Gastric Cancer BGC-823 Cells Research Articles

Dynamic characterization of drug resistance and heterogeneity of the gastric cancer cell BGC823 using single-cell Raman spectroscopy.

Drug resistance and heterogeneous characteristics of human gastric carcinoma cells (BGC823) under the treatment of paclitaxel (PTX) were investigated using single-cell Raman spectroscopy (RS). RS of normal and drug-resistant BGC823 cells (DR-BGC823) were collected and analyzed using arithmetic, statistic and individual spectrum analysis. The dynamic effects of paclitaxel (PTX) in normal and DR-BGC823 cells were evaluated dynamically. The RS intensity changed with PTX over time and produced distinct different results for the two types of cells. The average RS intensities of the normal BGC823 cells initially decreased and then increased under PTX treatment after 24 hours. In contrast, upon exposure to PTX, the average intensity of the DR-BGC823 cells initially increased within 12 hours and then gradually decreased and approached a steady state. The temporal variation of the typical component in the cells was analyzed by comparing the ratios between Raman bands. More importantly, the heterogeneous characteristics of the BGC823 cells under PTX treatment were quantified and clustered using hierarchical trees combined with RS intensity changes. The 'outlier' cells related to drug resistance were discriminated. The heterogeneity of the normal BGC823 cells under drug treatment gradually appeared over time, and was evaluated with the eigenvalues of principal component analysis (PCA). Our study indicates that single-cell RS may be useful in systematically and dynamically characterizing the drug response of cancer cells at the single-cell level.

Induction of Pro-Inflammatory Response via Activated Macrophage-Mediated NF-κB and STAT3 Pathways in Gastric Cancer Cells

Background/Aims: Chronic inflammation plays an important role in the initiation and progression of gastric cancer (GC). However, the role and relationship of activated macrophages with gastric mucous epithelium cells in initiating and maintaining the inflammatory process during gastric carcinogenesis remains unclear. Methods: The tumour associated macrophages (TAMs) density of gastric cancer was characterized by immunohistochemistry, and the relationship between macrophages and gastric epithelium cells was analysed using an in vitro culture system that imitates the inflammatory microenvironment. The production of pro-inflammatory cytokines was detected by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR (qRT-PCR). MTT assays, Western blotting, qRT-PCR, and luciferase reporter assays were used to detect the effects of cell proliferation, as well as the NF-κB and STAT3 signalling pathways. Results: TAMs infiltrated with a high intensity in GC and were significantly correlated with histology grade (P = 0.012), metastasis (P = 0.001), TNM stage (P = 0.002), and poor prognosis in patients (PFS, P = 0.005; OS, P = 0.028). In addition, IL-6 and IL-8 were elevated in the serum of GC patients and significantly promoted the growth of GC. The exposure of BGC823 gastric cancer cells to a conditioned medium from LPS-treated D-THP-1 cells significantly induced the production of TNF-α, IL-6, IL-1β and IL-8 (P< 0.01). LPS and LPS-treated D-THP-1-conditioned media promoted gastric cancer cell proliferation and triggered the significant activation of NF-κB and STAT3 with a concomitant degradation of IκBα and an increase in JAK2 phosphorylation (P < 0.05). Moreover, gastric cancer cells markedly expressed cell membrane LPS receptors, such as TLR1, TLR4, TLR6, CD14 and MD2. Conclusions: TAMs are closely associated with the growth of GC and prognosis in GC patients. GC cells may directly sustain and amplify the local pro-inflammatory response upon encountering activated macrophages and LPS via NF-κB and STAT3 signalling pathways, thereby promoting tumour progression.

