Metastatic pathway-specific transcriptome analysis identifies MFSD4 as a putative tumor suppressor and biomarker for hepatic metastasis in patients with gastric cancer

MFSD2A Overexpression Inhibits Hepatocellular Carcinoma Through TGF-β/Smad Signaling

Hepatocellular carcinoma (HCC) is a common primary malignancy of the liver and has a high mortality. Major facilitator superfamily domain containing 2 (MFSD2A) was previously demonstrated to inhibit tumor progression in several cancers. Here, we elucidated the association between MFSD2A expression and HCC progression and also investigated the underlying mechanism. The online tools were utilized to evaluate MFSD2A expression in HCC samples and predict the prognostic significance of MFSD2A in HCC patients. The biological role of MFSD2A in HCC cellular processes was examined by colony formation, wound healing, transwell, and western blotting. The in vivo role of MFSD2A in HCC was investigated in a xenograft tumor model. The miRNAs and RNA-binding proteins potentially targeting MFSD2A were identified using bioinformatics prediction tools. Luciferase reporter, RNA immunoprecipitation, actinomycin D, and immunofluorescence assays were performed to investigate the molecule mechanisms of MFSD2A. Transforming growth factor (TGF)-β1/Small mothers against decapentaplegic (Smad) signaling was detected using western blot analysis. We found that MFSD2A expression was significantly downregulated in HCC patients and cells and its downregulation predicted a poor prognosis. MFSD2A overexpression repressed HCC cell proliferation, migration, invasion, the epithelial-to-mesenchymal transition in vitro, as well as inhibited HCC tumor growth in vivo. MFSD2A was targeted by miR-3189-3p. High-density lipoprotein binding protein (HDLBP) inhibited MFSD2A expression by binding to and destabilizing MFSD2A mRNA. MFSD2A significantly suppressed activation of TGF-β/Smad signaling in HCC cells. Knockdown of MFSD2A abrogated the inhibitory effect of miR-3189-3p inhibitor on HCC cellular processes, and overexpression of MFSD2A reversed the tumor-promoting effect of HDLBP overexpression. Overall, MFSD2A exerts a tumor-inhibiting effect in HCC via suppression of TGF-β/Smad signaling, suggesting that MFSD2A may be a promising target for HCC therapy.

Major Facilitator Superfamily Domain Containing 12 Is Overexpressed in Lung Cancer and Exhibits an Oncogenic Role in Lung Adenocarcinoma Cells

Major facilitator superfamily domain containing 12 (MFSD12) regulates lysosomal cysteine import and promotes the proliferation and survival of melanoma cells. However, the expression and function of MFSD12 in other cancers, particularly in lung cancer, remain unclear. The expression of MFSD12 across various types of cancers and corresponding control tissues was examined using TIMER. MFSD12 expression in lung adenocarcinoma (LUAD) and its correlation with distinct clinicopathological features of LUAD patients were analyzed with UALCAN. The correlation between MFSD12 expression and survival of LUAD patients was assessed using the R package, survival, and the relationship between MFSD12 expression and immune infiltration status in LUAD was investigated using CIBERSORT. In addition, MFSD12 expression was knocked down in PC9 LUAD cells and their proliferation, capacity for expansion, cell cycle, apoptosis, and migration/invasion were evaluated through CCK-8 assays, colony formation assays, 7-AAD staining, Annexin V/PI staining, and Transwell assays, respectively. The stemness of these PC9 cells was determined through Western blotting, flow cytometry, and tumor sphere formation assays. MFSD12 mRNA levels were significantly elevated in multiple types of cancers, including LUAD. MFSD12 expression was also positively correlated with cancer stage, nodal metastasis, and infiltration of various immune cells in LUAD, and high MFSD12 levels predicted poor survival among LUAD patients. Knockdown of MFSD12 in PC9 cells resulted in decreased proliferation, attenuated colony formation capacity, cell cycle arrest, elevated apoptosis, impaired migration/invasion, and reduced stemness in PC9 cells. MFSD12 is an oncogene in LUAD.

A bibliometric analysis of gastric cancer liver metastases: advances in mechanisms of occurrence and treatment options

BACKGROUND

Gastric cancer (GC) is the fifth most commonly diagnosed cancer worldwide, and its poor prognosis is predominantly attributed to distant metastasis. Liver is the primary site of GC metastasis. However, there is no universally approved treatment regimen for liver metastasis in GC. The aim of this article is to review the current research status and trends of liver metastasis of gastric cancer worldwide.

METHODS

We utilized the Web of Science Core Collection database to identify articles on liver metastasis from GC published between 2000 and 2022. We used bibliometric methods to analyze authors, institutions, countries, journals, and references through CiteSpace and VOSviewer. A total of 1,003 articles were included in this study.

RESULTS

Japan published the most articles in the field, followed by China. Nagoya University is the leading institution in the field of liver metastases in GC. Yasuhiro Kodera from Japan has made significant achievements in this area. We identified Gastric Cancer to be the most influential journal in this field. Using cluster analysis, the keywords were divided into four major clusters:(1) the molecular mechanism of gastric cancer liver metastasis (2) prognosis (3) liver resection (4) chemotherapy.

CONCLUSION

Our study systematically summarizes the results of gastric cancer liver metastasis research from 2000 to 2022 and describes and predicts research hotspots and trends on a global scale. Research on the molecular mechanisms of gastric cancer liver metastasis will become a hot topic in the future, and the expansion of the surgical treatment scope and the advancement of translational therapy will benefit more patients.

Molecular mechanism and potential therapeutic targets of liver metastasis from gastric cancer

Gastric cancer (GC) is characterized by high invasion and poor prognosis. The occurrence of liver metastasis seriously affects advanced GC prognosis. In recent years, great progress has been made in the field of GC liver metastasis. The abnormal expression of related genes leads to the occurrence of GC liver metastasis through metastasis cascades. The changes in the liver microenvironment provide a pre-metastasis condition for GC cells to colonize and grow. The development of several potential therapeutic targets might provide new therapeutic strategies for its treatment. Therefore, we reviewed the regulatory mechanism of abnormal genes mediating liver metastasis, the effect of liver resident cells on liver metastasis, and potential therapeutic targets, hoping to provide a novel therapeutic option to improve the quality of life and prognosis of GC patients with liver metastasis.

MFSD4A inhibits the malignant progression of nasopharyngeal carcinoma by targeting EPHA2

DNA Methylation can lead to abnormal gene expression. In the present study, we investigated whether the expression of methylated MFSD4A (major facilitator superfamily domain containing 4 A) was downregulated in nasopharyngeal carcinoma (NPC) and whether it is associated with malignant progression and poor prognosis of NPC. Bioinformatic analysis, bisulfite pyrosequencing, quantitative real-time reverse transcription PCR, and western blotting assays were performed to explore the relationship between hypermethylation of MFSD4A and its expression in NPC. The role of MFSD4A in NPC was verified by Cell Cycle Kit 8, transwell assays and flow cytometry in vitro and by animal experiments in vivo. Mass spectrometry, co-immunoprecipitation, and immunofluorescence assays were applied to explore the mechanism by which MFSD4A inhibits NPC. The prognostic significance of MFSD4A or EPHA2 was investigated by immunohistochemical analysis of clinical specimens. Hypermethylation of the promoter region of MFSD4A led to decreased expression of MFSD4A. When MFSD4A expression was upregulated or downregulated, the proliferation, apoptosis, migration, and invasion abilities of NPC cells were altered accordingly. Mechanistically, MFSD4A could specifically bind to and degrade EPH receptor A2 (EPHA2) by recruiting ring finger protein 149 (RNF149), which led to alterations in the EPHA2-mediated PI3K-AKT-ERK1/2 pathway and epithelial-mesenchymal transition (EMT), thereby affecting NPC progression. Clinically, high MFSD4A expression or low-EPHA2 expression was associated with better prognosis for patients with NPC. In all, reduced MFSD4A expression in NPC is caused by promoter hypermethylation. MFSD4A or EPHA2 expression is associated with the malignant biological behavior and prognosis of NPC. MFSD4A is a promising potential therapeutic target for NPC.

