Identification of TAP1 as a T-cell related therapeutic target in gastric cancer by mediating oxalipliatin-related synergistic enhancement of immunotherapy.

BACKGROUND: Given the intricate molecular complexities and heterogeneity inherent in T-cell immunotherapy of gastric cancer (GC), elucidative T-cell-related biomarkers were imperative needed for facilitating the prediction of GC patient prognosis and identify potential synergistic therapeutic targets. METHODS: We conducted COX regression analysis in TISIDB, TCGA-STAD, and GEO databases to identify 19 GC T-cell-mediated sensitivity tumor killing (TTK) genes (key GCTTKs). Based on key GCTTKs, we constructed two TTK patterns and analyzed their metabolic pathways, mutation features, clinical data distribution, immune cell infiltration, and prognosis. LASSO regression was performed to develop a T-cell-mediated GC Prognosis (TGCP) model. We validated the TGCP model in GC patients. TAP1 was further selected for investigation of its biological functions and molecular mechanisms. We assessed the potential of TAP1 as a promising therapeutic target for GC using Patient-derived organoids (PDOs)-derived xenografts (PDOXs) models of GC. RESULTS: The TTK patterns display notable disparities. The TGCP model showcases its proficiency in predicting immune response efficacy, effectively distinguishes immunotherapy difference GC patients. Our findings find further confirmation in PDOX models, affirming TAP1 can enhance immunotherapy facilitated by PDL1 inhibitors. Furthermore, Oxaliplatin, by promoting TAP1 expression, augments PDL1 expression, thereby enhancing the efficacy of immunotherapy. CONCLUSIONS: We constructed a TGCP model, which demonstrates satisfactory predictive accuracy. Out of 9 prognostic genes, TAP1 was validated as a synergistic target for Oxaliplatin and PDL1 inhibitors, offering a genetic-level explanation for the synergy observed in GC treatment involving Oxaliplatin in combination with PDL1 inhibitors.

ATF4-mediated circTDRD3 promotes gastric cancer cell proliferation and metastasis by regulating the miR-891b/ITGA2 axis and AKT signaling pathway.

BACKGROUND: Gastric cancer (GC) is a cancer of the gastrointestinal tract that is highly malignant and has poor prognosis. Circular RNAs are a class of nonclassical RNA molecules that have been determined to be involved in GC malignancy in various ways. However, the underlying function and mechanism of circTDRD3 in gastric cancer remain largely unknown. METHODS: We analyzed circTDRD3 expression in databases and verified the findings in GC cell lines and tissue specimens. A series of functional gene overexpression and knockdown assays in vivo and in vitro were carried out to investigate the role of circTDRD3 in proliferation and metastasis. Here, we revealed the role of the miR-891b/ITGA2 axis by analyzing bioinformatics datasets. Furthermore, we performed dual-luciferase, fluorescence in situ hybridization, RNA pull-down, and functional rescue experiments to examine the relationships between circTDRD3 and its interacting molecules. Western blot confirmed the positive regulatory role of circTDRD3 in the AKT signaling pathway. A promoting effect of ATF4 on circTDRD3 was determined through chromatin immunoprecipitation. RESULTS: CircTDRD3 was significantly overexpressed in GC tissues compared with adjacent benign tissue, and its expression level was positively correlated with tumor volume and lymph node metastasis. CircTDRD3 promoted GC cell proliferation and migration in vitro and in vivo. Mechanistically, circTDRD3 exerted a tumor-promoting effect by regulating the miR-891b/ITGA2 axis and AKT signaling pathway in a positive feedback manner mediated by the transcription factor ATF4. CONCLUSIONS: ATF4-mediated circTDRD3 overexpression modulates the proliferation and metastasis of GC cells through the miR-891b/ITGA2 axis in a positive feedback manner.

Knockdown of Brachyury Suppresses Breast Cancer Cell Proliferation and Migration via Targeting E2F3.

Breast cancer is one of the most frequently diagnosed cancer in women and is the major cause of most cancer-related deaths. We previously reported that Brachyury, as a sensitive and specific marker, has been verified to involve in the process of carcinogenesis and progression of breast cancer, but the mechanism by which Brachyury promotes breast cancer cells proliferation and migration still remains less clear. In this study, we identified that Brachyury was markedly increased in breast cancer compared with the adjacent tissues. We have also shown that Brachyury knockdown could decrease the proliferation and migration capability in breast cancer cells both in vitro and in vivo. Finally, we found an important transcriptional factor, E2F3, which is a direct downstream target gene of Brachyury by chromatin immunoprecipitation (ChIP) analysis. Knockdown of E2F3 also decreased breast cancer cell proliferation and migration. Taken together, we reported that Brachyury may act as an oncogenic role in the progression of breast cancer by positively-regulating E2F3 expression.

