Effects of altered glycolysis levels on CD8+ T cell activation and function.

CD8+ T cells are an important component of the body's adaptive immune response. During viral or intracellular bacterial infections, CD8+ T cells are rapidly activated and differentiated to exert their immune function by producing cytokines. Alterations in the glycolysis of CD8+ T cells have an important effect on their activation and function, while glycolysis is important for CD8+ T cell functional failure and recovery. This paper summarizes the importance of CD8+ T cell glycolysis in the immune system. We discuss the link between glycolysis and CD8+ T cell activation, differentiation, and proliferation, and the effect of altered glycolysis on CD8+ T cell function. In addition, potential molecular targets to enhance and restore the immune function of CD8+ T cells by affecting glycolysis and the link between glycolysis and CD8+ T cell senescence are summarized. This review provides new insights into the relationship between glycolysis and CD8+ T cell function, and proposes novel strategies for immunotherapy by targeting glycolysis.

[Corrigendum] CXCR1 promotes malignant behavior of gastric cancer cells in vitro and in vivo in AKT and ERK1/2 phosphorylation.

Subsequently to the publication of the above article, the authors contacted the Editorial Office to explain that they had inadvertently included data from the same original source in the first row of data panels in Fig. 4B on p. 2191 (showing the results of cell migration assay experiments) to represent two differently performed experiments. Specifically, these images (second and third data panels) containing partially overlapping data corresponded to the 'Vacant­BGC823' in the empty plasmid transfection group and the background 'BGC823 cell' groups, respectively. However, the authors had retained their original data, which they presented to the office for our inspection, and were able to reassemble the data correctly in the figure. The revised version of Fig. 4, showing the replacement data for the 'Vacant­BGC823' and 'BGC823' Migration panels in Fig. 4B, is shown on the next page. The authors are grateful to the Editor of International Journal of Oncology for allowing them this opportunity to publish a Corrigendum, and all the authors agree with its publication. Furthermore, the authors apologize to the readership for any inconvenience caused. [International Journal of Oncology 48: 2184­2196, 2016; DOI: 10.3892/ijo.2016.3428].

Role and mechanism of CD90+ fibroblasts in inflammatory diseases and malignant tumors.

Fibroblasts are highly heterogeneous mesenchymal stromal cells, and different fibroblast subpopulations play different roles. A subpopulation of fibroblasts expressing CD90, a 25-37 kDa glycosylphosphatidylinositol anchored protein, plays a dominant role in the fibrotic and pro-inflammatory state. In this review, we focused on CD90+ fibroblasts, and their roles and possible mechanisms in disease processes. First, the main biological functions of CD90+ fibroblasts in inducing angiogenesis and maintaining tissue homeostasis are described. Second, the role and possible mechanism of CD90+ fibroblasts in inducing pulmonary fibrosis, inflammatory arthritis, inflammatory skin diseases, and scar formation are introduced, and we discuss how CD90+ cancer-associated fibroblasts might serve as promising cancer biomarkers. Finally, we propose future research directions related to CD90+ fibroblasts. This review will provide a theoretical basis for the diagnosis and treatment CD90+ fibroblast-related disease.

Integrative Analysis Identified CD38 As a Key Node That Correlates Highly with Immunophenotype, Chemoradiotherapy Resistance, And Prognosis of Head and Neck Cancer.

