Human Gastric Cancer Patients Research Articles

Up-regulation of Aquaporin 5 Defines Spasmolytic Polypeptide-Expressing Metaplasia and Progression to Incomplete Intestinal Metaplasia.

Background & AimsMetaplasia in the stomach is highly associated with development of intestinal-type gastric cancer. Two types of metaplasias, spasmolytic polypeptide-expressing metaplasia (SPEM) and intestinal metaplasia (IM), are considered precancerous lesions. However, it remains unclear how SPEM and IM are related. Here we investigated a new lineage-specific marker for SPEM cells, aquaporin 5 (AQP5), to assist in the identification of these 2 metaplasias.MethodsDrug- or Helicobacter felis (H felis) infection-induced mouse models were used to identify the expression pattern of AQP5 in acute or chronic SPEM. Gene-manipulated mice treated with or without drug were used to investigate how AQP5 expression is regulated in metaplastic lesions. Metaplastic samples from transgenic mice and human gastric cancer patients were evaluated for AQP5 expression. Immunostaining with lineage-specific markers was used to differentiate metaplastic gland characteristics.ResultsOur results revealed that AQP5 is a novel lineage-specific marker for SPEM cells that are localized at the base of metaplastic glands initially and expand to dominate glands after chronic H felis infection. In addition, AQP5 expression was up-regulated early in chief cell reprogramming and was promoted by interleukin 13. In humans, metaplastic corpus showed highly branched structures with AQP5-positive SPEM. Human SPEM cells strongly expressing AQP5 were present at the bases of incomplete IM glands marked by TROP2 but were absent from complete IM glands.ConclusionsAQP5-expressing SPEM cells are present in pyloric metaplasia and TROP2-positive incomplete IM and may be an important component of metaplasia that can predict a higher risk for gastric cancer development.

The role of TRPV1 ion channels in the suppression of gastric cancer development

BackgroundAlthough the aberrant expression and function of most Ca2+-permeable channels are known to promote gastrointestinal tumors, the association between transient receptor potential vanilloid receptor 1 (TRPV1) channels and gastric cancer (GC) has not yet been explored. Herein, we sought to determine the role of TRPV1 channels in the development of GC and to elucidate the underlying molecular mechanisms involved therein.MethodsImmunohistochemistry, qPCR, Western blot, immunofluorescence assays were used to detect the mRNA and protein expression of TRPV1 in GC cells and tissues, and the clinical significance of TRPV1 in GC was also studied by clinicopathologic analysis. CCK8, colony formation, flow cytometry assays were used to detect the proliferation and survival of GC cells, while transwell assay was used to detect migration and invasion of GC cells in vitro. Tumor xenograft and peritoneal dissemination assays in nude mice were used to examine the role of TRPV1 in GC development in vivo.ResultsTRPV1 expression was significantly downregulated in human primary GC tissues compared to their adjacent tissues. The decreased expression of TRPV1 proteins in GC tissues was positively correlated with tumor size, histological grade, lymphatic metastasis, clinical stage, and was strongly correlated with poor prognosis of GC patients. Moreover, the expression of TRPV1 was closely correlated with Ki67, VEGFR, and E-cadherin, all of which are the well-known cancer markers for proliferation and metastasis. TRPV1 proteins were predominately expressed on the plasma membrane in several GC cell lines. TRPV1 overexpression blocked cell cycle at G1 phase to inhibit GC cell proliferation and attenuated migration and invasion of GC cells in vitro, but TRPV1 knockdown increased these parameters. TRPV1 significantly reduced gastric tumor size, number and peritoneal dissemination in vivo. Mechanistically, TRPV1 overexpression in GC cells increased [Ca2+]i, activated CaMKKβ and AMPK phosphorylation, and decreased expression of cyclin D1 and MMP2, while TRPV1 knockdown induced the opposite effects.ConclusionsTRPV1 uniquely suppresses GC development through a novel Ca2+/CaMKKβ/AMPK pathway and its downregulation is correlated with poor survival of human GC patients. Thus, TRPV1 upregulation and its downstream signaling may represent a promising target for GC prevention and therapy.

Lipid accumulation in macrophages confers protumorigenic polarization and immunity in gastric cancer.

