Expression of VEGF, EGFR, and IL-6 in gastric adenomas and adenocarcinomas by endoscopic submucosal dissection

Spontaneous Regression of a Large Gastric Adenoma Following Gynecologic Surgery

Gastric adenomas are defined as polypoid lesions of neoplastic epithelium in the stomach. They are rare, occurring much less frequently than fundic gland polyps and hyperplastic polyps, and are typically associated with mucosal atrophy and intestinal metaplasia. Gastric adenomas also carry a risk of malignant transformation. We report a case of a 66-year-old woman with a gastric adenoma of the corpus found during a preoperative esophagogastroduodenoscopy before abdominal surgery for an ovarian tumor. The patient demonstrated spontaneous regression of her gastric adenoma 14 months after her initial endoscopy and subsequent hysterectomy with salpingo-oophorectomy without undergoing endoscopic resection or any other intervention. To our knowledge, this is the first well-documented case of spontaneous regression of a gastric adenoma.

Endothelin-A receptor in gastric cancer and enhanced antitumor activity of trastuzumab in combination with the endothelin-A receptor antagonist ZD4054

Endothelin-A receptor (ETAR) is overexpressed in cancers and can function through transactivation of the epidermal growth factor receptor. We explored ETAR in gastric cancer and investigated the antitumor effect of trastuzumab in combination with the ETAR antagonist ZD4054. The expression of ETAR was significantly correlated with the expression of vascular endothelial growth factor. Univariate and multivariate analyses further showed that ETAR expression correlated with reduced survival in gastric cancer patients. In vitro, ZD4054 increased the antiproliferative effect of trastuzumab in gastric cancer cell lines. Moreover, the addition of ZD4054 to trastuzumab significantly increased apoptosis in gastric cancer cell lines. In vivo, tumor growth was considerably inhibited by treatment with ZD4054 and trastuzumab, and the tumor volume in the trastuzumab and ZD4054 combination group was smaller than in the other groups. The detection of ETAR could help predict the prognosis of gastric cancer patients. Additionally, this study provides support for the therapeutic use of the combination of ZD4054 and trastuzumab as an anticancer treatment, especially for gastric cancer.

Resolution of Gastric Cancer-Promoting Inflammation: A Novel Strategy for Anti-cancer Therapy

The connection between inflammation and cancer was initially recognized by Rudolf Virchow in the nineteenth century. During the last decades, a large body of evidence has provided support to his hypothesis, and now inflammation is recognized as one of the hallmarks of cancer, both in etiopathogenesis and ongoing tumor growth. Infection with the pathogen Helicobacter pylori is the primary causal factor in 90% of gastric cancer (GC) cases. As we increase our understanding of how chronic inflammation develops in the stomach and contributes to carcinogenesis, there is increasing interest in targeting cancer-promoting inflammation as a strategy to treat GC. Moreover, once cancer develops and anti-cancer immune responses are suppressed, there is evidence of a substantial shift in the microenvironment and new targets for immune therapy emerge. In this chapter, we provide insight into inflammation-related factors, including T lymphocytes, macrophages, pro-inflammatory chemokines, and cytokines, which promote H. pylori-associated GC initiation and growth. While intervening with chronic inflammation is not a new practice in rheumatology or gastroenterology, this approach has not been fully explored for its potential to prevent carcinogenesis or to contribute to the treatment of GC. This review highlights current and possible strategies for therapeutic intervention including (i) targeting pro-inflammatory mediators, (ii) targeting growth factors and pathways involved in angiogenesis in the gastric tumor microenvironment, and (iii) enhancing anti-tumor immunity. In addition, we highlight a significant number of clinical trials and discuss the importance of individual tumor characterization toward offering personalized immune-related therapy.

