miR-508 Defines the Stem-like/Mesenchymal Subtype in Colorectal Cancer

SALL4 in gastrointestinal tract cancers: upstream and downstream regulatory mechanisms

Effective therapeutic targets and early diagnosis are major challenges in the treatment of gastrointestinal tract (GIT) cancers. SALL4 is a well-known transcription factor that is involved in organogenesis during embryonic development. Previous studies have revealed that SALL4 regulates cell proliferation, survival, and migration and maintains stem cell function in mature cells. Additionally, SALL4 overexpression is associated with tumorigenesis. Despite its characterization as a biomarker in various cancers, the role of SALL4 in GIT cancers and the underlying mechanisms are unclear. We describe the functions of SALL4 in GIT cancers and discuss its upstream/downstream genes and pathways associated with each cancer. We also consider the possibility of targeting these genes or pathways as potential therapeutic options for GIT cancers.

miR-508-5p serves as an anti-oncogene by targeting S100A16 to regulate AKT signaling and epithelial-mesenchymal transition process in lung adenocarcinoma cells

BACKGROUND

Our aim was to expose the effect of miR-508-5p on the developmental and biological behaviour of lung adenocarcinoma (LUAC).

METHODS

The KM plotter was used to analyze the survival significance of miR-508-5p and S100A16 expression in LUAC patients. qRT-PCR was performed to detect the expression of miR-508-5p and S100A16 in LUAC tissue and LUAC cell lines. CCK8, colony formation and Transwell were performed to evaluate the effects of miR-508-5p and S100A16 on cell proliferation and metastasis. Dual luciferase reporter assay was used to verify that S100A16 were targets of miR-508-5p. Western blot analysis was performed to analyze protein expression.

RESULTS

Results showed that low miR-508-5p expression in LUAC tissues indicated poorer overall survival of LUAC patients and miR-508-5p was downregulated in LUAC cell lines compared to the normal human lung epithelial cell line. miR-508-5p mimics could inhibit A549 cell proliferation and metastasis abilities, while miR-508-5p Antagomir showed the opposite effect. We identified S100A16 as one direct target of miR-508-5p, and rescuing S100A16 expression could reverse the effect of miR-508-5p mimics on A549 cell proliferation and metastasis. miR-508-5p could involve the coordination of AKT signaling and epithelial-mesenchymal transition (EMT) progress using western-blot assays and rescuing S100A16 expression could reverse the inhibited AKT signaling and EMT progress induced by miR-508-5p mimics.

CONCLUSIONS

We found that miR-508-5p targeted S100A16 to regulate AKT signaling and EMT progress in A549 cells, resulting in impaired cell proliferation and metastasis activity, suggesting that miR-508-5p might be a promising therapeutic target and an important diagnostic and prognostic marker for improved LUAC therapeutic schedule.

Long Non-Coding RNAs as Potential Regulators of EMT-Related Transcription Factors in Colorectal Cancer—A Systematic Review and Bioinformatics Analysis

Simple Summary

Emerging evidence highlights long non-coding RNAs as important regulators of epithelial–mesenchymal transition. Numerous studies have attempted to define their possible diagnostic, prognostic and therapeutic values in various human cancers. The aim of this review is to summarize long non-coding RNAs involved in the regulation of epithelial–mesenchymal transition in colorectal carcinoma. Additional candidate long non-coding RNAs are identified through a bioinformatics analysis.

Abstract

Epithelial–mesenchymal transition (EMT) plays a pivotal role in carcinogenesis, influencing cancer progression, metastases, stemness, immune evasion, metabolic reprogramming and therapeutic resistance. EMT in most carcinomas, including colorectal carcinoma (CRC), is only partial, and can be evidenced by identification of the underlying molecular drivers and their regulatory molecules. During EMT, cellular reprogramming is orchestrated by core EMT transcription factors (EMT-TFs), namely ZEB1/2, TWIST1/2, SNAI1 (SNAIL) and SNAI2 (SLUG). While microRNAs have been clearly defined as regulators of EMT, the role of long non-coding RNAs (lncRNAs) in EMT is poorly defined and controversial. Determining the role of lncRNAs in EMT remains a challenge, because they are involved in a number of cellular pathways and are operating through various mechanisms. Adding to the complexity, some lncRNAs have controversial functions across different tumor types, acting as EMT promotors in some tumors and as EMT suppressors in others. The aim of this review is to summarize the role of lncRNAs involved in the regulation of EMT-TFs in human CRC. Additional candidate lncRNAs were identified through a bioinformatics analysis.

