Long Non-Coding RNA LOC339059 Attenuates IL-6/STAT3-Signaling-Mediated PDL1 Expression and Macrophage M2 Polarization by Interacting with c-Myc in Gastric Cancer.

Background: Long non-coding RNA (lncRNA) was identified as a novel diagnostic biomarker in gastric cancer (GC). However, the functions of lncRNAs in immuno-microenvironments have not been comprehensively explored. In this study, we explored a critical lncRNA, LOC339059, that can predict the clinical prognosis in GC related to the modulation of PD-L1 and determined its influence upon macrophage polarization via the IL-6/STAT3 pathway. Methods: To date, accumulating evidence has demonstrated that the dysregulation of LOC339059 plays an important role in the pathological processes of GC. It acts as a tumor suppressor, regulating GC cell proliferation, migration, invasion, tumorigenesis, and metastasis. A flow cytometry assay showed that the loss of LOC339059 enhanced PDL1 expression and M2 macrophage polarization. RNA sequencing, RNA pull-down, RNA immunoprecipitation, Chip-PCR, and a luciferase reporter assay revealed the pivotal role of signaling alternation between LOC339059 and c-Myc. Results: A lower level of LOC339059 RNA was found in primary GC tissues compared to adjacent tissues, and such a lower level is associated with a poorer survival period (2.5 years) after surgery in patient cohorts. Moreover, we determined important immunological molecular biomarkers. We found that LOC339059 expression was correlated with PD-L1, CTLA4, CD206, and CD204, but not with TIM3, FOXP3, CD3, C33, CD64, or CD80, in a total of 146 GC RNA samples. The gain of LOC339059 in SGC7901 and AGS inhibited biological characteristics of malignancy, such as proliferation, migration, invasion, tumorigenesis, and metastasis. Furthermore, our data gathered following the co-culture of THP-1 and U937 with genomic GC cells indicate that LOC339059 led to a reduction in the macrophage cell ratio, in terms of CD68+/CD206+, to 1/6, whereas the selective knockdown of LOC339059 promoted the abovementioned malignant cell phenotypes, suggesting that it has a tumor-suppressing role in GC. RNA-Seq analyses showed that the gain of LOC339059 repressed the expression of the interleukin family, especially IL-6/STAT3 signaling. The rescue of IL-6 in LOC339059-overexpressing cells reverted the inhibitory effects of the gain of LOC339059 on malignant cell phenotypes. Our experiments verified that the interaction between LOC339059 and c-Myc resulted in less c-Myc binding to the IL-6 promoter, leading to the inactivation of IL-6 transcription. Conclusions: Our results establish that LOC339059 acts as a tumor suppressor in GC by competitively inhibiting c-Myc, resulting in diminished IL-6/STAT3-signaling-mediated PDL1 expression and macrophage M2 polarization.

Long non-coding RNA SNHG1 suppresses cell migration and invasion and upregulates SOCS2 in human gastric carcinoma.

Gastric carcinoma (GC) is one of the most common malignancies and the third leading cause of cancer-related deaths worldwide. Long noncoding RNAs (lncRNAs) may be an important class of functional regulators involved in human gastric cancers development. In this study, we investigated the clinical significance and function of lncRNA SNHG1 in GC. SNHG1 was significantly downregulated in GC tumor tissues compared with adjacent noncancerous tissues. Overexpression of SNHG1 in BGC-823 cells remarkably inhibited not only cell proliferation, migration, invasion in vitro, but also tumorigenesis and lung metastasis in the chick embryo chorioallantoic membrane (CAM) assay in vivo. Conversely, inhibition of SNHG1 by transfection of siRNA in AGS cells resulted in opposite phenotype changes. Mechanically, SNHG1 was found interacted with ILF3, NONO and SFPQ. RNA-seq combined with bioinformatic analysis identified a serial of downstream genes of SNHG1, including SOCS2, LOXL2, LTBP3, LTBP4. Overexpression of SNHG1 induced SOCS2 expression whereas knockdown of SNHG1 decreased SOCS2 expression. In addition, knockdown of SNHG1 promoted the activation of JAK2/STAT signaling pathway. Taken together, our data suggested that SNHG1 suppressed aggressive phenotype of GC cells and regulated SOCS2/JAK2/STAT pathway.

