Recent insights in the therapeutic management of patients with gastric cancer

Daily practices in chemotherapy for advanced gastric or gastroesophageal junction adenocarcinoma: METESTOMAC French prospective cohort

BACKGROUND

Around 50% of gastric cancers are diagnosed at an advanced stage. Several chemotherapy regimens are now internationally validated. Few data are available on the routine daily management of advanced gastric or gastroesophageal junction cancers. We aimed to describe chemotherapy practices, tolerance, and efficacy overall survival (OS) and Progression free survival (PFS) in a prospective French cohort.

METHODS

Patients starting palliative chemotherapy were prospectively enrolled in 49 French centres. The primary objective was to report and describe patients' characteristics and treatment strategies. Secondary objectives were OS, PFS, objective response rate, adverse events rate, performance status deterioration during the chemotherapy.

RESULTS

A total of 182 patients were included; 179 were analysed. Most patients received platinium-based chemotherapy as the first treatment and FOLFIRI as second; 62.0% of patients received a second line, and 32.4% a third line. More than two thirds of Her2-positive patients were first treated with trastuzumab. The FOLFIRI regimen was the most frequently used second-line therapy. Median OS was 13.3 months, similar whatever the chemotherapy or combinations used in the first line. One- and 2-year OS increased with the number of chemotherapy lines received, from respectively 24.7% and 5.7% (1 line), to 46.9% and 12.4% (2 lines) and 88.1% and 29.9% (3 or more lines) (p < 0.0001).

CONCLUSION

Our study showed that treatment strategies in France are based on a succession of doublets, making it possible to offer a second and third line of treatment more often. This treatment strategy must be taken into account for future trials with immunotherapy combinations.

Reticulon 2 promotes gastric cancer metastasis via activating endoplasmic reticulum Ca2+ efflux-mediated ERK signalling

Gastric cancer ranks fourth for mortality globally among various malignant tumours, and invasion and metastasis are the major reason leading to its poor prognosis. Recently, accumulating studies revealed the role of reticulon proteins in cell growth and transmigration. However, the expression and biological function of reticulon proteins in human gastric cancer remain largely unclear. Herein, we explored the potential role of reticulon 2 (RTN2) in the progression of gastric cancer. Tissue microarray was used to determine the expression levels of RTN2 in 267 gastric cancer patients by immunohistochemistry. Gastric cancer cell lines were utilised to examine the influences of RTN2 on cellular migration and invasion abilities, epithelial-to-mesenchymal transition (EMT) and signalling pathway. In vivo studies were also performed to detect the effect of RTN2 on tumour metastasis. We found that RTN2 expression was notably upregulated in tumour tissues compared to pericarcinomatous tissues. High RTN2 expression was positively correlated with patients’ age, vessel invasion, tumour invasion depth, lymph node metastasis and TNM stage. Besides, high RTN2 staining intensity was associated with adverse survival which was further identified as an independent prognostic factor for gastric cancer patients by multivariate analysis. And the predictive accuracy was also improved when incorporated RTN2 into the TNM-staging system. RTN2 could promote the proliferation, migration and invasion of gastric cancer cells in vitro and lung metastasis in vivo. Mechanistically, RTN2 interacted with IP3R, and activated ERK signalling pathway via facilitating Ca²⁺ release from the endoplasmic reticulum, and subsequently drove EMT in gastric cancer cells. These results proposed RTN2 as a novel promotor and potential molecular target for gastric cancer therapies.

Long non-coding RNA CCL2 promoted gastric cancer function via miR-128/ PARP2 signal pathway

Amounts of studies have revealed long non-coding RNA (lncRNA) was related to the development of gastric cancer. Here, our results suggested the function and regulatory mechanism of CCL2 in gastric cancer. Quantitative polymerase-chain reaction (qPCR) was employed to inspect lncRNA CCL2 and miR-128 expression in normal gastric cell line (GES-1) and tumor cell lines (HGC-27 and MKN-45). The effects of CCL2 and miR-128 were measured via Luciferase reporter test. Western blot was used to check PARP2 protein expression. CCL2 expression and PARP2 protein levels were up-regulated, while miR-128 expression was obviously lower. Meanwhile, CCL2 down-regulating significantly repressed the proliferation, migration, and invasion by regulating miR-128. In addition, we proved miR-128 was a direct target of CCL2 through double luciferase assay and bioinformatics analysis. Moreover, miR-128 markedly inhibited the proliferation, migration, and invasion in gastric cancer. More importantly, miR-128 could reverse the effects of lncRNA CCL2 knocked down. PARP2-si obviously suppressed in gastric cancer proliferation, migration, and invasion. Meanwhile, miR-128 mimic and the knockout of CCL2 distinctly decreased PARP2 protein level. Additionally, luciferase report experiments certificated that PARP2 targeted miR-128, implying PARP2 directly interacted with miR-128 in gastric cancer. More interestingly, the downregulation of PARP could reverse the trend triggered by miR-128 inhibitor in gastric tumor. All over these results showed lncRNA CCL2 played importance of role in gastric tumor via miR-128/PARP2 axis signal pathway. LncRNA CCL2 accelerated gastric cancer progression by regulating miR-128/PARP2 signaling pathway, providing a novel possible strategy for the treatment of gastric cancer.

RNA-binding protein RNPC1 acts as an oncogene in gastric cancer by stabilizing aurora kinase B mRNA

BACKGROUND

RNPC1 is reported to act as a tumor suppressor by binding and regulating the expression of target genes in various cancers. However, the role of RNPC1 in gastric cancer and the underlying mechanisms are still unclear.