Systematic literature review of IL-6 as a biomarker or treatment target in patients with gastric, bile duct, pancreatic and colorectal cancer

Gastrointestinal cancer (GI) is a major health problem. Patients with gastric, pancreatic, colorectal, bile duct and gall bladder cancer often have advanced disease at the time of diagnosis and are generally difficult to cure, resulting in a dismal prognosis for most patients. Inflammation plays an important role in the development and growth of cancer, which has led to a growing interest in the pro-inflammatory cytokine interleukin 6 (IL-6). The aim of the present review was to evaluate the clinical use of IL-6 as a biomarker or therapeutic target in patients with GI cancer. We did a systematic review of studies (1993-2018), to assess the clinical use of IL-6 as a diagnostic, prognostic or predictive tumor biomarker or as a potential therapeutic target. This review includes 48 studies and 5316 patients. Circulating IL-6 levels appear to be an independent prognostic biomarker in patients with GI cancer, with high IL-6 levels associated with short overall survival (OS). The results for colorectal cancer were too ambiguous to give conclusive results. IL-6 seemed to be a marker for some of the clinical characteristics of GI cancer, and may have a role in the diagnostic workup in general practice. No published studies have examined the use of IL-6 as a therapeutic target in pancreatic, gastric, bile duct or colorectal cancer. In conclusion, high circulating IL-6 was associated with short OS in most studies in GI cancer patients. Whether inhibition of IL-6 would decrease GI cancer symptoms and increase quality of life is unknown.

Cytokine expression associated with Helicobacter pylori and Epstein-Barr virus infection in gastric carcinogenesis

Helicobacter pylori and Epstein-Barr virus (EBV) infection, and associated cytokines are involved in gastric carcinogenesis. We investigated the expression of these cytokines and their relationship with clinicopathological characteristics. The study included specimens from 207 patients with gastric adenocarcinoma, 56 with chronic gastritis, 32 with metaplasia, and 30 with low-grade epithelial dysplasia. Tissue microarrays were constructed and immunohistochemical staining for IL-1β, IL-6, IL-10, IL-17, p16, p21, TNF-α, and TNFR1 was performed. EBV and H. pylori infection status was determined. IL-1β, IL-6, IL-17, p16, and p21 protein expression was significantly higher in adenocarcinoma cases than in the other cases (p < 0.05). EBV was only noted in adenocarcinoma (13 cases, 6.3%). The H. pylori infection rate in adenocarcinoma was significantly higher than that in the other cases (p < 0.005). IL-6 expression was associated with improved survival (p < 0.05), whereas IL-17 expression was associated with decreased survival (p < 0.05). IL-6 expression was inversely associated with angioinvasion, and disease stage (p < 0.05), whereas IL-17 expression was associated with disease stage (p < 0.05). IL-10 expression was correlated with IL-1β and TNF-α expression, and p16 expression was correlated with IL-17 and EBV status. Our results indicate that IL-6 and IL-17 are associated with gastric carcinogenesis and may be considered prognostic factors.

Matrix Metalloproteinases and Their Tissue Inhibitors in Comparison to Other Inflammatory Proteins in Gastric Cancer (GC)

Gastric cancer (GC) remains a major cause of cancer-related deaths worldwide. The lack of management strategies for the diagnosis of GC in patients gives rise to the challenging questions about the new tumor markers for GC. Developing malignant process may induce local and systemic inflammatory responses. Cancer-associated inflammation is characterized by the infiltration of immune cells. Thus, the inflammation-related proteins, such as cytokines, chemokines, and selected matrix metalloproteinases, may facilitate the growth, proliferation, and migration of tumor cells, including GC. Based on our previous findings, we assessed the significance of various inflammatory mediators as candidates for tumor markers of GC.

Ablation of galectin-3 induces p27(KIP1)-dependent premature senescence without oncogenic stress

Premature senescence induced by oncogenic stimuli or tumor suppressor activation plays opposing roles in tumorigenesis. Here, we propose that galectin-3, a β-galactoside-binding lectin, regulates premature senescence without oncogenic stress. We detected premature senescence, decreased Skp2, and increased p27^KIP1 expression in galectin-3 knockout MEFs and galectin-3-depleted gastric cancer cells. Interestingly, galectin-3 depletion did not affect other senescence inducers such as p14^ARF, p16^INK4A, and p21^WAF1/CIP1, suggesting that galectin-3-regulated senescence is p27^KIP1 dependent. We demonstrate that galectin-3 depletion decreases retinoblastoma protein (Rb) phosphorylation (Ser780, Ser807/811), cyclin D1 and CDK4 expression, and E2F1 transcriptional activation. Galectin-3 directly interacts with the cyclin D1/CDK4 complex and promotes hyperphosphorylation of Rb. It also blocks the inhibition of E2F1 transcription, thereby increasing the expression of Skp2 and reducing the stability of p27^KIP1 to promote the proliferation of gastric cancer cells. Xenograft mice with galectin-3-depleted gastric cancer cells display tumor growth retardation that is reversed by Skp2 overexpression. Increased expression of galectin-3 is also associated with the advanced TNM (tumor, lymph node, metastasis) system, clinicopathological stage, and lymph node metastases. The probability of survival was significantly decreased in gastric cancer patients with galectin-3^high p27^KIP1-lowcells. Taken together, our results show that galectin-3 may accelerate gastric tumorigenesis by inhibiting premature senescence.

