Reciprocal Interactions Between Apelin and Noncoding RNAs in Cancer Progression.

ObjectiveThe aim of this study was to investigate epidermal growth factor receptor (EGFR) expression in the gastric cancer tissues and the association of EGFR expression with clinical pathology characteristics.MethodsWe firstly analyzed the copy number alteration of EGFR gene in gastric cancer by utilizing the online TCGA resources. We then gathered 71 cases of gastric cancer patients from February 2010 to February 2015 in our hospital. The cancer tissues and normal gastric tissues were tested for EGFR expression by immunohistochemical (IHC) staining and western blotting methods. The association of EGFR expression with clinical pathology characteristics and the prognosis value of EGFR expression were evaluated by the statistical software.ResultsThe copy number of EGFR gene was found to be increased in gastric cancer patients. Western blotting confirmed that EGFR protein was obviously upregulated in tested gastric cancer tissues. Additionally, our IHC results showed that the positive rates of EGFR expression in gastric carcinoid tumors (CTs) and distant normal gastric tissues were 45.1% (32/71) and 25.0% (9/36), respectively. The former was significantly higher than the latter (P < 0.05). The EGFR-positive expression in CTs was related to tumor size, invasion depth, and lymphatic metastasis. The median survival of the EGFR-positive patients was 15.6 months, which was less than that (23.0 months) of the EGFR-negative patients [HR = 2.12, 95%CI: 1.29-4.10 (P < 0.05)]. Also, online survival analysis showed that high expression of EGFR predicted shorter overall survival of gastric cancer patients.ConclusionEGFR was highly expressed in gastric cancer tissues and associated with poor prognosis.

To determine the correlation between methylation status of 5' CpG island of cyclooxygenase-2 (COX-2) gene and protein expression in gastric cancer tissues for distinguishing the molecular characters of gastric cancers. Methylation status of 5' CpG island of COX-2 gene was studied by PCR amplification after HpaII and Hha I restrictive enzyme digestion; COX-2 expression was evaluated by immunohistochemical method. Hpa II and HhaI site were all methylated in 12 normal gastric mucosa tissues, whereas they were demethylated in 77.27% (34/44) and 84.09% (37/44) gastric cancer tissues, respectively. Expression of COX-2 was detected in 68.18% (30/44) gastric cancer tissues, but no expression was found in normal gastric mucosa tissues. In gastric cancer tissues, COX-2 expression was correlated significantly with HpaII site demethylation (29/30 vs 5/14, P<0.001 and HhaI site demethylation (28/30 vs 9/14, P<0.05). The demethylation of 5' CpG island of gene is necessary for COX-2 expression in human gastric cancer. The expression status of COX-2 may provide theoretical basis for COX-2 targeting gastric cancer treatments.

Background: Agents targeting HER2 or EGFR have been applied in several cancer types. Tumor microenvironment including tumor-infiltrating lymphocytes could be a predictive marker in HER2- or EGFR- targeted therapy, although there are some controversies. However, the effects of HER2 and EGFR inhibition on tumor microenvironment are unclear. Method: We screened HER2, EGFR, and PD-L1 expression in gastric cancer cell lines by western blot (SNU216, SNU668, SNU719, AGS, N87, YCC3, and YCC10). HER2 and EGFR was inhibited by using dual inhibitor (afatinib, lapatinib). After HER2 and EGFR inhibition, the change of PD-L1 expression was evaluated in HER2 overexpressed cell lines (SNU216, N87, SKBR3) at western blot, FACS, PCR, and qPCR. Selective blockade for down-steam molecules of HER2 and EGFR was conducted by using pictilisib (PI3K inhibitor) and trametinib (MEK inhibitor). The change of chemokines such as CXCL1, CCL2, and CCL21 was evaluated after HER2 and EGFR inhibition by PCR. In clinical data, PD-L1 expression and HER2 expression in resected gastric cancer were also evaluated by immunohistochemistry analysis. Results: EGFR-overexpressed or HER2-overexpressed gastric cancer cell lines (SNU216, SNU668, N87) showed higher protein expression of PD-L1. PD-L1 expression decreased with dose-dependent manner in afatinib- or lapatinib- treated cell lines (SNU216, N87, SKBR3). In pictilisib-treated cell lines, PD-L1 was also down-regulated. However, trametinib-treated cell lines did not show down-regulation of PD-L1. After lapatinib treatment in HER2 overexpressed cell lines, CXCL1, CCL21, and CCL2 decreased with dose-dependent manner. In 289 patients with resected gastric cancer, there was a significant association between HER2 and PD-L1 expression (p = 0.03). Conclusions: PD-L1 is associated with HER2 and EGFR expression. PD-L1 is regulated by inhibition of PI3K pathway. Therefore, HER2 or EGFR inhibition could interact with tumor microenvironment by down-regulation of expression of PD-L1 and chemokines. Citation Format: Jin Won Kim, Ji Hea Sung, Mi Hyun Kang, Ji-Won Kim, Se-Hyun Kim, Keun-Wook Lee, Hye Seung Lee, Jee Hyun Kim. HER2 or EGFR inhibition interacts with tumor microenvironment by downregulation of PD-L1 and chemokines. [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 5136.