The T-Cell-Inflammation Status Can Predict Outcomes of Adjuvant Chemotherapy in Patients with Gastric Cancer.

BACKGROUND: Immunogenic chemotherapy promotes antitumor immune response in the tumor microenvironment (TME). In gastric cancer, the effect of a preexisting T-cell-inflamed TME on the efficacy of adjuvant chemotherapy (ACT) is unclear. The purpose of the present study was to evaluate the benefits of ACT in T-cell-inflamed gastric cancer. METHODS: Three cohorts (n = 267, 300, and 198) of gastric cancer patients who underwent gastrectomy with or without ACT were included in this study. Based on a well-defined T-cell-inflamed gene signature, which includes 13 genes, these patients were classified into non-T-cell-inflamed, intermediate T-cell-inflamed, and T-cell-inflamed subgroups. The CIBERSORT software was used to estimate the immune cells infiltrating the TME, and the Kaplan-Meier curve was plotted for survival analysis. RESULTS: The T-cell-inflamed patients had high levels of CD8 + T, gamma delta T, and activated CD4 + memory T cells, whereas low level of resting NK cells was observed in all the three cohorts (all P < 0.05). In patients with stage II-IV disease without distant metastasis, those who were T-cell-inflamed were more likely to benefit from ACT (all P < 0.05), regardless of the chemotherapy regimen. Furthermore, patients with both T-cell-inflamed and high microsatellite instability status also were likely to benefit from ACT (P = 0.019). CONCLUSIONS: The present study shows that T-cell inflammation is predictive of a survival benefit from ACT. Our findings will be helpful in making decisions regarding the use of chemotherapy in combination with immunotherapy to improve the clinical outcomes in patients with gastric cancer.

BTEB2-Activated lncRNA TSPEAR-AS2 Drives GC Progression through Suppressing GJA1 Expression and Upregulating CLDN4 Expression.

Long non-coding RNAs (lncRNAs) are characterized as key layers of the genome in various cancers. TSPEAR-AS2 was highlighted to be a candidate lncRNA potentially involved in gastric cancer (GC) progression. However, the clinical significance and mechanism of TSPEAR-AS2 in GC required clarification. The clinical significance of TSPEAR-AS2 was elucidated through Kaplan-Meier Plotter. The mechanism of TSPEAR-AS2 in GC was clarified in vitro and in vivo using luciferase reporter, chromatin immunoprecipitation, RNA immunoprecipitation assays, and animal models. TSPEAR-AS2 elevation was closely correlated with overall survival of GC patients. A basic transcription element-binding protein 2 (BTEB2)-activated TSPEAR-AS2 model was first explored in this study. TSPEAR-AS2 silencing substantially reduced tumorigenic capacities of GC cells, while TSPEAR-AS2 elevation had the opposite effect. Mechanistically, TSPEAR-AS2 bound with both polycomb repressive complex 2 (PRC2) and argonaute 2 (Ago2). TSPEAR-AS2 knockdown significantly decreased H3K27me3 levels at promoter regions of gap junction protein alpha 1 (GJA1). Ago2 was recruited by TSPEAR-AS2, which was defined to sponge miR-1207-5p, contributing to the repression of claudin 4 (CLDN4) translation. The axis of EZH2/GJA1 and miR-1207-5p/CLDN4 mediated by BTEB2-activated-TSPEAR-AS2 plays an important role in GC progression, suggesting a new therapeutic direction in GC treatment.

TNFRSF11B activates Wnt/ß-catenin signaling and promotes gastric cancer progression.

Tumor necrosis factor receptor superfamily member 11B (TNFRSF11B) has been studied to be involved in the development and progression of several human malignancies. However, little is unveiled regarding the complex mechanisms of TNFRSF11B in human gastric cancer (GC). The clinical significance of TNFRSF11B was assessed in 70 and 160 GC tissues using immunohistochemistry method and gene microarray analysis, respectively. The biological function of TNFRSF11B was studied in vitro and in vivo assays. Immunofluorescence assay was used to evaluate the expression of ß-catenin in the nucleus. The expression of ß-catenin and related protein was determined by Western blot. The interaction between TNFRSF11B and GSK3ß was detected by co-immunoprecipitation. We demonstrated that TNFRSF11B was highly expressed in the cytoplasm of GC and associated with the patient poor outcome. Our studies showed that TNFRSF11B in GC cells significantly promoted cell proliferation, migration, invasion in vitro and tumorigenic ability in vitro and in vivo. Meanwhile, TNFRSF11B inhibited GC cell apoptosis. The proportion of nuclear active ß-catenin showed positively correlation with TNFRSF11B expression. TNFRSF11B directly combined with GSK-3ß upregulating its phosphorylation, and increased expression of ß-catenin and its downstream effectors. Collectively, these findings demonstrate that TNFRSF11B promote the aggressive phenotypes of GC cells and activated Wnt/ß-catenin signaling. Accordingly, TNFRSF11B had potential as a biomarker and inhibition of TNFRSF11B expression might offer a new therapeutic target for GC patients.

