Fibroblast Activation Protein-α-Positive Fibroblasts Promote Gastric Cancer Progression and Resistance to Immune Checkpoint Blockade

Gastric cancer (GC) is one of the main causes of cancer death. The tumor microenvironment has a profound effect on inducing tumor growth, metastasis, and immunosuppression. Fibroblast activation protein-α (FAP) is a protein that is usually expressed in fibroblasts, such as cancer-associated fibroblasts, which are major components of the tumor microenvironment. However, the role of FAP in GC progression and treatment is still unknown. In this study, we explored these problems based on GC patient samples and experimental models. We found that high FAP expression was an independent prognosticator of poor survival in GC patients. FAP+ cancer-associated fibroblasts (CAFs) promoted the survival, proliferation, and migration of GC cell lines in vitro. Moreover, they also induced drug resistance of the GC cell lines and inhibited the antitumor functions of T cells in the GC tumor microenvironment. More importantly, we found that targeting FAP+ CAFs substantially enhanced the antitumor effects of immune checkpoint blockades in GC xenograft models. This evidence highly suggested that FAP is a potential prognosticator of GC patients and a target for synergizing with other treatments, especially immune checkpoint blockades in GC.

LINC00052 Promotes Gastric Cancer Cell Proliferation and Metastasis via Activating the Wnt/β-Catenin Signaling Pathway

Gastric cancer (GC) is one of the most common malignant tumors of the digestive system. The etiology of GC is complex, and much more attention should be paid to genetic factors. In this study, we explored the role and function of LINC00052 in GC. We applied qRT-PCR and Northern blot to detect the expression of LINC00052 and found it was highly expressed during GC. We also investigated the effects of LINC00052 on tumor prognosis and progression and found that LINC00052 indicated poor prognosis and tumor progression. By performing MTT, colony formation, and Transwell assays, we found that LINC00052 promoted MGC-803 cell proliferation and metastasis. Pull-down and RIP assays showed that LINC00052 could interact with β-catenin and methyltransferase SMYD2, and immunoprecipitation detection showed that LINC00052 promoted β-catenin methylation to maintain its stability, so as to activate the Wnt/β-catenin pathway. Furthermore, XAV939 (inhibitor of β-catenin) was used to treat MGC-803 cells, and we found that LINC00052 promoted proliferation and metastasis, possibly by activation of the Wnt/β-catenin pathway. In conclusion, our research demonstrated a carcinogenic role for LINC000052 in GC, which may represent a new approach for the prevention and therapy of this cancer.

MicroRNA 495 Inhibits Proliferation and Metastasis and Promotes Apoptosis by Targeting Twist1 in Gastric Cancer Cells

Recently, microRNAs (miRNAs) have been reported to participate in multiple biological processes. However, the effects of miR-495 on gastric cancer (GC) remain unclear. The purpose of this study was to explore the functions of miR-495 in GC cell proliferation, metastasis, and apoptosis. SGC-7901 and BGC-823 cell lines were transfected with miR-495 mimic, miR-495 inhibitor, and negative controls (mimic control and inhibitor control). The expressions of miR-495, cell viability, migration, apoptosis, and apoptosis-related factors were examined by qRT-PCR, trypan blue staining, Transwell, flow cytometry, and Western blot, respectively. Simultaneously, key factor expression levels of EMT were detected by qRT-PCR and Western blot. The direct target of miR-495 was confirmed by dual-luciferase assay. Additionally, sh-Twist1, pc-Twist1, and corresponding controls were transfected into SGC-7901 and BGC-823 cells, and the protein levels of EMT-associated factors were detected by Western blot. miR-495 was downregulated in GC cells. miR-495 expression level was effectively overexpressed or suppressed in SGC-7901 and BGC-823 cells. Overexpression of miR-495 significantly decreased cell viability and migration, increased apoptosis, and inhibited the EMT process. Suppression of miR-495 showed contrary results. Twist1 was clarified as a target gene of miR-495, and Twist1 silencing obviously reduced the promoting effect of miR-495 suppression on these biological processes. Twist1 silencing significantly blocked the EMT process in both SGC-7901 and BGC-823 cells. miR-495 inhibited proliferation and metastasis and promoted apoptosis by targeting Twist1 in GC cells. These data indicated that miR-495 might be a novel antitumor factor of GC and provide a new method for the treatment of GC.

