Overexpression In Gastric Cancer Research Articles

EIF2S2 transcriptionally upregulates HIF1α to promote gastric cancer progression via activating PI3K/AKT/mTOR pathway.

Eukaryotic translation initiation factor 2 subunit beta (EIF2S2) is a protein that controls protein synthesis under various stress conditions and is abnormally expressed in several cancers. However, there is limited insight regarding the expression and molecular role of EIF2S2 in gastric cancer. In this study, we identified the overexpression of EIF2S2 in gastric cancer by immunohistochemical (IHC) staining and found a positive correlation between EIF2S2 expression and shorter overall survival and disease-free survival. Functionally, we revealed that EIF2S2 knockdown suppressed gastric cancer cell proliferation and migration, induced cell apoptosis, and caused G2 phase cell arrest. Additionally, EIF2S2 is essential for in vivo tumor formation. Mechanistically, we demonstrated that EIF2S2 transcriptionally regulated hypoxia induicible factor-1 alpha (HIF1α) expression by NRF1. The promoting role of EIF2S2 in malignant behaviors of gastric cancer cells depended on HIF1α expression. Furthermore, the PI3K/AKT/mTOR signaling was activated upon EIF2S2 overexpression in gastric cancer. Collectively, EIF2S2 exacerbates gastric cancer progression via targeting HIF1α, providing a fundamental basis for considering EIF2S2 as a potential therapeutic target for gastric cancer patients.

The role of determining HER2neu status in patients with gastric cancer.

e16067 Background: Over the past two decades, gastric cancer has continued to maintain a leading position in both incidence and mortality rates among all malignant neoplasms in the Republic of Kazakhstan. Recent data indicate that amplification or overexpression of the HER2 gene is detected in 7-34% of gastric cancer cases, significantly impacting treatment outcomes. Studying a specific group of patients with HER2 overexpression in gastric cancer is of great interest in clinical oncology. Research aim: To examine the long-term treatment outcomes in patients with gastric cancer depending on the status and level of HER-2 expression in real clinical practice. Methods: Analysis was conducted on 172 formalin-fixed paraffin-embedded samples of gastric adenocarcinoma and gastroesophageal junction carcinoma, subjected to immunohistochemical examination to determine HER2 protein expression. Patients' ages ranged from 18 to 85 years, with a mean age of 61.7 years; among them, 106 (61.6%) were male and 66 (38.4%) were female. Of the 172 patients, 64 (37.2%) had primary tumors located at the gastroesophageal junction, while 108 (62.8%) had tumors located in the body of the stomach. Based on differentiation grade, the majority were G3-100 (50%), G2-91 (45%), G1-9 (5%). HER2 testing was performed on the Ventana BenchMark Ultra platform using the HER2 (4B5) antibody. Results: HER2 overexpression was detected in 26 (15.1%) of the 172 patients. Patients with HER2 2+ non-amplified were 6 (3.5%), HER2 2+ amplified were 8 (4.6%), HER2 1+ was detected in 19 (11%) cases, and HER2 0 was found in 121 (80.9%) cases. Long-term results revealed statistically significant differences, notably the highest overall survival rate in patients with HER-2 overexpression compared to HER-2 low and absence of HER-2. The HER2 3 (+FISH/SISH) variant was significantly more prevalent in 84.6% compared to HER2 0 in 52%, and HER2 1 in 48%, p < 0.05. Comparison of Her2 status using the chi-square method in groups revealed probable differences concerning tumor localization, with a criterion value of 0.034; morphological form (criterion value = 5.83); and differentiation grade (criterion value = 10.05). Conclusions: These results underscore the importance of further HER2 research in gastric cancer and gastroesophageal junction carcinoma for the development of personalized therapeutic strategies.