Cancer cell-derived von Willebrand factor enhanced metastasis of gastric adenocarcinoma

Cancer prognosis is poor for patients with blood-borne metastasis. Platelets are known to assist cancer cells in transmigrating through the endothelium, but ligands for the platelet-mediated cancer metastasis remain poorly defined. von Willebrand factor (vWF) is a major platelet ligand that has been widely used as a biomarker in cancer and associated inflammation. However, its functional role in cancer growth and metastasis is largely unknown. Here we report that gastric cancer cells from patients and cells from two well-established gastric cancer lines express vWF and secrete it into the circulation, upon which it rapidly becomes cell-bound to mediate cancer-cell aggregation and interaction with platelets and endothelial cells. The vWF-mediated homotypic and heterotypic cell–cell interactions promote the pulmonary graft of vWF-overexpressing gastric cancer BGC823 cells in a mouse model. The metastasis-promoting activity of vWF was blocked by antibodies against vWF and its platelet receptor GP Ibα. It was also reduced by an inhibitory siRNA that suppresses vWF expression. These findings demonstrate a causal role of cancer-cell-derived vWF in mediating gastric cancer metastasis and identify vWF as a new therapeutic target.

Effect of silencing colon cancer-associated transcript 2 on the proliferation, apoptosis and autophagy of gastric cancer BGC-823 cells.

The role of long non-coding RNAs (lncRNAs) in the carcinogenesis and progression of tumors has been receiving increasing attention. Colon cancer-associated transcript 2 (CCAT2), a type of oncogenic lncRNA, is regarded as a novel biomarker of poor prognosis and metastasis in various types of cancer. However, the molecular contributions of CCAT2 to gastric cancer (GC) progression remain largely unclear. The aim of the present study was to demonstrate the effect of silencing CCAT2 on the biological behavior of GC BGC-823 cells and illustrate the potential underlying molecular mechanisms. A short hairpin RNA interference plasmid pRNAT-U6.1-CCAT2 targeting CCAT2 was successfully constructed. At 48 h after transfection with the interference plasmid, the survival rate of BGC-823 cells was significantly decreased, as determined by the MTT assay. In addition, RT-qPCR results revealed that CCAT2 gene expression was effectively suppressed by the transfection, while POU domain class 5 transcription factor 1B (POU5F1B) gene expression was significantly decreased. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay further revealed that the apoptotic index was significantly higher in the interference group. Western blot analysis also demonstrated that the expression of beclin-1 protein was significantly increased, whereas the expression levels of phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) proteins were downregulated in the interference group. In conclusion, CCAT2 was able to positively regulate the expression of POU5F1B gene. Furthermore, silencing of CCAT2 gene inhibited the proliferation of BGC-823 cells, as well as induced apoptosis and autophagy in BGC-823 cells, by suppression of the PI3K/mTOR signaling pathways.

MicroRNA-429 decreases the invasion ability of gastric cancer cell line BGC-823 by downregulating the expression of heparanase.

The present study aimed to measure the expression of microRNA (miRNA/miR) −429 in gastric cancer and investigate the associated mechanism of action. A total of 30 patients with gastric cancer who received radical or palliative resection at Jining No. 1 People's Hospital between January-October 2016 were included in the present study. Resected gastric cancer and tumor-adjacent tissues were resected. Gastric cancer BGC-823 cells were transfected with miR-429 mimics to induce the overexpression of miR-429, or transfected with small interfering (si)RNA of heparanase (HPSE) for the silencing of HPSE. Reverse transcription-quantitative polymerase chain reaction was used to measure the expression of miR-429 or HPSE mRNA. Western blotting was employed to determine the protein expression of HPSE. Cell-Counting Kit-8 assay was carried out to test cell proliferation and a Transwell assay was used to determine cell invasion ability. Expression of HPSE mRNA and protein in gastric cancer tissues was increased compared with tumor-adjacent tissues. Reduced expression of miR-429 in gastric cancer tissues may be associated with the targeting of HPSE mRNA by miR-429. Overexpression of miR-429 inhibited the transcription and translation of the HPSE gene. However, overexpression of miR-429 did not affect the proliferation of gastric cancer cells. Notably, overexpression of miR-429 reduced the invasion ability of gastric cancer cells. Transfection with HPSE siRNA decreased the expression of the HPSE protein in BGC-823 cells and inhibited the occurrence and development of gastric cancer by reducing the invasion ability of the cells. The present study demonstrated that expression of miR-429 in gastric cancer tissues was significantly reduced compared with tumor-adjacent tissues. As a tumor-suppressor gene, miR-429 decreases the invasion ability of gastric cancer cells by downregulating the expression of HSPE.

