BACKGROUND: The transcription factor POU2F1 regulates the expression levels of microRNAs in neoplasia. However, the miR-29b1/a cluster modulated by POU2F1 in gastric cancer (GC) remains unknown. METHODS: Gene expression in GC cells was evaluated using reverse-transcription polymerase chain reaction (PCR), western blotting, immunohistochemistry, and RNA in situ hybridization. Co-immunoprecipitation was performed to evaluate protein interactions. Transwell migration and invasion assays were performed to investigate the biological behavior of GC cells. MiR-29b1/a cluster promoter analysis and luciferase activity assay for the 3'-UTR study were performed in GC cells. In vivo tumor metastasis was evaluated in nude mice. RESULTS: POU2F1 is overexpressed in GC cell lines and binds to the miR-29b1/a cluster promoter. POU2F1 is upregulated, whereas mature miR-29b-3p and miR-29a-3p are downregulated in GC tissues. POU2F1 promotes GC metastasis by inhibiting miR-29b-3p or miR-29a-3p expression in vitro and in vivo . Furthermore, PIK3R1 and/or PIK3R3 are direct targets of miR-29b-3p and/or miR-29a-3p , and the ectopic expression of PIK3R1 or PIK3R3 reverses the suppressive effect of mature miR-29b-3p and/or miR-29a-3p on GC cell metastasis and invasion. Additionally, the interaction of PIK3R1 with PIK3R3 promotes migration and invasion, and miR-29b-3p , miR-29a-3p , PIK3R1 , and PIK3R3 regulate migration and invasion via the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway in GC cells. In addition, POU2F1 , PIK3R1 , and PIK3R3 expression levels negatively correlated with miR-29b-3p and miR-29a-3p expression levels in GC tissue samples. CONCLUSIONS The POU2F1 - miR-29b-3p / miR-29a-3p-PIK3R1 / PIK3R1 signaling axis regulates tumor progression and may be a promising therapeutic target for GC.
MicroRNAs/metabolism* ; Humans ; Stomach Neoplasms/pathology* ; Cell Line, Tumor ; Cell Movement/physiology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Animals ; Mice ; Octamer Transcription Factor-1/metabolism* ; Mice, Nude ; Class Ia Phosphatidylinositol 3-Kinase/metabolism* ; Neoplasm Invasiveness ; Gene Expression Regulation, Neoplastic/genetics* ; Male ; Immunohistochemistry ; Female

This study aims to investigate the pathogenesis of precancerous lesions of gastric cancer(PLGC) and explore the potential molecular mechanism of Weifuchun Capsules(WFC) in treating PLGC via the nuclear factor-κB(NF-κB)/NOD-like receptor protein 3(NLRP3) inflammasome signaling pathway. Ninety male SPF-grade Wistar rats were randomized into a normal feeding group and a modeling group. The normal feeding group received a regular diet, while the modeling group was subjected to the disease-syndrome combined modeling of PLGC. Specifically, the rats had free access to the water containing 120 μg·mL~(-1) N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and received a diet containing 0.05% ranitidine in an irregular feeding pattern(alternations between fasting and overfeeding). After 15 weeks, the rats in the normal feeding group were randomized into control, control-NF-κB activator betulinic acid(C-BA), and control-NF-κB inhibitor pyrrolidine dithiocarbamaten(C-PDTC) groups. Meanwhile, the rats in the modeling group continuously underwent the modeling procedure and were randomized into model, WFC, model-NF-κB activator(M-BA), and model-NF-κB inhibitor(M-PDTC) groups. The model group and control group were given aseptic water by intragastric administration, once a day. WFC was given at a dose(432 mg·kg~(-1)) 6 times the equivalent dose for adults(body weight: 60 kg) by gavage, once a day. The rats in the C-BA and M-BA groups were administrated with BA by intraperitoneal injection at a dose of 10 mg·kg~(-1), twice a week. The rats in the C-PDTC and M-PDTC groups were administrated with PDTC by intraperitoneal injection at a dose of 50 mg·kg~(-1), twice a week. The interventions were carried out for 4 weeks. Histopathological changes of the gastric mucosa were observed and scored by hematoxylin-eosin(HE) and alcian blue-periodic acid Sthiff(AB-PAS) staining. The levels of inflammatory cytokines including interleukin(IL)-1β, IL-6, IL-18, tumor necrosis factor-alpha(TNF-α), and IL-10 in the gastric tissue were determined by enzyme-linked immunosorbent assay(ELISA). The expression levels of proteins associated with the NF-κB/NLRP3 inflammasome in the gastric mucosa were determined by Western blot. The positive expression areas of proteins related to NF-κB/NLRP3 inflammasome in the gastric mucosa were measured by immunohistochemistry. The results showed that compared with the control group, the model, C-BA, and M-BA groups