Multi-omics characterization of molecular features of gastric cancer correlated with response to neoadjuvant chemotherapy.

Neoadjuvant chemotherapy is a common treatment for patients with gastric cancer. Although its benefits have been demonstrated, neoadjuvant chemotherapy is underutilized in gastric cancer management, because of the lack of biomarkers for patient selection and a limited understanding of resistance mechanisms. Here, we performed whole-genome, whole-exome, and RNA sequencing on 84 clinical samples (including matched pre- and posttreatment tumors) from 35 patients whose responses to neoadjuvant chemotherapy were rigorously defined. We observed increased microsatellite instability and mutation burden in nonresponse tumors. Through comparisons of response versus nonresponse tumors and pre- versus posttreatment samples, we found that C10orf71 mutations were associated with treatment resistance, which was supported by drug response data and potentially through inhibition of cell cycle, and that MYC amplification correlated with treatment sensitivity, whereas MDM2 amplification showed the opposite pattern. Neoadjuvant chemotherapy also reshapes tumor-immune signaling and microenvironment. Our study provides a critical basis for developing precision neoadjuvant regimens.

TfR1 binding with H-ferritin nanocarrier achieves prognostic diagnosis and enhances the therapeutic efficacy in clinical gastric cancer.

H-ferritin (HFn) nanocarrier is emerging as a promising theranostic platform for tumor diagnosis and therapy, which can specifically target tumor cells via binding transferrin receptor 1 (TfR1). This led us to investigate the therapeutic function of TfR1 in GC. The clinical significance of TfR1 was assessed in 178 GC tissues by using a magneto-HFn nanoparticle-based immunohistochemistry method. The therapeutic effects of doxorubicin-loaded HFn nanocarriers (HFn-Dox) were evaluated on TfR1-positive GC patient-derived xenograft (GC-PDX) models. The biological function of TfR1 was investigated through in vitro and in vivo assays. TfR1 was upregulated (73.03%) in GC tissues, and reversely correlated with patient outcome. TfR1-negative sorted cells exhibited tumor-initiating features, which enhanced tumor formation and migration/invasion, whereas TfR1-positive sorted cells showed significant proliferation ability. Knockout of TfR1 in GC cells also enhanced cell invasion. TfR1-deficient cells displayed immune escape by upregulating PD-L1, CXCL9, and CXCL10, when disposed with IFN-γ. Western blot results demonstrated that TfR1-knockout GC cells upregulated Akt and STAT3 signaling. Moreover, in TfR1-positive GC-PDX models, the HFn-Dox group significantly inhibited tumor growth, and increased mouse survival, compared with that of free-Dox group. TfR1 could be a potential prognostic and therapeutic biomarker for GC: (i) TfR1 reversely correlated with patient outcome, and its negative cells possessed tumor-aggressive features; (ii) TfR1-positive cells can be killed by HFn drug nanocarrier. Given the heterogeneity of GC, HFn drug nanocarrier combined with other therapies toward TfR1-negative cells (such as small molecules or immunotherapy) will be a new option for GC treatment.

Circular RNAs in the tumour microenvironment.

