MiR-5683 suppresses glycolysis and proliferation through targeting pyruvate dehydrogenase kinase 4 in gastric cancer

Gastric cancer (GC) is one of the most deadly malignancies at global scale, and is particularly common in eastern Asia. MicroRNA‐5683 (miR‐5683) was confirmed to be downregulated in GC by analyzing data from the Cancer Genome Atlas. We packaged miR‐5683‐mimics and miR‐5683‐inhibitors into lentivirus vectors and transfected them into GC cells. MiR‐5683 expression and possible target genes were detected by employing quantitative real‐time polymerase chain reaction. In vitro, cell proliferation and apoptosis were analyzed using CCK‐8, colony formation assay, and flow cytometric assay. We verified the direct interaction between miR‐5683 and the possible downstream target gene pyruvate dehydrogenase kinase 4 (PDK4) through luciferase reporter assay. The role of miR‐5683 in vivo was explored by injecting stably transfected GC cells subcutaneously into nude mice. Here we show that miR‐5683 was downregulated in GC and the decreased level of miR‐5683 enhances GC cell proliferation and impairs apoptosis. Tumor oncogene PDK4, which is associated with GC overall survival and disease‐free survival, has been identified as the target gene of miR‐5683. Besides, we demonstrate that the inhibition of miR‐5683 promotes glycolysis by upregulating the PDK4 expression, thus leading to GC progression. Our study determines that miR‐5683 represses GC glycolysis and progression through targeting PDK4. MiR‐5683 overexpression may thus become a new treatment strategy for GC.

HIF-1α regulates cellular metabolism, and Imatinib resistance by targeting phosphogluconate dehydrogenase in gastrointestinal stromal tumors

The pentose phosphate pathway (PPP) plays a critical role in maintaining cellular redox homeostasis in tumor cells and macromolecule biosynthesis. Upregulation of the PPP has been shown in several types of tumor. However, how the PPP is regulated to confer selective growth advantages on drug resistant tumor cells is not well understood. Here we show a metabolic shift from tricarboxylic acid cycle (TCA) to PPP after a long period induction of Imatinib (IM). One of the rate-limiting enzymes of the PPP-phosphogluconate dehydrogenase (PGD), is dramatically upregulated in gastrointestinal stromal tumors (GISTs) and GIST cell lines resistant to Imatinib (IM) compared with sensitive controls. Functional studies revealed that the overexpression of PGD in resistant GIST cell lines promoted cell proliferation and suppressed cell apoptosis. Mechanistic analyses suggested that the protein level of hypoxia inducible factor-1α (HIF-1α) increased during long time stimulation of reactive oxygen species (ROS) produced by IM. Importantly, we further demonstrated that HIF-1α also had positive correlation with PGD, resulting in the change of metabolic pathway, and ultimately causing drug resistance in GIST. Our findings show that long term use of IM alters the metabolic phenotype of GIST through ROS and HIF-1α, and this may contribute to IM resistance. Our work offers preclinical proof of metabolic target as an effective strategy for the treatment of drug resistance in GIST.

Usefulness of three-dimensional printing of superior mesenteric vessels in right hemicolon cancer surgery

The anatomy of the superior mesenteric vessels is complex, yet important, for right-sided colorectal surgery. The usefulness of three-dimensional (3D) printing of these vessels in right hemicolon cancer surgery has rarely been reported. In this prospective clinical study, 61 patients who received laparoscopic surgery for right hemicolon cancer were preoperatively randomized into 3 groups: 3D-printing (20 patients), 3D-image (19 patients), and control (22 patients) groups. Surgery duration, bleeding volume, and number of lymph node dissections were designed to be the primary end points, whereas postoperative complications, post-operative flatus recovery time, duration of hospitalization, patient satisfaction, and medical expenses were designed to be secondary end points. To reduce the influence of including different surgeons in the study, the surgical team was divided into 2 groups based on surgical experience. The duration of surgery for the 3D-printing and 3D-image groups was significantly reduced (138.4 ± 19.5 and 154.7 ± 25.9 min vs. 177.6 ± 24.4 min, P = 0.000 and P = 0.006), while the number of lymph node dissections for the these 2 groups was significantly increased (19.1 ± 3.8 and 17.6 ± 3.9 vs. 15.8 ± 3.0, P = 0.001 and P = 0.024) compared to the control group. Meanwhile, the bleeding volume for the 3D-printing group was significantly reduced compared to the control group (75.8 ± 30.4 mL vs. 120.9 ± 39.1 mL, P = 0.000). Moreover, patients in the 3D-printing group reported increased satisfaction in terms of effective communication compared to those in the 3D-image and control groups. Medical expenses decreased by 6.74% after the use of 3D-printing technology. Our results show that 3D-printing technology could reduce the duration of surgery and total bleeding volume and increase the number of lymph node dissections. 3D-printing technology may be more helpful for novice surgeons.

Trial registration: Chinese Clinical Trial Registry, ChiCTR1800017161. Registered on 15 July 2018.

HMGA1 Regulates the Stem Cell-Like Properties of Circulating Tumor Cells from GIST Patients via Wnt/β-Catenin Pathway

Background

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the digestive system. Circulating tumor cells (CTCs) have been proven to be critical in the recurrence and metastasis of diseases; however, the characteristics of CTCs of GIST are still unclear.

Methods

We sorted out and verified the validity of CTCs from peripheral blood of gastrointestinal stromal tumor (GIST) patients with or without heterochronous liver metastasis using flow cytometry (FCM). Differential genes were analyzed between the GIST patients with and without liver metastasis using next-generation sequencing (NGS).

Results

The preliminary study on the characteristics of CTCs revealed that CTCs of GIST patients with heterochronous liver metastasis had stronger stem cell-like properties (SC-like properties) than CTCs of those without liver metastasis. Furthermore, NGS followed with a series of assays revealed that HMGA1 played a critical role in regulating the SC-like properties of CTCs. Mechanistically, HMGA1 could activate Wnt/β-catenin pathway in vitro and vivo. Moreover, we found that the expression level of HMGA1 in CTCs was an independent risk factor probably influencing the prognosis of GIST patients.

Conclusion

Our findings indicate the significant role of HMGA1 in SC-like properties, IM resistance and eventually hepatic metastasis formation of CTCs. Targeting HMGA1 in CTCs may be a therapeutic strategy for GIST patients with hepatic metastasis.

Downregulation of PHF19 inhibits cell growth and migration in gastric cancer

Objectives: The PHD Finger Protein 19 (PHF19), as a sub-component of polycomb repressive complex 2 (PRC2), has been identified to be associated with various biological processes. Aberrant expression of PHF19 has implicated in several cancer types. This study aims to investigate its function and clinical significance in gastric cancer for the first time.Methods: The expression of PHF19 was evaluated by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. PHF19 was silenced by small interference RNAs and lentiviral particles in gastric cancer cells. Then cell growth was measured by CCK-8 assays, colony formation and in a mouse model. Transwell and wound healing assays were performed to detect cell migration. Western blot analysis was used to explore the downstream signaling factors in PHF19-silenced cells, xenograft tumors and gastric cancer samples.Results: PHF19 was frequently upregulated in gastric cancer tissues compared with adjacent normal stomach tissues and this upregulation was correlated with tumor cell differentiation and poor outcome of gastric cancer patients. Functionally, the silencing of PHF19 in gastric cancer cells led to decreased cell growth and migration. Stable knockdown of PHF19 inhibited the tumorigenicity of gastric cancer cells in nude mice model. Western blot results demonstrated that phosphorylated AKT and ERK were reduced upon PHF19 downregulation, implying the two signaling pathways possibly mediate the oncogenic roles of PHF19.Conclusions: We identified PHF19 as an oncogene candidate and provided a new potential drug target for gastric cancer.

Circulating tumor cells in whole process management of gastrointestinal stromal tumor in a real-life setting

BACKGROUND/AIM

Liquid biopsy is changing the diagnosis and treatment strategies of various neoplasms. However, the circulating tumor cells (CTCs) of gastrointestinal stromal tumor (GIST) patients with different disease process are not clear. To better understand the dynamic change of CTCs in GIST patients, we conducted a real-life setting study.

PATIENTS AND METHODS

One-hundred fifty GIST patients were included. The isolation by size of tumor cell (ISET) method was employed to detect the CTCs/circulating tumor microemboli (CTM). Imatinib (IM) plasma concentration was detected by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Multivariate and univariate analysis were used to analyze the effects of clinical characteristics on the positive rate of CTC and the number of CTCs/CTM.

RESULTS

The positive rate of CTCs was 72%. The median number of CTCs and CTM was 4 and 0. Logistic multivariate regression analysis showed that tumor diameter was the only independent factor of the positive rate of CTCs (P < 0.05). The numbers of CTCs and CTM had intensive linear correlation (P < 0.001). Tumor diameter, Ki 67 expression and mitotic were related to the number of CTCs (P < 0.05). Patients with higher Ki 67 expression tend to have more CTM (P < 0.05). IM plasma concentration showed no influence to the CTCs/CTM (P > 0.05).

CONCLUSIONS

: In the current study, we assessed the CTCs and CTM of GIST patients in various disease progressions and identified clinicopathological factors influencing the detection of CTCs and CTM. These results are instructive for clinicians to understand CTCs/CTM in GIST patients.

Meta-analysis of genome-wide association studies and functional assays decipher susceptibility genes for gastric cancer in Chinese populations

OBJECTIVE

Although a subset of genetic loci have been associated with gastric cancer (GC) risk, the underlying mechanisms are largely unknown. We aimed to identify new susceptibility genes and elucidate their mechanisms in GC development.

