Cancer associated fibroblasts-derived SULF1 promotes gastric cancer metastasis and CDDP resistance through the TGFBR3-mediated TGF-ß signaling pathway.

SULF1 has been implicated in a number of malignancies. The function of SULF1 in gastric cancer is disputed. The objective of this study was to examine the role and underlying molecular mechanisms of SULF1 in the context of gastric cancer. We found that the expression of SULF1 was increased in gastric cancer, especially in cancer-associated fibroblasts. The overexpression of SULF1 was found to be significantly correlated with unfavorable prognosis among individuals diagnosed with gastric cancer. Functionally, cancer-associated fibroblasts-derived SULF1 served as a oncogenic molecule which facilitated gastric cancer cells metastasis and CDDP resistance. Mechanistically, SULF1 regulated the communication between gastric cancer cells and cancer-associated fibroblasts in tumor microenvironment as a signaling molecule. Cancer-associated fibroblasts-secreted SULF1 interfered with the interaction between TGF-ß1 and TGFBR3 by combining with TGFBR3 on gastric cancer cell membrane, subsequently activated TGF-ß signaling pathway. In conclusion, our findings have presented novel approaches for potential treatment and prognosis prediction in individuals diagnosed with gastric cancer through the targeting of the CAFs-SULF1-TGFBR3-TGF-ß1 signaling axis.

Unveiling the oncogenic role of CLDN11-secreting fibroblasts in gastric cancer peritoneal metastasis through single-cell sequencing and experimental approaches.

BACKGROUND: Fibroblasts are necessary to the progression of cancer. However, the role of fibroblasts in peritoneal metastasis (PM) of gastric cancer (GC) remains elusive. In this study, we would explore the role of fibroblasts mediated cell interaction in PM of GC. METHODS: Single-cell sequencing data from public database GSE183904 was used to explore the specific fibroblast cluster. Fibroblasts were extracted from PM and GC tissues. The expression level of CXCR7 was verified by western blot, immunohistochemistry. The role of CLDN11 was investigate through in vitro and in vivo study. Multiple immunohistochemistry was used to characterize the tumor microenvironment. RESULTS: CXCR7-positive fibroblasts were significantly enriched in PM of GC. CXCR7 could promote the expression of CLDN11 through activation of the AKT pathway in fibroblasts. Fibroblasts promote the GC proliferation and peritoneal metastasis by secreting CLDN11 in vitro and in vivo. Furthermore, it was revealed that CXCR7-positive fibroblasts were significantly associated with M2-type macrophages infiltration in tissues. CONCLUSION: CXCR7-positive fibroblasts play an essential role in PM of GC via CLDN11. Therapy targeting CXCR7-positive fibroblasts or CLDN11 may be helpful in the treatment of GC with PM.

N6-methyladenosine-modified MIB1 promotes stemness properties and peritoneal metastasis of gastric cancer cells by ubiquitinating DDX3X.

BACKGROUND: Peritoneal metastasis (PM), one of the most typical forms of metastasis in advanced gastric cancer (GC), indicates a poor prognosis. Exploring the potential molecular mechanism of PM is urgently necessary, as it has not been well studied. E3 ubiquitin ligase has been widely established to exert a biological function in various cancers, but its mechanism of action in GC with PM remains unknown. METHODS: The effect of MIB1 on PM of GC was confirmed in vitro and in vivo. Co-immunoprecipitation (Co-IP) and mass spectrometry demonstrated the association between MIB1 and DDX3X. Western blot, flow cytometry and immunofluorescence determined that DDX3X was ubiquitylated by MIB1 and promoted stemness. We further confirmed that METTL3 promoted the up-regulation of MIB1 by RNA immunoprecipitation (RIP), luciferase reporter assay and other experiments. RESULTS: We observed that the E3 ubiquitin ligase Mind bomb 1 (MIB1) was highly expressed in PMs, and patients with PM with high MIB1 expression showed a worse prognosis than those with low MIB1 expression. Mechanistically, our study demonstrated that the E3 ubiquitin ligase MIB1 promoted epithelial-mesenchymal transition (EMT) progression and stemness in GC cells by degrading DDX3X. In addition, METTL3 mediated m6A modification to stabilize MIB1, which required the m6A reader IGF2BP2. CONCLUSIONS: Our study elucidated the specific molecular mechanism by which MIB1 promotes PM of GC, and suggested that targeting the METTL3-MIB1-DDX3X axis may be a promising therapeutic strategy for GC with PM.

