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.

Crosstalk of Exosomal Non-Coding RNAs in The Tumor Microenvironment: Novel Frontiers.

The tumor microenvironment (TME) is defined as a complex and dynamic tissue entity composed of endothelial, stromal, immune cells, and the blood system. The homeostasis and evolution of the TME are governed by intimate interactions among cellular compartments. The malignant behavior of cancer cells, such as infiltrating growth, proliferation, invasion, and metastasis, is predominantly dependent on the bidirectional communication between tumor cells and the TME. And such dialogue mainly involves the transfer of multifunctional regulatory molecules from tumor cells and/or stromal cells within the TME. Interestingly, increasing evidence has confirmed that exosomes carrying regulatory molecules, proteins, and nucleic acids act as an active link in cellular crosstalk in the TME. Notably, extensive studies have identified non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), that could be encapsulated by exosomes, which regulate the coordinated function within the TME and thus participate in cancer development and progression. In this review, we summarize recent literature around the topic of the functions and mechanisms of exosomal ncRNAs in the TME and highlight their clinical significance.

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 MIR31HG functions as a ceRNA to regulate c-Met function by sponging miR-34a in esophageal squamous cell carcinoma.

Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) function as essential regulators in the development and progression of multiple tumors. However, the molecular mechanisms of MIR31HG in regulating ESCC progression remain unknown. Here, we confirmed that MIR31HG facilitated ESCC cells proliferation in vivo. Besides, MIR31HG knockdown increases the percentage of cells at the G1 phase, along with reduced arrest in S phase and MIR31HG overexpression exhibits the opposite effects. Overexpressed MIR31HG decreases the percentage of apoptotic ESCC cells. Interestingly, MIR31HG can function as a competing endogenous RNA by sponging miR-34a. The rescue experiments demonstrated that MIR31HG function is partially reversed by inhibiting miR-34a. In addition, we found c-Met is a target gene of miR-34a and is indirectly regulated by MIR31HG. Taken together, our findings revealed that MIR31HG promotes ESCC progression by regulating miR-34a/ c-Met axis and may provide a new prospective for exploration and understanding of the biological effects of esophageal squamous cell carcinoma.

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.

Long noncoding RNA FEZF1-AS1 promotes the motility of esophageal squamous cell carcinoma through Wnt/ß-catenin pathway.

Background: Long noncoding RNAs (lncRNAs), a class of noncoding RNA nucleotides >200 bp, has been demonstrated to play vital role in the development of cancer. FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1) has been reported as an lncRNA which acts as a tumor-promoting effect in some cancers. However, the role of it in esophageal squamous cell carcinoma (ESCC) and its potential regulatory mechanism was unclear now. Methods: qRT-PCR was used to detect the levels of FEZF1-AS1 and mRNA CTNNB1 (ß-catenin) in ESCC tissues and cells. Cell transfection experiments were used to knock down or overexpress the level of FEZF1-AS1 in EC1 and EC9706 cell lines. WST-1 assays, cell cycle assays, scratch wound assays, migration, and invasion assays were used to evaluate the function of FEZF1-AS1 in ESCC progression. Results: FEZF1-AS1 was remarkably upregulated in ESCC tissues and cell lines. Silencing of FEZF1-AS1 significantly inhibited the migration and invasion of ESCC cells, while overexpression of FEZF1-AS1 notably accelerated ESCC migration and invasion. Meanwhile, the levels of FEZF1-AS1 had no effect on ESCC cell proliferation and cell cycle. We also found that ß-catenin was upregulated in ESCC tissues, and the level of it was positively correlated with the expression of FEZF1-AS1. Silencing of FEZF1-AS1 could decrease the mRNA and protein level of ß-catenin, while overexpression FEZF1-AS1 could lead to the contrary. Conclusion: Our results suggested that the expression of lncRNA FEZF1-AS1 played an important role in ESCC progression, especially the motility of the tumor. FEZF1-AS1 may provide us with a new sight for ESCC treatment.

Efficacy of combined orthodontic-periodontic treatment for patients with periodontitis and its effect on inflammatory cytokines: A comparative study.

INTRODUCTION: In this study, we aimed to investigate the efficacy of combined orthodontic-periodontic treatment in the treatment of patients with periodontitis and its effects on the levels of inflammatory cytokines. METHODS: A total of 117 patients with periodontitis were randomly assigned to the basic group (receiving basic periodontic treatment, n = 58) and the combined group (receiving combined orthodontic-periodontic treatment, n = 59). In addition, 52 healthy people without periodontal disease were selected as the normal group. Probing depth, tooth mobility, plaque index, clinical attachment level, and sulcus bleeding index were recorded. ELISA was applied to detect gingival crevicular fluid (GCF) and serum levels of inflammatory cytokines. A 2-year clinical follow-up was conducted. RESULTS: Before treatment, the periodontal parameters (probing depth, tooth mobility, plaque index, clinical attachement level, and sulcus bleeding index) and GCF and serum levels of inflammatory cytokines (high-sensitivity C-reactive protein, interleukin-1ß, interleukin-5, interleukin-6, interleukin-8, tumor necrosis factor-α, and prostaglandin E2) in the combined and basic groups were higher than those in the normal group. After 6 and 18 months of treatment, the periodontal parameters and GCF and serum levels of inflammatory cytokines decreased in the combined and basic groups. The periodontal parameters and the GCF and serum levels of inflammatory cytokines in the combined group were significantly lower than those in the basic group after 18 months of treatment. The combined group had a lower recurrence rate compared with the basic group. CONCLUSIONS: Combined orthodontic-periodontic treatment had good clinical efficacy in the treatment of periodontitis and could effectively decrease the levels of inflammatory cytokines.

Association of CYP1A1 and GSTM1 Polymorphisms With Oral Cancer Susceptibility: A Meta-Analysis.

Our meta-analysis was aimed to evaluate the association of CYP1A1 and glutathione-S-transferase M1 (GSTM1) polymorphisms with oral cancer susceptibility.The related articles were searched in PubMed, Embase, and CNKI databases. Fifty eligible studies were included in our meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the relationship of CYP1A1 (rs4646903 and rs1048943) and GSTM1 polymorphisms with oral cancer risk. A random-effects model or fixed-effects model was employed depending on the heterogeneity.In overall analysis, CYP1A1 rs4646903 polymorphism was associated with the risk of oral cancer (CC vs TT: OR 1.65, 95% CI 1.33-2.05; CC vs TC+TT: OR 1.77, 95% CI 1.48-2.11; C vs T: OR 1.17, 95% CI 1.07-1.28), whereas rs1048943 showed no obvious association with oral cancer susceptibility. Moreover, subgroup analysis by ethnicity demonstrated that rs4646903 and rs1048943 both related with increased risk of oral cancer in Asians. Moreover, the analysis based on source of control suggested that rs4646903 could increase the risk for oral cancer in both population- and hospital-based populations, whereas no remarkable relationship of rs1048943 with oral cancer susceptibility was observed. For GSTM1 gene, null genotype appeared to be a risk factor for oral cancer (null vs present: OR 1.23, 95% CI 1.12-1.34), which was also proved in the subgroup analysis.The results demonstrated that CYP1A1 rs4646903 and null genotype of GSTM1 polymorphisms might serve as risk factors for oral cancer.