DESIGN

We conducted a meta-analysis of four genome-wide association studies (GWASs) encompassing 3771 cases and 5426 controls. After targeted sequencing and functional annotation, we performed in vitro and in vivo experiments to confirm the functions of genetic variants and candidate genes. Moreover, we selected 33 promising variants for two-stage replication in 7035 cases and 8323 controls from other five studies.

RESULTS

The meta-analysis of GWASs identified three loci at 1q22, 5p13.1 and 10q23.33 associated with GC risk at p<5×10^-8 and replicated seven known loci at p<0.05. At 5p13.1, the risk rs59133000[C] allele enhanced the binding affinity of NF-κB1 (nuclear factor kappa B subunit 1) to the promoter of PRKAA1, resulting in a reduced promoter activity and lower expression. The knockout of PRKAA1 promoted both GC cell proliferation and xenograft tumour growth in nude mice. At 10q23.33, the rs3781266[C] and rs3740365[T] risk alleles in complete linkage disequilibrium disrupted and created, respectively, the binding motifs of POU2F1 and PAX3, resulting in an increased enhancer activity and expression of NOC3L, while the NOC3L knockdown suppressed GC cell growth. Moreover, two new loci at 3q11.2 (OR=1.21, p=4.56×10^-9) and 4q28.1 (OR=1.14, p=3.33×10^-11) were associated with GC risk.

CONCLUSION

We identified 12 loci to be associated with GC risk in Chinese populations and deciphered the mechanisms of PRKAA1 at 5p13.1 and NOC3L at 10q23.33 in gastric tumourigenesis.

Therapeutic efficacy of two surgical methods on the secondary hyperparathyroidism

Background

This study aimed to investigate the clinical efficacy of two surgical methods on hyperparathyroidism secondary to uremia and summarize the advantages and disadvantages of both methods.

Methods

Uremic patients who received parathyroidectomy (PTX) in the last 3 years were divided into two groups according to the surgical methods used [subtotal parathyroidectomy (SPTX) group and total parathyroidectomy + autologous implantation (TPTX + AT) group]. TPTX was performed if less than 4 glands were found during surgery. The changes of various indexes after operation, and calculate the success rate and recurrence rate of patients were observed. The serum biochemical parameters were routinely monitored, the success rate, postoperative complications and recurrence were recorded. The patients were followed up.

Results

There were 20 patients in the SPTX group and 12 in the TPTX + AT group. The success rate of surgery was 85% and 91.7% in the SPTX group and TPTX + AT group, respectively, among 32 patients included for final analysis. The mean PTH and postoperative ALP in the TPTX + AT group were slightly lower than in the SPTX group, except for the PTH levels at 6 months after surgery (P<0.05). The incidence of postoperative hypocalcemia was 100% in both groups. The incidence of wound infection in the two groups was 0% and 16.7% in the SPTX group and TPTX + AT group, respectively. The mean calcium supplementation in the TPTX + AT group was significantly more than in the SPTX group within 1 year after surgery. The mean postoperative bone mineral density in the SPTX group was significantly higher than in the TPTX + AT group. The time to postoperative remission of bone pain and muscle weakness was markedly shorter in the SPTX group than in the TPTX + AT group. The post-operative quality of life (QOL) in the SPTX group was significantly better than in the TPTX + AT group.

Conclusions

These findings suggest that SPTX achieves a better short-term efficacy, but TPTX + AT has a better long-term efficacy. Therefore, the selection of surgical method for PTX may be based on the age, estimated survival time and possibility of kidney transplantation.

Association of TP73-AS1 gene polymorphisms with the risk and survival of gastric cancer in a Chinese Han Population

It was investigated that TP73-AS1(TP73 antisense RNA 1) could function as an oncogene in gastric cancer (GC). The expression and function of long noncoding RNAs (lncRNAs) could be impacted by single nucleotide polymorphisms (SNPs), which are related to cancer susceptibility and prognosis. This study was to reveal the association between lncRNAs TP73-AS1 polymorphisms (rs1181865 A > G, rs9800 G > C, rs3737589 A > G, rs2298222 G > A, rs7515164 C > A) and GC in 1000 GC cases and 1000 controls in a Chinese Han population. Rs3737589 G allele had significant associations with the increasing risk of GC (G vs. A: p = .005). Rs3737589 variant genotypes (AG + GG) were related to an increased risk of GC in the elder population (age ≥60), females, nonsmokers, nondrinkers, individuals living in urban, and individuals without family history of GC in stratified analyses. Rs3737589 variant genotypes (AG + GG) were related to the advanced depth of tumor invasion (T3 + T4). Besides, we found that GC patients with AG or GG genotype of rs3737589 had poorer overall survival (OS) than those with AA genotype (p < .05). Our findings showed that the lncRNA TP73-AS1 rs3737589 polymorphism might increase the risk of GC, and rs3737589 polymorphism could be a potential biomarker to predict the prognosis of GC patients.

Laparoscopic versus open total gastrectomy for clinical stage I gastric cancer: Morbidity and mortality results from a prospective randomized multicenter controlled trial (CLASS02)

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Background: The safety of laparoscopic total gastrectomy (LTG) for the treatment of gastric cancer remains lack of clinical evidence. The aim of this study was to compare the safety of LTG for clinical stage I gastric cancer with the conventional open total gastrectomy (OTG). Methods: From January 2017 to September 2018, a total of 227 patients with clinical stage T1N0-1M0/T2N0M0 gastric cancer were enrolled in this clinical trial and randomly assigned to Laparoscopic Gastrectomy group (LG, n=113) or Open Gastrectomy group (OG, n=114). The morbidity and mortality within 30 days following surgery, the recovery course, and the postoperative hospital stay between LG group (n=105) and OG group (n=109) were compared. Clavien-Dindo classification system was used to stratify surgical complications. Results: The overall morbidity rate was not significantly different in each group (LG group: 19.05%; OG group: 20.18%; Rate difference [RD]: -1.14%, 95%CI, -11.75%-9.58%). Intraoperative complications occurred in 3 (2.86%) patients in LG group and 4 (3.67%) patients in OG group (RD: -0.81%, 95%CI, -6.52%-4.85%). In addition, there was no significant difference in the overall postoperative complication rate of 18.10% in LG group and 17.43% in OG group (RD: 0.66%, 95%CI, -9.61%-11.01%). Each subtypes of postoperative complication were not significantly different between groups. One patient in LG group died of intra-abdominal bleeding from splenic artery, and there was no significant difference in mortality between LG group and OG group (RD: 0.95%, 95%CI, -2.54%-5.20%). The distribution of severity was similar between the two groups. Conclusions: Experienced surgeons can safely perform LTG with lymphadenectomy for clinical stage I gastric cancer. Clinical trial information: NCT03007550.

Gastric cancer: Epidemiology, risk factors and prevention strategies

Gastric cancer (GC) is a global health problem, with more than 1 million people newly diagnosed with GC worldwide each year. GC is more prevalent in less developed countries than in more developed countries. About half of all GC cases worldwide occur in East Asia, notably China. Globally, overall incidence rates of GC are declining, which is potentially attributed to a decrease in Helicobacter pylori (H. pylori) infection and the use of refrigeration to preserve foods rather than salt. GC is a multifactorial disease, and its occurrence and development were impacted by environmental and genetic factors. H. pylori infection is the primary risk factor for GC, especially for non-cardia. The prognosis of GC is poor due to stages at the first diagnosis. The 5-year survival rate is less than 10% when patients are diagnosed at an advanced stage, but the rate is as high as 85% if patients are detected at an earlier stage. Endoscopic screening can potentially prevent GC by early diagnosis and early treatment and has been widely adopted in screening programs in East Asian countries, such as Japan and Korea. This review summarizes updated epidemiological aspects, risk factors, and prevention strategies of GC in recent years to help researchers determine the most effective intervention strategies for reducing risk of GC.

Downregulation of NUSAP1 suppresses cell proliferation, migration, and invasion via inhibiting mTORC1 signalling pathway in gastric cancer

Gastric cancer (GC) is one of the most common causes of cancer-related death worldwide, and outstanding biomarkers for therapeutic targets or predicting GC survival are still lacking. Increasing evidence indicated that nucleolar and spindle associated protein 1 (NUSAP1) involved in regulating the progression of various cancers; however, its specific role in GC remained unclear. In this study, we found that NUSAP1 was upregulated in the GC tissues and cell lines via analysing data from The Cancer Genome Atlas (TCGA), gene expression omnibus (GEO), qRT-PCR, and western blot assays. Patients with high NUSAP1 expression levels showed shorter free-progression survival (FPS), larger tumour size, and higher lymphatic metastasis rate compared with those with low NUSAP1 expression. Further functional experiments revealed knockdown of NUSAP1 could inhibit the growth, migration, and invasion of GC cells in vitro and vivo. Additionally, silencing NUSAP1 induced G0/G1 phase arrest, apoptosis, and suppressed the epithelial-mesenchymal transition (EMT) process. Finally, we performed gene set enrichment analysis (GSEA) and observed NUSAP1 was positive with mTORC1 signalling pathway, which was verified by the subsequent immunoblotting. In conclusion, our findings suggested that NUSAP1 contributed to GC progression and may act as a potential therapeutic target for GC. SIGNIFICANCE OF THE STUDY: Our results firstly illuminated that NUSAP1 expression was significantly upregulated in GC tissues and predicted poor FPS. Silencing it could attenuate GC progression via inhibiting mTORC1 signalling pathway. Hence, NUSAP1 may act as a promising therapy target for GC.

