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Background Gastric cancer (GC) accounts for high mortality. RNA methylation has recently gained interest as markers in specific tumors. This study aimed to uncover the function of the roles of 25 RNA methylation regulators in GC. Methods RNA sequence and clinical data were downloaded from The Cancer Genome Atlas (TCGA) database. "STRING" and R were performed to analyze the correlation among the methylase. COX and LASSO were performed to screen for prognostic associated RNA methylation regulators. A prognostic model was established based on the expression of methylase. RT-PCR and immunohistochemistry detected the expression of methylase in GC cells and tissue. Kaplan-Meier curve and Cox analysis were applied to evaluate the effectiveness of the model. Results The prediction model was established based on the expression of m6A RNA methylation regulators FTO (fat mass and obesity-associated) and RBM15 (RNA binding motif protein 15). Based on the model, GC patients were divided into "high risk" and "low risk" groups to compare the differences in survival. The model was re-evaluated with the clinical data of our center. Conclusion The two-methylase combination model was an independent prognostic factor of GC.

Aim Traditional non-invasive diagnostic markers for gastric cancer (GC) exhibit insufficient sensitivity and specificity. Circulating exosomes are clinically useful non-invasive biomarkers for tumor diagnosis. In addition to their potential role in cancer biology, circulating long non-coding RNAs (lncRNAs) are a new class of promising cancer biomarkers. In the present study, we aimed to identify lncRNAs in circulating exosomes with potential as biomarkers for GC detection. Methods We compared the expression of CEBPA-AS1 between GC cells and gastric epithelial cells. The biological function of exosomal CEBPA-AS1 was determined by cell phenotype experiments and rescue assays. We also compared the expression of CEBPA-AS1 in cancerous tissue from GC patients and corresponding adjacent normal tissues, as well as the expression of CEBPA-AS1 in plasma exosomes of GC patients and healthy controls. Diagnostic accuracy was assessed by the receiver operating characteristic (ROC) curve and area under the curve (AUC). Results CEBPA-AS1 was highly expressed in both GC cells and in exosomes secreted by GC cells. In addition, CEBPA-AS1-containing exosomes secreted by GC cells could promote cell proliferation and inhibit apoptosis, thereby inducing the malignant behavior of GC cells. The level of CEBPA-AS1 was also significantly increased in tissues and plasma exosomes of GC patients. Stability tests showed that most plasma CEBPA-AS1 was encased in exosomes, thus avoiding degradation by RNases. We evaluated the diagnostic accuracy of exosome-derived CEBPA-AS1. The AUC value of CEBPA-AS1 in discriminating GC patients from healthy controls was 0.824, which was higher than the diagnostic accuracy of other traditional tumor biomarkers. Conclusion CEBPA-AS1-containing exosomes secreted from GC cells could promote cell proliferation, inhibit apoptosis, and induce GC progression, indicating that exosomal CEBPA-AS1 is involved in cell-to-cell communication in GC carcinogenesis. Exosomal CEBPA-AS1 is a promising new biomarker for clinical diagnosis of GC.

Background: Electrolyte disturbance and systemic inflammation contributes to poor prognosis of cancer patients. Levels of serum sodium and globulin can reflect electrolyte homeostasis and inflammatory state, respectively, therefore have potential as prognostic factors for cancer patients. In this study, we hypothesized that sodium to globulin ratio (SGR) could have superior accuracy in predicting cancer patient survival, than sodium and globulin alone. We therefore sought to investigate its efficacy in prognosis of patients with advanced gastric cancer (GC) receiving first-line chemotherapy. Methods: A total of 265 patients, with advanced GC, were recruited in this retrospective study from January 2014 to January 2019. We first determined SGR cut-off values using the receiver operating characteristic (ROC) analysis, then analyzed the relationship between pretreatment SGR and clinicopathological features and the effect of chemotherapy. Finally, we evaluated progression-free survival (PFS) and overall survival (OS) rates of the entire and subgroup populations using univariate and multivariate logistic regressions. Results: SGR recorded a cut-off value of 5.54, and had a significantly higher area under the curve (AUC) value (0.619, p = 0.001) than fibrinogen (0.575, p = 0.034) and albumin (0.610, p = 0.002) alone. Organ metastasis, and peritoneal invasion ratios, as well as neutrophil and CA72-4 levels varied significantly between the low-SGR (SGR≤ 5.54) and high SGR (SGR> 5.54) groups (all p < 0.05). Specifically, patients in the low-SGR group exhibited significantly lower disease control rates (83.4%) than those in the high-SGR group (97.2%) (p < 0.001). Results from multivariate analysis indicated that high-SGR was an independent risk factor for PFS (Hazard ratio [HR]: 0.539, p < 0.001) and OS (HR: 0.574, p < 0.001). Moreover, patients in the low-SGR group exhibited significantly worse PFS (134 vs. 221 days, p < 0.001) and OS (311 vs. 420 days, p < 0.001) than those in the high-SGR group. Furthermore, subgroup analysis revealed that SGR was still a powerful prognostic indicator in GC patients with good prognosis or normal biochemical indexes, including no peritoneal infiltration, normal neutrophil counts, and normal serum sodium and globulin levels (all p < 0.001). Conclusions: Overall, our findings indicate that SGR is a novel and promising prognostic factor for GC patients. It has superior accuracy, to sodium and globulin alone, hence it is a powerful tool for evaluating effects of treatment, PFS, and OS in patients with advanced GC, who receive first-line chemotherapy.