Clinicopathologic features and prognosis of HER2- positive gastric cancer

Abstract Background The role of human epidermal growth factor receptor 2 (HER2) overexpression has been well established in breast cancer, with corresponding targeted therapies. In contrast, the clinicopathological features and prognosis of HER2 overexpression in gastric cancer remain inconclusive. Methods In this study, 334 patients with gastric cancer who received surgical resection between May 2017 and June 2021 were enrolled at a single medical center in Taiwan. HER2 status was determined by immunohistochemistry (IHC) staining or fluorescence in situ hybridization (FISH). The clinicopathological features and survival curves of the HER2-positive and HER2-negative gastric cancer patients were analyzed. Results The HER2-positive ratio was 7.2%. HER2-positive gastric cancer was associated with more differentiated tumors (P=0.016), more Lauren’s intestinal type (P=0.010) and a higher portion of Ming’s expanding type (P=0.033) in the univariate analysis, but only Lauren’s intestinal type was an independent factor in the logistic regression model (P=0.015). The overall survival and disease-free survival between the HER2-positive and HER2-negative groups were not significantly different. Patients with HER2-positive gastric cancer were more likely to have distant lymphatic recurrence than those with HER2-negative gastric cancer (P=0.026). Conclusions HER2-positive gastric cancer is associated with intestinal histological type and distant lymphatic recurrence, but HER2 is not an independent prognostic factor.

Abstract 5583: Helicobacter pylori induces the wee1, promoting immune suppressive in human gastric adenocarcinoma

Abstract Background: Gastric cancer (GC) is the fourth most common cause of cancer-related death worldwide. GC has a dismal 5-year survival rate of about 32%. Helicobacter pylori (H. pylori) infection is the strongest risk factor for gastric carcinogenesis. 75-90% of gastric cancer patients exhibit positive H. pylori serology. WEE1 is a nuclear kinase that regulates cell cycle progression by inhibiting cyclin-dependent kinases. Methods & Results: Analysis of non-cancer normal stomach tissue (n=360) and human GC samples (n=1221) identified that WEE1 mRNA was significantly overexpressed in GC. Using immunohistochemistry (IHC) staining in 41 normal and 44 GC human samples, the data indicated that WEE1 protein was significantly overexpressed in GC. Western blot and immunofluorescence (IF) staining confirmed that H. pylori infection induces WEE1 overexpression in GC cells with an unexpected cytosolic localization of WEE1 in GC cells. Tff1 knockout GC mouse model (Tff1-/-) was infected with mouse-adapted H. pylori strain PMSS1. Western blot and immunohistochemistry data demonstrated that H. pylori infection induced WEE1 expression in Tff1 -/- HGD/cancer mouse gastric tissues compared to control Tff1 -/- mouse stomach. To study how H. pylori infection induces WEE1 in GC, analysis from miRTAR, Target Scan, and miRDB demonstrated that WEE1 is predicted to be targeted by miR-497-5p. Using qRT-PCR analysis, we assessed 30 normal and 30 GC human tissue samples, revealing a pronounced downregulation of miR-497-5p in GC specimens. Western blot analysis confirmed that the restoration of miR-497-5p in GC cells markedly reduced WEE1 protein expression. Interestingly, H. pylori infection further decreased miR-497-5p levels in GC cells, upregulating WEE1 protein expression. Since the miR-497-5P host gene promoter region contains CpG islands, we confirmed that treatment with 5 Azacytidine (demethylating agent) or DNMT1 knockdown induced expression of miR-497-5p with decreased WEE1 level in GC cells. Furthermore, our preliminary results indicate that aberrant WEE1 overexpression in GC demonstrates a significant positive correlation with immune-suppression gene signatures, underscoring its predictive value for unfavorable patient survival outcomes in GC. Using the TFF1 knockout mouse GC model, we found that WEE1 inhibition notably decreases the number and activation of CD4+ and CD8+ T cells in neoplastic gastric tissues. These findings also indicate a crucial relationship between WEE1 and the immunosuppressive microenvironment in GC, establishing WEE1 as a promising therapeutic target to enhance therapeutic efficacy and overcome immunotherapy resistance in GC. Conclusions: Our findings demonstrated a novel mechanism in which H. pylori activates the WEE1 in GC, promoting an immune suppressive microenvironment. WEE1 inhibition with immunotherapy could be a promising therapeutic method for GC patients. Citation Format: Md Obaidul Islam, Krishnapriya Thangaretnam, Heng Lu, Dunfa Peng, Nadeem Sidiq Bhat, Mohammed Soutto, Wael El-Rifai, Zheng Chen. Helicobacter pylori induces the wee1, promoting immune suppressive in human gastric adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5583.