STRA6 exerts oncogenic role in gastric tumorigenesis by acting as a crucial target of miR-873

Background

Increasing evidence shows that stimulated by retinoic acid 6 (STRA6) participates in regulating multiple cancers. However, the biological roles of STRA6 in gastric cancer (GC) remain unknown. This study aimed to investigate the biological function of STRA6 and reveal the underlying mechanism of its dysregulation in GC.

Methods

The expression level of STRA6 was detected through quantitative real-time PCR and Western blot analysis. The effects of STRA6 on the proliferation of GC cells were studied through CCK-8 proliferation, colony formation and 5-ethynyl-2′-deoxyuridine (EdU) assays. The effects of STRA6 on migration and invasion were detected via wound healing and Transwell assays. Upstream miRNAs, which might regulate STRA6 expression, was predicted through bioinformatics analysis. Their interaction was further confirmed through dual-luciferase reporter assays and rescue experiments.

Results

STRA6 was up-regulated in GC and enhanced the proliferation and metastasis of GC cells in vitro and in vivo. STRA6 knockdown could inhibit the Wnt/β-catenin signalling pathway. STRA6 was confirmed as an miR-873 target, which acted as a tumour suppressor in GC. Rescue assays showed that the repressing effect of miR-873 could be partially reversed by overexpressing STRA6.

Conclusions

STRA6 is down-regulated by miR-873 and plays an oncogenic role by activating Wnt/β-catenin signalling in GC.

In-Hospital Mortality Risk Model of Gastric Cancer Surgery: Analysis of a Nationwide Institutional-Level Database With 94,277 Chinese Patients

Background: The objective of this study is to identify independent risks and protective factors and to construct a mortality prediction model for gastrectomy in the Chinese population.

Study design: This is a population-based prospective cohort at an institutional level. Seventy-two participating hospitals reported their annual gastrectomy data between 2014 and 2016, while 44 variables covering the institution and surgical information were included in the analysis. We used R software to encode and complete data pre-processing. The first difference model was applied to build the risk model. Data from 2014 and 2015 were assigned to risk model development, while data from 2016 was used for validation.

Results: In the included centers with 94,277 gastric cancer cases, the in-hospital mortality rate was 0.32%. The regression model revealed that provinces with low-middle GDP, hospitals with annual gastrectomy volume between 100 and 500, greater volume of urgent surgeries performed, larger proportion of males, and a higher proportion of liver metastasis were independent risk factors for mortality following gastric surgeries, while higher laparoscopic resection volume, greater volume of distal gastrectomy with B2 reconstruction, and larger proportion of palliative surgery were independent protective factors (p < 0.05, respectively). In the prediction test, the mean square error of the training set was 0.948, while that of the test set was 0.728, demonstrating the effectiveness of this model.

Conclusions: We constructed the first mortality risk prediction model for gastric cancer surgery in the Chinese population. The identified risk factors will help with the therapy selection, while further informing Chinese medical policy decision-makers.

Chronic stress promotes gastric cancer progression and metastasis: an essential role for ADRB2

An increasing number of studies indicate that adrenergic signalling plays a fundamental role in chronic stress-induced tumour progression and metastasis. However, its function in gastric cancer (GC) and its potential mechanisms remain unknown. The expression levels of β-adrenergic receptor (ADRB) in GC cell lines were examined by using real-time polymerase chain reaction (RT-PCR) and western blotting. The effects of β2 adrenergic receptor (ADRB2) activation and blockade were investigated in vitro in GC cells by using proliferation, migration, invasion, cell cycle and apoptosis assays. Chronic restraint stress (CRS) increased the plasma levels of catecholamines and cortisol and also induced progression and metastasis of GC in vivo. Furthermore, immunohistochemical staining and a TUNEL assay were employed to observe the regulation of cell viability in vivo. The expression levels of ADRB2 in 100 human GC samples were measured by RT-PCR and immunohistochemistry. The stress hormones epinephrine and norepinephrine significantly accelerated GC cell proliferation, invasion and viability in culture, as well as tumour growth in vivo. These effects were reversed by the ADRB antagonists propranolol and ICI118,551 (an ADRB2-specific antagonist). Moreover, the selective ADRB1 antagonist atenolol had almost no effect on tumour cell proliferation and invasion in vitro and in vivo. ADRB2 antagonists suppressed proliferation, invasion and metastasis by inhibiting the ERK1/2-JNK-MAPK pathway and transcription factors, such as NF-κB, AP-1, CREB and STAT3. Analysis of xenograft models using GC cells revealed that ADRB2 antagonists significantly inhibited tumour growth and metastasis, and chronic stress antagonized these inhibitory effects. In addition, chronic stress increased the expression of VEGF, MMP-2, MMP-7 and MMP-9 in transplanted tumour tissue, and catecholamine hormones enhanced the expression of metastasis-related proteins. The expression of ADRB2 was upregulated in tumour tissues and positively correlated with tumour size, histological grade, lymph node metastasis and clinical stage in human GC samples. Stress hormone-induced activation of the ADRB2 signalling pathway plays a crucial role in GC progression and metastasis. These findings indicate that ADRB2 signalling regulates GC progression and suggest β2 blockade as a novel strategy to complement existing therapies for GC.

Adenosquamous Carcinoma of the Stomach: A Population-based Study from the SEER Database

Purpose: Gastric adenosquamous carcinoma (ASC) is a rare pathological type with poorly understood clinicopathological features. The purpose of this study is to identify the characteristics of gastric ASC patients.

Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database (2000 to 2014), patients with ASC (N=93) or adenocarcinoma (AC) (N=41794) of the stomach were included. The epidemiology, tumor features, treatment, and outcomes between these two groups were compared.

Results: The incidences of ASC from 1983 to 2014 [annual percentage change (APC) = -3.5%, 95% confidence interval (CI) -4.9 to -2.1] and AC from 1973-2014 [APC = -1.8%, 95%CI -2.0 to -1.6] decreased over time. Compared to AC cases, patients with ASC were more likely to present poor differentiation (74.2% vs 52.4%) and later summary stage (distant: 46.2% vs 33.6%) or later T stage (T4: 15.1%% vs 9.0%). Besides, the proportion of patients with distant metastasis (33.3% vs 23.9%), and chemotherapy (44.1% vs 34.0%) in ASC group was higher. The Kaplan-Meier analyses showed ASC cases had worse overall survival (OS) (p=0.017) than that of AC after propensity score matching (PSM), but not the cancer-specific survival (CSS) (p=0.849). The further subgroup analyses suggested no statistical significance between gastric ASC patients and AC patients for CSS. The multivariate cox proportional hazard analyses indicated that patients with distant summary stage (HR=2.11, p=0.014), no surgery (HR=2.22, p=0.016), and no/unknown chemotherapy (HR=3.33, p<0.001) were associated with poor OS for ASC population alone. However, for CSS, only ASC cases with no/unknown chemotherapy (HR=2.22, p=0.018) indicated worse outcomes.

Conclusions: Gastric ASC presented more aggressive clinicopathologic characteristics and poorer OS compared with AC. The localized/regional summary stages and undergoing surgery suggested favorable OS for gastric ASC patients. ASC cases receiving chemotherary showed both better OS and CSS.

PRDX2 protects against oxidative stress induced by H. pylori and promotes resistance to cisplatin in gastric cancer

BACKGROUND

Helicobacter pylori (H. pylori) infection is the main risk factor for gastric cancer. The role of antioxidant enzyme peroxiredoxin 2 (PRDX2) in gastric tumorigenesis remains unknown. In vitro (AGS and SNU-1 cell lines) and in vivo mouse models were utilized to investigate the role of PRDX2 in response to H. pylori infection (7.13, J166 or PMSS1 strain). We detected high levels of PRDX2 expression in gastric cancer tissues. Gastric cancer patients with high expression levels of PRDX2 had significantly worse overall and progression-free survival than those with low levels. H. pylori infection induced activation of NF-κB with increased expression of PRDX2, in in vitro and in vivo models. The knockdown of PRDX2 led to an increase in the levels of reactive oxygen species (ROS), oxidative DNA damage, and double-strand DNA breaks, in response to H. pylori infection, as measured by H₂DCFDA, 8-oxoguanine, and p-H2AXγ assays. Luciferase reporter and ChIP assays confirmed the presence of a putative binding site of NF-κB-p65 on PRDX2 promoter region. The inhibition of PRDX2 significantly sensitized AGS and SNU-1 cells to cisplatin treatment. Our data suggest that the future development of therapeutic approaches targeting PRDX2 may be useful in the treatment of gastric cancer.

Circular RNA profile identifies circOSBPL10 as an oncogenic factor and prognostic marker in gastric cancer

The prognosis after curative resection of gastric cancer (GC) remains unsatisfactory, and thus, the development of treatments involving alternative molecular and genetic targets is critical. Circular RNAs (circRNAs), which are newly discovered molecules with key roles in the non-coding RNA network, have been identified as critical regulators in various cancers. Here, we aimed to determine the circRNA expression profile and to investigate the functional and prognostic significance of circRNA in GC. Using next-generation sequencing profiling, we first characterized an abundant circRNA in GC, hsa_circ_0008549, derived from the OSBPL10 gene and named it circOSBPL10. The expression of circOSBPL10 was found to be upregulated in GC tissues by quantitative RT-PCR, and silencing of circOSBPL10 significantly inhibited GC cell growth, migration, and invasion in multiple experiments. We further confirmed that miR-136-5p is a downstream target of circOSBPL10 using RNA pull-down and luciferase reporter assays. Rescue experiments confirmed that circOSBPL10 regulates biological functions in GC cells via a circOSBPL10-miR-136-5p-WNT2 axis. In vivo experiments showed that circOSBPL10 promotes tumor growth and metastasis in mice. Furthermore, the level of circOSBPL10 was observed to be a prognostic marker of the overall survival and disease-free survival of patients with GC. Taken together, our findings reveal that circOSBPL10 may serve as a new proliferation factor and prognostic marker in GC.

