KLF5 modulates NTSR1 to facilitate fatty acid oxidation and repress anoikis in gastric cancer.

Validation of Neurotensin Receptor 1 as a Therapeutic Target for Gastric Cancer

BackgroundSeveral reports indicate the high-affinity receptor of NT (neurotensin), NTR1 (neurotensin receptor 1), in numerous detrimental functions linked to neoplastic progression of several cancer types. Recently, it has also been shown that NTR1 gene is a target of the Wnt/APC oncogenic pathways connected with the β-catenin/Tcf transcriptional complex and NT can stimulate cancer proliferation in an EGFR-dependent mechanism. In this study, we explored NTR1, β-catenin and EGFR expression in gastric cancer. The possible associations of NTR1 expression with clinicopathological factors, prognosis, β-catenin and EGFR were analyzed.MethodsNTR1, β-catenin and EGFR expression in gastric cancer tissues and the adjacent normal tissues of 210 cases was detected by Immunohistochemistry. The possible associations of NTR1 expression with clinicopathological data, prognosis, β-catenin and EGFR were analyzed.Results1. NTR1 expression in tumor tissues was significantly higher than that in adjacent normal tissues (P <0 .01). 2. Its expression was positively correlated with pathological grade, T stage, N stage and TNM stage and was not correlated with sex, age, tumor size and Lauren’s classification. 3. A co-expression of NTR1 and nuclear β-catenin was in 53 (25.2 %) of cases and NTR1 expression was positively correlated with β-catenin nuclear translocation. NTR1 expression was not correlated with EGFR expression, but at a critical value (P = 0.05). 4. By log-rank test, higher expression of NTR1, higher pathological grade, diffusion Lauren’s classification and advanced TNM stage showed worse prognosis (P <0 .05). Age, sex, tumor size, β-catenin and EGFR had no prognostic significance. Multivariate Cox analysis showed that NTR1 expression and TNM clinical stage (P <0 .05) were the independent prognostic factors for patients with GC.ConclusionBy immunohistochemistry, we found that a high expression of NTR1 in GC specimens, which showed a bad prognosis, besides, NTR1 expression was related to invasion and migration of GC. These findings provide new and important information on the progression of GC. This study indicated that NTR1 may play an important role in tumor progression of GC and have its potential to be a predictive biomarker or a therapeutic molecular target in GC. The interaction between NTR1 and β-catenin may participate in the development of GC. However, the relationship between NTR1 and EGFR needs to be further investigated.

DNA Hypermethylation Contributes to Incomplete Synthesis of Carbohydrate Determinants in Gastrointestinal Cancer

The promalignant effects of neurotensin (NTS) are sustained in many solid tumors, including hormone-dependent cancers. As the endometrium is also subjected to hormonal regulation, we evaluated the contribution of NTS to endometrial carcinogenesis. Neurotensin receptor 1 (NTSR1) expression and NTSR1 promoter methylation (HM450) were analyzed in 385 cases of endometrial carcinoma from The Cancer Genome Atlas (TCGA). Additionally, from a series of 100 endometrial carcinomas, and 66 benign endometrium samples, NTS and NTSR1 labeling was evaluated by immunohistochemistry. Using TCGA series, NTSR1 messenger RNA (mRNA) level was negatively correlated with overall survival (OS) and progression-free survival (PFS) (p=0.0012 and p=0.0116, respectively), and positively correlated with the grade (p=0.0008). When including only endometrioid carcinomas, NTSR1 mRNA level continued to be negatively correlated with OS (log-rank: p<0.0001) and PFS (log-rank: p=0.002). A higher NTSR1 mRNA level was significantly associated with a loss of NTSR1 promoter methylation. Immunohistochemical expression of NTS and NTSR1 was significantly increased in adenocarcinoma (n=100), as compared to benign endometrium (p<0.001). NTSR1 expression was positively correlated with grade (p=0.004). High immunohistochemical expression of cytoplasmic NTSR1 was significantly correlated with a shorter OS and PFS (p<0.001 and p=0.001, respectively). This correlation remained significant when excluding non-endometrioid subtypes (p=0.04 and p=0.02, respectively). In multivariate analysis, the expression of NTSR1 was an independent prognostic factor (p=0.004). NTSR1 overexpression is a poor prognostic factor in endometrial cancer, highlighting the contribution of NTS in endometrial cancer progression and its uses as a prognostic marker, and as a potential therapeutic target.