Expression of cell adhesion molecule 4 in gastric cancer tissues and its effect on apoptosis, autophagy, invasion and metastasis of human gastric cancer cell line BGC823

Objective To investigate the expression of cell adhesion molecule 4 (CADM4) in gastric cancer tissues and cell lines as well as its effect on apoptosis, autophagy, invasion and metastasis of human gastric cancer cells BGC-823. Methods The expression of CADM4 in 60 cases of gastric cancer tissues and their adjacent tissues was detected by Real-time polymerase chain reaction (PCR). The relationship between CADM4 expression and clinicopathological features of gastric carcinoma was analyzed. The expression of CADM4 was detected in 7 strains of gastric cancer cells (HGC-27, BGC-823, MKN-45, MGC-803, SGC-7901, NCL-N87 and AGS) and the normal gastric mucosa cell line, GES-1, was used as the control. The gastric cancer cells with the lowest level of CADM4 were chosen for the transfection with lentivirus vector of overexpressing CADM4 (LV-CADM4). Real-time PCR was used to detect the expression of CADM4 mRNA in the transfected BGC-823 cells. Flow cytometry was used to detect the cell apoptosis ratio and mitochondrial trans-membrane potential. Transwell invasion assay and cell scratch assay were used to detect the migration and invasion of transfected BGC-823 cells. Western blotting was used to detect the expression of proteins associated with apoptosis, autophagy, invasion and metastasis. Results The relative expression of CADM4 in gastric carcinoma tissues was 0.29±0.03, lower than that (1.20±0.15) of the adjacent tissues (P=0.000). Its expression was related to TNM clinical stage, differentiation, depth of invasion and lymph node metastasis (all P=0.000). The expression level of CADM4 in BGC-823 cells was obviously lower than that in HGC-27, MKN-45, MGC-803, SGC-7901, NCL-N87, AGS and GES-1 cells (P=0.000). As compared with blank control group and negative virus control group, LV-CADM4 promoted the apoptosis of BGC-823 cells and greatly decreased the mitochondrial trans-membrane potential (all P=0.000); meanwhile the expression levels of B cell lymphoma/leukemia-2 (bcl-2), p62 and matrix metalloproteinase (MMP)-9 proteins were down-regulated, and the expression levels of bcl-2 associated X protein (bax), Caspase-9, microtubule-associated protein 1 light chain 3 (LC3) and Beclin1 proteins were up-regulated (all P=0.000). Conclusion The expression of CADM4 was down-regulated in gastric cancer tissues and cells, and up-regulation of CADM4 can induce apoptosis and autophagy via the mitochondrial pathway in BGC-823 cells, and inhibit the invasion and metastasis in BGC-823 cells. Key words: Gastric cancer; Apoptosis; Autophagy; Invasion; Metastasis

Downregulation of liver-intestine cadherin enhances cisplatin-induced apoptosis in human gastric cancer BGC823 cells.

Gastric cancer is the fourth most common type of cancer. Liver-intestine cadherin (CDH17) has been found to be involved in the proliferation and apoptosis of gastric cancer cells. Cisplatin is one of the most widely used antineoplastic agents in the treatment of solid tumor and hematological malignancies. However, the mechanism of enhancing cisplatin-inducing effects on human gastric cancer BGC823 cells by blocking CDH17 gene, both in vitro and in vivo, remains to be clarified. In this study, we investigated the signaling pathway by which cisplatin induces apoptosis by blocking CDH17 gene in gastric cancer BGC823 cells. Our results indicate that down-expression of CDH17 gene can enhance apoptosis-inducing effects of cisplatin on human gastric cancer BGC823 cells. The expression levels of Bax and Cyt-c proteins were upregulated, but the expression levels of Bcl-2 and Bcl-xL proteins were downregulated by blocking CDH17 gene in gastric cancer BGC823 cells after treatment with cisplatin. Moreover, down-expression of CDH17 enhanced the efficacy of cisplatin-induced inhibition of tumor growth in nude mice via apoptosis induction. Down-expression of CDH17 gene can significantly improve apoptosis-inducing effects of cisplatin in vitro and in vivo, which is a new strategy to improve chemotherapeutic effects on gastric cancer.

