Construction and identification of lncRNA/circRNA-coregulated ceRNA networks in gemcitabine-resistant bladder carcinoma.

OBJECTIVES: To explore the regulatory networks that underlie the development of chemoresistance in bladder cancer. METHODS: We analyzed profiles of differentially expressed long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), microRNAs (miRNAs) and messenger RNA (mRNAs) in gemcitabine-resistant/sensitive bladder cancer cells using next-generation sequencing data. RESULTS: Hundreds of differentially expressed lncRNAs and miRNAs and thousands of circRNAs and mRNAs were identified. Bioinformatics analysis revealed the chromosomal localizations, classification and coexpression of mRNAs, as well as candidates for cis and trans regulation by lncRNAs. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of differentially expressed mRNAs and circRNAs indicated important functional roles of coregulated RNAs, thus establishing competing endogenous RNA (ceRNA) and protein-protein interactions networks that may underlie chemoresistance in bladder cancer. We demonstrated that lncRNA LINP1 can act as a ceRNA by inhibiting miR-193a-5p to increase TP73 expression; and that lncRNA ESRG and hsa_circ_0075881 can simultaneously bind miR-324-3p to increase ST6GAL1 expression. Modulation of ceRNA network components using ablation and overexpression approaches contributed to gemcitabine resistance in bladder cancer cells. CONCLUSIONS: These results elucidate mechanisms by which lncRNAs and circRNAs coregulate the development of bladder cancer cell resistance to gemcitabine, thus laying the foundation for future research to identify biomarkers and disease targets.

IGF2BP2-induced circRUNX1 facilitates the growth and metastasis of esophageal squamous cell carcinoma through miR-449b-5p/FOXP3 axis.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is one of the most common digestive malignancies with relatively high morbidity and mortality. Emerging evidence suggests circular RNAs (circRNAs) play critical roles in tumor cell malignancy. However, the biological function and clinical significance of many circRNAs in ESCC remain elusive. METHODS: The expression level and clinical implication of circRUNX1 in ESCC tissues were evaluated using qRT-PCR. In vitro and in vivo functional studies were conducted to investigate the underlying biological effects of circRUNX1 on ESCC cell growth and metastasis. Moreover, bioinformatics analysis, RNA sequencing (RNA-seq), RNA immunoprecipitation (RIP) assays, dual-luciferase reporter assays, and rescue experiments were performed to explore the relationships between circRUNX1, miR-449b-5p, Forkhead box protein P3 (FOXP3), and insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). RESULTS: CircRUNX1 was found to be significantly up-regulated in ESCC tissues and associated with TNM stage and differentiation grade. Functionally, circRUNX1 promoted ESCC cell proliferation and metastasis in vitro and in vivo. CircRUNX1 enhanced FOXP3 expression by competitively sponging miR-449b-5p. Notably, both miR-449b-5p mimics and FOXP3 knockdown restored the effects of circRUNX1 overexpression on cell proliferation and metastasis. Furthermore, IGF2BP2 binding to circRUNX1 prevented its degradation. CONCLUSIONS: IGF2BP2 mediated circRUNX1 functions as an oncogenic factor to facilitate ESCC progression through the miR-449b-5p/FOXP3 axis, implying that circRUNX1 has the potential to be a promising diagnostic marker and therapeutic target for ESCC patients.

Novel insights into m6A modification of coding and non-coding RNAs in tumor biology: From molecular mechanisms to therapeutic significance.

Accumulating evidence has revealed that m6A modification, the predominant RNA modification in eukaryotes, adds a novel layer of regulation to the gene expression. Dynamic and reversible m6A modification implements sophisticated and crucial functions in RNA metabolism, including generation, splicing, stability, and translation in messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs). Furthermore, m6A modification plays a determining role in producing various m6A-labeling RNA outcomes, thereby affecting several functional processes, including tumorigenesis and progression. Herein, we highlighted current advances in m6A modification and the regulatory mechanisms underlying mRNAs and ncRNAs in distinct cancer stages. Meanwhile, we also focused on the therapeutic significance of m6A regulators in clinical cancer treatment.

Current advances and future perspectives on the functional roles and clinical implications of circular RNAs in esophageal squamous cell carcinoma: more influential than expected.