showed significantly risen scores of mucosal inflammation, degree of inflammatory activity, gland atrophy, and intestinal metaplasia, and the model and M-BA groups showed significanly risen scores of dysplasia. Compared with the model group, the WFC group demonstrated significantly declined scores of mucosal inflammation and degree of inflammatory activity, as well as declined scores of intestinal metaplasia and dysplasia. Compared with the control group, the model and C-BA groups showed significantly elevated levels of IL-1β, IL-6, IL-18, and TNF-α in the gastric tissue, and the model group showed significantly elevated level of IL-10. In addition, the model and C-BA groups showed significantly up-regulated expression of NF-κB p65, NLRP3, cysteine-aspartic acid protease 1(caspase-1), and apoptosis-associated speck-like protein containing a CARD(ASC) in the gastric mucosa and increased positive expression areas of NF-κB p65, NLRP3, and ASC. Compared with the model group, the WFC group showed significantly decreased levels of IL-1β, IL-6, IL-18, TNF-α, and IL-10 in the gastric tissue, and the M-PDTC group showed significantly lowered levels of IL-1β, IL-18, and TNF-α in the gastric mucosa. Both WFC and M-PDTC groups demonstrated significantly down-regulated expression levels of NF-κB p65, phosphorylated NF-κB p65(p-NF-κB p65), NLRP3, and caspase-1 in the gastric mucosa, along with significant decreases in the positive expression areas of NF-κB p65, NLRP3, and ASC. In conclusion, the pathogenesis of PLGC is closely related to the activation of the NF-κB/NLRP3 inflammasome signaling pathway. WFC can alleviate mucosal inflammation, inhibit glandular atrophy, partially reverse intestinal metaplasia, and reduce dysplasia to delay the process of inflammation-cancer transformation, and meanwhile it can effectively lower the levels of inflammatory cytokines and down-regulate the expression of pathway-related proteins in the stomach. Therefore, WFC may treat PLGC by inhibiting the NF-κB/NLRP3 inflammasome signaling pathway.
Animals ; Male ; NF-kappa B/genetics* ; Rats ; Rats, Wistar ; Drugs, Chinese Herbal/administration & dosage* ; Signal Transduction/drug effects* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Stomach Neoplasms/pathology* ; Inflammasomes/genetics* ; Humans ; Precancerous Conditions/metabolism* ; Capsules

This study aimed to investigate the effects of Zhiwei Fuwei Pills on mitochondrial apoptosis in the rat model of precancerous lesions of gastric cancer(PLGC) based on the microRNA-21(miRNA-21)/B-cell lymphoma-2(Bcl-2) signaling pathway. Eighty-five 5-week-old male SPF-grade SD rats were selected, of which 75 were fed with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) for multifactorial modeling, and the PLGC model was established after 26 weeks. The rats were randomly grouped as follows: model, folic acid(0.002 g·kg~(-1)), low-dose(0.42 g·kg~(-1)) Zhiwei Fuwei Pills, medium-dose(0.84 g·kg~(-1)) Zhiwei Fuwei Pills, and high-dose(1.67 g·kg~(-1)) Zhiwei Fuwei Pills, with 15 rats in each group. Additionally, 10 rats were assigned to a blank group and administrated with an equivalent volume of normal saline by gavage. After four weeks of continuous drug administration, the gastric mucosal tissue was collected. Hematoxylin-eosin(HE) staining was performed to reveal the pathological changes in the gastric mucosa. Terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) was employed to detect apoptosis in gastric mucosal epithelial cells. RT-PCR was adopted to determine the mRNA levels of miRNA-21, phosphatase and tensin homolog(PTEN), Bcl-2, Bcl-2-associated X protein(Bax), and cysteinyl aspartate-specific protease 3(caspase-3). Western blot was employed to determine the protein levels of PTEN, Bcl-2, Bax, and caspase-3. Immunohistochemistry(IHC) was used to detect the positive expression of PTEN, Bcl-2, and Bax in the gastric mucosal tissue. Transmission electron microscopy(TEM) was employed to observe the morphological and structural changes in mitochondria. The results showed that compared with model group, the drug administration groups showed alleviated pathological changes, with increased apoptotic cells, down-regulated mRNA levels of miRNA-21 and Bcl-2, up-regulated mRNA and protein levels of PTEN, Bax, and caspase-3, and down-regulated protein level of Bcl-2. In addition, the drug administration groups exhibited mitochondrial swelling and rupture and reduction of cristae, which indicated mitochondrial apoptosis. These findings suggest that Zhiwei Fuwei Pills can effectively improve mitochondrial apoptosis in PLGC cells by regulating the miRNA-21/Bcl-2 signaling pathway.
