Activity In Gastric Cancer Cells Research Articles

Helicobacter pylori infection induces POU5F1 upregulation and SPP1 activation to promote chemoresistance and T cell inactivation in gastric cancer cells

Infection with Helicobacter pylori (H. pylori or Hp) is associated with an increased susceptibility to gastric diseases, notably gastric cancer (GC). This study investigates the impact of Hp infection on chemoresistance and immune activity in GC cells. Hp infection in AGS and MKN-74 cells promoted proliferation, migration and invasion, apoptosis resistance, and tumorigenic activity of cells under cisplatin (DDP) plus gemcitabine (GEM) treatment. Additionally, it dampened activity of the co-cultured CD8+ T cells. Hp infection increased POU class 5 homeobox 1 (POU5F1) level, which further activated secreted phosphoprotein 1 (SPP1) transcription to increase its expression. Silencing of either SPP1 or POU5F1 enhanced the GEM sensitivity in GC cells, and it increased the populations of CD8+ T cells and the secretion of immune-active cytokines both in vitro and in xenograft tumors in immunocompetent mice. However, the effects of POU5F1 silencing were counteracted by SPP1 overexpression. Furthermore, the POU5F1/SPP1 axis activated the PI3K/AKT signaling pathway. This study demonstrates that Hp infection induces POU5F1 upregulation and SPP1 activation, leading to increased DDP/GEM resistance and T cell inactivation in GC cells.

Downregulation of lncRNA EPB41L4A-AS1 promotes gastric cancer cell proliferation, migration and invasion.

The incidence of gastric cancer ranks the first among digestive tract tumors in China. However, there are no specific symptoms in the early stage of the tumor and the diagnosis process is complex, so more effective detection methods are very needed. In this study, a novel long noncoding RNA (lncRNA) was introduced as a diagnostic biomarker for gastric cancer, which brought new thinking to the exploration of its pathological mechanism and clinical prediction. The level of lncRNA EPB41L4A-AS1 (EPB41L4A-AS1) in gastric cancer serum and cells was verified via real-time quantitative polymerase chain reaction (RT-qPCR). Receiver operating characteristic (ROC) curve was performed based on the EPB41L4A-AS1 level, and the diagnostic possibility of EPB41L4A-AS was analyzed. The chi-square test evaluated the correlation between EPB41L4A-AS expression and clinical information. The cells were cultured and transfected in vitro, and the mediations of abnormal EPB41L4A-AS level on the viability and motility of gastric cancer cells were verified through cell counting kit-8 (CCK-8) and Transwell assay. Furthermore, luciferase activity assay was performed to confirm the sponge molecule microRNA-17-5p (miR-17-5p) of EPB41L4A-AS1. EPB41L4A-AS1 was decreased in gastric cancer, and low EPB41L4A-AS1 level indicated resultful diagnostic value. Overexpression of EPB41L4A-AS1 inhibited the activity of gastric cancer cells, while knockdown of EPB41L4A-AS1 promoted tumor deterioration. EPB41L4A-AS1 directly targeted and regulated the expression ofmiR-17-5p. This study elaborated that EPB41L4A-AS1 is lowly expressed in gastric cancer. Silencing EPB41L4A-AS1 was beneficial to cell proliferation, migration, and invasion. EPB41L4A-AS1 provides a new possibility for the diagnosis of gastric cancer patients by targeting miR-17-5p.

MiRNA-383-5p Regulated Migration and Invasion of Tumor Cells by Inhibiting NCKAP1 Expression in Gastric Cancer.

