size, ALT, and GGT level. Significantly, we found that the high expression of ARG1 was correlated with poor DFS of HCC patients. Besides, in vitro study revealed that overexpression of ARG1 could enhance arginase activity, cell viability, migration, and invasion of Huh7 cells, and loss-of-function of ARG1 by shRNA interference could inhibit these cellular behaviors. Additionally, overexpression of ARG1 led to a significant increase in the expression of Vimentin, N-cadherin, and β-catenin both at protein and mRNA levels, which promotes the EMT process. On the other hand, these proteins' expression was significantly downregulated in ARG1 silenced Huh7 cells. Besides, the level of E-cadherin protein was upregulated in ARG1 knocked down cells. In conclusion, ARG1 might play a pivotal role as an oncogene in the progression of HCC through promoting the EMT process.

lncRNA involvement in hepatocellular carcinoma metastasis and prognosis

Eukaryotic lncRNAs are RNA molecules defined to be greater than 200 bp in length that are not translated to a protein and operate through several mechanisms, including participating in chromatin remodeling and methylation, influencing the integrity and stability of proteins and complexes, or acting as a sponge for miRNA inhibition. A number of recent studies have concentrated on the relationship between long non-coding RNAs (lncRNAs) and cancer. Hepatocellular carcinoma (HCC) is the most prevalent histological type of liver tumors, accounting for about 80 % of the cases worldwide. Lack of proper molecular markers for diagnosis of HCC and treatment evaluation is a significant problem. Dysregulated expression of HCC-related lncRNAs such as MEG-3, MALAT1, HULC, HOTAIR, and H19 have been identified and closely related with tumorigenesis, metastasis, prognosis and diagnosis. In this review, we summarized recent highlighted functions and molecular mechanisms of the most extensively studied lncRNAs in the pathophysiology of hepatocellular carcinoma and their potential for serving as probable therapeutic targets.

Subversion of cellular autophagy during virus infection: Insights from hepatitis B and hepatitis C viruses

Autophagy is a self-eating process, in which the damaged or excessed cell organelles and misfolded protein aggregates are removed from the cellular microenvironment. Autophagy is generally thought of as a pro-survival mechanism which is not only important for balancing energy supply at times of nutrient deprivation but also in the removal of various stress stimuli to ensure homeostasis. In addition to the target materials of "self" origin, autophagy can also eliminate intracellular pathogens and acts as a defense mechanism to curb infections. In addition, autophagy is linked to the host cell's innate immune response. However, viruses have evolved various strategies to manipulate and overtake host cell machinery to establish productive replication and maintain infectious process. In fact, replication of many viruses has been found to be autophagy-dependent and suppression of autophagy can potentially affect the viral replication. Thus, autophagy can either serve as an anti-viral defense mechanism or a pro-viral process that supports viral replication. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are known to co-opt cellular autophagy process as a pro-viral tool. Both viruses also induce mitophagy, which contributes to the establishment of chronic hepatitis. This review focuses on the roles of autophagy and mitophagy in the chronic liver disease pathogenesis associated with HBV and HCV infections.

LncRNA CDKN2B-AS1 promotes tumor growth and metastasis of human hepatocellular carcinoma by targeting let-7c-5p/NAP1L1 axis

Long non-coding RNAs (lncRNAs) show great potential as therapeutic targets in many diseases including hepatocellular carcinoma (HCC). Here, we aimed to investigate the clinical significance and function of lncRNA CDKN2B antisense RNA 1 (CDKN2B-AS1) in HCC. Here, we identified a novel oncogenic lncRNA CDKN2B-AS1, which was highly expressed in HCC and positively associated with large tumor size, microvascular invasion, high tumor grade, advanced tumor stage and reduced survival of HCC patients. CDKN2B-AS1 knockdown inhibited cell proliferation, migration and invasion, and induced G1 arrest and apoptosis of HCC cells in vitro, and CDKN2B-AS1 silencing suppressed tumor growth and metastasis of HCC in vivo. In accordance, CDKN2B-AS1 overexpression accelerated HCC cell growth and metastasis. Mechanistically, CDKN2B-AS1 promoted nucleosome assembly protein 1 like 1 (NAP1L1) expression by sponging let-7c-5p, thereby activated PI3K/AKT/mTOR signaling in HCC cells. Notably, NAP1L1 restoration abolished the effects of CDKN2B-AS1 silencing on HCC cell growth and metastasis. CDKN2B-AS1, an oncogenic lncRNA of HCC, promoted NAP1L1-mediated PI3K/AKT/mTOR signaling by acting as a molecular sponge of let-7c-5p. Our findings indicate that CDKN2B-AS1 may be a potential prognostic biomarker and a candidate target for HCC therapy.