Animals ; MicroRNAs/metabolism* ; Male ; Apoptosis/drug effects* ; Stomach Neoplasms/physiopathology* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Rats ; Rats, Sprague-Dawley ; Drugs, Chinese Herbal/administration & dosage* ; Mitochondria/genetics* ; Signal Transduction/drug effects* ; Precancerous Conditions/drug therapy* ; Humans ; PTEN Phosphohydrolase/genetics*

Objective To investigate whether PLCB1 expression leads to gastric adenocarcinoma metastasis and poor prognosis, and to preliminarily analyze its mechanism. Methods 122 gastric adenocarcinoma patients and their adjacent non-cancerous tissues were selected, and tissue microarray technology was used to detect the expression levels of PLCB1, epithelial cadherin(E-cadherin), vimentin and CD8⁺ T cells by immunohistochemistry, and scored by two pathologists. According to the immunohistochemical score of PLCB1, the patients were divided into PLCB1 high expression group (IHC>90) and PLCB1 low expression group (IHC≤90). The clinical pathological characteristics, epithelial mesenchymal transition(EMT)-related proteins and CD8⁺ T cells expression differences between the two groups were compared. The overall survival of the patients was collected, and COX regression analysis and Kaplan-Meier curve were used to evaluate the relationship between PLCB1 expression level and prognosis. Results PLCB1 was highly expressed in 55 cases of gastric adenocarcinoma tissues, while only 12 cases in adjacent non-cancerous tissues. The tumor invasion depth, lymph node metastasis degree and TNM stage of the PLCB1 high expression group were higher than those of the PLCB1 low expression group. Chi-square test showed that PLCB1 expression level was negatively correlated with E-cadherin (r=-0.339), positively correlated with vimentin (r=0.211), and negatively correlated with CD8⁺ T cells (r=-0.343). Kaplan-Meier curve analysis showed that the overall survival and disease-free survival of gastric adenocarcinoma patients with high PLCB1 expression were significantly reduced. Multivariate COX regression analysis showed that except for lymph node metastasis, tumor invasion depth, TNM stage, E-cadherin and vimentin were also independent prognostic factors for gastric adenocarcinoma patients. Conclusion PLCB1 is highly expressed in gastric adenocarcinoma, and is closely related to tumor aggressiveness and prognosis. PLCB1 may induce EMT and inhibit CD8⁺ T cell infiltration to affect gastric adenocarcinoma metastasis and immune response.