Gastric cancer (GC) is the second deadliest disease in Asia, so it is crucial to find its promising therapeutic targets. The expression profile data of miR383-5p in the Cancer Genome Atlas (TCGA) were analyzed. The expression levels of miR383-5p in the collected clinical tissue samples and peripheral blood samples were examined by qPCR, and the relationship between its expression and the clinical data of patients was evaluated. MiR383-5p was overexpressed in the AGS cells, and cell biology assays, such as Transwell, were performed to detect the cell proliferation, migration, invasion and other cell biology abilities of miR383-5p. Target prediction and dual luciferase reporter gene assay were performed to find and validate the target genes of miR383-5p. The expression and activity of MMP and related proteins after overexpression of miR383-5p and NCKAP1 were detected by WB and gelatin zymography assay. The expression of miR383-5p was down-regulated in GC tissues, and its low expression was associated with lymph node metastasis. Restoration of miR383-5p expression in GC cells can inhibit the invasion and migration abilities of GC cells. MiR383-5p negatively regulated NCKAP1 through direct interaction with the 3'UTR sequence of NCKAP1. The overexpression of NCKAP1 can improve the migration and invasion abilities of GC cells, whereas overexpression of miR383-5p can inhibit growth of the aforementioned abilities of GC cells induced by NCKAP1 overexpression. The overexpression of NCKAP1 can increase the expression level and activity of MMP2, while the overexpression of miR383-5p can inhibit the increase of MMP2 expression level and activity in GC cells induced by NCKAP1 overexpression. NCKAP1 is a target gene of miR383-5p, and miR383-5p could be a valuable therapeutic target for stomach adenocarcinoma.

Quercetin Promotes Apoptosis of Gastric Cancer Cells through the EGFR-ERK Signaling Pathway

Previous studies have shown that various active components of licorice have anticancer effects. However, few studies have investigated the mechanism of action of licorice in gastric cancer. The effect of active compounds in licorice on the biological activity of gastric cancer cells was investigated in vitro (MKN-45 cells). Network pharmacology and molecular docking were used to predict the potential targets of licorice against gastric cancer and verify the binding stability of target proteins to compounds. In addition, the anticancer effect of licorice was assessed using a mouse model of gastric cancer. The licorice-active component (quercetin) effectively inhibited proliferation, caused cell cycle arrest, and promoted apoptosis in MKN-45 cells, accompanied by increased Cyt-C, decreased BCL-2, and decreased mitochondrial membrane potential and mitochondrial damage. Further research showed that quercetin targeted EGFR, blocked the ERK signaling pathway, and downregulated PTGS2. In the in vivo experiment, quercetin treatment resulted in reduced tumor volume, decreased Ki67 and BCL-2 expression in tumor tissue, increased caspase 3 and BAX levels, and induced mitochondrial damage.

Influence of Oxa-Nano-Liposome on the Drug Resistance of Gastric Cancer Cells Under p53-Mediated Autophagy

The influence of oxaliplatin (Oxa)-nano-liposomes on the drug resistance of gastric cancer cells (GCCs) and the role of p53-mediated autophagy in this process were investigated in this research. Oxa-nano-liposomes were prepared and their quality was evaluated. GCCs treated with Oxa-nano-liposomes were selected and rolled into a negative control (NC) group (cells+ culture medium), a positive control (PC) group (standard Oxa-nano-liposome), and a Oxa-nano-liposome sample group. Cell inhibition rates (IRs) at changeable drug concentrations (DCs) were compared and analyzed. Furthermore, levels of p53 and autophagy-related proteins (ARPs) (such as LC3-II and p62) in the cells were assessed using Western blotting. The results indicated that Oxa-nano-liposomes prepared (Oxa):natural soy phospholipids (NSP):cholesterol:polyethylene glycol (PEG) 2000 = 1:2:1:1 exhibited the best performance. The Oxa-nano-liposome sample group exhibited a higher cell IR to the NC group, showing a great difference (P <0.05). Additionally, the Oxa-nano-liposome sample group demonstrated superior efficacy compared to the PC group. With increasing DC, p53 and LC3-II were upshifted, while p62 was downshifted. In conclusion, Oxa-nano-liposomes effectively inhibited the growth of GCCs, exhibited improved efficacy, and contributed to reducing drug resistance in GCCs towards Oxa-nano-liposomes. Therefore, the Oxa-nano-Liposomes hold significant potential for clinical application. Moreover, p53 regulated the cellular autophagy, enhancing autophagic activity of GCCs.

YY1 is regulated by ALKBH5-mediated m6A modification and promotes autophagy and cancer progression through targeting ATG4B.