Prediction and therapeutic targeting of the tumor microenvironment-associated gene CTSK in gastric cancer

BackgroundCathepsin-K (CTSK) is overexpressed in Gastric cancer (GC) and the mechanism of its overexpression in GC is still unclear. The present work found CTSK as a potential predictive biomarker and immunotherapeutic target for GC based on the tumor microenvironment (TME).MethodsFrom public databases, gene expression profiles and clinical data of GC were downloaded to analyze the distribution of stromal and immune cells and tumor abundance in TME. Differentially expressed genes (DEGs) associated with TME were obtained by differential analysis, followed by cross-screening to obtain CTSK as a gene associated with TME. Next, a series of methods and tools were employed to explore the relationships between clinicopathological features of GC and CTSK expression as well as prognosis, tumor immune microenvironment, immune checkpoints and drug sensitivity. And GSEA was used to investigate the potential role of CTSK in the tumor microenvironment of GC.ResultsFrom the dataset, we obtained a total of 656 DEGs associated with TME and the stromal component of TME was found to be closely involved in GC prognosis. CTSK was cross-screened as the key gene associated with TME by the PPI network and univariate Cox regression analysis. Pan-cancer analysis revealed significant high expression of CTSK in a variety of cancers. Subsequently, we hypothesized that high-expressed CTSK was closely correlated with poor prognosis and lymph node metastasis of tumors, and that CTSK, a GC TME-related gene, was largely involved in a range of biological behaviors of tumors, with a significant correlation between several immune cells.ConclusionCTSK was validated as a potential prognostic biomarker related to TME of GC and could be a promising next-generation immunotherapeutic target for GC.

Pilot study of HER2 targeted 64 Cu-DOTA-tagged PET imaging in gastric cancer patients.

Human epidermal growth factor receptor 2 (HER2) is an important biomarker for targeted gastric cancer (GC) immunotherapy. However, heterogeneous HER2 overexpression in GC, loss of HER2 expression during therapy, and inability to non-invasively identify HER2 overexpressing tumors impede effective targeting therapies. Improved HER2-specific functional imaging can address these challenges. Trastuzumab is a HER2-directed mAb to treat HER2 overexpressing cancers. The 64 Cu-DOTA-trastuzumab radiotracer is used to detect HER2+ metastatic breast cancer. We aimed to develop 64 Cu-DOTA-trastuzumab PET-CT to detect and characterize tumor uptake in HER2+ or - GC patients. We conducted a single-arm phase II pilot study exploring the feasibility of 64 Cu-DOTA-trastuzumab for PET imaging of HER2 overexpressing GC compared to HER2 non-expressing tumors. Eight patients with biopsy-confirmed gastric adenocarcinoma were included. Immunohistochemistry was used to evaluate primary tumor biopsies for HER2 overexpression. Patients were injected with 45 mg of cold trastuzumab followed by 5 mg of 64 Cu-DOTA-trastuzumab. PET-CT scans were performed 24-48 h post radiotracer injection and compared to standard staging CT scans. We observed limited toxicity following 64 Cu-DOTA-trastuzumab injections. While there was uptake of the radiotracer in portions of HER2+ lesions, there was no statistically significant distinction between tumor and background by standardized uptake value analysis. Despite the potential of 64 Cu-DOTA-trastuzumab PET imaging of HER2+ metastatic breast cancer, a 5 mg dose of this radiotracer injected 24-48 h before imaging was insufficient to identify HER2+ GC. These results inform future GC imaging studies to optimize biomarker-targeted therapies based on dosage and timing for more clinically relevant imaging.

MCM4 expression is associated with high-grade histology, tumor progression and poor prognosis in urothelial carcinoma

BackgroundWe previously reported Minichromosome maintenance 4 (MCM4) overexpression in gastric cancer. However, the clinicopathological significance of MCM4 in urothelial carcinoma (UC) has not been investigated. To clarify the clinicopathological significance of MCM4 in UC, we investigated MCM4 expression with immunohistochemistry (IHC).MethodsWe analyzed the expression and distribution of MCM4 in 124 upper tract urothelial carcinoma (UTUC) samples by IHC. Additionally, using 108 urine samples, we analyzed MCM4 Immunocytochemistry (ICC) expression in urine cytology.ResultsIn normal urothelium, MCM4 expression was weak or absent. Meanwhile, the strong nuclear expression of MCM4 was observed in UTUC tissues, and it was detected in 77 (62%) of a total of 124 UTUC cases. MCM4-positive UTUC cases were associated with nodular/flat morphology, high grade, high T stage, and poor prognosis. Moreover, MCM4 expression was significantly higher in the invasive front than in the tumor surface. Similar results were also obtained in TCGA bladder cancer cohort. Additionally, MCM4 expression was associated with high expression of Ki-67, HER2, EGFR, and p53 in UTUC. Among representative cancer-related molecules, MCM4 had an independent predictive value for progression-free survival and high-grade UC. ICC for MCM4 was also performed on urine cytology slides and showed that the nuclear expression of MCM4 was more frequently found in UC cells than in non-neoplastic cells. The diagnostic accuracy of urine cytology was improved by combining MCM4 immunostaining with cytology.ConclusionThese results suggest that MCM4 might be a useful predictive biomarker for high-grade histology, tumor progression and poor prognosis in UC. Moreover, ICC for MCM4 might be helpful for UC detection as additional markers in the cytomorphology-based diagnosis.