BACKGROUND: Circular RNAs (circRNAs) are a new class of endogenous non-coding RNAs (ncRNAs) widely expressed in eukaryotic cells. Mounting evidence has highlighted circRNAs as critical regulators of various tumours. More importantly, circRNAs have been revealed to recruit and reprogram key components involved in the tumour microenvironment (TME), and mediate various signaling pathways, thus affecting tumourigenesis, angiogenesis, immune response, and metastatic progression. In this review, we briefly introduce the biogenesis, characteristics and classification of circRNAs, and describe various mechanistic models of circRNAs. Further, we provide the first systematic overview of the interplay between circRNAs and cellular/non-cellular counterparts of the TME and highlight the potential of circRNAs as prospective biomarkers or targets in cancer clinics. Finally, we discuss the biological mechanisms through which the circRNAs drive development of resistance, revealing the mystery of circRNAs in drug resistance of tumours. SHORT CONCLUSION: Deep understanding the emerging role of circRNAs and their involvements in the TME may provide potential biomarkers and therapeutic targets for cancer patients. The combined targeting of circRNAs and co-activated components in the TME may achieve higher therapeutic efficiency and become a new mode of tumour therapy in the future.

Phosphoglucose isomerase gene expression as a prognostic biomarker of gastric cancer.

OBJECTIVE: Tumor heterogeneity renders identification of suitable biomarkers of gastric cancer (GC) challenging. Here, we aimed to identify prognostic genes of GC using computational analysis. METHODS: We first used microarray technology to profile gene expression of GC and paired nontumor tissues from 198 patients. Based on these profiles and patients' clinical information, we next identified prognostic genes using novel computational approaches. Phosphoglucose isomerase, also known as glucose-6-phosphate isomerase (GPI), which ranked first among 27 candidate genes, was further investigated by a new analytical tool namely enviro-geno-pheno-state (E-GPS) analysis. Suitability of GPI as a prognostic marker, and its relationship with physiological processes such as metabolism, epithelial-mesenchymal transition (EMT), as well as drug sensitivity were evaluated using both our own and independent public datasets. RESULTS: We found that higher expression of GPI in GC correlated with prolonged survival of patients. Particularly, a combination of CDH2 and GPI expression effectively stratified the outcomes of patients with TNM stage II/III. Down-regulation of GPI in tumor tissues correlated well with depressed glucose metabolism and fatty acid synthesis, as well as enhanced fatty acid oxidation and creatine metabolism, indicating that GPI represents a suitable marker for increased probability of EMT in GC cells. CONCLUSIONS: Our findings strongly suggest that GPI acts as a novel biomarker candidate for GC prognosis, allowing greatly enhanced clinical management of GC patients. The potential metabolic rewiring correlated with GPI also provides new insights into studying the relationship between cancer metabolism and patient survival.

EIF3B is associated with poor outcomes in gastric cancer patients and promotes cancer progression via the PI3K/AKT/mTOR signaling pathway.

PURPOSE: Eukaryotic translation initiation factor (EIF) plays a vital role in protein synthesis. EIF3B is a core subunit of the EIF3 family, and is overexpressed in many tumors. EIF3B is associated with an unfavorable prognosis, as well as the genesis and development of tumors. However, the potential role of EIF3B in gastric cancer (GC) remains unknown. In the current study, we explored the clinical significance and the possible mechanism of EIF3B in the progression of GC. METHODS: EIF3B expression was analyzed in 78 GC tissue samples through quantitative PCR and in 94 GC tissue samples through immunohistochemistry (IHC) staining. The correlation between EIF3B and clinicopathological features was analyzed in GC tissues. The role of EIF3B in GC progression was investigated through in vitro and in vivo assays. RESULTS: EIF3B expression was upregulated in GC tissues (73.4%, IHC). High expression of EIF3B was significantly correlated with the depth of tumor invasion, lymph node metastasis and TNM stage (P=0.000, 0.000 and 0.000, respectively). Multivariate analysis indicated that GC patients with high EIF3B expression suffered a poorer 5-year survival. EIF3B promoted GC cell proliferation and was strongly associated with proliferating cell nuclear antigen (PCNA) expression in GC samples (P=0.009). It also enhanced tumor cell migration and invasion, which were affected through epithelial-mesenchymal transition (EMT) and the Stat3 signaling pathway. Knockdown of EIF3B in GC cells suppressed the growth of xenograft tumors and lung metastatic colonization in vivo. Furthermore, gene set enrichment analysis (GSEA) and Western blot results demonstrated that EIF3B activated the PI3K/AKT/mTOR signaling pathway. CONCLUSION: Our results suggest that EIF3B plays an oncogenic role in GC progression and serves as an independent prognostic factor for GC patients.

The novel lncRNA p4516 acts as a prognostic biomarker promoting gastric cancer cell proliferation and metastasis.