Head and neck cancer (HNC) is mainly treated by surgery, radiotherapy, and adjuvant chemotherapy; however, the prognosis of some patients with HNC is poor because of radiotherapy and chemotherapy resistance. In recent years, anti­PD­1 monoclonal antibodies have shown certain efficacy, and a change of the tumor immune microenvironment is the main reason for the failure of HNC immunotherapy. The present study aimed to identify and verify that CD38, which is closely related to the prognosis of HNC, is a potential biological marker of radiotherapy and chemotherapy resistance and PD-L1 immunotherapy resistance via a comprehensive bioinformatic analysis in The Cancer Genome Atlas and Gene Expression Omnibus databases. According to the UALCAN database, the transcript level of CD38 in HNC was analyzed using cluster analysis, and the expression of CD38 mRNA in HNC was detected using the Oncomine database. The characteristics of CD38-related oncogenes were identified by gene cluster enrichment analysis in LinkedOmics. The R2 and SEER databases were used to further evaluate the prognostic significance of the CD38 gene in HNC using receiver operating characteristic curve analysis of Kaplan-Meier (KM) survival and the clinical characteristics of the subjects. The protein-protein interaction network of the top 50 genes showing significant positive correlations with CD38 in HNC was analyzed using STRING. Finally, we used a nasopharyngeal carcinoma (NPC) cell line to verify the biological function. The results showed that the levels of CD38 mRNA expression in patients with HNC were significantly higher than those in healthy controls. The levels of CD38 mRNA expression in patients with HNC of different ages, sexes, and races were significantly higher than those in the healthy controls. CD38 is an independent prognostic factor for HNC, and high expression of CD38 indicates poor prognosis. CD38 expression correlated positively with the markers of many kinds of immune cells, and correlated significantly with the expression of PD-L1. We found that the high expression of CD38 suggested a poor prognosis in the subgroup of tumors treated with chemotherapeutic drugs in the G1/S phase. We used HNC cell lines to verify that the high expression of CD38 promoted the proliferation of NPC cells and produced radiotherapy tolerance. Through comprehensive bioinformatics analysis, we suggested that CD38 is a key gene involved in radiotherapy, chemotherapy, and immune drug resistance in HNC. This study provides a reliable biomarker to predict the prognosis of patients with HNC and a reference for clinical comprehensive treatment of HNC. Individualization combined with CD38 monoclonal antibodies might provide a promising treatment strategy for this fatal disease, and this comprehensive treatment might reduce the damage to normal tissue and improve the prognosis and quality of life of patients with HNC.

Dendritic cell vaccines improve the glioma microenvironment: Influence, challenges, and future directions.

INTRODUCTION: Gliomas, especially the glioblastomas, are one of the most aggressive intracranial tumors with poor prognosis. This might be explained by the heterogeneity of tumor cells and the inhibitory immunological microenvironment. Dendritic cells (DCs), as the most potent in vivo functional antigen-presenting cells, link innate immunity with adaptive immunity. However, their function is suppressed in gliomas. Therefore, overcoming the dysfunction of DCs in the TME might be critical to treat gliomas. METHOD: In this paper we proposed the specificity of the glioma microenvironment, analyzed the pathways leading to the dysfunction of DCs in tumor microenvironment of patients with glioma, summarized influence of DC-based immunotherapy on the tumor microenvironment and proposed new development directions and possible challenges of DC vaccines. RESULT: DC vaccines can improve the immunosuppressive microenvironment of glioma patients. It will bring good treatment prospects to patients. We also proposed new development directions and possible challenges of DC vaccines, thus providing an integrated understanding of efficacy on DC vaccines for glioma treatment.

A pan-cancer analysis of copper homeostasis-related gene lipoyltransferase 1: Its potential biological functions and prognosis values.

As a key copper homeostasis-related molecule, lipoyltransferase 1 (LIPT1) is an essential enzyme for the activation of mitochondrial 2-ketoacid dehydrogenase, participating in fatty acylation. However, the biological significances of LIPT1 in the pan-cancer are unclear. Here, we comprehensively analyzed the functional characteristics of LIPT1 in human cancers and its roles in immune response. We found that LIPT1 was down-regulated in some cancers. And LIPT1 overexpression is associated with favorable prognosis in these patients, such as breast cancer, clear cell renal cell carcinoma, ovarian cancer and gastric cancer. We also explored the mutational status and methylation levels of LIPT1 in human cancers. Gene enrichment analysis indicated that abnormally expressed LIPT1 was significantly associated with immune cells infiltration, such as B cells, CD8+ T cells and cancer-associated fibroblast cells. The result from single cell sequencing reflected the important roles of LIPT1 in the regulation of several biological behaviors of cancer cells, such as DNA damage response and cell apoptosis. Taken together, our research could provide a comprehensive overview about the significances of LIPT1 in human pan-cancer progression, prognosis and immune.