LncRNAs, the Molecules Involved in Communications With Colorectal Cancer Stem Cells

Colorectal cancer stem cells (CRCSCs) can actively self-renew, as well as having multidirectional differentiation and tumor regeneration abilities. Because the high functional activities of CRCSCs are associated with low cure rates in patients with colorectal cancer, efforts have sought to determine the function and regulatory mechanisms of CRCSCs. To date, however, the potential regulatory mechanisms of CRCSCs remain incompletely understood. Many non-coding genes are involved in tumor invasion and spread through their regulation of CRCSCs, with long non-coding RNAs (lncRNAs) being important non-coding RNAs. LncRNAs may be involved in the colorectal cancer development and drug resistance through their regulation of CRCSCs. This review systematically evaluates the latest research on the ability of lncRNAs to regulate CRCSC signaling pathways and the involvement of these lncRNAs in colorectal cancer promotion and suppression. The regulatory network of lncRNAs in the CRCSC signaling pathway has been determined. Further analysis of the potential clinical applications of lncRNAs as novel clinical diagnostic and prognostic biomarkers and therapeutic targets for colorectal cancer may provide new ideas and protocols for the prevention and treatment of colorectal cancer.

The Relationship Between the Network of Non-coding RNAs-Molecular Targets and N6-Methyladenosine Modification in Colorectal Cancer

Recent accumulating researches implicate that non-coding RNAs (ncRNAs) including microRNA (miRNA), circular RNA (circRNA), and long non-coding RNA (lncRNAs) play crucial roles in colorectal cancer (CRC) initiation and development. Notably, N6-methyladenosine (m⁶A) methylation, the critical posttranscriptional modulators, exerts various functions in ncRNA metabolism such as stability and degradation. However, the interaction regulation network among ncRNAs and the interplay with m⁶A-related regulators has not been well documented, particularly in CRC. Here, we summarize the interaction networks and sub-networks of ncRNAs in CRC based on a data-driven approach from the publications (IF > 6) in the last quinquennium (2016–2021). Further, we extend the regulatory pattern between the core m⁶A regulators and m⁶A-related ncRNAs in the context of CRC metastasis and progression. Thus, our review will highlight the clinical potential of ncRNAs and m⁶A modifiers as promising biomarkers and therapeutic targets for improving the diagnostic precision and treatment of CRC.

Molecular features and gene expression signature of metastatic colorectal cancer (Review)

Uncontrollable metastatic outgrowth process is the leading cause of mortality worldwide, even in the case of colorectal cancer. Colorectal cancer (CRC) accounts for approximately 10% of all annually diagnosed cancers and 50% of CRC patients will develop metastases in the course of disease. Most patients with metastatic CRC have incurable disease. Even if patients undergo resection of liver metastases, the 5‑year survival rate ranges from 25 to 58%. Next‑generation sequencing of tumour specimens from large colorectal cancer patient cohorts has led to major advances in elucidating the genomic landscape of these tumours and paired metastases. The expression profiles of primary CRC and their metastatic lesions at both the gene and pathway levels were compared and led to the selection of early driver genes responsible for carcinogenesis and metastasis‑specific genes that increased the metastatic process. The genetic, transcriptional and epigenetic alteration encoded by these genes and their combination influence many pivotal signalling pathways, enabling the dissemination and outgrowth in distant organs. Therapeutic regimens affecting several different active pathways may have important implications for therapeutic efficacy.

ChrXq27.3 miRNA cluster functions in cancer development

MicroRNAs (miRNAs) regulate the expression of their target genes post-transcriptionally; thus, they are deeply involved in fundamental biological processes. miRNA clusters contain two or more miRNA-encoding genes, and these miRNAs are usually coexpressed due to common expression mechanisms. Therefore, miRNA clusters are effective modulators of biological pathways by the members coordinately regulating their multiple target genes, and an miRNA cluster located on the X chromosome q27.3 region has received much attention in cancer research recently. In this review, we discuss the novel findings of the chrXq27.3 miRNA cluster in various types of cancer.