To investigate the expression of long non-coding RNA zinc-finger E-box binding homeobox 1-AS1 (lncRNA ZEB1-AS1) in gastric cancer cells and tissues, to study its effect on the gastric cancer cell metastasis capacity, and analyze its clinical significance. The relative expression level of lncRNA ZEB1-AS1 in gastric cancer cells was detected via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Transwell assay was used to detect the effects of lncRNA ZEB1-AS1 on the invasion and metastasis capacities of gastric cancer cells. qRT-PCR was used to detect the relative expression level of lncRNA ZEB1-AS1 in 75 pairs of gastric cancer tissues, and the correlations of its expression with the pathological characteristics and prognosis of patients were statistically analyzed. qRT-PCR showed that compared with that in the normal gastric epithelial cell (GES-1), the expression level of lncRNA ZEB1-AS1 was up-regulated in gastric cancer cells (MKN28, MKN45, BGC823, MGC803, KATOIII, and SGC7901). LncRNA ZEB1-AS1 interfering sequence was transfected into model cells, and Transwell assay showed that the cell invasion and migration capacities were significantly inhibited. qRT-PCR also revealed that the expression of lncRNA ZEB1-AS1 was up-regulated in 55 out of 75 cases of gastric cancer and para-carcinoma tissues (fold change > 1). Statistical analysis showed that the high expression of lncRNA ZEB1-AS1 was positively correlated with TNM staging (p = 0.002), lymph node metastasis (p = 0.002), and invasion degree (p = 0.004). The survival time of patients with high expression of lncRNA ZEB1-AS1 in gastric cancer tissues was shorter than that of patients with low expression (p = 0.004). LncRNA ZEB1-AS1 is highly expressed in gastric cancer tissues and cells, and it is expected to be a new prognostic marker of gastric cancer used for the clinical diagnosis and prognostic evaluation. After intervention in lncRNA ZEB1-AS1 expression, the cell invasion and migration are inhibited, and lncRNA ZEB1-AS1 may be an important target to reverse the malignant phenotype of gastric cancer.

The aim of this study was to examine the expression of circ-CCDC66 in gastric cancer (GC) tissues and cell lines, as well as its correlation with the prognosis of GC. Moreover, the regulatory effects of circ-CCDC66 on biological behaviors of GC cells and its molecular mechanism were explored. The relative expression level of circ-CCDC66 in GC tissues and cell lines was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The correlation between the circ-CCDC66 level and overall survival of GC patients was analyzed as well. The potential influences of circ-CCDC66 on proliferative and invasive abilities of GC cells were evaluated through 5-Ethynyl-2'-deoxyuridine (EdU), colony formation and transwell assay, respectively. Meanwhile, the cell cycle progression and apoptosis of GC cells affected by circ-CCDC66 were determined. In addition, the direct target miRNA of circ-CCDC66 was predicted and verified by bioinformatics method and Dual-Luciferase reporter gene assay, respectively. Circ-CCDC66 was significantly up-regulated in GC tissues and cell lines. Up-regulation of circ-CCDC66 indicated markedly worse prognosis of GC patients. Transfection of circ-CCDC66-siRNA remarkably attenuated proliferative and invasive abilities of BGC-823 and MGC-803 cells. Besides, GC cells were arrested in the G0/G1 phase, and the apoptotic rate was remarkably elevated after circ-CCDC66 knockdown. The Dual-Luciferase reporter gene assay verified that circ-CCDC66 bind to miRNA-1238-3p by competing with LHX2 (LIM-homeobox domain 2). MiRNA-1238-3p was significantly down-regulated in GC cells, whereas LHX2 was up-regulated. Furthermore, overexpression of miRNA-1238-3p in GC cells markedly suppressed the LHX2 level. Circ-CCDC66 is highly expressed in GC tissues and cell lines. Knockdown of circ-CCDC66 attenuates proliferative and invasive abilities of GC cells. Our results indicate that circ-CCDC66/miRNA-1238-3p/LHX2 axis may be a promising target for GC treatment.

