Melittin induces human gastric cancer cell apoptosis via activation of mitochondrial pathway.

Cochinchina momordica seed is the dried ripe seed of Momordica cochinchinensis (Lour.) Spreng, which is a kind of fruit and consumed for dietary as well as medicinal uses. In this study, using the human SGC7901 and MKN-28 gastric cancer cell lines, we explored the anticancer activity of the extract from cochinchina momordica seed (ECMS). ECMS inhibited significantly the survival rates of SGC7901 and MKN-28 cells in concentration- and time-dependent manners by MTT assay. The typical apoptotic morphological changes were observed by Hoechst 33258 dye assay after SGC7901 and MKN-28 cells were treated with ECMS for 48 h. Flow cytometry analysis revealed that ECMS-treatment blocked the cells at the S phase of cell cycle. Furthermore, the protein expression levels of poly (ADP-ribose) polymerase (PARP) and Bcl-2 were downregulated notably by ECMS-treatment, whereas those of Fas/Fas-associated death domain, p53, and Bax were upregulated in SGC7901 cells. ECMS dramatically enhanced the enzymatic activities of caspase-3 and caspase-9 whilst slightly increased caspase-8 activity. Taken together, this study demonstrated that ECMS exerted cytotoxic activities via PARP and p53 signal pathways in the human gastric cancer cells.

Rosiglitazone Reverses Mitomycin C Resistance in Human Gastric Cancer Cells

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

Antitumor activity of Xiaoaiping injection on human gastric cancer SGC-7901 cells

Xanthohumol induces apoptosis via caspase activation, regulation of Bcl-2, and inhibition of PI3K/Akt/mTOR-kinase in human gastric cancer cells

Background. The EGF receptor (EGFR) kinase family plays important role in tumour growth and progression and has been a validated therapeutic target for lung cancers. Here, we examined the activity of an irreversible pan-HER tyrosine kinase inhibitor, neratinib, on kinase phosphorylation and cellular response in human gastric cancer. The study also examined the expression of the neratinib responsive kinases in relation to chemoresistance in human gastric cancer. Method. Tumour and normal gastric tissues from a cohort of 85 patients were obtained along with clinical outcome and therapeutic response to chemotherapy. The level of expression of a panel of protein kinases of interest, including EGFR family members, was quantitatively analysed using a protein based kinase array. Human gastric cancer cells (AGS and HGC27) were assessed for their sensitivity to neratinib, inhibitors of other candidate kinases and combinations thereof. Cellular growth, migration and matrix adhesiveness were evaluated using multiple in vitro platforms. Result. We identified a panel of kinases that were highly responsive to the treatment by neratinib in cell lines. In the gastric cancer cohort, expression of these kinases significantly correlated with the overall survival of the patients (p<0.001) and, together with node involvement, invasion, staging and type of surgery, was an independent prognostic indicator for the clinical outcome. Expression of the EGFR kinase family members EGFR, HER2, and HER4 was linked to poor clinical outcome. Expression of both neratinib response kinases and EGFR family members was also associated with therapeutic resistance to chemotherapies in the cohort of patients analyzed. In vitro, neratinib caused a concentration dependent inhibition of migration, matrix adhesiveness and growth in human gastric cancer cells. The migratory pace of the gastric cancer cells was particularly sensitive to neratinib. The role of two neratinib response kinases, Protein Kinase C iota (PKCi) and Mouse Double Minute 2 homologue (MDM2), was then further investigated. Interestingly, both PKCi and MDM2 were aberrantly expressed in gastric cancer tissues. In addition, the PKCi inhibitor Oncrasin-1 and the MDM2 antagonist Nutlin-3 both demonstrated synergy with neratinib in inhibiting adhesiveness and migration of the gastric cancer cells. Conclusion. Our data indicates that EGFR family members and other neratinib responsive kinases are aberrantly expressed in human gastric cancer and may be of prognostic value for the patients. In addition, gastric cancer cells are sensitive to neratinib, and displayed reduced migration when combined with inhibitors of PKCi or MDM2, two of the neratinib responsive kinases. Citation Format: W. G. Jiang, Tracey A. Martin, Sioned Owen, Lin Ye, Andrew J. Sanders, Yuxin Cui, Meng Xie, Shiqin Jia, Yongning Jia, Fiona Ruge, Francesca Avogadri-Connors, Alshad S. Lalani, Richard P. Bryce, Jiafu Ji. Investigating the activity of neratinib in human gastric cancer and gastric cancer cells, implications on clinical outcome and chemotherapy resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 879.