Effect of CD38 on B-cell function and its role in the diagnosis and treatment of B-cell-related diseases.

CD38 is a multifunctional receptor and enzyme present on the surface of B lymphocytes, which can induce B lymphocytes proliferation and apoptosis by crosslinking related cytokines to affect the function of B cells, thus affecting immune regulation in humans and promoting tumorigenesis. The level of CD38 expression in B cells has become an important factor in the clinical diagnosis, treatment, and prognosis of malignant tumors and other related diseases. Therefore, studying the relationship between CD38 expression on the surface of B cells and the occurrence of the disease is of great significance for elucidating its association with disease pathogenesis and the clinical targeted therapy. In this paper, we review the effects of CD38 on B-cell activation, proliferation, and differentiation, and elaborate the functional role and mechanism of CD38 expression on B cells. We also summarize the relationship between the level of CD38 expression on the surface of B cells and the diagnosis, treatment, and prognosis of various diseases, as well as the potential use of targeted CD38 treatment for related diseases. This will provide an important theoretical basis for the scientific research and clinical diagnosis and treatment of B-cell-related diseases.

Erratum: Lactotransferrin expression is downregulated and affects the mitogen-activated protein kinase pathway in gastric cancer.

[This corrects the article DOI: 10.3892/ol.2015.3011.].

CD90 affects the biological behavior and energy metabolism level of gastric cancer cells by targeting the PI3K/AKT/HIF-1α signaling pathway.

CD90, also known as Thy-1 cell surface antigen, is located on human chromosome 11q23.3, and encodes a glycosylphosphatidylinositol-linked cell surface glycoprotein. CD90 serves a key role in malignancy by regulating cell proliferation, metastasis and angiogenesis. Gastric cancer is one of the most common types of malignancy. Patients with advanced gastric cancer have a poor prognosis. CD90 plays a key role in the occurrence and progression of gastric cancer. However, the molecular mechanism of CD90 in gastric cancer is currently unclear. In order to identify the molecular mechanism by which CD90 affects the biological behavior and energy metabolism of gastric cancer cells, the present study used Cell Counting Kit-8 assays, lactate concentration determination and ATP content determination. The results demonstrated that CD90 promotes proliferation and inhibits senescence in gastric cancer cells. In addition, CD90 enhanced the invasion and migration abilities of AGS gastric cancer cells. Overexpression of CD90 resulted in the accumulation of intracellular lactic acid in AGS cells. CD90 upregulated lactate dehydrogenase levels and increased the NADPH/NADP+ ratio in AGS cells. CD90 overexpression decreased the ATP concentration in AGS cells. PI3K, PDK1, phosphorylated-AKT-Ser473, HIF-1α, MDM2 and SIRT1 levels were upregulated in CD90-overexpressing AGS cells, compared with AGS cells transfected with the empty vector. In contrast, PTEN, p53, SIRT2, SIRT3 and SIRT6 were downregulated. The results indicate that CD90 affects the biological behavior and levels of energy metabolism of gastric cancer cells by targeting the PI3K/AKT/HIF-1α signaling pathway.

CD38 is involved in cell energy metabolism via activating the PI3K/AKT/mTOR signaling pathway in cervical cancer cells.