Associations of radiological features of adipose tissues with postoperative complications and overall survival of gastric cancer patients.

OBJECTIVES: To evaluate the associations of the radiological features of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) with the postoperative complications and overall survival (OS) of patients undergoing laparoscopic radical gastrectomy for gastric cancer. METHODS: One hundred forty-two patients underwent laparoscopic radical gastrectomy for gastric cancer from February 2013 to May 2016. The radiological features of SAT and VAT were studied by preoperative computed tomography, and the relationships between the parameters of adipose tissues and the intraoperative and postoperative conditions and OS rate of patients were evaluated. RESULTS: A positive linear correlation was found between VAT area and operation duration, and a negative linear correlation was found between VAT density and intraoperative blood loss (p < 0.05 in both). VAT area was an independent risk factor for postoperative complications. VAT area and VAT density were independent risk factors for OS in gastric cancer. CONCLUSIONS: A high VAT area was an independent risk factor for postoperative complications of gastric cancer, whereas a low VAT area and high VAT density were independent risk factors for poor prognosis in terms of OS in gastric cancer. KEY POINTS: • A large visceral adipose tissue (VAT) area is an unfavourable factor affecting the outcomes of radical gastrectomy for gastric cancer. • Low VAT density may be more likely to cause intraoperative bleeding. • VAT area and VAT density were independent risk factors for the OS of patients with gastric cancer.

The characteristics, tumorigenicities and therapeutics of cancer stem cells based on circRNAs.

Currently, recurrence and metastasis are still the main causes leading to the failure of various therapies for malignant tumors. In view of this, research on cancer stem cells (CSCs) has received increasing attention. CSCs are a subgroup of cancer cells with the characteristics of self-renewal, multidirectional differentiation, and immortal proliferation, and are closely related to resistance, metastasis, and recurrence. Circular RNAs (circRNAs) are a type of noncoding RNA (ncRNA) containing a covalent closed loop and are characterized by their abundance, stability, conservation, and tissue specificity. In this article, we focus on the characteristics of CSCs and review the latest research advances on the role of circRNAs in CSCs.

MicroRNA-149: A review of its role in digestive system cancers.

MicroRNAs (miRNAs) are a group of highly conserved, short (18-25 nucleotide long) non-coding RNAs which play important functional roles in cellular differentiation, biological development, pathogenesis and disease susceptibility and have been linked to both tumorigenesis and the malignant progression of various cancers. miRNAs primarily exert their function through the negative regulation of their target gene's transcription via the specific recognition of their 3' untranslated region. A single miRNA can regulate multiple target genes and most miRNAs are controlled by several factors. Recent studies have shown that microRNA-149 (miR-149) plays a pivotal role in the pathogenesis of digestive system cancers and may act as a potential diagnostic marker and therapeutic target. In this review, we summarize and discuss the most recent reports describing miR-149 in digestive system cancers, including its single nucleotide polymorphisms, expression levels, target genes, drug sensitivity and clinical significance.

Inhibition of miR-16 Ameliorates Inflammatory Bowel Disease by Modulating Bcl-2 in Mouse Models.

BACKGROUND: In recent years, microRNA (miRNA) is considered as a potential therapy target. To study the regulatory mechanism and therapeutic effect of miRNAs on inflammatory bowel disease (IBD), we investigated microRNAs that regulate apoptosis-related protein B cell lymphoma-2 (Bcl-2). We examined the role of miR-16 in IBD and the effect of inhibiting the expression of miR-16 on disease progression. MATERIALS AND METHODS: Dextran sulfate sodium was used to induce ulcerative colitis in mice. RNA and protein were extracted from the rectal mucosa of mice. Real-time quantitative polymerase chain reaction and Western blotting were used to detect the expression of miR-16 and Bcl-2. The effects of miR-16 on intestinal mucosal immunity were studied by real-time quantitative polymerase chain reaction, and inflammatory factors such as interleukin-1ß, interleukin-6, and tumor necrosis factor-α were detected. The weight changes, disease activity index, length of the rectal colon, and pathological score of the mice were used to evaluate the effect of inhibiting miR-16 on disease progression. Through the establishment of overexpression and low expression cell lines of miR-16, the regulation of miR-16 on Bcl-2 was studied. RESULTS: MiR-16 was overexpressed in the IBD model, whereas Bcl-2 had lower expression in the mucosa. Inhibiting expression of miR-16 significantly decreased the expression of interleukin-1ß, interleukin-6, and tumor necrosis factor-α. In mice, the weight change, disease activity index, and pathological score decreased in the experimental group, in which miR-16 was inhibited. High expression of miR-16 can inhibit Bcl-2 expression. CONCLUSIONS: MiR-16 plays a critical role in IBD via Bcl-2 and is a promising target in IBD therapy.