Heterotypic interactions between tumor cells and macrophages can enable tumor progression and hold potential for the development of therapeutic interventions. However, the communication between tumors and macrophages and its mechanism are poorly understood. Here, we find that tumor‐associated macrophages (TAM) from tumor‐bearing mice have high amounts of lipid as compared to macrophages from tumor‐free mice. TAM also present high lipid content in clinical human gastric cancer patients. Functionally, TAM with high lipid levels are characterized by polarized M2‐like profiling, and exhibit decreased phagocytic potency and upregulated programmed death ligand 1 (PD‐L1) expression, blocking anti–tumor T cell responses to support their immunosuppressive function. Mechanistically, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identifies the specific PI3K pathway enriched within lipid‐laid TAM. Lipid accumulation in TAM is mainly caused by increased uptake of extracellular lipids from tumor cells, which leads to the upregulated expression of gamma isoform of phosphoinositide 3‐kinase (PI3K‐γ) polarizing TAM to M2‐like profiling. Correspondingly, a preclinical gastric cancer model is used to show pharmacological targeting of PI3K‐γ in high‐lipid TAM with a selective inhibitor, IPI549. IPI549 restores the functional activity of macrophages and substantially enhances the phagocytosis activity and promotes cytotoxic‐T‐cell‐mediated tumor regression. Collectively, this symbiotic tumor‐macrophage interplay provides a potential therapeutic target for gastric cancer patients through targeting PI3K‐γ in lipid‐laden TAM.

The Role of YAP Oncogene in Metastasis and Mechano‐medicine

YAP is a WW domain‐containing protein that acts as a potent oncogene and stemness factor. It is one of the two main effectors of the Hippo tumor suppressor pathway. YAP is a transforming gene of the chromosome 11q22 amplicon, and its expression is elevated at high frequency in human cancers, including liver, breast, ovarian and stomach cancer. Our recent work showed that YAP regulates the acto‐myosin network by suppressing Rho‐GTPase via Rho‐GTPase activating protein 29 (ARHGAP29) being a direct transcriptional target of YAP in human gastric cancer. We showed that YAP promoted the expression of ARHGAP29 to suppress the RhoA‐LIMK‐cofilin pathway, thereby destabilizing F‐actin. The overexpression of YAP caused cytoskeletal rearrangement by altering the dynamics of F‐actin/G‐actin turnover, thus promoting migration. In a mouse model, circulating tumor cells (CTCs) exhibited an increase in ARHGAP29 RNA level compared with cells at primary tumor sites. Moreover, increased ARHGAP29 expression correlated with shortened survival of human gastric cancer patients. Importantly, we showed that ARHGAP29 is critical in regulating cancer metastasis in a mouse model of liver cancer metastasizing to lungs.We have also identified YAP and TAZ specific transcripts and we are characterizing them now as mechano‐responsive transcripts that regulate cell metastasis and mechano‐sensing.Cancer cells are generally softer than normal cells. By increasing the rigidity of cancer cells to the level of normal cells via novel therapeutic interventions, and by reducing rigidity of extracellular matrix of tumors we could provide a new modality to treat cancer in unison with other standard therapies.Support or Funding InformationStart‐Up Funds from National University of Singapore (R‐185‐000‐2710‐733) and Mechanobiology Institute (R‐714‐018‐006‐271)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Abstract B191: The impact of postoperative myeloid-derived suppressor cells on prognosis of gastric cancer patients

