ATB0,+-targeted nanoparticles trigger STAT3-ferroptosis regulatory axis for enhanced gastric cancer therapy.

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

What is the central question of this study? Does hsa_circ_001653 influence the development of gastric cancer (GC) and if so how? What is the main finding and its importance? Bioinformatics analysis revealed the presence of differentially expressed hsa_circ_001653 in GC and adjacent normal tissues, and this was strongly related to the pathology of patients with GC. Knockdown of hsa_circ_001653 suppressed the proliferation, invasion and migration of GC cells, while inducing cell apoptosis via miR-377-mediated NR6A1 inhibition. The effect of hsa_circ_001653 and miR-377 on tumour growth in GC was further confirmed in vivo. Gastric cancer (GC) is one of the leading causes of human mortality through malignant tumours. Circular RNAs (circRNAs) have been identified as binding to microRNAs (miRNAs) to modulate the progression of tumours. This study explores the role of hsa_circ_001653, a newly identified circRNA, in the development of GC. hsa_circ_001653 expression was measured in 86 paired normal and tumour tissues surgically resected from GC patients. Cross-talk between hsa_circ_001653 and microRNA-377 (miR-377)/nuclear receptor subfamily 6, group A, member 1 (NR6A1) was assessed using bioinformatics analysis, dual-luciferase reporter assay, Ago2 immunoprecipitation and western blot analysis. A series of functional experiments were carried out to elucidate the role of hsa_circ_001653 in GC cell proliferation, invasion, migration and apoptosis, and its underlying molecular mechanisms. Nude mice were inoculated with GC cells for in vivo analysis. hsa_circ_001653 was found to be an up-regulated circRNA in GC tissues and cells. Down-regulation of hsa_circ_001653 inhibited GC cell proliferation, migration and invasion, while stimulating cell apoptosis. hsa_circ_001653 was found to bind to miR-377, which targeted NR6A1 and repressed its expression. Inhibition of miR-377 and overexpression of NR6A1 restored the proliferation, migration and invasion in GC cells lacking hsa_circ_001653. Furthermore, inhibition of hsa_circ_001653 attenuated tumour growth in nude mice inoculated with GC cells. Collectively, the demonstration that hsa_circ_001653 exerts its anticancer effects by regulating the miR-377-NR6A1 axis increases our understanding of gastric cancer pathophysiology. The findings uncover new potential therapeutic targets for GC.

Currently, multiple circular RNAs (circRNAs) have been verified to act as essential regulators in the progression of gastric cancer (GC). We aimed to investigate the role of circ_0008035 in GC progression. Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to measure the expression of circ_0008035 and miR-599. 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was employed to evaluate cell proliferation and ferroptosis. Western blot assay was performed to measure the levels of cyclin D1, proliferating cell nuclear antigen (PCNA) and eukaryotic initiation factor 4A1 (EIF4A1). Flow cytometry analysis was conducted to assess cell apoptosis. The iron accumulation, lipid peroxidation and mitochondrial membrane potential were examined by relevant kits. Dual-luciferase reporter assay was conducted to determine the targeting relationship between miR-599 and circ_0008035 or EIF4A1. A murine xenograft model was established to investigate the function of circ_0008035 in vivo. Circ_0008035 was up-regulated in GC tissues and cells. Silencing of circ_0008035 repressed cell proliferation and induced cell apoptosis and ferroptosis in GC cells. Circ_0008035 acted as a sponge of miR-599. The effects of circ_0008035 knockdown on GC cell proliferation, apoptosis and ferroptosis were abolished by miR-599 inhibition. EIF4A1 was confirmed to be a target gene of miR-599. Circ_0008035 knockdown inhibited EIF4A1 expression by targeting miR-599. Moreover, the suppressive role of circ_0008035 deficiency in GC progression could be restored by EIF4A1. Additionally, circ-0008035 knockdown hampered tumorigenesis in vivo. Circ_0008035 promoted GC cell growth and repressed apoptosis and ferroptosis by up-regulating EIF4A1 through sponging miR-599.