Knockdown of Rap1b Enhances Apoptosis and Autophagy in Gastric Cancer Cells via the PI3K/Akt/mTOR Pathway

Gastric cancer (GC) is the fourth most common malignancy and the second leading cause of cancer mortality around the world. However, the regulatory mechanisms of GC tumorigenesis and cancer cell motility are completely unknown. We investigated the role of a RAS-related protein (Rap1b) in the progression of GC. Our results showed that the expression of Rap1b is aberrantly upregulated in GC tissue samples and human GC cell lines, and the high expression of Rap1b indicated a positive correlation with poor prognosis in patients with GC. Inhibition of endogenous Rap1b dramatically reduced the cell cycle progression but strongly enhanced the apoptosis capacity of human GC cell lines MKN-28 and SGC-7901 cells compared with the control group. Western blotting assay showed that Rap1b inhibition resulted in a significant increase in the ratio of LC3-II to LC3-I, and the levels of p62 protein were decreased in both MKN-28 and SGC-7901 cells. Furthermore, PI3K/Akt/mTOR activation was found to be maintained in a low level in the normal gastric mucosal epithelial cells, while it was significantly upregulated in GC cells, which could be decreased by Rap1b inhibition. The PI3K inhibitor LY294002 was enhanced but activator insulin-like growth factor 1 (IGF-1) blocked the Rap1b silencing-induced enhancement of apoptosis and autophagy in MKN-28 and SGC-7901 cells. In conclusion, we demonstrate that Rap1b expression is aberrantly increased in GC, resulting in the inhibition of autophagy and apoptosis of GC cells by the PI3K/Akt/mTOR pathway. This might provide a new understanding and represent a novel therapeutic target for human GC.

Silencing of ATP4B of ATPase H+/K+ Transporting Beta Subunit by Intragenic Epigenetic Alteration in Human Gastric Cancer Cells

The ATPase H+/K+ Transporting Beta Subunit (ATP4B) encodes the β subunit of the gastric H+, K+-ATPase, which controls gastric acid secretion and is therefore a target for acid reduction. Downregulation of ATP4B was recently observed in human gastric cancer (GC) without known mechanisms. In the present study, we demonstrated that ATP4B expression was decreased in human GC tissues and cell lines associated with DNA hypermethylation and histone hypoacetylation of histone H3 lysine 9 at its intragenic region close to the transcriptional start site. The expression of ATP4B was restored in GC cell lines by treatment with the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-AZA), or histone deacetylase inhibitor, trichostatin A (TSA), with further enhancement by combined treatment with both drugs. In contrast, 5-AZA had no effect on ATP4B expression in human hepatocellular carcinoma (HCC) and pancreatic cancer cell lines, in which ATP4B was silenced and accompanied by intragenic methylation. Chromatin immunoprecipitation (ChIP) showed that, in BGC823 GC cells, histone H3 lysine 9 acetylation (H3K9ac) was enhanced in the intragenic region of ATP4B upon TSA treatment, whereas 5-AZA showed a minimal effect. Additionally, ATP4B expression enhanced the inhibitory effects of chemotherapeutic mediation docetaxel on GC cell growth. Thus, as opposed to HCC and pancreatic cancer cells, the silencing of ATP4B in GC cells is attributable to the interplay between intragenic DNA methylation and histone acetylation of ATP4B, the restoration of which is associated with a favorable anticancer effect of docetaxel. These results have implications for targeting epigenetic alteration at the intragenic region of ATP4B in GC cells to benefit diagnosis and treatment of GC.

miR-644a Inhibits Cellular Proliferation and Invasion via Suppression of CtBP1 in Gastric Cancer Cells