METHODS

Gastric cancer cells were stably transfected with lentivirus. Proliferation, migration, invasion, cell cycle in vitro and tumorigenesis in vivo were used to assess the role of RNPC1. Quantitative real-time PCR, western blotting and immunohistochemistry were used to detect the relationship between RNPC1 and aurora kinase B (AURKB). RNA immunoprecipitation (RIP), RNA electrophoretic mobility shift assays (REMSAs), and dual-luciferase reporter assays were used to identify the direct binding sites of RNPC1 with AURKB mRNA. A CCK-8 assay was conducted to confirm the function of AURKB in RNPC1-induced growth promotion.

RESULTS

High RNPC1 expression was found in gastric cancer tissues and cell lines and was associated with high TNM stage. RNPC1 overexpression significantly promoted the proliferation, migration, and invasion of gastric cancer cells. Knockdown of RNPC1 could impede gastric cancer tumorigenesis in nude mice. AURKB expression was positively related to RNPC1. RNPC1 directly binds to the 3'-untranslated region (3'-UTR) of AURKB and enhances AURKB mRNA stability. AURKB reversed the proliferation induced by RNPC1 in gastric cancer cells. RNPC1 resulted in mitotic defects, aneuploidy and chromosomal instability in gastric cancer cells, similar to AURKB.

CONCLUSION

RNPC1 acts as an oncogene in gastric cancer by influencing cell mitosis by increasing AURKB mRNA stability, which may provide a potential biomarker and a therapeutic target for gastric cancer.

Circular RNA PTK2 Accelerates Cell Proliferation and Inhibits Cell Apoptosis in Gastric Carcinoma via miR-139-3p

BACKGROUND

Gastric carcinoma (GC) is one of the most common malignant tumors. Although increasing studies have indicated that circular RNAs function as ideal biomarkers for multiple cancers, only a few researches elucidated the correlation between circular RNA PTK2 (circPTK2) and human cancers.

AIM

To further explore the expression status, biological function, and regulatory mechanism of circPTK2 in GC.

METHODS

Bioinformatics analysis and function or mechanism experiments including RT-qPCR, flow cytometry, Western blot, luciferase reporter assay, and xenografts assays were applied to investigate the function of circPTK2 and miR-139-3p.

RESULTS

High expression of circPTK2 was presented in GC tissues and cells. The circPTK2 knockdown notably suppressed cell proliferation and promoted cell apoptosis in GC. In mechanism, circPTK2 served as a sponge of miR-139-3p. Inhibition of miR-139-3p could reverse circPTK2 silence-mediated effects on GC cell proliferation and apoptosis. Furthermore, the xenograft tumor model was established to investigate the role of circPTK2 in GC tumor growth. Experimental results delineated that the reduction in tumor growth in response to circPTK2 knockdown was partly recovered by miR-139-3p inhibitor.

CONCLUSIONS

CircPTK2 promotes GC development by sponging miR-139-3p, which may function as an effective gene target for managing GC.

Impact of follow-up on generalized pairwise comparisons for estimating the irinotecan benefit in advanced/metastatic gastric cancer

BACKGROUND AND OBJECTIVES

The net treatment effect (∆) is a new method to assess the treatment benefit that combines multiple time-to-event, binary and continuous endpoints according to a pre-specified sequence. It represents the net probability for a random patient treated in the experimental arm to have a better overall outcome than a random patient from the control arm does. We aimed at characterizing the impact of follow-up on ∆ estimated from both time-to-event and binary toxicity endpoints, in randomized controlled trials (RCTs) of irinotecan-based regimen in advanced/metastatic gastric cancer (AGC).

STUDY DESIGN

Three RCTs are reanalysed. The net treatment effect using from one to three outcomes (i.e. overall survival, time to progression and toxicity in this order) and the hazard ratio (HR) were estimated after various cut-off dates and compared to the values obtained after complete follow-up were reported.

RESULTS

In all three RCTs (897 patients), the irinotecan-based regimen was superior to the non-irinotecan containing regimen in terms of HR and ∆. This superiority was lower when the net treatment effect also accounted for toxicity. The HR was slightly less influenced by an incomplete follow-up than ∆ was, but correction proposed by Péron to account for censored observations showed quite robust results.

CONCLUSIONS

The net treatment effect using Péron's correction can be used in case of interim analyses or high censoring rates. In addition to relative measures such as the hazard ratio, it provides a simple mean to evaluate the net treatment effect with and without toxicity outcomes.

SATB1-Mediated Upregulation of the Oncogenic Receptor Tyrosine Kinase HER3 Antagonizes MET Inhibition in Gastric Cancer Cells

MET-amplified gastric cancer cells are extremely sensitive to MET inhibition in vitro, whereas clinical efficacy of MET inhibitors is disappointing. The compensatory activation of other oncogenic growth factor receptors may serve as an underlying mechanism of resistance. In this study, we analyzed the role of HER receptors, in particular HER3 and its ligand heregulin, in this respect. This also included the chromatin-organizer protein SATB1, as an established regulator of HER expression in other tumor entities. In a panel of MET-amplified gastric carcinoma cell lines, cell growth under anchorage-dependent and independent conditions was studied upon inhibitor treatment or siRNA-mediated knockdown. Expression analyses were performed using RT-qPCR, FACS, and immunoblots. Signal transduction was monitored via antibody arrays and immunoblots. As expected, MET inhibition led to a growth arrest and inhibition of MAPK signaling. Strikingly, however, this was accompanied by a rapid and profound upregulation of the oncogenic receptor HER3. This finding was determined as functionally relevant, since HER3 activation by HRG led to partial MET inhibitor resistance, and MAPK/Akt signaling was even found enhanced upon HRG+MET inhibitor treatment compared to HRG alone. SATB1 was identified as mediator of HER3 upregulation. Concomitantly, SATB1 knockdown prevented upregulation of HER3, thus abrogating the HRG-promoted rescue from MET inhibition. Taken together, our results introduce the combined HER3/MET inhibition as strategy to overcome resistance towards MET inhibitors.