IL-6 and related cytokines as the critical lynchpins between inflammation and cancer

Inflammatory responses play pivotal roles in cancer development, including tumor initiation, promotion, progression, and metastasis. Cytokines are now recognized as important mediators linking inflammation and cancer, and are therefore potential therapeutic and preventive targets as well as prognostic factors. The interleukin (IL)-6 family of cytokines, especially IL-6 and IL-11, is highly up-regulated in many cancers and considered as one of the most important cytokine families during tumorigenesis and metastasis. This review discusses molecular mechanisms linking the IL-6 cytokine family to solid malignancies and their treatment.

Signal transducer and activator of transcription 3 signaling upregulates fascin via nuclear factor-κB in gastric cancer: Implications in cell invasion and migration

Fascin protein plays important roles in tumor metastasis and is prognostically relevant to human gastric cancer (GC). However, its role in the development and progression of GC has not been comprehensively investigated. In the present study, results revealed that upregulation of fascin by interleukin-6 promotes GC cell migration and invasion in a signal transducer and activator of transcription 3 (STAT3)-dependent manner in MKN45 cells. Furthermore, STAT3 directly regulated fascin expression and nuclear factor-κB (NF-κB) bound to the fascin promoter in a STAT3-dependent and Notch-independent manner. Therefore, results demonstrate that STAT3 and NF-κB are required for upregulation of fascin and for cell migration and invasion in MKN45 cells. Effects of the treatments on cell signaling were detected by qPCR, western blot analysis and chromatin immunoprecipitation (ChIP) assay. Cell migration and invasion were analyzed using in vitro scratch wound healing assay, transwell and Matrigel assays, and xenograft model. In addition, the STAT3-NF-κB-fascin signaling axis is identified as a therapeutic target for blocking GC cell invasion and migration.

Interleukin 6 gene polymorphism -174 is associated with the diffuse type gastric carcinoma

The aim of this study was to assess the significance of the interleukin 6 gene polymorphism -174 in gastric cancer risk. The interleukin 6 -174 G/C (rs1800795) gene polymorphisms was analyzed in gastric cancer, peptic ulcer, and nonulcer dyspepsia patients and in healthy control subjects and the data were correlated with the histopathological features of the patients' biopsies. The interleukin 6 -174 GG and GC genotypes have been previously associated with high interleukin 6 serum levels. We discovered that the interleukin 6 -174 GG and GC genotypes are associated with an increased risk of the diffuse histologic subtype of gastric carcinomas (OR: 6.809, P = 0.034), but absent in the intestinal type carcinomas (OR: 1.109, P = 0.908). No significant associations with peptic ulcer, gastric atrophy, or intestinal metaplasia were seen. Our results demonstrate that the interleukin 6 -174 GG and GC genotypes increase the risk of the diffuse type gastric carcinoma, but not the intestinal type gastric carcinoma or its precursor conditions, including atrophy or intestinal metaplasia. Thus, interleukin 6 seems to be an important carcinogenetic factor in the diffuse type gastric adenocarcinoma and its carcinogenetic effect could be noninflammatory.