Purpose: Emerging evidence has shown that long noncoding RNAs (lncRNAs) participate in oncogenesis and tumor progression. We previously found a novel lncRNA p4516 which was closely associated with prognosis by preliminary study of lncRNA expression profile from paired tumors and nontumor tissues in 198 gastric cancer (GC) patients. However, the exact biological functions and the underlying molecular mechanisms of p4516 in gastric tumorigenesis still remain unclear. Materials and methods: The RNA fluorescence in situ hybridization (RNA-FISH) analysis, cytoplasmic and nuclear RNA isolation and qRT-PCR were applied to determine the subcellular localization of p4516. Expression levels of p4516 were assessed using qRT-PCR in both GC cell lines and in 142 primary GC tissues. Correlations between p4516 expression and GC patients' clinicopathological parameters were analyzed. Gain- and loss-of-function experiments were employed to investigate the role of p4516 in proliferation, migration and invasion both in vitro and in vivo. In addition, Western blotting and immunohistochemical staining were used to examine the protein expression levels. Results: LncRNA p4516 was mainly localized in the nucleus of GC cells and p4516 tended to have higher expression levels in GC cells compared to the normal gastric mucosa-derived cells GES-1. Furthermore, higher expression levels of p4516 correlated with worse clinical outcomes in GC patients and acted as an independent prognostic biomarker. Functional analysis revealed that p4516 participated in the regulation of GC cell proliferation, invasion and migration both in vivo and in vitro. Moreover, p4516 was involved in epithelial-mesenchymal transition (EMT) in GC cells. Conclusion: Our study demonstrated the oncogenic role of novel lncRNA p4516 in the gastric carcinogenesis for the first time. High expression of p4516 may act as prognostic marker in patient with gastric cancer.

ISL1 predicts poor outcomes for patients with gastric cancer and drives tumor progression through binding to the ZEB1 promoter together with SETD7.

ISL1, a LIM-homeodomain transcription factor, serves as a biomarker of metastasis in multiple tumors. However, the function and underlying mechanisms of ISL1 in gastric cancer (GC) have not been fully elucidated. Here we found that ISL1 was frequently overexpressed in GC FFPE samples (104/196, 53.06%), and associated with worse clinical outcomes. Furthermore, the overexpression of ISL1 and loss-of-function of ISL1 influenced cell proliferation, invasion and migration in vitro and in vivo, including GC patient-derived xenograft models. We used ChIP-seq and RNA-seq to identify that ISL1 influenced the regulation of H3K4 methylation and bound to ZEB1, a key regulator of the epithelial-mesenchymal transition (EMT). Meanwhile, we validated ISL1 as activating ZEB1 promoter through influencing H3K4me3. We confirmed that a complex between ISL1 and SETD7 (a histone H3K4-specific methyltransferase) can directly bind to the ZEB1 promoter to activate its expression in GC cells by immunoprecipitation, mass spectrometry, and ChIP-re-ChIP. Moreover, ZEB1 expression was significantly positively correlated with ISL1 and was positively associated with a worse outcome in primary GC specimens. Our paper uncovers a molecular mechanism of ISL1 promoting metastasis of GC through binding to the ZEB1 promoter together with co-factor SETD7. ISL1 might be a potential prognostic biomarker of GC.

Higher autocrine motility factor/glucose-6-phosphate isomerase expression is associated with tumorigenesis and poorer prognosis in gastric cancer.

BACKGROUND: Glucose-6-phosphate isomerase (GPI) is a glycolytic-related enzyme that inter-converts glucose-6-phosphate and fructose-6-phosphate in the cytoplasm. This protein is also secreted into the extracellular matrix by cancer cells and is, therefore, also called autocrine motility factor (AMF). METHODS: To clarify the roles of AMF/GPI in gastric cancer (GC), we collected 335 GC tissues and the corresponding adjacent noncancerous tissues, performed immunohistochemical studies, and analyzed the relationship between AMF/GPI expression and the patients' clinicopathologic features. RESULTS: AMF/GPI expression was found to be significantly higher in the GC group than in the corresponding noncancerous tissue group (P<0.001). Additionally, AMF/GPI expression positively associated with a higher TNM stage and poorer prognosis in patients. Through Kaplan-Meier analysis and according to the Oncomine database, we found that AMF/GPI was overexpressed in GC tissues compared to normal mucosa, and the patients with higher AMF/GPI expression had poorer outcomes. We used AMF/GPI-silenced GC cell lines to observe how changes in AMP/GPI affect cellular phenotypes. AMF/GPI knockdown suppressed proliferation, migration, invasion, and glycolysis, and induced apoptosis in GC cells. CONCLUSION: These findings suggest that AMF/GPI overexpression is involved in carcinogenesis and promotes the aggressive phenotypes of GC cells.