To elucidate whether human primary gastric cancer and gastric mucosa epithelial cells in vitro can grow normally in a methionine (Met) depleted environment, i.e. Met-dependence, and whether Met-depleting status can enhance the killing effect of chemotherapy on gastric cancer cells. Fresh human gastric cancer and mucosal tissues were managed to form monocellular suspensions, which were then cultured in the Met-free but homocysteine-containing (Met(-)Hcy(+)) medium, with different chemotherapeutic drugs. The proliferation of the cells was examined by cell counter, flow cytometry (FCM) and microcytotoxicity assay (MTT). The growth of human primary gastric cancer cells in Met(-)Hcy(+) was suppressed, manifested by the decrease of total cell counts [1.46 +/- 0.42 (x 10(9).L(-1)) in Met(-)Hcy(+) vs 1.64 +/-0.44(x 10(9).L(-1)) in Met(+)Hcy(-), P<0.01], the decline in the percentage of G(0)G(1) phase cells (0.69 +/- 0.24 in Met(-)Hcy(+) vs 0.80 +/- 0.18 in Met(+)Hcy(-), P<0.01) and the increase of S cells (0.24 +/- 0.20 in Met(-)Hcy(+) vs 0.17 +/- 0.16 in Met(+)Hcy(-), P<0.01); however, gastric mucosal cells grew normally. If Met(-)Hcy(+) medium was used in combination with chemotherapeutic drugs, the number of surviving gastric cancer cells dropped significantly. Human primary gastric cancer cells in vitro are Met-dependent; however, gastric mucosal cells have not shown the same characteristics. Met(-)Hcy(+) environment may strengthen the killing effect of chemotherapy on human primary gastric cancer cells.

The muscarinic receptor M3 is an acetylcholine receptor that regulates the activity of numerous fundamental central and peripheral nervous system functions. Recent studies have identified the activation of the M3 receptor in several cancers; however, the role of M3 in human gastric cancer (GC) remains largely unknown. In this study, we demonstrated that the M3 receptor was overexpressed in human GC tissues and was correlated with the cancer stage and with lymph node metastasis. In vitro, the M3 receptor enhanced the proliferation induced by acetylcholine in human GC cells, whereas the knockdown of M3 by a small hairpin RNA (shRNA) inhibited cell proliferation. Furthermore, M3 knockdown caused G2/M phase cell cycle arrest and induced apoptosis in human GC cells. In vivo, M3 knockdown suppressed tumorigenesis and promoted apoptosis in GC xenografts. In addition, we also detected the secretion of acetylcholine (ACh) by human GC cells and observed the co-expression of the M3 receptor and choline acetyltransferase (ChAT), the enzyme necessary for acetylcholine synthesis, in human GC tissues and cells. Taken together, our findings support an oncogenic role for the M3 receptor in gastric cancer, suggesting that M3 antagonists may serve as potential adjuvants to GC therapies. Further study of the underlying molecular mechanism could also lead to the identification of novel therapeutic targets for improved treatment of GC.

The purpose of this study was to investigate the effect and mechanism of Vav3 gene on the proliferation of human gastric cancer cell line SGC7901. The expressions of Vav3 proten in gastric cancer tissue, tumor-adjacent tissue, human gastric cancer cell line SGC7901 and gastric epithelial cell line GES-1 cells were tested by Western blot. Vav3-siRNA was transfected into the SGC7901 cells. The proliferation of SGC7901 cells in vitro was measured by MTT assay. Cell cycle of SGC7901 cells was determined by flow cytometry.The expressions of proliferation-related genes PCNA, p16, cyclin D1, Rb were determined by qPCR and Western blot assay. Orthotopic transplantation nude mouse models of gastric cancer were prepared, and the tumor growth and expressions of PCNA, P16, cyclin D1, and Rb proteins were examined. The relative expressions of Vav3 in the gastric cancer and peritumoral tissue were 0.910±0.242 and 0.243±0.045, respectively; the relative expressions of Vav3 in SGC7901 and GSE-1 cells were 0.925±0.127 and 0.277±0.038, respevtively (both P<0.05). The expression of Vav3 protein in SGC7901 cells was effectively inhibited by Vav3-siRNA. Proliferation of SGC7901 cells was inhibited by (83.43±10.17)% after 80 nmol/L Vav3-siRNA transfection (P<0.05). The ratio of SGC7901 cells in G0/G1 phase was increased, and in S phase decreased after Vav3-siRNA transfection (both P<0.05). The expressions of PCNA and cyclin D1 were decreased in cells after Vav3-siRNA transfection, and expressions of p16 and Rb were increased after Vav3-siRNA transfection (P<0.05 for all). The tumor growth in the Vav3-siRNA group was much slower than that in the other 2 control groups of nude mouse models. Compared with the two control groups, expressions of PCNA and cyclin D1 were significantly lower in the Vav3-siRNA group, while expressions of p16 and Rb were increased (P<0.05 for all). Vav3 can promote the proliferation of gastric cancer cells by regulating proliferation-related genes.

