SGC-7901 Cells Research Articles

Retraction Note to: Lupeol enhances inhibitory effect of 5-fluorouracil on human gastric carcinoma cells.

Lupeol, a dietary triterpene present in many fruits and medicinal plants, has been reported to possess many pharmacological properties including cancer-preventive and anti-cancer effects in vitro and in vivo. Here, we investigated the anti-cancer efficacy and adjuvant chemotherapy action of lupeol in gastric cancer (GC) cells (SGC7901 and BGC823) and explored the underlying mechanisms. Cells were treated with lupeol and/or 5-fluorouracil (5-Fu) and subjected to cell viability, colony formation, apoptosis, western blot, semiquantitative RT-PCR, and xenograft tumorigenicity assay. Our results showed that lupeol and 5-Fu inhibited the proliferation of SGC7901 and BGC823 cells, and combination treatment with lupeol and 5-Fu resulted in a combination index < 1, indicating a synergistic effect. Co-treatment with lupeol and 5-Fu induced apoptosis through up-regulating the expressions of Bax and p53 and down-regulating the expressions of survivin and Bcl-2. Furthermore, co-treatment displayed more efficient inhibition of tumor weight and volume on BGC823 xenograft mouse model than single-agent treatment with 5-Fu or lupeol. Taken together, our findings highlight that lupeol sensitizes GC to 5-Fu treatment, and combination treatment with lupeol and 5-Fu would be a promising therapeutic strategy for human GC treatment.

Precise Targeting Therapy of Orthotopic Gastric Carcinoma by siRNA and Chemotherapeutic Drug Codelivered in pH-Sensitive Nano Platform.

Gastric cancer is one of the most common malignant tumors, which remains as an obstacle to human health. Nowadays, targeted nanoparticles to gastric tumor tissues, provide new strategy for improved therapy but still remain challenging. The major hurdle of targeted therapeutic nanoparticles comes from the limited enrichment and poor selectivity of therapeutic agents in in situ tumor. Herein, a pH-sensitive targeted nano platform coloaded As2 O3 and human epidermal growth factor receptor-2 (HER2)-siRNA (AH RNPs) is developed to achieve targeting therapy in orthotopic gastric carcinoma. AH RNPs can effectively prevent the degradation of siRNA and overcome the poor solubility of As2 O3 . In vitro studies show that AH RNPs could achieve synergistic inhibition of growth and metastasis on SGC7901 cells. Surprisingly, AH RNPs not only target gastric subcutaneous tumor, but also target in situ tumor, and express loaded genes in in situ tumor. Moreover, AH RNPs show excellent antitumor effect in orthotopic gastric tumor model and the anticancer mechanism is related about inhibiting the activation of ERK signal and downregulating the expression of cxc chemokine receptor 4 (CXCR4), HER2, MMP2, and MMP9 protein. This study provides a multi-functional vector for precise targeting therapy of gastric cancer, which may serve as a potential clinical application for future gastric cancer.

Gastrokine 2 Regulates the Antitumor Effect of JAK2/STAT3 Pathway in Gastric Cancer.

GKN2 (gastrokine 2) mainly plays a regulatory role in gastric mucosal defense and cell protection mechanisms, and its role in gastric cancer has not been thoroughly elucidated. Immunohistochemistry was used to detect GKN2 and TFF1 expressions in 90 gastric cancer tissues, 48 neoplastic resection margins, and 22 normal gastric mucosa epithelia. It showed that the downregulation of GKN2 and TFF1 expressions in gastric cancer tissues was significantly different from that in adjacent normal gastric tissues and distal gastric mucosal tissues. Nevertheless, correlation analysis showed that GKN2 expression in gastric cancer tissues was independent of TFF1 expression. After overexpression of GKN2 was constructed in human gastric cancer cell line MKN28 with the Ad-GFP-GKN2 transfected, cell viability was measured by CCK-8 assay, and migration and invasion ability were analyzed by transwell migration assay and transwell invasion assay. It indicated that overexpression of GKN2 significantly reduced the viability of MKN28 and SGC7901 cells. Overexpression of GKN2 could also inhibit the migration and invasion ability in MKN28 and SGC7901 cells. In addition, upregulation of GKN2 can inactivate the JAK2/STAT3 pathway. Our data suggest that GKN2 and TFF1 play the antitumor role in gastric carcinoma, and TFF1 may not interact or cooperate with GKN2. GKN2 overexpression can inhibit the growth and metastasis by downregulating the JAK2/STAT3 pathway in gastric cancer cells.

