Calcipotriol abrogates cancer-associated fibroblast-derived IL-8-mediated oxaliplatin resistance in gastric cancer cells via blocking PI3K/Akt signaling.

Activation of vitamin D receptor (VDR) in cancer-associated fibroblasts (CAFs) has been implicated in hesitating tumor progression and chemoresistance of several human malignancies. Yet, the role of VDR in CAF-induced chemotherapy resistance of gastric cancer (GC) cells remains elusive. In this study we first conducted immunohistochemistry analysis on tissue microarrays including 88 pairs of GC and normal mucosa samples, and provided clinical evidence that VDR was mainly expressed in gastric mucous cells but almost invisible in CAFs, and VDR expression was negatively correlated with malignant clinical phenotype and advanced stages, low VDR expression confers to poor overall survival rate of patients with GC. In a co-culture system of primary CAFs and cancer cells, we showed that treatment of HGC-27 and AGS GC cells with VDR ligand calcipotriol (Cal, 500 nM) significantly inhibited CAF-induced oxaliplatin resistance. By using RNA-sequencing and Human Cytokine Antibody Array, we demonstrated that IL-8 secretion from CAFs induced oxaliplatin resistance via activating the PI3K/AKT pathway in GC, whereas Cal treatment greatly attenuated the tumor-supportive effect of CAF-derived IL-8 on GC cells. Taken together, this study verifies the specific localization of VDR in GC tissues and demonstrates that activation of VDR abrogates CAF-derived IL-8-mediated oxaliplatin resistance in GC via blocking PI3K/Akt signaling, suggesting vitamin D supplementation as a potential strategy of enhancing the anti-tumor effect of chemotherapy in GC.

Molecular signatures of tumor progression in pancreatic adenocarcinoma identified by energy metabolism characteristics.

BACKGROUND: In this study, we performed a molecular evaluation of primary pancreatic adenocarcinoma (PAAD) based on the comprehensive analysis of energy metabolism-related gene (EMRG) expression profiles. METHODS: Molecular subtypes were identified by nonnegative matrix clustering of 565 EMRGs. An overall survival (OS) predictive gene signature was developed and internally and externally validated based on three online PAAD datasets. Hub genes were identified in molecular subtypes by weighted gene correlation network analysis (WGCNA) coexpression algorithm analysis and considered as prognostic genes. LASSO cox regression was conducted to establish a robust prognostic gene model, a four-gene signature, which performed better in survival prediction than four previously reported models. In addition, a novel nomogram constructed by combining clinical features and the 4-gene signature showed high-confidence clinical utility. According to gene set enrichment analysis (GSEA), gene sets related to the high-risk group participate in the neuroactive ligand receptor interaction pathway. CONCLUSIONS: In summary, EMRG-based molecular subtypes and prognostic gene models may provide a novel research direction for patient stratification and trials of targeted therapies.

Comprehensive molecular characterization and identification of prognostic signature in stomach adenocarcinoma on the basis of energy-metabolism-related genes.

BACKGROUND: Stomach adenocarcinoma (STAD) is a leading cause of cancer deaths, but its molecular and prognostic characteristics has never been fully illustrated. AIM: To describe a molecular evaluation of primary STAD and develop new therapies and identify promising prognostic signatures. METHODS: We describe a comprehensive molecular evaluation of primary STAD based on comprehensive analysis of energy-metabolism-related gene (EMRG) expression profiles. RESULTS: On the basis of 86 EMRGs that were significantly associated to patients' progression-free survival (PFS), we propose a molecular classification dividing gastric cancer into two subtypes: Cluster 1, most of which are young patients and display more immune and stromal cell components in tumor microenvironment and lower tumor priority; and Cluster 2, which show early stages and better PFS. Moreover, we construct a 6-gene signature that can classify the prognostic risk of patients after a three-phase training test and validation process. Compared with patients with low-risk score, patients with high-risk score had shorter overall survival. Furthermore, calibration and DCA analysis plots indicate the excellent predictive performance of the 6-gene signature, and which present higher robustness and clinical usability compared with three previous reported prognostic gene signatures. According to gene set enrichment analysis, gene sets related to the high-risk group were participated in the ECM receptor interaction and hedgehog signaling pathway. CONCLUSION: Identification of the EMRG-based molecular subtypes and prognostic gene model provides a roadmap for patient stratification and trials of targeted therapies.