Identification of an evolutionarily conserved domain in Neurod1 favouring enteroendocrine versus goblet cell fate

ARP/ASCL transcription factors are key determinants of cell fate specification in a wide variety of tissues, coordinating the acquisition of generic cell fates and of specific subtype identities. How these factors, recognizing highly similar DNA motifs, display specific activities, is not yet fully understood. To address this issue, we overexpressed different ARP/ASCL factors in zebrafish ascl1a-/- mutant embryos to determine which ones are able to rescue the intestinal secretory lineage. We found that Ascl1a/b, Atoh1a/b and Neurod1 factors are all able to trigger the first step of the secretory regulatory cascade but distinct secretory cells are induced by these factors. Indeed, Neurod1 rescues the enteroendocrine lineage while Ascl1a/b and Atoh1a/b rescue the goblet cells. Gain-of-function experiments with Ascl1a/Neurod1 chimeric proteins revealed that the functional divergence is encoded by a 19-aa ultra-conserved element (UCE), present in all Neurod members but absent in the other ARP/ASCL proteins. Importantly, inserting the UCE into the Ascl1a protein reverses the rescuing capacity of this Ascl1a chimeric protein that cannot rescue the goblet cells anymore but can efficiently rescue the enteroendocrine cells. This novel domain acts indeed as a goblet cell fate repressor that inhibits gfi1aa expression, known to be important for goblet cell differentiation. Deleting the UCE domain of the endogenous Neurod1 protein leads to an increase in the number of goblet cells concomitant with a reduction of the enteroendocrine cells, phenotype also observed in the neurod1 null mutant. This highlights the crucial function of the UCE domain for NeuroD1 activity in the intestine. As Gfi1 acts as a binary cell fate switch in several tissues where Neurod1 is also expressed, we can envision a similar role of the UCE in other tissues, allowing Neurod1 to repress Gfi1 to influence the balance between cell fates.

It is not yet clear how highly related factors like the ARP/Ascl factors display specific activities even though they recognize the same consensus DNA motif. This specificity could be provided by their cellular environment or by intrinsic properties of the factors themselves. To distinguish between these two possibilities, we have expressed several ARP/Ascl factors in the ascl1a-/- mutant to determine which ones are able to rescue the intestinal secretory defects. We found that Ascl1a/b and Atoh1a/b are able to rescue the goblet cells while Neurod1 rescues the enteroendocrine lineage. Furthermore, we show that the specific Neurod1 activity is conferred by the presence of a 19-aa ultra-conserved element (UCE), present in all vertebrate Neurod members but absent in all the other ARP/ASCL proteins. This UCE domain, so far uncharacterized, acts as a goblet cell fate repressor and inhibits gfi1aa expression, known to be important for goblet cell differentiation. Inserting the UCE into Ascl1a protein reverses the rescuing capacity of this chimeric protein that cannot rescue the goblet cells anymore but can efficiently rescue the enteroendocrine cells. This study therefore highlights an unique intrinsic property of Neurod1 allowing it to repress Gfi1 to influence the balance between cell fates. As Gfi1 acts as a binary cell fate switch in several tissues where Neurod1 is also expressed, we can envision a similar role of the UCE in other tissues, allowing Neurod1 to repress Gfi1 to influence the balance between cell fates.

Identification of Differentially Expressed Genes Reveals BGN Predicting Overall Survival and Tumor Immune Infiltration of Gastric Cancer

Gastric cancer (GC) is one of the most widely occurring malignancies worldwide. Although the diagnosis and treatment strategies of GC have been greatly improved in the past few decades, the morbidity and lethality rates of GC are still rising due to lacking early diagnosis strategies and powerful treatments. In this study, a total of 37 differentially expressed genes were identified in GC by analyzing TCGA, GSE118897, GSE19826, and GSE54129. Using the PPI database, we identified 17 hub genes in GC. By analyzing the expression of hub genes and OS, MFAP2, BGN, and TREM1 were related to the prognosis of GC. In addition, our results showed that higher levels of BGN exhibited a significant correlation with shorter OS time in GC. Nomogram analysis showed that the dysregulation of BGN could predict the prognosis of GC. Moreover, we revealed that BGN had a markedly negative correlation with B cells but had positive correlations with CD8⁺ T cells, CD4⁺ T cells, macrophages, neutrophils, and dendritic cells in GC samples. The pan-cancer analysis demonstrated that BGN was differentially expressed and related to tumor-infiltrating immune cells across human cancers. This study for the first time comprehensively revealed that BGN was a potential biomarker for the prediction of GC prognosis and tumor immune infiltration.

Epigenetic Study of Esophageal Carcinoma Based on Methylation, Gene Integration and Weighted Correlation Network Analysis

Purpose

Esophageal carcinoma is a common and highly metastatic malignant tumor of the digestive tract. The aim of the present study was to identify potential molecular markers of esophageal carcinoma that may help its diagnosis and treatment.

Materials and Methods

First, mRNA and DNA methylation data were downloaded from The Cancer Genome Atlas (TCGA) database for the identification of differentially expressed genes (DEGs) and DNA methylation analysis. Secondly, Weighted Gene Co-Expression Network Analysis (WGCNA) was used to identify important modules and hub genes. In addition, correlation analysis between DNA methylation genes and DEGs was performed. Thirdly, the GSE45670 dataset was used to validate the expression of the diagnostic and survival ability analysis of genes in TCGA data. Finally, reverse transcription-quantitative PCR and immunohistochemical analysis of genes were performed.

Results

A total of 2408 DEGs and 5134 differentially methylated sites were obtained. In the WGCNA analysis, the royal blue module was found to be the optimal module. In addition, hub genes in the module, including ESRRG, MFSD4, CCKBR, ATP4B, ESRRB, ATP4A, CCKAR and B3GAT1, were also differentially methylated genes and DEGs. It was found that CCKAR, MFSD4 and ESRRG may be diagnostic gene biomarkers for esophageal carcinoma. In addition, the high expression of MFSD4 was significantly correlated with patient survival. Immunohistochemistry analysis results showed that the gene expression levels of ATP4B, B3GAT1, CCKBR and ESRRG were decreased in esophageal carcinoma tissues, which was in line with the bioinformatics results.

Conclusion

Therefore, these identified molecular markers may be helpful in the diagnosis and treatment of esophageal carcinoma.

Significance of SYT8 For the Detection, Prediction, and Treatment of Peritoneal Metastasis From Gastric Cancer

OBJECTIVE

To develop novel diagnostic and therapeutic targets specific for peritoneal metastasis of gastric cancer (GC).

BACKGROUND

Advanced GC frequently recurs because of undetected micrometastases even after curative resection. Peritoneal metastasis has been the most frequent recurrent pattern after gastrectomy and is incurable.

METHODS

We conducted a recurrence pattern-specific transcriptome analysis in an independent cohort of 16 patients with stage III GC who underwent curative gastrectomy and adjuvant S-1 for screening candidate molecules specific for peritoneal metastasis of GC. Next, another 340 patients were allocated to discovery and validation sets (1:2) to evaluate the diagnostic and predictive value of the candidate molecule. The results of quantitative reverse-transcription PCR and immunohistochemical analysis were correlated with clinical characteristics and survival. The effects of siRNA-mediated knockdown on phenotype and fluorouracil sensitivity of GC cells were evaluated in vitro, and the therapeutic effects of siRNAs were evaluated using a mouse xenograft model.

RESULTS

Synaptotagmin VIII (SYT8) was identified as a candidate biomarker specific to peritoneal metastasis. In the discovery set, the optimal cut-off of SYT8 expression was established as 0.005. Expression levels of SYT8 mRNA in GC tissues were elevated in the validation set comprising patients with peritoneal recurrence or metastasis. SYT8 levels above the cut-off value were significantly and specifically associated with peritoneal metastasis, and served as an independent prognostic marker for peritoneal recurrence-free survival of patients with stage II/III GC. The survival difference between patients with SYT8 levels above and below the cut-off was associated with patients who received adjuvant chemotherapy. Inhibition of SYT8 expression by GC cells correlated with decreased invasion, migration, and fluorouracil resistance. Intraperitoneal administration of SYT8-siRNA inhibited the growth of peritoneal nodules and prolonged survival of mice engrafted with GC cells.