Daam1 Overexpression Promotes Gastric Cancer Progression and Regulates ERK and AKT Signaling Pathways

ObjectiveThe dishevelled-associated activator of morphogenesis 1 (DAAM1) has been reported to be closely associated with human cancers. However, its involvement in human gastric cancer (GC) remains largely unexplored. This study aimed to investigate the clinical significance and biological roles of Daam1 in human GC.MethodsDaam1 protein expression was examined in 124 cases of gastric adenocarcinomas using immunohistochemistry. Daam1 plasmid and siRNA transfection were carried out in SGC7901 and AGS cell lines. CCK-8, colony formation, Annexin V/PI, JC-1 staining, and Western blotting were used to explore the biological functions and potential underlying mechanisms of Daam1 in GC cells.ResultsOur results showed that Daam1 was overexpressed in GC specimens. A high Daam1 level was associated with tumor-node-metastasis (TNM) stage, T status, nodal metastasis, and poor patient survival. Analysis of the Oncomine dataset revealed upregulation of Daam1 mRNA in GC tissues. Western blot showed that Daam1 protein expression was higher in GC cell lines compared to the normal GES-1 cell line. CCK-8 and colony formation assays showed that ectopic Daam1 expression upregulated the cell growth rate and colony number in SGC-7901 cells, while Daam1 siRNA knockdown downregulated the growth rate and colony number in AGS cells. CCK-8 and Annexin V/PI apoptosis assays demonstrated that Daam1 overexpression decreased cisplatin sensitivity and downregulated cisplatin-induced apoptosis. JC1 staining showed that Daam1 overexpression upregulated, while Daam1 depletion downregulated mitochondrial membrane potential. Mechanistically, Daam1 overexpression downregulated p21 and upregulated p-ERK and p-AKT. The increased proliferation rate and decreased cisplatin sensitivity/apoptosis induced by ectopic Daam1 were reversed after treatment with AKT and ERK inhibitors.ConclusionTaken together, our results showed that Daam1 overexpression was associated with poor prognosis and promoted malignant activity via regulation of ERK and AKT pathways in GC cells, indicating Daam1 is a malignant biomarker and potential therapeutic target in GC.

Effect and mechanism of downregulating the long-chain noncoding RNA TM4SF1-AS1 on the proliferation, apoptosis and invasion of gastric cancer cells

BackgroundTo investigate long-chain noncoding TM4SF1-AS1 in gastric cancer (GC) tissues and cells.MethodsTM4SF1-AS1 in 40 GC tissues and adjacent tissues was detected and compared using real-time fluorescence quantitative PCR (qRT-PCR). TM4SF1-AS1 in MKN28 and SGC7901 GC cells was downregulated using small interfering RNA (shRNA). The cells were grouped into an interference group (shTM4SF1-AS1 group) and a control group (shControl group). MTT and Transwell tests were applied to determine the proliferation and invasion of the cells in both groups, and flow cytometry was performed to assess the apoptosis rate in the two groups. Western blotting was performed to determine changes in key proteins in cells during the epithelial-to-mesenchymal transition (EMT) and in the TM4SF1 and PI3K-AKT signalling pathways in response to the downregulation of TM4SF1-AS1.ResultsThe proliferation of MKN28 and SGC7901 in the shTM4SF1-AS1 group was significantly inhibited at 48 h and 72 h compared to that in the shControl group (all P < 0.05). In the shTM4SF1-AS1 group, the number of invaded MKN28 and SGC7901 cells was significantly lower than that in the shControl group (all P < 0.05). Apoptosis in the MKN28 and SGC7901 shTM4SF1-AS1 groups was significantly higher than that in the shControl group (all P < 0.05). Compared to those in the shControl group, levels of E-cadherin in EMT-related proteins were significantly elevated (P < 0.01), while levels of N-cadherin, Snail and Twist1 were significantly decreased (all P < 0.01). After silencing the expression of LncTM4SF1-AS1, the expression levels of TM4SF1 in the shTM4SF1-AS1 group were downregulated compared to those in the shControl group, and the p-PI3K and p-AKT proteins in the PI3K-AKT signalling pathway in the shTM4SF1-AS1 group were downregulated compared to those of the shControl group.ConclusionsTM4SF1-AS1 is upregulated in gastric cancer tissues and cells. Interfering with and downregulating its expression inhibit cancer cell proliferation, invasion and the EMT and promote apoptosis. The underlying mechanism for these effects is related to silencing the TM4SF1 and PI3K-AKT signalling pathways. TM4SF1-AS1 may be a potential therapeutic target for gastric cancer.