Long noncoding RNA NALT1-induced gastric cancer invasion and metastasis via NOTCH signaling pathway

N6-Methyladenosine (m6A) is the most common posttranscriptional modification of RNA and plays critical roles in cancer pathogenesis. However, the biological function of long noncoding RNA (lncRNA) methylation remains unclear. As a demethylase, ALKBH5 (alkylation repair homolog protein 5) is involved in mediating methylation reversal. The purpose of this study was to investigate lncRNA m6A modification and its role in gastric cancer (GC). Bioinformatics predicted interactions of ALKBH5 with lncRNAs. Five methods were employed to assess the function of nuclear paraspeckle assembly transcript 1 (NEAT1), including gene silencing, RT-PCR, separation of nuclear and cytoplasmic fractions, scrape motility assays, and transwell migration assays. Then, m6A RNA immunoprecipitation and immunofluorescence were used to detect methylated NEAT1 in GC cells. Rescue assays were performed to define the relationship between NEAT1 and ALKBH5. NEAT1 is a potential binding lncRNA of ALKBH5. NEAT1 was overexpressed in GC cells and tissue. Additional experiments confirmed that knockdown of NEAT1 significantly repressed invasion and metastasis of GC cells. ALKBH5 affected the m6A level of NEAT1. The binding of ALKBH5 and NEAT1 influences the expression of EZH2 (a subunit of the polycomb repressive complex) and thus affects GC invasion and metastasis. Our findings indicate a novel mechanism by which ALKBH5 promotes GC invasion and metastasis by demethylating the lncRNA NEAT1. They may be potential therapeutic targets for GC.

Our previous study demonstrated that heterogeneous nuclear ribonucleoprotein AB (HNRNPAB) is a key gene that facilitates metastasis of hepatocellular carcinoma (HCC). However, the molecular mechanisms behind this relationship are not fully understood. In our study, we utilized long-noncoding RNA (lncRNA) microarrays to identify a HNRNPAB-regulated lncRNA named lnc-ELF209. Our findings from chromatin immunoprecipitation assays indicate that HNRNPAB represses lnc-ELF209 transcription by directly binding to its promoter region. We also analyzed clinical samples from HCC patients and cell lines with quantitative real-time polymerase chain reactions, RNA in situ hybridization and immunohistochemistry, and found that there is a negative relationship between HNRNPAB and lnc-ELF209 expression. Up/downregulation assays and rescue assays indicate that lnc-ELF209 inhibits cell migration, invasion and epithelial-mesenchymal transition regulated by HNRNPAB. This suggests a new regulatory mechanism for HNRNPAB-promoted HCC progression. RNA pull-down and LC-MS/MS were used to determine triosephosphate isomerase, heat shock protein 90-beta and vimentin may be involved in the tumor-suppressed function of lnc-ELF209. Furthermore, we found lnc-ELF209 could stabilize TPI protein expression. We also found that lnc-ELF209 overexpression in HCCLM3 cell resulted in a lower rate of lung metastatic, which suggested a less aggressive HCC phenotype. Collectively, these findings offer new insights into the regulatory mechanisms that underlie HNRNPAB cancer-promoting activities and demonstrate that lnc-ELF209 is a HNRNPAB-regulated lncRNA that may play an important role in the inhibition of HCC progression.