ACLY promotes gastric tumorigenesis and accelerates peritoneal metastasis of gastric cancer regulated by HIF-1A.

Mounting evidence indicates the potential involvement of ATP-citrate lyase (ACLY) in the modulation of various cancer types. Nevertheless, the precise biological significance of ACLY in gastric cancer (GC) remains elusive. This study sought to elucidate the biological function of ACLY and uncover its influence on peritoneal metastasis in GC. The expression of ACLY was assessed using both real-time quantitative PCR and western blot techniques. To investigate the impact of ACLY on the proliferation of gastric cancer (GC) cells, colony formation and 5-ethynyl-2'-deoxyuridine (EdU) assays were performed. The migratory and invasive abilities of GC were evaluated using wound healing and transwell assays. Additionally, a bioinformatics analysis was employed to predict the correlation between ACLY and HIF-1A. This interaction was subsequently confirmed through a chromatin immunoprecipitation (ChIP) assay. ACLY exhibited upregulation in gastric cancer (GC) as well as in peritoneal metastasis. Its overexpression was found to facilitate the proliferation and metastasis of GC cells in both in vitro and in vivo experiments. Moreover, ACLY was observed to play a role in promoting angiogenesis and epithelial-mesenchymal transition (EMT). Notably, under hypoxic conditions, HIF-1A levels were elevated, thereby acting as a transcription factor to upregulate ACLY expression. Under the regulatory influence of HIF-1A, ACLY exerts a significant impact on the progression of gastric cancer, thereby facilitating peritoneal metastasis.

SEC23A confers ER stress resistance in gastric cancer by forming the ER stress-SEC23A-autophagy negative feedback loop.

BACKGROUND: Sec23 homolog A (SEC23A), a core component of coat protein complex II (COPII), has been reported to be involved in several cancers. However, the role of SEC23A in gastric cancer remains unclear. METHODS: The expression of SEC23A in gastric cancer was analyzed by using qRT-PCR, western blotting and IHC staining. The role of SEC23A in ER stress resistance was explored by functional experiments in vitro and vivo. The occupation of STAT3 on the SEC23A promoter region was verified by luciferase reporter plasmids and CHIP assay. The interaction between SEC23A and ANXA2 was identified by Co-IP and mass spectrometry analysis. RESULTS: We demonstrated that SEC23A was upregulated in gastric cancer and predicted poor prognosis in patients with gastric cancer. Mechanistically, SEC23A was transcriptional upregulated by ER stress-induced pY705-STAT3. Highly expressed SEC23A promoted autophagy by regulating the cellular localization of ANXA2. The SEC23A-ANXA2-autophay axis, in turn, protected gastric cancer cells from ER stress-induced apoptosis. Furthermore, we identified SEC23A attenuated 5-FU therapeutic effectiveness in gastric cancer cells through autophagy-mediated ER stress relief. CONCLUSION: We reveal an ER stress-SEC23A-autophagy negative feedback loop that enhances the ability of gastric cancer cells to resist the adverse survival environments. These results identify SEC23A as a promising molecular target for potential therapeutic intervention and prognostic prediction in patients with gastric cancer.

A thirty-three gene-based signature predicts lymph node metastasis and prognosis in patients with gastric cancer.

Recently, several studies have indicated the great potential of gene expression signature of the primary tumor in predicting lymph node metastasis; however, few current gene biomarkers can predict lymph node status and prognosis in gastric cancer (GC). Thus, we used the RNA-seq data from The Cancer Genome Atlas (TCGA) to identify differentially expressed genes between pathological lymph node-negative (pN0) and positive (pN+) patients and to establish a gene signature that could predict lymph node metastasis. Meanwhile, the robustness of identified gene signatures was validated in an independent dataset Asian Cancer Research Group (n = 300). In this study, our thirty-three gene-based signature was highly correlated with lymph node metastasis and could successfully discriminate pN + patients in the training set (Area under the receiver operating characteristic curve = 0.951). Moreover, Disease-free survival (P = 0.0029) and overall survival (P = 0.026) were significantly worse in high-risk compared with low-risk patients overall and when confined to pN0 patients only (P < 0.0001). Of note, this gene signature also proved useful in predicting lymph node status and survival in the validation cohort. The present study suggests a thirty-three gene-based signature that could effectively predict lymph node metastasis and prognosis in GC.