In contrast to normal cells, cancer cells typically undergo metabolic reprogramming. Studies have shown that oncogenes play an important role in this metabolic reprogramming. CD38 is a multifunctional transmembrane protein that is expressed abnormally in a variety of tumor types. To investigate the effect and possible mechanism of CD38 in cervical cancer cells and to provide a new therapeutic target for the treatment of cervical cancer, the present study identified that CD38 is involved in regulating cell metabolism in cervical cancer cells. Liquid chromatography­tandem mass spectrometry and bioinformatic analyses revealed that differentially abundant proteins in CD38­overexpressed cervical cancer cells (CaSki­CD38 and HeLa­CD38) are predominantly involved in glycolytic pathways, oxidative phosphorylation and the NAD/NADH metabolic process. Further experiments using an ATP test kit and lactate test kit revealed that CD38 promotes glucose consumption, increases lactate accumulation and increases ATP production. In addition, CD38 increases the phosphorylation of phosphatidylserine/threonine kinase (AKT), mechanistic target of rapamycin (mTOR) and phosphatidylinositol­4,5­bisphosphate 3­kinase (PI3K), which play a key role in tumor metabolism. Furthermore, it was found that the energy metabolism of cervical cancer cells was inhibited following treatment with the mTOR inhibitor rapamycin. In conclusion, the results of the present study suggested that CD38 regulates the metabolism of cervical cancer cells by regulating the PI3K/AKT/mTOR pathway, which may be a candidate target for the treatment of cervical cancer.

YMO1 suppresses invasion and metastasis by inhibiting RhoC signaling and predicts favorable prognosis in hepatocellular carcinoma.

Previous studies have shown that 4.1 proteins, which are deregulated in many cancers, contribute to cell adhesion and motility. Yurt/Mosaic eyes-like 1 (YMO1) is a member of 4.1 protein family but it is unclear whether YMO1 plays a role in tumor invasion. This study aimed to investigate the effects of YMO1 on hepatocellular carcinoma (HCC) and attempted to elucidate the underlying molecular mechanisms. YMO1 expression in HCC tissues and its correlation with clinicopathological features and postoperative prognosis was analyzed. The results showed that YMO1 was down-regulated in the highly metastatic HCC cell line and in human tumor tissues. Underexpression of YMO1 indicated poor prognosis of HCC patients. Restoration of YMO1 expression caused a significant decrease in cell migration and invasiveness in vitro. In vivo study showed that YMO1 reduced liver tumor invasion and metastasis in xenograft mice. YMO1 directly inhibited RhoC activation. YMO1 expression in HCC was regulated by PAX5. Analysis of YMO1 expression levels in human HCC patients revealed a significant correlation of YMO1 expression with PAX5 and RhoC. Our findings revealed that YMO1 predicts favorable prognosis and the data suggest that YMO1 suppresses tumor invasion and metastasis by inhibiting RhoC activity.

Expression levels of JNK associated with polymorphic lactotransferrin haplotypes in human nasopharyngeal carcinoma.

Lactotransferrin (LTF), a member of the transferrin family, serves a role in the innate immune response and is involved in anti-inflammatory, anti-microbial and anti-tumor activity. Alterations in the LTF gene are associated with an increased incidence of cancer. The LTF gene is polymorphic, and several common alleles may be observed in the general population. Our previous study identified a lower rate of occurrence of the 'A-G-G-T' haplotype (constructed with rs1126477, rs1126478, rs2073495 and rs9110) in nasopharyngeal carcinoma (NPC) patients compared with controls. In the present study, in order to elucidate a possible mechanism of LTF-mediated anti-tumor activity in NPC, the protein profiles of NPC and non-tumorous nasopharyngeal epithelium tissues with/without the 'A-G-G-T' haplotype were constructed using LTQ Orbitrap technology. The results revealed that c-Jun N-terminal kinase 2 (JNK2) was highly expressed in NPC tissues and non-tumor nasopharyngeal epithelium tissues without the 'A-G-G-T' haplotype. These results were confirmed by western blot analysis. Furthermore, microRNA (miRNA) microarray analysis was conducted to investigate the differential miRNA profiles of NPC and non-tumor nasopharyngeal epithelium tissues with/without the 'A-G-G-T' haplotype. It was observed that hsa-miR-1256 and hsa-miR-659, which are potentially targeted to the JNK2 gene, were downregulated in NPC tissues without the 'A-G-G-T' haplotype. Hsa-miR-298, another miRNA potentially targeted to the JNK2 gene, was downregulated in non-tumor nasopharyngeal epithelium tissues without the 'A-G-G-T' haplotype. In summary, these results suggested that the expression levels of JNK2 may be associated with polymorphic LTF haplotypes in human NPC.