The chrXq27.3 miRNA cluster contains 30 mature miRNAs synthesized from 22 miRNA-encoding genes in an ~ 1.3-Mb region. The expressions of these miRNAs are usually negligible in many normal tissues, with the male reproductive system being an exception. In cancer tissues, each miRNA is dysregulated, compared with in adjacent normal tissues. The miRNA-encoding genes are not uniformly distributed in the region, and they are further divided into two groups (the miR-506-514 and miR-888-892 groups) according to their location on the genome. Most of the miRNAs in the former group are tumor-suppressive miRNAs that are further downregulated in various cancers compared with normal tissues. miR-506-3p in particular is the most well-known miRNA in this cluster, and it has various tumor-suppressive functions associated with the epithelial–mesenchymal transition, proliferation, and drug resistance. Moreover, other miRNAs, such as miR-508-3p and miR-509-3p, have similar tumor-suppressive effects. Hence, the expression of these miRNAs is clinically favorable as prognostic factors in various cancers. However, the functions of the latter group are less understood. In the latter group, miR-888-5p displays oncogenic functions, whereas miR-892b is tumor suppressive. Therefore, the functions of the miR-888–892 group are considered to be cell type- or tissue-specific.

In conclusion, the chrXq27.3 miRNA cluster is a critical regulator of cancer progression, and the miRNAs themselves, their regulatory mechanisms, and their target genes might be promising therapeutic targets.

Expression of the chrXq27.3 miRNA cluster in recurrent ovarian clear cell carcinoma and its impact on cisplatin resistance

Ovarian clear cell carcinoma (OCCC) is a histological subtype of epithelial ovarian cancer and exhibits dismal prognosis due to chemoresistance. Moreover, only few effective therapeutic options exist for patients with recurrent OCCC, and an understanding of its molecular characteristics is essential for the development of novel therapeutic approaches. In the present study, we investigated unique MicroRNAs (miRNA) profiles in recurrent/metastatic OCCC and the role of miRNAs in cisplatin resistance. Comprehensive miRNA sequencing revealed that expression of several miRNAs, including miR-508-3p, miR-509-3p, miR-509-3-5p, and miR-514a-3p was remarkably less in recurrent cancer tissues when compared with that in paired primary cancer tissues. These miRNAs are located in the chrXq27.3 region on the genome. Moreover, its expression was negative in omental metastases in two patients with advanced OCCC. In vitro analyses revealed that overexpression of miR-509-3p and miR-509-3-5p reversed cisplatin resistance and yes-associated protein 1 (YAP1) was partially responsible for the resistance. Immunohistochemistry revealed that YAP1 expression was inversely correlated with the chrXq27.3 miRNA cluster expression. In conclusion, these findings suggest that alteration of the chrXq27.3 miRNA cluster could play a critical role in chemoresistance and miRNAs in the cluster and their target genes can be potential therapeutic targets.

YY1-mediated up-regulation of lncRNA LINC00466 facilitates glioma progression via miR-508/CHEK1

BACKGROUND

The abnormal expression of lncRNA LINC00466 (LINC00466) has been demonstrated in several tumor types. However, the expression pattern and functions of LINC00466 in glioma remain uninvestigated.

METHODS

A reverse transcriptase-polymerase chain reaction (RT-PCR) was utilized to analyze LINC00466 in human glioma tissues and cell lines. Luciferase reporter assays were performed to explore whether YY1 could bind to the promoter region of LINC00466. Cell counting kit-8, flow cytometry, colony-formation, transwell migration and invasion assays were carried out to determine the involvement of INC00466 in glioma. Luciferase assays and pulldown assays were conducted to verify the binding sites.

RESULTS

We report that LINC00466 expression is increased in glioma cells and tissues. YY1 transcription factor (YY1) can bind directly to the LINC00466 promoter region. Clinical studies revealed that the elevated expression of LINC00466 is closely correlated with an advanced World Health Organization grade (p = 0.008), Karnofsky Performance Status score (p = 0.004) and a short overall survival (p = 0.0035) of glioma patients. Functional assays revealed that LINC00466 knockdown distinctly suppresses glioma cell proliferation, migration, invasion and epithelial-mesenchymal progress, and also promotes apoptosis. Moreover, dual-luciferase reporter assays indicated that LINC00466 acts as an endogenous sponge via binding to miR-508 and decreasing its expression. Luciferase assays and RT-PCR assays demonstrated that checkpoint kinase 1 (CHEK1) is a target of miR-508, and LINC00466 modulates CHEK1 levels by competing for miR-508. LINC00466 may exhibit its anti-oncogenic roles through targeting the miR-508/CHEK1 axis.