ObjectiveTo investigate Krüppel-like factor 17 (KLF17) expression in normal and gastric cancer tissues and cell lines.MethodsLevels of KLF17 mRNA and protein in GES-1 normal gastric mucosal cells, and NCI-N87, SGC-7901, BGC-823 and HGC-27 gastric cancer cells were analysed by quantitative polymerase chain reaction (qPCR) and western blot. Differences in KLF17 expression between gastric cancer and adjacent tissues were analysed by qPCR and immunohistochemistry. Invasion/migration effects of KLF17 overexpression in BGC-823 and HGC-27 cells were analysed by wound-healing and Transwell chamber assays. Changes in expression of KLF17 and epithelial–mesenchymal transition (EMT)-related genes (matrix metalloproteinase [MMP]-9, vimentin and E-cadherin) were analysed in BGC-823 and HGC-27 cells before and after transfection using qPCR and western blot. Transforming growth factor (TGF)-β1, Smad family member (Smad)2/3 and phosphorylated-Smad2/3 levels in BGC-823 and HGC-27 cells were assessed by qPCR and western blot.ResultsKLF17 expression was lower in gastric cancer versus adjacent tissues, and in gastric cancer cell lines versus GES-1 normal gastric mucosal cells, and was positively correlated with degree of cancer-cell differentiation. Wound-healing and Transwell assays showed decreased migration and invasion ability of BGC-823 and HGC-27 cells transfected to overexpress KLF17. KLF17 overexpression was associated with decreased MMP-9 and vimentin in BGC-823 and HGC-27 cancer cells, and increased KLF17 and E-cadherin. KLF17 overexpression also resulted in decreased levels of TGF-β1 and p-Smad2/3 in BGC-823 and HGC-27 cancer cells.ConclusionKLF17 is poorly expressed in gastric cancer tissues and cell lines. KLF17 overexpression might inhibit EMT via the TGF-β/Smad pathway, thereby reducing gastric cancer cell invasion and migration. Therefore, KLF17 may become a novel target for treating gastric cancer.

Platinum-based and pyrimidine drugs are first-line treatments for gastric cancer (GC), but their efficacy is often affected by drug resistance. High spalt-like transcription factor 4 (SALL4) expression is associated with poor prognosis, but its role in 5-fluorouracil (5-FU) resistance is not yet clear. In this study, we investigated the effect of SALL4 on 5-FU resistance in GC cells by bioinformatics analysis, real-time quantitative reverse transcription polymerase chain reaction, cell counting kit-8, colony formation assay, and western blot. The results showed that SALL4 was highly expressed in GC and significantly correlated with the fatty acid oxidation (FAO) pathway. Knockdown of SALL4 resulted in a notable attenuation of cellular proliferative capacity and heightened susceptibility to 5-FU resistance in GC cells, while overexpression of SALL4 enhanced 5-FU resistance. Rescue assays confirmed that SALL4 fostered 5-FU resistance in GC cells by enhancing FAO. Our research confirmed that SALL4 promoted the resistance of GC cells to 5-FU by enhancing the FAO pathway. This suggests that drug development targeting SALL4 may help overcome chemotherapy resistance in GC.

Carcinoma-associated fibroblasts (CAFs) are one of the crucial parts of in the tumor microenvironment and contribute to tumor progression. Interleukin-33 (IL-33), a tissue-derived nuclear cytokine from the IL-1 family, has been found abnormally expressed in tumor cells and Fibroblast. However, the role and mechanism of IL-33 in the interaction between gastric cancer (GC) cells and CAFs need investigation. Presently, we inquire into the function of lncRNA NORAD-miR-496 axis-mediated IL-33 in modulating the GC-CAFs interaction. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was adopted to gauge the expression of NORAD, miR-496, and IL-33 in GC tissues and cells, and gain- or loss-of-function assays were conducted to investigate the role of them in GC. A GC cell-CAFs co-culture model was established to explore the interaction between CAFs and GCs. As exhibited, NORAD was up-regulated in GC tissues and cells, while miR-496 was remarkably down-regulated. Overexpressing NORAD substantially promoted the proliferation, migration, invasion, and EMT of GC cells and repressed cell death, while overexpressing miR-496 had the opposite effects. Additionally, NORAD enhanced the IL-33 expression and the release of IL-33 from GC cells. The dual-luciferase reporter assay confirmed that miR-496 was a target of NORAD and targeted IL-33. CAFs aggravated the malignant behaviors of GC cells as indicated by both experiments. However, NORAD knockdown in CAFs reversed CAFs-mediated promotive effects on GC cells. In conclusion, NORAD enhanced the promotive effect of CAFs in GC cells by up-regulating IL-33 and targeting miR-496, which provided new insights into the microenvironment of GC cells and CAFs. Abbreviation ANOVA: Analysis of Variance; BCA:Bicinchoninic acid; CAFs: carcinoma-associated fibroblasts; CCK-8: cell counting kit-8; ceRNA: competing endogenous RNA; DAPI: 4′,6-diamidino-2-phenylindole; DMEM: Dulbecco’s minimal essential medium/Ham’s; ECL: enhanced chemiluminiscent; ELISA: Enzyme-Linked Immunosorbent Assay; EMT: epithelial-mesenchymal transition; FBS: fetal bovine serum; FISH:Fluorescence in situ hybridization; FITC:fluorescein isothiocyanate; FSP:fibroblast-specific protein; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GC: gastric cancer; IHC: immunohistochemistry; IL: Interleukin; lncRNA: long Noncoding RNA; miR-496: microRNA-496; MMP-14:matrix metalloproteinase-14; MUT:mutant; MYH9: myosin heavy chain 9; NFs: normal fibroblasts; NORAD: Noncoding RNA activated by DNA damage; ORF: open reading frame; PBS: phosphate-buffered saline; PMSF: Phenylmethylsulfonyl fluoride; PVDF: polyvinylidene difluoride; RIPA: Radio-Immunoprecipitation Assay; RT-PCR: Real-time reverse transcription polymerase chain reaction; S100A4:S100 calcium binding protein A4; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; sh-NC: short-hairpin RNA negative control; sh-NORAD: short-hairpin RNA of NORAD; α-SMA: α-smooth muscle actin; TBST: Tris-buffered saline with Tween-20; TGF-β1: Transforming growth factor β1; TUNEL: TdT-mediated dUTP Nick-End Labeling; TWIST1: the twist-related protein 1; VEGF-C: vascular endothelial growth factor C; WT: Wildtype.