Serine protease PRSS56, a novel cancer-testis antigen activated by DNA hypomethylation, promotes colorectal and gastric cancer progression via PI3K/AKT axis

BackgroundCancer/testis (CT) antigens/genes are usually overexpressed in cancers and exhibit high immunogenicity, making them promising targets for immunotherapy and cancer vaccines. The role of serine protease PRSS56 in cancers remains unknown to date.MethodsRNA sequencing studies were performed to screen CT genes in gastric cancer (GC) and colorectal cancer (CRC) cells exposed to DNA methyltransferase inhibitor 5-aza-2’-deoxycytidine (5-AZA-CdR). Bioinformatics analysis was conducted to analyze the correlation between PRSS56 expression and DNA methylation. Functional experiments were performed to explore the biological function of PRSS56 in GC and CRC.ResultsIn this study, we identified the testis-specific serine proteases PRSS56 as a novel CT antigen. PRSS56 was frequently overexpressed in various cancers, especially in gastrointestinal cancer. PRSS56 expression was negatively associated with promoter DNA methylation level, and positively associated with gene body methylation level. PRSS56 expression was significantly activated in colorectal and gastric cancer cells exposed to DNA methyltransferase inhibitors. Importantly, our finding highlights that the decreased methylation level of the CpG site cg10242318 in the PRSS56 promoter region resulted in its overexpression in GC and CRC. Additionally, functional assays verified that PRSS56 overexpression activated PI3K-AKT signaling in GC and CRC.ConclusionSerine protease PRSS56 is a novel CT antigen that is reactivated in cancers by promoter DNA hypomethylation. PRSS56 functions oncogenic roles in GC and CRC by activating of PI3K/AKT axis. Our results presented here represent the first data on the function of the serine protease PRSS56 in cancers.

GASTric Cancer HER2 Re-Assessment Study 2 (GASTHER2): HER2 Re-assessment for Initially HER2-Negative Advanced Gastric Cancer Patients after Progression on First-Line Treatment.

Heterogeneous human epidermal growth factor receptor 2 (HER2) overexpression in gastric cancer may lead to a misdiagnosis of HER2 status. Accurate assessment of HER2 status is essential for optimal treatment as novel HER2-directed agents are being investigated in various clinical settings. We evaluated the usefulness of HER2 re-assessment following progression on first-line treatment in initially HER2-negative advanced gastric cancer (AGC) patients. We enrolled 177 patients with baseline HER2-negative AGC and performed HER2 re-assessment after progression on first-line treatment from February 2012 to June 2016 at Asan Medical Center, Seoul, Korea. The re-assessed HER2 status was analyzed with baseline HER2 status and clinical characteristics. The median age was 54 years (range, 24 to 80 years), and 123 patients (69.5%) were men. Seven patients (4.0%) were HER2-positive on the re-assessment. Patients with baseline HER2 negativity confirmed by a single test (n=100) had a higher HER2-positive re-assessment rate compared to those who had repeated baseline testing (n=77) (5.0% vs. 2.6%). Among the patients with single baseline HER2 testing, the rate was higher in patients with baseline HER2 immunohistochemistry (IHC) 1+ compared to those with IHC 0 (13.4% vs. 3.6%). Overall, 4.0% of patients with baseline HER2-negative AGC were HER2-positive on re-assessment, and the HER2-positive re-assessment rate was higher among patients who had a single test at baseline. HER2 re assessment may be considered for initially HER2-negative patients to determine their eligibility for HER2-directed therapy, particularly if their HER2 negativity was determined by a single test, especially if they had a single baseline HER2 IHC 1+ test.