Long Noncoding RNA LINC01619 Regulates MicroRNA-27a/Forkhead Box Protein O1 and Endoplasmic Reticulum Stress-Mediated Podocyte Injury in Diabetic Nephropathy

AIMS

Altered activities of long noncoding RNAs (lncRNAs) have been implicated in the regulation of microRNAs. microRNA-27a (miR-27a) upregulation has been shown to induce endoplasmic reticulum (ER) stress podocyte injury in diabetic nephropathy (DN). Herein, we aim to interrogate the mutually regulated network of miR-27a with long intergenic noncoding RNA 1619 (LINC01619) and the target gene.

RESULTS

LINC01619 downregulation was found in human DN renal biopsy tissues and contributed to proteinuria and diminished renal function. LINC01619 was expressed in podocyte cytoplasm and involved in ER stress signaling pathway. LINC01619 exerted biological function by serving as a "sponge" for miR-27a, which negatively targeted forkhead box protein O1 (FOXO1) and activated ER stress. In diabetic rats and high-glucose cultured podocytes, LINC01619 triggered oxidative stress and podocyte injuries as demonstrated by increased apoptosis, diffuse podocyte foot process effacement, and decreased renal function. Innovation and Conclusion: This study demonstrates that LINC01619 functions as a competing endogenous RNA and regulates miR-27a/FOXO1-mediated ER stress and podocyte injury in DN. Antioxid. Redox Signal. 29, 355-376.

Loss of sirtuin 1 and mitofusin 2 contributes to enhanced ischemia/reperfusion injury in aged livers

Ischemia/reperfusion (I/R) injury is a causative factor contributing to morbidity and mortality during liver resection and transplantation. Livers from elderly patients have a poorer recovery from these surgeries, indicating reduced reparative capacity with aging. Mechanisms underlying this age‐mediated hypersensitivity to I/R injury remain poorly understood. Here, we investigated how sirtuin 1 (SIRT1) and mitofusin 2 (MFN2) are affected by I/R in aged livers. Young (3 months) and old (23–26 months) male C57/BL6 mice were subjected to hepatic I/R in vivo. Primary hepatocytes isolated from each age group were also exposed to simulated in vitro I/R. Biochemical, genetic, and imaging analyses were performed to assess cell death, autophagy flux, mitophagy, and mitochondrial function. Compared to young mice, old livers showed accelerated liver injury following mild I/R. Reperfusion of old hepatocytes also showed necrosis, accompanied with defective autophagy, onset of the mitochondrial permeability transition, and mitochondrial dysfunction. Biochemical analysis indicated a near‐complete loss of both SIRT1 and MFN2 after I/R in old hepatocytes, which did not occur in young cells. Overexpression of either SIRT1 or MFN2 alone in old hepatocytes failed to mitigate I/R injury, while co‐overexpression of both proteins promoted autophagy and prevented mitochondrial dysfunction and cell death after reperfusion. Genetic approaches with deletion and point mutants revealed that SIRT1 deacetylated K655 and K662 residues in the C‐terminus of MFN2, leading to autophagy activation. The SIRT1‐MFN2 axis is pivotal during I/R recovery and may be a novel therapeutic target to reduce I/R injury in aged livers.

MicroRNA-29c restores cisplatin sensitivity in liver cancer through direct inhibition of sirtuin 1 expression

Liver cancer is one of the most prevalent human tumors in the world. Despite recent advances regarding the understanding of the molecular basis of liver cancer and the introduction of novel chemotherapeutic approaches, liver cancer remains associated with a poor prognosis. Sirtuin 1 (SIRT1) was identified to be abnormally upregulated in liver cancer. Dysregulation of microRNAs (miRs/miRNAs) is associated with a variety of types of cancer, and miRNAs may also serve a role in tumorigenesis and progression. The present study demonstrated that following the selection of the cisplatin chemoresistant HepG2 cell line, miR-29c is downregulated using reverse transcription-quantitative polymerase chain reaction. Furthermore, overexpression of miR-29c in cisplatin-resistant cancer cells was demonstrated to inhibit tumor cell proliferation and to promote apoptosis in vitro and in vivo, as well as restoring cisplatin chemosensitivity by using a cell counting assay, colony formation assay, Annexin V-fluorescein isothocyanate/propidium iodide apoptosis analysis, terminal deoxynucleotidyl transferase dUTP nick end labeling and xenograft tumors in nude mice. Mechanistically, according to bioinformatics analysis and a luciferase assay, miR-29c may directly target SIRT1 mRNA and repress SIRT1 expression, which is positively associated with the chemoresistance of liver cancer and may ultimately provide a novel therapeutic method.