Abstract 885: Induction of PRDX2 by H. pylori reduces ROS and promotes cancer cell survival and resistance to cisplatin

Background & Aims: The antioxidant enzyme peroxiredoxin 2 (PRDX2) plays a critical role in regulating reactive oxygen species (ROS) levels in several diseases. Helicobacter pylori (H. pylori) infection is a well-known risk factor of gastric cancer. The role of PRDX2 in gastric tumorigenesis remains largely unknown. We investigated the molecular function and regulation of PRDX2 in response to infection with H. pylori and cisplatin treatment in gastric cancer cells.

Methods:Western blots (WB) and quantitative real-time PCR (qPCR) analysis were performed on AGS, SNU-1 and MKN28 gastric cancer cell lines to detect PRDX2 expression levels with or without H. pyloriinfection (7.13 or J166 strain). We evaluated the levels of ROS by H2DCFDA staining. WB analysis was used to determine oxidative DNA damage and double stranded DNA breaks by using antibodies against 8-Oxo-guanine and p-H2AX. WB and NF-κb luciferase reporter assay were performed to investigate the link between PRDX2 and NF-κb signaling. ATP-GLO cell titer analysis was utilized to determine cell viability.

Results:Our data indicated that PRDX2 mRNA and protein expression levels were induced byH. pyloriin AGS and SNU-1 cells. PRDX2 knockdown significantly increased ROS levels and 8-Oxoguanine staining followingH. pyloriinfection in both cells. These results were further confirmed by Western blot data showing that p-H2AX protein level was strongly induced in PRDX2 knockdown and H. pyloriinfected cells. Interestingly, Western blot data showed that TNF-αtreatment induced PRDX2 protein levels while Bay 11-7082 treatment decreased PRDX2 protein level in AGS and SNU-1 cells. At the same time, PRDX2 transient knockdown in both AGS and SNU-1 cells decreased p-P65 (S536) protein expression levels, nuclear localization of NF-κB-p65, and luciferase reporter activity (P&lt;0.05). We also found that inhibition of PRDX2 significantly sensitized AGS and SNU-1 cells to cisplatin treatment.

Conclusion:Our data indicates that knockdown of PRDX2 enhances ROS and DNA damage with H. pylori infection on gastric cancer cells after H. pylori infection and sensitizes gastric cancer cells to cisplatin treatment. Our results suggest a positive feedforward loop between PRDX2 and NF-kB to reduce ROS levels.

KEY WORDS: PRDX2,H. pylori, gastric cancer, reactive oxygen species, DNA damage, NF-κb

Citation Format: Sen Wang, Zheng Chen, Heng Lu, Shoumin Zhu, Dunfa Peng, Mohammed Soutto, Ahmed Gomma, Nadeem Bhat, Huma Naz, Zekuan Xu, Wael El-Rifai. Induction of PRDX2 by H. pylori reduces ROS and promotes cancer cell survival and resistance to cisplatin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 885.

Netrin-1 promotes cell neural invasion in gastric cancer via its receptor neogenin

Neural invasion (NI) is one of the important routes for local spread of gastric cancer (GC) correlated with poor prognosis. However, the exact cellular characteristics and molecular mechanisms of NI in GC are still unclear. Netrin-1(NTN1) as an axon guidance molecule was firstly found during neural system development. Importantly, NTN1 has an essential role in the progression of malignant tumor and specifically mediates the induction of invasion. In this study, we found NTN1 expression was significantly increased in 97 tumor tissues from GC patients and positively correlated with NI (p<0.05). In addition, we detected NTN1 knockdown significantly suppressed GC cells migration and invasion. Moreover, our results showed that reciprocity was observed between GC cells and neurites colonies in dorsal root ganglia (DRG)-GC cells co-culture vitro model. GC cells with NTN1 silencing could suppress their abilities to navigate along surrounding neuritis and this effect was depended on its receptor neogenin. In vivo, NTN1 inhibition also decreased GC cells sciatic nerve invasion. Taken together, our findings argue that NTN1 and its receptor neogenin might act synergistically in promoting GC cells neural invasion. Inhibiting the activity of NTN1 could be a potential strategy targeting NI in GC therapy.

Reduced USP33 expression in gastric cancer decreases inhibitory effects of Slit2-Robo1 signalling on cell migration and EMT

OBJECTIVES

Gastric cancer (GC) is one of the most common cancers in the world, causing a large number of deaths every year. The Slit-Robo signalling pathway, initially discovered for its critical role in neuronal guidance, has recently been shown to modulate tumour invasion and metastasis in several human cancers. However, the role of Slit-Robo signalling and the molecular mechanisms underlying its role in the pathogenesis of gastric cancer remains to be elucidated.

MATERIALS AND METHODS

Slit2, Robo1 and USP33 expressions were analysed in datasets obtained from the Oncomine database and measured in human gastric cancer specimens. The function of Slit2-Robo1-USP33 signalling on gastric cancer cells migration and epithelial-mesenchymal transition (EMT) was studied both in vitro and in vivo. The mechanism of the interaction between Robo1 and USP33 was explored by co-IP and ubiquitination protein analysis.

RESULTS

The mRNA and protein levels of Slit2 and Robo1 are lower in GC tissues relative to those in adjacent healthy tissues. Importantly, Slit2 inhibits GC cell migration and suppresses EMT process in a Robo-dependent manner. The inhibitory function of Slit2-Robo1 is mediated by ubiquitin-specific protease 33 (USP33) via deubiquitinating and stabilizing Robo1. USP33 expression is decreased in GC tissues, and reduced USP33 level is correlated with poor patient survival.

CONCLUSIONS

Our study reveals the inhibitory function of Slit-Robo signalling in GC and uncovers a role of USP33 in suppressing cancer cell migration and EMT by enhancing Slit2-Robo1 signalling. USP33 represents a feasible choice as a prognostic biomarker for GC.

miR-664a-3p functions as an oncogene by targeting Hippo pathway in the development of gastric cancer

OBJECTIVES

It has been accounted that miR-664a-3p has different functions in several malignancies; however, the precise role and underlying mechanism in gastric cancer have not been elucidated. Our study aims to explore the function of miR-664a-3p on the progression of gastric cancer (GC).

METHODS

qRT-PCR was applied to detect the expression of miR-664a-3p in GC tissues and cells. The functions of miR-664a-3p on GC in vitro were examined by cell proliferation assay, and transwell assay. Related proteins of epithelial-mesenchymal transition (EMT) and signal pathway were evaluated by Western blot and immunofluorescence analysis. The bioinformatic, dual-luciferase assay or ChIP assay were employed to identify the interaction between miR-664a-3p and its target gene or Foxp3. The effects in vivo were investigated through a mouse tumorigenicity model.

RESULTS

miR-664a-3p was frequently upregulated in GC tissues and cells. Elevated expression of miR-664a-3p significantly promoted proliferation and invasion in vitro and in vivo. MOB1A was confirmed to be a target of miR-664a-3p and restoration of MOB1A attenuated the effects of miR-664a-3p. A series of investigations indicated that miR-664a-3p contributed to EMT process and inactivated the Hippo pathway by downregulating MOB1A.

CONCLUSION

Taken together, we revealed that miR-664a-3p functions as an oncogene by targeting Hippo pathway in the development of gastric cancer.

Circular RNA AKT3 upregulates PIK3R1 to enhance cisplatin resistance in gastric cancer via miR-198 suppression

BACKGROUND

Cisplatin (CDDP) treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). A better understanding of the mechanisms of CDDP resistance can greatly improve therapeutic efficacy in patients with GC. Circular RNAs (circRNAs) are a class of noncoding RNAs whose functions are related to the pathogenesis of cancer, but, in CDDP resistance of GC remains unknown.

METHODS

circAKT3 (hsa_circ_0000199, a circRNA originating from exons 8, 9, 10, and 11 of the AKT3 gene) was identified by RNA sequencing and verified by quantitative reverse transcription PCR. The role of circAKT3 in CDDP resistance in GC was assessed both in vitro and in vivo. Luciferase reporter assay, biotin-coupled RNA pull-down and fluorescence in situ hybridization (FISH) were conducted to evaluate the interaction between circAKT3 and miR-198. Functional experiments were measured by western blotting, a cytotoxicity assay, clonogenic assay and flow cytometry.

RESULTS

The expression of circAKT3 was higher in CDDP-resistant GC tissues and cells than in CDDP-sensitive samples. The upregulation of circAKT3 in GC patients receiving CDDP therapy was significantly associated with aggressive characteristics and was an independent risk factor for disease-free survival (DFS). Our data indicated that circAKT3 promotes DNA damage repair and inhibits the apoptosis of GC cells in vivo and in vitro. Mechanistically, we verified that circAKT3 could promote PIK3R1 expression by sponging miR-198.

CONCLUSIONS

circAKT3 plays an important role in the resistance of GC to CDDP. Thus, our results highlight the potential of circAKT3 as a therapeutic target for GC patients receiving CDDP therapy.