ITGB1 Enhances the Proliferation, Survival, and Motility in Gastric Cancer Cells

ITGB1 (Integrin β1, CD29) is a member of the integrin family and has a role as a major adhesion receptor. Gastric cancer (GC) is an important cause of mortality worldwide, especially in China. As a potential cancer enhancer, the role ITGB1 plays in GC progression remains unclear. In the current study, our assay on the databases of tumoassociated gene expression and interaction found that the high expression of ITGB1 was closely correlated with the poor prognosis of GC patients. To explore the roles, ITGB1 plays in GC progression, and an ITGB1-deleted cell line (ITGB1−/−SGC7901) was generated using the CRISPR/Cas9 method. The tumor malignancy-associated cell behaviors and microstructures were detected, imaged, and analyzed using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), wound healing, transwell, scanning electron microscopy, laser scanning confocal microscopy, and others. The results indicated that ITGB1 deletion decreased the GC cell proliferation and motility, and inhibited motility-relevant microstructures, such as pseudopodia and filopodia, markedly in ITGB1-deleted SGC7901 cells. The analysis of STRING database and western blots indicated that ITGB1 contributes to the malignancy of GC mediated by Src-mediated FAK/PI3K/Akt signaling pathways. Taken together, the results showed that ITGB1 may be a potential targeting marker for GC diagnosis and therapy in the future.

MiR-1299 functions as a tumor suppressor to inhibit the proliferation and metastasis of gastric cancer by targeting ARF6.

MiRNAs belong to non-coding RNAs that are involved in cancer development. Acting as a mediator, they could regulate the expression level of numerous gens. However, the expression and function of miR-1299 in gastric cancer (GC) are not clear. To explore the role of miR-1299 in the process of GC. We detected the levels of miR-1299 in clinical samples of GC and investigated the role of miR-1299 in the regulation of the GC cells proliferation, apoptosis and metastasis. Luciferase reporter assay was employed to verify the target of miR-1299. Additionally, the proliferation, apoptosis and metastasis of AGS and SGC7901 cells were analyzed after the overexpression of miR-1299. Our study showed the expression of miR-1299 was decreased in GC tissues and cell lines. It indicated that the cell proliferation, migration and invasion was inhibited, while the cell apoptosis was promoted by the over-expressed miR-1299. Also, we found that miR-1299 could directly target the 3'-untranslated region (3'UTR) of ARF6 genes. In addition, rescue assay demonstrated that miR-1299 overexpression promoted the cell apoptosis and inhibited cell growth, which could be attenuated by the overexpression of ARF6. These findings indicate that miR-1299 regulates cell progression in GC by targeting ARF6 genes, and suggest that miR-1299 may be a tumor suppressor in the GC progression.

Systematic Understanding of the Mechanism of Baicalin against Gastric Cancer Using Transcriptome Analysis.

Background Gastric cancer (GC) is the most common type of cancer. It is highly malignant and is characterized by rapid and uncontrolled growth. The antitumour activity of Baicalin was studied in multiple cancers. However, its mechanism of action has not been fully elucidated. We provided a systematic understanding of the mechanism of action of baicalin against GC using a transcriptome analysis of RNA-seq. Methods Human GC cells (SGC-7901) were exposed to 200 μg/ml baicalin for 24 h. RNA-seq with a transcriptome, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to identify the antitumour effects of baicalin on SGC-7901 cells in vitro. A protein-protein interaction (PPI) network of differentially expressed genes (DEGs) was constructed. A competitive endogenous RNA (ceRNA) network was constructed and further analysed after validation using qRT-PCR. Results A total of 68 lncRNAs, 20 miRNAs, and 1648 mRNAs were differentially expressed in baicalin-treated SGC-7901 GC cells. Three lncRNAs, 6 miRNAs, and 7 mRNAs were included in the ceRNA regulatory network. GO analysis revealed that the main DEGs were involved in the biological processes of the cell cycle and cell death. KEGG pathway analysis further suggested that the p53 signalling pathway was involved in the baicalin-induced antitumour effect on SGC-7901 cells. Further confirmation using qPCR indicated that baicalin induced an antitumour effect on SGC-7901 cells, which is consistent with the results of the sequencing data. Conclusions In summary, the mechanism of baicalin against GC involves multiple targets and signalling pathways. These results provide new insight into the antitumour mechanism of baicalin and help the development of new strategies to cure GC.