Humans ; Stomach Neoplasms/genetics* ; Epithelial-Mesenchymal Transition ; Male ; Female ; Middle Aged ; Prognosis ; Adenocarcinoma/genetics* ; Cadherins/metabolism* ; Aged ; Adult ; CD8-Positive T-Lymphocytes/immunology* ; Vimentin/metabolism* ; Lymphatic Metastasis ; Neoplasm Metastasis

OBJECTIVES: To analyze MYO1B expression in gastric cancer, its association with long-term prognosis and its role in regulating biological behaviors of gastric cancer cells. METHODS: We analyzed MYO1B expression in gastric cancer and its correlation with tumor grade, tumor stage, and patient survival using the Cancer Public Database. We also examined MYO1B expression with immunohistochemistry in gastric cancer and paired adjacent tissues from 105 patients receiving radical surgery and analyzed its correlation with cancer progression and postoperative 5-year survival of the patients. GO and KEGG enrichment analyses were used to explore the biological functions of MYO1B and the key pathways. In cultured gastric cancer cells, we examined the changes in cell proliferation, migration and invasion following MYO1B overexpression and knockdown. RESULTS: Data from the Cancer Public Database showed that MYO1B expression was significantly higher in gastric cancer tissues than in normal tissues with strong correlations with tumor grade, stage and patient prognosis (P<0.05). In the clinical tissue samples, MYO1B was significantly overexpressed in gastric cancer tissues in positive correlation with Ki67 expression (r=0.689, P<0.05) and the parameters indicative of gastric cancer progression (CEA ≥5 μg/L, CA19-9 ≥37 kU/L, G3-4, T3-4, and N2-3) (P<0.05). Kaplan-Meier analysis and multivariate Cox regression analysis suggested that high MYO1B expression was associated with decreased postoperative 5-year survival and was an independent risk factor (HR: 3.522, 95%CI: 1.783-6.985, P<0.05). MYO1B expression level was a strong predictor of postoperative survival (cut-off value: 3.11, AUC: 0.753, P<0.05). GO and KEGG analyses suggested that MYO1B may regulate cell migration and the mTOR signaling pathway. In cultured gastric cancer cells, MYO1B overexpression significantly enhanced cell proliferation, migration, and invasion and promoted the phosphorylation of Akt and mTOR. CONCLUSIONS High MYO1B expression promotes proliferation, migration and invasion of gastric cancer cells and is correlated with poor patient prognosis.
Humans ; Stomach Neoplasms/metabolism* ; Cell Proliferation ; Prognosis ; Cell Movement ; Myosin Type I/genetics* ; Neoplasm Invasiveness ; Cell Line, Tumor ; Female ; Male

OBJECTIVES: To investigate the mechanism through which salidroside inhibits proliferation of gastric cancer (GC) cells focusing on glucose metabolic reprogramming pathways. METHODS: High-throughput sequencing combined with bioinformatics analysis was employed to identify the potential targets of salidroside in human GC MGC-803 cells. Liposome-mediated transfection experiments were carried out to validate the functional and mechanistic roles of these targets. CCK-8 and colony formation assays were used to assess the effects of salidroside on GC cell viability and clonogenic ability. qRT-PCR, Western blotting, and biochemical assay kits were used to analyze the regulatory effects of salidroside on the miR-1343-3p-OGDHL/PDHB enzyme complex-pyruvate metabolic pathway in GC cells. RESULTS: Bioinformatics analysis suggested that the tumor-suppressive factor miR-1343-3p negatively regulated the key glycolytic enzyme gene oxoglutarate dehydrogenase-like (OGDHL) in GC cells, and OGDHL and pyruvate dehydrogenase E1 subunit beta (PDHB) were both significantly upregulated in GC tissues, which was close by correlated with reduced survival rates of GC patients. In MGC-803 cells, salidroside treatment significantly enhanced the expression level of miR-1343-3p and downregulated OGDHL expression, resulting in disruption of the stability of PDHB, reduced pyruvate oxidative decarboxylation, and consequently decreased production of acetyl-CoA and ATP. CONCLUSIONS Salidroside inhibits GC cell proliferation possibly by regulating the miR-1343-3p-OGDHL/PDHB enzyme complex-pyruvate metabolic pathway, which provides new insights into its anti-tumor mechanisms and suggests new strategies for targeted therapy for GC.