Abstract Background and Aim: Myeloid cells such as myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs) and neutrophils have a suppressive role in the antitumor immunity. In gastric cancer (GC) patients, it has been reported that these myeloid cells in peripheral blood or tumor tissue were associated with their prognosis and increased after surgical treatments. Some reported that the tumor progression and frequent recurrence were caused by increased MDSC after surgical stress in a mouse model. However, in human GC patients, it is still unclear whether such an increase of myeloid cells after gastrectomy is related to their poor prognosis. In this study, we investigate the relationship between the increase of myeloid cells after surgery and prognosis in gastric cancer patients. Materials and Methods: For analysis of relationship between increased myeloid cells after surgery and patients’ prognosis, general archival data were obtained from 278 pStgae2-3 GC patients who received curative resection between January 2007 and December 2014. For analysis of relationship between perioperative changes of MDSCs and patients’ clinicopathologic data, peripheral blood was obtained from 75 GC patients who underwent gastrectomy between April 2016 and December 2017, and MDSCs, CD8, CD4 T-cells, and regulatory T-cells (Tregs) were analyzed by flow cytometry. For analysis of the immunosuppressive function, MDSCs were purified by FACS Aria II and the IFNγ secretion assay were performed using activated autologous T-cells as responder cells. Result and Discussion: In the analysis with 278 GC patients, short RFS was significantly correlated with increased number of monocytes after surgery (#monocytes) (P=0.0073), but not increased number of neutrophils (#neutrophils) (P=0.26). A multivariate analysis demonstrated that #monocytes (HR 1.49; 95% CI 1.01-2.21), pT (HR 2.14; 95% CI 1.26-3.83), pN (HR 2.98; 95% CI 1.81-5.18), postoperative complications (HR 1.69; 95% CI 1.03-2.68) were independently associated with RFS. In the analysis with 75 GC patients, preoperative % M-MDSCs (CD11b+ CD33+ HLA-DR- in CD14+ PBMCs) was positively associated with pathologic stages. After gastrectomy, % M-MDSCs dramatically increased in most patients. On the other hand, % Foxp3+ CD25+ in CD4+ increased but not significantly, while % CD4 and %CD8 in CD3+ were stable. By the suppression assay, smaller number of IFNγ-secreting responder cells were observed when they were co-cultured with M-MDSCs than with CD11b+ CD33+HLA-DR+ cells. Because the increase in the number of M-MDSCs (#M-MDSCs) was positively correlated with #monocytes (r2=0.57 P<0.0001), #M-MDSCs after surgery might be related to poor prognosis of GC patients. Conclusion: The larger number of monocytes after gastrectomy was independently associated with poorer prognosis. The immunosuppressive effect of M-MDSCs increased after surgery could be one of the reasons for the early relapse in gastric cancer patients. Citation Format: Shinya Urakawa, Hisashi Wada, Masaki Mori, Yuichiro Doki. The impact of postoperative myeloid-derived suppressor cells on prognosis of gastric cancer patients [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B191.

Abstract 1259: Loss of TFF1 promotes growth and chemotherapeutic resistance in gastric cancer

Abstract Background: Downregulation or loss of TFF1 expression occurs in more than half of human gastric adenocarcinomas through gene deletions, mutation, and a loss of heterozygosity or hypermethylation. Our previous studies have shown that Tff1 knockout (KO) in mice induces gastric lesions from low- grade dysplasia (LGD), high- grade dysplasia (HGD) to adenocarcinoma. BRD2, a family member of BET proteins, promotes aberrant gene expression in a variety of malignant tumors. In this study, with the analysis of Tff1 KO mice and human gastric cancer tissue samples, we discovered that loss of Tff1 promotes gastric cancer proliferation and drug resistance through upregulating BRD2 expression level. Methods and Results: Integration Next Generation Sequencing data analysis in both Tff1 KO mice and human gastric cancer tissue samples demonstrated that miR-143-3p was significantly down-regulated in both mice and human gastric cancer samples (P<0.05). Our findings were further validated by RT-PCR in Tff1 KO mouse gastric legions (LGD and adenocarcinoma) and 3 different cohorts of human gastric cancer tissue samples from USA, Chile, and China. Using different gastric cancer cell models we further confirmed the decrease of miR-143-3p regulated by loss of TFF1. Next, we wanted to find out the downstream effector of miR-143-3p down-regulation. Western blot data showed that BRD2 protein level was regulated by miR-143-3p in 4 gastric cancer cell lines. BRD2 3'UTR luciferase reporter assay further confirmed that miR-143-3p decreased BRD2 protein expression through directly binding to its 3'UTR sites. These data suggested that, for the first time, BRD2 is a direct downstream target of miR-143-3p. At the meantime, the reconstitution of TFF1 in gastric cancer cells up-regulated miR-143-3p expression level, which in turn, decreased the protein expression levels of BRD2, MYC and BCL-2. Using western blot, we showed the synergistic effect of BRD2 inhibitor and CDDP chemotherapy in human gastric cancer cells. Data from 320 human gastric cancer patients demonstrated that high BRD2 expression level in gastric cancer tissues significantly decreased the overall patient survival rate (P<0.0001). Conclusion: This study unveils, for the first time, loss of TFF1 promotes BRD2 activation in gastric cancer through decreasing miR-143-3p. This axis presents novel therapeutic opportunities by using approaches that reconstitute miR-143-3p or utilizing the recently developed clinical trials in human gastric cancer. Citation Format: Zheng Chen, Zheng Li, Mohammed Soutto, Weizhi Wang, Shoumin Zhu, Alejandro Corvalan, Zekuan Xu, Wael El-Rifai. Loss of TFF1 promotes growth and chemotherapeutic resistance in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1259.

Stemness Is Enhanced in Gastric Cancer by a SET/PP2A/E2F1 Axis.