YY1 affects tumorigenesis and metastasis in multiple ways. However, the function of YY1 and the potential mechanisms through which it operates in gastric cancer (GC) progression by regulating autophagy remains poorly understood. This study aimed to assess the essential transcription factors (TFs) involved in autophagy regulation in GC. Western blot, RFP-GFP-LC3 double fluorescence and transmission electron microscopy (TEM) assays were used to probe autophagy activity in GC cells. Methylated RNA immunoprecipitation (MeRIP) was utilized to evaluate the ALKBH5-regulated m6A levels of YY1. Gain- and loss-of-function assays were employed in the scrutiny of the biological effects of the ALKBH5/YY1/ATG4B axis on cancer cell proliferation and invasion abilities in vitro. Per the findings, YY1 was identified as a crucial transcriptional activator of cancer autophagy-related genes and promoted the proliferation and aggressiveness of cancer cells associated with enhanced ATG4B-mediated autophagy. However, ectopic ALKBH5 expression abolished the YY1-induced effect via m6A modification. Importantly, YTHDF1 facilitated the mRNA stability of YY1 through m6A recognition. Collectively, this study found that YY1 was regulated by ALKBH5 and YTHDF1-mediated m6A modification and served as an autophagy-dependent tumor driver to accelerate cancer progression through ATG4B transactivation, providing an exploitable therapeutic target for GC.

DNMT1 expression partially dictates 5-Azacytidine sensitivity and correlates with RAS/MEK/ERK activity in gastric cancer cells

ABSTRACT Though DNMTs inhibitors were widely used in myelodysplastic syndrome and leukaemia, their application in solid tumours has been limited by low response rate and lack of optimal combination strategies. In gastric cancer (GC), the therapeutic implication of KRAS mutation or MEK/ERK activation for combinational use of DNMTs inhibitors with MEK/ERK inhibitors remains elusive. In this study, stable knockdown of DNMT1 expression by lentiviral transfection led to decreased sensitivity of GC cells to 5-Azacytidine. KRAS knockdown in KRAS mutant GC cells or the MEK/ERK activation by EGF stimulation in GC cells increased DNMT1 expression, while inhibition of MEK/ERK activity by Selumetinib led to decreased DNMT1 expression. 5-Azacytidine treatment, which led to dramatic decline of DNMTs protein levels and increased activity of MEK/ERK pathway, altered the activity of MEK/ERK inhibitor Selumetinib on GC cells. Both RAS-dependent gene expression signature and expression levels of multiple MEK/ERK-dependent genes were correlated with DNMT1 expression in TCGA stomach cancer samples. In conclusion, DNMT1 expression partially dictates 5-Azacytidine sensitivity and correlates with RAS/MEK/ERK activity in GC cells. Combining DNMTs inhibitor with MEK/ERK inhibitor might be a promising strategy for patients with GC.

Diosmetin inhibits the growth and invasion of gastric cancer by interfering with M2 phenotype macrophage polarization.

Overturning M2 phenotype macrophage polarization is a promising therapeutic strategy for gastric cancer (GC). Diosmetin (DIO) is a natural flavonoid with antitumor effect. The aim of this study was to investigate the effect of DIO on polarization of M2 phenotype macrophages in GC. THP-1 cells were induced to M2 phenotype macrophages and co-cultured with AGS cells. The effects of DIO were determined by flow cytometry, qRT-PCR, CCK-8, Transwell, and western blot. To explore the mechanisms, THP-1 cells were transfected with adenoviral vectors containing tumor necrosis factor receptor-associated factor 2 (TRAF2) or si-TRAF2. DIO (0, 5, 10, and 20 μM) restrained the M2 phenotype macrophage polarization. In addition, DIO (20 μM) reversed the increased viability and invasion of AGS cells induced by the co-culture of M2 macrophages. Mechanistically, TRAF2 knockdown inhibited the effect of M2 phenotype macrophages on AGS cells'growth and invasion. Furthermore, DIO (20 μM) was found to decrease TRAF2/NF-κB activity in GC cells. However, TRAF2 overexpressed reversed the inhibitory effect of DIO on the co-culture system. The in vivo study confirmed that DIO treatment (50 mg/kg) could repress the growth of GC. DIO treatment markedly reduced the expressions of Ki-67 and N-cadherin, and decreased the protein levels of TRAF2 and p-NF-κB/NF-κB. In conclusion, DIO inhibited the growth and invasion of GC cells by interfering with M2 phenotype macrophage polarization through repression of the TRAF2/NF-κB signaling pathway.