Adrenergic modulation of AMPK‑dependent autophagy by chronic stress enhances cell proliferation and survival in gastric cancer

Epidemiological data show that chronic stress has adverse effects on the incidence and progression of cancer. As a critical target organ for stress hormones, the stomach is frequently subjected to stress-related injury. However, few reports regarding the association between stress and gastric cancer (GC) have been published. The present study aimed to investigate the effect of chronic stress on the growth and survival of GC, and the role of the autophagy process. A restraint-stress procedure over 21 days was used to establish a chronic stress mouse model. Subcutaneous xenografts and gastric orthotopic xenografts were established in BALB/c nude mice. Alzet osmotic minipumps containing either PBS or propranolol hydrochloride was inserted on the nape of the neck 7 days prior to the initiation of restraint stress. The presence of autophagosomes and autolysosomes were examined by electron microscopy. The stress hormone norepinephrine significantly enhanced the proliferation of GC cells. By inhibiting adrenoreceptor expression, it was demonstrated that β2-adrenergic receptor (ADRB2) was the specific β-adrenergic receptor subtype responsible for catecholamine release. In addition, it was demonstrated that the induction of autophagy was a novel consequence of β2-adrenergic activation in GC cells. This was demonstrated by the appearance of double-membrane vesicles, punctuate GFP-RFP-microtubule-associated protein 1 light chain 3 distribution in the cytoplasm and a corresponding increase in autophagic flux. Notably, norepinephrine-induced autophagy was shown to have a tumor-promoting role under conditions of chronic stress in vitro and in vivo. It was further demonstrated that, upon activation of cAMP-response element binding protein, chronic stress promoted autophagic flux through the adenosine 5′-monophosphate-activated protein kinase-unc-51 like autophagy activating kinase 1 (AMPK-ULK1) pathway. Tissue microarray analysis revealed a negative correlation between the expression of ADRB2 and autophagic marker p62/sequestosome-1 in GC tumor samples. Additionally, high protein levels of ADRB2 correlated positively with tumor, node, metastasis stage and poor prognosis in patients with GC. These results establish a novel pathway that chronic stress activates tumor-promoting autophagy to accelerate the progression of GC. The present study is the first, to the best of our knowledge, providing preclinical evidence that chronic stress serves a role in the progression of GC.

Integrated Analysis of Mouse and Human Gastric Neoplasms Identifies Conserved microRNA Networks in Gastric Carcinogenesis

BACKGROUND & AIMS

microRNAs (miRNAs) are small noncoding RNAs that bind to the 3' untranslated regions of mRNAs to promote their degradation or block their translation. Mice with disruption of the trefoil factor 1 gene (Tff1) develop gastric neoplasms. We studied these mice to identify conserved miRNA networks involved in gastric carcinogenesis.

METHODS

We performed next-generation miRNA sequencing analysis of normal gastric tissues (based on histology) from patients without evidence of gastric neoplasm (n = 64) and from TFF1-knockout mice (n = 22). We validated our findings using 270 normal gastric tissues (including 61 samples from patients without evidence of neoplastic lesions) and 234 gastric tumor tissues from 3 separate cohorts of patients and from mice. We performed molecular and functional assays using cell lines (MKN28, MKN45, STKM2, and AGS cells), gastric organoids, and mice with xenograft tumors.

RESULTS

We identified 117 miRNAs that were significantly deregulated in mouse and human gastric tumor tissues compared with nontumor tissues. We validated changes in levels of 6 miRNAs by quantitative real-time polymerase chain reaction analyses of neoplastic gastric tissues from mice (n = 39) and 3 independent patient cohorts (n = 332 patients total). We found levels of MIR135B-5p, MIR196B-5p, and MIR92A-5p to be increased in tumor tissues, whereas levels of MIR143-3p, MIR204-5p, and MIR133-3p were decreased in tumor tissues. Levels of MIR143-3p were reduced not only in gastric cancer tissues but also in normal tissues adjacent to tumors in humans and low-grade dysplasia in mice. Transgenic expression of MIR143-3p in gastric cancer cell lines reduced their proliferation and restored their sensitivity to cisplatin. AGS cells with stable transgenic expression of MIR143-3p grew more slowly as xenograft tumors in mice than control AGS cells; tumor growth from AGS cells that expressed MIR143-3p, but not control cells, was sensitive to cisplatin. We identified and validated bromodomain containing 2 (BRD2) as a direct target of MIR143-3p; increased levels of BRD2 in gastric tumors was associated with shorter survival times for patients.

CONCLUSIONS

In an analysis of miRNA profiles of gastric tumors from mice and human patients, we identified a conserved signature associated with the early stages of gastric tumorigenesis. Strategies to restore MIR143-3p or inhibit BRD2 might be developed for treatment of gastric cancer.

MIR-1265 regulates cellular proliferation and apoptosis by targeting calcium binding protein 39 in gastric cancer and, thereby, impairing oncogenic autophagy

Increasing evidence indicates that microRNAs (miRNAs) play an important role in various tumors by regulating downstream target genes and diverse signaling pathways. Herein, we confirmed miR-1265 expression in gastric cancer (GC) using the Cancer Genome Atlas (TCGA) database and assessed the level of miR-1265 expression in clinical specimens and cell lines. We found that miR-1265 expression was negatively correlated with tumor size. Further functional analysis revealed that miR-1265 suppresses cellular proliferation and autophagy while inducing apoptosis in GC cells. A luciferase reporter assay was used to identify an miR-1265 targeted gene, calcium binding protein 39 (CAB39), which is an essential upstream regulator in the AMPK-mTOR signaling pathway. Upregulation or downregulation of CAB39 expression reversed the effects of miR-1265 overexpression or inhibition, respectively. Notably, the knockdown of autophagy-related gene 12 (ATG12) impaired the effects of miR-1265 inhibition or CAB39 overexpression in GC. MiR-1265 also suppressed the growth of GC cells in vivo and that of human gastric organoids. Altogether, our results show that miR-1265 suppresses GC progression and oncogenic autophagy by reducing CAB39 expression and regulating the AMPK-mTOR signaling pathway. Therefore, miR-1265 may represent a potential therapeutic target for GC.

Circular RNA circNRIP1 acts as a microRNA-149-5p sponge to promote gastric cancer progression via the AKT1/mTOR pathway

Background

CircRNA has emerged as a new non-coding RNA that plays crucial roles in tumour initiation and development. ‘MiRNA sponge’ is the most reported role played by circRNAs in many tumours. The AKT/mTOR axis is a classic signalling pathway in cancers that sustains energy homeostasis through energy production activities, such as the Warburg effect, and blocks catabolic activities, such as autophagy. Additionally, the AKT/mTOR axis exerts a positive effect on EMT, which promotes tumour metastasis.

Methods

We detected higher circNRIP1 expression in gastric cancer by performing RNA-seq analysis. We verified the tumour promotor role of circNRIP1 in gastric cancer cells through a series of biological function assays. We then used a pull-down assay and dual-luciferase reporter assay to identify the downstream miR-149-5p of circNRIP1. Western blot analysis and immunofluorescence assays were performed to demonstrate that the circNRIP1-miR-149-5p-AKT1/mTOR axis is responsible for the altered metabolism in GC cells and promotes GC development. We then adopted a co-culture system to trace circNRIP1 transmission via exosomal communication and RIP experiments to determine that quaking regulates circNRIP1 expression. Finally, we confirmed the tumour suppressor role of microRNA-133a-3p in vivo in PDX mouse models.

Results

We discovered that knockdown of circNRIP1 successfully blocked proliferation, migration, invasion and the expression level of AKT1 in GC cells. MiR-149-5p inhibition phenocopied the overexpression of circNRIP1 in GC cells, and overexpression of miR-149-5p blocked the malignant behaviours of circNRIP1. Moreover, it was proven that circNRIP1 can be transmitted by exosomal communication between GC cells, and exosomal circNRIP1 promoted tumour metastasis in vivo. We also demonstrated that quaking can promote circNRIP1 transcription. In the final step, the tumour promotor role of circNRIP1 was verified in PDX models.

Conclusions

We proved that circNRIP1 sponges miR-149-5p to affect the expression level of AKT1 and eventually acts as a tumour promotor in GC.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0935-5) contains supplementary material, which is available to authorized users.

Intracellular concentration and transporters in imatinib resistance of gastrointestinal stromal tumor

BACKGROUND

We aimed to investigate the role of intracellular imatinib concentration in drug resistance and the expression of candidate drug transporters in gastrointestinal stromal tumor (GIST) cell lines.

METHOD

The imatinib concentrations were measured by the liquid chromatography-tandem mass spectrometry (LC-MS/MS). The expression of candida te drug transporters was detected by qRT-PCR.

RESULTS

The tissue imatinib concentrations in imatinib resistant patients were significantly lower than that of sensitive patients (p < .05). Compared with parental cell lines, the intracellular imatinib concentration was notably lower in imatinib resistant GIST cell lines. For candidate transporters, MRP1 and BCRP were overexpressed in resistant GIST cell lines.

CONCLUSION

The intracellular imatinib concentration may play a crucial role in imatinib resistance and the intracellular differences of imatinib concentration may be induced by the upregulation of efflux transporters. Our study highlights the importance of intracellular imatinib concentration and the potential of using imatinib transporters as therapeutic targets for patients with GIST.

Novel role of miR-133a-3p in repressing gastric cancer growth and metastasis via blocking autophagy-mediated glutaminolysis

Background

Autophagy plays a crucial role in sustaining the homeostasis in various malignant diseases. It has also been reported to promote tumor development in multiple cancers. Glutaminolysis instead of Warburg Effect produce adequate ATP and provide nitrogen and carbon to replenish the TCA cycle which has been discovered to be a new energy source for tumor cells recently. By means of degrading intracellular particles including amino acids, nucleotides, fatty acids, sugars and aged organisms, autophagy can recycle the aforementioned particles into bioenergetics and biosynthesis pathways, finally favoring tumor cells. MicroRNA is a kind of noncoding RNA that regulates the targeting gene expression mostly at post-transcription level. Among these miRNAs, microRNA-133a-3p is reported to be a tumor suppressor in numerous cancers.