High-Throughput Characterization of Cell Adhesion Strength Using Long-Channel Constriction-Based Microfluidics.

The adhesion strength of a cancer cell is a valuable biophysical marker of its metastatic potential, tightly associated with various metastatic processes; for example, cancer cells escape from a primary tumor, and circulating tumor cells (CTCs) are anchored to the vessel wall. Although constriction-based microfluidics can realize the high-throughput characterization of single-cell deformability, due to the influence of cell size heterogeneity, accurately evaluating the adhesion strength of a cancer cell at high throughputs in constriction remains difficult. In this paper, we first proposed an approach for the assessment of adhesion strength of BGC-823 and SGC-7901 cell lines at high throughputs based on a friction coefficient using the constant velocity stage of cell transit in a long-channel constriction. Cell size was proven to be independent of adhesion strength by cell detachment assay; however, it has large effects on cell transit velocity in constriction. Therefore, the linear elasticity of a completely deformed cell in constriction is simplified as a compressed spring model, effectively reducing the influence of cell size heterogeneity. Theoretically, our proposed model can well offset the influence of cell size by cell transit velocity, while our experimental results indicate that the friction coefficient has a good linear relationship with the logarithm of the adhesion strength too. Therefore, our proposed approach can realize accurate characterization of cell adhesion strength at high throughputs using long-channel constriction-based microfluidics. Hence, this work might enrich the functions of constriction-based microfluidics and bring new insights into the characterization of mechanical phenotypes.

Taurochenodeoxycholic acid inhibits the proliferation and invasion of gastric cancer and induces its apoptosis.

Taurochenodeoxycholic acid (TCDCA) is the principal ingredient of Compound Shougong Powder. Despite traditional Chinese medicine (TCM) research demonstrates that Compound Shougong Powder can restrict tumor growth, whether TCDCA exerts a role in suppressing cancer as the major ingredient of Compound Shougong Powder remains unknown. This study aims to clarify the regulatory mechanism of TCDCA on gastric cancer. Gastric cancer cells SGC-7901 were cultured to investigate the effects of TCDCA on proliferation and apoptosis. Furthermore, a subcutaneously implanted tumor model was established using SGC-7901 cells in BALB/C nude mice and tumor volume was measured under low and high dose treatment of TCDCA. Cell proliferation, apoptosis, and invasion were subjected to 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, flow cytometry, and transwell assay. Differentially expressed genes were screened by transcriptome sequencing. Nude mouse tumorigenicity assay was initiated to identify the effect of TCDCA on both tumor volume and weight, and the expression of candidate genes screened by transcriptome sequencing was determined by real-time fluorescence quantification (qPCR) and Western blot. The experiments revealed that TCDCA could significantly inhibit the proliferation and invasion of gastric cancer cells and induce apoptosis of these cells. Meanwhile, test findings via in vivo indicated that TCDCA severely diminished the volume and weight of tumors. This study first demonstrated that TCDCA inhibited the proliferation and invasion of gastric cancer and induced apoptosis, which is expected to serve as an experimental basis for the application of TCM in tumor therapeutic options. PRACTICAL APPLICATIONS: Through this study, the inhibitory effect of Taurochenodeoxycholic acid on gastric cancer can be clarified, which provides a new research basis for the application of traditional Chinese medicine (TCM) and TCM monomer in cancer. In addition, this study can further promote the research and application of Chinese traditional medicine, which has important application value and economic benefits.

Effects and Mechanisms of Saikosaponin D Improving the Sensitivity of Human Gastric Cancer Cells to Cisplatin.