Palmitic acid combined with γ-interferon inhibits gastric cancer progression by modulating tumor-associated macrophages' polarization via the TLR4 pathway.

Tumor-associated macrophages (TAMs) constitute the main infiltrating immune cells in the solid tumor microenvironment. Amounting studies have analyzed the antitumor effect on immune response induced by Toll-like receptor (TLR) agonists, such as lipopolysaccharide (LPS), γ-interferon (γ-IFN), and palmitic Acid (PA). However, their combined treatment for gastric cancer (GC) has not been illuminated. We investigated the relevance of macrophage polarization and the effect of PA and γ-IFN in GC in vitro and in vivo. M1 and M2 macrophage-associated markers were measured by real-time quantitative PCR and flow cytometry, and the activation level of the TLR4 signaling pathways was evaluated by western blot analysis. The effect of PA and γ-IFN on the proliferation, migration, and invasion of GC cells (GCCs) was evaluated by Cell-Counting Kit-8, transwell assays, and wound-healing assays. In vivo animal models were used to verify the effect of PA and γ-IFN on tumor progression, and the M1 and M2 macrophage markers, CD8 + T lymphocytes, regulatory T cells (Treg) cells, and the myeloid-derived suppressor cells (MDSCs) in tumor tissues were analyzed by flow cytometry and immunohistochemical (IHC). The results showed that this combination strategy enhanced M1-like macrophages and diminished M2-like macrophages through the TLR4 signaling pathway in vitro. In addition, the combination strategy impairs the proliferative and migratory activity of GCC in vitro and in vivo. While, the antitumor effect was abolished using the TAK-424 (a specific TLR-4 signaling pathway inhibitor) in vitro. The combined treatment of PA and γ-IFN inhibited GC progression by modulating macrophages polarization via the TLR4 pathway.

Regulation of autophagy by non-coding RNAs in gastric cancer.

Autophagy is a conserved cellular self-digesting process that degrades obsoleting proteins and cellular components and plays a crucial role in the tumorigenesis, metastasis, and drug resistance of various tumors such as gastric cancer (GC). As a hotspot in molecular biology, non-coding RNAs (ncRNAs) are involved in the regulation of multiple biological processes, such as autophagy. Increasing evidence indicate that various ncRNAs exert double roles in the initiation and progression of GC, either serve as oncogenes or tumor suppressors. Recent studies have shown that some ncRNAs could modulate autophagy activity in GC cells, which would affect the malignant transformation and drug resistance. Whether the function of ncRNAs in GC is dependent on autophagy is undefined. Therefore, identifying the underlying moleculr targets of ncRNAs in autophagy pathways and the role of ncRNA-regulated autophagy in GC could develop new treatment interventions for this disease. This review summarizes the autophagy process and its role in GC, and the regulatory mechanisms of ncRNAs, as well as focuses on the dual role of ncRNAs-mediated autophagy in GC, for the development of potential therapeutic strategies in GC patients.

Peimine-induced apoptosis and inhibition of migration by regulating reactive oxygen species-mediated MAPK/STAT3/NF-κB and Wnt/β-catenin signaling pathways in gastric cancer MKN-45 cells.