FGA inhibits metastases and induces autophagic cell death in gastric cancer via inhibiting ITGA5 to regulate the FAK/ERK pathway

ObjectivesGlucose transporter 3 (GLUT3) plays a major role in glycolysis and glucose metabolism in cancer cells. We aimed to investigate the correlation between GLUT3 and histone lactylation modification in the occurrence and progression of gastric cancer.Materials and methodsWe initially used single-cell sequencing data to determine the expression levels of GLUT3 and lactate dehydrogenase A (LDHA) in primary tumor, tumor-adjacent normal, and metastasis tumor tissues. Immunohistochemistry analysis was conducted to measure GLUT3, LDHA, and L-lactyl levels in gastric normal and cancer tissues. Transwell and scratch assays were performed to evaluate the metastatic and invasive capacity of gastric cancer cell lines. Western blotting was used to measure L-lactyl and histone lactylation levels in gastric cancer cell lines.ResultsSingle-cell sequencing data showed that GLUT3 expression was significantly increased in primary tumor and metastasis tumor tissues. In addition, GLUT3 expression was positively correlated with that of LDHA expression and lactylation-related pathways. Western blotting and immunohistochemistry analyses revealed that GLUT3 was highly expressed in gastric cancer tissues and cell lines. GLUT3 knockdown in gastric cancer cell lines inhibited their metastatic and invasive capacity to various degrees. Additionally, the levels of LDHA, L-lactyl, H3K9, H3K18, and H3K56 significantly decreased after GLUT3 knockdown, indicating that GLUT3 affects lactylation in gastric cancer cells. Moreover, LDHA overexpression in a GLUT3 knockdown cell line reversed the levels of lactylation and EMT-related markers, and the EMT functional phenotype induced by GLUT3 knockdown. The in vivo results were consistent with the in vitro results.ConclusionsThis study suggests the important role of histone lactylation in the occurrence and progression of gastric cancer, and GLUT3 may be a new diagnostic marker and therapeutic target for gastric cancer.

The aim of the present study was to investigate the effect of the long noncoding RNA HIT000218960 on gastric cancer cell resistance to 5-fluorouracil (5-FU) and to explore the underlying molecular mechanism. HIT000218960 expression was measured in gastric cancer tissues and cells lines using reverse transcription-quantitative PCR and western blotting. Gastric cancer cell lines with overexpressed or repressed HIT000218960 levels were generated to study its influence on apoptosis induced by 5-FU, which was analyzed using flow cytometry analysis. Compared with those in normal gastric mucosal tissues and non-cancerous gastric mucosal epithelial cells, HIT000218960 and high mobility group A2 (HMGA2) proteins were found to be upregulated in gastric cancer tissues and cells. Additionally, a positive correlation was found between the expression of HIT000218960 and HMGA2 in gastric cancer tissues. In patients with gastric cancer, HIT000218960 expression was revealed to associate negatively with the efficacy of chemotherapy and 3-year overall survival rate. Overexpression of HIT000218960 suppressed apoptosis in SNU-5 cells, whilst HIT000218960 knockdown increased the apoptosis of NCI-N87 cells following 5-FU treatment. Downstream, HIT000218960 was demonstrated to promote HMGA2 protein expression in gastric cancer cells. In these cells, knocking down HMGA2 expression significantly increased apoptosis in addition to reducing AKT, mTOR and P70S6 kinase (P70S6K) phosphorylation after 5-FU treatment. In conclusion, HIT000218960 is overexpressed in gastric cancer tissues and cells, which is associated with the efficacy of chemotherapy. Mechanistically, this may be mediated by the upregulation HMGA2 expression and AKT/mTOR/P70S6K signaling.