Kita-kyushu lung cancer antigen-1 (KK-LC-1), a cancer/testis antigen (CTA), is frequently expressed in tumor and non-tumor sites of the stomach in patients with gastric cancer (GC). Additionally, KK-LC-1 has been associated with Helicobacter pylori (Hp) infection. Currently, the association between Hp eradication and GC incidence is unclear. This study aimed to investigate the association between KK-LC-1 expression and Hp eradication in GC. This study included 124 patients treated for gastric cancer. Pathological tissue from resected specimens was used to investigate KK-LC-1 expression in tumor and non-tumor sites. The association between 14 clinicopathological factors, including Hp infection and eradication, and KK-LC-1 expression was investigated and analyzed by Fisher's exact test and multivariable regression analysis. KK-LC-1 expression rate in cancerous tissues from patients with GC was 74.2%. The expression of KK-LC-1 was associated with older age, mucosal layer depth of invasion, differentiated type, no lymph node metastasis, Hp eradication, previous Hp infection, and multiple cancers. KK-LC-1 expression was high in GC cases with previous Hp infection and successful eradication. KK-LC-1 expression pattern suggests that it may be associated with GC independently of Hp infection.

This study aimed to evaluate the psychological and behavioral impacts of the coronavirus disease-2019 (COVID-19) pandemic on cancer diagnosis and staging, with particular focus on patient delays and changes in healthcare-seeking behavior before and after the onset of COVID-19. Data pertaining to 8 cancer types, including breast cancer, hepatocellular carcinoma, oral cancer, prostate cancer, gastric cancer, esophageal cancer, colon cancer, and lung cancer, sourced from the cancer registry database of Taichung Veterans General Hospital, was analyzed. The focus was on the comparisons of data between the pre-pandemic period (2017-2019) and the pandemic year (2020). Breast cancer (p < 0.001), hepatocellular carcinoma (p = 0.004), prostate cancer (p < 0.001), gastric cancer (p = 0.037), and esophageal cancer (p < 0.001) exhibited a decrease in the rate of early stage patients and an increase in the rate of advanced stage patients after the COVID-19 outbreak. Furthermore, the number of newly diagnosed patients per year decreased for hepatocellular carcinoma, oral cancer, prostate cancer, gastric cancer, esophageal cancer, colon cancer, and lung cancer. The COVID-19 pandemic disrupted cancer care, resulting in delayed diagnoses, stage migration, and a decline in newly diagnosed cases. These findings highlight the need for resilient healthcare systems to ensure continuity of cancer screening and treatment during global health crises.

Collagen XVIII is a component of vascular and epithelial basement membranes. The C-terminal fragment of the protein is termed endostatin, and is a potent inhibitor of angiogenesis. No reports on the clinical implications of collagen XVIII expression in human gastric cancer are currently available. Here, we investigate the clinical significance of collagen XVIII expression in gastric cancer. Seven gastric cancer cell lines were subjected to Western blotting. Collagen XVIII expression was examined in 118 gastric carcinoma tissues via immunohistochemistry. Western blotting revealed the presence of the 22-kDa collagen XVIII protein in four of seven gastric cancer cell lines. Immunohistochemistry detected collagen XVIII expression in the tumor cytoplasm in 115 of 118 gastric carcinoma patients (97%). No correlation was evident between collagen XVIII expression score and clinicopathologic findings when all patients were considered together. However, on subgroup analysis, 42 of 70 patients with distant metastasis were classified into low or moderate collagen XVIII expression groups, whereas the remaining 28 patients were grouped as showing high collagen XVIII expression. The prognosis for patients with high collagen XVIII-expressing gastric carcinoma was significantly worse than that for patients displaying low or moderate collagen XVIII expression (median survival time, 7.8 months vs. 18.3 months [log-rank, p = 0.01]; median time to progression, 3 months vs. 8 months [log-rank, p = 0.01]). High expression of collagen XVIII is associated with poor prognosis in patients with metastatic gastric carcinoma. Further studies on larger patient populations are warranted to validate the utility of collagen XVIII as a prognostic biomarker in gastric carcinoma.