Glycyrrhizic Acid Inhibits Proliferation of Gastric Cancer Cells by Inducing Cell Cycle Arrest and Apoptosis.

PURPOSE: Glycyrrhizic acid (GA) is the main active ingredient extracted from Chinese herb licorice root, and it shows anti-tumor effects in many cancer types, while its role in gastric cancer (GC) is still unknown. In this study, we evaluated the effects of GA on GC cells and explored the underlying mechanisms. METHODS: The anti-proliferation effect of GA on GC cells was assessed by CCK-8, colony formation, and EdU assay. The effects of GA on cell cycle and apoptosis were detected by flow cytometer. Western blotting was performed to explore the underlying mechanisms. RESULTS: Our results showed that GA had a time- and dose-dependent inhibitory effect on proliferation of GC cells. Flow cytometer analysis demonstrated that GA would lead to G1/S-phase arrest and apoptosis. GA treatment down-regulated the levels of G1 phase-related proteins, including cyclin D1, D2, D3, E1, and E2. In terms of apoptosis, GA treatment up-regulated the levels of Bax, cleaved PARP, and pro-caspase-3, -8, -9, but did not influence their cleavage patterns. The expression of Bcl-2, survivin and p65 was attenuated after treatment. Besides, GA would down-regulate the phosphorylation of PI3K/AKT pathway. CONCLUSION: This study focused on inhibitory effect of GA on GC cells by inducing cell cycle arrest and apoptosis. Several important cyclins- and apoptosis-related proteins were involved in the regulation of GA to GC cells, and phosphorylated PI3K and AKT were attenuated. The results of this study indicated that GA is a potential and promising anti-cancer drug for GC.

3D Printing Technology Improves Medical Interns' Understanding of Anatomy of Gastrocolic Trunk.

OBJECTIVE: Complex vascular anatomy has always been a difficult point for medical students. Gastrocolic trunk (Henle trunk) has many branches and variations, involving the venous reflux of the stomach, right colon, and pancreas. This study investigated the effects of 3 dimensional (3D) printing technology on medical interns' understanding of Henle trunk's variation, by comparing 2 dimensional (2D) images. SETTING: Henle trunk modes were manufactured using 3D-CT angiography and 3D-printing technology. PARTICIPANTS: Forty-seven interns from 2 medical schools (Nanjing Medical University and Medical College of Nantong University) participated in the study. DESIGN: The interns were divided randomly allocated into 2 groups, where group 1 was the control group with a 2D image of Henle trunk plus surgical video (named 2D image group), and group 2 was the study group with a 3D printed model of Henle trunk plus surgical video (named 3D-printing group). Knowledge of interns on the Henle trunk was compared between 2 groups using a question test before and after the teaching intervention. RESULTS: All interns had an improved overall assessment score as a result of attending the seminar, whether in the 2D image group or the 3D-printing group. The score of the 2D image group increased 32.57 ± 13.86, and the 3D-printing group increased 47.04 ± 12.99, showing significant difference (p = 0.001). There was no significant difference observed between postseminar scores between 2 medical schools (p = 0.975). There was a significant improvement in satisfaction among the 3D-printing group for education depth, novel and inspiring of teaching method, except for the interaction between teacher and interns (p = 0.215). Interns hope to have more teaching time for 3D printing, and not satisfied with the time of 3D printing teaching compared with those in the 2D image group (p = 0.021). CONCLUSIONS: The 3-D printed Henle trunk model is a very effective teaching tool, which can help interns understand the anatomy of Henle trunk. The application of 3D printing technology in the teaching of interns of complex vascular anatomy is worth popularizing in teaching hospitals.

CircRBM33 regulates IL-6 to promote gastric cancer progression through targeting miR-149.