Overexpression of Copines-1 is associated with clinicopathological parameters and poor outcome in gastric cancer.

Copines-1 (CPNE1) is a soluble membrane-binding protein that includes two tandem C2 domains at the N-terminus and a C terminal A domain. Importantly, it is associated with the prognosis of various tumors, but there are only a few studies regarding the role of CPNE1 in gastric cancer (GC). This study aimed to explore the clinicopathological significance and prognostic potential of CPNE1 expression in GC. Data from the TIMER2.0 and UALCAN were analyzed to assess CPNE1 mRNA levels in GC. The prognostic role of CPNE1 mRNA was examined via the Kaplan-Meier plotter. CPNE1 protein expression in tumor tissues was analyzed via immunohistochemistry of clinical samples from 99 GC patients. The relationship of CPNE1 expression with clinicopathological parameters and overall survival (OS) was evaluated using Cox proportional hazards regression models and Kaplan-Meier survival curves. Copines-1 mRNA levels were higher in GC tissues than in adjacent normal tissue (ANT) (p< 0.05). Further, high CPNE1 mRNA expression indicated poor OS (p= 9.4 e-10) and was significantly associated with first progression (FP) (p= 1.6 e-06) and post-progression survival (PPS) (p= 1.5 e-12). In addition, CPNE1 protein expression was higher in GC tissues than in ANT (p< 0.0001). Moreover, CPNE1 high expression was significantly related to advanced tumor-node-metastasis (TNM) stage (p= 0.004), lymph node metastasis (p= 0.003), and vascular invasion (p= 0.001). Kaplan-Meier analysis showed that GC patients with high expression CPNE1 group had worse OS than low expression group (p= 0.003). Univariate analysis showed that age (hazard ratio [HR]=1.992; 95% confidence interval [CI], 1.009-3.934; p= 0.047), advanced TNM stage (HR=4.941; 95% CI, 2.052-11.897; p= 0.000), tumor invasion (HR=3.472; 95% CI, 1.349-8.937; p= 0.010), lymph node metastasis (HR=8.846; 95% CI, 2.708-28.897; p= 0.000), vascular invasion (HR=3.237; 95% CI, 1.521-6.891; p= 0.002), nervous invasion (HR=2.324; 95% CI, 1.205-4.479; p= 0.012), and CPNE1 expression (HR=3.464; 95% CI, 1.440-8.334; p= 0.006) were correlated with OS. In the multivariate analysis, age (HR=2.514; 95% CI, 1.264-4.999; p= 0.009), lymph node metastasis (HR=8.441; 95% CI, 2.553-27.906; p< 0.05), and CPNE1 expression (HR=2.549; 95% CI, 1.051-6.186; p= 0.039) were significant prognostic predictors for GC. Copines-1 overexpression in GC is significantly associated with poor prognosis. Thus, CPNE1 levels may serve as a prognostic biomarker in GC patients.

Phosphoglycerate mutase 1 that is essential for glycolysis may act as a novel metabolic target for predicating poor prognosis for patients with gastric cancer.

To identify a novel marker for gastric cancer, we examined the usefulness of phosphoglycerate mutase 1 (PGAM1) as a potential diagnostic marker using isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics and evaluated its clinical significance. Proteins from a discovery group of four paired gastric cancer tissues and adjacent gastric tissues were labeled with iTRAQ reagents and then identified and quantified using LC-MS/MS. The expression of PGAM1 was further validated in 139 gastric cancer patients using immunohistochemistry. Furthermore, the correlation of PGAM1 expression with clinical parameters was analyzed. Gene set enrichment analysis (GSEA) was performed to identify gene sets that were activated in PGAM1-overexpressing patients with gastric cancer. PGAM1 was significantly overexpressed in most cancers but particularly so in gastric cancer, with a sensitivity of 82.01% (95% confidence interval [CI]: 75.5%-88.5%) and specificity of 79.13% (95% CI: 72.3%-86%). Its expression was significantly associated with histological grade II and III tumors (p=0.033), lymph node metastasis (p=0.031), and TNM III-IV staging (p=0.025). The area under the receiver operating characteristic (ROC) curve for the detection of PGAM1 overexpression in gastric cancer was 0.718 (p < 0.01). Furthermore, GSEA revealed that several important pathways such as glycolysis pathway and immune pathways were significantly enriched in patients with gastric cancer with PGAM1 overexpression. This study provided a sensitive method for detecting PGAM1, which may serve as a novel indicator for poor prognosis of gastric cancer, as well as a potent drug target for gastric cancer.