Humans ; Stomach Neoplasms/pathology* ; MicroRNAs/genetics* ; Cell Proliferation/drug effects* ; Glucosides/pharmacology* ; Phenols/pharmacology* ; Cell Line, Tumor ; Glucose/metabolism* ; Pyruvate Dehydrogenase (Lipoamide)/metabolism*

Objective To investigate the effect of baicalein (BAI) on autophagy of gastric cancer cell line BGC-823 cells by upregulating microRNA-7-5p (miR-7) and its possible mechanism. Methods The MTT method was used to screen the optimal drug concentration of BGC-823 cells treated with BAI. Real-time quantitative PCR was used to detect the transfection efficiency of BGC-823 cell line stably transfected with miR-7. The experiment was divided into control group (mimic-NC), miR-7 group (miR-7 mimic) and BAI group ( miR-7 overexpression combined with BAI treatment group). MTT assay, plate cloning assay and EdU assay were used to detect cell proliferation. The expression levels of autophagy related 16 like 1 (ATG16L1), sequestosome 1 (p62), Beclin 1, autophagy-related protein 5 (ATG5) and microtubule-assaiated protein 1 light chain3 (LC3) were detected by immunofluorescence staining and Western blot. Network pharmacology analysis to predict possible signaling pathways; Western blot was used to detect the expression levels of phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway. Results 50 μmol/L BAI significantly inhibited the proliferation ability of BGC-823 cells; Compared with the control group, the expression level of miR-7 was significantly increased after BAI treatment. The cell proliferation of the miR-7 group was significantly inhibited, and the protein expression level of autophagy-related proteins and the LC3II/LC3I ratio were significantly up-regulated, which promoted the formation of autophagosomes and inhibited the formation of autophagic flow in BGC-823 cells. Compared with the miR-7 group, the BAI group could further inhibit the proliferation of BGC-823 cells, induce the formation of autophagosomes, but inhibit the production of autophagy flow. Network pharmacology analysis showed that the common target genes of BAI, gastric cancer and autophagy may be related to PI3K/AKT signaling pathway. Compared with the control group, the phosphorylation levels of p-PI3K, p-AKT and p-mTOR in the miR-7 group were significantly inhibited, and the phosphorylation levels of these proteins were further inhibited in the BAI group. Conclusion BAI-mediated miR-7 inhibits the formation of autophagosomes in BGC-823 cells by inhibiting PI3K/AKT/mTOR signaling pathway, and inhibits the generation of autophagic flow.
Humans ; MicroRNAs/metabolism* ; Stomach Neoplasms/drug therapy* ; Autophagy/genetics* ; Cell Line, Tumor ; Flavanones/pharmacology* ; Cell Proliferation/genetics* ; TOR Serine-Threonine Kinases/genetics* ; Signal Transduction/drug effects* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/genetics* ; Gene Expression Regulation, Neoplastic/drug effects*

OBJECTIVES: To investigate the expression of cartilage acidic protein 1 (CRTAC1) in gastric cancer (GC) and its effect on biological behaviors and immune cell infiltration of GC. METHODS: Transcriptomic, GO and KEGG analyses were conducted to investigate the association of CRTAC1 expression with prognosis of GC patients and its involvement in cell function and signaling pathways. ESTIMATE algorithm was used to analyze the effect of CRTAC1 expression on the tumor microenvironment and the tumor mutation load. In two GC cell clines (HGC-27 and MKN-74), CCK8, EdU and clone formation assays, flow cytometry, and Hoechst staining were used to examine the effects of CRTAC1 knockdown on cell proliferation, cell cycle changes and apoptosis. Wound healing assay, Transwell assay, and Western blotting were performed to analyze the effect of CRTAC1 knockdown on GC cell migration and the underlying mechanism. RESULTS: Bioinformatics analysis showed significantly higher expression of CRTAC1 in GC tissues than in adjacent tissues (P<0.05). Age and tumor stage were both prognostic risk factors in GC patients with high CRTAC1 expression (P<0.001). Analysis using ESTIMATE algorithm showed that CRTAC1 expression increased immune cell infiltration and decreased tumor mutational load in GC (P<0.001). In HGC-27 and MKN-74 cells, CRTAC1 knockdown significantly inhibited cell proliferation and migration and promoted cell apoptosis. Western blotting demonstrated that CRTAC1 knockdown significantly increased E-cadherin expression and reduced the expression levels of vimentin, p-PI3K, AKT2, p-AKT and p-mTOR in GC cells. CONCLUSIONS High expression of CRTAC1 in GC tissues affects immunotherapeutic efficacy and prognosis of the patients, possibly by promoting epithelial-mesenchymal transition via modulating tumor mutational load, tumor microenvironment, and the PI3K/AKT signaling pathway.