Interleukin-6 mediates epithelial-stromal interactions and promotes gastric tumorigenesis

Interleukin-6 (IL-6) is a pleiotropic cytokine that affects various functions, including tumor development. Although the importance of IL-6 in gastric cancer has been documented in experimental and clinical studies, the mechanism by which IL-6 promotes gastric cancer remains unclear. In this study, we investigated the role of IL-6 in the epithelial–stromal interaction in gastric tumorigenesis. Immunohistochemical analysis of human gastritis, gastric adenoma, and gastric cancer tissues revealed that IL-6 was frequently detected in the stroma. IL-6–positive cells in the stroma showed positive staining for the fibroblast marker α-smooth muscle actin, suggesting that stromal fibroblasts produce IL-6. We compared IL-6 knockout (IL-6^−/−) mice with wild-type (WT) mice in a model of gastric tumorigenesis induced by the chemical carcinogen N-methyl-N-nitrosourea. The stromal fibroblasts expressed IL-6 in tumors from WT mice. Gastric tumorigenesis was attenuated in IL-6^−/− mice, compared with WT mice. Impaired tumor development in IL-6^−/− mice was correlated with the decreased activation of STAT3, a factor associated with gastric cancer cell proliferation. In vitro, when gastric cancer cell line was co-cultured with primary human gastric fibroblast, STAT3–related genes including COX-2 and iNOS were induced in gastric cancer cells and this response was attenuated with neutralizing anti-IL-6 receptor antibody. IL-6 production from fibroblasts was increased when fibroblasts were cultured in the presence of gastric cancer cell–conditioned media. IL-6 production from fibroblasts was suppressed by an interleukin-1 (IL-1) receptor antagonist and siRNA inhibition of IL-1α in the fibroblasts. IL-1α mRNA and protein were increased in fibroblast lysate, suggesting that cell-associated IL-1α in fibroblasts may be involved. Our results suggest the importance of IL-6 mediated stromal-epithelial cell interaction in gastric tumorigenesis.

Acceleration of gastric tumorigenesis through MKRN1-mediated posttranslational regulation of p14ARF

Background

We investigated whether Makorin ring finger protein 1 (MKRN1), an E3 ligase, affects p14ARF-associated cellular senescence and tumorigenesis by posttranslational modification in gastric tumorigenesis.

Methods

A link between MKRN1 and ARF was examined in MKRN1 null mouse embryonic fibroblasts (MEFs) and in human fibroblasts and gastric cancer cells by silencing MKRN1 using small interfering RNA (siRNA) and short hairpin RNA (shRNA). Ubiquitination and proteasomal degradation assays were used to assess p14ARF degradation associated with MKRN1. MKRN1 and p14ARF expression levels were analyzed with immunohistochemistry in malignant and normal tissues from gastric cancer patients and with χ² tests. The tumor growth of gastric cancer cells stably expressing MKRN1 shRNA, p14ARF shRNA, or both was examined in mouse xenograft models (n = 4–6) and analyzed with unpaired t tests. All statistical tests were two-sided.

Results

MKRN1 knockout MEFs exhibited premature senescence and growth retardation with increased p19ARF protein expression. Similar results were obtained for human fibroblasts or gastric cancer cell lines by MKRN1 knockdown. Biochemical analyses confirmed that MKRN1 targets p14ARF for ubiquitination and subsequent proteasome-dependent degradation. A statistically significant association was shown between MKRN1 overexpression and p14ARF underexpression (P = .016). Xenograft analyses using p53-functional AGS or -dysfunctional SNU601 cells displayed statistically significant tumor growth retardation by silencing MKRN1, which was reversed under depletion of p14ARF (AGS cells, MKRN1 knockdown tumors vs MKRN1 and p14ARF knockdown tumors: 164.6 vs 464.8mm³, difference = 300.2mm³, 95% CI = 189.1 to 411.3mm³, P < .001).

Conclusions

We demonstrated that MKRN1 functions as a novel E3 ligase of p14ARF and that it potentially regulates cellular senescence and tumorigenesis in gastric cancer.

Aberrant expression of EphA3 in gastric carcinoma: correlation with tumor angiogenesis and survival

BACKGROUND

EphA3, a member of the Eph receptor tyrosine kinases, plays important roles in tumor angiogenesis and progression. However, the function of EphA3 in solid tumors has not been widely studied. We aimed to explore EphA3 expression in gastric carcinoma and analyze its role as a potential prognostic factor.

METHODS

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess EphA3 mRNA in a normal gastric mucosa cell line and carcinoma cell lines. Immunohistochemistry for EphA3 and vascular endothelial growth factor (VEGF) was performed in 318 cases of gastric carcinoma. CD34 immunohistochemical staining was used for microvessel density (MVD) counting. Western blotting was used to analyze EphA3 expression in the cell lines and to determine the expression of EphA3 and VEGF in 75 cases of gastric carcinoma and matched normal mucosa.