Gastric cancer (GC) is the second leading cause of cancer deaths around the world. Chemoresistance is an important reason for poor prognosis of GC. Saikosaponin D (SSD) is a natural constituent from Radix Bupleuri and exhibits various activities including antitumors. This study investigated the effects and the mechanisms of SSD on cisplatin (cis-diamminedichloroplatinum, DDP) sensitivity of GC cells. Findings suggested that SSD could promote the inhibitory effect of DDP on proliferation and invasion and increase DDP-induced apoptosis in SGC-7901 and DDP-resistant cell line SGC-7901/DDP. We further identified that SSD increased levels of LC3 B and cleaved caspase 3 and decreased levels of p62, IKK β, p-IκB α, and NF-κB p65, suggesting that SSD might inhibit the IKK β/NF-κB pathway and induce both cell autophagy and apoptosis in SGC-7901 and SGC-7901/DDP. A further study indicated that SSD enhanced the effect of DDP-induced cleaved caspase 3 level rise and NF-κB pathway suppression, especially in SGC-7901/DDP cells. Conclusively, SSD enhanced DDP sensitivity of GC cells; the potential molecular mechanisms were that SSD-induced apoptosis and autophagy and inhibited the IKK β/NF-κB pathway in GC cells. These findings suggested that SSD might contribute to overcoming DDP resistance in GC treatment.

Zinc oxide nanoparticles reduce the chemoresistance of gastric cancer by inhibiting autophagy.

BACKGROUNDGastric cancer (GC) is a common malignancy that results in a high rate of cancer-related mortality. Cisplatin (DDP)-based chemotherapy is the first-line clinical treatment for GC therapy, but chemotherapy resistance remains a severe clinical challenge. Zinc oxide nanoparticle (ZnO-NP) has been identified as a promising anti-cancer agent, but the function of ZnO-NP in GC development is still unclear.AIMTo explore the effect of ZnO-NP on chemotherapy resistance during GC progression.METHODSZnO-NP was synthesized, and the effect and underlying mechanisms of ZnO-NP on the malignant progression and chemotherapy resistance of GC cells were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, colony formation assays, transwell assays, wound healing assays, flow cytometry, and Western blot analysis in GC cells and DDP-resistant GC cells, and by tumorigenicity analyses in nude mice.RESULTSOur data revealed that ZnO-NP was able to inhibit proliferation, migration, and invasion and induce apoptosis of GC cells. Meanwhile, ZnO-NP significantly reduced the half maximal inhibitory concentration (IC50) of DDP for the inhibition of cell proliferation of DDP-resistant SGC7901/DDP cell lines. Autophagy was increased in DDP-resistant GC cells, as demonstrated by elevated light chain 3-like protein 2 (LC3II)/LC3I and Beclin-1 expression and repressed p62 expression in SGC7901/DDP cells compared to SGC7901 cells. Mechanically, ZnO-NP inhibited autophagy in GC cells and treatment with DDP induced autophagy, which was reversed by ZnO-NP. Functionally, ZnO-NP attenuated the tumor growth of DDP-resistant GC cells in vivo.CONCLUSIONWe conclude that ZnO-NP alleviates the chemoresistance of GC cells by inhibiting autophagy. Our findings present novel insights into the mechanism by which ZnO-NP regulates the chemotherapy resistance of GC. ZnO-NP may serve as a potential therapeutic candidate for GC treatment. The potential role of ZnO-NP in the clinical treatment of GC needs clarification in future investigations.

Effects of betulinic acid on apoptosis of human gastric cancer MGC-803 cells

Objective: The effects of betulinic acid (BA) on apoptosis of human gastric cancer MGC-803 cells was investigated by using human gastric cancer MGC-803 cells as experimental materials, and the basis for its clinical application was provided. Methods: The human gastric cancer MGC-803 cells were divided into 4 groups,each group was set with 3 replicates.The control group was MGC-803 cells without being added betulinic acid; the other 3 groups of experimental groups were treated with betulinic acid at final concentrations of 10, 20 and 30 μg /ml respectively. Cells were treated with betulinic acid of different concentrations for 48 h. Laser confocal microscope was used to observe morphological changes of MGC-803. The activities of Caspase-3 and Caspase-9 were detected by an assay kit. Flow cytometry was applied to determine mitochondrial membrane potential. The mRNA and protein levels of Caspase-3, Caspase-9 and Cyt c were also detected by qRT-PCR and Western blot, respectively. Results: Compared with the control group, the activities of Caspase-3 and caspase-9 were increased(P＜0.01), while the mitochondrial membrane potential was decreased significantly(P＜0.01). The mRNA and protein expressions of Caspase-3, caspase-9 and Cyt c were up-regulated significantly(P＜0.01). Conclusion: In the final concentration range of 10 ~ 30 μg/ml, betulinic acid can induce apoptosis of human gastric cancer MGC-803 cells by regulating the expression of Caspase-3, Caspase-9 and Cyt c.