Peimine (PM), a natural product extracted from Fritillaria, has anti-inflammatory, drug resistance reversal, and other pharmacological effects. The purpose of this study was to investigate the antitumor effects and the molecular mechanisms of PM using gastric cancer MKN-45 cells. Cell counting kit-8 assays were used to evaluate the viability of gastric cancer cells after treatment with PM. The results showed that PM significantly reduced the activity of gastric cancer cells, and the effect was most obvious in MKN-45 cells. Annexin V-FITC/propidium iodide staining and flow cytometry were used to assess apoptosis of MKN-45 cells after PM treatment. Our results showed that PM-induced apoptosis of MKN-45 cells. Flow cytometry was also used to determine the mitochondrial membrane potential and reactive oxygen species (ROS) levels, and to assess PM-induced cell-cycle arrest. Additionally, Western blot was used to analyze the expression of signaling pathway proteins and the relationship between apoptosis and ROS accumulation. Our findings showed that PM destroyed the mitochondria by diminishing the mitochondrial membrane potential. In addition, PM regulated the mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3, and nuclear factor kappa-B signaling pathways by promoting the accumulation of ROS in MKN-45 cells. PM also caused cell-cycle arrest in the G2/M phase by increasing ROS accumulation. Furthermore, PM inhibited cell migration by regulating the Wnt/β-catenin pathway. In conclusion, PM plays an anticancer role through endogenous apoptosis pathways and by inhibiting cell migration, and it has the potential to be a useful treatment for gastric cancers.

S3I-201 derivative incorporating naphthoquinone unit as effective STAT3 inhibitors: Design, synthesis and anti-gastric cancer evaluation

Signal transducer and activator of transcription 3 (STAT3) is a key regulator of many human cancers and has been widely recognized as a promising target for cancer therapy. A variety of small-molecule inhibitors have been developed for targeting STAT3, and some of them are now undergoing clinical trials. S3I-201, a known STAT3 inhibitor, may block STAT3 function in cancer cells by binding to the STAT3 SH2 domain to disrupt STAT3 protein complex formation. Using S3I-201 as a starting point for drug development, we synthesized a series of new STAT3 inhibitors 9a-x in this study by introducing naphthoquinone unit, a privileged fragment in STAT3 inhibitors. Most of the compounds exhibited strong anti-proliferation activity of gastric cancer cells (MGC803, MKN28, MNK1, and AGS). The representative compound 9n (SIL-14) could effectively inhibit the colony formation and migration of gastric cancer cells MGC803, arrest the cell cycle and induce MGC803 cell apoptosis at low micromolar concentrations in vitro. In addition, SIL-14 can also inhibit the phosphorylation of STAT3 protein and significantly decrease the expression of total STAT3, suggesting that it may exert anticancer effects by blocking the STAT3 signaling pathway. These results support that SIL-14 may be a promising STAT3 inhibitor for the further development of potential anti-gastric cancer candidates.

Polysaccharide from Spirulina platensis Evokes Antitumor Activity in Gastric Cancer Cells via Modulation of Galectin-3 and Exhibited Cyto/DNA Protection: Structure-Function Study.

Polysaccharides play significant role in the management of different cancer types including gastric cancer. Here, we report the effect of spirulina polysaccharide (Sp) on galectin-3 modulatory activity in gastric cancer cells (AGS). The isolated Sp possessed an average molecular weight of 1457 kDa and galactose (42%) as a major sugar consisting of (β1-4d) units with a galactoarabinorhamnoglycan backbone. The Sp inhibited the proliferation of AGS cells by 48% without affecting normal NIH/3T3 cells as compared to doxorubicin, a known anticancer drug. Also, Sp exhibited significant (p < 0.05) galectin-3 mediated hemeagglutination inhibition with MIC of 9.37 μg/mL compared to galactose (6.25 μg/mL), a sugar specific to galectin-3. Galactose showed the highest molecular interaction with galectin-3 in the in silico study. In addition, Sp exhibited the cytoprotection in RBCs, buccal cells, and DNA exposed to oxidants. These findings suggest that Sp offers a promising therapeutic tool in the management of gastric cancer.

RhoGDI2-Mediated Rac1 Recruitment to Filamin A Enhances Rac1 Activity and Promotes Invasive Abilities of Gastric Cancer Cells.