Effect of metformin on growth of gastric cancer cells SGC7901 and BGC823 and action mechanism

Objective To study the effect of metformin on the proliferation and apoptosis of gastric cancer cells SGC7901 and BGC823, and the possible mechanisms. Methods The effect of metformin on cell proliferation was determined using the cell counting kit-8 (CCK-8) assay. Cell apoptosis and cell cycle were analyzed by flow cytometry. The effect of metformin on the expression of microRNA (miRNA, miR)-let-7a, Cyclin D1, cyclin-dependent kinase (Cdk)2, Cdk4 and p21 was detected by real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting. Results After treatment with different concentrations of metformin (0.5, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0 mmol/L) for 72 h, the growth inhibitory rate of gastric cancer (GC) cell SGC7901 was (15.3±3.1)%, (24.7±6.8)%, (27.3±5.7)%, (31.0±9.6)%, (57.0±3.6)%, (69.0±2.0)% and (70.7±5.9)%, respectively(P=0.000). The growth inhibitory rate of GC cell BGC823 was (37.7±7.5)%, (44.7±2.1)%, (53.7±4.7)%, (59.3±6.4)%, (68.0±5.3)%, (75.7±2.5)% and (81.0±1.0)%, respectively (P=0.000). Metformin inhibited the proliferation of GC cells in a dose-time-dependent manner. The apoptosis rate of SGC7901 in metformin group and control group was (7.68±0.42)% and (2.63±0.72)% (P=0.000), and that of BGC823 in each group was (14.19±0.72)% and (11.31±1.29)% (P=0.028), respectively. Metformin arrested GC cell cycle in G1 phase. In the dosing group, the ratio of gastric cancer cells arresting at G1 phasewas significantly higher than that of the control group, [SGC7901: (57.3±0.6)% vs. (44.2±0.4)% , P=0.000; BGC823: (59.9±1.7)% vs. (52.6±1.7)% , P=0.007]. Metformin upregulated the expression of miR-let-7a, Cyclin D1, Cdk2 and Cdk4, and inhibited the expression of p21. Conclusion Metformin could inhibit the growth of SGC7901 and BGC823 gastric cancer cells by up-regulating the expression of miR-let-7a partly and regulate the cell cycle regulators to arrest the cell cycle progression and promote cell apoptosis. Key words: Metformin; Gastric cancer; MicroRNA; Cell cycle; Apoptosis

Cyclooxygenase-2 mediated synergistic effect of ursolic acid in combination with paclitaxel against human gastric carcinoma.

Ursolic acid (UA) induces apoptosis in gastric cancer cells by inhibiting cyclooxygenase-2 (COX-2). Paclitaxel (PTX) is an important chemotherapy agent used to treat solid tumors. We evaluated the in vitro antitumor activity of UA in combination with PTX against gastric cancer cells and investigated the mechanisms underlying the combined effects. A cytotoxicity test and flow cytometry were utilized to study the effects of UA and PTX on proliferation and apoptosis, respectively. To further elucidate the mechanism, Western blot analysis was used to assess changes in the expression of a series of related proteins, including COX-2, proliferating cell nuclear antigen (PCNA), Bcl-2, and Bax. UA and PTX dose- and time-dependently inhibited BGC-823 and SGC-7901 gastric cancer cell proliferation. Combined delivery of UA and PTX synergistically reduced cell proliferation and induced apoptosis in these cells by lowering COX-2, PCNA, and Bcl-2 expression and by increasing Bax expression. These results indicate that the synergistic inhibition of proliferation and induction of apoptosis by UA and PTX may be induced by reducing COX-2 expression in gastric cancer cells.