A Lipid Metabolism-Based Seven-Gene Signature Correlates with the Clinical Outcome of Lung Adenocarcinoma.

BACKGROUND: Herein, we tried to develop a prognostic prediction model for patients with LUAD based on the expression profiles of lipid metabolism-related genes (LMRGs). METHODS: Molecular subtypes were identified by non-negative matrix factorization (NMF) clustering. The overall survival (OS) predictive gene signature was developed and validated internally and externally based on online data sets. Time-dependent receiver operating characteristic (ROC) curve, Kaplan-Meier curve, nomogram, restricted mean survival time (EMST), and decision curve analysis (DCA) were used to assess the performance of the gene signature. RESULTS: We identified three molecular subtypes in LUAD with distinct characteristics on immune cells infiltration and clinical outcomes. Moreover, we confirmed a seven-gene signature as an independent prognostic factor for patients with LUAD. Calibration and DCA analysis plots indicated the excellent predictive performance of the prognostic nomogram constructed based on the gene signature. In addition, the nomogram showed higher robustness and clinical usability compared with four previously reported prognostic gene signatures. CONCLUSIONS: Findings in the present study shed new light on the characteristics of lipid metabolism within LUAD, and the established seven-gene signature can be utilized as a new prognostic marker for predicting survival in patients with LUAD.

DUBR suppresses migration and invasion of human lung adenocarcinoma cells via ZBTB11-mediated inhibition of oxidative phosphorylation.

Long noncoding RNAs (lncRNAs) are involved in a variety of cancers, but the role of LncRNA DUBR in lung adenocarcinoma (LUAD), the most prevalent form of lung cancer, remains unclear. In this study we investigated the expression of DUBR in LUAD to ascertain its association with the clinical pathology and prognosis of LUAD. Analysis of mRNA expression in The Cancer Genome Atlas (TCGA) LUAD database and in-house LUAD cohort (n = 94) showed that DUBR was significantly downregulated in LUAD, and was associated with poor prognosis. In LUAD cell lines (H1975, A549), overexpression of DUBR significantly suppressed the migration and invasion of the LUAD cells. We demonstrated that c-Myc could bind to the promoter of DUBR, and transcriptionally suppressed its expression. Knockdown of c-Myc almost completely blocked the invasion and migration of LUAD cells, whereas knockdown of DUBR partially rescued c-Myc-knockdown suppressed cell migration and invasion. Furthermore, DUBR overexpression significantly increased the expression of a downstream protein of DUBR, zinc finger, and BTB domain containing 11 (ZBTB11), in H1975 and A549 cells; knockdown of ZBTB11 partially rescued the DUBR-overexpression suppressed cell migration and invasion; knockdown of c-Myc significantly upregulated the expression of ZBTB11 in LUAD cells. Finally, we revealed that DUBR/ZBTB11 axis suppressed oxidative phosphorylation in LUAD cells. In short, we demonstrate that c-Myc/DUBR/ZBTB11 axis suppresses migration and invasion of LUAD by attenuating cell oxidative phosphorylation, which provides new insights into the regulatory mechanism of DUBR.

Atezolizumab prolongs overall survival over docetaxel in advanced non-small-cell lung cancer patients harboring STK11 or KEAP1 mutation.

Somatic mutations of STK11 or KEAP1 are associated with poor clinical outcomes for advanced non-small-cell lung cancer (aNSCLC) patients receiving immune checkpoint inhibitors (ICIs), chemotherapy, or targeted therapy. Which treatment regimens work better for STK11 or KEAP1 mutated (SKmut) aNSCLC patients is unknown. In this study, the efficacy of atezolizumab versus docetaxel in SKmut aNSCLC was compared. A total of 157 SKmut aNSCLC patients were identified from POPLAR and OAK trials, who were tested by blood-based FoundationOne next-generation sequencing assay. Detailed clinical data and genetic alterations were collected. Two independent cohorts were used for biomarker validation (n = 30 and 20, respectively). Median overall survival was 7.3 months (95% confidence interval [CI], 4.8 to 9.9) in the atezolizumab group versus 5.8 months (95% CI, 4.4 to 7.2) in the docetaxel group (adjusted hazard ratio [HR] for death, 0.70; 95% CI, 0.49 to 0.99; P = .042). Among atezolizumab-treated patients, objective response rate, disease control rate, and durable clinical benefit were higher when blood tumor mutation burden (bTMB) and PD-L1 being higher (biomarker 1, n = 61) or with FAT3 mutation-positive tumors (biomarker 2, n = 83) than otherwise. The interactions for survival between these two biomarkers and treatments were significant, which were further validated in two independent cohorts. In SKmut patients with aNSCLC, atezolizumab was associated with significantly longer overall survival in comparison to docetaxel. Having FAT3 mutation or high TMB and PD-L1 expression potentially predict favorable response in SKmut patients receiving atezolizumab.