CXCR1 promotes malignant behavior of gastric cancer cells in vitro and in vivo in AKT and ERK1/2 phosphorylation.

CXCR1 is a member of the chemokine receptor family, which was reported to play an important role in several cancers. The present study investigated the influence of CXCR1 stable knockdown or overexpression on the malignant behavior of gastric cancer cells in vitro and in vivo and the potential mechanisms. MKN45 and BGC823 cells were stably transfected with plasmid pYr-1.1-CXCR1-shRNA (knockdown) and pIRES2-ZsGreen1-CXCR1 (overexpression), respectively. Malignant behavior was evaluated in vitro for changes in proliferation by MTT and colony forming assays; cell cycle and apoptosis by flow cytometry; and migration and invasion using transwell and wound-healing assays. Proliferation, cell cycle, apoptosis, migration and invasion-related signaling molecule expression were measured by real-time RT-PCR and western blot analysis. CXCR1 knockdown and overexpressing xenografts were monitored for in vivo tumor growth. Stable knockdown of CXCR1 inhibited MKN45 cell proliferation, migration and invasion, but were reversed in BGC823 cells stably overexpressing CXCR1. In addition, MKN45 cells stably transfected with CXCR1 shRNA inhibited AKT and ERK1/2 phosphorylation, protein expression of cyclin D1, EGFR, VEGF, MMP-9, MMP-2 and Bcl-2, and increased protein expression of Bax and E-cadherin (all P<0.05). In vivo CXCR1-shRNA-MKN45 cells transplanted into nude mice formed smaller tumors than non-transfected or scrambled-shRNA cells (both P<0.05). In contrast BGC823 cells overexpressing CXCR1 formed larger tumors in mice than cells carrying an empty expression plasmid or non-transfected cells (both P<0.05). CXCR1 promoted gastric cancer cell proliferation, migration and invasion. The present study provides preclinical data to support CXCR1 as a novel therapeutic target for gastric cancer.

Repertaxin, an inhibitor of the chemokine receptors CXCR1 and CXCR2, inhibits malignant behavior of human gastric cancer MKN45 cells in vitro and in vivo and enhances efficacy of 5-fluorouracil.

Chemokine-mediated activation of G protein-coupled receptors CXCR1/2 promotes tumor growth, invasion, inflammation and metastasis. Repertaxin, a CXCR1/2 small-molecule inhibitor, has been shown to attenuate many of these tumor-associated processes. The present study aimed to investigate the effects of repertaxin alone and in combination with 5-fluorouracil (5-FU) on the malignant behavior of gastric cancer and the potential mechanisms. Gastric cancer MKN45 cells were treated in vitro with repertaxin and 5-FU, either alone or in combination. MTT and colony formation assay were performed to assess proliferation. Cell cycle progression and apoptosis was completed by flow cytometry. Migration and invasion were also assessed by transwell and wound-healing assay. Western blot analysis and quantitative RT-PCR were performed to determine expression of signaling molecules. MKN45 cells were also grown as xenografts in nude mice. Mice were treated with repertaxin and 5-FU, and tumor volume and weight, angiogenesis, proliferation and apoptosis were monitored. Combination of repertaxin and 5-FU inhibited MKN45 cell proliferation and increased apoptosis better than either agent alone. Similarly, enhanced effect of the combination was also observed in migration and invasion assays. The improved effect of repertaxin and 5-FU was also observed in vivo, as xenograft models treated with both compounds exhibited significantly decreased tumor volume and increased apoptosis. In conclusion, repertaxin inhibited malignant behavior of human gastric cancer MKN45 cells in vitro and in vivo and enhances efficacy of 5-fluorouracil. These data provide rationale that targeting CXCR1/2 with small molecule inhibitors may enhance chemotherapeutic efficacy for the treatment of gastric cancer.