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive gastrointestinal cancers with high incidence and mortality. Therefore, it is necessary to identify novel sensitive and specific biomarkers for ESCC detection and treatment. Circular RNAs (circRNAs) are a type of noncoding RNAs featured by their covalently closed circular structure. This special structure makes circRNAs more stable in mammalian cells, coupled with their great abundance and tissue specificity, suggesting circRNAs may present enormous potential to be explored as valuable prognostic and diagnostic biomarkers for tumor. Mounting studies verified the critical roles of circRNAs in regulating ESCC cells malignant behaviors. Here, we summarized the current progresses in a handful of aberrantly expressed circRNAs, and elucidated their biological function and clinical significance in ESCC, and introduced a series of databases for circRNA research. With the improved advancement in high-throughput sequencing and bioinformatics technique, new frontiers of circRNAs will pave the path for the development of precision treatment in ESCC.

Long non-coding RNA BBOX1-AS1 exacerbates esophageal squamous cell carcinoma development by regulating HOXB7/ß-catenin axis.

Mounting evidence suggests that long non-coding RNAs play a critical role in the occurrence and development of human malignancies. Nonetheless, it remains unknown whether Gamma-Butyrobetaine Hydroxylase 1-Antisense RNA 1 (BBOX1-AS1) participates in the regulation of esophageal squamous cell carcinoma (ESCC) carcinogenesis. Herein, we validated that BBOX1-AS1 was notably overexpressed in ESCC tissues compared to the adjacent non-tumor tissues and significantly correlated with tumor sizes. BBOX1-AS1 enhanced the malignant behavior of ESCC cells in vitro, such as cell proliferation, migration, and invasion. In addition, knockdown of BBOX1-AS1 augmented the proportion of apoptotic cells in ESCC cells. Mechanistically, BBOX1-AS1 regulated HOXB7 expression, and rescue experiments indicated that silencing of HOXB7 could abolish the malignant phenotypes mediated by BBOX1-AS1 to a certain extent. Moreover, HOXB7 participated in the activation of the Wnt/ß-catenin signaling pathway. In summary, our findings substantiated that BBOX1-AS1 could activate the Wnt/ß-catenin pathway by upregulating HOXB7 expression to promote ESCC progression, providing a rationale to develop novel therapeutic approaches.

METTL3 restrains papillary thyroid cancer progression via m6A/c-Rel/IL-8-mediated neutrophil infiltration.

Growing evidence indicates that N6-methyladenosine (m6A) is the most pervasive RNA modification in eukaryotic cells. However, the specific role of METTL3 in papillary thyroid carcinoma (PTC) initiation and development remains elusive. Here we found that downregulation of METTL3 was correlated with malignant progression and poor prognosis in PTC. A variety of gain- and loss-of-function studies clarified the effect of METTL3 on regulation of growth and metastasis of PTC cells in vitro and in vivo. By combining RNA sequencing (RNA-seq) and methylated RNA immunoprecipitation sequencing (meRIP-seq), our mechanistic studies pinpointed c-Rel and RelA as downstream m6A targets of METTL3. Disruption of METTL3 elicited secretion of interleukin-8 (IL-8), and elevated concentrations of IL-8 promoted recruitment of tumor-associated neutrophils (TANs) in chemotaxis assays and mouse models. Administration of the IL-8 antagonist SB225002 substantially retarded tumor growth and abolished TAN accumulation in immunodeficient mice. Our findings revealed that METTL3 played a pivotal tumor-suppressor role in PTC carcinogenesis through c-Rel and RelA inactivation of the nuclear factor κB (NF-κB) pathway by cooperating with YTHDF2 and altered TAN infiltration to regulate tumor growth, which extends our understanding of the relationship between m6A modification and plasticity of the tumor microenvironment.

Aberrant SLC6A14 Expression Promotes Proliferation and Metastasis of Colorectal Cancer via Enhancing the JAK2/STAT3 Pathway.