GCNT4 is Associated with Prognosis and Suppress Cell Proliferation in Gastric Cancer.

BACKGROUND: GCNT4 is a member of the glucosaminyl (N-acetyl) transferases family that has been implicated in multiple human malignancies. However, the role of GCNT4 in gastric cancer (GC) is unknown. In this present study, we aimed to explore the role and clinicopathological correlation of GCNT4 in GC. MATERIALS AND METHODS: We first evaluated the dysregulation of GCNT4 in The Cancer Genome Atlas (TCGA) and then we performed RT-qPCR and immunohistochemistry to validate the results in a cohort of in-house patients. The clinicopathological correlation and function of GCNT4 in GC were also analysed. RESULTS: GCNT4 was found to be significantly downregulated in GC. In addition, GCNT4 expression correlated with tumour depth, nervous invasion and pathological tumor-node-metastasis (pTNM) stage. Moreover, lower GCNT4 levels conferred poor overall survival (OS) and disease-free survival (DFS) to GC patients. Multivariate Cox regression analysis revealed that GCNT4 protein expression is an independent prognostic factor for OS in patients with GC. Further functional experimental results revealed that overexpression of GCNT4 appears to halt GC cell proliferation and the cell cycle. CONCLUSION: Altogether, these findings indicated that GCNT4 regulates the GC cell cycle and have important implications for the selection of therapeutic targets to prevent tumour proliferation.

Prognostic and Predictive Value of Blood Tumor Mutational Burden in Patients With Lung Cancer Treated With Docetaxel.

BACKGROUND: Biomarkers for chemotherapy efficacy in non-small cell lung cancer (NSCLC) are lacking. This retrospective study assesses the association between blood-based tumor mutational burden (bTMB) and clinical benefit of chemotherapy. METHODS: Clinical and targeted next-generation sequencing data from the OAK trial (training set; n=318) and POPLAR trial (validation set; n=106) in the docetaxel arm were analyzed. The cutoff value of bTMB for outcome prediction was determined based on a time-dependent receiver operating characteristic curve in the training set, and propensity score matching (PSM) was conducted. The primary outcome was overall survival (OS). Durable clinical benefit (DCB) was defined as OS lasting >12 months. Interaction between treatment and bTMB was assessed in the combined set. RESULTS: A lower bTMB was observed in patients with DCB compared with no durable benefit, and in those with a partial response and stable disease compared with progressive disease. The optimized cutoff value of bTMB for predicting OS was 7 single-nucleotide variants per megabase. In the training set, a low bTMB was significantly associated with longer OS and progression-free survival (PFS). The prognostic value of bTMB was confirmed in the validation set and PSM set. The interaction between bTMB and treatment was significant for PFS (interaction P=.043) in the combined set. Mutations in KEAP1 were associated with high bTMB and a lack of benefit from chemotherapy. CONCLUSIONS: Low bTMB is associated with a survival advantage in patients with NSCLC treated with docetaxel, suggesting the prognostic and predictive potential of bTMB for determining chemotherapy efficacy.

A non-linear association between blood tumor mutation burden and prognosis in NSCLC patients receiving atezolizumab.

A significant association between high blood-based tumor mutational burden (bTMB) and improved progression-free survival (PFS) was observed in advanced non-small cell lung cancer (NSCLC) receiving atezolizumab. However, this result was unrepeatable in a recent prospective study. We hypothesized that there might be a non-linear association between bTMB and survival. This study used the clinical and genetic data from POPLAR (n = 105, training set) and OAK (n = 324, validation set) trials. The non-linear association between bTMB and survival was assessed using restricted cubic spline (RCS). The cutoff values for bTMB were calculated via X-tile software. Non-linear relationships were observed between bTMB and PFS and overall survival (OS) in RCS plots (both Pnon-linearity < 0.001). The optimal cutoff values of bTMB for predicting PFS and OS were 7 and 14 mutations/Mb, respectively. The median PFS and OS of patients with low and high bTMB were significantly longer than those of patients with medium bTMB in the training, validation, and combined sets. Low and high bTMB were also associated with longer PFS and OS in high-programmed death-ligand 1 (PD-L1) expression population. In conclusion, there was a positive non-linear association between bTMB and survival in NSCLC patients receiving atezolizumab. Patients with low bTMB could also derive benefit from immunotherapy.