Introduction MUC4 is overexpressed in gastric cancer and its precursor lesions and plays an essential role in disease progression. Area covered In this review, we describe the diagnostic and prognostic value of MUC4 expression in gastric cancer. First, we provide a summary of gastric cancer pathogenesis and its intricate relationship with mucin expression. We will then provide an extensive description of MUC4 expression in gastric cancer and its diagnostic and therapeutic significance. Expert opinion Apart from its protective role in normal physiology, MUC4 contributes to disease progression and metastasis in several malignancies, including gastric cancer. MUC4 is expressed at negligible levels in normal gastric mucosa. However, some patients with intestinal metaplasia and gastric cancer have high levels of MUC4 expression, particularly in the pit cell compartment. The expression of MUC4 in metaplastic pit cells is associated with increased proliferation, inflammation, and epithelial-to-mesenchymal transition. Hence, evaluating MUC4 expression in precursor lesions may help stratify disease and identify cases in which curative surgery should be performed. MUC4 expression in gastric cancer is associated with disease aggressiveness, lymphatic invasion, and nodal metastasis. Due to its role in disease pathobiology, it is a promising target for the diagnosis and therapy of gastric cancer.

Published literatures have reported the relationship between hypoxic-inducible factor-2α (HIF-2α) expression and clinicopathological features in gastric cancer (GC), but the evaluated conclusions remain controversial.A meta-analysis was carried to examine the clinicopathological features and prognostic values of HIF-2α in patients with GC. Systematic detailed searches were performed to Pub Med, Cochrane Library, and EBSCO until to August 2015.Six studies (508 specimens) were included in this meta-analysis. HIF-2α-positive expression indicates an unfavorable prognosis value and advanced clinicopathological differences for the available patient dates with GC. Further multivariate meta-analysis revealed that HIF-2α-positive expression in gastric cancer associated with deeper tumor infiltration (OR = 3.08; 95%CI: 1.18–8.04), higher rates of lymphatic metastasis (OR = 3.26; 95%CI: 1.10–9.63), higher TNM stage (III+IV) (OR = 2.61; 95%CI: 1.40–4.84), and much lower 5-year overall survival (OR = 2.08; 95%CI: 1.21–3.58). Nevertheless, there is no association between HIF-2α-positive expression and worse tumor differentiation (OR = 2.03; 95%CI: 0.73–5.64). In addition, by this subgroup analysis, HIF-2α-positive expression associated with deeper tumor infiltration (OR = 3.81; 95%CI: 1.03–14.08), higher lymphatic metastasis (OR = 4.71; 95%CI: 1.08–20.50), higher TNM stage (OR = 3.21; 95%CI: 1.57–6.57), worse tumor differentiation (OR = 3.08; 95%CI: 1.51–6.31), and lower 5-year overall survival (OR = 2.34; 95%CI: 1.15–4.79).Our results indicate that HIF-2α overexpression can potently predict the poor prognosis and may be a potential therapeutic target for gastric carcinoma, according to the limited evidence. Meanwhile, further studies are needed to elucidate the accuracy of these results.