Simple SummaryRho GDP dissociation inhibitor 2 (RhoGDI2), a regulator of Rho family GTPase, has been known to promote tumor growth and malignant progression by activating Rac1 in gastric cancer. However, the precise molecular mechanism by which RhoGDI2 activates Rac1 in gastric cancer cells remains unclear. In this study, we found that interaction between RhoGDI2 and Rac1 is a prerequisite for the recruitment of Rac1 to Filamin A. Moreover, we found that Filamin A acts as a scaffold protein that mediates Rac1 activation. Furthermore, we found that Trio, a Rac1-specific GEF, is critical for Rac1 activation in gastric cancer cells. Conclusively, RhoGDI2 increases Rac1 activity by recruiting Rac1 to Filamin A and enhancing the interaction between Rac1 and Trio, which is critical for invasive ability of gastric cancer cells. Our findings suggest that RhoGDI2 might be a potential therapeutic target for reducing gastric cancer cell metastasis.Rho GDP dissociation inhibitor 2 (RhoGDI2), a regulator of Rho family GTPase, has been known to promote tumor growth and malignant progression in gastric cancer. We previously showed that RhoGDI2 positively regulates Rac1 activity and Rac1 activation is critical for RhoGDI2-induced gastric cancer cell invasion. In this study, to identify the precise molecular mechanism by which RhoGDI2 activates Rac1 activity, we performed two-hybrid screenings using yeast and found that RhoGDI2 plays an important role in the interaction between Rac1, Filamin A and Rac1 activation in gastric cancer cells. Moreover, we found that Filamin A is required for Rac1 activation and the invasive ability of gastric cancer cells. Depletion of Filamin A expression markedly reduced Rac1 activity in RhoGDI2-expressing gastric cancer cells. The migration and invasion ability of RhoGDI2-expressing gastric cancer cells also substantially decreased when Filamin A expression was depleted. Furthermore, we found that Trio, a Rac1-specific guanine nucleotide exchange factor (GEF), is critical for Rac1 activation and the invasive ability of gastric cancer cells. Therefore, we conclude that RhoGDI2 increases Rac1 activity by recruiting Rac1 to Filamin A and enhancing the interaction between Rac1 and Trio, which is critical for the invasive ability of gastric cancer cells.

Discovery of the antitumor activities of a potent DCN1 inhibitor compound 383 targeting LSD1 in gastric cancer

Dual target compounds have become a hot spot in the treatment of cancer in recent years. Histone lysine specific demethylase 1 (LSD1) is identified as histone demethylase and acts as a key regulator involved in many other cellular activities through its demethylation function. We have reported a triazolo [1,5-α] pyrimidine-based DCN1(defective in cullin neddylation protein 1) inhibitor compound 383 (IC50 = 11 nM) which could selectively inhibit Cullin 3/1 neddylation in MGC-803 cells. In this research, we investigated that compound 383 could target LSD1 and inhibit the biological function of LSD1 in MGC-803 cells (IC50 = 0.53 μM). We found that compound 383 could induce the degradation of LSD1 and inhibit MGC-803 cell proliferation, migration and invasion in a dose-dependent manner. Compound 383 could cause cell cycle arrest at G2/M phase by down-regulating the expression of LSD1. In addition, compound 383 could significantly reverse epithelial-mesenchymal transition (EMT) through increase H3K4me methylation at E-cadherin promotor. Furthermore, the in vivo inhibitory effect of compound 383 without obvious toxicity was confirmed in nude mouse transplanted MGC-803 tumor cells model. Collectively, these results suggest that the DCN1 inhibitor compound 383 exhibits antiproliferative activity in gastric cancer cells by targeting LSD1 which promotes compound 383 as a good starting point for the development of dual-target therapeutics for gastric cancer.

Sijunzi Decoction Inhibits Stemness by Suppressing β-Catenin Transcriptional Activity in Gastric Cancer Cells.