Peritoneal high-fat environment promotes peritoneal metastasis of gastric cancer cells through activation of NSUN2-mediated ORAI2 m5C modification.

Peritoneal metastasis (PM) is an important metastatic modality of gastric cancer (GC).It is associated with poor prognosis. The underlying molecular mechanism of PM remains elusive. 5-Methylcytosine (m5C), a posttranscriptional RNA modification, involves in the progression of many tumors. However, its role in GC peritoneal metastasis remains unclear. In our study, transcriptome results suggested that NSUN2 expression was significantly upregulated in PM. And patients with high NSUN2 expression of PM predicted a worse prognosis. Mechanistically, NSUN2 regulates ORAI2 mRNA stability by m5C modification, thereby promoting ORAI2 expression and further promoting peritoneal metastasis and colonization of GC. YBX1 acts as a "reader" by binding to the ORAI2 m5C modification site. Following the uptake of fatty acids from omental adipocytes by GC cells, the transcription factor E2F1 was upregulated, which further promoted the expression of NSUN2 through cis-element. Briefly, these results revealed that peritoneal adipocytes provide fatty acid for GC cells, thus contributing to the elevation of E2F1 and NSUN2 through AMPK pathway, and upregulated NSUN2 activates the key gene ORAI2 through m5C modification, thereby promoting peritoneal metastasis and colonization of gastric cancer.

Polymorphism rs1057147 located in mesothelin gene predicts lymph node metastasis in patients with gastric cancer.

Lymph node metastasis, a crucial factor in the spread of gastric cancer (GC), is strongly associated with a negative prognosis for patients. This study aimed to investigate the association of the mesothelin (MSLN) gene polymorphisms (rs3764247, rs3764246, rs12597489, rs1057147, and rs3765319) with the risk of lymph node metastasis of GC patients in a Chinese Han population. The PCR-LDR genotyping was used to detect the genotypes of MSLN polymorphisms in GC patients with lymph node metastasis (n = 610) or without (n = 356). Our research indicates that certain genetic markers, specifically rs3764247, rs3764246, rs12597489, and rs3765319, do not appear to be linked with an increased risk of lymph node metastasis in GC. However, we did observe that patients with the rs1057147 GA genotype exhibited a higher likelihood of lymph node metastasis in GC when compared to those with the GG genotype (OR = 1.33, 95% CI = 1.01 - 1.76, P = 0.045). Patients with rs1057147 GA + AA genotype were found to have a higher likelihood of lymph node involvement (OR = 1.35, 95% CI = 1.03 - 1.77, P = 0.029) when compared to those with GG genotype in the dominant model. The allelic model revealed that the A allele of rs1057147 exhibited a stronger correlation with lymph node metastasis compared to the G allele (OR = 1.28, 95% CI = 1.02 - 1.60, P = 0.031). In addition, we found that rs1057147 polymorphism revealed a poor prognosis for GC patients with lymph node metastasis. Further stratified analysis revealed that the prognostic effect of rs1057147 was more pronounced in patients with GC who had lymph node metastasis and had a tumor size of 4 cm or greater, as well as more than 2 lymph node metastases. Bioinformatics studies showed that the binding mode of miR-3144-5p or miR-3619-3p to MSLN was altered by the mutation of rs1057147. Our study confirmed the important role of MSLN rs1057147 polymorphism locus in GC lymph node metastases and suggested a potential prognostic factor during GC progression. KEY POINTS: • Rs1057147 GA genotype had an increased risk of lymph node metastasis in gastric cancer. • The A allele of rs1057147 had a stronger association with lymph node metastasis than the G allele. • The binding mode of miR-3144-5p or miR-3619-3p to MSLN was altered by the mutation of rs1057147.

Rs15285, a functional polymorphism located in lipoprotein lipase, predicts the risk and prognosis of gastric cancer.