Selenoprotein K Mediates the Proliferation, Migration, and Invasion of Human Choriocarcinoma Cells by Negatively Regulating Human Chorionic Gonadotropin Expression via ERK, p38 MAPK, and Akt Signaling Pathway.

Selenoprotein K (SelK), a member of selenoprotein family, is identified as a single endoplasmic reticulum (ER) transmembrane protein. Although over-expression of SelK inhibits adherence and migration of human gastric cancer BGC-823 cells, the effects of SelK in human choriocarcinoma (CCA) are not well understood. In this study, the expression levels of SelK in three CCA cell lines, BeWo, JEG-3, and JAR, were examined. The effects of silencing or over-expressing SelK on expression of human chorionic gonadotropin beta subunit (β-hCG) were detected by western blotting. The results show that the protein level of β-hCG was reciprocally regulated by down- or up-regulation of SelK (*P<0.05; #P<0.05). The proliferative, migratory, and invasive capabilities of JEG-3 cells with reduced or over-expressed SelK were then tested using the cell counting kit-8 (CCK-8), wound healing, and transwell chamber assays. We found that these cellular activities were markedly increased by the loss of SelK in JEG-3 cells. Conversely, over-expressing SelK in JEG-3 cells suppressed these phenotypes. In addition, SelK expression after down- or up-regulation of β-hCG was also measured. Surprisingly, we found that level of SelK was affected by β-hCG (*P<0.05; #P<0.05). The proliferation, migration, and invasion were determined in JEG-3 cells after each over-expression and reduction of β-hCG. The results confirmed that β-hCG functions as a promoter of human choriocarcinoma. Furthermore, ERK/p38 MAPK and Akt signaling pathways were found to involve in these cellular functions. This work suggests that SelK may act as a tumor suppressor in human choriocarcinoma cells by negatively regulating β-hCG expression via ERK, p38 MAPK, and Akt signaling pathways. These findings revealed that selenoprotein K may serve as a novel target for human choriocarcinoma therapy in vitro.

Combination of cecropinXJ and LY294002 induces synergistic cytotoxicity, and apoptosis in human gastric cancer cells via inhibition of the PI3K/Akt signaling pathway.

The aim of the present study was to investigate the cytotoxic and apoptotic effects of cecropinXJ against human gastric cancer BGC823 cells, either alone, or in combination with a specific phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002. Cell viability and the apoptosis rate were measured using flow cytometry with Annexin-V staining. Additionally, the expression levels of several RAC-α serine/threonine kinase (Akt) phosphorylation-associated proteins and apoptosis-regulating proteins were evaluated by western blot analysis. It was observed that the combination of cecropinXJ and LY294002 resulted in significant synergistic cytotoxic and apoptosis effects, as compared with any single agent alone, in a dose-dependent manner. Corresponding to enhanced apoptosis, the expression levels of certain apoptosis-regulating proteins were changed, the most notable being the upregulation of caspase-3, B-cell lymphoma-2 (Bcl-2)-associated death promotor, Bcl-2 homologous antagonist killer, Bcl-2 interacting killer, Bcl-2-like protein 11, Bcl-2-like protein 4 and cytochrome c, and the downregulation of phosphorylated-Bad and Bcl-2 proteins. The present study provided a novel therapeutic regimen for the use of the cecropinXJ in combination with LY294002 for the treatment of gastric cancer.