Epithelial-mesenchymal transition (EMT) is one of the most important mechanisms in the metastasis of various cancers, including gastric cancer (GC). In this study, we explored the putative significance of miR-644a and its role in EMT-mediated metastasis of GC. We first detected the expression of miR-644a in a cohort of 107 GC tissues using quantitative RT-PCR. The expression of miR-644a was suppressed in GC tissues and was associated with a later clinical stage and tumor metastasis. Restoring the expression of miR-644a could significantly suppress the migration and invasion of HGC-27 and SGC-7901 cells, which might be correlated to its suppressive effect on the EMT process. We also found that carboxyl-terminal-binding protein 1 (CtBP1) was a putative target gene of miR-644a in GC and might be involved in the suppressive effect. Collectively, through targeting CtBP1-mediated suppression of the EMT process, miR-644a might suppress the tumor metastasis of GC cells.

Ethnic Disparities in Gastric Cancer Presentation and Screening Practice in the United States: Analysis of 1997-2010 Surveillance, Epidemiology, and End Results-Medicare Data

BACKGROUND

Chronic infection with Helicobacter pylori (H. pylori) is the strongest risk factor for distal gastric cancer. Although gastric cancer incidence has decreased, variation by race and ethnicity is observed. This study describes gastric cancer presentation and screening services among Medicare patients by race/ethnicity, place of birth, and history of gastric cancer-related conditions.

METHODS

Using demographic, location, and disease staging information, extracted from the Surveillance, Epidemiology and End Results-Medicare gastric cancer database (1997-2010), we compared frequencies of gastric cancer-related conditions (e.g., peptic ulcer, gastric ulcer, gastritis) and screening (H. pylori testing and endoscopy) from inpatient and outpatient services claims by selected race/ethnicity and place of birth.

RESULTS

Data included 47,994 incident gastric cancer cases with Medicare claims. The majority (48.0%) of Asian/Pacific Islanders (API) were foreign-born, compared with non-Hispanic whites (NHW), Hispanics, and blacks (with 64.4%, 33.9%, and 72.9% U.S.-born, respectively). For NHWs, the most frequently diagnosed gastric cancer site was the cardia (35.6%) compared with <15% (P < 0.001) for APIs, Hispanics, and blacks. Although more than 57% of all cases had a history of gastric cancer-related conditions, H. pylori testing was reported in only 11.6% of those cases. H. pylori testing was highest for APIs (22.8%) and lowest for blacks (6.5%).

CONCLUSIONS

Noncardia gastric cancer, associated with H. pylori infection, was diagnosed more frequently among APIs, blacks, and Hispanics than NHWs. Testing for H. pylori was low among all gastric cancer cases despite evidence of risk factors for which screening is recommended. Studies are needed to increase appropriate testing for H. pylori among higher risk populations.

IMPACT

This study sheds light on poor screening practices despite presence of gastric cancer-related conditions.

YEATS Domain Containing 4 Promotes Gastric Cancer Cell Proliferation and Mediates Tumor Progression via Activating the Wnt/β-Catenin Signaling Pathway

Increased expression of YEATS domain containing 4 (YEATS4) has been reported to have a correlation with progression in many types of cancer. However, the mechanism by which it promotes the development of gastric cancer (GC) is rarely reported. This study aimed to investigate the effect of YEATS4 on cell proliferation and tumor progression. The mRNA and protein expressions of YEATS4 in GC tissues and cell lines were analyzed. BGC-823 cells then overexpressed or silenced YEATS4 by transfection of different plasmids. The regulatory effect of YEATS on cell viability, colony formation, cell apoptosis, and tumor growth in vivo was evaluated. Finally, we explored the underlying regulatory mechanism of YEATS4 on the Wnt/β-catenin pathway. YEATS4 was highly expressed in GC tissues and cell lines. Furthermore, Kaplan-Meier survival analysis and qRT-PCR analysis showed that the increased expression of YEATS4 indicated poor prognosis and tumor progression. The overexpression of YEATS4 significantly promoted cell proliferation and inhibited cell apoptosis, whereas the opposite trends were found upon the downregulation of YEATS4. Western blot analysis showed that the downregulation of YEATS4 inhibited protein expression and phosphorylation of β-catenin. In addition, decreased expressions of c-Myc, CDK6, CDK4, cyclin D1, and Bcl-2 and increased expression of Bax were observed in YEATS4 knockdown cells. Our results showed that increased expression of YEATS4 might play a critical role in promoting GC cell proliferation and apoptosis by activating the Wnt/β-catenin signaling pathway, indicating that the control of YEATS4 expression might be used as a promising therapy for GC.