Long non-coding RNA SNHG3, induced by IL-6/STAT3 transactivation, promotes stem cell-like properties of gastric cancer cells by regulating the miR-3619-5p/ARL2 axis

BACKGROUND

Chemotherapy is, next to surgery and radiotherapy, the mainstay regimen for the clinical management of gastric cancer. This therapy is, however, heavily compromised by the acquisition of resistance. Here, we aimed to clarify the potential involvement of long non-coding RNA SNGH3 in the acquisition of cisplatin resistance and stemness in gastric cancer.

METHODS

Cell viability and proliferation were measured using Cell Counting Kit-8 and colony formation assays, respectively. Stem cell-like cell growth was evaluated using a mammosphere formation assay. RNA levels of SNHG2, OCT-4, SOX-2, CD44, miR-3619-5p and ARL2 were determined using qRT-PCR, whereas protein levels of OCT-4, SOX-2, CD44, ARL2, STAT3 and pSTAT3 were determined using Western blotting. Dual luciferase reporter assays were employed to interrogate regulatory interactions between STAT3, SNHG3, miR-3619-5p and ARL2, respectively. Direct binding of STAT3 to the SNHG3 promoter was investigated using a chromatin immunoprecipitation assay.

RESULTS

We found that IL-6 triggered stem cell-like properties in cisplatin-treated gastric cancer cells and activated STAT3, which in turn transcriptionally regulated SNHG3 expression. SNHG3 expression up-regulation positively correlated with cisplatin resistance and stemness of gastric cancer cells, while SNHG3 down-regulation inhibited stem cell-like properties. In addition, we found that SNHG3 up-regulated ARL2 expression through sponging miR-3619-5p, which predominantly mediated the oncogenic properties of SNHG3 in this disease.

CONCLUSIONS

Our data indicate an involvement of aberrant SNHG3 over-expression in the acquisition of both cisplatin resistance and stemness of gastric cancer cells, and of the IL-6/STAT3/SNHG3/miR-3619-5p/ARL2 signaling cascade in the oncogenic properties of SNHG3.

COL4A family: potential prognostic biomarkers and therapeutic targets for gastric cancer

Background

The type IV collagen alpha chain (COL4A) family is a major component of the basement membrane (BM) that has recently been found to be involved in tumor angiogenesis and progression. However, the expression levels and the exact roles of distinct COL4A family members in gastric cancer (GC) have not been completely understood.

Methods

Here, the expression levels of COL4As in GC and normal gastric tissues were calculated by using TCGA datasets and the predicted prognostic values by the GEPIA tool. Furthermore, the cBioPortal and Metascape tools were integrated to analyze the genetic alterations, correlations and potential functions of COL4As, and their frequently altered neighboring genes in GC.

Results

Notably, the expression levels of COL4A1/2/4 in GC were higher to those in normal gastric tissues, while the expression levels of COL4A3/5/6 were lower in GC than normal. Survival analysis revealed that lower expression levels of COL4A1/5 led to higher overall survival (OS) rate. Multivariate analysis using the Cox proportional-hazards model indicated that age, gender, pathological grade, metastasis and COL4A5 expression, are independent prognostic factors for OS. However, TNM stage, lymph node metastasis, Lauren’s classification, COL4A1-4 and COL4A6 were associated with poor OS but not independent prognostic factors. Function-enriched analysis of COL4As and their frequently altered neighboring genes was involved in tumor proliferation and metastasis in GC.

Conclusions

These results implied that COL4A1/2 were potential therapeutic targets for GC. COL4A3/4/6 might have an impact on gastric carcinogenesis and subsequent progression, whereas COL4A5 was an independent prognostic marker for GC.

RYK, a receptor of noncanonical Wnt ligand Wnt5a, is positively correlated with gastric cancer tumorigenesis and potential of liver metastasis

Gastric cancer (GC) is the most prevalent human cancer around the globe. In GC, Wnt signaling is deregulated, and receptor-like tyrosine kinase (RYK) coreceptors have been identified to interact with noncanonical Wnt ligand Wnt5a. We, therefore, aimed to evaluate the role of RYK in GC development and metastasis. GC tumor samples were collected from 250 GC patients. Expressions of RYK, as well as markers for the epithelial-mesenchymal transition (EMT), such as N-cadherin and E-cadherin, were subjected to correlation analysis with clinicopathological features. Endogenous RYK expression levels were compared in GC cell lines with ascending metastatic potentials followed by stable RYK knockdown. Effect of RYK knockdown on GC cell migration, invasion, and EMT phenotype were assessed in vitro, and on GC tumor growth in vivo in a xenograft rodent model. Particularly, liver metastasis potential of tail vein-injected GC cells was also analyzed following RYK knockdown. RYK was highly correlated with liver metastasis of GC tumors and the expression profiles of EMT markers toward the mesenchymal tendency. RYK expression was also positively correlated with the metastasis potential of GC cells. RYK knockdown not only inhibited migration, invasion, and EMT of GC cells in vitro, but also suppressed tumorigenesis and liver metastasis of GC cells in vivo using the mouse xenograft model. RYK is highly correlated with GC tumorigenesis and potential of liver metastasis, suggesting it may be a novel oncogenic factor of the noncanonical Wnt signaling pathway contributing to GC.NEW & NOTEWORTHY RYK is highly correlated with gastric cancer tumorigenesis and the potential of liver metastasis, suggesting it may be a novel oncogenic factor of the noncanonical Wnt signaling pathway contributing to gastric cancer.