BackgroundCurrently, multiple circular RNAs (circRNAs) have been verified to act as essential regulators in the progression of gastric cancer (GC). We aimed to investigate the role of circ_0008035 in GC progression.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was utilized to measure the expression of circ_0008035 and miR-599. 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was employed to evaluate cell proliferation and ferroptosis. Western blot assay was performed to measure the levels of cyclin D1, proliferating cell nuclear antigen (PCNA) and eukaryotic initiation factor 4A1 (EIF4A1). Flow cytometry analysis was conducted to assess cell apoptosis. The iron accumulation, lipid peroxidation and mitochondrial membrane potential were examined by relevant kits. Dual-luciferase reporter assay was conducted to determine the targeting relationship between miR-599 and circ_0008035 or EIF4A1. A murine xenograft model was established to investigate the function of circ_0008035 in vivo.ResultsCirc_0008035 was up-regulated in GC tissues and cells. Silencing of circ_0008035 repressed cell proliferation and induced cell apoptosis and ferroptosis in GC cells. Circ_0008035 acted as a sponge of miR-599. The effects of circ_0008035 knockdown on GC cell proliferation, apoptosis and ferroptosis were abolished by miR-599 inhibition. EIF4A1 was confirmed to be a target gene of miR-599. Circ_0008035 knockdown inhibited EIF4A1 expression by targeting miR-599. Moreover, the suppressive role of circ_0008035 deficiency in GC progression could be restored by EIF4A1. Additionally, circ-0008035 knockdown hampered tumorigenesis in vivo.ConclusionCirc_0008035 promoted GC cell growth and repressed apoptosis and ferroptosis by up-regulating EIF4A1 through sponging miR-599.

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

MicroRNA-19a regulates the proliferation, migration and invasion of human gastric cancer cells by targeting CUL5

B-cell-specific Moloney murine leukemia virus integration site 1 knockdown impairs adriamycin resistance of gastric cancer cells

A transverse colon lipoma complicated with an adenoma is successfully and safely resected en bloc by endoscopic mucosal resection during water immersion

Gastric cancer is a common cancer of the digestive system. Long non-coding RNA (lncRNA) plays an important role in the formation and development of gastric cancer. This study aims to investigate the effect of long non-coding lncRNA 114227 on biologic behaviors in gastric cancer cells. The experiment was divided into 4 groups: a negative control (NC) group, a lncRNA 114227 small interference (si-lncRNA 114227) group, an empty vector (Vector) group, and an overexpression vector (OE-lncRNA 114227) group. The expressions of lncRNA 114227 in gastric mucosa and gastric cancer tissues, gastric mucosal epithelial cells and different gastric cancer strains were determined by real-time reverse transcription PCR (real-time RT-PCR).The proliferation were detected by CCK-8 assay in gastric cancer cells. The epithelial-mesenchymal transformation (EMT) was utilized by Transwell assay, scratch healing assay, and Western blotting in gastric cancer cells. The effect of lncRNA 114227 on proliferation of gastric cancer cells was detected by tumor bearing experiment in nude mice in vivo. The expression level of lncRNA 114227 in the gastric cancer tissues was significantly lower than that in the gastric mucosa tissues, and in 4 kinds of gastric cancer strains was all significantly lower than that in gastric mucosal epithelial cells (all P<0.01). In vitro, the proliferation and migration abilities of gastric cells were significantly reduced after overexpressing lncRNA 114227, and cell proliferation and migration were enhanced after silencing lncRNA 114227 (all P<0.05). The results of in vivo subcutaneous tumorigenesis in nude mice showed that the tumorigenic volume of the tumor-bearing mice in the OE-lncRNA 114227 group was significantly smaller than that of the Vector group, and the tumorigenic quality was lower than that of the Vector group (P<0.05), indicating that lncRNA 114227 inhibited tumorigenesis. The expression of lncRNA 114227 is downregulated in gastric cancer gastric cancer tissues and cell lines. LncRNA 114227 may inhibit the proliferation and migration of gastric cancer cells through EMT process.