Evidence for heightened genetic instability in precancerous spasmolytic polypeptide expressing gastric glands

BACKGROUND

Spasmolytic polypeptide-expressing metaplasia (SPEM) is present in more than 90% of resected gastric cancer tissues. However, although widely regarded as a pre-cancerous tissue, its genetic characteristics have not been well studied.

METHODS

Immunohistochemistry using Trefoil factor 2 (TFF2) antibodies was used to identify TFF2-positive SPEM cells within SPEM glands in the stomach of Helicobacter felis (H. felis) -infected mice and human clinical samples. Laser microdissection was used to isolate specific cells from both the infected mice and the human samples. The genetic instability in these cells was examined by measuring the lengths of microsatellite (MS) markers using capillary electrophoresis. Also, genome-wide genetic variations in the SPEM cells from the clinical sample was examined using deep whole-exome sequencing.

RESULTS

SPEM cells indeed exhibit not only heightened MS instability (MSI), but also genetic instabilities that extend genome-wide. Furthermore, surprisingly, we found that morphologically normal, TFF2-negative cells also contain a comparable degree of genomic instabilities as the co-resident SPEM cells within the SPEM glands.

CONCLUSION

These results, for the first time, clearly establish elevated genetic instability as a critical property of SPEM glands, which may provide a greater possibility for malignant clone selection. More importantly, these results indicate that SPEM cells may not be the sole origin of carcinogenesis in the stomach and strongly suggest the common progenitor of these cells, the stem cells, as the source of these genetic instabilities, and thus, potential key players in carcinogenesis.

Exploring the therapeutic potential of diterpenes in gastric cancer: Mechanisms, efficacy, and clinical prospects

Gastric cancer (GC) remains a significant global health challenge, particularly prevalent in East Asia. Despite advancements in various treatment modalities, the prognosis for patients, especially those in advanced stages, remains poor, highlighting the need for innovative therapeutic approaches. This review explores the promising potential of diterpenes, naturally occurring compounds with robust anticancer properties, derived from diverse sources such as plants, marine organisms, and fungi. Diterpenes have shown the ability to influence reactive oxygen species (ROS) generation, ferroptosis, and autophagy, positioning them as attractive candidates for novel cancer therapies. This review explores the mechanisms of action of diterpenes and their clinical implications for the treatment of GC. Additionally, it addresses the challenges in translating these compounds from preclinical studies to clinical applications, emphasizing the need for further research to enhance their therapeutic profiles and minimize potential side effects. The discussion underscores the importance of diterpenes in future anticancer strategies, particularly in the fight against gastric cancer.

The role of the NY-ESO-1 in the prognosis of gastric cancer

Gastric cancer (GC) is one of the most common malignancies worldwide and the fourth leading cause of cancer-related deaths. GC is a multifactorial disease influenced by both environmental and genetic factors. Its most critical features include invasiveness and high metastatic potential. Metastasis is a complex process, and our understanding of the mechanisms involved remains incomplete. Growing evidence suggests that cancer-testis antigens (CTAs) play a crucial role in the metastatic potential of various tumors. Several studies have linked CTA expression with lower tumor differentiation, higher metastatic potential, and poor chemotherapy response. New York esophageal squamous cell carcinoma-1 (NY-ESO-1) antigen, part of the CTA group, is expressed in tumor tissues, while its expression in normal tissues is restricted to spermatogonia. This study aimed to determine the expression of NY-ESO-1 in primary adenocarcinoma of the stomach, both with and without metastasis in regional lymph nodes, and to compare it with TNM stage, age, gender, and survival. We analyzed GC tissue from 53 node-negative and 55 node-positive primary gastric carcinoma patients for NY-ESO-1 expression using immunohistochemical assay. The results were correlated with clinicopathological parameters and survival. Patients with positive NY-ESO-1 expression in primary tumors had a median survival of 19.0 months (range 14.1-24.0), in contrast to those with negative expression, who had a median survival of 52.0 months (range 0.0-133.3) (chi-square 7.99, P=0.005). T status, N status, and NY-ESO-1 expression were all independently associated with shorter survival. No significant difference in NY-ESO-1 expression in primary tumors was observed concerning lymph node metastasis status. In summary, our findings suggest that increased expression of NY-ESO-1 could potentially serve as a prognostic biomarker for GC.