Methods

We characterized the down-regulated expression level of microRNA-133a-3p in gastric cancer via TCGA database. Subsequently, we verified the tumor suppressor role of microRNA-133a-3p in gastric cancer cells through a series biological function assay. We used immunofluorescence and transmission electron microscope to observe the negative effect of microRNA-133a-3p on autophagy and used dual-luciferase report assay to identify the candidate gene GABARAPL1 of microRNA-133A-3p.Then we used high performance liquid phase mass spectrometry and seahorse analysis to detect whether miR-133a-3p could block the glutaminolysis metabolism through autophagy. At last, we confirmed the tumor suppressor role of microRNA-133a-3p in vivo on PDX mice model.

Results

We demonstrated that microRNA-133a-3p overexpression could block the activation of autophagy to ruin the abnormal glutaminolysis and further inhibit the growth and metastasis of gastric cancer cells. We successfully proved gastric cancer cells can replenish glutaminolysis via autophagy and microRNA-133a-3p could block aforementioned pathway by targeting core autophagy participants GABARAPL1 and ATG13.We then verified the negative function of microRNA-133a-3p on autophagy-mediated glutaminolysis both in PDX model and human gastric cancer organoid model.

Conclusions

MicroRNA-133a-3p targets GABARAPL1 to block autophagy-mediated glutaminolysis, further repressing gastric cancer growth and metastasis.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0993-y) contains supplementary material, which is available to authorized users.

[Feasibility and efficacy of laparoscopic treatment for advanced gastric cancer from LOC-A study]

With the progression of surgical techniques, laparoscopic equipment and treatment concepts, laparoscopic radical gastrectomy has been widely used in clinical practice. However, whether laparoscopic surgery can be used for the treatment of locally advanced gastric cancer is still controversial. Recent results from the Korean KLASS-02 study, the Japanese JCOG-0901 study, and the Chinese CLASS-01 study suggest that there is no significant difference in the short-term efficacy between laparoscopic surgery and open surgery in the treatment of locally advanced gastric cancer. The long-term results have not been published. The LOC-A study was a multicenter, large sample size retrospective analysis that enrolled 1948 laparoscopic and open surgery cases with stage II to III locally advanced gastric cancer in 8 Japanese hospitals between 2008 and 2014. As a result, after removal of confounding factors by propensity score matching (PSM), the analysis showed no significant difference in long-term efficacy between laparoscopic surgery and open surgery for locally advanced gastric cancer. However, some bias still remain after the bias-control. Therefore, due to insufficiency of the high-level evidence-based medical evidence, we believe that the all-round promotion of laparoscopic surgery of locally advanced gastric cancer is too early, nevertheless, we should also recognize that the minimally invasive treatment of gastric cancer is the current development trend, and we should be confident in laparoscopic treatment of locally advanced gastric cancer.

Assessment of the Biocompatibility and Biological Effects of Biodegradable Pure Zinc Material in the Colorectum

Little attention has been paid to the biocompatibility and biological effects of zinc as a material. Here, we therefore investigated the biocompatibility and anti-inflammatory and collagen-promoting effects of pure zinc material in the colorectum. Our in vitro results indicated that zinc toxicity and concentration were closely related. Low concentrations of zinc ions and pure zinc material extract had only minor effects on the viability of primary rectal mucosal epithelial cells; however, cytotoxicity was observed at concentrations greater than 0.017 μg/μL and 60%, respectively. In vivo experiments demonstrated that zinc pins degraded slowly in the colorectum (their volume decreasing by approximately 7.79% over 1 month) and did not cause serious adverse reactions. Pure zinc material was found to inhibit acute inflammation through increased expression of ENA-78 and F4/80. Moreover, zinc material heightened expression of collagen and VEGF, factors conducive to wound healing, in surrounding colorectal tissues. These preliminary results suggest that zinc shows great promise as an implant material for medical applications involving colorectal surgery.

Association of Imatinib Plasma Concentration and Single-nucleotide Polymorphisms with Adverse Drug Reactions in Patients with Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GIST) are the most prevalent mesenchymal tumors of the digestive tract. To investigate the association of imatinib mesylate plasma concentration with adverse drug reactions (ADRs) and influences of genetic polymorphisms on ADRs in GIST patients taking imatinib, a cohort of GIST patients consecutively treated with imatinib were included in the observational study. Clinical, pathologic and genotype information was recorded at enrollment and blood samples were collected at time as design. The plasma concentration of the imatinib was detected by LC-MS/MS. A questionnaire was used to evaluate the ADRs at each visit. SNPs in 13 genes were analyzed for a possible association with ADRs. The mean plasma trough concentration of 129 patients taking imatinib was 1.45 ± 0.79 μg/ml, average peak concentration was 2.63 ± 1.07 μg/ml. The imatinib concentration in patients treated with 600 mg/day was significantly higher than other dosage groups (P < 0.05). The ADRs were mostly mild. Edema, vomiting, and fatigue were significantly correlated with imatinib concentration (P < 0.05). Mutations of IL13 rs1800925 and CXCL14 rs7716492 were related with the incidence of leukopenia and rash in our research, separately (P < 0.05). We confirmed that with the increase of imatinib concentration, the incidence of edema, vomiting, and fatigue rises as well. Mutations of IL13 rs1800925 and CXCL14 rs7716492 may be the promising biomarkers to predict the ADRs of imatinib. The results of the study are of guiding significance for the use of imatinib in patients with GIST.

Study on safety of laparoscopic total gastrectomy for clinical stage I gastric cancer: the protocol of the CLASS02-01 multicenter randomized controlled clinical trial

BACKGROUND

The safety of laparoscopic total gastrectomy (LTG) for the treatment of gastric cancer remains lack of clinical evidence. The Chinese Laparoscopic Gastrointestinal Surgery Study (CLASS) Group recently launched a multicenter randomized clinical trial (CLASS02-01) to compare the safety of LTG for clinical stage I gastric cancer with the conventional open total gastrectomy (OTG).

METHODS

This CLASS02-01 trial is a prospective, multicenter, randomized, controlled, open, and non-inferiority trial. Two hundred patients who met the inclusion criteria and did not accord with the exclusion criteria will be randomly divided into LTG group (n = 100) and OTG group (n = 100). The primary purpose of this study is to evaluate the early operative morbidity and mortality of LTG compared with OTG for clinical stage I gastric adenocarcinoma. The second purpose is to evaluate the recovery course and compare the postoperative hospital stay of the patients enrolled in this study.

DISCUSSION

This CLASS02-01 trial is the first prospective randomized two-arm controlled study to determine the safety of LTG compared with OTG. Through this trial, we hope to show that experienced surgeons can safely perform LTG with lymphadenectomy for gastric cancer.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03007550 . December 30, 2016.

Exosomal miR-21-5p derived from gastric cancer promotes peritoneal metastasis via mesothelial-to-mesenchymal transition

Peritoneal metastasis is a primary metastatic route for gastric cancers, and the mechanisms underlying this process are still unclear. Peritoneal mesothelial cells (PMCs) undergo mesothelial-to-mesenchymal transition (MMT) to provide a favorable environment for metastatic cancer cells. In this study, we investigated how the exosomal miR-21-5p induces MMT and promotes peritoneal metastasis. Gastric cancer (GC)-derived exosomes were identified by transmission electron microscopy and western blot analysis, then the uptake of exosomes was confirmed by PKH-67 staining. The expression of miR-21-5p and SMAD7 were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, and the interactions between miR-21-5p and its target genes SMAD7 were confirmed by Luciferase reporter assays. The MMT of PMCs was determined by invasion assays, adhesion assays, immunofluorescent assay, and western blot. Meanwhile, mouse model of tumor peritoneal dissemination model was performed to investigate the role of exosomal miR-21-5p in peritoneal metastasis in vivo. We found that PMCs could internalize GC-derived exosomal miR-21-5p and led to increased levels of miR-21-5p in PMCs. Through various types of in vitro and in vivo assays, we confirmed that exosomal miR-21-5p was able to induce MMT of PMCs and promote tumor peritoneal metastasis. Moreover, our study revealed that this process was promoted by exosomal miR-21-5p through activating TGF-β/Smad pathway via targeting SMAD7. Altogether, our data suggest that exosomal miR-21-5p induces MMT of PMCs and promote cancer peritoneal dissemination by targeting SMAD7. The exosomal miR-21-5p may be a novel therapeutic target for GC peritoneal metastasis.

Netrin‑1 induces the proliferation of gastric cancer cells via the ERK/MAPK signaling pathway and FAK activation

Netrin‑1 (NTN1) has been demonstrated to promote tumorigenesis in multiple types of cancer; however, its role in the growth of gastric cancer (GC) cells has not been described in detail. In the present study, the data suggested that NTN1 knockdown significantly decreased the proliferation of GC cells, whereas NTN1 overexpression had an opposing effect. Furthermore, the use of focal adhesion kinase (FAK) inhibitor decreased the proliferation of GC cells. It was also revealed that NTN1 markedly induced the phosphorylation of FAK, extracellular signal‑regulated kinase (ERK) and c‑Jun N‑terminal kinase (JNK), but did not induce the phosphorylation of P38. In addition, the expression of ERK and JNK was markedly inhibited by treatment with FAK inhibitor. Xenograft analysis using GC cells revealed that NTN1 overexpression promoted tumor growth. Furthermore, the expression of NTN1 in samples collected from nude mice was downregulated in the NTN1 knockdown group and upregulated in the NTN1 overexpression group compared with the control short hairpin RNA group. These results suggest that NTN1‑induced GC cell proliferation is mediated by activating ERK/MAPK signaling cascades via the distinct activation of FAK.