The positive feedback loop of RHPN1-AS1/miR-1299/ETS1 accelerates the deterioration of gastric cancer

Gastric cancer (GC) is the most prevailing malignant tumor of digestive tract and accounts for a considerable part of cancer-relevant deaths worldwide. An increasing number of literatures highlight the important role of lncRNAs in the occurrence and development of GC. Considering that the function of RHPN1-AS1 in GC remains to be fully inquired, we purposed to investigate the potential and mechanism of RHPN1-AS1 in GC. The expression of RHPN1-AS1 was significantly upregulated in GC samples and cells. High RHPN1-AS1 level was strongly correlated with advanced stages of GC and predicted poor outcomes of GC. Furthermore, depletion of RHPN1-AS1 inhibited cell proliferation and cell cycle whereas promoted cell apoptosis. Subcellular fractionation analysis expounded the main expression of RHPN1-AS1 in GC cell cytoplasm. Herein, we conjectured that RHPN1-AS1 might exert its performance in GC through the ceRNA network. Our findings demonstrated that RHPN1-AS1 enhanced ETS1 expression via sponging miR-1299. More importantly, the transcriptional activation of RHPN1-AS1 was mediated by ETS1. Results of recue assays validated that RHPN1-AS1/miR-1299/ETS1 positive feedback loop aggravated the malignant behaviors of GC, revealing RHPN1-AS1 as a latent effective target for the treatment of GC patients.

Long non-coding RNA SNHG3 promotes progression of gastric cancer by regulating neighboring MED18 gene methylation

To understand the mechanistic involvement of long non-coding RNA (lncRNA) SNHG3 in gastric cancer (GC), the relative abundance of SNHG3 was determined by real-time PCR. Overall and metastasis-free survival was analyzed by Kaplan–Meier’s plot. The potential impact of SNHG3 on tumor progression was evaluated both in vitro and in vivo. The in vivo metastasis was monitored in the tail vein-injected mice. Our data suggested that high SNHG3 associated with unfavorable prognosis in respect to overall and metastasis-free survival. SNHG3-deficiency significantly suppressed cell proliferation and cell viability in vitro and xenograft progression in vivo. In addition, ectopic overexpression of SNHG3 promoted cell migration and invasion in vitro and lung metastasis in vivo. Mechanistically, we uncovered SNHG3 associated with EZH2 and negatively regulated MED18 expression through methylation modulation. Transient knockdown of MED18 in SNHG3-deficient cells completely rescued the tumor suppressive phenotypes in GC cells. Our data unraveled the oncogenic properties of high SNHG3 in GC, which predominantly depended on epigenetically regulated MED18.

Salidroside inhibits the proliferation and migration of gastric carcinoma cells and tumor growth via the activation of ERS-dependent autophagy and apoptosis

The endoplasmic reticulum stress (ERS)-induced autophagy and apoptosis are favorable for the suppression of many cancer types. Salidroside (Salid) has been proven to be capable of inducing the apoptosis of many cancer cells. However, the underlying mechanisms and whether Salid can activate the autophagic system have still not been explained thoroughly. Herein, the inhibition effect of Salid on the growth and progress of gastric cancer and the underlying mechanisms were investigated. With the SGC-7901 cells acting as the cancer model cells, we ascertained that Salid exerted a superior antagonism effect on the growth and migration of gastric cancer cells in a dose-dependent manner. Additionally, Salid exhibited strong capacity to induce cell apoptosis by the down-regulation of proliferation-related genes (Ki67 and PCNA), increase in the pro-apoptotic protein C-caspase-3, and changing the levels of other related genes. A mechanism study revealed that the levels of the ERS-related genes, such as CHOP, C-caspase-12, GADD34, and BiP, in the SGC-7901 cells dramatically changed post-treatment by Salid, indicating the involvement of ERS in Salid-inducing cell apoptosis. In addition, the increased LC3⁺ autophagic vacuoles, enhanced conversion of LC3-I to LC3-II, and inhibition of the PI3K/Akt/mTOR pathway further confirmed the activation of autophagy induced by Salid. Importantly, the effect of Salid in regulating the levels of autophagy-related proteins or the signaling pathway could be markedly depressed by co-incubating with Wortmannin (Wort), an autophagy inhibitor. The final evaluation of the tumor therapy efficacy exhibited satisfactory cancer growth inhibition by Salid with negligible toxicity to normal tissues. In summary, the present work provides a comprehensive effective evaluation of Salid for treating gastric cancer. The detailed investigation of the underlying mechanisms may offer a rational reference for the future applications of Salid in clinic.

The endoplasmic reticulum stress (ERS)-induced autophagy and apoptosis are favorable for the suppression of many cancer types.