RESULTS

EphA3 mRNA and protein expression was significantly higher in gastric cancer than that in normal mucosa (all P < 0.001). EphA3 was significantly correlated with TNM stage and poor prognosis (all P < 0.001). Multivariate analysis showed that EphA3 had an independent effect on survival (P = 0.037). EphA3 was positively correlated with VEGF (P < 0.001), and MVD (P < 0.001). According to Western blot analysis, both EphA3 and VEGF expression were significantly higher in carcinoma than that in normal mucosa (all P < 0.001). A positive correlation was observed between EphA3 and VEGF expression in cancer (P < 0.001, r = 0.513).

CONCLUSIONS

EphA3 may play important roles in the angiogenesis and prognosis of gastric carcinoma, and thus may become a useful target for therapeutic intervention and a potential indicator for clinical assessment of tumor prognosis.

Prognostic significance of vascular endothelial growth factor expression in gastric carcinoma: a meta-analysis

PURPOSE

The purpose of this study was to comprehensively and quantitatively summarize available evidences for the use of VEGF protein to evaluate the clinicopathological and prognostic role of VEGF expression in Asian patients with gastric cancer.

METHOD

Searches were applied to MEDLINE, EMBASE, and the Cochrane Library databases until June 2010, without language restrictions. A meta-analysis was performed to clarify the impact of VEGF expression on clinicopathological parameters or over survival (OS) in gastric cancer.

RESULTS

Our combined results showed that VEGF expression in Asian patients with gastric cancer was significantly higher in the case-control studies (1,194 patients and 1,618 controls) (odds ratio [OR] = 112.41, 95% confidence interval [CI] = 64.12-197.06). All the analyses estimated favored a stronger link between the high VEGF expression and the poor 5-year overall survival (1,236 patients) (risk ratio [RR] = 2.45, 95% CI = 2.11-2.83, P = 0.000). When stratifying the studies by the pathological variables, the depth of invasion (3,094 patients) (OR = 1.95, 95% CI = 1.40-2.71, P = 0.000), lymph node metastasis (3,240 patients) (OR = 1.82, 95% CI = 1.29-2.57, P = 0.001), distant metastasis (1,980 patients) (OR = 2.76, 95% CI = 1.22-6.25, P = 0.015), vascular invasion (1,803 patients) (OR = 2.61, 95% CI = 2.09-3.27, P = 0.000), and TNM stage (1,819 patients) (OR = 1.92, 95% CI = 1.57-2.36, P = 0.000) provided significant prognostic information.

CONCLUSION

Our results indicate that VEGF can potently predict the overall survival in Asian patients with gastric cancer. Importantly, VEGF may be converted from candidate to the routine clinical setting for clinicians to predict the outcome of single patient with gastric carcinoma.

Comparison between clinical significance of serum proinflammatory proteins (IL-6 and CRP) and classic tumor markers (CEA and CA 19-9) in gastric cancer

Gastric cancer (GC) is a second most common cause of cancer-related death and represents an inflammation-driven malignancy. It has been suggested that interleukin 6 (IL-6) and C-reactive protein (CRP) play a potential role in the growth and progression of GC. The aim of the present study was to compare clinical significance of IL-6 and CRP with classic tumor markers—carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) in GC patients. The study included 92 patients with GC and 70 healthy subjects. The serum concentrations of IL-6, CEA and CA 19-9 were determined using immunoenzyme assays, whereas CRP using immunoturbidimetric method. We defined the diagnostic criteria and prognostic value for proteins tested. In GC patients, the serum concentrations of all the proteins tested were significantly higher than in healthy subjects. The IL-6, CEA and CA 19-9 levels correlated with nodal metastases, while CRP with tumor stage, gastric wall invasion, presence of nodal and distant metastases. Diagnostic sensitivity of IL-6 was higher (85%) than those of other markers (CRP 66%, CA 19-9 34%, CEA 22%) and increased in combined use with CRP or CEA (88%). The area under ROC curve for IL-6 was larger than those of CRP and classic tumor markers (CEA and CA 19-9). None of the proteins tested was independent prognostic factor for the survival of GC patients. Our findings indicate better usefulness of serum proinflammatory proteins—IL-6 and CRP than classic tumor markers—CEA and CA 19-9 in the diagnosis of GC.