Epigenetic modification facilitates proline synthase PYCR1 aberrant expression in gastric cancer

Background & aimsPyrroline-5-carboxylate reductase 1 (PYCR1) upregulation contributes to the progression of gastric cancer (GC) and indicates poor survival. However, PYCR1 expression profile in GC subtypes and the mechanism behind its upregulation are not well-studied. MethodsPYCR1 expression profiles in GC subtypes and different stages of gastric carcinogenesis were assessed in different GC cohorts. Genetic alterations and epigenetic modulation in PYCR1 regulation were further investigated using bioinformatics analysis and in vitro experiments. ResultsPYCR1 expression was significantly higher in intestinal-type GC and associated molecular subtypes in TCGA and ACRG GC cohorts. During the cascade of intestinal-type GC, PYCR1 was continuously increased from normal gastric tissues through to atrophic gastritis, to intraepithelial neoplasia, and to GC. Copy number alterations in PYCR1 were associated with PYCR1 transcript expression. One CpG island was observed in PYCR1 promoter region, and the hypomethylation occurred at this region could contribute to PYCR1 transcriptional activation in GC. Besides, H3K27ac combination was found in PYCR1 promoter, and acetyltransferase p300 induced H3K27ac could promote PYCR1 expression in GC. ConclusionsPYCR1 expression varies across GC subtypes, with intestinal-type GC and associated molecular subtypes having the highest expression. Hypomethylation at CpG sites and p300-induced H3K27ac modification within PYCR1 promoter could contribute to maintaining PYCR1 overexpression in GC. These results provide us with a new insight into epigenetic modulation in mitochondrial proline metabolism.

Overexpression of Tetraspanin31 contributes to malignant potential and poor outcomes in gastric cancer.

Tetraspanin has important functions in many cancers by aggregating with various proteins that interact with intracellular signaling proteins. The molecular function of Tetraspanin31 (TSPAN31), located in the 12q14 amplified region in various cancers, remains unclear in gastric cancer (GC). We tested whether TSPAN31 acts as a cancer‐promoting gene through its activation or overexpression in GC. We analyzed seven GC cell lines and 189 primary tumors, which were curatively resected in our hospital between 2011 and 2013. Overexpression of the TSPAN31 protein was frequently detected in three GC cell lines (42.9%) and 62 primary GC specimens (32.8%). Overexpression of TSPAN31 was significantly correlated with lymphatic invasion, venous invasion, more advanced pT and pN stages, and a higher recurrence rate. Moreover, TSPAN31 positivity was an independent factor predicting worse patient outcomes (p = 0.0283, hazard ratio 3.97). Ectopic overexpression of TSPAN31 facilitated cell proliferation of GC cells, and knockdown of TSPAN31 inhibited cell proliferation, migration, invasion, and epithelial–mesenchymal transition of GC cells through the PI3K‐Akt pathway and increased cell apoptosis in a TP53 mutation‐independent manner. In vivo analysis also revealed knockdown of TSPAN31 suppressed tumor progression. In addition, knockdown of TSPAN31 improved chemosensitivity to cisplatin through the suppression of ABCC2. These findings suggest that TSPAN31 plays a crucial role in tumor‐malignant potential through overexpression, highlighting its utility as a prognostic factor and a potential therapeutic target in GC.

Targeting kinesin family member 21B by miR-132-3p represses cell proliferation, migration and invasion in gastric cancer