CONCLUSIONS

Our findings identified a novel glioma-related long non-coding RNA, LINC00466, which may provide a potential novel prognostic and therapeutic target for glioma.

2-Amino-1,3-benzothiazole-6-carboxamide Preferentially Binds the Tandem Mismatch Motif r(UY:GA)

RNA helices are often punctuated with non-Watson-Crick features that may be targeted by chemical compounds, but progress toward identifying such compounds has been slow. We embedded a tandem UU:GA mismatch motif (5'-UG-3':5'-AU-3') within an RNA hairpin stem to identify compounds that bind the motif specifically. The three-dimensional structure of the RNA hairpin and its interaction with a small molecule identified through virtual screening are presented. The G-A mismatch forms a sheared pair upon which the U-U base pair stacks. The hydrogen bond configuration of the U-U pair involves O2 of the U adjacent to the G and O4 of the U adjacent to the A. The G-A and U-U pairs are flanked by A-U and G-C base pairs, respectively, and the stability of the mismatch is greater than when the motif is within the context of other flanking base pairs or when the 5'-3' orientation of the G-A and U-U pairs is swapped. Residual dipolar coupling constants were used to generate an ensemble of structures against which a virtual screen of 64480 small molecules was performed. The tandem mismatch was found to be specific for one compound, 2-amino-1,3-benzothiazole-6-carboxamide, which binds with moderate affinity but extends the motif to include the flanking A-U and G-C base pairs. The finding that the affinity for the UU:GA mismatch is dependent on flanking sequence emphasizes the importance of the motif context and potentially increases the number of small noncanonical features within RNA that can be specifically targeted by small molecules.

Hypoxia-induced epithelial to mesenchymal transition in cancer

A common feature of many solid tumors is low oxygen conditions due to inadequate blood supply. Hypoxia induces hypoxia inducible factor (HIF) stabilization and downstream signaling. This signaling has pleiotropic roles in cancers, including the promotion of cellular proliferation, changes in metabolism, and induction of angiogenesis. In addition, hypoxia is becoming recognized as an important driver of epithelial-to-mesenchymal (EMT) in cancer. During EMT, epithelial cells lose their typical polarized states and transition to a more mobile mesenchymal phenotype. Hypoxia induces this transition by modulating EMT signaling pathways, inducing EMT transcription factor activity, and regulating miRNA networks. As both hypoxia and EMT modulate the tumor microenvironment (TME) and are associated with immunosuppression, we also explore how these pathways may impact response to immuno-oncology therapeutics.

Integrative analysis of circRNAs, miRNAs, and mRNAs profiles to reveal ceRNAs networks in chicken intramuscular and abdominal adipogenesis

BACKGROUND

Tissue-specific fat deposition is regulated by a series of complex regulatory mechanisms. Reports indicate that epigenetic regulators, such as circular RNAs (circRNAs), are crucial in diseases progression, animal development, metabolism, and adipogenesis. In this study, to assess the functional roles of circRNAs in adipogenesis and tissue-specific fat deposition, we comprehensively analyzed the Ribo-Zero RNA-Seq and miRNAs data during chicken intramuscular and abdominal adipogenic differentiation.

RESULTS

circRNAs and miRNAs profiles during chicken adipogenic differentiation were found in adipocytes derived from various adipose tissues. It was also discovered that high levels of downregulated miRNAs potentially promote adipogenesis by activating their target genes which are associated with fatty acid metabolism and adipogenic differentiation. Through analysis of the correlation between the expression levels of circRNAs and adipogenic genes, as well as the dynamic expression patterns of circRNAs during adipogenic differentiation, several candidate circRNAs were identified. Moreover, competing endogenous RNA (ceRNAs) networks were constructed during chicken intramuscular and abdominal adipogenesis by combining miRNAs with mRNAs data. Several candidate circRNAs potentially influence adipogenesis by regulating miRNAs via PPAR and fatty acid metabolism-related pathways were identified, such as circLCLAT1, circFNDC3AL, circCLEC19A and circARMH1.