CD38 is a putative functional marker for side population cells in human nasopharyngeal carcinoma cell lines.

Cancer stem cells (CSCs) are thought to be responsible for cancer progression and therapeutic resistance but identification of this subpopulation requires selective markers. Fortunately, side population (SP) cells analysis brings a novel method to CSCs study. In this study, we identified SP cells, which are demonstrated rich in CSCs, in four nasopharyngeal carcinoma (NPC) cell lines. We investigated SP cells from HK-1 NPC cell line and showed CSCs characteristics in this subpopulation. SP cells displayed greater proliferation and invasion and expressed high levels of CSCs markers than NSP cells. Furthermore, our microRNA microarray analysis of SP versus NSP cells revealed that CD38-related miRNAs were down-regulated in SP cell, but the mRNA and protein level of CD38 were highly expressed in SP cells. We further searched for molecules interacting with CD38 and identified ZAP70, which was also well expressed in SP cells at both mRNA and protein levels. Our results uncover a CD38 pathway that may regulate the proliferation and migration of SP cells from HK-1 NPC cell line.

Dysregulation of the PI3K/Akt signaling pathway affects cell cycle and apoptosis of side population cells in nasopharyngeal carcinoma.

Increasing evidence has suggested that certain types of cancer possess their own stem-like cells, and that one subset of these cells, termed the side population (SP), may have an important role in tumorigenesis and cancer therapy. However, the molecular mechanisms underlying the modulation of SP cells in nasopharyngeal carcinoma (NPC) have remained elusive. In the present study, it was hypothesized that dysregulation of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt signaling pathway may influence SP and non-SP (NSP) phenotype. SP cells from the HK-1 NPC cell line were identified, and cancer stem cell markers were found to be highly expressed in SP cells compared with that of NSP cells. Freshly sorted SP cells demonstrated a significant increase in the proportion of cells in G0/G1 phase, while the majority of NSP cells were in the proliferative phase. Following 48 h of culture subsequent to cell sorting, the differences in cell cycle distribution between the SP and NSP cells converged. In addition, the apoptotic ratio of NSP cells was higher than that of SP cells at 24 h following sorting, but had no significant differences 48 h following sorting. To elucidate the potential mechanism mediating the cell cycle and apoptosis in SP cells, the expression levels of key molecules in the PI3K/Akt signaling pathway were evaluated. PI3K and Akt were upregulated, while 14-3-3σ protein was downregulated in SP cells when freshly sorted (0 h). However, there was no significant difference in the expression of these molecules between SP and NSP cells following 48 h of culture. These results suggested that dysregulation of the PI3K/Akt signaling pathway may be associated with the cell cycle and apoptosis of SP cells in NPC. However, further investigation is required to elucidate the detailed mechanisms underlying these effects.

Lactotransferrin expression is downregulated and affects the mitogen-activated protein kinase pathway in gastric cancer.

Gastric cancer (GC) is the second leading cause of cancer-associated mortality worldwide. In advanced and metastatic GC, conventional chemotherapy results in limited efficacy and the average survival rate is currently approximately 10 months. Dysregulated activation of numerous genes, including zinc finger, DHHC-type containing 14; caspase-associated recruitment domain-containing protein; and Ras association domain family member 10, have been implicated in GC. The tumor suppressor function of lactotransferrin (LTF) has been reported in a variety of tumors, including GC, nasopharyngeal carcinoma (NPC) and prostate cancer. However, the mechanism of the tumor suppressor function of LTF in GC remains unclear. In the present study, the expression levels of LTF in patient GC tissue samples were investigated using reverse transcription-quantitative polymerase chain reaction, and it was demonstrated that the LTF mRNA expression level in GC tissue samples was reduced by ~20-fold compared with the adjacent non-cancerous tissues (t=4.56, P<0.01). A similar trend in LTF protein expression was observed by western blot analysis. Furthermore, the present study demonstrated that the mitogen-activated protein kinase (MAPK) signaling pathway intermediates p38, c-Jun N-terminal kinase (JNK) and c-Jun were highly expressed in GC tissue samples, and indicated that LTF downregulation may be associated with the dysregulation of the MAPK signaling pathway in GC tissues. In addition, the present study indicated that LTF overexpression reduced the expression of p38, JNK2 and c-Jun in the GC cell line, SGC7901. The present study demonstrates that LTF expression is downregulated in GC tissues and that LTF may serve an important role in the dysregulation of the MAPK signaling pathway.