[Minimally invasive surgery for the severe degenerative lumbar scoliosis: two stage protocol]

Objective: To investigate the surgical outcome of minimally invasive surgery(MIS) for severe degenerative lumbar scoliosis(DLS) and put forward a two-stage MIS surgical strategy. Methods: Prospective study of MISDEF Ⅲ DLS patients from June 2016 to August 2017 in the Second Affiliated Hospital of Zhejiang University was carried out, excluding the patients whose apex vertebrae of scoliosis was above L(1/2) level or whose facet joint got spontaneous fusion. Fifty-three patients were included in this study for staging evaluation and MIS surgical treatment. Information was recorded, including gender, age, body mass index, follow-up period, pelvic incidence (PI), blood loss, operation time, visual analogue pain score (VAS), Oswestry disability index (ODI), complications in the perioperative period and follow-up period, and also the radiographic parameters such as scoliosis Cobb angle, the mismatch between pelvic incidence and lumbar lordosis (PI-LL), sagittalvertical axis (SVA), coronal balance (CB) before and after each stage of surgery or latest follow-up. The paired-samples t test was used to analyze the effectiveness of staging surgery. Results: Fifty-three patients (18 males and 35 females) were included in this study. All patients had completed clinical and the follow-up records, with an average follow-up period of 11.52 months (6-20 months). A total of 168 segments fusions were performed with CLIF, 113 segments were performed with anterior column realignment (ACR), the average correct angle was 15.6°±6.3°(7°-28°) in sagittal plane each level. After the stage Ⅰ surgery, lumbar scoliosis cobb had been corrected for 55.35%, after the stage Ⅱ surgery, rate of correction was 75.6%. PI-LL had been matched (-32.8°±14.9° to -2.5°±9.4°), SVA was changed from 5.7 cm to 0.6 cm, the stage Ⅰ rate of correction was 80.3 and stage Ⅱ was 88.8%, pelvic tilt (PT), lumbar lordosis (LL) and CB had been restored; 13 (24.5%) patients were performed paraspinal approach transforaminal decompression. The posterior minimally invasive fixation indexes: 11(20.8%) patients were performed paraspinal approach transforaminal multi-segment transforaminal osteotomy (TFO) and internal fixation; 36(67.92%) cases were performed paraspinal approach transforaminal multi-segment fixation; 6(11.33%) patients were treated with percutaneous pedicle screw fixation. The average fixed segments was 7.4±1.4 in each patient. The blood loss of stage Ⅰ and stage Ⅱ operation was (157±71) ml, (343±224)ml, respectively. The operation time was (214±60) min, (190±54)min respectively in the two stage operations. The low back pain and leg pain VAS score and ODI improved after the stage Ⅰ and Ⅱ surgery (t=17.948, 10.099, 14.619, all P<0.001). Conclusions: MIS for the severe degenerative lumbar scoliosis can achieve good clinical outcome and deformity correction. The two-stage protocol has the advantages of less complications and is well-tolerated.

A Genetic Variant Located in miR-146b Promoter Region Is Associated with Prognosis of Gastric Cancer

Background: SNPs in the promoter region of miRNAs have been reported to be associated with cancer prognosis. Our previous study found that miR-146b had a strong correlation with the stage classification of gastric cancer and contributed to tumor progression. The current study was aimed at investigating whether an SNP located in the promoter region of miR-146b could affect the survival rate of gastric cancer.Methods: Using bioinformatics tools, we identified one SNP (rs1536309) that is located in the miR-146b promoter. We genotyped this SNP site to assess its association with gastric cancer prognosis in 940 cases.Results: We found that the dominant model of miR-146b rs1536309 was associated with a higher survival rate of gastric cancer. The association remained significant in the subgroup analysis by age (≤60), sex (male), tumor size (≤5 cm), histologic type (diffuse), lymph node metastasis (N0), distant metastasis (M0), and TNM stage (I/II).Conclusions: Our results suggested that the miR-146b rs1536309 polymorphism may be a potential biomarker for the prognosis of gastric cancer.Impact: This is the first evidence showing that patients carrying the miR-146b-5p rs1536309 CC/CT genotypes exhibited better survival than those carrying the TT genotype, suggesting the protective effect of the C allele in the prognosis of gastric cancer. Cancer Epidemiol Biomarkers Prev; 27(7); 822-8. ©2018 AACR.

miR-424-5p promotes proliferation of gastric cancer by targeting Smad3 through TGF-β signaling pathway

MiRNAs have been reported to regulate gene expression and be associated with cancer progression. Recently, miR-424-5p was reported to play important role in a variety of tumors. However, the role and molecular mechanisms of miR-424-5p in GC (gastric cancer) remains largely unknown. In this study, we aimed to explore the role of miR-424-5p in GC. QRT-PCR was used to determine the expression levels of miR-424-5p and Smad3. CCK8 assay, plate clone assay and cell cycle assay were used to measure the effects of miR-424-5p on GC cell proliferation. Luciferase reporter assay and western blotting were used to prove that Smad3 was one of the direct targets of miR-424-5p. Tumorigenesis assay was used to investigate the role of miR-424-5p in tumor growth of GC cells in vivo. We found that miR-424-5p was up-regulated in GC tissues and cells. Over-expression of miR-424-5p could promote the proliferation of GC cells. In addition, luciferase reporter assay and western blotting assay revealed that Smad3 was a direct target of miR-424-5p. Over-expression of Smad3 could partially reverse the effects of miR-424-5p on GC cell proliferation. Our study further revealed that miR-424-5p could inhibit TGF-β signaling pathway by Smad3.

Tag SNPs of long non-coding RNA TINCR affect the genetic susceptibility to gastric cancer in a Chinese population

Tissue differentiation-inducing non-protein coding RNA (TINCR) is required for normal epidermal differentiation. TINCR is also strongly overexpressed in human gastric cancer (GC) and contributes to carcinogenesis and tumor progression. However, the association between TINCR polymorphisms and the risk of any diseases, such as GC, remains unknown. In the present study, the tag single nucleotide polymorphisms rs8113645, rs2288947, rs8105637, and rs12610531 were analyzed in 602 patients with GC and 602 age- and sex-matched controls. Polymorphisms were genotyped using TaqMan technology. Carriers of variant rs8113645 and rs2288947 alleles indicated reduced risks of GC (p = 0.003 and 0.037, respectively). A allele genotypes of rs8113645 and G allele genotypes of rs2288947 (rs8113645 GA and AA; rs2288947 AG and GG) were also significantly associated with decreased GC risk (p < 0.05). Stratification analysis displayed that the correlations between GC risk and variant genotypes of both rs8113645 and rs2288947were more evident in younger individuals, men, nonsmokers, and individuals from rural areas. We also demonstrated that rs8113645 GA+AA genotype carriers had lower TINCR mRNA expression levels compared with common genotype in both normal and GC tissues (p < 0.05). These results suggest that long non-coding RNA TINCR polymorphisms may be implicated in GC development.

A functional polymorphism in TFF1 promoter is associated with the risk and prognosis of gastric cancer

Trefoil Factor 1 (TFF1, also named pS2), which serves as the gastrointestinal mucosal protector, is known as gastric-specific tumor suppressor gene. However, the genetic variants of TFF1 are still not well studied. In our study, we aim to explore the effects of tagging single nucleotide polymorphisms (tagSNPs) of TFF1 on risk and prognosis of gastric cancer. Seven tagSNPs of TFF1 gene were first analyzed in the discovery set, which was consisted of 753 cases and 950 cancer-free controls. Then, the validation set (940 cases and 1,042 controls) was used for further evaluation. Moreover, we also tested the relation between these tagSNPs and prognosis of gastric cancer (GC). A series of experiments were performed to investigate the underlying mechanisms. We found that rs3761376 AA in the promoter region of TFF1, could reduce the expression of TFF1 by affecting the binding affinity of estrogen receptor 1 (ESR1, ERα), and thereby increased the risk of GC (1.29, 1.08-1.53). Moreover, the rs3761376 AA genotype was also found associated with worse prognosis among patients receiving 5-FU based chemotherapy after surgery (1.71, 1.18-2.48). Further functional assays demonstrated that TFF1 could increase the chemosensitivity of 5-FU by modulating NF-κB targeted genes. These results identified the effect of rs3761376 on TFF1 expression, which accounted for the correlation with susceptibility and prognosis of GC; and this genetic variant may be a potential biomarker to predict the risk and survival of GC.

MicroRNA-148a-3p enhances cisplatin cytotoxicity in gastric cancer through mitochondrial fission induction and cyto-protective autophagy suppression

Cisplatin (CDDP) resistance is a major clinical problem associated with poor prognosis in gastric cancer (GC) patients. In this study, we performed integrated analysis of TCGA data from microRNAs (miRNAs) expression matrix of GC patients who received CDDP-based chemotherapy with GEO dataset which contains differential miRNAs expression profiles in CDDP-resistant and -sensitive cell lines. We identified miR-148a-3p downregulation as a key step involved in CDDP resistance. Using a cohort consisting 105 GC patients who received CDDP-based therapy, we found that miR-148a-3p downregulation was associated with a decrease in patients' disease-free survival (DFS, P = 0.0077). A series of experiment data demonstrated that: 1) miR-148a-3p was downregulated in CDDP-resistant GC cell lines; 2) miR-148a-3p reconstitution sensitized CDDP-resistant cells to CDDP treatment through promoting mitochondrial fission and decreasing AKAP1 expression level; 3) AKAP1 played a novel role in CDDP resistance by inhibiting P53-mediated DRP1 dephosphorylation; 4) miR-148a-3p reconstitution in CDDP-resistant cells inhibits the cyto-protective autophagy by suppressing RAB12 expression and mTOR1 activation. Taken together, our study demonstrates that miR-148a-3p could be a promising prognostic marker or therapeutic candidate for overcoming CDDP resistance in GC.