Introduction: Gastric cancer (GC) is the third leading cause of cancer-associated mortality and the fifth most frequently diagnosed cancer worldwide. The development and progression of GC is a complicated multistage process subjected to dynamic changes in gene regulation. Investigating the effects of these changes is therefore critical for improving our knowledge about GC initiation and progression. Krüppel-like factors (KLFs) are evolutionarily conserved zinc finger-containing transcription factors with altered expressions and diverse regulatory functions in GC. We previously reported that there is loss of KLF4 in GC. Here we report that KLF4 is a crucial regulator of KLF5 expression and vice versa and together they regulate GC cell behavior. Methods: The Cancer Genome Atlas (TCGA) and pan cancer data of differential expressions of KLFs in GC was analyzed. TCGA RNAseq and clinical data for the differential expression status of KLF genes in normal and cancerous tissues and the clinicopathological association was accessed from the UALCAN web portal. The expressions of KLF4 and KLF5 in human normal stomach and GC and orthotopic xenografts were detected by immunohistochemistry (IHC). KLF4, KLF5 cross regulation was evaluated by gene manipulation of each gene individually and checking the expression of the other factor in GC cells. The effect of KLFs on GC cell proliferation, migration, and invasion was determined by Ki67 staining of tissues, PrestoBlue cell viability assay, scratch wound and transwell cell invasion assays. Results and Conclusion: Our results indicated that not only KLF4 and KLF5 have contrasting expressions and effects in GC but also these two factors cross regulate each other. While lower expressions of KLF4 was found in human GC and orthotopic xenografts, increased expression of KLF5 was found in both human GC tissue and orthotopic xenografts. KLF4 silencing and CRISPR/Cas9 knockdown in human GC cells resulted in increased expression of KLF5 which was associated with increased GC cell proliferation and invasiveness. Interestingly, KLF5 knockdown by CRISPR/Cas9 in human GC cells on the other hand resulted in increased expression of KLF4, which was associated with decreased GC cell growth. Our data therefore suggests that the differential expressions of KLF4 and KLF5 might serve as valuable prognostic markers in GC. Citation Format: Sooraj Kakkat, Prabhat Suman, Sandeep Goswami, Sujit Basu, Martin J. Heslin, Elba A. Turbat-Herrera, Veronica Ramirez Alcantara, Chandrani Sarkar, Debanjan Chakroborty. Krüppel-like factors in regulation of gastric cancer progression [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 3034.

Tu1908 Differential Expression and Tumorigenic Function of Neurotensin Receptor 1 in Neuroendocrine Tumor Cells

Studies have found that hsa_circ_103809, a newly discovered circRNA in recent years, can serve as an oncogene involved in the progression of hepatocellular carcinoma. However, its role in gastric cancer (GCa) remains elusive. The aim of this study was to reveal the molecular mechanism of hsa_circ_103809 affecting the process of GCa, thus providing new ideas for its treatment. Hsa_circ_103809 expression in GCa and adjacent tissues specimens were studied by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) analysis, and its effect on the prognosis of GCa patients was analyzed. In GCa cells lines, hsa_circ_103809 was knocked down by small interfering RNA, and GCa cell metastasis ability was detected by cell wound healing test and transwell assay. Finally, the potential target gene of hsa_circ_103809 was predicted through bioinformatics website and verified by Luciferase assay. Hsa_circ_103809 showed an increased expression both in GCa tissues and cell lines, predicting a poor prognosis of GCa patients. Meanwhile, the invasive and migration capacities of GCa cells were remarkably reduced after the knockdown of hsa_circ_103809. Bioinformatics website predicted that there existed binding sites of hsa_circ_103809 on microRNA-101-3p, and Luciferase assay verified that hsa_circ_103809 can adsorb microRNA-101-3p. In GCa tissues, qPCR detected a significantly reduced expression of microRNA-101-3p, which was negatively correlated with that of hsa_circ_103809. In addition, the knockdown of hsa_circ_103809 enhanced microRNA-101-3p expression in GCa cell lines. Subsequent in vitro experiments further detected that the overexpression of hsa_circ_103809 partially reversed the inhibitory effect of microRNA-101-3p overexpression on GCa cell migration ability and invasiveness. Hsa_circ_103809, highly expressed in GCa, may promote the migration capacity of GCa cells by adsorbing microRNA-101-3p and thus become a new therapeutic target for GCa.