There is increasing evidence of the vital role played by circular RNAs (circRNAs) in the progression of gastric cancer (GC). A circRNA, hsa_circ_0001772, was generated from the RBM33 gene and named circRBM33. The aim of this study was to investigate the role of circRBM33 in GC. Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of circRBM33 in 79 pairs of GC tissues and paracancerous tissues and 4 GC cell lines (MGC-803, BGC-823, SGC-7901, and AGS). Bioinformatics databases were used to predict downstream targets of circRNA and micro RNA (miRNA). Dual luciferase reporter assay was used to verify whether miR-149 was a direct binding target for circRBM33. Cell Counting Kit-8 (CCK-8) assay, 5-Ethynyl-2´-deoxyuridine (EDU) assay, transwell assay, and flow-cytometric analyses were performed to determine the role of circRBM33 in the biological functioning of GC cells. Western blot technique was used to quantify the levels of interleukin-6 (IL-6). CircRBM33 was distinctly upregulated in GC specimens and cell lines and a close correlation between circRBM33 expression and clinical characteristics of GC was observed. After silencing circRBM33, the apoptosis of GC cells increased, while proliferation, migration, and invasion decreased. Rescue experiments indicated that circRBM33 manipulates biological function in GC cells through the circRBM33/miR-149/IL-6 axis. CircRBM33 can be used as a tumor biomarker and a possible therapeutic target in the future.

Tristetraprolin Overexpression in Gastric Cancer Cells Suppresses PD-L1 Expression and Inhibits Tumor Progression by Enhancing Antitumor Immunity.

The RNA-binding protein tristetraprolin (TTP) binds to adenosine-uridine AU-rich elements in the 3'-untranslated region of messenger RNAs and facilitates rapid degradation of the target mRNAs. Therefore, it regulates the expression of multiple cancer and immunity-associated transcripts. Furthermore, a lack of TTP in cancer cells influences cancer progression and predicts poor survival. Although the functions of TTP on cancer cells have previously been researched, the mechanism of TTP on the interaction between cancer cells with their microenvironment remains undiscovered. In this study, we admed to determine the role of cancer cell TTP during the interaction between tumor and immune cells, specifically regulatory T cells (Tregs). We evaluate the capability of TTP to modulate the antitumor immunity of GC and explored the underlying mechanism. The overexpression of TTP in GC cells dramatically increased peripheral blood mononuclear lymphocyte (PBML) -mediated cytotoxicity against GC cells. Increased cytotoxicity against TTP-overexpressed GC cells by PBMLs was determined by Treg development and infiltration. Surprisingly, we found the stabilization of programmed death-ligand 1 (PD-L1) mRNA was declining while TTP was elevated. The PD-L1 protein level was reduced in TTP-abundant GC cells. PD-L1 gas been found to play a pivotal role in Treg development and functional maintenance in immune system. Taken together, our results suggest the overexpression of TTP in GC cells not only affects cell survival and apoptosis but also increases PBMLs -mediated cytotoxicity against GC cells to decelerate tumor progression. Moreover, we identified PD-L1 as a critical TTP-regulated factor that contributes to inhibiting antitumor immunity.

The role of RNA-binding protein tristetraprolin in cancer and immunity.

RNA-binding protein tristetraprolin (TTP) plays a fundamental role in various physiological and pathological processes including differentiation, reprogramming, metabolism, proliferation, pluripotency, tumorigenesis and immunity. Due to its ability to bind and target ARE-containing mRNAs for rapid degradation, TTP down-regulates the expression of a mass of critical genes, thereby functioning as cancer suppressor gene. The loss of TTP has been reported in several human cancers and is relevant to poor prognosis. Recent research shows that TTP also has an emerging significant role in immunity. The aim of this paper is to provide an overview of various roles of TTP in human cancers and immunity. We summarize TTP deficiency in several cancers and discuss that the lack of TTP can influence tumor progression at different aspects such as promoting cancer cell proliferation; accelerating cell cycle; improving survivability and resisting cell death; inducing angiogenesis; activating invasion and metastasis; inducing epithelial-mesenchymal transition; and deregulating cellular energetics. We also pay attention to novel understanding of the relationship between TTP and immunity. Finally, due to its vital role, the disorder of TTP in both cancer and immune cells receives increasing attention and we overview current thinking about regulatory mechanisms of TTP itself expression. This knowledge may contribute to TTP becoming a diagnostic marker for cancer or immune-related diseases and a possible therapeutic target.