CONCLUSIONS

SYT8 represents a promising target for the detection, prediction, and treatment of peritoneal metastasis of GC.

Increased Expression of DNAJC12 is Associated with Aggressive Phenotype of Gastric Cancer

BACKGROUND

Identification of gastric cancer-related molecules is necessary to elucidate the pathological mechanisms of this heterogeneous disease. The purpose of this study was to identify novel genes associated with aggressive phenotypes of gastric cancer.

METHODS

Global expression profiling was conducted using tissues from four patients with metastatic gastric cancer to identify genes overexpressed in gastric cancer. Fifteen gastric cell lines and 262 pairs of surgically resected gastric tissues were subjected to mRNA expression analysis. The contribution of the candidate gene on gastric cancer cell proliferation, invasion, adhesion, and migration were evaluated using small interfering RNA.

RESULTS

DnaJ heat shock protein family (Hsp40) member C12 (DNAJC12) was identified as a candidate gene by transcriptome analysis. In clinical samples, DNAJC12 mRNA levels were higher in gastric cancer tissues compared with normal adjacent tissues. Patients with high DNAJC12 expression showed significantly shorter overall survival in our cohort and in the extra-validation cohort analyzed by a published microarray dataset. High DNAJC12 expression in gastric cancer tissues was significantly associated with lymphatic involvement, infiltrative growth type, lymph node metastasis, and advanced stage and was identified as an independent prognostic factor for overall survival in multivariable analysis. Increased expression of DNAJC12 was found in 12 of 14 examined gastric cancer cell lines. Knockdown of DNAJC12 expression significantly decreased the proliferation and invasion abilities of gastric cancer cells.

CONCLUSIONS

Our findings support DNAJC12 as a candidate gene associated with aggressive phenotypes of gastric cancer.

Bioinformatics-based analysis reveals elevated MFSD12 as a key promoter of cell proliferation and a potential therapeutic target in melanoma

Although recent therapeutic advances based on our understanding of molecular phenomena have prolonged the survival of melanoma patients, the prognosis of melanoma remains dismal and further understanding of the underlying mechanism of melanoma progression is needed. In this study, differential expression analyses revealed that many genes, including AKT1 and CDK2, play important roles in melanoma. Functional analyses of differentially expressed genes (DEGs), obtained from the GEO (Gene Expression Omnibus) database, indicated that high proliferative and metastatic abilities are the main characteristics of melanoma and that the PI3K and MAPK pathways play essential roles in melanoma progression. Among these DEGs, major facilitator superfamily domain-containing 12 (MFSD12) was found to have significantly and specifically upregulated expression in melanoma, and elevated MFSD12 level promoted cell proliferation by promoting cell cycle progression. Mechanistically, MFSD12 upregulation was found to activate PI3K signaling, and a PI3K inhibitor reversed the increase in cell proliferation endowed by MFSD12 upregulation. Clinically, high MFSD12 expression was positively associated with shorter overall survival (OS) and disease-free survival (DFS) in melanoma patients, and MFSD12 was an independent prognostic factor for OS and DFS in melanoma patients. Therapeutically, in vivo assays further confirmed that MFSD12 interference inhibited tumor growth and lung metastasis in melanoma. In conclusion, elevated MFSD12 expression promotes melanoma cell proliferation, and MFSD12 is a valuable prognostic biomarker and promising therapeutic target in melanoma.

MFSD2A expression predicts better prognosis in gastric cancer

Major facilitator superfamily domain containing-2A (MFSD2A) is reported to correlated with some tumors, but its clinical significance in gastric cancer (GC) is still unknown. The expression of MFSD2A and CD34 were examined on tissue microarrays of 170 set of GC and adjacent normal tissue (ANT) by immunohistochemistry. The relationship of MFSD2A with microvessel density (MVD) and clinicopathological characteristics was also investigated. MFSD2A expression is lower in GC tissue (35.3%) than in ANT (78.2%, P < 0.01). Mean MVD was higher in cancer tissue (49.7 ± 5.46) than in ANT (19.3 ± 2.19, P < 0.01), and higher in MFSD2A^- GC (56.5 ± 7.27), than in MFSD2A⁺ GC (24.8 ± 4.31, P < 0.01). MFSD2A expression was significantly higher in moderately/well differentiated GC (47.4%) than in poorly differentiated GC (25.0%, P < 0.01) and in early-stage GC (46.4%) than in advanced GC (27.7%, P = 0.012). Patients with MFSD2A⁺ specimens (n = 60) had significantly better prognoses than the MFSD2A^- group (n = 110; P < 0.0001). These results suggest that MFSD2A might affect angiogenesis and inhibit GC development and progression. MFSD2A may help predict prognosis and could be a therapeutic target in GC.

Expression of sushi domain containing two reflects the malignant potential of gastric cancer

Hepatic recurrence of gastric cancer (GC) is uncontrollable. Discovery of causative oncogenes and the development of sensitive biomarkers to predict hepatic recurrence are required to improve patients’ outcomes. In this study, recurrence pattern‐specific transcriptome analysis of 57 749 genes was conducted to identify mRNAs specifically associated with hepatic metastasis of patients with stage III GC who underwent curative resection. GC cell lines were subjected to mRNA expression analysis, PCR array analysis, and siRNA‐mediated knockdown. The expression levels of primary cancer tissues from 154 patients with resectable GC were determined and correlated with clinicopathological variables. Among 21 genes significantly overexpressed specifically in patients with hepatic recurrence, Sushi domain containing 2 (SUSD2) was selected as a promising target. PCR array analysis revealed that SUSD2 mRNA levels positively correlated with those of FZD7, CDH2, TGFB1, SPARC, ITGA5, and ZEB1. Functional analysis revealed that knockdown of SUSD2 significantly reduced the proliferation, migration, and invasiveness GC cell lines. Patients with high SUSD2 expression were more likely to experience shorter disease‐free and overall survival. Analysis of the relation between disease recurrence pattern and SUSD2 levels revealed that significantly more patients with hepatic metastases expressed higher levels of SUSD2 mRNA. The cumulative incidence of hepatic recurrence was greater in patients with high SUSD2 expression. In conclusion, SUSD2 likely contributes to the malignant potential of GC and may serve as a novel biomarker that predicts hepatic recurrence after curative resection.

Review of recent efforts to discover biomarkers for early detection, monitoring, prognosis, and prediction of treatment responses of patients with gastric cancer

Gastric cancer (GC) is the leading cause of cancer-related death worldwide. Despite recent advances in diagnosis and therapy, the prognosis of patients with GC is poor. Many patients have inoperable disease upon diagnosis or experience recurrent disease after curative gastrectomy. Unfortunately, tumor markers for GC, such as serum carcinoembryonic antigen and carbohydrate antigen 19-9, lack sufficient sensitivity and specificity. Therefore, effective biomarkers are required to detect early GC and to predict tumor recurrence and chemosensitivity. Areas covered: Here we aimed to review recent developments in techniques that improve the detection of aberrant expression of GC-associated molecules, including protein coding genes, microRNAs, long noncoding RNAs, and methylated promoter DNAs. Expert commentary: Detection of genetic and epigenetic alterations in gastric tissue or in the circulation will likely improve the diagnosis and management of GC to achieve significantly improved outcomes.