To investigate a previously uncharacterized function of Sijunzi Decoction (SJZD) in inhibition of gastric cancer stem cells (GCSCs). MKN74 and MKN45, two CD44 positive gastric cancer cell lines with stem cell properties were used. The cells were divided into 2 groups. Treatment group was treated with SJZD (1-5 mg/mL) for indicated time (48 h-14 days). The control group was treated with equal volume of phosphate buffered saline. Cell Counting Assay Kit-8 were used to measure cell viability. Spheroid colony formation and GCSCs marker expression were performed to determine GCSCs stemness. Cell fractionation and chromatin immunoprecipitation assays were used to assess the distribution and DNA-binding activity of β-catenin after SJZD treatment, respectively. SJZD treatment repressed cell growth and induced apoptosis in MKN74 and MKN45 cell lines (P<0.05). Moreover, SJZD dramatically inhibited formation of spheroid colony and expression of GCSC markers in GC cells (P<0.05). Mechanistically, SJZD reduced nuclear accumulation and DNA binding activity of β-catenin (P<0.05), the key regulator for maintaining CSC stemness. SJZD inhibits GCSCs by attenuating the transcriptional activity of β-catenin.

LncRNA CCAT1 Upregulates ATG5 to Enhance Autophagy and Promote Gastric Cancer Development by Absorbing miR-140-3p.

Long noncoding RNA colon cancer-associated transcript 1 (LncRNA CCAT1) is highly expressed in gastric cancer tissues and plays a role in autophagy. However, the underlying mechanism still needs to be further clarified. To study the role of LncRNA CCAT1 in regulating autophagy of gastric cancer cells, analyze its downstream targets, and elucidate the mechanism. qPCR detected the expression of LncRNA CCAT1 in gastric cancer cells. The proliferation, migration, and invasion ability of LncRNA CCAT1 and the expression level of autophagy-related proteins in gastric cancer cells were detected. Bioinformatics method predicted the downstream targets of LncRNA CCAT1, and they were verified by dual-luciferase assay. The relationship between LncRNA CCAT1, miR-140, and ATG5 was verified by co-transfection, and the expression levels of ATG5 and ATG5-ATG12 complex proteins were detected. Finally, the role of LncRNA CCAT1 in vivo was confirmed by gastric cancer transplantation model. LncRNA CCAT1 was highly expressed in gastric cancer cells. LncRNA CCAT1 can promote the proliferation, migration, invasion, and autophagy activity of gastric cancer cells. LncRNA CCAT1 can bind to miR-140-3p and regulate its expression, while miR-140-3p further regulates the expression of ATG5. Overexpression of LncRNA CCAT1 can promote tumor growth in nude mice. After LncRNA CCAT1 silencing, the positive expression rate of ATG5 in nude mice was low. LncRNA CCAT1 may inhibit the expression of miR-140-3p by sponge adsorption, thus weakening its inhibitory effect on ATG5. Eventually, gastric cancer cells were more prone to autophagy under the pressure of stress.

RETRACTED ARTICLE: Ethaselen synergizes with oxaliplatin in tumor growth inhibition by inducing ROS production and inhibiting TrxR1 activity in gastric cancer

BackgroundOxaliplatin is one of the most commonly used chemotherapeutic agent for 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. Hence, it is of great significance to develop novel therapies to potentiate the anti-tumor effect and reduce the toxicity of oxaliplatin. In our previous study, we demonstrated that ethaselen (BBSKE), an inhibitor of thioredoxin reductase, effectively inhibited the growth of gastric cancer cells and promoted apoptosis in vitro. In the present study, we investigated whether BBSKE can potentiate the anti-tumor effect of oxaliplatin in gastric cancer in vivo and vitro.MethodsCellular apoptosis and ROS levels were analyzed by flow cytometry. Thioredoxin reductase 1 (TrxR1) activity in gastric cancer cells, organoid and tumor tissues was determined by using the endpoint insulin reduction assay. Western blot was used to analyze the expressions of the indicated proteins. Nude mice xenograft models were used to test the effects of BBSKE and oxaliplatin combinations on gastric cancer cell growth in vivo. In addition, we also used the combined treatment of BBSKE and oxaliplatin in three cases of gastric cancer Patient-Derived organoid (GC-PDO) to detect the anti-tumor effect.ResultsWe found that BBSKE significantly enhanced oxaliplatin-induced growth inhibition in gastric cancer cells by inhibiting TrxR1 activity. Because of the inhibition of TrxR1 activity, BBSKE synergized with oxaliplatin to enhance the production of ROS and activate p38 and JNK signaling pathways which eventually induced apoptosis of gastric cancer cells. In vivo, we also found that BBSKE synergized with oxaliplatin to suppress the gastric cancer tumor growth in xenograft nude mice model, accompanied by the reduced TrxR1 activity. Remarkably, we found that BBSKE attenuated body weight loss evoked by oxaliplatin treatment. We also used three cases of GC-PDO and found that the combined treatment of BBSKE and oxaliplatin dramatically inhibited the growth and viability of GC-PDO with increased ROS level, decreased TrxR1 activity and enhanced apoptosis.ConclusionsThis study elucidates the underlying mechanisms of synergistic effect of BBSKE and oxaliplatin, and suggests that the combined treatment has potential value in gastric cancer therapy.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13046-021-02052-z.