Advanced Non-Small Cell Lung Cancer Patients With Low Tumor Mutation Burden Might Derive Benefit From Immunotherapy.

The aim of this study is to investigate the association between tumor mutation burden (TMB) and survival in non-small cell lung cancer (NSCLC) patients with anti-programmed cell death protein 1 and anti-programmed death-ligand 1 blockade. Two retrospective cohorts and The Cancer Genome Atlas NSCLC data set were included in this study. The restricted cubic spline analysis was used to explore the association between TMB and survival. The cutoff values for TMB were determined by X-tile software. Primary outcomes were overall survival (OS). The associations between TMB and intratumor heterogeneity, number of segments, fraction of genome alterations, aneuploidy score, and T-cell populations were also investigated. In the restricted cubic spline plots, TMB showed an inverted U-shaped curve with OS. The median OS in the low TMB group was significantly longer than those in the medium TMB group. In The Cancer Genome Atlas NSCLC data set, low TMB was also associated with longer OS in comparison with medium TMB. Furthermore, NSCLC patients with low TMB had significantly lower intratumor heterogeneity, number of segments, fraction of genome alterations, aneuploidy score, T-helper type 2 (Th2) cells, and CD8 T cells, but higher levels of Th1 and Th17 cells. Low TMB might be a prognostic factor for NSCLC patients receiving anti-programmed cell death protein 1/programmed death-ligand 1 immunotherapy.

Emerging roles of long non-coding RNAs in tumor metabolism.

Compared with normal cells, tumor cells display distinct metabolic characteristics. Long non-coding RNAs (lncRNAs), a large class of regulatory RNA molecules with limited or no protein-coding capacity, play key roles in tumorigenesis and progression. Recent advances have revealed that lncRNAs play a vital role in cell metabolism by regulating the reprogramming of the metabolic pathways in cancer cells. LncRNAs could regulate various metabolic enzymes that integrate cell malignant transformation and metabolic reprogramming. In addition to the known functions of lncRNAs in regulating glycolysis and glucose homeostasis, recent studies also implicate lncRNAs in amino acid and lipid metabolism. These observations reveal the high complexity of the malignant metabolism. Elucidating the metabolic-related functions of lncRNAs will provide a better understanding of the regulatory mechanisms of metabolism and thus may provide insights for the clinical development of cancer diagnostics, prognostics and therapeutics.

The prognostic value of age in non-metastatic gastric cancer after gastrectomy: a retrospective study in the U.S. and China.

Purpose: We explored the influence of age on clinicopathologic features and survival of patients with M0 gastric cancer (GC). Methods: 16856 GC patients from Surveillance, Epidemiology and End Results (SEER) database and 1037 GC patients from Chinese multiple centers were enrolled in the U.S. and Chinese cohort, respectively. 50-year-old was treated as cutoff age. Propensity score method was used to carry out a 1:1 paired match. Results: In the U.S. cohort, we found that younger patients presented poor tumor behavior. However, in spite of worse outcome in stage I~IV cohort, young group showed better 3-year survival in M0 patients, especially for those who underwent a total gastrectomy. In a matched analysis, a better prognosis was still observed in younger group. The prognostic value of age was also validated in M0 GC patients with gastrectomy in Chinese cohort. Conclusions: In spite of the worse outcome in survival curve of stage I~IV GC cohort, young patients with gastrectomy presented favorable survival in M0 subgroup. It is also applicable in China. Early diagnosis and treatment should be taken seriously in young GC patients since they often possess poorer characteristics but benefited more from gastrectomy.

Linc00152 promotes Cancer Cell Proliferation and Invasion and Predicts Poor Prognosis in Lung adenocarcinoma.