Emerging evidence of the molecular landscape specific for hematogenous metastasis from gastric cancer

Gastric cancer (GC) is one of the most frequently diagnosed cancers in the world. Most GC patients are diagnosed when the cancer is in an advanced stage, and consequently, some develop metastatic lesions that generally cause cancer-related death. Metastasis establishment is affected by various conditions, such as tumor location, hemodynamics and organotropism. While digestive cancers may share a primary site, certain cases develop hematogenous metastasis with the absence of peritoneal metastasis, and vice versa. Numerous studies have revealed the clinicopathological risk factors for hematogenous metastasis from GC, such as vascular invasion, advanced age, differentiation, Borrmann type 1 or 2 and expansive growth. Recently, molecular mechanisms that contribute to metastatic site determination have been elucidated by advanced molecular biological techniques. Investigating the molecules that specifically participate in metastasis establishment in distinct secondary organs will lead to the development of novel biomarkers for patient stratification according to their metastatic risk and strategies for preventing and treating distinct metastases. We reviewed articles related to the molecular landscape of hematogenous metastasis from GC.

SYT7 acts as a driver of hepatic metastasis formation of gastric cancer cells

Liver metastasis remains a serious problem in the management of gastric cancer (GC). Our aims were to identify through transcriptome analysis a molecule that mediates hepatic metastasis in GC, and to evaluate its potential as a diagnostic marker and a therapeutic target. The effects of knocking out a relevant molecule using genome editing were evaluated in vitro experiments and in mouse xenograft models. Expression levels of candidate molecule in 300 pairs of gastric tissues were determined to assess whether differentially expressed genes predicted hepatic recurrence, metastasis, or both. Transcriptome data identified the overexpression of synaptotagmin VII (SYT7) in GC tissues with hepatic metastasis. Its expression in the GC cell lines was high, particularly in those that exhibited a differentiated phenotype, and positively correlated with the expression of SNAI1 and TGFB3, and inversely with RGS2. SYT7 knockout inhibited the proliferation of GC cells, indicated by increased apoptosis with activated caspase and loss of mitochondria membrane potential, G2/M cell-cycle arrest and attenuated cell migration, invasion, and adhesion. The tumorigenicity of SYT7-knockout cells was moderately reduced in a mouse model of subcutaneous metastasis in which the levels of BCL2 and HIF1A were decreased and was more strikingly attenuated in a model of hepatic metastasis. The SYT7 levels in the primary GC tissues were significantly associated with hepatic recurrence, metastasis, and adverse prognosis. SYT7 represents a tool for prediction and monitoring of hepatic metastasis from GC as well as being a promising therapeutic target.

Linc00483 as ceRNA regulates proliferation and apoptosis through activating MAPKs in gastric cancer

Long non‐coding RNAs (lncRNAs) are important regulators of many cellular processes, and their aberrant expression and/or function is associated with many different diseases, including cancer. However, the identification of functional lncRNAs in gastric cancer is still a challenge. In this study, we describe a novel functional lncRNA, linc00483, that is upregulated and associated with tumorigenesis, tumour size, metastasis and poor prognosis in gastric cancer. In our study, linc00483 promoted gastric cancer cell proliferation, invasiveness and metastasis in vitro and in vivo. Mechanistically, upregulated expression of linc00483 in gastric cancer acts as a sponge to absorb endogenous tumour suppressor miR‐30a‐3p. Furthermore, it restores SPAG9 expression, which is negatively regulated by miR‐30a‐3p, and actives MAPK signaling pathway in gastric cancer cells. Thus, linc00483 is an oncogenic lncRNA in gastric cancer and targeting linc00483 or its pathway can potentially be useful in development of targeted therapies for patients with gastric cancer. Our results show that linc00483 is an important regulator in carcinogenesis and may be a useful biomarker to predict prognosis of gastric cancer patients. We believe our findings are novel and will be of interest to scientists working in many areas related to biomarkers in cancer.

A novel dual-marker expression panel for easy and accurate risk stratification of patients with gastric cancer

Development of specific biomarkers is necessary for individualized management of patients with gastric cancer. The aim of this study was to design a simple expression panel comprising novel molecular markers for precise risk stratification. Patients (n = 200) who underwent gastrectomy for gastric cancer were randomly assigned into learning and validation sets. Tissue mRNA expression levels of 15 candidate molecular markers were determined using quantitative PCR analysis. A dual‐marker expression panel was created according to concordance index (C‐index) values of overall survival for all 105 combinations of two markers in the learning set. The reproducibility and clinical significance of the dual‐marker expression panel were evaluated in the validation set. The patient characteristics of the learning and validation sets were well balanced. The C‐index values of combinations were significantly higher compared with those of single markers. The panel with the highest C‐index (0.718) of the learning set comprised SYT8 and MAGED2, which clearly stratified patients into low‐, intermediate‐, and high‐risk groups. The reproducibility of the panel was demonstrated in the validation set. High expression scores were significantly associated with larger tumor size, vascular invasion, lymph node metastasis, peritoneal metastasis, and advanced disease. The dual‐marker expression panel provides a simple tool that clearly stratifies patients with gastric cancer into low‐, intermediate‐, and high risk after gastrectomy.

Troponin I2 as a Specific Biomarker for Prediction of Peritoneal Metastasis in Gastric Cancer

BACKGROUND

Although peritoneal metastasis is a serious concern in patients with gastric cancer, no acceptable and specific biomarker is available. We aimed to identify a candidate biomarker to predict peritoneal metastasis of gastric cancer.

METHODS

Metastatic pathway-specific transcriptome analysis was conducted by comparison of patient groups with no recurrence and with peritoneal, hepatic, and nodal recurrence. Fifteen cell lines and 262 pairs of surgically resected gastric tissues were subjected to messenger RNA (mRNA) expression analysis. Polymerase chain reaction array analysis was performed to explore coordinately expressed cancer-related genes. To evaluate the in situ protein localization and expression patterns, immunohistochemical staining was performed.

RESULTS

From transcriptome data, troponin I2 (TNNI2) was identified as a candidate molecule specifically overexpressed in gastric cancer prone to peritoneal metastasis. TNNI2 mRNA was expressed at differential levels, independent of differentiated phenotype of cell lines. Epithelial to mesenchymal transition-related genes, tumor inhibitor of metalloproteinase 1 (TIMP1), and vacuolar protein sorting 13 homolog A (VPS13A) were expressed with TNNI2 at correlation coefficient > 0.7. The optimal cutoff of TNNI2 expression was determined as 0.00017. High TNNI2 expression was significantly and specifically associated with peritoneal metastasis and served as an independent risk marker for peritoneal recurrence after curative gastrectomy. Prevalence of peritoneal recurrence increased in parallel with staining intensity of TNNI2.

CONCLUSIONS

TNNI2 expression in gastric tissues may serve as a specific biomarker for prediction of peritoneal metastasis of gastric cancer and contribute to improvement of patient management.

Structural biology of solute carrier (SLC) membrane transport proteins

The human solute carriers (SLCs) comprise over 400 different transporters, organized into 65 families ( http://slc.bioparadigms.org/ ) based on their sequence homology and transport function. SLCs are responsible for transporting extraordinarily diverse solutes across biological membranes, including inorganic ions, amino acids, lipids, sugars, neurotransmitters and drugs. Most of these membrane proteins function as coupled symporters (co-transporters) utilizing downhill ion (H⁺ or Na⁺) gradients as the driving force for the transport of substrate against its concentration gradient into cells. Other members work as antiporters (exchangers) that typically contain a single substrate-binding site with an alternating access mode of transport, while a few members exhibit channel-like properties. Dysfunction of SLCs is correlated with numerous human diseases and therefore they are potential therapeutic drug targets. In this review, we identified all of the SLC crystal structures that have been determined, most of which are from prokaryotic species. We further sorted all the SLC structures into four main groups with different protein folds and further discuss the well-characterized MFS (major facilitator superfamily) and LeuT (leucine transporter) folds. This review provides a systematic analysis of the structure, molecular basis of substrate recognition and mechanism of action in different SLC family members.