Previously we have shown that hypoxia strongly induces the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 and -4 (PFKFB-3 and PFKFB-4) genes in several cancer cell lines via a HIF-dependent mechanism. In this paper we studied the expression and hypoxic regulation of PFKFB-4 and PFKFB-3 mRNA as well as its correlation with HIF-1alpha, HIF-2alpha, VEGF and Glut1 mRNA expression in the pancreatic cancer cell line Panc1 and two gastric cancer cell lines MKN45 and NUGC3. This study clearly demonstrated that PFKFB-3 and PFKFB-4 mRNA are expresses in MKN45, NUGC3 and Panc1 cancers cells and that both genes are responsive to hypoxia in vitro. However, their basal level of expression and hypoxia responsiveness vary in the different cells studied. Particularly, PFKFB-3 mRNA is highly expressed in MKN45 and NUGC3 cancer cells, with the highest response to hypoxia in the NUGC3 cell line. The PFKFB-4 mRNA has a variable low basal level of expression in both gastric and pancreatic cancer cell lines. However, the highest hypoxia response of PFKFB-4 mRNA is found in the pancreatic cancer cell line Panc1. The basal level of PFKFB-4 protein expression is the highest in NUGC3 gastric cancer cell line and lowest in Panc1 cells, with the highest response to hypoxia in the pancreatic cancer cell line. Further studies showed that PFKFB-3 and PFKFB-4 gene expression was highly responsive to the hypoxia mimic dimethyloxalylglycine, a specific inhibitor of HIF-alpha hydroxylase enzymes, suggesting that the hypoxia responsiveness of PFKFB-3 and PFKFB-4 genes in these cell lines is regulated by the HIF transcription complex. The expression of VEGF and Glut1, which are known HIF-dependent genes, is also strongly induced under hypoxic conditions in gastric and pancreatic cancer cell lines. The levels of HIF-1alpha protein are increased in both gastric and pancreatic cancer cell lines under hypoxic conditions. However, the basal level of HIF-1alpha as well as HIF-2alpha mRNA expression and their hypoxia responsiveness are different in the MKN45 and NUGC3 cancer cells. Thus, the expression of HIF-1alpha mRNA is decreased in both gastric cancer cell lines treated by hypoxia or dimethyloxalylglycine, but HIF-2alpha mRNA expression is not changed significantly in NUGC3 and slightly increased in MKN45 cells. Expression of PFKFB-4 and PFKFB-3 was also studied in gastric cancers and corresponding nonmalignant tissue counterparts from the same patients on both the mRNA and protein levels. The expression of PFKFB-3 and PFKFB-4 mRNA as well as PFKFB-1 and PFKFB-2 mRNA was observed in normal human gastric tissue and was increased in malignant gastric tumors. The basal level of PFKFB-4 protein expression in gastric cancers was much higher as compared to the PFKFB-3 isoenzyme. In conclusion, this study provides evidence that PFKFB-4 and PFKFB-3 genes are also expressed in gastric and pancreatic cancer cells, they strongly respond to hypoxia via a HIF-1alpha dependent mechanism and, together with the expression of PFKFB-1 and PFKFB-2 genes, possibly have a significant role in the Warburg effect which is found in malignant cells.

Objective:To analyze the expression and clinical significance of retinoic acid-induced protein 14 (RAI14) in gastric cancer and its relationship with immune cell infiltration by mining databases such as Oncomine, TIMER, UALCAN, and Kaplan Meier Plotter.Methods:RAI14 expression in various cancer types was analyzed using the Oncomine and TIMER databases. We used the Kaplan-Meier Plotter and UALCAN databases to evaluate the impact of RAI14 on clinicopathological parameters in gastric cancer. The correlation between RAI14 expression and immune cell invasion was studied using TIMER. TIMER was also used to analyze the correlation between RAI14 expression and marker levels of tumor-infiltrating immune cells.Results:High RAI14 expression in gastric cancer was significantly associated with poor overall survival (OS; hazard ratio [HR] = 1.82, 95% confidence interval [CI] = 1.53–2.15, P < 0.001) and poor progression-free survival (PFS; HR = 2.16, 95% CI = 1.77–2.65, P < 0.001). Furthermore, high RAI14 expression was significantly associated with poor prognosis of patients with stage 2–4 gastric cancer, but not with OS and PFS of stage 1 patients (OS P = 0.17; PFS P = 0.09), and patients with stage N0 PFS had nothing to do (PFS P = 0.238). RAI14 expression was positively correlated with the infiltration levels of monocytes, tumor-associated macrophages, macrophages, neutrophils, and Treg cells in gastric cancer. Besides, RAI14 expression was closely related to various marker genes in immune cells.Conclusion:RAI14 is highly expressed in gastric cancer, and its expression level is correlated with the prognosis of patients with gastric cancer. RAI14 plays also an important role in the recruitment and regulation of infiltrating immune cells and is, thus, expected to become a target for the optimal treatment of gastric cancer.

The enhancer of zeste homolog 2 (EZH2), a member of the polycomb group of proteins, plays an important role in cell proliferation and cell cycle regulation. EZH2 is overexpressed in aggressive forms of prostate, breast, bladder, and endometrial cancers. However, the role of EZH2 expression in gastric cancer has not been fully determined. This study was conducted to investigate the correlation between EZH2 and cell cycle-related molecules, and the clinical value of EZH2 expression in gastric cancer. We analyzed EZH2 expression using Western blotting in AGS, MKN-28, SNU-16, SNU-484, SNU-601, and SNU-638 gastric cancer cell lines. After transfection of EZH2 siRNA into MKN-28 cells, the change in cell cycle-related molecules was assessed by Western blot analysis. Expression of EZH2, Ki-67, and p53 was determined by immunohistochemical staining of tissue microarrays from specimens of 137 cases of resected gastric cancer. We found high expressions of EZH2 in all of the tested gastric cancer cell lines. RNA interference of EZH2 induced upregulation of p53 and HDAC1 and downregulation of cyclin D1 and cyclin E. High EZH2 expression was observed in 60.6% of gastric cancers and in 6.7% of non-neoplastic gastric tissues (p < 0.01); 40.1% were positive for p53 in gastric cancers. High EZH2 expression was correlated with Ki-67 and p53 expressions and was significantly associated with distant metastases and non-signet ring cells. Our results suggest that high EZH2 expression is associated with tumor cell proliferation and metastasis in gastric cancer.