Postoperative intraperitoneal hyperthermic perfusion improve survival for advanced gastric cancer

To evaluate the value of intraperitoneal hyperthermic perfusion (IPHP) in the treatment of gastric cancer.Gastric cancer (GC) is a malignancy with poor prognosis, recent years have demonstrated advances in the use of IPHP for the treatment of advanced gastric cancer (AGC), but the outcome is controversial.Between January 2015 and January 2017, 134 patients with GC were treated with IPHP in our surgery department, 130 of them were advanced GC patients, and other 1439 cases were treated without IPHP for comparison. In this retrospective cohort study, demographic, perioperative data, and follow-up data were analyzed by univariant analysis, Kaplan-Meier and Cox regression survival analysis.We found the 1-year survival in IPHP group was significantly longer than it in non-IPHP group (85.5% vs 73.8%, P = .027). and IPHP decreased mortality 1.8 times in 2-year course (OR = 0.556, P = .004). The incidence rate of total complications in IPHP group was similar to that in the Non-IPHP group (6.67% vs 7.46%, respectively; P = .718). We classified all patients into four groups, operation alone, operation + chemotherapy, operation + IPHP, and operation + IPHP + chemotherapy. The 1-year survival in the groups was 70.2%, 77.5%, 83.1%, and 93.5%, respectively (P = .001), compared with the group of operation alone, the 2-year mortality risk was decreased 1.76 times (OR = 0.569, P = .030) and 2.59 times (OR = 0.385, P = .022) in operation + IPHP group and operation + IPHP + chemotherapy group.Our results suggest that IPHP could contribute to improve survival of patients with gastric cancer. And the modality of operation + IPHP + chemotherapy is the optimal treatment modality for gastric cancer.

Ribophorin II potentiates P-glycoprotein- and ABCG2-mediated multidrug resistance via activating ERK pathway in gastric cancer

Multidrug resistance (MDR) is a critical reason of cancer chemotherapy failure. Ribophorin II (RPN2) has emerged as a vital regulator of MDR in multiple cancers including gastric cancer (GC). However, the roles and molecular mechanisms of RPN2 in MDR have not been well featured till now. The present study aimed to explore the roles and molecular mechanisms of RPN2 in MDR of drug-resistant GC cells. Results showed that the expressions of RPN2, multidrug resistance 1 (MDR1), and ATP binding cassette subfamily G member 2 (ABCG2) were upregulated in SGC7901/DDP and SGC7901/VCR cells. Knockdown of RPN2 alleviated MDR through downregulating MDR1 and ABCG2 expressions in SGC7901/DDP and SGC7901/VCR cells. RPN2 depletion inhibited the activation of MEK/ERK pathway. RPN2 overexpression enhanced MDR by upregulating P-glycoprotein (P-gp) and ABCG2 protein expressions in SGC7901/DDP or SGC7901/VCR cells, while this effect of RPN2 was abrogated by ERK knockdown or treatment with ERK inhibitor PD98059. Our findings suggested that RPN2 potentiated P-gp- and ABCG2-mediated MDR via activating MEK/ERK pathway in GC, hinting the critical values of RPN2 in ameliorating MDR and providing a promising target for GC therapy.

A Case of Complete Remission from Advanced Gastric Adenocarcinoma with Synchronous Liver Metastasis in Response to EOX Chemotherapy

Gastric cancer is a malignant tumor with a high degree of malignancy. Multiple liver metastases from gastric cancer (LMGCs) are common. However, the treatment of LMGCs is very difficult. It is rare to achieve complete remission (CR) and long-term survival after treatment. We present the case of a patient with gastric adenocarcinoma and multiple liver metastases who showed CR for more than 33 months after perioperative EOX (epirubicin, oxaliplatin, and capecitabine) combination chemotherapy with radical distal gastrectomy and resection of liver metastases. The patient is still in follow-up without tumor recurrence. These findings suggest that LMGC does not necessarily mean a poor prognosis; preoperative chemotherapy combined with surgery may be a good treatment option for LMGC in selected patients. Further studies are needed to support this treatment approach.

Knockdown of linc00152 inhibits the progression of gastric cancer by regulating microRNA-193b-3p/ETS1 axis

BACKGROUND

Gastric cancer (GC) is a serious threat for public health worldwide. Long non-coding RNA (lncRNA) linc00152 has been well reported to be an oncogene and a potential biomarker in multiple cancers including GC. However, the molecular mechanisms of linc00152 in GC development need to be further investigated.

METHODS

RT-qPCR assay was employed to detect the levels of linc00152, microRNA-193b-3p (miR-193b-3p) and ETS1 mRNA. ETS1 protein level was measured by western blot assay. Cell proliferative, migratory and invasive capacities were assessed by colony formation together with CCK-8 assays, transwell migration and invasion assays, respectively. Bioinformatics analyses and luciferase reporter assay were used to explore whether miR-193b-3p could interact with linc00152 or ETS1 3'UTR. The roles and molecular basis of linc00152 silence on the growth of GC xenograft tumors were tested in vivo.

RESULTS

Linc00152 expression was notably upregulated in GC tissues and cells. The proliferative, migratory and invasive abilities of GC cells were weakened by linc00152 depletion, miR-193b-3p overexpression or ETS1 knockdown. Linc00152 upregulation inhibited miR-193b-3p expression by direct interaction and abolished miR-193b-3p-mediated anti-proliferation, anti-migration and anti-invasion effects in GC cells. ETS1 was a target of miR-193b-3p and linc00152 could promote ETS1 expression by downregulating miR-193b-3p. In vivo experiments further validated that linc00152 knockdown inhibited the growth of GC xenograft tumors by upregulating miR-193b-3p and downregulating ETS1.

CONCLUSION

Knockdown of linc00152 inhibited GC progression by sequestering miR-193b-3p from ETS1 in vitro and in vivo, elucidating a novel molecular mechanism of linc00152 in promoting GC carcinogenesis.