Integrated multigene expression panel to prognosticate patients with gastric cancer

Most of the proposed individual markers had limited clinical utility due to the inherent biological and genetic heterogeneity of gastric cancer. We aimed to build a new molecular-based model to predict prognosis in patients with gastric cancer. A total of 200 patients who underwent gastric resection for gastric cancer were divided into learning and validation cohorts using a table of random numbers in a 1:1 ratio. In the learning cohort, mRNA expression levels of 15 molecular markers in gastric tissues were analyzed and concordance index (C-index) values of all single and combinations of the 15 candidate markers for overall survival were calculated. The multigene expression panel was designed according to C-index values and the subpopulation index. Expression scores were determined with weighting according to the coefficient of each constituent. The reproducibility of the panel was evaluated in the validation cohort. C-index values of the 15 single candidate markers ranged from 0.506–0.653. Among 32,767 combinations, the optimal and balanced expression panel comprised four constituents (MAGED2, SYT8, BTG1, and FAM46) and the C-index value was 0.793. Using this panel, patients were provisionally categorized with scores of 1–3, and clearly stratified into favorable, intermediate, and poor overall survival groups. In the validation cohort, both overall and disease-free survival rates decreased incrementally with increasing expression scores. Multivariate analysis revealed that the expression score was an independent prognostic factor for overall survival after curative gastrectomy. We developed an integrated multigene expression panel that simply and accurately stratified risk of patients with gastric cancer.

A pan-cancer analysis of MYC-PVT1 reveals CNV-unmediated deregulation and poor prognosis in renal carcinoma

The PVT1 lncRNA has recently been involved in tumorigenesis by affecting the protein stability of the MYC proto-oncogene. Both MYC and PVT1 reside in a well-known cancer-risk locus and enhanced levels of their products have been reported in different human cancers. Nonetheless, the extension and relevance of the MYC-PVT1 deregulation in tumorigenesis has not yet been systematically addressed.

Here we performed a pan-cancer analysis of matched copy number, transcriptomic, methylation, proteomic and clinicopathological profiles for almost 7000 patients from 17 different cancers represented in the TCGA cohorts. Among all cancers types, kidney renal clear cell carcinoma (KIRC) showed the strongest upregulation of PVT1 and increased levels of both MYC and PVT1 correlated with the clinical outcome. PVT1 misregulation in KIRC is mostly associated to promoter hypomethylation rather than locus amplification. Furthermore, we found an association between MYC levels and PVT1 expression, which impacted on MYC-target genes.

Collectively, our study discloses the role of PVT1 as a novel prognostic factor and as a molecular target for novel therapeutic interventions in renal carcinoma.

Structural prediction of two novel human atypical SLC transporters, MFSD4A and MFSD9, and their neuroanatomical distribution in mice

Out of the 430 known solute carriers (SLC) in humans, 30% are still orphan transporters regarding structure, distribution or function. Approximately one third of all SLCs belong to the evolutionary conserved and functionally diverse Major Facilitator Superfamily (MFS). Here, we studied the orphan proteins, MFSD4A and MFSD9, which are atypical SLCs of MFS type. Hidden Markov Models were used to identify orthologues in several vertebrates, and human MFSD4A and MFSD9 share high sequence identity with their identified orthologues. MFSD4A and MFSD9 also shared more than 20% sequence identity with other phylogenetically related SLC and MFSD proteins, allowing new family clustering. Homology models displayed 12 transmembrane segments for both proteins, which were predicted to fold into a transporter-shaped structure. Furthermore, we analysed the location of MFSD4A and MFSD9 in adult mouse brain using immunohistochemistry, showing abundant neuronal protein staining. As MFSD4A and MFSD9 are plausible transporters expressed in food regulatory brain areas, we monitored transcriptional changes in several mouse brain areas after 24 hours food-deprivation and eight weeks of high-fat diet, showing that both genes were affected by altered food intake in vivo. In conclusion, we propose MFSD4A and MFSD9 to be novel transporters, belonging to disparate SLC families. Both proteins were located to neurons in mouse brain, and their mRNA expression levels were affected by the diet.

Mouse Nudt13 is a Mitochondrial Nudix Hydrolase with NAD(P)H Pyrophosphohydrolase Activity

The mammalian NUDT13 protein possesses a sequence motif characteristic of the NADH pyrophosphohydrolase subfamily of Nudix hydrolases. Due to the persistent insolubility of the recombinant product expressed in Escherichia coli, active mouse Nudt13 was expressed in insect cells from a baculovirus vector as a histidine-tagged recombinant protein. In vitro, it efficiently hydrolysed NADH to NMNH and AMP and NADPH to NMNH and 2',5'-ADP and had a marked preference for the reduced pyridine nucleotides. Much lower activity was obtained with other nucleotide substrates tested. K m and k cat values for NADH were 0.34 mM and 7 s-1 respectively. Expression of Nudt13 as an N-terminal fusion to green fluorescent protein revealed that it was targeted exclusively to mitochondria by the N-terminal targeting peptide, suggesting that Nudt13 may act to regulate the concentration of mitochondrial reduced pyridine nucleotide cofactors and the NAD(P)+/NAD(P)H ratio in this organelle and elsewhere. Future studies of the enzymology of pyridine nucleotide metabolism in relation to energy homeostasis, redox control, free radical production and cellular integrity should consider the possible regulatory role of Nudt13.

Downregulation of GPR155 as a prognostic factor after curative resection of hepatocellular carcinoma

Background

Molecular biomarkers capable of predicting recurrence patterns and prognosis are helpful for risk stratification and providing appropriate treatment to patients with hepatocellular carcinoma (HCC). In this study, we focused on G protein-coupled receptor 155 (GPR155), a cell surface signaling protein, as a candidate biomarker.

Methods

We analyzed GPR155 expression, DNA methylation, and copy number in HCC cell lines. The clinical significance of GPR155 expression was evaluated using 144 pairs of surgically resected liver and normal tissues with subgroup analysis based on hepatitis virus infection.

Results

GPR155 mRNA expression levels were differential and were decreased in 89% of HCC cell lines. No DNA methylation was detected, whereas copy number alterations were present in five (56%) HCC cell lines. GPR155 mRNA expression level was independent of background liver status and significantly lower in HCC tissues than corresponding normal liver tissues. The expression patterns of GPR155 protein by immunohistochemical staining were significantly associated with those of GPR155 mRNA. Downregulation of GPR155 was significantly associated with more aggressive HCC phenotypes including high preoperative α-fetoprotein, poor differentiation, serosal infiltration, vascular invasion, and advanced disease stage. Patients with downregulation of GPR155 were more likely to have worse prognosis after curative resection irrespective of hepatitis virus infection. Patients who experienced extrahepatic (distant) recurrences had significantly lower GPR155 expression than those with intrahepatic (liver confined) recurrences.

Conclusions

Downregulation of GPR155 may serve as a prognosticator that also predicts initial recurrence sites independent of hepatitis virus infection.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3629-2) contains supplementary material, which is available to authorized users.

Identification of NCCRP1 as an epigenetically regulated tumor suppressor and biomarker for malignant phenotypes of squamous cell carcinoma of the esophagus

The poor prognosis and increasing incidence of esophageal squamous cell carcinoma (ESCC) highlight the need for identification of novel ESCC-associated molecular events to improve the diagnosis, and treatment of this disease. Non-specific cytotoxic cell receptor protein 1 (NCCRP1) was reported to be abundantly expressed in human squamous epithelium and to be involved in cell proliferation; however, the role of NCCRP1 in ESCC remains unclear. To elucidate the oncological roles of NCCRP1 in ESCC, NCCRP1 expression, DNA methylation, and copy numbers were analyzed in ESCC cell lines. Nine ESCC cell lines demonstrated different NCCRP1 mRNA expression levels and all exhibited hypermethylation of the NCCRP1 promoter, but no copy number loss. Additionally, NCCRP1 expression was determined in 213 surgically resected esophageal tissue samples. NCCRP1 mRNA expression levels were reduced in ESCC tissues compared with corresponding non-cancerous adjacent tissues in 204 (95.8%) patients. Patients in the low NCCRP1 expression group tended to have a higher recurrence rate and a shorter overall survival time compared with those in the high NCCRP1 expression group. Additionally, multivariate analysis revealed that low NCCRP1 expression was an independent prognostic factor (hazard ratio, 1.75; 95% confidence interval, 1.08-2.87; P=0.022). The findings of the current study indicate that NCCRP1 acts as a putative tumor suppressor that is inactivated through promoter hypermethylation, and serves as a promising biomarker to predict postoperative prognosis in ESCC.