Stomach Neoplasms/metabolism* ; Humans ; Cell Proliferation ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Signal Transduction ; Cell Movement ; Cell Line, Tumor ; Prognosis ; Apoptosis ; Tumor Microenvironment ; Female ; Male ; Epithelial-Mesenchymal Transition/genetics*

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS 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.
Animals ; Mice ; RNA, Long Noncoding/metabolism* ; Stomach Neoplasms/pathology* ; Mice, Nude ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Carcinogenesis/genetics* ; Cell Movement/genetics* ; Epithelial-Mesenchymal Transition/genetics* ; Gene Expression Regulation, Neoplastic ; Apoptosis/genetics*

Objective To investigate the impacts of forkhead box M1(FOXM1)on the proliferation,invasion,and drug resistance of gastric cancer cells by regulating the circular RNA circ_NOTCH1.Methods Western blotting and real-time quantitative PCR were performed to determine the expression of FOXM1 protein and circ_NOTCH1,respectively,in the gastric cancer tissue,para-carcinoma tissue,human normal gastric mucosa epithelial cell line GES-1 and gastric cancer cell lines MGC-803,HGC-27,and BGC-823.BGC-823 cells were classified into the following groups:control,short hairpin RNA FOXM1(sh-FOXM1)and negative control(sh-NC),small interfering RNA circ_NOTCH1(si-circ_NOTCH1)and negative control(si-NC),and sh-FOXM1+circ_NOTCH1 overexpression plasmid(sh-FOXM1+pcDNA-circ_NOTCH1)and sh-FOXM1+negative control(sh-FOXM1+pcDNA).CCK-8 assay and clone formation assay were employed to measure the cell proliferation,and Transwell assay to measure cell invasion.After treatment with 1.0 mg/L adriamycin for 48 h,the cell resistance in each group was analyzed.Western blotting was employed to determine the expression levels of FOXM1,proliferating cell nuclear antigen(PCNA),Bax,multi-drug resistance-associated protein 1(MRP1),and multi-drug resistance gene 1(MDR1).RNA pull-down and RNA immunoprecipitation were employed to examine the binding of circ_NOTCH1 to FOXM1 protein.Results Compared with those in the para-carcinoma tissue,the expression levels of FOXM1 protein and circ_NOTCH1 in the gastric cancer tissue were up-regulated(all P<0.001).Compared with GES-1 cells,MGC-803,HGC-27,and BGC-823 cells showed up-regulated expression levels of FOXM1 protein and circ_NOTCH1(all P<0.001).Compared with the control group and sh-NC group,the sh-FOXM1 group with down-regulated expression of FOXM1 protein and circ_NOTCH1 showed decreased optical density value,clone formation rate,cell invasion number,and cell viability,down-regulated expression of PCNA,MRP1,and MDR1,and up-regulated expression of Bax protein in BGC-823 cells(all P<0.001).Compared with the control group and the si-NC group,the si-circ_NOTCH1 group with down-regulated expression of circ_NOTCH1 showed decreased optical density value,clone formation rate,cell invasion number,and cell viability,down-regulated expression of PCNA,MRP1,and MDR1,and up-regulated expression of Bax protein in BGC-823 cells(all P<0.001).Compared with sh-FOXM1 group and sh-FOXM1+pcDNA group,the sh-FOXM1+pcDNA-circ_NOTCH1 group with up-regulated expression of circ_NOTCH1 showed increased optical density value,clone formation rate,cell invasion number,and cell viability,up-regulated expression of PCNA,MRP1,and MDR1,and down-regulated expression of Bax protein(all P<0.001).FOXM1 protein was able to interact with circ_NOTCH1.Conclusion Interference with FOXM1 may inhibit the proliferation,invasion,and drug resistance of gastric cancer cells by silencing circ_NOTCH1 expression.
Humans ; bcl-2-Associated X Protein/metabolism* ; Carcinoma ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Drug Resistance ; Forkhead Box Protein M1/metabolism* ; Gene Expression Regulation, Neoplastic ; MicroRNAs/genetics* ; Proliferating Cell Nuclear Antigen/metabolism* ; Receptor, Notch1/metabolism* ; RNA, Small Interfering/genetics* ; Stomach Neoplasms/genetics*