Effects of miR‑138‑5p and miR‑204‑5p on the migration and proliferation of gastric cancer cells by targeting EGFR

GC (gastric cancer) remains one of the most lethal malignancies worldwide. EGFR (epidermal growth factor receptor) plays an important role in the malignant process of GC, therefore, the present study addressed the relationship between EGFR and its potential regulators and examined their regulatory mechanisms in GC. We examined differences in the expression levels of EGFR in GC and adjacent non‑cancerous tissues. Bioinformatics analyses and dual luciferase reporter assays were used to confirm the putative relationship between miR‑138 or miR‑204 and EGFR, and their relationship was further detected using western blotting, RT‑PCR, and a series of cell studies. EGFR proteins were abundantly expressed in GC tissues, however EGFR mRNA levels remained indistinctive. Consequently, EGFR was revealed as a putative target of miR‑138 and miR‑204 which bound to the 3'UTR of EGFR mRNA. Further analysis revealed that miR‑138 and miR‑204 were significantly downregulated in GC tissues and the overexpression of miR‑138 and miR‑204 in GC cell lines resulted in the significant inhibition of EGFR protein levels and GC cell proliferation and metastasis. Rescue experiments confirmed that the roles of the two microRNAs were specific to EGFR. EGFR is a pivotal oncogene in GC progression that may be regulated by miR‑138 and miR‑204.

Inhibitory effects of CP on the growth of human gastric adenocarcinoma BGC-823 tumours in nude mice

Objective

To investigate the potential antitumour effects of [2-(6-amino-purine-9-yl)-1-hydroxy-phosphine acyl ethyl] phosphonic acid (CP) against gastric adenocarcinoma.

Methods

Human BGC-823 xenotransplants were established in nude mice. Animals were randomly divided into control and CP groups, which were administered NaHCO₃ vehicle alone or CP dissolved in NaHCO₃ (200 µg/kg body weight) daily, respectively. Tumour volume was measured weekly for 6 weeks. Resected tumours were assayed for proliferative activity with anti-Ki-67 or anti-proliferating cell nuclear antigen (PCNA) antibodies. Cell apoptosis was examined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assays and with caspase-3 immunostaining. Proteins were measured by Western blotting.

Results

There was a significant reduction in tumour volume and a reduced percentage of Ki-67-positive or PCNA-positive cells in the CP group compared with the control group. The percentage of TUNEL-positive or caspase 3-positive cells significantly increased following CP treatment compared with the control group. Tumours from the CP group had higher levels of phosphorylated-extracellular signal-regulated kinase (p-ERK) and phosphorylated-AKT (p-AKT) compared with control tumours.

Conclusion

CP treatment inhibited tumour growth and induced tumour cell apoptosis in a nude mouse model of BGC-823 gastric adenocarcinoma. Activation of the AKT and ERK signalling pathways may mediate this antitumour activity.

The relative efficacy and safety of targeted agents used in combination with chemotherapy in treating patients with untreated advanced gastric cancer: a network meta-analysis

Gastric cancer is one of the leading mortal causes. Targeted therapy is a new type of cancer treatment, which precisely identifies and attacks cancer cells and significantly reduces side effects. In this network meta-analysis, we focused on the efficacy and safety of 12 targeted agents on gastric cancer among a total of 8,405 patients from 24 trials. Hazard ratio (HR) with 95% credible interval (CrI) were calculated for primary outcomes, including overall survival (OS) and progression-free survival (PFS), while odds ratio (OR) with 95% CrI were calculated for secondary outcomes. Surface under the cumulative ranking curve (SUCRA) were calculated to illustrate the rank probability of various agents for different outcomes. Compared with other analyzed treatments, ramucirumab is outstanding in survival outcomes. However, higher risk of hematological events should be noted during its application. Lapatinib is also efficacious in progression reduction, while it is always combined with severe gastrointestinal events. Trastuzumab is proposed for its high efficacy in improving survival rate and safety, which is proper for most patients. In conclusion, trastuzumab was recommended as the optimal targeted agent combined with chemotherapy for gastric cancer patients.

TRPM2 channel-mediated regulation of autophagy maintains mitochondrial function and promotes gastric cancer cell survival via the JNK-signaling pathway

A lack of effective treatment is one of the main factors contributing to gastric cancer-related death. Discovering effective targets and understanding their underlying anti-cancer mechanism are key to achieving the best response to treatment and to limiting side effects. Although recent studies have shown that the cation channel transient receptor potential melastatin-2 (TRPM2) is crucial for cancer cell survival, the exact mechanism remains unclear, limiting its therapeutic potential. Here, using molecular and functional assays, we investigated the role of TRPM2 in survival of gastric cancer cells. Our results indicated that TRPM2 knockdown in AGS and MKN-45 cells decreases cell proliferation and enhances apoptosis. We also observed that the TRPM2 knockdown impairs mitochondrial metabolism, indicated by a decrease in basal and maximal mitochondrial oxygen consumption rates and ATP production. These mitochondrial defects coincided with a decrease in autophagy and mitophagy, indicated by reduced levels of autophagy- and mitophagy-associated proteins (i.e. ATGs, LC3A/B II, and BNIP3). Moreover, we found that TRPM2 modulates autophagy through a c-Jun N-terminal kinase (JNK)-dependent and mechanistic target of rapamycin-independent pathway. We conclude that in the absence of TRPM2, down-regulation of the JNK-signaling pathway impairs autophagy, ultimately causing the accumulation of damaged mitochondria and death of gastric cancer cells. Of note, by inhibiting cell proliferation and promoting apoptosis, the TRPM2 down-regulation enhanced the efficacy of paclitaxel and doxorubicin in gastric cancer cells. Collectively, we provide compelling evidence that TRPM2 inhibition may benefit therapeutic approaches for managing gastric cancer.