ObjectivesKH-type splicing regulatory protein (KHSRP) is an RNA-binding protein involved in several cellular processes, including nuclear splicing, mRNA localization, and cytoplasmic degradation. While KHSRP’s role has been studied in other cancers, its specific involvement in gastric cancer remains poorly understood. This study aims to explore KHSRP expression in gastric cancer and its potential effects on tumor progression and immune response. MethodsKHSRP expression in gastric cancer tissues and normal tissues was analyzed using data from The Cancer Genome Atlas (TCGA) database. The correlation between KHSRP expression, patient survival, and immune response was also assessed. Immunohistochemistry was performed to evaluate KHSRP expression in gastric cancer tissues. Gain- and loss-of-function experiments were conducted to assess KHSRP’s effects on gastric cancer cell proliferation, stemness, and migration. Furthermore, the impact of KHSRP silencing on tumor volume and immune cell infiltration was evaluated in a C3H/He mouse xenograft model. ResultsKHSRP was found to be overexpressed in gastric cancer tissues compared to normal tissues, with a positive correlation to tumor stage and a negative correlation with patient prognosis. Functional assays revealed that KHSRP promotes gastric cancer cell proliferation, enhances cancer stem cell properties, and increases migratory capabilities in vitro. In vivo, KHSRP silencing led to a significant reduction in tumor volume and increased immune cell infiltration in the mouse xenograft model.ConclusionsKHSRP acts as an oncogene in gastric cancer by promoting tumorigenesis and suppressing anti-tumor immune responses. Its overexpression is associated with poor prognosis, making KHSRP a potential prognostic marker and therapeutic target in gastric cancer.

microRNA (miR)-22 has been reported to be downregulated in hepatocellular, lung, colorectal, ovarian and breast cancer, acting as a tumor suppressor. The present study investigated the potential effects of miR-22 on gastric cancer invasion and metastasis and the molecular mechanism. miR-22 expression was examined in tumor tissues of in 89 gastric cancer patients by in situ hybridization (ISH) analysis. Additionally, the association between miR-22 levels and clinicopathological parameters was analyzed. A luciferase assay was conducted for target identification. The ability of invasion and metastasis of gastric cancer cells in vitro and in vivo was evaluated by cell migration and invasion assays and in a xenograft model. The results showed that miR-22 was downregulated in the gastric cancer specimens and significantly correlated with the advanced clinical stage and lymph node metastasis. In addition, metadherin (MTDH) was shown to be a direct target of miR-22 and the expression of MTDH was inversely correlated with miR-22 expression in gastric cancer. Ectopic expression of miR-22 suppressed cell invasion and metastasis in vitro and in vivo. The present study suggested that miR-22 may be a valuable prognostic factor in gastric cancer. miR-22 inhibited gastric cancer cell invasion and metastasis by directly targeting MTDH. The novel miR-22/MTDH link confirmed in the present study provided a novel, potential therapeutic target for the treatment of gastric cancer.

Is human kallikrein-11 in gastric cancer treated with surgery and adjuvant chemoradiotherapy associated with survival?

The S100A2 gene has been reported to be a putative tumor‑suppressor gene. Nevertheless, overexpression of S100A2 has been found in certain types of cancer. This study investigated S100A2 expression in tissue specimens of gastritis, intestinal metaplasia, adenomatous dysplasia and gastric cancer to determine its association with clinical features. A serial of tissue samples (gastritis, intestinal metaplasia, adenomatous dysplasia and gastric cancer samples) were used for quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), western blotting and immunohistochemical analyses of S100A2 expression. The data revealed that there was a gradual loss of S100A2 expression from gastritis, intestinal metaplasia and dysplasia to cancer tissue specimens (p<0.001). In gastric cancer samples, loss of S100A2 expression was associated with increased tumor size, depth of invasion, lymph node metastasis and a poor prognosis (p<0.001). However, the intestinal type of gastric cancer expressed more S100A2 protein than the diffuse type (p<0.001). In conclusion, data from the present study demonstrated that loss of S100A2 expression contributes to gastric cancer development and progression; therefore, the determination of S100A2 expression levels may help to predict the carcinogenesis and aggressiveness of gastric cancer as well as patient survival.