Hsa-miR-30a-3p attenuates gastric adenocarcinoma proliferation and metastasis via APBB2.

Background: There is a well-established relationship between cell cycle progression and the development of stomach adenocarcinoma. This study aimed to elucidate the molecular mechanism and biological function of APBB2 in gastric cancer.Methods: Gastric adenocarcinoma (GA) data were downloaded from the TCGA-GA and GEO databases and analyzed to explore differentially expressed miRNAs and mRNAs. Moreover, potential target mRNAs were also predicted. The relative level of gene and protein expression in GA cell lines and gastric mucosa cells was detected by q-PCR and Western blot, respectively. Moreover, the influence of APBB2 on proliferation, metastasis, and cell cycle changes in SGC-7901 and BGC-823 cells was evaluated. The binding relationship between the target miRNA and mRNA was confirmed with a dual-luciferase reporter assay.Results: High APBB2 expression was detected in GA patients, indicating that it may be represent a predictive biomarker for poor prognosis. Related experiments confirmed that APBB2 silencing inhibited GA cellular functions, including proliferation, cell cycle progression, migration, and invasion. In addition, to explore the molecular mechanism, our results indicated that the binding sites were located at hsa-mir-30a and the 3′-UTR of APBB2, suggesting that hsa-mir-30a can regulate the expression of APBB2. The biological functions of hsa-mir-30a were also evaluated. Hsa-mir-30a overexpression attenuated the proliferation and metastasis of cancer cells. In rescue experiments, hsa-mir-30a was confirmed to reverse the cell cycle promoting function associated with APBB2 overexpression.Conclusion: Our findings show that hsa-mir-30a can attenuate the development of GA by down-regulating APBB2 expression.

Protective role of astragaloside IV in gastric cancer through regulation of microRNA-195-5p-mediated PD-L1

Aim Astragaloside IV (AS-IV) was reported to exert anti-cancer function in many cancers, but its actions in gastric cancer (GC) remain unclear. In the present study, we tried to elaborate the underlying mechanism by which AS-IV regulated the epithelial-mesenchymal transition (EMT) and angiogenesis of GC cells. Methods The expressions of hsa-miR-15b-5p, hsa-miR-15a-5p, hsa-miR-195-5p, hsa-miR-424-5p and hsa-miR-497-5p in GC tissues and adjacent normal tissues were predicted by TCGA database. SGC7901 or MGC803 cells were treated with AS-IV, or transfected with miR-195-5p inhibitor/mimic or pcDNA3.1-PD-L1 followed by detection of cell proliferation, EMT and angiogenesis. The target relation between miR-195-5p and PD-L1 was confirmed by dual luciferase reporter gene assay. Results Elevated hsa-miR-15b-5p, hsa-miR-15a-5p and hsa-miR-424-5p expressions were found in GC tissues, while decreased hsa-miR-195-5p and hsa-miR-497-5p expressions were observed in GC tissues. AS-IV inhibits EMT and angiogenesis in GC. PD-L1 was a potential target of miR-195-5p. Down-regulation of miR-195-5p or elevated PD-L1 expression reverses the inhibitory effect of AS-IV on EMT and angiogenesis of GC cells. Conclusion The present study demonstrated that AS-IV inhibited EMT and angiogenesis in GC through upregulation of miR-195-5p, highlighting the potential therapeutic effect of AS-IV on GC via miR-195-5p-regulated PD-L1.