HDAC3-mediated silencing of miR-451 decreases chemosensitivity of patients with metastatic castration-resistant prostate cancer by targeting NEDD9

Background:

Treatment of metastatic castration-resistant prostate cancer (mCRPC) with docetaxel often fails due to the emergence of chemoresistance. Thus, restoring chemosensitivity to docetaxel-based therapies remains a challenge in mCRPC treatment.

Methods:

microRNA (miR)-451 expression was measured in docetaxel-treated prostate cancer cells and tumor tissues by quantitative reverse-transcription polymerase chain reaction . Cell-counting kit 8 assay was performed to determine docetaxel chemoresistance. Neural-precursor-cell-expressed developmentally downregulated protein 9 (NEDD9) was identified as a novel target of miR-451 by dual-luciferase reporter system. Chromatin immunoprecipitation and co-immunoprecipitation assay were performed to confirm that histone deacetylase 3 (HDAC3)/Sp1 (a highly evolutionarily conserved transcription factor) interacted with the Sp1 binding sites in miR-451 promoter.

Results:

miR-451 was found to be silenced in docetaxel-treated prostate cancer cells and mCRPC tissues. Low miR-451 expression was closely associated with a high Gleason score, high Eastern Cooperative Oncology Group performance status score, visceral metastasis and poor prognosis. Low expression of miR-451 was significantly correlated with short progression-free survival (PFS) and overall survival (OS) according to Kaplan–Meier analysis, and miR-451 was determined to be an independent poor prognostic factor for PFS and OS in mCRPC patients by univariate and multivariate Cox regression analyses. NEDD9 was identified as a new and functional target of miR-451. Restoration of NEDD9 partially reversed the effects of miR-451 on enhancing chemosensitivity of prostate cancer cells. HDAC3 was confirmed to be involved in silencing of miR-451 expression in prostate cancer cells.

Conclusions:

The current data revealed a new HDAC3/Sp1/miR-451/NEDD9 signaling axis that regulates the chemosensitivity of prostate cancer cells and represents a novel therapeutic target for chemosensitizing mCRPC.

A Systematic Review of Long Noncoding RNAs in Hepatocellular Carcinoma: Molecular Mechanism and Clinical Implications

Hepatocellular carcinoma (HCC) has the second highest mortality rate worldwide among all cancers. Previous studies have revealed the significant involvement of long noncoding RNAs (lncRNAs) in numerous human cancers including HCC. Both oncogenic and tumor repressive lncRNAs have been identified and implicated in the complex process of hepatocarcinogenesis. They can be further explored as prospective diagnostic, prognostic, and therapeutic markers for HCC. An in-depth understanding of lncRNAs' mechanism in HCC is therefore required to fully explore their potential role. In the current review, we will concentrate on the underlying function, molecular mechanisms, and potential clinical implications of lncRNA in HCC.

Long non-coding RNA KCNQ1OT1 modulates oxaliplatin resistance in hepatocellular carcinoma through miR-7-5p/ ABCC1 axis

The underlying functions of long non-coding RNAs (lncRNAs) on chemoresistance in multiple cancers have been testified. However, the function and mechanism of lncRNAs on chemoresistance in hepatocellular carcinoma are still confused. In this study, we concentrated on the function and mechanism of KCNQ1OT1 on oxaliplatin resistance in hepatocellular carcinoma. Results showed that KCNQ1OT1 was significantly up-regulated in oxaliplatin-resistant HepG2 and Huh7 cells. Moreover, knockdown of KCNQ1OT1 inhibited the cell proliferation, migration, invasion and reduced the expression of drug-resistant gene (MRP5, MDR1, LRP1). Additionally, bioinformatics analysis and dual-luciferase reporter assay showed that miR-7-5p directly targeted the 3'-UTR of miR-7-5p and ABCC1 mRNA, indicating that KCNQ1OT1 regulated the expression of ABCC1 via endogenous sponging miR-7-5p. Conclusively, KCNQ1OT1 modulated oxaliplatin resistance in hepatocellular carcinoma through miR-7-5p/ABCC1 axis, indicating a novel approach for the treatment of hepatocellular carcinoma.