Background: Disrupted gene levels are intimately correlated with the occurrence and prognosis of gastric cancer (GC). As genes do not function in isolation, we set out to investigate the possible relationship among mRNA and non-coding RNAs (ncRNAs). Materials and methods: RNA sequencing from 406 cases of GC was acquired through the TCGA database. R packages were utilized to assess differential RNA expression. The competing endogenous RNA (ceRNA) network was predicted using miRcode, miRDB, mirTarBase, Target Scan and constructed by Cytoscape 3.6.1. GO enrichment analysis, KEGG pathway analysis, GSEA, and WGCNA were applied for pathway analysis. The expression of select candidate molecules was confirmed using western blot and RT-PCR in GC cells and tissues. CCK-8, EdU staining, and Transwell assays were conducted to assess the influence of candidate molecules on proliferation and invasion. The gain and loss-of-function were achieved by co-culture with sh-lncRNA, mimics and sh-mRNA. Luciferase reporters were created using the psiCHECK2 vector, and the relative luciferase activity was calculated. Results: Using data from TCGA, we determined differentially expressed RNAs and created a ceRNA regulatory network. Interestingly, we identified a regulatory complex surrounding ANGPT2. We detected that ANGPT2 was highly expressed in GC, which correlated with a worse prognosis. Our findings indicated that ANGPT2 encourages growth, invasion, and epithelial-mesenchymal transition (EMT) in GC. Importantly, miR-145 inhibits ANGPT2 and abrogates its effects. Furthermore, LINC00184, a ceRNA, blocks miR-145, thereby improving ANGPT2-mediated carcinogenesis. Conclusions: Our findings indicate that the LINC00184/miR-145/ANGPT2 pathway has a crucial function in the development of GC and can act as a possible biomarker and targets for GC therapy.

Background Gastric cancer (GC) is one of the most frequently diagnosed gastrointestinal cancers throughout the world. Novel prognostic biomarkers are required to predict the prognosis of GC. Aim To identify a multi-long noncoding RNA (lncRNA) prognostic model for GC. Methods Transcriptome data and clinical data were downloaded from The Cancer Genome Atlas. COX and least absolute shrinkage and selection operator regression analyses were performed to screen for prognosis associated lncRNAs. Receiver operating characteristic curve and Kaplan-Meier survival analyses were applied to evaluate the effectiveness of the model. Results The prediction model was established based on the expression of AC007991.4, AC079385.3, and AL109615.2 Based on the model, GC patients were divided into "high risk" and "low risk" groups to compare the differences in survival. The model was re-evaluated with the clinical data of our center. Conclusion The 3-lncRNA combination model is an independent prognostic factor for GC.

Clinically, hypoxia is associated with increased distant metastasis and poor survival in gastric cancer (GC). In this study, we set out from the cellular interaction to further explain the molecular mechanism of invasion in GC cells under hypoxic conditions. Gastric cancer cells were cultured under 1% O2 (hypoxia-cultured gastric cancer cells, HGC) and 20% O2 condition (normoxic-cultured gastric cancer cells, NGC). NGC was co-cultured with HGC-medium. Scrape and Transwell were used to evaluate invasion and migration. Exosomes from GC were extracted by ultracentrifugation. Electron microscopy images, western-blot used to analyze the size distributions and the number of exosomes. HGC-medium induced NGC dissociated. Long non-coding RNA (lncRNA) prostate cancer gene expression marker 1 (PCGEM1) was specifically expressed in HGC exosomes. HGC-derived PCGEM1-riched exosomes could promote the invasion and migration of NGC. On the mechanism, PCGEM1 maintained stability and reduced the degradation of SNAI1, which could induce the epithelial–mesenchymal transition of GC. LncRNA PCGEM1 was overexpressed in GC cells. And part of the PCGEM1 can be encapsulated into exosomes. These exosomes promoted invasion and migration of other GC cells. We considered PCGEM1 might act as a "scaffold" combined with SNAI1 and prompt the invasion and migration of GC.