Functional Genomics Approach Identifies Novel Signaling Regulators of TGFα Ectodomain Shedding

Ectodomain shedding of cell-surface precursor proteins by metalloproteases generates important cellular signaling molecules. Of importance for disease is the release of ligands that activate the EGFR, such as TGFα, which is mostly carried out by ADAM17 [a member of the A-disintegrin and metalloprotease (ADAM) domain family]. EGFR ligand shedding has been linked to many diseases, in particular cancer development, growth and metastasis, as well as resistance to cancer therapeutics. Excessive EGFR ligand release can outcompete therapeutic EGFR inhibition or the inhibition of other growth factor pathways by providing bypass signaling via EGFR activation. Drugging metalloproteases directly have failed clinically because it indiscriminately affected shedding of numerous substrates. It is therefore essential to identify regulators for EGFR ligand cleavage. Here, integration of a functional shRNA genomic screen, computational network analysis, and dedicated validation tests succeeded in identifying several key signaling pathways as novel regulators of TGFα shedding in cancer cells. Most notably, a cluster of genes with NFκB pathway regulatory functions was found to strongly influence TGFα release, albeit independent of their NFκB regulatory functions. Inflammatory regulators thus also govern cancer cell growth-promoting ectodomain cleavage, lending mechanistic understanding to the well-known connection between inflammation and cancer.Implications: Using genomic screens and network analysis, this study defines targets that regulate ectodomain shedding and suggests new treatment opportunities for EGFR-driven cancers. Mol Cancer Res; 16(1); 147-61. ©2017 AACR.

Evolving role of FDG-PET/CT in prognostic evaluation of resectable gastric cancer

Gastric cancer (GC) remains a leading cause of cancer death worldwide. Radical gastrectomy is the only potentially curative treatment, and perioperative adjuvant therapies may improve the prognosis after curative resection. Prognosis largely depends on the tumour stage and histology, but the host systemic inflammatory response (SIR) to GC may contribute as well, as has been determined for other malignancies. In GC patients, the potential utility of positron emission tomography/computed tomography (PET/CT) with the imaging radiopharmaceutical ¹⁸F-fluorodeoxyglucose (FDG) is still debated, due to its lower sensitivity in diagnosing and staging GC compared to other imaging modalities. There is, however, growing evidence that FDG uptake in the primary tumour and regional lymph nodes may be efficient for predicting prognosis of resected patients and for monitoring tumour response to perioperative treatments, having prognostic value in that it can change therapeutic strategies. Moreover, FDG uptake in bone marrow seems to be significantly associated with SIR to GC and to represent an efficient prognostic factor after curative surgery. In conclusion, PET/CT technology is efficient in GC patients, since it is useful to integrate other imaging modalities in staging tumours and may have prognostic value that can change therapeutic strategies. With ongoing improvements, PET/CT imaging may gain further importance in the management of GC patients.

Clinical efficacy of endostar combined with chemotherapy in the treatment of peritoneal carcinomatosis in gastric cancer: results from a retrospective study

Peritoneal carcinomatosis (PC) resulting from metastatic dissemination of gastric cancer (GC) cells carries a dismal prognosis, and current treatments have shown little efficacy. This study aimed to evaluate the efficacy and safety of recombinant human endostatin (Endostar), a broad-spectrum anti-angiogenic peptide, in combination with chemotherapy in PC derived from GC. From January 2014 to December 2016, 33 patients with advanced stage GC associated with PC were enrolled. Pathological, imaging, and treatment data were retrospectively analyzed. Twenty-one patients received systemic chemotherapy (control group), while 12 patients were administered Endostar and chemotherapy. Combined treatment with Endostar/chemotherapy showed the tendency to increase objective response rate (41.7% vs. 23.8%) and disease control rate (83.3% vs. 61.9%) compared with the control group, although the differences were not statistically significant. Endostar plus chemotherapy effectively extended time to progression (4.6 ± 0.3 months vs. 3.5 ± 0.3 months, P = 0.03) and median overall survival (15.8 ± 1.7 months vs. 9.8 ± 0.9 months, P = 0.01) compared with chemotherapy alone. The combination therapy did not cause more adverse reactions than chemotherapy alone. Thus, the addition of Endostar to conventional chemotherapy treatment effectively attenuated the development of PC and extended survival, with high safety and tolerance.

MiR-129-5p influences the progression of gastric cancer cells through interacting with SPOCK1

The purpose of our study is to clarify the effect of microRNA-129-5p in the progression of human gastric cancer cells by regulating SPOCK1. The expression of microRNA-129-5p and SPOCK1 was tested by quantitative real-time polymerase chain reaction in tissues and cell lines. We validated the targeted relationship between microRNA-129-5p and SPOCK1 by dual luciferase reporter gene assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony formation, flow cytometry, transwell, and wound scratch assays were used to analyze the effects of microRNA-129-5p on SGC-7901 cell viability, proliferation, cell cycle and apoptosis, invasiveness, and migration. MicroRNA-129-5p was downregulated while SPOCK1 was upregulated in gastric cancer tissues and cell lines. The result of luciferase reporter gene assay demonstrated that microRNA-129-5p can target SPOCK1 by binding to the 3'untranslated region. The overexpression of microRNA-129-5p or the inhibition of SPOCK1 inhibited SGC-7901 viability, proliferation, migration, and invasion while promoted cell cycle arrest in G0/G1 stage and cell apoptosis. Our results suggested that microRNA-129-5p could directly specifically suppress SPOCK1, which might be one of the potential mechanisms in inhibiting cell processes including viability, proliferation, cell mitosis, migration, and invasiveness of gastric cancer cells.