USP22 promotes resistance to EGFR-TKIs by preventing ubiquitination-mediated EGFR degradation in EGFR-mutant lung adenocarcinoma

As a newly discovered deubiquitinating enzyme, ubiquitin-specific protease 22 (USP22) is predictive of therapeutic outcomes in individual cancer patients. However, its clinical effects on malignancy and its roles in conferring resistance to EGFR-TKIs (epidermal growth factor receptor-tyrosine kinase inhibitors) in lung adenocarcinoma (ADC) remain largely unknown. Here, we showed that USP22 promotes cell proliferation, migration and invasion, and contributes to resistance to EGFR-TKIs in EGFR mutant lung ADC cells. Mechanistically, USP22 deubiquitinates EGFR localized on late endosomes, prevents ubiquitination mediated EGFR degradation and enhances recycling of EGFR after EGF stimulation. Additionally, USP22 sustained the activation of multiple EGFR downstream signaling pathways, including STAT3, AKT/mTOR and MEK/ERK pathways, in lung ADC cell lines H1975 and PC9. Furthermore, USP22 stabilizes EGFR protein expression, which correlates with USP22 expression in EGFR-mutant lung ADC patient samples. We are the first to demonstrate that silencing USP22 counteracts EGFR-TKIs resistance both in vitro and in vivo. We propose USP22 as a potential therapeutic target for EGFR-TKIs-resistant lung ADC.

The emergence of long non-coding RNAs in hepatocellular carcinoma: an update

Hepatocellular carcinoma (HCC) accounting for roughly 90% of all primary liver neoplasms is the sixth most frequent neoplasm and the second prominent reason of tumor fatality worldwide. As regulators of diverse biological processes, long non-coding RNAs (lncRNAs) are involved in onset and development of neoplasms. With the continuous booming of well-featured lncRNAs in HCC from 2016 to now, we reviewed the newly-presented comprehension about the relationship between lncRNAs and HCC in this study. To be specific, we summarized the overview function and study tools of lncRNAs, elaborated the roles of lncRNAs in HCC, and sketched the molecule mechanisms of lncRNAs in HCC. In addition, the application of lncRNAs serving as biomarkers in early diagnosis and outcome prediction of HCC patients was highlighted.

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.

MiR-490-3p inhibits autophagy via targeting ATG7 in hepatocellular carcinoma

The miR-490-3p was transfected into HepG2 cells to explore the correlation between miR-490-3p and hepatocellular carcinoma cell proliferation, apoptosis, and autophagy and its downstream target gene ATG7. Then we could possibly provide a mechanism for the treatment of hepatocellular carcinoma. MiR-490-3p was screened out by fold change > 4 and P < 0.01 using gene microarray data. The expression level of miR-490-3p was tested by qRT-PCR and the prognosis analysis was achieved by using TCGA data. The cell proliferation was tested via colony formation assay and CCK-8 after the miR-490-3p mimics were transfected into HepG2 cells; the variations of cell cycle and apoptosis was examined by flow cytometry assay; the number of autophagosome was observed by electron microscopy and the changes of autophagy-relative protein LC-II and LC-I as well as their ratio was tested by western blot. MiR-490-3p is low expressed in hepatocellular carcinoma cell lines and tissues. The results of TCGA showed that miR-490-3p high expression indicated better prognosis. After HepG2 cells were transfected with miR-490-3p mimics, cell viability was increased, cell proliferation was enhanced, cell cycle was blocked in G0/G1 phase, cell apoptosis rate was increased, the number of autophagosomes was reduced, autophagy-associated protein LC-II was decreased, and LC-I was increased and their ratio was decreased. After 3-MA was added, cell proliferation was declined, cell apoptosis rate was increased. Besides, the autophagy was inhibited by knocking down the ATG7, which promoted the cell apoptosis. MiR-490-3p could suppress cell proliferation, retard cell cycle and upgrade cell apoptosis by inhibiting autophagy in HCC cells via targeting ATG7. © 2018 IUBMB Life, 70(6):468-478, 2018.