Total saponins from Tupistra chinensis baker inhibits growth of human gastric cancer cells in vitro and in vivo

Ethnopharmacological relevanceTupistra chinensis Baker (syn. Rohdea chinensis), an antitumor folk herb mainly distributed in China, its rhizome has been historically used to treat gastric cancer. Studies showed that the steroidal saponins were the main bioactive components in the rhizome of T. chinensis. Our previous studies have confirmed that the steroidal saponins have a variety of anti-tumor activities. However, the underlying anti-tumor mechanism of the total steroidal saponins of T. chinensis (TCS) remains to be revealed. Aim of the studyIn the present study, we studied the potential anti-proliferative activity and anti-tumor mechanism of TCS on gastric cancer in vitro and in vivo. MethodsIn vitro, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to detect the proliferation ability of TCS on SGC-7901 cells and AGS cells. Flow cytometry were performed to analyze cell apoptosis, cell cycle, mitochondrial membrane potential and reactive oxygen species expression level. Western blotting was performed to validate the expression of proteins in related pathways. In vivo, a xenograft model was established by injecting SGC-7901 cells into nude mice. ResultsIn vitro, TCS inhibited the proliferation of gastric cancer cells. TCS effectively induced apoptosis by PI3K/Akt/mTOR signaling pathway in SGC-7901 cells, and promoted apoptosis via p53-mediated pathway in AGS cells. TCS also exhibited inhibitory activity in blocking the migration of gastric cancer cells. In vivo, TCS significantly inhibited the growth of xenograft tumor. ConclusionThese results indicated that TCS exhibited significant anti-gastric cancer effects in vitro and in vivo.

MiR-504 Promoted Gastric Cancer Cell Proliferation and Inhibited Cell Apoptosis by Targeting RBM4.

Background The purpose of this study was to explore the role and underlying mechanism of miR-504 and RBM4 in gastric cancer. Methods The qRT-PCR or Western blot was performed to determine the expressions of miR-504 and RBM4 in the gastric cancer tissues and normal tissues. Human SGC-7901 cells were transfected with miR-504 mimic/inhibitor or pcDNA-RBM4. Cell proliferation and cell apoptosis were assessed by colony formation assay and flow cytometry, respectively. Luciferase reporter gene assays were used to investigate interactions between miR-504 and RBM4 in SGC-7901 cells. Results The relative expression of miR-504 was significantly upregulated in the gastric cancer group (n = 25) than in the paired normal group (n = 25), but the relative RBM4 expression was remarkably downregulated in the gastric tumor group, compared with the normal group. Additionally, miR-504 overexpression increased the viability of gastric cancer cells. Moreover, RBM4 is a functional target of miR-504 in gastric cancer cells. miR-504 was further confirmed to promote SGC-7901 cell proliferation and inhibit cell apoptosis by downregulation RBM4 in vitro. Conclusions miR-504 promotes gastric cancer cell proliferation and inhibits cell apoptosis by targeting RBM4, and this provides a potential diagnostic biomarker and treatment for patients with gastric cancer.

Mortalin/glucose-regulated protein 75 promotes the cisplatin-resistance of gastric cancer via regulating anti-oxidation/apoptosis and metabolic reprogramming

Platinum drug treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). However, the therapeutic effect is less than satisfactory, largely due to the acquired resistance to platinum drugs. Therefore, a better understanding of the underlying mechanisms can greatly improve the therapeutic efficacy of GC. In this study, we aimed to investigate the chemo-resistance related functions/mechanisms and clinical significance of glucose-regulated protein 75 (GRP75) in GC. Here, our data showed that compared with SGC7901 cells, the expression of GRP75 was markedly higher in cisplatin-resistance cells (SGC7901CR). Knockdown of GRP75 abolished the maintenance of mitochondrial membrane potential (MMP) and inhibited the nuclear factor erythroid-2-related factor 2 (NRF2), phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT), hypoxia-inducible factor 1α (HIF-1α), and c-myc, which resulted in blocking the activation of their downstream targets. These processes attenuated the anti-oxidation/apoptosis abilities and altered the metabolic reprogramming in SGC7901CR cells, leading to re-sensitizing these cells to cisplatin. However, overexpression of GRP75 in SGC7901 cells caused the opposite effects. A xenografts model confirmed the abovementioned results. In GC patients receiving platinum chemotherapy and a meta-analysis, a high level of GRP75 was positively associated with aggressive characteristics and poor prognosis including but not limited to gastrointestinal cancers, and was an independent predictor for overall survival. Collectively, our study indicated that GRP75 was involved in the cisplatin-resistance of GC and that GRP75 could be a potential therapeutic target for restoring the drug response in platinum-resistance cells and a useful additive prognostic tool in guiding clinical management of GC patients.