Decreased expression of STING predicts poor prognosis in patients with gastric cancer

STING (stimulator of interferon genes) has recently been found to play an important role in host defenses against virus and intracellular bacteria via the regulation of type-I IFN signaling and innate immunity. Chronic infection with Helicobacter pylori is identified as the strongest risk factor for gastric cancer. Thus, we aim to explore the function of STING signaling in the development of gastric cancer. Immunohistochemistry was used to detect STING expression in 217 gastric cancer patients who underwent surgical resection. STING protein expression was remarkably decreased in tumor tissues compared to non-tumor tissues, and low STING staining intensity was positively correlated with tumor size, tumor invasion depth, lymph mode metastasis, TNM stage, and reduced patients’ survival. Multivariate analysis identified STING as an independent prognostic factor, which could improve the predictive accuracy for overall survival when incorporated into TNM staging system. In vitro studies revealed that knock-down of STING promoted colony formation, viability, migration and invasion of gastric cancer cells, and also led to a defect in cytosolic DNA sensing. Besides, chronic H. pylori infection up-regulated STING expression and activated STING signaling in mice. In conclusion, STING was proposed as a novel independent prognostic factor and potential immunotherapeutic target for gastric cancer.

Resection of Large Metachronous Liver Metastasis with Gastric Origin: Case Report and Review of the Literature

INTRODUCTION

Increasing evidence suggests that surgical resection may be offered to a subgroup of patients with liver metastasis of gastric adenocarcinoma. The aim of this case report is to illustrate the surgical resection of a single liver metachronous recurrence twelve months after a radical total gastrectomy for cancer.

CASE REPORT

A 63-year-old male patient with an Eastern Cooperative Oncology Group performance status of 1 was referred to our hospital for a single, large liver metastasis, twelve months after a radical total gastrectomy and DII lymphadenectomy for upper third gastric adenocarcinoma. As the adjuvant treatment, the patient received 12 cycles of FOLFOX chemotherapy. During the present admission, the abdominal computed tomography (CT) revealed a single liver metastasis located in the segments 5 and 6, of 105/85 mm in diameter. Surgical resection by an open approach of liver metastasis was decided. We performed a non-anatomical liver resection, without inflow control due to significant peritoneal adhesions in the liver hilum secondary to the previous lymphadenectomy. The patient was discharged after seven days, with an uneventful recovery. Six months after the second surgical procedure, the patient developed a local liver recurrence. The surgical resection of the liver recurrence was performed, with no postoperative morbidities, and the patient was discharged after eight days. Three months after the latest surgery, the patient is under adjuvant chemotherapy, with no imagistic signs of further recurrences.

CONCLUSIONS

  Hepatic resection for liver metastasis of gastric origin may offer satisfactory oncological outcomes in a very selected subgroup of patients.

Role of B7-H1 in gastrointestinal cancer

Immune evasion is a hallmark of cancer. Although cancer cells have been shown to be able to be recognized by T cells, host immune system fails to develop effective antitumor activity and tumor control. B7-H1, an immune inhibitory molecule, plays an important role in the immune evasion process. B7-H1 inhibits T cell immunity during immune priming and effector phases and is also implicated in intrinsic proliferation, apoptosis and migration of tumor cells. Targeting B7-H1 using blockade antibodies has generated immense antitumor activity in preclinical tumor models. Durable response for a variety of tumor types was also documented in clinical trials. Thus, B7-H1 targeted immune therapy offers a new line of tumor treatment. Gastrointestinal cancer is one of the leading causes of tumor morbidity. However, traditional therapy has not been able to effectively improve survival. This review will focus on the role of B7-H1 in immune evasion and the latest progression of the B7-H1 blockade immune therapy in gastrointestinal cancer.

Impact of a Eukaryotic Translation Initiation Factor 3a Polymorphism on Susceptibility to Gastric Cancer

OBJECTIVE

To investigate single nucleotide polymorphisms in the eukaryotic translation initiation factor 3a (eIF3a) gene and the risk for gastric cancer within the Chinese population.

SUBJECTS AND METHODS

A total of 322 patients with gastric cancer were selected as the patient group and 340 non-gastric cancer patients were selected as the control group using the case-control method. Polymerase chain reaction-sequence-specific primer technology was leveraged to genotype the rs77382849 single nucleotide polymorphism in the eIF3a gene. The demographic characteristics of the study population and other exposures to risk factors were collected. Unconditional logistic regression analysis was performed to determine the association between the risk factors and gastric cancer.

RESULTS

A higher frequency of the eIF3a rs77382849 GG homozygote genotype was observed in the gastric cancer patients compared with the controls (63.98 vs. 54.41%, p < 0.05). After adjustment of exposure risks, such as age, gender, smoking, and drinking, the rs77382849 single nucleotide polymorphism was still associated with susceptibility to gastric cancer. When the eIF3a rs77382849 GG homozygote genotype was used as the reference group, the GA genotype (GA vs. GG: OR = 0.545, 95% CI: 0.386-0.769, p = 0.001) and AA genotype (AA vs. GG: OR = 0.245, 95% CI: 0.072-0.836, p = 0.025) were both correlated with a significantly decreased risk for gastric cancer development.

CONCLUSION

An association between eIF3a rs77382849 polymorphism and susceptibility to gastric cancer was observed in these Chinese patients.