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer-related deaths worldwide. Chemotherapies against gastric cancer often fail, with cancer recurrence due potentially to the persistence of cancer stem cells. This unique subpopulation of cells in tumors possesses the ability to self-renew and dedifferentiate. These cancer stem cells are critical for initiation, maintenance, metastasis, and relapse of cancers; however, the molecular mechanisms supporting cancer stemness remain largely unknown. Increased kinase and decreased phosphatase activity are hallmarks of oncogenic signaling. Protein phosphatase 2A (PP2A) functions as a tumor-suppressor enzyme, and elevated levels of SET/I2PP2A, an endogenous PP2A protein inhibitor, are correlated with poor prognosis of several human cancers. Here, it was determined that SET expression was elevated in tumor tissue in a gastric cancer mouse model system, and SET expression was positively correlated with poor survival of human gastric cancer patients. Mechanistically, SET knockdown decreased E2F1 levels and suppressed the stemness of cancer cell lines. Immunoprecipitations show SET associated with the PP2A-B56 complex, and the B56 subunit interacted with the E2F1 transcription factor. Treatment of gastric cancer cells with the SET-targeting drug OP449 increased PP2A activity, decreased E2F1 protein levels, and suppressed stemness of cancer cells. These data indicate that a SET/PP2A/E2F1 axis regulates cancer cell stemness and is a potential target for gastric cancer therapy.Implications: This study highlights the oncogenic role of SET/I2PP2A in gastric cancer and suggests that SET maintains cancer cell stemness by suppressing PP2A activity and stabilizing E2F1. Mol Cancer Res; 16(3); 554-63. ©2018 AACR.

YAP Regulates Actin Dynamics through ARHGAP29 and Promotes Metastasis

Yes-associated protein (YAP) is regulated by mechanical cues via the interaction of the Hippo pathwaywith cytoskeleton. Previous studies showed that YAPplays a role in regulating the actomyosin network by suppressing Rho GTPase in medaka fish. Here, weidentify Rho GTPase activating protein29 (ARHGAP29) as a transcriptional target of YAP in ahuman gastric cancer cell line. YAP promotesthe expression of ARHGAP29 to suppress the RhoA-LIMK-cofilin pathway, destabilizing F-actin. The overexpression of YAP causes cytoskeletal rearrangement by altering the dynamics of F-actin/G-actin turnover, thus promoting migration. In a mouse model, circulating tumor cells (CTCs) exhibit an increased ARHGAP29 RNA level compared with cells at primary tumor sites, and the metastatic potential of CTCs is positively correlated with ARHGAP29 expression. Moreover, increased ARHGAP29 expression is correlated with shortened survival of human gastric cancer patients. Our study provides a model to understand YAP's contribution to cancer metastasis via regulation of actin dynamics.

Higher Numbers of T-Bet+ Tumor-Infiltrating Lymphocytes Associate with Better Survival in Human Epithelial Ovarian Cancer

Background/Aims: T-bet, a member of the T-box family of transcription factors, is a key marker of type I immune response within the tumor microenvironment, and has been previously reported by us to serve as an important prognostic indicator for human gastric cancer patients and a potential biomarker for immunotherapy. In the present study, we aimed to assess the clinical significance and prognostic value of T-bet⁺ tumor-infiltrating lymphocytes in human epithelial ovarian cancer. Methods: The immunohistochemistry was used to analyze the infiltration density of T-bet⁺ lymphoid cells in human epithelial ovarian cancer tissues, and the flow cytometry analysis was used to further analyze the presence of T-bet⁺ tumor-infiltrating lymphocytes subgroups in cancer tissues. Results: Our immunohistochemistry analysis showed increased number of T-bet⁺ lymphoid cells in the human epithelial ovarian cancer tissues, and the flow cytometry analysis further demonstrated the presence of T-bet⁺ tumor-infiltrating lymphocytes subgroups including CD4⁺ , CD8⁺ T cells and NK cells. In addition, we also observed a significant association of T-bet⁺ tumor-infiltrating lymphocytes density in the tumor nest of cancer with not only serum CA125 levels but also with distant metastasis. However no association was observed with other characteristics like patients' age, pathological type, FIGO stage, tumor site and tumor size. Furthermore, the survival analysis showed that higher density of T-bet⁺ tumor-infiltrating lymphocytes both in tumor nest and tumor stroma of cancer tissues was significantly associated with better patient survival. In addition, the density of T-bet⁺ tumor-infiltrating lymphocytes in tumor nest appeared to be an independent risk factor for predicting patients’ postoperative prognoses. Conclusions: Our data indicated that the key transcription factor T-bet might play an important role in the type I immune cells mediated antitumor response, and the density of T-bet⁺ lymphocytes in human epithelial ovarian cancer tissues could serve as a prognostic predictor for ovarian cancer patients.