Usefulness of preoperative estimated glomerular filtration rate to predict complications after curative gastrectomy in patients with clinical T2-4 gastric cancer

BACKGROUND

Gastrectomy with systemic lymphadenectomy is the standard of care for resectable gastric cancer (GC), but it is sometimes associated with postoperative morbidity. Predicting complications is therefore an essential part of risk management in clinical practice. The renal function is routinely evaluated before surgery by blood examinations to determine dose of medication and infusion. However, the value of various parameters of renal function in prediction of postoperative complications remain unclear.

METHODS

We included 315 patients who underwent curative D2 gastrectomy for clinical T2-T4 GC without preoperative treatment, and evaluated the correlation between the incidence of postoperative complications and the indicators of renal function.

RESULTS

Forty-three patients experienced clinically relevant postoperative complications. Estimated glomerular filtration rate (eGFR) showed a higher area under the curve for predicting complications compared with urea nitrogen, creatinine, and creatinine clearance. The optimal eGFR cutoff value was 63.2 ml/min/1.73 m², and eGFR < 63.2 was an independent risk factor for postoperative complications in multivariable analysis (odds ratio 4.67; 95 % confidence interval 2.16-10.5; p < 0.001). Particularly, the incidence of anastomotic leakage was significantly higher in patients with eGFR < 63.2 than those with eGFR ≥ 63.2 (9.4 % vs. 3.5 %). eGFR < 63.2 was also associated with a higher incidence of postoperative complications independent of age, body mass index, operative procedure, and clinical disease stage. Postoperative hospital stay was significantly longer in the eGFR < 63.2 group.

CONCLUSIONS

Preoperative eGFR is a simple and useful predictor for complications after gastrectomy in patients with GC and may improve clinical care and the process of obtaining informed consent.

FBXO50 Enhances the Malignant Behavior of Gastric Cancer Cells

BACKGROUND

Challenges to our understanding the molecular mechanisms of the progression of gastric cancer (GC) must be overcome to facilitate the identification of novel biomarkers and therapeutic targets. In this article, we analyzed the expression of the gene encoding F-box-only 50 (FBXO50) and determined whether it contributes to the malignant phenotype of GC.

METHODS

FBXO50 messenger RNA (mRNA) levels and copy numbers of the FBXO50 locus were determined in 10 GC cell lines and a nontumorigenic epithelial cell line. Polymerase chain reaction array analysis was performed to identify genes coordinately expressed with FBXO50. The effects of inhibiting FBXO50 on GC cell proliferation, adhesion, invasiveness, and migration were evaluated using a small interfering RNA targeted to FBXO50 mRNA. To evaluate the clinical significance of FBXO50 expression, we determined the levels of FBXO50 mRNA in tissues acquired from 200 patients with GC.

RESULTS

The levels of FBXO50 mRNA were increased in five GC cell lines and positively correlated with those of ITGA5, ITGB1, MMP2, MSN, COL5A2, GNG11, and WNT5A. Copy number gain of the FBXO50 locus was detected in four GC cell lines. Inhibition of FBXO50 expression significantly decreased the proliferation, adhesion, migration, and invasiveness of GC cell lines. In clinical samples, high FBXO50 expression correlated with increased pT4, invasive growth, lymph node metastasis, and positive peritoneal lavage cytology. Patients with high FBXO50 expression had a significantly higher prevalence of recurrence after curative gastrectomy and were more likely to experience shorter overall survival.

CONCLUSIONS

FBXO50 may represent a biomarker for GC phenotypes and as a target for therapy.

Expression of regulatory factor X1 can predict the prognosis of breast cancer

Breast cancer (BC) is the most common malignancy among women. Identifying novel biomarkers to predict prognosis accurately is important in managing this disease. The regulatory factor X1 (RFX1) gene is a member of the regulatory factor X gene family. Its protein reportedly downregulates the proto-oncogene c-myc, but its role in BC has been unclear. In this study, expression and methylation status of RFX1 were determined in BC cell lines. We then evaluated RFX1 mRNA expression levels with regard to clinicopathological factors including postoperative prognosis in 167 patients with BC. Expression of RFX1 was heterogeneous among cell lines, and we found no DNA methylation at the RFX1 promoter region. Patients were categorized into groups with high or low RFX1 expression, based on ratio of RFX1 mRNA expression in BC and adjacent non-cancerous tissues. The high RFX1 group was significantly associated with low T factor (P=0.028), earlier disease stage (P=0.015), positive expression of estrogen receptor (P=0.005) and progesterone receptor (P=0.011), negative expression of human epidermal growth factor receptor 2 (P=0.001). The high RFX1 group experienced more favorable disease-free survival (P=0.007) and overall survival (P=0.013). In multivariate analysis, RFX1 expression was an independent prognostic factor for disease-free survival. Our findings indicate that RFX1 may serve as a prognostic marker for BC.

GPR155 Serves as a Predictive Biomarker for Hematogenous Metastasis in Patients with Gastric Cancer

The prognosis of patients with gastric cancer (GC) with hematogenous metastasis is dismal. Identification of biomarkers specific for hematogenous metastasis is required to develop personalized treatments that improve patients' outcomes. Global expression profiling of GC tissues with synchronous hepatic metastasis without metastasis to the peritoneal cavity or distant lymph nodes was conducted using next-generation sequencing and identified the G protein-coupled receptor 155 (GPR155) as a candidate biomarker. GPR155 transcription was suppressed in GC cell lines compared with a nontumorigenic cell line. DNA methylation of the GPR155 promoter region was not detected, albeit 20% of GC cell lines harbored copy number loss at GPR155 locus. The expression levels of GPR155 mRNA correlated inversely with those of TWIST1 and WNT5B. Inhibition of GPR155 expression increased the levels of p-ERK1/2 and p-STAT1, significantly increased cell proliferation, and increased the invasiveness of a GC cell lines. GPR155 mRNA levels in GC clinical samples correlated with hematogenous metastasis and recurrence. Multivariate analysis revealed that reduced expression of GPR155 mRNA was an independent predictive marker of hematogenous metastasis. GPR155 may represent a biomarker for diagnosing and predicting hematogenous metastasis of GC.

Pharmacokinetic dose adjustment of 5-FU in modified FOLFOX7 plus bevacizumab for metastatic colorectal cancer in Japanese patients: a-JUST phase II clinical trial

PURPOSE

Dose adjustment of 5-fluorouracil (FU) based on pharmacokinetic monitoring has been shown to reduce toxicities and increase efficacy compared with dosing based on body surface area in patients with metastatic colorectal cancer (mCRC). We evaluated the efficacy and safety of pharmacokinetic dose adjustment of FU in a modified FOLFOX7 (mFOLFOX7) plus bevacizumab regimen in Japanese patients with previously untreated mCRC.

METHODS

This single-arm, multicenter phase II trial enrolled 48 patients with mCRC. Treatment consisted of 5 mg/kg intravenous bevacizumab followed by mFOLFOX7 (oxaliplatin 85 mg/m² on day 1, infused leucovorin 200 mg/m², followed by a 2400 mg/m² infusion of FU for 46 h starting on day 1), repeated every 2 weeks. FU concentrations were measured by immunoassay between 18 and 36 h after the start of continuous FU infusion, and the FU dose was then adjusted if required in subsequent cycles. The primary endpoint was response rate.

RESULTS

The median initial area under the concentration-time curve for FU was 23 mg h/L. Twenty-nine patients (60%) achieved the target concentration at the first cycle, and all 48 achieved it within the fourth cycle. The overall frequency of grade 3/4 adverse effects was 38%, with no significant difference between patients who did and not require dose adjustments. The overall response rate was 48% (95% confidence intervals = 34-62%). The median progression-free and overall survival rates were 11.3 and 24.1 months, respectively.