Perforated Gastric Cancer: A Case Report and Literature Review

Gastric cancer perforation is a rare but life-threatening complication of gastric cancer. We present the case of a 53-year-old male with acquired immune deficiency syndrome (AIDS) who presented to the emergency department with severe abdominal pain, was found to have an acute abdomen, and was eventually diagnosed with gastric perforation due to metastatic gastric cancer. This case highlights the challenges in diagnosing and managing perforated gastric cancer and discusses the surgical management options, including the use of laparoscopic techniques and the role of chemotherapy, particularly hyperthermic intraperitoneal chemotherapy (HIPEC).

An Overview of Current Biomarkers, the Therapeutic Implications, and the Emerging Role of hERG1 Expression in Gastric Cancer: A Literature Review

Gastric cancer remains one of the most commonly diagnosed cancers in the world. It carries a high mortality rate, with cases being more prevalent in the developing world, and has been linked to diet and Helicobacter pylori infection. It is a highly heterogeneous disease, with most cases being of a sporadic nature. Most patients present at an advanced stage due to the asymptomatic nature of the early stages of the disease. A multidisciplinary approach is often best implemented to help decide how to best manage individual cases. However, the overall clinical outcome and survival of patients with advanced gastric cancer remain poor. Recent therapeutic advancements focus on the identification of molecular biomarkers associated with gastric cancer that have predictive, diagnostic, and prognostic implications. This enables the development of specific targeted therapies that have shown efficacy in numerous trials, either as monotherapy or in combination with standard chemotherapy. Despite this, tumour heterogeneity and treatment resistance are still issues leading to poor survival outcomes. An emerging approach is focusing efforts on the bidirectional crosstalk between tumour cells and the microenvironment through targeting ion channels. A key player in this is human ether-á-go-go-related gene 1 (hERG1). This voltage-gated potassium ion channel has been shown to have predictive, diagnostic, and prognostic significance, enabling the stratification of high-risk individuals. In addition, targeting hERG1 in combination with chemotherapy has been shown to potentiate tumour regression. This comprehensive literature review will aim to consolidate our understanding of current biomarkers in gastric cancer. The relevance of hERG1 in gastric cancer as a useful novel biomarker and the potential therapeutic implications as targeted therapy will be explored. This offers a new and personalised approach to helping to manage patients with gastric cancer.

CLEC11A expression as a prognostic biomarker in correlation to immune cells of gastric cancer

Gastric cancer (GC) is a prevalent malignant cancer characterized by a poor survival rate. The C-type lectin domain family 11 member A (CLEC11A) is part of the C-type lectin superfamily, and its dysregulation has been implicated in the progression of several cancers. The specific role of CLEC11A and its association with immune infiltration in GC, however, remains unclear. In this study, we employed The Cancer Genome Atlas (TCGA) database, Gene Expression Omnibus (GEO) database, Tumor IMmune Estimation Resource (TIMER) database, Gene Expression Profiling Interactive Analysis (GEPIA), UALCAN, Kaplan-Meier plotter databases, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA), and the CIBERSORT algorithm to investigate CLEC11A expression, its prognostic significance, its association with tumor immune infiltration, and gene function enrichment in GC. We conducted western blotting, Cell Counting Kit-8 (CCK-8), wound healing, and transwell assays to validate CLEC11A's function. We found that CLEC11A expression was significantly elevated in GC when compared to adjacent non-tumor tissues. Elevated CLEC11A expression was strongly associated with poor survival outcomes and advanced clinicopathological stages.  Moreover, heightened CLEC11A expression positively correlated with immunomodulators, chemokines, and the infiltration of immune cells, especially M2 macrophages, in GC. Additionally, CLEC11A silencing suppressed GC cells proliferation, migration and invasion in vitro. Our results elucidate the functions of CLEC11A in GC, suggesting its potential as a valuable prognostic biomarker and therapeutic target for GC immunotherapy.