Abstract 3813: Potent compounds targeting the human MutT homolog 1 (hMTH1) activity and their cytotoxicity evaluation

Abstract Recently, it has been reported that MTH1, a sanitizing protein for the oxidized dNTP pool, plays an important role in cancer-associated damage in the dNTP pool and is required for survival in cancer cells. To study the antitumor mechanism of MTH1 and screen effective anti-cancer drugs, the current study was designed to set up an in vitro expressing and activity evaluation system for MTH1, which will be used for MTH1 specific inhibitor screening. Briefly, the acquired recombinant vector pET-28b-MTH1 was transfected into E.Coli BL21(DE3). The MTH1 protein expression was induced by IPTG and purified by Ni2+ affinity chromatography. Through converting dGTP to dGMP and pyrophosphate by MTH1, the latter of which can then be hydrolyzed to inorganic pyrophosphate by inorganic pyrophosphatase, the MTH1 activity is evaluated through measuring the amount of inorganic pyrophosphate after reacting with malachite green and ammonium molybdate at 630nm. Using this method, we have successfully generated a reliable in vitro evaluation system for MTH1 activity. Furthermore, five brand new series of hybrids with total more than one hundred compounds were virtually designed and synthesized. Their potential MTH1 inhibitory effects were screened based on our system. We found that some of them exhibited moderate to excellent inhibitory activity toward MTH1 with nanomole IC50 values, which also showed significant cytotoxicity on several gastric cancer cell lines by MTT assay (with IC50 below 10μM). On the other hand, our studies in human gastric cancer patients also indicated that MTH1 expression levels were significantly enhanced in these patients’ cancer tissues, compared to the para-cancer ones. Our findings suggest that MTH1 may be a potential therapeutic target in gastric cancer. Compounds specifically designed to target MTH1 activity may represent a novel and useful strategy for anti-gastric cancer drug discovery. *Corresponding author: Wen Zhao, Ph.D, Tel.: 01186-15003898187. Email: zhaowen100@139.com Funding Sources. This work was supported by National Natural Science Foundation of China (Project No. 81430085, No. 21372206 and No. 81172937 for H.-M.L.; Project No. 81270270 and No. 81470524 for W.Z.); Ph.D Educational Award from Ministry of Education (No. 20134101130001, for H.-M.L. and No. 20134101110013, for W.Z.); The 2013 Scientific Innovation Talent Award from Department of Education of Henan Province (No. 13HASTIT029, for W.Z.). Citation Format: Wenjuan Zhou, Liying Ma, Biao Hu, Lingyu Li, Bo Wang, Hong-Min Liu, Wen Zhao. Potent compounds targeting the human MutT homolog 1 (hMTH1) activity and their cytotoxicity evaluation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3813.

Abstract 1443: IL-18 is associated with the onset and progression of gastric cancer

Abstract INTRODUCTION: Gastric cancer (GC) is the fourth most prevalent, and the third most common cause of cancer-related death worldwide. The disease is generally asymptomatic, and consequently is often diagnosed at an advanced stage when metastasis is present, and limited treatment options are available. Chronic inflammation is recognized as an integral component in the development and progression of GC, and is associated with increased infiltration of immune cells into the tumor microenvironment. The production of pro-inflammatory cytokines by these cells may contribute to tumor progression through activation of pathways promoting tumor cell survival and proliferation. Previous work from our lab has shown that therapeutic inhibition of the inflammatory cytokine interleukin (IL)-11 is effective in ameliorating disease progression in gastrointestinal cancer, however, it is unclear what role other pro-inflammatory cytokines, such as IL-18, might have in disease progression. METHODS: To characterize the role of different pro-inflammatory cytokines in GC, we first analyzed microarray and qRT-PCR data of from human GC specimens and adjacent non-tumor tissue. Following the generation of a candidate list of cytokines deregulated in human GC, the role of individual cytokines in disease progression was examined using a validated mouse model of intestinal-type GC, referred to as gp130Y757F, by crossing into cytokine knock-out strains and monitoring tumor burden and the expression of genes and proteins classically associated with tumorigenesis. RESULTS: We found that the expression pro-inflammatory cytokines including IL-1β and IL-18 were significantly elevated in the tumors of human GC patients compared to non-tumor tissue. In gp130Y757F mice, genetic ablation of IL-18, but not of IL-1β significantly reduced gastric tumor burden, which was associated with a reduction in the number of intratumoral macrophages, but not lymphocytes. This observation correlated with decreased expression of pro-inflammatory (Ifng, Tgfb1), antimicrobial (Reg3b, Reg3g), and tissue remodeling (Mmp9) genes, and a reduction in apoptosis in the gastric lesions in these mice. CONCLUSION: Our results demonstrate that IL-18 has an important role in GC disease progression, and may serve as a potential therapeutic target. Citation Format: Paul Nguyen, Rita Busuttil, Lisa Mielke, Gabrielle Belz, Alex Boussioutas, Matthias Ernst, Tracy Putoczki. IL-18 is associated with the onset and progression of gastric cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1443.