Background: The long non-coding RNA Linc00152 stimulates tumor progression in cancer. However, its clinical significance and biological functions in lung adenocarcinoma remains unknown. We evaluate the expression of Linc00152 in lung adenocarcinoma and its possible correlation with clinicopathologic features and patient survival to reveal its biological effects in cancer progression and prognosis. Methods: Total RNA extraction was performed on 110 pairs of lung adenocarcinoma and adjacent normal tissue samples, and then RT-qPCR was conducted. Chi-square test analysis was used to calculate the correlation between pathological parameters and the Linc00152 mRNA levels. Kaplan-Meier and Cox proportional hazards analyses were used to analyze the overall survival (OS) and disease-free survival (DFS) rates. We also detected the potential functional effects of overexpression and knockdown of Linc00152 in vitro cell proliferation, tumor cell invasion and migration, as well as in vivo nude mouse xenograft and metastasis models. Results: The Linc00152 expression levels were higher in lung adenocarcinoma samples than in the adjacent normal tissues. Linc00152 expression levels tightly correlated with lymph node metastasis station, remote metastasis and TNM staging. The Kaplan-Meier analysis suggested that high Linc00152 expression caused significantly poorer OS and DFS rates, and a multivariate analysis revealed that Linc00152 was an independent risk factor for both DFS and OS. Overexpression of Linc00152 in lung cancer cells stimulated proliferation, tumor cell invasion and migration. Knockdown of Linc00152 inhibited cell growth and cell invasion and migration. Finally, Linc00152 knockdown inhibited lung tumor growth and tumor metastasis in nude mice models. Conclusions: Our study suggests that Linc00152 independently predicts poor prognosis and promotes tumor progression in lung adenocarcinoma. Linc00152 needs to be considered as a potential molecular target in future cancer pharmacology.

A Positive Feedback Loop of lncRNA-PVT1 and FOXM1 Facilitates Gastric Cancer Growth and Invasion.

Purpose: The long, noncoding RNA (lncRNA) PVT1 is an important epigenetic regulator with a critical role in human tumors. Here, we aimed to investigate the clinical application and the potential molecular mechanisms of PVT1 in gastric cancer tumorigenesis and progression.Experimental Design: The expression level of PVT1 was determined by RT-qPCR analysis in 190 pairs of gastric cancer tissues and adjacent normal gastric mucosa tissues (ANT). The biologic functions of PVT1 were assessed by in vitro and in vivo functional experiments. RNA protein pull-down assays and LS/MS mass spectrometry analysis were performed to detect and identify the PVT1- interacting protein FOXM1. Protein-RNA immunoprecipitation assays were conducted to examine the interaction of FOXM1 and PVT1 Chromatin immunoprecipitation (ChIP) and luciferase analyses were utilized to identify the binding site of FOXM1 on the PVT1 promoter.Results: The lncRNA PVT1 was significantly upregulated in gastric cancer tissues compared with ANTs. High expression of PVT1 predicted poor prognosis in patients with gastric cancer. PVT1 enhanced gastric cancer cell proliferation and invasion in vitro and in vivoPVT1 directly bound FOXM1 protein and increased FOXM1 posttranslationally. Moreover, PVT1 is also a FOXM1-responsive lncRNA, and FOXM1 directly binds to the PVT1 promoter to activate its transcription. Finally, PVT1 fulfilled its oncogenic functions in a FOXM1-mediated manner.Conclusions: Our study suggests that PVT1 promotes tumor progression by interacting with FOXM1. PVT1 may be a valuable prognostic predictor for gastric cancer, and the positive feedback loop of PVT1-FOXM1 could be a therapeutic target in pharmacologic strategies. Clin Cancer Res; 23(8); 2071-80. ©2016 AACR.

Circulating Long RNAs in Serum Extracellular Vesicles: Their Characterization and Potential Application as Biomarkers for Diagnosis of Colorectal Cancer.

BACKGROUND: Long noncoding RNA (lncRNA) and mRNAs are long RNAs (≥200 nucleotides) compared with miRNAs. In blood, long RNAs may be protected by serum extracellular vesicles, such as apoptotic bodies (AB), microvesicles (MV), and exosomes (EXO). They are potential biomarkers for identifying cancer. METHODS: Sera from 76 preoperative colorectal cancer patients, 76 age- and sex-matched healthy subjects, and 20 colorectal adenoma patients without colorectal cancer were collected. We investigated the distribution of long RNAs into the three vesicles. Seventy-nine cancer-related long RNAs were chosen and detected using qPCR. RESULTS: The quantity of long RNA has varying distribution among three subtypes of extracellular vesicles in serum. Most mRNA and lncRNA genes had higher quantity in EXOs than that in ABs and MVs, whereas MVs contain lowest quantity. We investigated 79 long RNAs chosen from The Cancer Genome Atlas and the LncRNADisease database in the sera of healthy patients, and those with colorectal cancer. In the training and test sets, the AUCs were 0.936 and 0.877, respectively. The AUC of total serum RNA was lower (0.857) than that of exosomal RNA in the same samples (0.936). CONCLUSION: The present study shows that exosomal mRNAs and lncRNAs in serum could be used as biomarkers to detect colorectal cancer. IMPACT: Among three types of vesicles in sera, EXOs were the richest reservoir for almost all measured long RNAs. The combination of two mRNAs, KRTAP5-4 and MAGEA3, and one lncRNA, BCAR4, could be potential candidates to detect colorectal cancer. Cancer Epidemiol Biomarkers Prev; 25(7); 1158-66. ©2016 AACR.