Retraction Note: Astragalus saponins affect proliferation, invasion and apoptosis of gastric cancer BGC-823 cells

Astragalus memebranaceus is a traditional Chinese herbal medicine used in treatment of common cold, diarrhea, fatigue, anorexia and cardiac diseases. Recently, there are growing evidences that Astragalus extract may be a potential anti-tumorigenic agent. Some research showed that the total saponins obtained from Astragalus membranaceus possess significant antitumorigenic activity. Gastric cancer is one of the most frequent cancers in the world, almost two-thirds of gastric cancer cases and deaths occur in less developed regions. But the effect of Astragalus membranaceus on proliferation, invasion and apoptosis of gastric cancer BGC-823 cells remains unclear. Astragalus saponins were extracted. Cells proliferation was determined by CCK-8 assay. Cell cycle and apoptosis were detected by the flow cytometry. Boyden chamber was used to evaluate the invasion and metastasis capabilities of BGC-823 cells. Tumor growth was assessed by subcutaneous inoculation of cells into BALB/c nude mice. The results demonstrated that total Astragalus saponins could inhibit human gastric cancer cell growth both in vitro and in vivo, in additional, Astragalus saponins deceased the invasion ability and induced the apoptosis of gastric cancer BGC-823 cells. Total Astragalus saponins inhibited human gastric cancer cell growth, decreased the invasion ability and induced the apoptosis. This suggested the possibility of further developing Astragalus as an alternative treatment option, or perhaps using it as adjuvant chemotherapeutic agent in gastric cancer therapy.

Characterization and Purification of Bergamottin from Citrus grandis (L.) Osbeck cv. Yongjiazaoxiangyou and Its Antiproliferative Activity and Effect on Glucose Consumption in HepG2 cells.

Bergamottin is a natural furanocoumarin compound with weak polarity. Characterization and quantification of bergamottin were carried out in different fruit tissues of various citrus cultivars. Among the four citrus tissues tested, i.e., flavedo, albedo, segment membrane (SM), and juice sacs (JS) in eight citrus cultivars, the highest bergamottin content was found in the flavedo of Citrus grandis (L.) Osbeck cv. Yongjiazaoxiangyou (YJZXY, 666.54 μg·g−1 DW). A combination of silica gel column chromatography and high-speed counter-current chromatography (HSCCC) was established to efficiently purify bergamottin from the flavedo of YJZXY. Bergamottin showed significant antiproliferative activity on three cancer cell lines, i.e., human liver cancer HepG2, promyelocytic leukemia HL-60, and gastric cancer BGC-823 cells, which showed a marked inhibition effect on these cell lines in a dose-dependent manner. In addition, bergamottin significantly increased glucose consumption in HepG2 cells also in a dose-dependent manner, which is the first report of its potential in anti-diabetes applications.

Comparison of Different Muscle-Relaxant Anesthetics on Growth, Migration and Invasion of Gastric Cancer Cells

Muscle relaxants, also known as neuromuscular blocking agents, can block nerve impulses to the muscles and are always used in surgery for general anesthesia. However, the effect of muscle-relaxant anesthetics on cell activity in gastric cancer is currently unknown. The present study aimed to examine and compare the role of three different muscle-relaxant anesthetics in gastric cancer cells. Gastric cancer cells (SGC7901 and BGC 823) were treated with a different dose of muscle-relaxant anesthetics, Rocuronium bromide (Rb), Vecuronium bromide (Vb) and Cisatracurium Besilate (CB). Using in vitro models, the effects on gastric cancer cell invasion, growth and migration of various anesthetics were subsequently investigated. We found that Rb increased the growth, invasion and migration of gastric cancer cells SGC7901 and BGC823. However, Vb and CB, as relatively mitigative anesthetics, did not significantly affect gastric cancer cell malignant phenotype at their regular blood concentration. Our results are important in selecting the type and dose of anesthetic used for surgery of gastric cancer patients. An understanding of the effect of muscle-relaxant anesthetics and their impact on tumor metastasis is critical, since it provides insight into the appropriate anesthetic strategy that could improve long-term survival in some patients with gastric cancer.

Identification and characterization of Streptomyces flavogriseus NJ-4 as a novel producer of actinomycin D and holomycin.