High Infiltration of Tumor-Associated Macrophages Influences Poor Prognosis in Human Gastric Cancer Patients, Associates With the Phenomenon of EMT.

Tumor-associated macrophages (TAMs) are associated with poor prognosis in numerous human cancers and play important roles in tumor progression. Epithelial-mesenchymal transition (EMT) contributes to invasion and metastasis in cancer. However, the associations between TAMs and EMT are not clear in gastric cancer (GC). The present study was designed to investigate the effects of TAMs on EMT in human GC.TAMs marker CD68 and EMT-related proteins were detected by immunohistochemistry (IHC) in human GC tissues and their clinical significance were evaluated.A high level of infiltration of TAMs was associated with aggressive characteristics of tumor and an independent poor prognostic factor in human GC tissues. Infiltration of TAMs was also associated with EMT-related proteins in human GC tissues.Our findings suggest that the high level of infiltration TAMs was associated with aggressive features of GC and is an independent poor prognostic factor in GC patients. TAMs are associated with EMT induction in human GC tissues. The level of TAMs infiltration may be used as a prognostic factor and even a therapeutic target in GC.

The effect of ω-fatty acids on the expression of phospholipase A2 group 2A in human gastric cancer patients.

Background:Studies show that polyunsaturated fatty acids (PUFAs) may have an inhibitory role in carcinogenesis. It was previously shown that PLA2 group 2A (PLA2G2A) messenger RNA (mRNA) expression is associated with less frequent metastasis and longer survival in gastric adenocarcinoma. This study intends to investigate the effect of PUFAs on the expression of PLA2G2A in patients with gastric cancer.Materials and Methods:Thirty-four patients with gastric cancer (GC) were randomly divided into two groups. The first group received cisplatin medication. The second group received cisplatin medication and supplements of ω-fatty acids for three courses. The total RNA was extracted from the tissues and cDNA was synthesized. The gene expression of PLA2G2A was evaluated by the real-time polymerase chain reaction (PCR) method. To confirm the changes in gene expression, frozen section was utilized. The frozen tissue samples were sectioned and stained using the immunohistochemistry technique.Results:After chemotherapy and chemotherapy plus supplement, the relative mean of PLA2G2A gene expression increased 1.5 ± 0.5-fold and 7.4 ± 2.6-fold, respectively (P = 0.006). The relative mean of gene expression in patients who received cisplatin and ω-fatty acids supplement increased more significantly (7.5 ± 3.3-fold) than in patients who received only cisplatin (P = 0.016).Conclusion:It was found that PUFAs increased the gene and protein expression of PLA2G2A in gastric cancer. Concerning the fact that studies reveal protective function of PLA2G2A in gastric cancer, it is suggested that increased expression of PLA2G2A is helpful. Furthermore, PUFAs can be considered as a useful therapeutic supplement for patients with gastric cancer.

Activated Pak4 expression correlates with poor prognosis in human gastric cancer patients