CONCLUSION

In conclusion, our findings reveal that circRNAs and the circRNA-miRNAs-mRNAs-ceRNAs network may play important roles in chicken adipocytes differentiation and tissue-specific fat deposition.

LINC00511 contributes to glioblastoma tumorigenesis and epithelial-mesenchymal transition via LINC00511/miR-524-5p/YB1/ZEB1 positive feedback loop

Tumour invasion is closely related to the prognosis and recurrence of glioblastoma multiforme and partially attributes to epithelial‐mesenchymal transition. Long intergenic non‐coding RNA 00511 (LINC00511) plays a pivotal role in tumour; however, the role of LINC00511 in GBM, especially in the epigenetic molecular regulation mechanism of EMT, is still unclear. Here, we found that LINC00511 was up‐regulated in GBM tissues and relatively high LINC00511 expression predicted poorer prognosis. Moreover, ectopic LINC00511 enhanced GBM cells proliferation, EMT, migration and invasion, whereas LINC00511 knockdown had the opposite effects. Mechanistically, we confirmed that ZEB1 acted as a transcription factor for LINC00511 in GBM cells. Subsequently, we found that LINC00511 served as a competing endogenous RNA that sponged miR‐524‐5p to indirectly regulate YB1, whereas, up‐regulated YB1 promoted ZEB1 expression, which inversely facilitated LINC00511 expression. Finally, orthotopic xenograft models were performed to further demonstrate the LINC00511 on GBM tumorigenesis. This study demonstrates that a LINC00511/miR‐524‐5p/YB1/ZEB1 positive feedback loop provides potential therapeutic targets for GBM progression.

Insights into Biological Role of LncRNAs in Epithelial-Mesenchymal Transition

Long non-coding RNAs (lncRNAs) are versatile regulators of gene expression and play crucial roles in diverse biological processes. Epithelial-mesenchymal transition (EMT) is a cellular program that drives plasticity during embryogenesis, wound healing, and malignant progression. Increasing evidence shows that lncRNAs orchestrate multiple cellular processes by modulating EMT in diverse cell types. Dysregulated lncRNAs that can impact epithelial plasticity by affecting different EMT markers and target genes have been identified. However, our understanding of the landscape of lncRNAs important in EMT is far from complete. Here, we summarize recent findings on the mechanisms and roles of lncRNAs in EMT and elaborate on how lncRNAs can modulate EMT by interacting with RNA, DNA, or proteins in epigenetic, transcriptional, and post-transcriptional regulation. This review also highlights significant EMT pathways that may be altered by diverse lncRNAs, thereby suggesting their therapeutic potential.

Inflammatory Micro-environment Contributes to Stemness Properties and Metastatic Potential of HCC via the NF-κB/miR-497/SALL4 Axis

Increasing evidence has demonstrated the essential role of inflammatory micro-environment in tumorigenesis and tumor progression. Some cancer cells in tumor maintain typical stemness properties and, with the capacity of self-renewal, are thought to be crucial for the initiation and maintenance of tumors as well as their metastasis. Although both inflammatory micro-environment and stemness properties played crucial roles in tumor initiation and development, currently it is still unclear whether and how the inflammatory micro-environment promotes cancer stemness properties. Here, we show the first evidence that the inflammatory micro-environment promotes the stemness properties and metastatic potential of hepatocellular carcinoma (HCC) via the NF-κB/miR-497/SALL4 axis. We discover that miR-497 directly targets SALL4, negatively regulates its expression, and further inhibits the self-renewal and metastasis of HCC; more importantly, inflammatory factor TNF-α inhibits the expression of miR-497 via NF-kB-mediated negative transcriptional regulation and simultaneously upregulates the expression of SALL4 and promotes the self-renewal and metastasis phenotypes of HCC cells. Moreover, lower expression of miR-497 is significantly associated with poor prognosis in HCC patients. Taken together, our findings not only revealed a novel signaling pathway (NF-κB/miR-497/SALL4 axis) to connect inflammation with stemness properties, and clarified the molecular mechanisms underlying the inflammation-mediated self-renewal and metastasis phenotypes, but also provided novel molecular targets for developing new anticancer strategies.