Oxaliplatin is one of the most commonly used chemotherapeutic agents in the treatment of various cancers, including gastric cancer. It has, however, a narrow therapeutic index due to its toxicity and the occurrence of drug resistance. Therefore, there is a pressing need to develop novel therapies to potentiate the efficacy and reduce the toxicity of oxaliplatin. Piperlongumine (PL), an alkaloid isolated from Piper longum L., has recently been identified as a potent agent against cancer cells in vitro and in vivo. In the present study, we investigated whether PL can potentiate the antitumor effect of oxaliplatin in gastric cancer cells. Cellular apoptosis and ROS levels were analyzed by flow cytometry. Thioredoxin reductase 1 (TrxR1) activity in gastric cancer cells or tumor tissues was determined using an endpoint insulin reduction assay. Western blotting was used to analyze the expression levels of the indicated proteins. Nude mice xenograft models were used to test the effects of PL and oxaliplatin combinations on gastric cancer cell growth in vivo. We found that PL significantly enhanced oxaliplatin-induced growth inhibition in both gastric and colon cancer cells. Moreover, we found that PL potentiated the antitumor effect of oxaliplatin by inhibiting TrxR1 activity. PL combined with oxaliplatin markedly suppressed the activity of TrxR1, resulting in the accumulation of ROS and, thereby, DNA damage induction and p38 and JNK signaling pathway activation. Pretreatment with antioxidant N-acetyl-L-cysteine (NAC) significantly abrogated the combined treatment-induced ROS generation, DNA damage and apoptosis. Importantly, we found that activation of the p38 and JNK signaling pathways prompted by PL and oxaliplatin was also reversed by NAC pretreatment. In vivo, we found that PL combined with oxaliplatin significantly suppressed tumor growth in a gastric cancer xenograft model, and effectively reduced the activity of TrxR1 in tumor tissues. Remarkably, we found that PL attenuated body weight loss evoked by oxaliplatin treatment. Our data support a synergistic effect of PL and oxaliplatin and suggest that application of its combination may be more effective for the treatment of gastric cancer than oxaliplatin alone.

EBV-miR-BARTs exhibit significant relevance in epithelial tumors, particularly in EBV-associated gastric and nasopharyngeal cancers. However, their specific mechanisms in the initiation and progression of gastric cancer remain insufficiently explored. Initially, EBV-miRNA-BART6-5p and its target gene SMAD4 expression were assessed in EBV-associated gastric cancer tissues and cell lines. Subsequent transfection induced overexpression of EBV-miRNA-BART6-5p in AGS and MKN-45, and downregulation in EBV-positive cells (SUN-719). The subsequent evaluation aimed to observe their impact on gastric cancer cell proliferation, migration, and glycolytic processes, with the TGF-β/SMAD4 signaling pathway value clarified using a TGF-β inhibitor. EBV-miRNA-BART6-5p exhibits pronounced upregulation in EBV-associated gastric cancer tissues and EBV-positive cells, while its target gene SMAD4 demonstrates downregulated expression. Upregulation of it can promote the proliferation and migration of gastric cancer cells. Additionally, We found EBV-miRNA-BART6-5p promotes glycolysis of gastric cancer cells. Inhibition of the TGF-β/SMAD4 signaling pathway resulted in suppressed proliferation and migration of gastric cancer cells, concomitant with a diminished glycolytic capacity. In this study, we found that EBV-miRNA-BART6-5p can target SMAD4, effectively increasing glycolysis in gastric cancer cells by regulating the TGF-β/SMAD4 signaling pathway, thereby enhancing the proliferation and metastasis of gastric cancer cells. Our findings may offer new insights into the metabolic aspects of gastric cancer.