The fibrinogen-to-albumin ratio (FAR), reflecting the systemic coagulation, nutritional and inflammation status of patients, has matured into a prognostic marker for several tumor types. However, only a few studies have assessed the utility of the FAR as a prognostic indicator in patients with advanced gastric cancer (GC) receiving first-line chemotherapy. In the present study, 273 patients with advanced GC who received first-line chemotherapy between January 2014 and January 2019 at the Cancer Hospital of China Medical University (Shenyang, China) were retrospectively analyzed. Using the cut-off values determined by receiver operating characteristic (ROC) analysis, the patients were divided into low-FAR (≤10.03) and high-FAR (>10.03), low-fibrinogen (

Gastric cancer (GC) is the fifth most common cancer and the third leading cause of cancer-related mortality worldwide. Inflammation and the nutritional status of patients with GC are important factors affecting the therapeutic effect and prognosis. Inflammatory and nutrition-related markers have been shown to be prognostic factors for patients with GC. However, few studies have investigated the relationship of the prealbumin-to-globulin ratio (PGR) with the prognosis of GC patients. The objective of the present study was to examine whether pretreatment PGR is related to the prognosis and chemotherapy outcomes of in-patients with advanced GC undergoing first-line chemotherapy. We retrospectively reviewed the data of 281 patients with unresectable GC from January 2013 to January 2018. The receiver operating characteristic curve analysis determined the cut-off values for the PGR. The relationship between the PGR and chemotherapy effectiveness was evaluated using the chi-square test. Kaplan-Meier’s method was used to plot progression-free survival (PFS) and overall survival (OS) curves, using multivariable Cox regression analysis to identify promising predictors of mortality. The cut-off value for the PGR was 7.21. The high-PGR (≥7.21) group had a higher disease control rate than that of the low-PGR group (93.66% vs. 78.42%, p<0.001). Kaplan-Meier’s analysis showed significantly higher median PFS (189 vs. 125 days, p<0.001) and OS (350 vs. 288 days, p<0.001) in the high-PGR group. The multivariate analyses revealed that a high PGR is an independent protective factor in patients with advanced GC, both in terms of PFS (hazard ratio [HR]: 0.672; 95% confidence interval [CI]: 0.527–0.857; p<0.001) and OS (HR: 0.675; 95% CI: 0.530–0.861; p=0.002). In conclusion, the prechemotherapy PGR can accurately predict the chemotherapy outcome, PFS, and OS of patients with advanced GC. Therefore, medical practitioners can utilize the PGR as a novel dependable prognostic tool to weigh the prognosis of patients with GC.

Background Increasing evidence supports the role of small nucleolar RNAs (snoRNAs) and long non-coding RNAs (lncRNAs) as master gene regulators at the epigenetic modification level. However, the underlying mechanism of these functional ncRNAs in colorectal cancer (CRC) has not been well investigated. Methods The dysregulated expression profiling of lncRNAs-snoRNAs-mRNAs and their correlations and co-expression enrichment were assessed by GeneChip microarray analysis. The candidate lncRNAs, snoRNAs, and target genes were detected by in situ hybridization (ISH), RT-PCR, qPCR and immunofluorescence (IF) assays. The biological functions of these factors were investigated using in vitro and in vivo studies that included CCK8, trans-well, cell apoptosis, IF assay, western blot method, and the xenograft mice models. rRNA 2′-O-methylation (Me) activities were determined by the RTL-P assay and a novel double-stranded primer based on the single-stranded toehold (DPBST) assay. The underlying molecular mechanisms were explored by bioinformatics and RNA stability, RNA fluorescence ISH, RNA pull-down and translation inhibition assays. Results To demonstrate the involvement of lncRNA and snoRNAs in 2′-O-Me modification during tumorigenesis, we uncovered a previously unreported mechanism linking the snoRNPs NOP58 regulated by ZFAS1 in control of SNORD12C, SNORD78 mediated rRNA 2′-O-Me activities in CRC initiation and development. Specifically, ZFAS1 exerts its oncogenic functions and significantly up-regulated accompanied by elevated NOP58, SNORD12C/78 expression in CRC cells and tissues. ZFAS1 knockdown suppressed CRC cell proliferation, migration, and increased cell apoptosis, and this inhibitory effect could be reversed by NOP58 overexpression in vitro and in vivo. Mechanistically, the NOP58 protein could be recognized by the specific motif (AAGA or CAGA) of ZFAS1. This event accelerates the assembly of SNORD12C/78 to allow for further guiding of 2′-O-Me at the corresponding Gm3878 and Gm4593 sites. Importantly, silencing SNORD12C or 78 reduced the rRNAs 2′-O-Me activities, which could be rescued by overexpression ZFAS1, and this subsequently inhibits the RNA stability and translation activity of their downstream targets (e.g., EIF4A3 and LAMC2). Conclusion The novel ZFAS1-NOP58-SNORD12C/78-EIF4A3/LAMC2 signaling axis that functions in CRC tumorigenesis provides a better understanding regarding the role of lncRNA-snoRNP-mediated rRNAs 2′-O-Me activities for the prevention and treatment of CRC.