ABSTRACT Recently, kinesin family member 21B (KIF21B) has been reported to be an oncogene in non-small cell lung cancer and hepatocellular carcinoma. However, the functional role of KIF21B and related molecular mechanisms in gastric cancer (GC) remain largely uncovered. In this study, online bioinformatics analysis showed that KIF21B was overexpression in GC and predicted poor prognosis. Consistently, we found that the protein expression of KIF21B was upregulated in GC tissues compared with adjacent tissues by immunohistochemistry. Knockdown of KIF21B significantly suppressed cell proliferation, migration and invasion in GC cell lines (AGS and SNU-5) using Cell counting kit‑8 (CCK-8) assay, colony formation and transwell assay. KIF21B was confirmed as the target of miR-132-3p in GC cells by luciferase reporter assay. Moreover, miR-132-3p was down-regulated and KIF21B expression was upregulated in GC tissues. Overexpression of KIF21B reversed the miR-132-3p-mediated suppressive effects on GC cell proliferation, migration and invasion. Furthermore, miR-132-3p overexpression downregulated the protein levels of Wnt1, c-Myc, β-catenin, proliferating cell nuclear antigen (PCNA) and N-cadherin, and upregulated E-cadherin expression in GC cells, which were all alleviated after KIF21B overexpression. In conclusion, our findings indicate that down-regulation of KIF21B by miR-132-3p suppresses cellular functions in GC, which might be linked to reduced Wnt/β-catenin signaling.

TWIST1-EP300 Expedites Gastric Cancer Cell Resistance to Apatinib by Activating the Expression of COL1A2.

The association between collagen type I alpha (COL1A) and chemoresistance has been verified in cancers. However, the specific role of COL1A2 in gastric cancer (GC) cell resistance to apatinib, a highly selective small-molecule inhibitor of vascular endothelial growth factor receptor 2, has not been investigated before. The purpose of this study was to explore the potential factors associated with COL1A2 regulation on GC cell apatinib resistance in vitro. With the aid of the Oncomine database and integrated bioinformatics methods, we identified COL1A2 overexpression in GC and its prognostic value. Mechanistically, the COL1A2 promoter has a distinct H3K27ac modification site and that E1A binding protein p300 (EP300) and twist family bHLH transcription factor 1 (TWIST1) can bind to the COL1A2 promoter, which in turn transcriptionally activated COL1A2 expression. In addition, overexpression of COL1A2 significantly promoted resistance to apatinib in GC cells, but knockdown of EP300 or TWIST1 remarkably inhibited COL1A2 expression and promoted sensitivity of GC cells to apatinib. Our findings demonstrated that the combination of EP300 and TWIST1 has a synergistically regulatory effect on COL1A2 expression, thus contributing to apatinib resistance in GC cells.

LncRNA/miR-29c-Mediated High Expression of LOX Can Influence the Immune Status and Chemosensitivity and Can Forecast the Poor Prognosis of Gastric Cancer.

Gastric carcinoma is the fourth most prevalent cause of cancer-related deaths worldwide because of dismal prognosis and few therapeutic options. Accumulated studies have indicated that targeting lysyl oxidase (LOX) family members may serve as an anticancer strategy. Nevertheless, the specific mechanisms of LOX in stomach carcinoma are still unclear. In this study, we demonstrated that LOX is significantly different in 13 types of cancers and may act as a potential therapeutic target, especially in stomach carcinoma. Moreover, overexpression of LOX in gastric carcinoma was validated by multiple databases and contributed to the poor overall survival (OS), progression-free survival (PFS) and post-progression survival (PPS) of stomach adenocarcinoma (STAD) patients. Next, based on the ceRNA hypothesis, the HIF1A-AS2/RP11-366L20.2-miR-29c axis was characterized as the upstream regulatory mechanism of LOX gene overexpression in gastric cancer by combining correlation analysis, expression analysis, and survival analysis. Finally, we illustrated that LOX gene overexpression leads to dismal prognosis of gastric cancer, perhaps through promoting M2 macrophage polarization and tumor immune escape and enhancing drug resistance of tumor cells to chemotherapeutic drugs. Our research demonstrate that LOX may be potentially applied as a novel prognostic marker and targeting inhibition of LOX holds promise as a treatment strategy for gastric cancer.

RNF114 Silencing Inhibits the Proliferation and Metastasis of Gastric Cancer.

RNF114 (E3 ubiquitin ligase RING finger protein 114) was first identified as a zinc-binding protein that promotes psoriasis development; however, its role in gastric cancer is still unclear. We explored the relationship between RNF114 and gastric cancer using bioinformatics and molecular biology techniques. The results showed that RNF114 was highly expressed in gastric cancer and negatively correlated with the patient's prognosis. Functional assays suggested that RNF114 silencing suppressed the proliferation and metastasis of gastric cancer cells to a certain extent. Further studies showed that RNF114 expression was potentially targeted by miR-218-5p and methylation modification, and mediated downstream EGR1 (early growth response 1) degradation by the ubiquitylation approach. Together, the present results highlight the detrimental effects of RNF114 overexpression in gastric cancer and contribute to a better understanding of the mechanisms underlying RNF114 functionality.