Lipoprotein lipase (LPL), a crucial gene in lipid metabolism, has a significant role in the progression of malignant tumors. The purpose of this research was to investigate the impact of rs15285 found in the LPL gene's 3'UTR region on the risk, biological behavior, and gastric cancer (GC) prognosis as well as to examine its potential function. Genotyping of rs15285 in 888 GC cases and 874 controls was conducted by SNaPshot technology. We used bioinformatics analysis and in vitro experiments to study the role of rs15285. First, this study revealed for the first time that polymorphism rs15285 increases the risk of GC (OR = 1.48, 95%CI = 1.16-1.89, P = 0.002). Although no relationship was found between rs12585 and the pathological features of GC, the prognosis of individuals with the rs12585 TT genotype was poorer than that of patients with the CC or CC+CT genotype (HR = 2.39 for TT vs. CC, P = 0.025; HR = 2.38 for TT vs. CC+CT, P = 0.025). In addition, bioinformatics analysis showed rs12585 may affect the binding of miRNAs to LPL, resulting in an increase of LPL expression to promote cancer progression. Ultimately, in vitro tests revealed that the rs15285 T allele increased LPL expression on the mRNA as well as the protein levels, promoting GC cell proliferation, invasion, and metastasis. The LPL rs12528 TT genotype increased the risk of GC and predicted a poor prognosis. Mechanistically, the rs15285 T allele could improve the expression of LPL, and thus promotes the malignant phenotype of GC. Therefore, our study may provide new biological predictors and a theoretical basis for the prognosis and customized therapy of stomach cancer patients. KEY POINTS: • Rs15285 polymorphism is a risk factor for GC. • Rs12585 TT genotype predicts a bad outcome in GC individuals. • Rs15285 T allele enhances GC cells malignant biological behavior.

Long non-coding RNA LGALS8-AS1 facilitates PLAGL2-mediated malignant phenotypes in gastric cancer.

BACKGROUND: Great progress has been made in studying the function of long non-coding RNA (lncRNA) in various tumors, including gastric cancer (GC). However, there are still numerous lncRNAs that have not yet been studied and explored for their roles in GC, and their important functions need to be further revealed. METHODS: Through analyzing The Cancer Genome Atlas (TCGA) database combined with bioinformatics survival tools, a novel GC-related lncRNA LGALS8-AS1 was identified. A quantitative real-time polymerase chain reaction and a series of in vitro or in vivo cell functional experiments were performed to determine the expression and the role of LGALS8-AS1/miR-138-5p/PLAGL2 in GC. RESULTS: LGALS8-AS1 was remarkably upregulated and correlated with the unfavorable prognosis in GC. Higher expression of LGALS8-AS1 was positively associated with higher lymph node metastasis rate, as well as larger tumor size. In addition, a series of cell functional experiments revealed that LGALS8-AS1 could facilitate GC cell proliferation, migration and metastasis in vitro or in vivo. A deeper mechanism exploration revealed that LGALS8-AS1 could function as the miR-138-5p molecular sponge and upregulate the PLAGL2 expression, thereby promoting the cell proliferation, migration and metastasis in GC. CONCLUSIONS: In brief, we revealed the tumor promoting role of the LGALS8-AS1/miR-138-5p/PLAGL2 molecular signaling axis in GC, and our findings provide enlightenment for further understanding of the mechanism of tumorigenesis and development of GC, making LGALS8-AS1 a possible new diagnostic or therapeutic target for GC.

Prognostic Value of Tumor Size in Gastric Cancer: A Retrospective Cohort Study Based on SEER Database.

Background. Although tumor size is regarded as the "T" stage of the tumor-node-metastasis (TNM) staging system for many solid tumors, its prognostic impact in gastric cancer remains uncertain and conflicting. Methods. We enrolled 6960 eligible patients from the Surveillance, Epidemiology, and End Results (SEER) database. The X-tile program was used to select the best cut-off value of tumor size. Then, the Kaplan-Meier method and the Cox proportional hazards model were applied to examine the efficacy of tumor size on prognostic prediction for overall survival (OS) and gastric cancer-specific survival (GCSS). The presence of nonlinear association was determined by the restricted cubic spline (RCS) model. Results. Tumor size was divided into 3 groups: small size (≤2.5 cm), medium size (2.6-5.2 cm), and large size (≥5.3 cm). After adjusting by covariates such as depth of tumor infiltration, the large and medium groups showed a worse prognosis than the small group; however, no survival difference in OS was suggested between the medium and large groups. Similarly, although there was a nonlinear relationship between tumor size and survival, increasing tumor size did not show an independent negative effect on prognosis in the RCS analysis. However, the stratified analyses proposed this 3-way cut of tumor size in prognostic prediction for patients with both inadequate lymphadenectomy and negative nodal metastasis. Conclusions. Tumor size as a prognostic predictor may not have good clinical applicability in gastric cancer. Otherwise, it was recommended for patients with both insufficient examinations of lymph nodes and stage N0 disease.