Despite considerable advances in gastrectomy and chemotherapy, the prognosis of gastric cancer (GC) has not noticeably improved due to lymph node or distant metastases. P21-activated serine/threonine kinase 4 (Pak4) plays an important role in cell morphology and cytoskeletal reorganization-both prerequisite steps for cell migration. However, it is still unclear if activated Pak4 (p-Pak4) is related to prognosis in GC patients. In our study, the level of p-Pak4 in 95 GC tissue specimens was examined by immunohistochemistry (IHC). We observed significant correlation between the level of p-Pak4 and grosstype (advanced stage GC vs. early stage GC, P = 0.04). Moreover, GC patients with higher p-Pak4 levels had a poorer prognosis than those with lower p-Pak4 levels (17 vs. 38 months, P = 0.001). Multivariate analysis showed that high phosphorylation level of Pak4, advanced stage GC, and lymph node metastasis were independent prognostic factors for GC patients (p-Pak4, P = 0.026; advanced stage GC, P = 0.030; lymph node metastasis, P = 0.016). In addition, in vitro assays indicated that knockdown of Pak4 accompanied with decreased p-Pak4, inhibited cell migration via downregulation of the traditional downstream signaling pathways of Pak4, LIMK1, and cofilin. In conclusion, this report reveals that high level of p-Pak4 correlates with poor prognosis in GC, thereby suggesting that p-Pak4 might be a potential prognostic marker for GC.

Isolation and characterization of circulating tumor cells from human gastric cancer patients.

Circulating tumor cells (CTCs) have been proved to be responsible for tumor metastasis and resistant to anticancer therapies. This study aims to isolate and characterize circulating tumor cells from human gastric cancer patients, and investigate characteristic differences between gastric CTCs and gastric cancer cell lines. We analyzed 31 cases of gastric cancer patients using anti-CD45 antibody-conjugated magnetic microbeads negative separation, combined with fluorescence activated cell sorter CD44 positive screening. Abilities of tumor formation, metastasis, invasion, migration, irradiation and drug sensitivity of CTCs and gastric cancer cell lines were detected and compared. Of all the 31 patients, CD44(+)/CD45(-)CTCs were isolated in 14 patients, of which 3 cases were stage IIA, 2 cases stage IIB, 2 cases stage IIIC and 7 cases stage IV. The malignant behavior was demonstrated by both clonogenetic assay and tumor xenograft in nude mice. Compared with human gastric cancer cell lines, the migration and invasion abilities of CTCs increased to 3.21-12.6-fold and 2.3-6.7-fold, respectively (all p values <0.05). In addition, the metastatic potential of CTCs is much higher in vivo than that of the control. Furthermore, CTCs were found to be relatively sensitive to FU, cisplatin and paclitaxel, but relatively resistant to irradiation, oxaliplatin, cetuximab and trastuzumab. CD44(+)/CD45(-) gastric CTCs were isolated and found to exhibit stronger malignant behavior when compared with human gastric cancer cell lines. Furthermore, CTCs cultured in vitro have potential implications in drug sensitivity screening for the future anticancer treatments.

Effect of Fibulin-5 on cell proliferation and invasion in human gastric cancer patients

ObjectivesTo explore the effect of Fibulin-5 expression on cell proliferation and invasion in human gastric cancer patients. MethodsFibulin-5 expression was detected in 56 samples of surgically resected gastric cancer and paired noncancerous tissues using qRT-PCR and immunoblotting. Fibulin-5 was knocked down by Fibulin-5 shRNA in MGC-803 cells, then BrdU cell proliferation and transwell invasion assays were used to determine cell proliferation and invasion. ResultsThe level of Fibulin-5 mRNA in gastric cancer tissues was significantly higher as compared with that in normal tumor-adjacent tissues (P<0.05). Otherwise, the level of Fibulin-5 protein in cancer and noncancerous tissues was consistent with mRNA expression (P<0.05). Fibulin-5 protein expression in tumor tissues with poorly differentiated, lymph node metastasis and advanced TNM tumor stage was significantly higher (P<0.05, respectively). Fibulin-5 was obviously knocked down by Fibulin-5 shRNA (P<0.05), and Fibulin-5 knockdown significantly inhibited cell proliferation and invasion in MGC-803 cells (P<0.05, respectively). ConclusionsThe high-expression of Fibulin-5 is associated with the malignant clinicopathologic parameters in gastric cancer and Fibulin-5 knockdown inhibits cell proliferation and invasion in MGC-803 cells, suggesting Fibulin-5 may act as a key factor in the progression of gastric cancer.