In recent years, with the development of nanotechnology, the use of various metal nanoparticles has become widespread specifically in the treatment of cancer. Furthermore, the application of silver nanoparticles (AgNPs) should not be denied in this respect. AgNPs hold great potential in the field of cancer biology and because of their anti-microbial activities they are vastly used in diverse clinical applications. AgNPs possess some physical and chemical features including heterogeneity in size, shape, and capping material. Moreover, their novel cytotoxic characteristics against mammalian cells makes them more applicable in tumor therapy and acting as anti-cancer agents. AgNPs have great potential in tumor diagnosis as well as treatment (Zhao et al., 2022; Păduraru et al., 2022; Patil et al., 2021). Gastric cancer is the fifth most common cancer with more than 1 million people newly diagnosed worldwide each year. Despite its worldwide decline in incidence and mortality over the past 5 decades, gastric cancer remains the third leading cause of cancer-related death (Sexton et al., 2020; Thrift and El-Serag, 2020) Gastric cancer is diagnosed histologically after endoscopic biopsy and staged using CT, endoscopic ultrasound, PET, and laparoscopy. The main treatment for early gastric cancer is endoscopic resection. Non-early operable gastric cancer is treated with surgery, which should include D2 lymphadenectomy (including lymph node stations in the perigastric mesentery and along the celiac arterial branches). Perioperative or adjuvant chemotherapy improves survival in patients with stage 1B or higher cancers. Advanced gastric cancer is treated with sequential lines of chemotherapy, starting with a platinum and fluoropyrimidine doublet in the first line; median survival is less than 1 year. Metastatic gastric cancer remains a non-curative disease. Palliative chemotherapy has been demonstrated to prolong survival without quality of life compromise. Many single-agents and combinations have been confirmed to be active in the treatment of metastatic disease. In the setting of metastatic or inoperable gastric cancer, the current evidence shows that chemotherapy improves survival in comparison to best supportive care and that combination chemotherapy is superior to monotherapy in terms of survival, response rate and symptom control. Although there are no internationally accepted standard regimens, in Europe, ECF (epirubicin, cisplatin, fluorouracil) has been considered the reference regimen; in the US cisplatin-fluoropyrimidine combinations are mainly used, while in Japan, cisplatin with S1 has become the standard. It has also been suggested that immunochemotherapy may improve survival of patients with curatively resected gastric cancer. Targeted therapies licensed to treat gastric cancer include trastuzumab (HER2-positive patients first line), ramucirumab (anti-angiogenic second line), and nivolumab or pembrolizumab (anti-PD-1 third line). Gastrointestinal symptoms are the most notable side effects of chemotherapeutic drugs (Kim et al., 2013; Janunger et al., 2001; Choi et al., 2018; Sastre et al., 2006; Zhou et al., 2017). Many recent studies have shown that green synthesized silver nanoparticles (AgNPs) can have cytotoxic effects on different cancer cells (Yesilot and Aydin, 2019). The biosynthesized AgNPs using the leaves extracts of Hemichroa pentandra showed considerable antioxidant activity and excellent anti-cancer activity against breast cancer cells (Punathil, 2018). Biosynthesized AgNPs from the leaf extract of Ochradenus arabicus can have suppressive effects against the human breast cancer cells (Al-kawmani et al., 2020). Also, green synthesized silver nanoparticles using Teucrium polium leaf extract exhibited significant anticancer activity against MNK45 human gastric cancer cell line (Hashemi et al., 2020). In this study we investigated the cytotoxic effects of green synthesized AgCl2 nanoparticles on gastric cancer (AGS) cells. Onopordum acanthium extract was used to synthesize AgCl2 nanoparticles. Onopordum acanthium has been applied traditionally as bactericide and antitumor agent (Al-Snafi, 2020). Gastric cancer cells were purchased from Pasteur Institute of Iran and cultured in growth medium until they reached 80-90% confluence. The cells were then treated with different concentrations (1.5625, 3.125, 6.25, 12.5, 25 and 50 μg/ml) of AgCl2 nanoparticle for 24 hours. The cytotoxic effect of AgCl2 nanoparticles was assessed using MTT assay method. The results showed that viability of AGS cells did not significantly change 24 hours after treatment with 1.5625 μg/ml of green synthesized AgCl2 nanoparticles compared to the control group; However, the viability in AGS cells significantly decreased when treated with 3.125, 6.25, 12.5, 25 and 50 μg/ml of green synthesized AgCl2 nanoparticles compared to control group. There cytotoxic effect was more in groups treated with 6.25, 12.5, and 25 than groups treated with 3.125, 6.25, and 12.5 μg/ml of green synthesized AgCl2, respectively. There was not significant difference between cell viability of group treated with 25 and 50 μg/ml of green synthesized AgCl2.Conclusion: Our results show that green synthesized AgCl2 nanoparticles have cytotoxic effects against gastric cancer (AGS) cells in vitro.