Upregulation of C/EBPα contributes to colorectal cancer growth, metastasis and indicates poor survival outcome.

The function and clinical implication of transcription factor CCAAT/enhancer-binding protein α (C/EBPα) in colorectal cancer (CRC) still remains undefined. In fact, C/EBPα has long been considered as a tumor suppressor in hematopoietic system and also found lowly expressed in numerous solid tumors. However, our results here for the first time showed that C/EBPα was unexpectedly upregulated and was an independent prognostic marker for patients with CRC. We therefore aimed to explore the detailed role and mechanisms of C/EBPα in CRC. Our investigation demonstrated that C/EBPα promoted tumor growth both in vitro and in vivo. In addition, suppression of C/EBPα inhibited cell proliferation by inducing G1 phase arrest and inducing apoptosis. Also, C/EBPα enhances CRC cells migration and invasion in vitro as well as metastasis in vivo through regulating EMT. Mechanistically, C/EBPα exerts its oncogenic role by targeting c-Myc/cyclin D1 mediated by ß-catenin involved pathway and we provide evidence indicating that cytoplasmic exclusion of C/EBPα might contribute to its oncogenic function in tumor progression. In conclusion, C/EBPα acts as an oncogene in CRC and could be a potential biomarker of colon carcinogenesis.

Analysis of PD1, PDL1, PDL2 expression and T cells infiltration in 1014 gastric cancer patients.

Although immune checkpoint blockade have demonstrated promising results, their effects on gastric cancer (GC) are under investigation. Understanding the clinical significance of PD1 and its ligands' expression, together with T cell infiltration might provide clues for biomarkers screening in GC immunotherapy. Immunohistochemistry were performed on a tissue microarray including 1,014 GC specimens using PD1, PDL1 and PDL2 antibodies. T cell markers CD3 and CD8 were also stained and quantified by automated image analysis. Correlation with clinical features and outcome were analyzed after controlling for potential confounders including EBV infection, HER2, C-met and PCNA expression. 37.8% of the cases showed membranous PD-L1 expression in tumor cells and 74.9% in infiltrating immune cells. PDL1 expression rate was rather higher in patients without metastasis, in EBV positive group and those with C-met and PCNA expression. GC patients with high level PDL1 expression exhibited better survival. GC Patients with higher T cell infiltration also showed elevated PDL1, PDL2 and PD1 expression and predict favorable outcome, indicating an adaptive immune resistance mechanism may exist. The group of patients infiltrated with lower density CD3+ T cells also without PDL1 expression in tumor cells predict the worst outcome in the subgroup of different PTNM stage, which may suggest an inactive immune status. These results highlights the need to assess both PDL1 expression in all tumor context and the characterization of the GC immune microenvironment.

MicroRNA-1 acts as a tumor suppressor microRNA by inhibiting angiogenesis-related growth factors in human gastric cancer.

BACKGROUND: We recently reported that miR-1 was one of the most significantly downregulated microRNAs in gastric cancer (GC) patients from The Cancer Genome Atlas microRNA sequencing data. Here we aim to elucidate the role of miR-1 in gastric carcinogenesis. METHODS: We measured miR-1 expression in human GC cell lines and 90 paired primary GC samples, and analyzed the association of its status with clinicopathological features. The effect of miR-1 on GC cells was evaluated by proliferation and migration assay. To identify the target genes of miR-1, bioinformatic analysis and protein array analysis were performed. Moreover, the regulation mechanism of miR-1 with regard to these predicted targets was investigated by quantitative PCR (qPCR), Western blot, ELISA, and endothelial cell tube formation. The putative binding site of miR-1 on target genes was assessed by a reporter assay. RESULTS: Expression of miR-1 was obviously decreased in GC cell lines and primary tissues. Patients with low miR-1 expression had significantly shorter overall survival compared with those with high miR-1 expression (P = 0.0027). Overexpression of miR-1 in GC cells inhibited proliferation, migration, and tube formation of endothelial cells by suppressing expression of vascular endothelial growth factor A (VEGF-A) and endothelin 1 (EDN1). Conversely, inhibition of miR-1 with use of antago-miR-1 caused an increase in expression of VEGF-A and EDN1 in nonmalignant GC cells or low-malignancy GC cells. CONCLUSIONS: MiR-1 acts as a tumor suppressor by inhibiting angiogenesis-related growth factors in human gastric cancer. Downregulated miR-1 not only promotes cellular proliferation and migration of GC cells, but may activates proangiogenesis signaling and stimulates the proliferation and migration of endothelial cells, indicating the possibility of new strategies for GC therapy.