GALNT1 Enhances Malignant Phenotype of Gastric Cancer via Modulating CD44 Glycosylation to Activate the Wnt/β-catenin Signaling Pathway.

O-glycosylation is a widespread post-translational modification of proteins. Aberrant O-glycosylation is a hallmark of cancer. Here, we show that the polypeptide N-acetylgalactosamine-transferase 1 (GALNT1) is frequently upregulated in gastric cancer and is correlated with poor survival. Overexpression of GALNT1 promoted, whereas knockdown suppressed proliferation, migration, and invasion of gastric cancer cells in vitro and in vivo. Mechanistically, GALNT1 enhances aberrant initiation of O-glycosylation and results in CD44 glycoproteins modified with abundant Tn antigens, thereby activating the Wnt/β-catenin signaling pathway. Collectively, this study demonstrates that GALNT1 overexpression in gastric cancer promotes the Wnt/β-catenin signaling pathway via abnormal O-glycosylation of CD44 to enhance malignancy, providing a novel strategy for the development of therapeutic reagents against gastric cancer.

CCNI2 promotes the progression of human gastric cancer through HDGF

BackgroundGastric cancer is a highly aggressive malignant tumor with heterogeneity and is still a global health problem. The present study aimed to investigate the role of Cyclin I-like (CCNI2) in the regulation of phenotype and tumorigenesis, as well as its underlying mechanisms.MethodThe expression profile of CCNI2 in gastric cancer was determined based on The Cancer Genome Atlas (TCGA) database and immunohistochemical staining. The effects of altered CCNI2 expression on the biological phenotypes such as proliferation, clone formation, apoptosis and migration of gastric cancer cell lines BGC-823 and SGC-7901 were investigated. Mice xenograft models were established to reveal the role of CCNI2 knockdown on tumorigenesis. The potential mechanism of CCNI2 regulating gastric cancer was preliminarily determined by RNA sequencing.ResultCCNI2 was abundantly expressed in gastric cancer and was positively correlated with pathological stage. Knockdown of CCNI2 slowed down the malignant progression of gastric cancer by inhibiting tumor cell proliferation, increasing the susceptibility to apoptosis and suppressing migration. Moreover, downregulation of CCNI2 attenuated the ability of gastric cancer cells to form tumors in mice. Additionally, there was an interaction between CCNI2 and transcription factor hepatoma-derived growth factor (HDGF) in SGC-7901 cells. Knockdown of CCNI2 alleviated the promoting effects of HDGF overexpression in gastric cancer cells.ConclusionsCCNI2 promoted the progression of human gastric cancer through HDGF, which drew further interest regarding its clinical application as a potential therapeutic target.

CMAHP promotes metastasis by reducing ubiquitination of Snail and inducing angiogenesis via GM-CSF overexpression in gastric cancer.

Pseudogenes are generally considered "junk" DNA or "genomic fossils" generated during the evolution process that lack biological activity. However, accumulating reports indicate that pseudogenes have biological functions critical for cancer development. Experiments from the current study showed marked overexpression of the cytidine monophospho-N-acetylneuraminic acid hydroxylase pseudogene (CMAHP) in gastric cancer, which was associated with poor overall survival. However, the mechanisms underlying the activity of CMAHP in tumor development are largely unknown. Gene Set Enrichment Analysis (GSEA) revealed that CMAHP-correlated genes are significantly involved in epithelial-mesenchymal transition (EMT) and angiogenesis. Functional studies further confirmed that CMAHP mediates metastasis and angiogenesis in vitro and in vivo. Furthermore, CMAHP promoted cancer cell migration, invasion, and metastasis through Snail overexpression, which decreased ubiquitination mediated by NF-κB signaling. Angiogenesis is known to be induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation. CMAHP increased GM-CSF transactivation via promoting direct binding of c-Jun to the -1981/-1975 region of the GM-CSF promoter. Notably, CMAHP interacts with Histone H1.4 promoting histone acetylation to enhance c-Jun and RelA (p65) expression. Our collective findings provide novel evidence that CMAHP contributes to tumor progression and modulates metastasis and angiogenesis in gastric cancer.