Recently, microRNA-665 (miR-665) has been reported to function as both tumour suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer, and lung cancer. However, the biological function of miR-665 and its precise mechanisms in gastric cancer (GC) have not been well clarified. The aim of this study was to study the roles of miR-665/PPP2R2A axis in GC. The levels of PPP2R2A and miR-665 were detected by quantitative PCR assay in GC tissues and cell lines. Moreover, the biological roles of miR-665 and PPP2R2A in GC cells were assessed by cell proliferation, invasion, and epithelial-mesenchymal transition (EMT). The mRNA and protein levels of PPP2R2A were determined by using quantitative PCR and Western blotting assays. Luciferase assays were used to confirm that PPP2R2A was one target of miR-665. In this study, the miR-665 level was dramatically reduced in GC tissues and cell lines, and the PPP2R2A expression was significantly enhanced. What is more, the PPP2R2A expression was negatively related to the miR-665 level in GC tissues. Furthermore, up-regulation of miR-665 obviously restrained GC cells proliferation, invasion, and EMT. We confirmed that miR-665 could directly target PPP2R2A by luciferase reporter assay. Besides, knockdown of PPP2R2A also could markedly inhibit the proliferation, invasion and EMT of GC cells. Finally, overexpression of miR-665 in GC cells partially reversed the promoted effects of PPP2R2A up-regulation. Overexpression of miR-665 restrained GC cells proliferation, invasion and EMT via regulation of PPP2R2A. SIGNIFICANCE OF THE STUDY: miR-665 has been reported to function as oncogene or tumour suppressor in different cancers. However, the precise roles of miR-665 in GC have not been elucidated. Our study for the first time demonstrated that miR-665 level was significantly down-regulated in GC. Additionally, miR-665 overexpression inhibited cell growth, invasion, and EMT of GC. Moreover, our data suggested a significant negative correlation between miR-665 and PPP2R2A expression in GC. MiR-665 suppressed GC cell proliferation, invasion, and EMT by directly targeting PPP2R2A, which suggested important roles for miR-665/PPP2R2A axis in the GC pathogenesis and its potential application in cancer therapy.