Role of Intraoperative Biopsy and Postoperative Upper Gastrointestinal Endoscopy in Patients Undergoing Surgery for Perforated Gastric Ulcer: A Retrospective Study

Introduction The intraoperative biopsy of a perforated gastric ulcer is a common practice; however, it may prove to be therapeutically futile, as an upper gastrointestinal endoscopy (UGE) is indicated regardless of the result. Objective To evaluate the histology of the perforated gastric ulcer biopsy (PGUB) and its effect on the subsequent clinical course. Methods A retrospective study (May 2017 to June 2024) of patients diagnosed with perforated gastric ulcer (K251 and K255 - ICD-10), with a review of medical records in the Medical Support System, was conducted. The histology of the PGUB, the performance of UGE, the degree of concordance between the histology of both, and the potential waiver of UGE were evaluated. Informed consent was waived, as this is an observational study without any interference with clinical conduct. Results During the evaluation period, 21 patients underwent PGUB, and 19 patients had a benign histological result; one patient was diagnosed with high-grade non-Hodgkin lymphoma, and one patient had gastric adenocarcinoma. In the following period, 10 patients underwent UGE, and in none of them did the histological diagnosis change. Of the remaining 11 patients who did not undergo UGE, five died, one was lost to follow-up, three are awaiting the procedure, and only two did not undergo the endoscopic exam. Conclusion The intraoperative biopsy of a perforated gastric ulcer is possibly futile, as it does not alter the clinical course. Regardless of the histological result obtained, a UGE is requested.

Double Digest: A Rare Case Report of Amphicrine Gastric Carcinoma Co-occurring With Papillary Thyroid Carcinoma

With improved cancer treatments and patient lifespans, the incidence of a second cancer diagnosis in a person's lifetime is increasing. While dual cancer diagnoses during one's lifetime are becoming more common, diagnosis with two separate cancers simultaneously is less so. In this report we present a 55-year-old obese woman with a history of chronic lymphocytic thyroiditis and a non-specific family history of thyroid cancer who received synchronous diagnoses of amphicrine carcinoma (AC) and papillary thyroid carcinoma (PTC) during work-up for bariatric surgery. AC is a very rare form of gastric cancer characterized by the presence of both endocrine and epithelial cell components within the same cell with only a few case reports in the literature. This is the first case report to present the co-occurrence of AC with PTC.

The Effectiveness of Albumin-to-Globulin Ratio as a Prognostic Biomarker in Primary Gastrointestinal Cancer: A Systematic Review and Meta-Analysis

Albumin-to-globulin ratio (AGR) is a cheap, widely accessible component of common blood work that has been implicated in the prognosis of various cancers. This effect is attributed to the cooperative relationship between albumin reflecting the body's nutritional status and globulin serving as an indicator of immune status. With the high morbidity and mortality associated with gastrointestinal cancer and the increasing necessity for cost-effective health care, research into AGR's potential as an indicator of prognosis is warranted. A database search, including key terms between AGR and gastrointestinal cancer, was performed. Random-effects meta-analysis was completed on extracted hazard ratios with two-sided p-values <0.05 being deemed significant. A total of 8,384 patients with gastrointestinal cancer were included. A low AGR was found to be associated with increased risk for reduced overall survival in cancer of the primary GI tract (HR: 1.82, 1.35-2.45, p < 0.001), esophageal cancer (HR: 1.57, 1.19-2.06, p < 0.001), colon cancer (HR: 3.36, 2.02-5.58, p < 0.001), and colorectal cancer (HR: 2.27, 1.15-4.48, p = 0.02) populations. A low AGR is significantly associated with increased risk for reduced overall survival in primary gastrointestinal cancer. Due to the ease of access and low cost to physicians and patients, incorporation of AGR into clinical evaluation of prognosis in these cancers should prove beneficial to patient outcomes.