Epidermal growth factor-like domain-containing protein 7 (EGFL7) enhances EGF receptor-AKT signaling, epithelial-mesenchymal transition, and metastasis of gastric cancer cells.

Epidermal growth factor-like domain-containing protein 7 (EGFL7) is upregulated in human epithelial tumors and so is a potential biomarker for malignancy. Indeed, previous studies have shown that high EGFL7 expression promotes infiltration and metastasis of gastric carcinoma. The epithelial-mesenchymal transition (EMT) initiates the metastatic cascade and endows cancer cells with invasive and migratory capacity; however, it is not known if EGFL7 promotes metastasis by triggering EMT. We found that EGFL7 was overexpressed in multiple human gastric cancer (GC) cell lines and that overexpression promoted cell invasion and migration as revealed by scratch wound and transwell migration assays. Conversely, shRNA-mediated EGFL7 knockdown reduced invasion and migration. Furthermore, EGFL7-overexpressing cells grew into larger tumors and were more likely to metastasize to the liver compared to underexpressing CG cells following subcutaneous injection in mice. EGFL7 overexpression protected GC cell lines against anoikis, providing a plausible mechanism for this enhanced metastatic capacity. In excised human gastric tumors, expression of EGFL7 was positively correlated with expression levels of the mesenchymal marker vimentin and the EMT-associated transcription repressor Snail, and negatively correlated with expression of the epithelial cell marker E-cadherin. In GC cell lines, EGFL7 knockdown reversed morphological signs of EMT and decreased both vimentin and Snail expression. In addition, EGFL7 overexpression promoted EGF receptor (EGFR) and protein kinase B (AKT) phospho-activation, effects markedly suppressed by the EGFR tyrosine kinase inhibitor AG1478. Moreover, AG1478 also reduced the elevated invasive and migratory capacity of GC cell lines overexpressing EGFL7. Collectively, these results strongly suggest that EGFL7 promotes metastasis by activating EMT through an EGFR-AKT-Snail signaling pathway. Disruption of EGFL7-EGFR-AKT-Snail signaling may a promising therapeutic strategy for gastric cancer.

Proteomics-based analysis of differentially expressed proteins in the CXCR1-knockdown gastric carcinoma MKN45 cell line and its parental cell.

C-X-C chemokine receptor types 1 (CXCR1), a cell-surface G-protein-coupled receptor has been found to be associated with tumorigenesis, development, and progression of some tumors. Previously, we have found that CXCR1 overexpression is associated with late-stage gastric adenocarcinoma. We also have demonstrated that knockdown of CXCR1 could inhibit cell proliferation in vitro and in vivo. In this study, we compared the changes of protein expression profile between gastric carcinoma MKN45 cell line and CXCR1-knockdown MKN45 cell line by 2D electrophoresis. Among the 101 quantified proteins, 29 spots were significantly different, among which 13 were down-regulated and 16 were up-regulated after CXCR1 knockdown. These proteins were further identified by mass spectrometry analysis. Among them, several up-regulated proteins such as hCG2020155, Keratin8, heterogeneous nuclear ribonucleoprotein C (C1/C2), and several down-regulated proteins such as Sorcin, heat shock protein 27, serpin B6 isoform b, and heterogeneous nuclear ribonucleoprotein K were confirmed. These proteins are related to cell cycle, the transcription regulation, cell adherence, cellular metabolism, drug resistance, and so on. These results provide an additional support to the hypothesis that CXCR1 might play an important role in proliferation, invasion, metastasis, and prognosis, and drug resistance of gastric carcinoma.