The Role of MicroRNAs in the Regulation of Gastric Cancer Stem Cells: A Meta-Analysis of the Current Status

Gastric cancer (GC) remains one of the major causes of cancer-related mortality worldwide. As for other types of cancers, several limitations to the success of current therapeutic GC treatments may be due to cancer drug resistance that leads to tumor recurrence and metastasis. Increasing evidence suggests that cancer stem cells (CSCs) are among the major causative factors of cancer treatment failure. The research of molecular CSC mechanisms and the regulation of their properties have been intensively studied. To date, molecular gastric cancer stem cell (GCSC) characterization remains largely incomplete. Among the GCSC-targeting approaches to overcome tumor progression, recent studies have focused their attention on microRNA (miRNA). The miRNAs are short non-coding RNAs which play an important role in the regulation of numerous cellular processes through the modulation of their target gene expression. In this review, we summarize and discuss recent findings on the role of miRNAs in GCSC regulation. In addition, we perform a meta-analysis aimed to identify novel miRNAs involved in GCSC homeostasis.

MicroRNA-508 is downregulated in clear cell renal cell carcinoma and targets ZEB1 to suppress cell proliferation and invasion

Recent studies have identified several microRNAs (miRNAs/miRs) that are dysregulated in clear cell renal cell carcinoma (ccRCC), and their dysregulation may serve important roles in the occurrence and development of ccRCC. Therefore, understanding the expression pattern and functional roles of miRNAs in ccRCC may facilitate the identification of novel therapeutic targets for the treatment of ccRCC. In the current study, reverse transcription-quantitative polymerase chain reaction was used to determine miR-508 expression levels in ccRCC tissue samples and cell lines. The cell counting kit-8 and in vitro Transwell invasion assays were used to examine the effects of miR-508 overexpression on ccRCC cell proliferation and invasion, respectively. In addition, bioinformatics analysis and dual-luciferase reporter gene assays were used to investigate the underlying mechanism of miR-508 in ccRCC cells. Furthermore, the regulatory role of miR-508 on zinc finger E-box-binding homeobox 1 (ZEB1) mRNA and protein expression in ccRCC cells was investigated using RT-qPCR and western blot analysis, respectively. Additionally, the association between miR-508 and ZEB1 expression in ccRCC tissue samples was examined. Rescue experiments were performed to determine whether the tumor suppressive effects of miR-508 may be mediated by ZEB1 in ccRCC cells. The results of the current study demonstrated that miR-508 expression was significantly downregulated in ccRCC tissue samples and cell lines. In addition, miR-508 overexpression significantly decreased the proliferation and invasion of ccRCC cells. ZEB1 was identified as a direct target gene of miR-508 in ccRCC cells and the relative expression level of ZEB1 mRNA was significantly increased in ccRCC tissue samples. Furthermore, a negative correlation between miR-508 and ZEB1 expression was identified in ccRCC tissues. ZEB1 knockdown exhibited a functional role similar to miR-508 overexpression in ccRCC cells, and restoration of ZEB1 expression significantly reversed the inhibitory effects of miR-508 on the malignant phenotype of ccRCC cells. Taken together, the results of the current study demonstrated that miR-508 may serve a tumor suppressive role in ccRCC via direct targeting of ZEB1. MiR-508 may present a novel and efficient therapeutic target for the treatment of patients with ccRCC.

Emerging microRNA biomarkers for colorectal cancer diagnosis and prognosis

MicroRNAs (miRNAs) are one abundant class of small, endogenous non-coding RNAs, which regulate various biological processes by inhibiting expression of target genes. miRNAs have important functional roles in carcinogenesis and development of colorectal cancer (CRC), and emerging evidence has indicated the feasibility of miRNAs as robust cancer biomarkers. This review summarizes the progress in miRNA-related research, including study of its oncogene or tumour-suppressor roles and the advantages of miRNA biomarkers for CRC diagnosis, treatment and recurrence prediction. Along with analytical technique improvements in miRNA research, use of the emerging extracellular miRNAs is feasible for CRC diagnosis and prognosis.

RAB31 Targeted by MiR-30c-2-3p Regulates the GLI1 Signaling Pathway, Affecting Gastric Cancer Cell Proliferation and Apoptosis

Background: Gastric cancer (GC), one of the most common cancers worldwide, is highly malignant and fatal. Ras-related protein in brain 31 (RAB31), a member of the RAB family of oncogenes, participates in the process of carcinogenesis and cancer development; however, its role in GC progression is unknown.