Antitumor Effects of Paeoniflorin on Hippo Signaling Pathway in Gastric Cancer Cells.

Background Paeoniflorin has been reported to exert antitumor effects on human cancers. However, the role of paeoniflorin in gastric cancer and the underlying molecular mechanism are unelucidated. Therefore, we determined whether paeoniflorin could exhibit anticancer activity in gastric cancer cells. Methods MTT was used to measure the viability of cells after paeoniflorin treatment. FACS was performed to examine cell apoptosis. Wound healing and transwell invasion assays were conducted to examine cell migratory and invasive activities. Western blotting was used to explore the mechanism by which paeoniflorin exerted tumor suppressive effects. Results We found that paeoniflorin suppressed cell growth, enhanced apoptosis, and reduced cell invasion. Notably, we showed that paeoniflorin inhibited the expression of TAZ in gastric cancer cells. The overexpression of TAZ abrogated the antitumor activity of paeoniflorin in gastric cancer cells. In contrast, the downregulation of TAZ promoted the tumor suppressive effects of paeoniflorin treatment. Conclusion Hence, targeting TAZ with paeoniflorin could be a novel approach for the treatment of human gastric cancer.

Anticancer Effects of Helminthostachys zeylanica Ethyl acetate Extracts on Human Gastric Cancer Cells through Downregulation of the TNF-α-activated COX-2-cPLA2-PGE2 Pathway.

Background: Gastric cancer (GC) is the second most prevalent cancer worldwide and the eighth most common cause of tumor-related death in Taiwan. Helminthostachys zeylanica, a flavonoid compound, has anti-inflammatory, immunomodulatory, and anticancer effects. We examined whether an extract of H. zeylanica (E1 and E2) has potential as a treatment for GC.Methods: We investigated the effects (pro-apoptosis, pro-autophagy, and antiproliferation ability) of H. zeylanica-E2 on cell viability in healthy gastric epithelial (GES-1) and GC cells (AGS and BGC823). H. zeylanica-E2 was toxic to GC cells but had little or no toxicity to normal cells.Results: In this study, H. zeylanica-E2 induced apoptosis through caspase 3/7, Bcl-2, Bax, cyclooxygenase-2 (COX-2), and cleaved poly (ADP-ribose) polymerase pathways in GC cells. In addition, it increased autophagy by stimulating autophagy-related protein (ATG)5, ATG7, LC3-I/LC3-II, and inhibiting COX-2 activity in GC cells. We also found that H. zeylanica-E2 exhibited antiproliferation ability through cell cycle arrest in G0/G1 and G2/M and suppressed the migration of GC cells. The anticancer effects of H. zeylanica-E2 in GC cells might be mediated partly through inhibition of tumor necrosis factor-α (TNF-α)-activated proinflammatory cytosolic phospholipase A2 (cPLA2)-COX-2-prostaglandin E2 (PGE2) pathway.Conclusions: Our results suggest that H. zeylanica-E2 has potential as a novel adjunctive agent for the treatment of GC.