Clinical Application of Circulating Tumor DNA in the Genetic Analysis of Patients with Advanced GIST

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor of digestive tract. In the past, tissue biopsy was the main method for the diagnosis of GISTs. Although, circulating tumor DNA (ctDNA) detection by next-generation sequencing (NGS) may be a feasible and replaceable method for diagnosis of GISTs. We retrospectively analyzed the data for ctDNA and tissue DNA detection from 32 advanced GIST patients. We found that NGS obviously increased the positive rate of ctDNA detection. ctDNA detection identified rare mutations that were not detected in tissue DNA detection. Tumor size and Ki-67 were significant influencing factors of the positive rate of ctDNA detection and concordance between ctDNA and tissue DNA detection. In all patients, the concordance rate between ctDNA and tissue DNA detection was 71.9%, with moderate concordance, but the concordance was strong for patients with tumor size > 10 cm or Ki-67 > 5%. Tumor size, mitotic figure, Ki-67, and ctDNA mutation type were the significant influencing factors of prognosis, but only tumor size and ctDNA mutation type, were the independent prognostic factors for advanced GIST patients. We confirmed that ctDNA detection by NGS is a feasible and promising method for the diagnosis and prognosis of advanced GIST patients. Mol Cancer Ther; 17(1); 290-6. ©2017 AACR.

[Selection and appraisal of digestive tract reconstruction after totally laparoscopic gastrectomy for gastric cancer]

In recent years, with the development of laparoscopic technology, more and more totally laparoscopic gastrectomy has been applied. The reconstruction of digestive tract is the key procedure of laparoscopic gastrectomy and is associated with the postoperative quality of life. Each method of digestive tract reconstruction has its own characteristic, however, unified consensus on how to choose the optimal method for digestive tract reconstruction has not yet been reached till today. In this article, we will discuss and evaluate the advantages, disadvantages and indications of these reconstruction methods after totally laparoscopic distal gastrectomy, total gastrectomy and proximal gastrectomy combined with relative literatures and our practical experience in order to provide the reference to choose the reasonable reconstruction method at the premise of radical resection, which may decrease the morbidity of postoperative complication, increase the quality of life, and bring benefits to patients definitely.

miR-3174 Contributes to Apoptosis and Autophagic Cell Death Defects in Gastric Cancer Cells by Targeting ARHGAP10

Gastric cancer (GC) is a major health problem worldwide because of its high morbidity and mortality. Considering the well-established roles of miRNA in the regulation of GC carcinogenesis and progression, we screened differentially expressed microRNAs (miRNAs) by using The Cancer Genome Atlas (TCGA) and the GEO databases. We found that miR-3174 was the most significantly differentially expressed miRNA in GC. Ectopic miR-3174 expression was also detected in clinical GC patient samples and cell lines and associated with poor patient prognosis. Apoptosis and autophagic cell death are two types of programmed cell death, whereas both are deficient in gastric cancer. Our functional analyses demonstrated that miR-3174 inhibited mitochondria-dependent apoptosis and autophagic cell death in GC. Moreover, high expression of miR-3174 also resulted in Cisplatin resistance in GC cells. Using bioinformatics analyses combined with in vitro and in vivo experiments, we determined that miR-3174 directly targets ARHGAP10. Notably, ARHGAP10 promoted mitochondria-dependent apoptosis by enhancing p53 expression, which was followed by Bax trans-activation and caspase cleavage. ARHGAP10 also facilitated autophagic cell death by suppressing mammalian target of rapamycin complex 1 (mTOC1) activity. Our results reveal a potential miRNA-based clinical therapeutic target that may also serve as a predictive marker for GC.

Identification of a synonymous variant in TRIM59 gene for gastric cancer risk in a Chinese population

Tripartite motif 59 (TRIM59) is a novel oncogenic driver in gastric cancer (GC) that is implicated in disease progression as well as dismal survival. Genetic variants in peculiar gene are likely candidates for conferring hereditary susceptibility. The role of TRIM59 polymorphism in predicting the risk of malignant diseases and its relevance to TRIM59 expression have not been discussed. Using a HapMap tagSNPs approach, we screened three tag TRIM59 single nucleotide polymorphisms (SNPs) (rs1141023G>A, rs7629A>G, rs11706810T>C) which were genotyped in 602 GC patients and 868 healthy controls. Our study provided convincing result that carries of variant rs1141023A allele markedly increased GC risk (P=0.006). In comparison with the GG homozygotes, the variant GA heterozygotes demonstrated 1.50-fold elevated risk of GC (p=0.014, 95% confidence interval [CI] = 1.09–2.08). Subjects who carried the (GA+AA) genotypes of rs1141023 were associated with remarkable increased GC risk compared with the common genotype (P = 0.013, adjusted OR = 1.50, 95% CI = 1.09–2.05). Further stratified analyses displayed that the relationship between mutant genotype of rs1141023 and GC risk was more profound in male individuals. Intriguingly, there is no significant distinction of TRIM59 mRNA expression between rs1141023GA genotype and GG genotype in 44 normal gastric tissues. Taken together, our results suggest that rs1141023 polymorphism contributes to increased predisposition to GC and thus may be responsible for predicting early GC.

The Role of Tumoral FOXP3 on Cell Proliferation, Migration, and Invasion in Gastric Cancer

BACKGROUND/AIMS

There is little published data on the role of FOXP3 in gastric cancer.

METHODS

FOXP3 expression and localization in gastric cancer tissues and cells were examined by immunohistochemistry, RT-PCR, flow cytometry, western blot, and laser confocal microscopy. CCK8, plate clone, wound healing, and transwell insert assays were performed for gastric cancer cells. Potential molecules and signaling pathways were screened using high-throughput transcriptome sequencing.

RESULTS

FOXP3 expression in gastric cancer tissues was higher than that in para-carcinoma tissues. It was restricted to the cytoplasm of para-carcinoma tissues, but was observed in the cytoplasm or/and nuclei of gastric cancer tissues. FOXP3 expression was positively correlated with pathological grading, and was detected in gastric cancer and GES-1 cells, where it was expressed in the cytoplasm alone, or in both the cytoplasm and the nucleus. FOXP3 overexpression promoted cell proliferation, migration, and invasion, while FOXP3 knockdown suppressed these effects. Furthermore, RT-PCR and ELISA confirmed that FOXP3 upregulation resulted in increased TGF-β expression and secretion in gastric cancer cells.

CONCLUSION

FOXP3 expression was associated with degree of gastric cancer differentiation. In addition, upregulated and ectopic tumoral FOXP3 can promote gastric cancer proliferation, migration, and invasion, partly through the TGF-β pathway.

Silencing of AQP3 induces apoptosis of gastric cancer cells via downregulation of glycerol intake and downstream inhibition of lipogenesis and autophagy

Gastric cancer (GC) has a poor prognosis and is a leading cause of cancer-related death. Optimal therapeutic targets have not been identified. AQP3 is capable of transporting glycerol across the cytomembrane. Previous studies have shown that AQP3 is involved in proliferation, invasion and migration by regulating glycerol and lipid metabolism in diverse cancer cell types. However, the potential roles of glycerol and lipid metabolism in AQP3-related cell apoptosis in GC remain unclear. In this study, we observed that AQP3 expression was upregulated in tumor tissues, and positively correlated with tumor size, lymph node metastasis and glycerol concentration in human GC samples. Silencing of AQP3 resulted in decreased glycerol intake and impaired lipid synthesis, which contributed to increased cell apoptosis. Furthermore, inhibition of autophagy induced by AQP3 knockdown promoted cell apoptosis. Administration of either glycerol or rapamycin restored cell viability, and overexpression of AQP3 increased cell viability by upregulating cellular glycerol metabolism and autophagy. Our study demonstrates that the increase in cell apoptosis of AQP3-deficient GC cells is a consequence of reduced glycerol uptake and lipogenesis and is associated with autophagy inhibition induced by AQP3 deficiency.

Risk factors associated with early postoperative complications following laparoscopic total gastrectomy: Experience from the Chinese Laparoscopic Gastrointestinal Surgery Study (CLASS) group

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Background: The incidence rate of proximal gastric cancer has been rising steadily, and laparoscopic total gastrectomy (LTG) has been widely adopted. However, the safety of LTG still lacks solid evidence to prove. The aim of this study was to evaluate morbidity and mortality of LTG, and determine the risk factors associated with early postoperative complications. Methods: A retrospective multicenter study was carried out in China, and medical records of 109 gastric cancer patients receiving LTG during September 2014 and June 2016 were retrieved from the database. Patient characteristics, surgical outcomes, and postoperative morbidities and mortalities were analyzed. Results: Morbidity and mortality rates were 22.0% and 0% respectively. Pulmonary infection (13.8%, n = 15) was the most common complication. Most complications were grade II (15.5%, n = 17) according to the Clavien-Dindo classification. Multivariable analysis identified comorbidity, type of reconstruction method (TLTG) were independent risk factors of early postoperative complications. Comorbidity was the only independent risk factor of complications graded more than II. Diabetes mellitus was found correlated with surgical complication in subgroup analysis. Conclusions: LTG is safe and technically feasible in treating gastric cancer. Careful selection of patients without comorbidity and applying laparoscopy-assisted total gastrectomy instead of totally laparoscopic total gastrectomy may decrease postoperative complications.