A novel risk model construction and immune landscape analysis of gastric cancer based on cuproptosis-related long noncoding RNAs.

Recent studies have identified cuproptosis, a new mechanism of regulating cell death. Accumulating evidence suggests that copper homeostasis is associated with tumorigenesis and tumor progression, however, the clinical significance of cuproptosis in gastric cancer (GC) is unclear. In this study, we obtained 26 prognostic cuproptosis-related lncRNAs (CRLs) based on 19 cuproptosis-related genes (CRGs) via Pearson correlation analysis, differential expression analysis, and univariate Cox analysis. A risk model based on 10 CRLs was established with the least absolute shrinkage and selection operator (LASSO) Cox regression analysis and multivariate Cox proportional hazards model to predict the prognosis and immune landscape of GC patients from The Cancer Genome Atlas (TCGA). The risk model has excellent accuracy and efficiency in predicting prognosis of GC patients (Area Under Curve (AUC) = 0.742, 0.803, 0.806 at 1,3,5 years, respectively, P < 0.05). In addition, we found that the risk score was negatively correlated with the infiltration of natural killer (NK) cells and helper T cells, while positively correlated with the infiltration of monocytes, macrophages, mast cells, and neutrophils. Moreover, we evaluated the difference in drug sensitivity of patients with different risk patterns. Furthermore, low-risk patients showed higher tumor mutation burden (TMB) and better immunotherapy response than high-risk patients. In the end, we confirmed the oncogenic role of AL121748.1 which exhibited the highest Hazard Ratio (HR) value among 10 CRLs in GC via cellular functional experiments. In conclusion, our risk model shows a significant role in tumor immunity and could be applied to predict the prognosis of GC patients.

Obesity promotes lipid accumulation in lymph node metastasis of gastric cancer: a retrospective case‒control study.

BACKGROUND: The connection between obesity, lipid accumulation, and lymph node metastasis (LNM) in gastric cancer (GC) is unclear. METHODS: The association of body mass index (BMI) and serum lipid levels with LNM was measured by calculating the odds ratio (OR) and 95% confidence interval (CI) in 1,058 eligible GC patients with a mean age of 61.4 years. Meanwhile, differentially expressed genes (DEGs) were identified between lymph node metastasis-positive (N +) and -negative (N0) groups using public RNA-seq data. Neutral lipids in human GC samples were detected by Oil red O staining. The expression of cluster of differentiation 36 (CD36), fatty acid synthase (FASN), and lipoprotein lipase (LPL) was detected by immunohistochemistry (IHC) and quantitative real-time PCR. RESULTS: Compared with normal-weight patients, overweight (OR = 2.02, 95% CI = 1.26-3.23) and obese (OR = 1.83, 95% CI = 1.15-2.91) patients showed increased ORs for LNM. However, no significant results were obtained for serum lipids in the multivariable-adjusted model (P > 0.05). Subgroup analysis suggested that increased low-density lipoprotein cholesterol was a risk factor in females (OR = 1.27, 95% CI = 1.02-1.59). Functional enrichment analysis of DEGs revealed a connection between lipid metabolism and LNM. Meanwhile, lipid staining showed a mass of lipids in obese N + tumor samples, and IHC analysis indicated an increase in LPL and CD36 expression in N + cases, implying a crucial role for exogenous lipid supply in LNM. CONCLUSIONS: High BMI significantly increases the risk of LNM in GC and promotes lipid accumulation in GC cells in LNM.

Polymorphisms of an oncogenic gene, mesothelin, predict the risk and prognosis of gastric cancer in a Chinese Han population.