This paper is the first public report that Streptomyces flavogriseus can produce both actinomycin D and holomycin. The actinomycete strain NJ-4 isolated from the soil of Nanjing Agricultural University was identified as S. flavogriseus. This S. flavogriseus strain was found for the first time to produce two antimicrobial compounds that were identified as actinomycin D and holomycin. GS medium, CS medium and GSS medium were used for the production experiments. All three media supported the production of actinomycin D, while holomycin was detected only in GS medium and was undetectable by HPLC in the CS and GSS media. The antimicrobial activity against B. pumilus, S. aureus, Escherichia coli, F. moniliforme, F. graminearum and A. niger was tested using the agar well diffusion method. Actinomycin D exhibited strong antagonistic activities against all the indicator strains. Holomycin exhibited strong antagonistic activities against B. pumilus, S. aureus and E. coli and had antifungal activity against F. moniliforme and F. graminearum but had no antifungal activity against A. niger. The cell viability was determined using an MTT assay. Holomycin exhibited cytotoxic activity against A549 lung cancer cells, BGC823 gastric cancer cells and HepG2 hepatocellular carcinoma cells. The yield of actinomycin D from S. flavogriseus NJ-4 was 960 mg/l. S. flavogriseus NJ-4 exhibits a distinct capability and has the industrial potential to produce considerable yields of actinomycin D under unoptimized conditions.

Dysregulated lncRNA-UCA1 contributes to the progression of gastric cancer through regulation of the PI3K-Akt-mTOR signaling pathway.

The long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been recently shown to be dysregulated during disease occurrence and to play an important role in the progression of several cancers. However, the biological role and potential regulation mechanism of UCA1 in the carcinogenesis of gastric cancer remain unclear. In the present study, we found that UCA1 was aberrantly upregulated in gastric cancer tissues and gastric cancer cell lines, and was associated with TNM stage and metastasis. UCA1 silencing significantly inhibited gastric cancer BGC-823 cell proliferation and increased its apoptosis. We also found that UCA1 played an important role in the migration and invasion of gastric cancer cells in vitro and in vivo. The molecular mechanism of UCA1 suggested that UCA1 regulates the PI3K-Akt-mTOR signaling proteins and their downstream mediators, to alter gastric cancer progression in vitro and in vivo. Collectively, the results showed a pivotal role of UCA1 in the tumorigenesis of gastric cancer. In addition, the study characterized a novel lncRNA-mRNA regulatory network, which may lead to a better understanding of the pathogenesis of gastric cancer and assist in lncRNA-directed diagnosis and therapy for this malignancy.

Effects of celecoxib on cell apoptosis and Fas, FasL and Bcl-2 expression in a BGC-823 human gastric cancer cell line.

Fas, which is an apoptotic-related protein, has an important role in cell apoptosis. Fas ligand (FasL) binds to Fas and activates apoptosis signal transduction. We previously demonstrated that the efficiency of celecoxib inhibited the proliferation and apoptosis of HT-29 colon cancer cell line. The BGC823 cell line was used as an experimental model to evaluate the potential role of celecoxib on gastric cancer cell apoptosis. Inhibitory effects of celecoxib on cell viability were determined by MTT assay. Cell apoptosis was evaluated by flow cytometric analysis and laser confocal microscopy. The results of the present study demonstrated that celecoxib inhibited the viability of BGC823 cells in a concentration- and time-dependent manner. Furthermore, the effect of BGC823 cells apoptosis was increased in a concentration-dependent manner. Western blotting was used to determine the protein expression levels of Fas, FasL, and B-cell lymphoma-2 (Bcl-2). During the celecoxib-induced apoptosis of BGC823 cells, celecoxib upregulated Fas expression and downregulated FasL and Bcl-2 expression in a concentration-dependent manner. These results suggest that celecoxib inhibited the growth and induced apoptosis of BGC823 gastric cancer cells by regulating the protein expression of Fas, FasL and Bcl-2.

Antioxidant Capacity, Anticancer Ability and Flavonoids Composition of 35 Citrus (Citrus reticulata Blanco) Varieties.