Expression of early growth response-1 in human gastric cancer and its relationship with tumor cell behaviors and prognosis

The early growth response-1 (Egr-1) is crucial in many cell regulatory processes related to the progression of human cancers. Its overexpression has been demonstrated in variable human cancers and may have prognostic significance. The aims of this current study were to evaluate whether Egr-1 affects invasive and oncogenic phenotypes of human gastric cancer cells, and to examine the relationships between its expression and various clinicopathological parameters, including survival in human gastric cancer patients.We investigated the biologic role of Egr-1 in tumor cell behavior by using a small interfering RNA in human gastric cancer cell lines, AGS and TMK1. The expression of Egr-1 by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry was investigated in human gastric cancer tissues.The knockdown of Egr-1 suppressed tumor cell migration and invasion in AGS and TMK1 cells. Egr-1 expression was significantly increased in human gastric cancer and metastatic lymph node tissues compared to the normal gastric mucosa and non-metastatic lymph node tissues. Positive expression of Egr-1 was significantly associated with tumor size, depth of invasion, lymph node metastasis, tumor stage and poor survival.These results indicate that Egr-1 is associated with human gastric cancer progression through the alteration of tumor cell behavior, such as migration and invasion. Egr-1 expression may help in predicting the clinical outcomes of human gastric cancer patients.

Preservation of peritoneal fibrinolysis owing to decreased transcription of plasminogen activator inhibitor-1 in peritoneal mesothelial cells suppresses postoperative adhesion formation in laparoscopic surgery

Postoperative adhesion formation is regulated by peritoneal fibrinolysis, which is determined by tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). This study compared peritoneal fibrinolysis and adhesion formation after laparoscopic surgery (LAP) and open surgery (OP). We divided 154 male rats into 3 groups after cecal cauterization: Control, no treatment; LAP, CO2 pneumoperitoneum at 5 mmHg for 60 minutes; and OP, laparotomy for 60 minutes. Adhesions were quantified at day 7. The activity and mRNA level of tPA and PAI-1 were determined by enzyme-linked immunosorbent assay in plasma and peritoneal lavage and by real-time polymerase chain reaction in peritoneal mesothelial cells from omentum. We also examined peritoneal fibrinolysis in human gastric cancer patients treated with LAP (n = 14) or OP (n = 10). In the animal study, adhesion scores, PAI-1 activity in peritoneal lavage fluid, and PAI-1 mRNA levels in peritoneal mesothelium were significantly greater in the OP group than the control and LAP groups. In the human study, postoperative PAI-1 mRNA levels were significantly greater in the OP group than the LAP group. Additionally, PAI-1 mRNA levels and subsequent adhesion formation were induced by prolonged operative time in the OP group, but not the LAP group. Preservation of peritoneal fibrinolysis owing to decreased PAI-1 expression at the transcriptional level in peritoneal mesothelial cells is associated with suppression of postoperative adhesion formation in LAP. PAI-1 mRNA levels and subsequent adhesion formation were not induced by prolonged operative time in LAP. These results highlight the less invasiveness nature of LAP.

CHIP functions as a novel suppressor of tumour angiogenesis with prognostic significance in human gastric cancer

ObjectiveCHIP (carboxy terminus of Hsc70 interacting protein) is an E3 ubiquitin ligase that can induce ubiquitination and degradation of several tumour related proteins, and acts as a suppressor of tumour...

Reg IV enhances peritoneal metastasis in gastric carcinomas

The role of Regenerating (Reg) IV on peritoneal metastasis was examined in gastric cancer using. Reg IV-transfected human gastric cancer cells (MKN28-R1, MKN28-R2, TMK1-R1), control transfectants (MKN28-R0, TMK1-R0), and REG4-knocked down MKN45 cells were examined in in vitro and in nude mice peritoneal metastasis models. Increase of expression and secretion of Reg IV, and levels of BCL-2, BCL-XL,survivin, phosphorylated AKT, and phosphorylated EGFR, and decrease of nitric oxide-induced apoptosis were found in Reg IV-transfectants, whereas those were abrogated in the knockdown cells. In mice models, increased number and size of peritoneal tumors and decreased apoptosis were found in Reg IV-transfectants, whereas those were abrogated by the knockdown cells. Mice survivals were worsened in Reg IV-transfectants-inoculated mice, but were improved in Reg IV-knockdown cell-inoculated mice. Levels of Reg IV protein in peritoneal lavage fluids increased in Reg IV-transfectants inoculated mice, but decreased in Reg IV-knockdown cell inoculated mice. In metastasized human gastric cancers, Reg IV positivity in peritoneum-metastasis cases was higher than those in negative cases. Reg IV was detected in peritoneal lavage fluids from human gastric cancer patients, in whose lavages keratin mRNA was detected by reverse transcriptase-polymerase chain reaction. Collectively, Reg IV might accelerate peritoneal metastasis in gastric cancer. Reg IV in lavage fluids might be a good marker for peritoneal metastasis.