Long non-coding RNA Linc00152 is a positive prognostic factor for and demonstrates malignant biological behavior in clear cell renal cell carcinoma.

Accumulating evidence demonstrates that lncRNAs play important roles in regulating gene expression and are involved in various pathological processes. In the present study, we screened the lncRNAs profile in clear cell renal cell carcinoma (ccRCC) from The Cancer Genome Atlas (TCGA) database, and got linc00152, a differentially expressed lncRNA that haven't been reported in ccRCC. To further explore its role in ccRCC, the level of Linc00152 was detected in 77 paired ccRCC tissues and renal cancer cell lines by qRT-PCR, and its association with overall survival was assessed by statistical analysis. Linc00152 expression was significantly up-regulated in cancerous tissues and cell lines compared with normal counterparts, and high Linc00152 expression was closely associated with advanced TNM stage. Moreover, Linc00152 was found to be able to serve as an independent predictor of overall survival. Further experiments demonstrated that overexpression of Linc00152 can significantly promote cell proliferation and invasion, inhibit cell cycle arrest in G1 phase and dramatically decrease apoptosis in both 786O and Caki-2 cell lines, whereas the opposite results were observed with attenuated Linc00152 expression. Our data suggest that Linc00152 is a novel molecule involved in ccRCC progression as well as a potential prognostic biomarker and therapeutic target.

Upregulation of the Non-Coding RNA OTUB1-isoform 2 Contributes to Gastric Cancer Cell Proliferation and Invasion and Predicts Poor Gastric Cancer Prognosis.

BACKGROUND: The deubiquitinase OTUB1 plays critical oncogenic roles and facilitates tumor progression in cancer. However, less is known regarding the aberrant expression, clinical significance and biological functions of the non-coding RNA OTUB1-isoform 2. We aimed to evaluate the OTUB1-isoform 2 levels in gastric cancer and their possible correlation with clinicopathologic features and patient survival to reveal its biological effects in gastric cancer progression. METHODS: Total RNA extraction was performed on 156 gastric cancer case samples, and RT-qPCR was conducted. Chi-square test analysis was used to calculate the correlation between pathological parameters and the OTUB1-isoform 2 mRNA levels. Kaplan-Meier and Cox proportional hazards analyses were used to analyze the overall survival (OS) and disease-free survival (DFS) rates. Nuclear and cytoplasmic RNAs were isolated to detect the subcellular localization of OTUB1-isoform 2. We also assessed whether overexpression of OTUB1-isoform 2 influenced in vitro cell proliferation, cell cycle progression, tumor cell invasion and migration, as well as in vivo nude mouse xenograft and metastasis models. RESULTS: The OTUB1-isoform 2 expression levels were higher in the gastric cancer samples than in the paratumorous gland samples. OTUB1-isoform 2 expression levels tightly correlated with tumor size, lymph node metastasis and TNM staging. Higher OTUB1-isoform 2 expression levels led to significantly poorer OS and DFS rates, and a multivariate analysis revealed that OTUB1-isoform 2 was an independent risk factor for DFS. OTUB1-isoform 2 was predominantly localized in the cell nucleus. Ectopic overexpression of OTUB1-isoform 2 in gastric cancer cells stimulated proliferation by inducing G1-S transition, suppression of cell apoptosis and promotion of tumor cell invasion and migration. Finally, OTUB1-isoform 2 overexpression promoted tumor growth and tumor metastasis in nude mice models. CONCLUSIONS: Our study suggests that OTUB1-isoform 2 independently predicts poor prognosis and promotes tumor progression in gastric cancer. The non-coding RNA OTUB1-isoform 2 should be targeted in future molecular therapies.