Increased expression of S100A6 promotes cell proliferation in gastric cancer cells.

S100A6 is involved in regulating the progression of cancer. S100A6 can regulate the dynamics of cytoskeletal constituents, cell growth and differentiation by interacting with binding or target proteins. The present study investigated whether S100A6 affects cell proliferation in gastric cancer cells by stimulating several downstream factors. Firstly, the expression and localization of S100A6 were investigated using immunohistochemical staining, an immunoelectron microscopy and laser confocal scanning. A ChIP-Chip assay was performed to determine the downstream factors of S100A6 using promoter Chip analysis, including approximately the -800 to +200 regions around the transcription starting point. Polymerase chain reaction analysis was performed to confirm this. It was found that the intensity of S100A6 staining was markedly higher in the cytoplasm and nucleus, and its expression level correlated with that of the Ki67 protein. The overexpression of S100A6 also promoted cell proliferation in AGS and BGC823 cell lines, detected using a Cell Counting-Kit 8 assay. In cells overexpressing S100A6, the expression levels of interleukin (IL)-8, cyclin-dependent kinase (CDK)5, CDK4, minichromosome maintenance complex component 7 (MCM7) and B-cell lymphoma 2 (Bcl2) were noticeably increased. In conclusion, the increased expression of S100A6 promoted cell proliferation by regulating the expression levels of IL-8, CDK5, CDK4, MCM7 and Bcl2 in gastric cancer cells.

Relationship between LAPTM4B Gene Polymorphism and Prognosis of Patients following Tumor Resection for Colorectal and Esophageal Cancers.

BACKGROUND: Lysosome-associated transmembrane-4 beta (LAPTM4B) is an oncogene that participates tumorgenesis in a variety of human solid tumors, and it has two alleles named as LAPTM4B*1 and *2. The present study aimed to identify the association of LAPTM4B genotype with clinicopathological features and prognosis in colorectal and esophageal cancer patients. METHOD: Genotypes of LAPTM4B were determined by PCR in 167 colon cancer cases (72 patients in a discovery cohort and 95 patients in a testing cohort), 160 rectal cancer cases and 164 esophageal cancer cases. Association between the LAPTM4B gene polymorphism and clinicopathological variables was calculated by Chi-square test or Fisher's exact test. Patient survival differences were calculated by the Kaplan-Meier method. Prognostic factors were determined with Log-rank test and Cox regression model. RESULTS: LAPTM4B *1/1 was more frequently detected in colon cancer patients with lymph node metastasis and TNM III+IV stages in total colon cancer (discovery + testing cohorts). LAPTM4B *2/2 decreased in recurrent patients in total colon cancer patients (P = 0.045). Kaplan-Meier survival curves and Log-rank test showed that LAPTM4B*1 was correlated with shorter overall survival (OS) in discovery and testing cohorts of colon cancer (P = 0.0254 and 0.0292, respectively), but not in rectal and esophageal cancer cases (P = 0.7669 and 0.9356, respectively). Multivariate analysis showed that LAPTM4B genotype was an independent prognostic factor for OS in total colon cancer [P = 0.004, hazard ratio (HR) = 0.432; 95% confidence interval (CI) = 0.243-0.768], but not in rectal and esophageal cancers (P = 0.791, HR = 1.073, 95% CI = 0.638-1.804 and 0.998, HR = 1.000, 95% CI = 0.663-1.530, respectively). CONCLUSION: These findings suggested that LAPTM4B allele *1 was a risk factor associated with poor prognosis in patients with colon cancer, but not in patients with rectal or esophageal cancers. LAPTM4B genotype status might be a useful prognostic indicator for patients that need surgical operation in colon cancer.