Mesothelin (MSLN) is a cell surface protein associated with tumor invasion and metastasis. This study aims to explore the biological function of MSLN in gastric cancer and to evaluate the association of MSLN polymorphism (rs3764247, rs3764246, rs12597489, rs1057147, rs3765319) with the risk and prognosis of gastric cancer. Small interfering RNA (siRNA) transfection and MSLN overexpression were performed in human gastric cancer cell lines, respectively. The proliferation of tumor cells was evaluated by Cell counting kit 8(CCK-8) and colony formation assay. Wound healing assay and transwell assay were used to elucidate gastric cancer cell migration and invasion rates. We conducted a case-control study involving 860 patients with gastric cancer and 870 controls. All mutation sites were genotyped by PCR-LDR sequencing. First, our study revealed the cancer-promoting role of MSLN in gastric cancer. Second, we also demonstrated that rs3764247 and rs3764246 were associated with a reduced risk of gastric cancer (OR = 0.83, p = 0.010; OR = 0.84, p = 0.011; respectively). The clinicopathological analysis further showed that rs3764247 was closely related to T stage, vascular infiltration, and HER2 expression. In addition, in the survival analysis of 392 patients with gastric cancer, patients with rs3764247 CC genotype had poorer survival than patients with AA + AC genotype after adjusting for age, sex, TNM stage, and Lauren classification (HR = 2.07, p = 0.029). Our findings indicated that MSLN could be an oncogene whose polymorphisms were closely related to the risk and prognosis of gastric cancer.

Correlation of MIF-AS1 polymorphisms with the risk and prognosis of gastric cancer.

BACKGROUND: The most studied genetic polymorphisms associated with gastric cancer (GC) risk are located in protein-coding genes. However, the localization of these in long non-coding RNAs (lncRNAs) has not been fully studied. We aim to investigate the associations of Long non-coding RNA macrophage migration inhibitory factor antisense RNA1(Lnc-MIF-AS1) five polymorphisms (rs755622, rs17004044, rs2070767, rs1007889, rs2000468) with the risk and prognosis of GC. METHODS: A total of 844 GC patients and 871 controls were included in the study. Genotyping was carried out using polymerase chain reaction-ligase detection reaction (PCR-LDR) technology. Odds ratios (ORs) and 95% confidence intervals (CIs) generated from unconditional logistic regression, were applied to quantify the effects of MIF-AS1 gene SNPs on GC risk. Log-rank test and Cox regression analysis were fitted to estimate hazard ratios (HRs) to quantify the effects of MIF-AS1 gene SNPs on GC prognosis. RESULTS: Significant associations were identified between MIF-AS1 rs17004044 variants and GC group in the codominant, dominant and additive models (OR = 2.843, P = 0.010; OR = 1.370, P = 0.004; and OR = 1.386; P = 0.001). In addition, association between rs17004044 variants and survival of GC was extremely observed (TC HR = 2.02 (1.21-3.37) P = 0.007, CC HR = 5.61 (2.12-14.83), P = 0.001). CONCLUSION: MIF-AS1 polymorphism rs17004044 contributes to increased predisposition and prognosis to GC.

Long noncoding RNA FAM225A promotes the malignant progression of gastric cancer through the miR-326/PADI2 axis.

Gastric cancer (GC) is a global health problem and further studies of its molecular mechanisms are needed to identify effective therapeutic targets. Although some long noncoding RNAs (lncRNAs) have been found to be involved in the progression of GC, the molecular mechanisms of many GC-related lncRNAs remain unclear. In this study, a series of in vivo and in vitro assays were performed to study the relationship between FAM225A and GC, which showed that FAM225A levels were correlated with poor prognosis in GC. Higher FAM225A expression tended to be correlated with a more profound lymphatic metastasis rate, larger tumor size, and more advanced tumor stage. FAM225A also promoted gastric cell proliferation, invasion, and migration. Further mechanistic investigation showed that FAM225A acted as a miR-326 sponge to upregulate its direct target PADI2 in GC. Overall, our findings indicated that FAM225A promoted GC development and progression via a competitive endogenous RNA network of FAM225A/miR-326/PADI2 in GC, providing insight into possible therapeutic targets and prognosis of GC.