Pituitary tumor-transforming gene-1 serves as an independent prognostic biomarker for gastric cancer.

BACKGROUND: Pituitary tumor-transforming gene-1 (PTTG1) is a transcription factor that can affect transcriptional activity, angiogenesis, and cell senescence. We examined PTTG1 mRNA and protein expression in gastric cancer (GC) cell lines and tissues to determine its value as a biomarker for GC diagnosis and therapy. METHODS: PTTG1 mRNA expression from 78 GC cases and paired adjacent normal mucosa (PCR cohort) as well as from five gastric cell lines was assessed using qRT-PCR. Nuclear and cytoplasmic RNA were extracted from two gastric cell lines to determine PTTG1 mRNA localization. PTTG1 protein expression from 98 GC cases, their paired adjacent normal mucosa, and 23 gastric intraepithelial neoplasia (GIN) cases was examined using immunohistochemistry (IHC cohort). The correlation between PTTG1 mRNA and protein expression and GC clinicopathological parameters was analyzed. RESULTS: PTTG1 mRNA expression in GC tissues and cell lines was significantly increased compared with adjacent normal gastric mucosa and normal gastric mucous cell lines (p < 0.05). PTTG1 expression was nuclear and cytoplasmic, with higher cytoplasmic expression. PTTG1 immunostaining significantly differed in GC (95.66 ± 20.65), GIN (84.00 ± 34.16), and normal adjacent mucosa (28 ± 22.25) (p < 0.001). Multivariate Cox regression analysis revealed that PTTG1 mRNA and protein expression are independent prognostic factors for GC patient survival. CONCLUSION: Our results suggest that PTTG1 is a promising target for GC diagnosis and therapy.

Reciprocal repression between TUSC7 and miR-23b in gastric cancer.

Recently, long noncoding RNAs (lncRNAs) were demonstrated to play important regulatory roles in biological processes and cancer biology. However, the overall pathophysiological contribution of lncRNAs to gastric cancer (GC) remains largely unknown. In this study, differentially expressed lncRNAs in GC and paired adjacent normal tissue samples were identified by microarray and were validated using quantitative real-time polymerase chain reaction (qRT-PCR). One particular lncRNA, tumour suppressor candidate 7 (TUSC7), was analyzed in sequential large cohorts, and the Kaplan-Meier method with the log-rank test for comparisons was used to analyse the survival data. The results indicated that TUSC7 was downregulated in GC samples and was an independent prognostic indicator of disease-free survival (DFS) and disease-specific survival (DSS) in GC patients. Applying loss-of-function and gain-of-function approaches, we determined that TUSC7 suppressed tumour cell growth in vitro and in vivo. Furthermore, we showed that TUSC7 was a direct transcriptional target of p53 via interaction of p53 with the putative p53-response element in the upstream region of TUSC7. Finally, we demonstrated reciprocal repression between TUSC7 and miR-23b; in contrast to TUSC7, miR-23b promoted cell growth. The results indicated that TUSC7 is a p53-regulated tumour suppressor that acts in part by repressing miR-23b and that TUSC7 may be a key regulatory hub in GC.

Circulating CUDR, LSINCT-5 and PTENP1 long noncoding RNAs in sera distinguish patients with gastric cancer from healthy controls.

The examination of circulating nucleic acids (CNAs) is an emerging noninvasive diagnostic technique. However, it is unclear if serum long noncoding RNAs (lncRNAs) represent a novel marker to detect gastric cancer (GC). In this study, we measured 39 candidate cancer-associated lncRNAs by reverse transcription and quantitative polymerase chain reaction (RT-qPCR) in sera from 110 patients with GC, 106 age- and sex-matched healthy subjects and 15 patients with gastric peptic ulcer, markers were validated and assessed by RT-qPCR. The correlation of the expression levels of the candidate serum lncRNAs with clinical parameters of GC patients was performed. A three-lncRNA signature, including CUDR, LSINCT-5 and PTENP1, was identified that may be potential diagnostic marker for GC. The areas under the receiver operating characteristic (ROC) curve for this serum three-lncRNA signature were 0.920 and 0.829 for the two sets of serum samples. Moreover, a risk model for the serum three-lncRNA signature demonstrated that healthy samples can be distinguished from early GC samples. Three-lncRNA signature in serum was identified as diagnostic marker for GC. This work may facilitate the detection of GC and serve as the basis for further studies of the clinical value of serum lncRNAs in maintaining surveillance and forecasting prognosis.