BACKGROUND: Solute carrier family 6 member 14 (SLC6A14) is a high-capacity amino acid transporter in mammalian cells. It has gained increasing attention for its potential involvement in the progression and metabolic reprogramming of various malignant tumors. However, the role of SLC6A14 in colorectal cancer (CRC) remains unclear. METHODS: Real-time polymerase chain reaction (qRT-PCR), immunoblotting and immunohistochemistry were carried out to detect the expression level of SLC6A14 in human CRC tissues and CRC-derived cell lines. HCT-116 and Caco-2 cell lines were selected to conduct in vitro functional studies. Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, cell migration and invasion assays were performed to investigate the role of SLC6A14 in CRC cells. Besides, azoxymethane/dextran sulfate sodium salt (AOM/DSS)-induced CRC and tumor xenograft models were constructed to explore the effects of SLC6A14 blockade or overexpression during tumor progression in vivo. RESULTS: SLC6A14 was substantially increased in human CRC samples and higher levels of SLC6A14 was correlated with advanced tumor stage, lymph node metastasis and dismal survival of CRC patients. SLC6A14 markedly promoted cell growth, inhibited cell apoptosis, and exacerbated migration and invasion of CRC cells in vitro. Mechanistically, SLC6A14 aggravated these malignant phenotypes through activating JAK2/STAT3 signaling pathway, and inhibiting JAK2/STAT3 signaling with specific inhibitors could reverse SLC6A14-mediated tumorigenic effects. Besides, two different animal studies verified the tumor-promoting effect of SLC6A14 in CRC. CONCLUSION: Our data illustrated the crucial function of SLC6A14 during CRC progression, suggesting SLC6A14/JAK2/STAT3 axis may serve as novel therapeutic targets for patients with CRC.

LncRNA FAM83A-AS1 promotes ESCC progression by regulating miR-214/CDC25B axis.

Background: Recent researches have pinpointed that long non-coding RNA (lncRNA) was tightly related to the carcinogenesis. However, the function of lncRNA in esophageal cell squamous carcinoma (ESCC) remains to be explored. In the current study, we assessed the expression pattern and the biological function of FAM83A-AS1 in ESCC. Methods: qRT-PCR was used to detect the expression of FAM83A-AS1, miR-214, and CDC25B expression in ESCC tissues and cell lines. CCK-8, transwell, apoptosis and cell cycle assays were performed to define the function of FAM83A-AS1 in ESCC cells. Furthermore, the regulation of miR-214 by FAM83A-AS1 was defined by qRT- PCR and rescue assays. In addition, the association between CDC25B, miR-214, CDC25B was confirmed by qRT-PCR. Results: Here, we discovered that FAM83A-AS1 was strongly expressed in ESCC tissues. FAM83A-AS1 abundance was associated with TNM stages and the differentiation grade of ESCC patients. The receiver operating characteristic curve (ROC) analysis indicated the high accuracy of FAM83A-AS1 in ESCC diagnosis. Functionally, inhibiting FAM83A-AS1 repressed cell proliferation, migration, and invasion in ESCC. In addition, we found that FAM83A-AS1 accelerated the cell cycle while inhibited cell apoptosis. Mechanistically, we found that FAM83A-AS1 regulated miR-214 expression, and there was a negative correlation between miR-214 and FAM83A-AS1 in ESCC. Rescue assay indicated that miR-214 could impair the suppressing effect of cell migration induced by FAM83A-AS1 depletion. Furthermore, CDC25B was a direct target of miR-214, and FAM83A-AS1 enhanced CDC25B expression while miR-214 positively CDC25B expression in ESCC. Conclusions: Collectively, we concluded that FAM83A-AS1 facilitated ESCC progression by regulating the miR-214/CDC25B axis. Our study showed FAM83A-AS1 may act as a promising target for ESCC diagnosis and therapy.

LncRNA LOXL1-AS1 promotes esophageal squamous cell carcinoma progression by targeting DESC1.

Recently, ample evidence indicated that numerous aberrantly expressed long non-coding RNAs (lncRNAs) participated in the development of multiple malignancies. However, the expression and function of lncRNA LOXL1-AS1 in mediating esophageal squamous cell carcinoma (ESCC) carcinogenesis remains largely elusive. Here we validated that LOXL1-AS1 was significantly upregulated in ESCC tissues compared with the corresponding adjacent non-neoplastic tissues, and LOXL1-AS1 expression was positively correlated with ESCC patients' lymph node metastasis. Besides, LOXL1-AS1 knockdown impaired ESCC cells proliferation, migration and invasion capabilities in vitro. Furthermore, inhibiting LOXL1-AS1 in ESCC cells increased the percentage of cells at the G1 phase, accompanied by reducing in S phase in contrast to scramble control, and silencing of LOXL1-AS1 evoked ESCC cell apoptosis. From high throughput RNA sequencing (RNA-seq) analysis, we identified that differentially expressed in squamous cell carcinoma 1 (DESC1) was a critical downstream target of LOXL1-AS1. Taken together, we demonstrated the function and mechanism of LOXL1-AS1 in contributing ESCC progression for the first time, and indicated LOXL1-AS1 may be a novel therapeutic biomarker of ESCC.