Methods: In our study, 90 pairs of tissue microarrays were used to measure the levels of RAB31 protein by immunochemistry, and 22 pairs of fresh tissue were used to measure the levels of RAB31 mRNA by quantitative PCR. We also investigated the effects of RAB31 on tumor growth both in vitro and in vivo.

Results: RAB31 was overexpressed in GC tissues, and its overexpression predicted poor survival in patients. In a nude mouse model, depletion of RAB31 inhibited tumor growth. In vitro, silencing of RAB31 suppressed cell viability, promoted cell cycle arrest, enhanced apoptosis, and affected the expression of cell cycle and apoptotic proteins; these effects were mediated by glioma-associated oncogene homolog 1 (GLI1). Co-immunoprecipitation and immunofluorescence assays confirmed that RAB31 interacted with GLI1. In addition, luciferase reporter assays and Western blotting showed that microRNA-30c-2-3p modulated the RAB31/GLI1 pathway by targeting the 3′-untranslated region of RAB31.

Conclusions: Collectively, these data show that RAB31 is regulated by microRNA-30c-2-3p, and functions as an oncogene in GC tumorigenesis and development by interacting with GLI1. Therefore, targeting the miR-30c-2-3p/RAB31/GLI1 axis may be a therapeutic intervention for gastric cancer.

The Long Noncoding RNA MEG3 and its Target miR-147 Regulate JAK/STAT Pathway in Advanced Chronic Myeloid Leukemia

Background

Long non-coding (lnc) RNAs plays an important role in chronic myeloid leukemia (CML). In this study, we aimed to uncover the mechanism of the lncRNA maternally expressed 3 (MEG3) and its target microRNA-147 (miR-147) in CML.

Methods

Sixty CML patients and 10 healthy donors were included in the study. The methylation of MEG3 and miR-147 promoter was determined by methylation-specific PCR. The relationship of MEG3 and miR-147 was explored by luciferase assay. The interactions of proteins were studied by RNA pull-down assay, RNA immunoprecipitation and co-immunoprecipitation.

Findings

Patients in accelerated phase CML (CML-AP) and blast phase CML (CML-BP) showed lower expressions of MEG3 and miR-147 and higher expressions of DNMT1, DNMT3B, MBD2, MECP2 and HDAC1 compared to the controls. These patients also showed a higher degree of methylation of MEG3 and miR-147 while there was a reduction after chidamide treatment. Furthermore, the overexpression of MEG3 and miR-147 inhibited cell proliferation both in vivo and in vitro, promoted apoptosis and decreased the expressions of DNMT1, DNMT3A, DNMT3B, MBD2, HDAC1 and MECP2. We also found MEG3 interacted with DNMT1, JAK2, STAT3, HDAC1, and TYK2, and JAK2 was bound to STAT3, STAT5 and MYC. More interestingly, JAK2 was bound to TYK2 by the bridge of MEG3.

Interpretation

LncRNA MEG3 and its target miR-147 may serve as a novel therapeutic target for CML blast crisis, and chidamide might have a potential clinical application in treating CML blast crisis.

The distinct role of strand-specific miR-514b-3p and miR-514b-5p in colorectal cancer metastasis

The abnormal expression of microRNAs (miRNAs) in colorectal cancer (CRC) progression has been widely investigated. It was reported that the same hairpin RNA structure could generate mature products from each strand, termed 5p and 3p, which binds different target mRNAs. Here, we explored the expression, functions, and mechanisms of miR-514b-3p and miR-514b-5p in CRC cells and tissues. We found that miR-514b-3p was significantly down-regulated in CRC samples, and the ratio of miR-514b-3p/miR-514b-5p increased from advanced CRC, early CRC to matched normal colorectal tissues. Follow-up functional experiments illustrated that miR-514b-3p and miR-514b-5p had distinct effects through interacting with different target genes: MiR-514b-3p reduced CRC cell migration, invasion and drug resistance through increasing epithelial marker and decreasing mesenchymal marker expressions, conversely, miR-514b-5p exerted its pro-metastatic properties in CRC by promoting EMT progression. MiR-514b-3p overexpressing CRC cells developed tumors more slowly in mice compared with control cells, however, miR-514b-5p accelerated tumor metastasis. Overall, our data indicated that though miR-514b-3p and miR-514b-5p were transcribed from the same RNA hairpin, each microRNA has distinct effect on CRC metastasis.