Citrus (Citrus reticulate Blanco) is one of the most commonly consumed and widely distributed fruit in the world, which is possessing extensive bioactivities. Present study aimed to fully understand the flavonoids compositions, antioxidant capacities and in vitro anticancer abilities of different citrus resources. Citrus fruits of 35 varieties belonging to 5 types (pummelos, oranges, tangerines, mandarins and hybrids) were collected. Combining li quid chromatography combined with electrospray ionization mass spectrometry (LC-ESI-MS/MS) and ultra-performance liquid chromatography combined with diode array detector (UPLC-DAD), a total of 39 flavonoid compounds were identified, including 4 flavones, 9 flavanones and 26 polymethoxylated flavonoids (PMFs). Each citrus fruit was examined and compared by 4 parts, flavedo, albedo, segment membrane and juice sacs. The juice sacs had the lowest total phenolics, following by the segment membrane. Four antioxidant traits including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and cupric reducing antioxidant capacity (CUPRAC) were applied for the antioxidant capacities evaluation. Three gastric cancer cell lines, SGC-7901, BGC-823 and AGS were applied for the cytotoxicity evaluation. According to the results of correlation analysis, phenolics compounds might be the main contributor to the antioxidant activity of citrus extracts, while PMFs existing only in the flavedo might be closely related to the gastric cancer cell line cytotoxicity of citrus extracts. The results of present study might provide a theoretical guidance for the utilization of citrus resources.

Paclitaxel induces autophagy in gastric cancer BGC823 cells

ABSTRACTThis paper explores the connection between paclitaxel, a chemotherapeutic agent, and gastric cancer cells. In this experiment, it is demonstrated that paclitaxel triggers autophagy and inhibits proliferation of gastric cancer cells. An 3–(4,5–dimethyl–2–thiazolyl)–2,5–diphenyl–2–H–tetrazolium bromide (MTT) assay was used to detect cell viability and the IC50 of paclitaxel. Western blot was used to detect the expression levels of P62, and to measure the protein expression of autophagy. Immunofluorescence was used to reveal the appearance of punctate structures in the cytoplasm—this ultrastructure associated with autophagy was observed by microscopy. Electron microscopy revealed the formation of double-membrane autophagosomes, a typical structure of autophagy. In conclusion, our research indicates that paclitaxel may influence gastric cancer BGC823 cells by way of inducing autophagy.

The role of adrenomedullin in the pathogenesis of gastric cancer.

Adrenomedullin has been shown to be overexpressed in many tumors, including gastric cancer tumors; however, its mechanism of action remains unclear. In this study, we examined the role of adrenomedullin in the pathogenesis of gastric cancer. Using clinical specimens and immunohistochemistry, we found that the expression levels of adrenomedullin and its receptors are inordinately elevated as compared to the adjacent non-tumor gastric tissues. We used siRNA gene silencing, in BGC-823 gastric cancer cell lines, to target adrenomedullin genes, and found that increased adrenomedullin expression results in the proliferation of tumor cells, tumor invasion, and metastasis. Furthermore, we found that under hypoxic conditions, gastric cancer BGC-823 cells exhibit higher expression levels of adrenomedullin and various other related proteins. Our results indicate the involvement of adrenomedullin in microvessel proliferation and partially in the release of hypoxia in solid tumors. Knockdown of adrenomedullin expression, at the protein level, reduced the levels of phosphoprotein kinase B and B-cell lymphoma 2 but increased the levels of cleaved-caspase3 and Bcl 2 associated x protein (Bax). Therefore, we hypothesized siRNA targeting of adrenomedullin genes inhibits various serine/threonine kinases via a signaling pathway that induces cell apoptosis. SiRNA targeting of adrenomedullin genes and green fluorescent control vectors were used to transfect BGC-823 cells, and western blot analyses were used to detect changes in the rates of autophagy in related proteins using confocal laser scanning microscopy. No significant changes were detected. Therefore, the knockdown of adrenomedullin and its receptors may represent a novel treatment strategy for gastric cancer.