Protective and anti-inflammatory role of REG1A in inflammatory bowel disease induced by JAK/STAT3 signaling axis.

Regenerating islet-derived protein 1-alpha (REG1A) was abnormally upregulated in a series of gastrointestinal inflammatory disorders. However, the potential biological function and underlying regulatory mechanisms of the increased REG1A in inflammatory bowel disease (IBD) pathogenesis remain to be fully elucidated. In this study, we uncovered that REG1A was substantially increased in the inflamed colorectal tissues of IBD patients. And the aberrantly expressed REG1A in intestinal epithelial cells (IEC) prominently inhibited inflammatory responses, promoted cell proliferation and suppressed epithelial apoptosis. Mechanically, IL-6 and IL-22 markedly activated REG1A transcription through triggering JAK/STAT3 signaling pathway. In addition, overexpression of REG1A in mice by systematic delivery of REG1A lentivirus remarkably alleviated DSS-induced inflammatory injury and maintained the integrity of intestinal mucosal barrier. Taken together, our data demonstrated that the novel proliferative factor REG1A controlled by IL-6/IL-22-JAK-STAT3 signaling may provide a promising therapeutic target for patients with IBD.

LncRNA MIR205HG Drives Esophageal Squamous Cell Carcinoma Progression by Regulating miR-214/SOX4 Axis.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a common and fatal malignancy, which has posed a great challenge to public health, especially in China. Dysregulation of long non-coding RNAs is involved in the occurrence, development, invasion, and metastasis of multiple cancers including ESCC. However, little is known about the function of MIR205HG in ESCC. METHODS: We used qRT-PCR to detect the expression level of MIR205HG, miR-214, and SOX4 in human ESCC tissues and cell lines. Loss-of-functional assays were performed to test the impact of MIR205HG on cell proliferation, metastasis, and apoptosis process via CCK-8, transwell, and flow cell cytometry assays. Additionally, the downstream molecular mechanism of MIR205HG in ESCC was explored. RESULTS: Here, we found MIR205HG was substantially up-regulated in ESCC, and there was a positive correlation between MIR205HG expression and tumor size and lymphatic metastasis of ESCC patients. Inhibition of MIR205HG attenuated cell proliferation, migration, and invasion. Silencing MIR205HG increased G1 phase cell counts and decreased S phase cell counts, along with increased apoptotic cell populations. Notably, the rescue assays indicated that miR-214 could partly reverse the influence of MIR205HG on ESCC cell migration. We also found that SOX4 was a direct target mRNA of miR-214, and MIR205HG could act as a molecular sponge to regulate SOX4 expression in ESCC. CONCLUSION: Taken together, our findings demonstrate that MIR205HG promotes ESCC progression by regulating the miR-214/SOX4 axis. MIR205HG may be a novel candidate target for ESCC diagnosis and therapy.

LncRNA MNX1-AS1 promotes progression of esophageal squamous cell carcinoma by regulating miR-34a/SIRT1 axis.

BACKGROUND: Long non-coding RNAs (lncRNAs) are powerful factors influencing the tumorigenesis and metastasis of multiple carcinomas. LncRNA MNX1-AS1 plays critical roles in the progression of tumor formation according to recent research, while its roles in esophageal squamous cell carcinoma (ESCC) remains unknown. METHODS: The expression levels of lncRNA MNX1-AS1 were examined in ESCC tissues by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The role of lncRNA MNX1-AS1 was performed by WST-1 proliferation assays, migration and invasion assays. Besides, the molecular mechanism of lncRNA MNX1-AS1 was verified by online bioinformatics, qRT-PCR and rescue assays. RESULTS: MNX1-AS1 was signifcantly upregulated in ESCC tissues. It was conformed that high MNX1-AS1 expression was associated with ESCC lymph node metastasis. Moreover, we found that knockdown of MNX1-AS1 apparently suppressed the cell proliferation, migration, and invasion capacity. Flow cytometry analysis showed MNX1-AS1 regulated ESCC cell cycle and apoptosis progression. Mechanism analysis revealed that miR-34a inhibitor could rescue the influence of inhibiting MNX1-AS1 on ESCC cells migration by serving as competing endogenous RNA (ceRNAs). Furthermore, we found that miR-34a specifically targeted SIRTI. CONCLUSIONS: Taken together, we demonstrated that lncRNA MNX1-AS1/miR-34a/SIRT1 regulatory axis could play an important role in ESCC progression, and MNX1-AS1 may act as a novel potential biomarker for esophageal squamous cell carcinoma.