Background: Abnormal cell cycle progression is a characteristic of cancer, and targeting the cell cycle is a strategy for cancer treatment. TCGA reported that 7% and 12% of gastric cancers exhibit CCND1 or CCNE1 alterations, respectively. Besides, Cyclin D1 is overexpressed in 25% to 60% of invasive breast carcinomas, and gene amplification is observed in 10% to 30% of breast cancer cases. Furthermore, CDK4/6 and CDNK2A/B aberrations are frequently observed in gastric (39.6%) and breast (7.6%) cancers. The presence of such abnormalities in cell cycle-related molecules suggests that gastric and breast cancers are good candidates for treatment with cell cycle inhibitors. Palbociclib is a specific inhibitor of CDK4/6, a vital regulator of the G1 checkpoint, and has been approved by the FDA because it provided a significant benefit by extending PFS in a phase III trial for hormone-positive advanced breast cancer. However, the predictive marker of palbociclib is not determined. Even though CDKN2A loss has been considered as a sensitive marker of palbociclib, there is no preclinical evidence to support whether CDKN2A deficient cancer shows sensitivity to palbociclib, especially in gastric and breast cancer. Therefore, we investigated the effects of palbociclib on CDKN2A loss gastric and breast cancer cell lines as well as patient derived-xenograft (PDX) models. Methods: The cytotoxic assay, cell cycle analysis, and western blotting were conducted to determine the anti-tumor effect and action mechanisms of palbociclib on gastric and breast cancer cell lines. Moreover, modulation of CDKN2A expression was conducted by siRNA and plasmid overexpression. These in vitro data were validated in vivo model and gastric cancer PDX models which have CDKN2A loss as well. Results: There is a meaningful correlation between CDKN2A loss and palbociclib sensitivity among gastric and breast cancer cell lines. CDKN2A loss cells showed G1 cell cycle arrest by blocking Rb phosphorylation and inhibited proliferative cell signaling. Moreover, palbociclib promoted senescence rather than apoptosis. The depletion of CDKN2A expression using siRNA increased palbociclib sensitivity with G1 cell cycle arrest accompanied by senescence. In contrast, CDKN2A overexpression in sensitive cells showed insensitivity to palbociclib. The anti-tumor effects of palbociclib on CDKN2A loss breast cancer cells were validated in the xenograft model, and the two different gastric cancer PDX models have CDKN2A loss also showed a significant response to palbociclib as well. Conclusions: CDK4/6 inhibitor palbociclib showed an anti-tumor effect in vitro and in vivo xenograft model of CDKN2A loss gastric and breast cancer. Our results suggest that palbociclib has therapeutic potential for the treatment of not only breast cancer but also gastric cancer, not limited to a hormone-positive breast cancer type. Our results provide a rationale for the future clinical trials of palbociclib in the treatment of breast cancers. Citation Format: Ahrum Min, Yu Jin Kim, Miso Lee, Kyung-Hun Lee, Seock-Ah Im. CDKN2A loss can be a predictive marker of palbociclib in breast and gastric cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-40.

BackgroundIncreasing evidence suggests that microRNAs (miRNAs) play critical roles in cancer progression. Therefore, investigating the function of miRNAs that are aberrantly expressed in gastric cancer (GC) and characterizing the involved underlying mechanism are essential for the treatment of gastric cancer. MiR-138-5p was found to be down-regulated in multiple cancers, which acted as a tumor suppressor in cancer progression; however, whether and how miR-138-5p regulates the malignant behaviors of GC has not been fully understood.MethodsThe level of miR-138-5p in GC tissues and cell lines was detected by RT-qPCR. The effects of miR-138-5p on the growth of GC cells were evaluated by the in vitro Cell Counting Kit-8 (CCK-8) assay, cell apoptosis, cell cycle analysis, wound-healing assay, and in vivo xenograft mice model. The targets of miR-138-5p were predicted using the miRDB online tool, confirmed by luciferase report assay and Western blot.ResultsMiR-138-5p was frequently decreased in GC tissues and cell lines. Decreased expression of miR-138-5p was significantly associated with the lymph node metastasis of GC patients. Overexpression of miR-138-5p suppressed GC cell proliferation, migration, increased cell apoptosis as well as inhibited the tumor growth in vivo. DEK oncogene was predicted as a potential target of miR-138-5p. MiR-138-5p bound the 3ʹ-UTR of DEK and inhibited the level of DEK in GC cells. Restoration of DEK abrogated miR-138-5p overexpression-mediated suppression of GC cell proliferation and cell cycle arrest.ConclusionOur results demonstrated the anti-cancer role of miR-138-5p in GC by targeting DEK, which suggested miR-138-5p as a potential therapeutic target for the treatment of patient with GC.