Gastric cancer (GC) is the most common and aggressive cancer of the digestive system and poses a serious threat to human health. Since genes do not work alone, our aim was to elucidate the potential network of mRNAs and noncoding RNAs (ncRNAs) in this study. Transcriptome data of GC were obtained from TCGA. R and Perl were used to obtain the differentially expressed RNAs and construct a competing endogenous RNA (ceRNA) regulatory network. To investigate the biological functions of differentially expressed RNAs, loss-of-function and gain-of-function experiments were performed. Real-time PCR (RT-qPCR), western blot analysis, dual-luciferase reporter assays and fluorescence in situ hybridization were conducted to explore the underlying mechanisms of competitive endogenous RNAs (ceRNAs). Based on TCGA data and bioinformatics analysis, we identified the LINC00163/miR-183/A-Kinase Anchoring Protein 12 (AKAP12) axis. We observed that AKAP12 was weakly expressed in GC and suppressed invasion and metastasis in GC cells, which could be abolished by miR-183. In addition, LINC00163 can be used as a ceRNA to inhibit the expression of miR-183, thus enhancing the anticancer effect of AKAP12. Our results demonstrated that weak LINC00163 expression in GC can sponge miR-183 to promote AKAP12. We established that the LINC00163/miR-183/AKAP12 axis plays an important role in GC invasion and metastasis and may be a potential biomarker and target for GC treatment.

Objectives The purpose of this study was to explore whether pretreatment potential prognostic factors are related to chemotherapeutic outcomes and the prognosis of inpatients with metastatic colorectal cancer (mCRC) undergoing chemotherapy. Materials and methods Data from 71 patients with mCRC were analyzed retrospectively. The relationship between the potential prognostic factors before first‐line chemotherapy and the clinicopathological characteristics and chemotherapy response of the patients was calculated using Fisher's exact test and the chi‐square test. The prognostic factors were analyzed using univariate and multivariate analyses. We analyzed the subgroups using the Mann‐Whitney U test. Results Four factors were eventually used as prognostic factors, namely the albumin‐to‐globulin ratio (AGR), the fibrinogen‐to‐albumin ratio (FAR), the prealbumin‐to‐globulin ratio (PGR), and the fibrinogen‐to‐prealbumin ratio (FPR); the cutoff values of the four potential prognostic factors were 1.40, 10.63, 5.44, and 18.49, respectively. The high AGR and PGR groups had a higher response rate than that of the low groups. Patients in the low FAR and FPR groups showed a higher objective response rate than the high FAR and FPR groups. Patients with low FPR were associated with a higher disease control rate than patients with high FPR. Higher progression‐free survival (PFS) was observed in the high AGR and PGR and low FAR and FPR groups. The AGR, FAR, PGR, and FPR were considered reliable prognostic factors for PFS in a univariate analysis. Conclusions The prechemotherapy AGR, FAR, PGR, and FPR were good prognostic factors to predict the chemotherapy response and PFS in patients with mCRC.

Aim Previous studies have confirmed that overexpression of the long non-coding RNA prostate cancer gene expression marker 1 (PCGEM1) contributes to the invasion and metastasis of gastric cancer (GC) cells. However, the expression of circulating PCGEM1 in the plasma of GC patients and its clinical value remain unclear. Methods A total of 317 patients with GC and 100 healthy subjects were enrolled in this study. Circulating PCGEM1 was detected by reverse transcription-polymerase chain reaction. The diagnostic value of plasma PCGEM1 was evaluated by receiver operating characteristic curves and the area under the curve (AUC) value. Results The expression level of PCGEM1 in the GC group was significantly higher than that in the healthy control subjects. In addition, the PCGEM1 expression level was associated with tumor differentiation and TNM stage. The AUC value of PCGEM1 was higher than that of other conventional tumor markers (CEA, CA12-5, CA72-4, AFP, and CA19-9), although the combination of all markers showed the highest predictive value. Conclusion Plasma PCGEM1 may be a potential novel circulating biomarker for GC diagnosis and prognosis.