LncRNA AFAP1-AS1 Modulates the Proliferation and Invasion of Gastric Cancer Cells by Regulating AFAP1 via miR-205-5p.

PurposeThe present study investigated the expression and function of the long noncoding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) related to gastric cancer (GC), based on previous results from a microarray analysis.MethodsReal-time quantitative polymerase chain reaction (qPCR) was used to verify the expression of AFAP1-AS1 in 97 fresh GC tissues and paired non-GC tissues, as well as in six different GC cell lines (BGC-823, SGC-7901, MGC-803, AGS, MKN-45, and MKN-28). The expression levels were subsequently correlated with the clinicopathological features of patients. siRNA against AFAP1-AS1 was transfected into GC cell lines, and cell proliferation, migration, and invasion were detected before and after silencing of AFAP1-AS1 expression. Luciferase reporter gene analysis was used to confirm the target gene of microRNA-205-5p (miR-205-5p) in 293T cells. The potential mechanism was subsequently investigated.ResultsqPCR results showed that AFAP1-AS1 was significantly overexpressed in GC tumor tissues and also GC cell lines, comparing to their paired non-GC tissues. Furthermore, statistical analysis revealed that the overexpression of AFAP1-AS1 was significantly correlated with tumor size (p=0.018) and grade of differentiation (p=0.042). Subsequently, artificially decreasing the expression of AFAP1-AS1 with its specific siRNA dramatically inhibited the proliferation, migration and invasion of GC cell lines (SGC-7901 and BGC-823 cells). Mechanical analysis suggested that AFAP1-AS1 is involved in regulation of its maternal gene, AFAP1, at both mRNA level and protein level. Luciferase reporter gene assay indicated that lncRNA AFAP1-AS1, as a ceRNA, is able to sponge miR-205-5p. Moreover, miR-205-5p has been well demonstrated to participate in the regulation of AFAP1 expression and the phenotypes of GC cells, including proliferation, migration and invasion.ConclusionAFAP1-AS1, as a novel biomarker of GC, promotes the proliferation migration and invasion of GC cells and function as ceRNA to target AFAP1 by sponging miR-205-5p.

The effects of gastric cancer interstitial fluid on tumors based on traditional Chinese medicine 'phlegm' theory and the investigation on the mechanism through microRNA-21 regulation.

This study aimed to investigate the effects of gastric cancer interstitial fluid (GCIF) on tumors and explore the possible mechanism of Xiaotan Sanjie decoction (XTSJ) on treatment of gastric cancer from the view of regulating microRNA-21 (miR-21) expression. The GCIF was extracted and identified by measuring the levels of interleukin-8 (IL-8), intercellular adhesion molecule 1 (ICAM-1) and miR-21. The effects of GCIF on the proliferation of SGC-7901 cells and tumor growing were assessed by cell counting kit-8 (CCK-8) assay and subcutaneously transplanted tumor-bearing nude mice model, respectively. Additionally, inhibition effect of XTSJ decoction on proliferation of SGC-7901 cells intervened by GCIF were assessed in vitro and anti-cancer effect of it was further assessed using orthotopic transplanted tumor-bearing nude mice model. The concentration of SGC-7901 gastric cancer cells were dependent on the concentration of the added GCIF. After 72 hours of continuous culture, the interstitial fluid had an obvious proliferative effect on the SGC-7901 tumor cells, which was the most significant in the high concentration group. XTSJ decoction could inhibit the growth-promoting effect (P < 0.01) of GCIF on gastric cancer cells. Intervention of the GCIF might promote the growth (P < 0.05) of the subcutaneously transplanted tumors in nude mice and decrease the net weight of the tumor-bearing nude mice (P < 0.05) after tumor removal. The GCIF was able to up-regulate the expression (P < 0.001) of miR-21 in the subcutaneously transplanted tumors. XTSJ decoction could downregulate the expression (P < 0.05) of miR-21 in SGC-7901 orthotopically transplanted tumors. XTSJ decoction can inhibit the multiplicative effect of GCIF on gastric cancer cells, growth of gastric tumor and promotion effect of GCIF on tumors, probably due to the down-regulating miR-21 expression in tumor tissues.