CONCLUSIONS

Pharmacokinetic dose adjustment of FU in mFOLFOX7 plus bevacizumab can optimize FU concentrations promptly and is safe in Japanese patients with mCRC.

Expressed microRNA associated with high rate of egg production in chicken ovarian follicles

MicroRNA (miRNA) is a highly conserved class of small noncoding RNA about 19-24 nucleotides in length that function in a specific manner to post-transcriptionally regulate gene expression in organisms. Tissue miRNA expression studies have discovered a myriad of functions for miRNAs in various aspects, but a role for miRNAs in chicken ovarian tissue at 300 days of age has not hitherto been reported. In this study, we performed the first miRNA analysis of ovarian tissues in chickens with low and high rates of egg production using high-throughput sequencing. By comparing low rate of egg production chickens with high rate of egg production chickens, 17 significantly differentially expressed miRNAs were found (P < 0.05), including 11 known and six novel miRNAs. We found that all 11 known miRNAs were involved mainly in pathways of reproduction regulation, such as steroid hormone biosynthesis and dopaminergic synapse. Additionally, expression profiling of six randomly selected differentially regulated miRNAs were validated by quantitative real-time polymerase chain reaction (RT-qPCR). Some miRNAs, such as gga-miR-34b, gga-miR-34c and gga-miR-216b, were reported to regulate processes such as proliferation, cell cycle, apoptosis and metastasis and were expressed differentially in ovaries of chickens with high rates of egg production, suggesting that these miRNAs have an important role in ovary development and reproductive management of chicken. Furthermore, we uncovered that a significantly up-regulated miRNA-gga-miR-200a-3p-is ubiquitous in reproduction-regulation-related pathways. This miRNA may play a special central role in the reproductive management of chicken, and needs to be further studied for confirmation.

FAM46C Serves as a Predictor of Hepatic Recurrence in Patients with Resectable Gastric Cancer

BACKGROUND

Gastric cancer (GC) relapse can occur even if curative resection is achieved. Biomarkers predicting recurrence are needed to provide appropriate postoperative surveillance and perioperative therapeutic strategy.

METHODS

A global expression profiling was performed using tissues from GC patients with synchronous liver-confined metastasis. Family with sequence similarity 46, member C (FAM46C), was identified as a candidate biomarker. mRNA expression analysis, direct nucleotide sequencing, bisulfite sequencing and copy number assays for FAM46C were performed with eleven GC cell lines. Expression levels of FAM46C in primary GC tissues from 129 patients who underwent curative GC resection were determined and correlated with clinicopathological factors, including postoperative outcome.

RESULTS

Levels of FAM46C mRNA differed among GC cell lines. Point mutations in FAM46C were detected in five GC cell lines accompanied with reduced FAM46C transcription. No hypermethylation was found in the promoter region of FAM46C. Copy number alterations were found in six GC cell lines with differing FAM46C transcription levels. Reduced FAM46C mRNA expression levels were detected in 117 (91 %) GC specimens compared with adjacent noncancerous tissues. Low FAM46C expression levels were significantly associated with larger macroscopic GC tumor sizes. The low FAM46C expression group was likely to have shorter disease-free survival than the high group and low FAM46C level was identified as an independent risk factor for recurrence after curative resection. FAM46C expression levels were low in all cases that were later found to have hepatic recurrence.

CONCLUSIONS

Reduced GC expression of FAM46C is a potential biomarker to predict hepatic recurrence after curative gastrectomy.

Prognostic relevance of SAMSN1 expression in gastric cancer

The prognosis for patients with advanced gastric cancer (GC) remains poor. The identification of biomarkers relevant to the recurrence and metastasis of GC is advantageous for stratifying patients and proposing novel molecular targets. In the present study the oncological roles of SAM domain, SH3 domain and nuclear localization signals 1 (SAMSN1), a mediator of B-cell function, were elucidated in GC. The expression and methylation status of SAMSN1 were investigated in a panel of 11 GC cell lines. Immunohistochemical staining was performed to determine the pattern of SAMSN1 protein expression in gastric tissues. The prognostic impact of SAMSN1 expression was determined by analyzing 175 pairs of surgically resected gastric tissues. A marked decrease in the level of SAMSN1 mRNA was detected in 8/11 GC cell lines as compared with that in a non-transformed intestinal epithelium cell line (FHs 74) without promoter methylation. The mean expression level of SAMSN1 mRNA was reduced in GC tissues compared with normal adjacent tissues, an observation that was independent of tumor differentiation. The pattern of SAMSN1 protein expression was significantly correlated with that of SAMSN1 mRNA. Low SAMSN1 mRNA expression was significantly associated with tumor size (>60 mm; P=0.026) and shorter overall survival times (P=0.004). Multivariate analysis identified low SAMSN1 mRNA expression as an independent prognostic factor for poor overall survival (hazard ratio, 1.80; 95% confidence interval, 1.07-3.05; P=0.025). The difference in survival between the low and high SAMSN1 expression groups was more marked in patients with stage II/III GC compared to those with stage IV GC. In patients with stage II/III GC who underwent curative surgery, low SAMSN1 expression was associated with reduced disease free survival times. The results of the present study indicate that downregulation of SAMSN1 transcription may affect the progression and recurrence of GC, and therefore may represent a novel biomarker of GC.

The COMET Open-label Phase II Study of Neoadjuvant FOLFOX or XELOX Treatment Combined with Molecular Targeting Monoclonal Antibodies in Patients with Resectable Liver Metastasis of Colorectal Cancer

BACKGROUND

Advantages of neoadjuvant chemotherapy combined with monoclonal antibodies for treating patients with resectable colorectal cancer liver metastasis (CLM) have not been established. The purpose of this study was to evaluate the efficacy and safety of oxaliplatin-based regimen (FOLFOX or XELOX) plus monoclonal antibodies (cetuximab or bevacizumab) treatment in patients with resectable CLM.

METHODS

A single-arm, open-label, multicenter, phase II trial was conducted for patients aged ≥ 20 years with resectable and untreated CLM. Patients received preoperative FOLFOX (6 cycles) or XELOX (4 cycles). Cetuximab or bevacizumab was administered to patients with wild-type or mutated KRAS codons 12 and 13, respectively. The primary endpoint was progression-free survival (PFS).

RESULTS

Between January 2010 and June 2012, 47 patients were enrolled from 12 institutions. Wild-type or mutant KRAS sequences were examined in 32 and 15 patients, respectively. Twenty-one (45 %) patients experienced Grades 3/4 adverse events, and 55 % of all patients responded to therapy. The sizes of tumors of patients in the wild-type KRAS group were significantly reduced compared with those of the mutant KRAS group. The overall rates of liver resection and postoperative morbidity were 83 and 14 %, respectively, and the median PFS was 15.6 months. The median PFS times of the KRAS wild-type and mutant groups were 22.5 months and 10.5 months, respectively.

CONCLUSIONS

Neoadjuvant therapy using FOLFOX/XELOX combined with monoclonal antibodies did not improve PFS, although it was administered safely and had less adverse effects after liver resection.

Proposal of the Coagulation Score as a Predictor for Short-Term and Long-Term Outcomes of Patients with Resectable Gastric Cancer

BACKGROUND

Systemic hemostasis and thrombosis activation has been implicated in tumor progression and metastasis. This study aimed to investigate the use of coagulation factors as a novel prediction method for postoperative outcomes after curative gastrectomy in patients with stage II/III gastric cancer (GC).

METHODS

Overall, 126 patients with stage II/III GC who underwent gastrectomy between May 2003 and February 2016 were eligible for inclusion in the study. We retrospectively evaluated the predictive value of preoperative platelet count and plasma fibrinogen and d-dimer levels, and coagulation score (0: fibrinogen and d-dimer both below upper limits; 1: either fibrinogen or d-dimer over upper limits; 2: both fibrinogen and d-dimer over upper limits) for short- and long-term outcomes.

RESULTS

Postoperative complications were significantly more frequent in patients with elevated preoperative d-dimer levels compared with those with normal d-dimer levels (26 vs. 10 %; p = 0.032). The prevalence of postoperative complications showed a stepwise increase in proportion to the coagulation score. Patients with a coagulation score of 2 had significantly larger tumors (p = 0.013) and significantly greater intraoperative blood loss (p = 0.004) than those who scored 0 or 1. Coagulation score showed the highest values distinguished high-risk patients in overall and disease-free survival, and a coagulation score of 2 was an independent prognostic factor for recurrence. Patients with a coagulation score of 2 experienced a significantly higher prevalence of liver metastasis as an initial recurrence than those who scored 0 or 1 (p = 0.019).

CONCLUSIONS

The coagulation score is a simple and promising predictor for postoperative complications and recurrence after gastrectomy in stage II/III GC patients.

Molecular mechanisms of peritoneal dissemination in gastric cancer

Peritoneal dissemination represents a devastating form of gastric cancer (GC) progression with a dismal prognosis. There is no effective therapy for this condition. The 5-year survival rate of patients with peritoneal dissemination is 2%, even including patients with only microscopic free cancer cells without macroscopic peritoneal nodules. The mechanism of peritoneal dissemination of GC involves several steps: detachment of cancer cells from the primary tumor, survival in the free abdominal cavity, attachment to the distant peritoneum, invasion into the subperitoneal space and proliferation with angiogenesis. These steps are not mutually exclusive, and combinations of different molecular mechanisms can occur in each process of peritoneal dissemination. A comprehensive understanding of the molecular events involved in peritoneal dissemination is important and should be systematically pursued. It is crucial to identify novel strategies for the prevention of this condition and for identification of markers of prognosis and the development of molecular-targeted therapies. In this review, we provide an overview of recently published articles addressing the molecular mechanisms of peritoneal dissemination of GC to provide an update on what is currently known in this field and to propose novel promising candidates for use in diagnosis and as therapeutic targets.

Epigenetic suppression of the immunoregulator MZB1 is associated with the malignant phenotype of gastric cancer

Prediction of tumor recurrence after curative resection is critical for determining the prognosis of patients with gastric cancer (GC). The initiation and progression of GC are associated with inappropriate immune responses caused by chronic inflammation of the gastric mucosa. To identify immunoregulatory molecules involved in GC progression, GC cell lines and 200 pairs of tumor and normal tissues from patients with GC were analyzed for gene expression, amplification and methylation as well as function of a differentially expressed gene. The transcriptome analysis revealed that marginal zone B and B1 cell specific protein (MZB1) was expressed at significantly decreased levels in primary GC tissues when compared with the corresponding normal gastric mucosa. PCR array analysis exploring genes expressed cooperatively with MZB1 revealed that differential expression of MZB1 mRNA in GC cell lines correlated positively with the levels of the mRNAs encoding estrogen receptor 1 and desumoylating isopeptidase 1. Hypermethylation of the MZB1 promoter was frequent in cell lines with decreased levels of MZB1 mRNA. siRNA-mediated knockdown of MZB1 significantly increased proliferation, invasion and migration of GC cell lines. Low MZB1 expression was an independent prognostic factor for recurrence after curative gastrectomy and was associated significantly with increased hematogenous recurrence. MZB1 acts as a suppressor of GC. Low MZB1 expression in the primary GC tissue is predictive of recurrence after curative resection.

Neurotrophin Receptor-Interacting Melanoma Antigen-Encoding Gene Homolog is Associated with Malignant Phenotype of Gastric Cancer

BACKGROUND

Identification of novel molecules implicated in the malignancy of gastric cancer (GC) is key to the development of personalized treatments and the improvement of patient outcome. Neurotrophin receptor-interacting melanoma antigen-encoding protein (NRAGE) regulates apoptosis and metastasis via interactions with various genes. This study aimed to evaluate the function and clinical significance of NRAGE in GC.

METHODS

The expression of NRAGE and its putative interacting genes apoptosis antagonizing transcription factor (AATF), p75 neurotrophin receptor (p75NTR), and proliferating cell nuclear antigen (PCNA) were determined in GC cell lines using reverse transcription-polymerase chain reaction (RT-PCR). The effect of NRAGE knockdown by small interfering RNA (siRNA) on GC cell behavior also was evaluated. In addition, NRAGE expression was determined in 179 pairs of resected gastric tissues.

RESULTS

Expression of NRAGE mRNA positively correlated with that of AATF, and NRAGE knockdown significantly decreased the proliferation, migration, and invasion of GC cells. The mean level of NRAGE mRNA expression was significantly higher in GC tissues than in corresponding adjacent normal tissues. The expression patterns of NRAGE mRNA and protein were closely correlated. A stepwise elevation in NRAGE mRNA expression in GC tissues was observed with increasing Union for International Cancer Control (UICC) stage. High NRAGE expression in GCs was associated with shortened recurrence-free survival and identified as an independent prognostic factor (hazard ratio, 1.83; 95 % CI, 1.12-3.02, p = 0.017).

CONCLUSIONS

The results indicate that NRAGE represents a putative oncogene associated with a malignant phenotype of GC. In GC, NRAGE may serve as a predictive biomarker and a target of molecular therapy.

Protein arginine methyltransferase 5 is associated with malignant phenotype and peritoneal metastasis in gastric cancer

Identification of novel gastric cancer (GC)-related molecules is necessary to improve management of patients with GC in both diagnostic and therapeutic aspects. The aim of the present study was to determine whether protein arginine methyltransferase 5 (PRMT5) acts as an oncogene in the progression of GC and whether it serves as a novel diagnostic marker and therapeutic target. We conducted global expression profiling of GC cell lines and RNA interference experiments to evaluate the effect of PRMT5 expression on the phenotype of GC cells. We analysed tissues of 179 patients with GC to assess the association of PRMT5 mRNA levels with clinicopathological factors. Differential expression of PRMT5 mRNA by GC cell lines correlated positively with the levels of GEMIN2, STAT3 and TGFB3. PRMT5 knockdown reduced the proliferation, invasion and migration of a GC cell line. PRMT5 mRNA levels were significantly higher in GC tissues than the corresponding adjacent normal tissues and were independent of tumour depth, differentiation and lymph node metastasis. High PRMT5 expression was an independent risk factor of positive peritoneal lavage cytology (odds ratio 3.90, P=0.003) and decreased survival. PRMT5 enhances the malignant phenotype of GC cell lines and its expression in gastric tissues may serve as a biomarker for patient stratification and a potential target of therapy.

Nutritional predictors for postoperative short-term and long-term outcomes of patients with gastric cancer

Evidence indicates that impaired immunocompetence and nutritional status adversely affect short-term and long-term outcomes of patients with cancer. We aimed to evaluate the clinical significance of preoperative immunocompetence and nutritional status according to Onodera's prognostic nutrition index (PNI) among patients who underwent curative gastrectomy for gastric cancer (GC).This study included 260 patients with stage II/III GC who underwent R0 resection. The predictive values of preoperative nutritional status for postoperative outcome (morbidity and prognosis) were evaluated. Onodera's PNI was calculated as follows: 10 × serum albumin (g/dL) + 0.005 × lymphocyte count (per mm).The mean preoperative PNI was 47.8. The area under the curve for predicting complications was greater for PNI compared with the serum albumin concentration or lymphocyte count. Multivariate analysis identified preoperative PNI < 47 as an independent predictor of postoperative morbidity. Moreover, patients in the PNI < 47 group experienced significantly shorter overall and disease-free survival compared with those in the PNI ≥ 47 group, notably because of a higher prevalence of hematogenous metastasis as the initial recurrence. Subgroup analysis according to disease stage and postoperative adjuvant treatment revealed that the prognostic significance of PNI was more apparent in patients with stage II GC and in those who received adjuvant chemotherapy.Preoperative PNI is easy and inexpensive to determine, and our findings indicate that PNI served as a significant predictor of postoperative morbidity, prognosis, and recurrence patterns of patients with stage II/III GC.