BackgroundChemoresistance contributes to treatment failure of gastric cancer (GC) patients but the molecular mechanism of chemoresistance in GC is still unclear. Long-chain noncoding RNA (lncRNA) urothelial cancer associated 1 (UCA1) is associated with resistance to chemotherapy drugs.MethodsWe detected the expression of UCA1 in 53 pairs of GC tumor tissue and adjacent normal tissue, human normal gastric mucosa cells (GES-1) and human GC cells (HGC-27, SNU-5, AGS, SGC-7901, and NCI-N87) using RT-qPCR. Small RNA interference technology was used to knock down the expression of UCA1 in gastric cancer cells. CCK8 solution was used to detect cell viability. Flow cytometry was used to detect apoptosis, and Western blotting was used to detect protein expression.ResultsUCA1 was highly expressed in GC tissues and cells, and knockdown of UCA1 increased chemosensitivity to cisplatin by inducing cell apoptosis. Furthermore, UCA1 promoted CYP1B1 expression by binding to miR-513a-3p in human GC cells in vitro, and UCA1/CYP1B1 expression was negatively related to miR-513a-3p expression, while UCA1 expression was positively related to CYP1B1 expression in human GC tissues. Moreover, overexpression of miR-513a-3p or knockdown of CYP1B1 increased chemosensitivity to cisplatin, and knockdown of miR-513a-3p or overexpression of CYP1B1 decreased chemosensitivity to cisplatin by inducing cell apoptosis in human GC cells. Importantly, overexpression of CYP1B1 reduced chemosensitivity to cisplatin which increased by knockdown of UCA1, and knockdown of CYP1B1 increased chemosensitivity to cisplatin which decreased by knockdown of miR-513a-3p in human GC cells.ConclusionThe lncRNA UCA1/miR-513a-3p/CYP1B1 axis regulates cisplatin resistance in human GC cells; hence, it is a potential target for treating chemoresistance in GC.

To investigate the effects and underlying mechanisms of plumbagin, a naphthoquinone derived from medicinal plant Plumbago zeylanica, on human gastric cancer (GC) cells. Human gastric cancer cell lines SGC-7901, MKN-28, and AGS were used. The cell viability was examined using CCK-8 viability assay. Cell proliferation rate was determined using both clonogenic assay and EdU incorporation assay. Apoptosis was detected via Annexin V/propidium iodide double-labeled flow cytometry. Western blotting was used to assess the expression of both NF-κB-regulated gene products and TNF-α-induced activation of p65, IκBα, and IKK. The intracellular location of NF-κB p65 was detected using confocal microscopy. Plumbagin (2.5-40 μmol/L) concentration-dependently reduced the viability of the GC cells. The IC(50) value of plumbagin in SGC-7901, MKN-28, and AGS cells was 19.12, 13.64, and 10.12 μmol/L, respectively. The compound (5-20 μmol/L) concentration-dependently induced apoptosis of SGC-7901 cells, and potentiated the sensitivity of SGC-7901 cells to chemotherapeutic agents TNF-αand cisplatin. The compound (10 μmol/L) downregulated the expression of NF-κB-regulated gene products, including IAP1, XIAP, Bcl-2, Bcl-xL, tumor factor (TF), and VEGF. In addition to inhibition of NF-κB p65 nuclear translocation, the compound also suppressed TNF-α-induced phosphorylation of p65 and IKK, and the degradation of IκBα. Plumbagin inhibits cell growth and potentiates apoptosis in human GC cells through the NF-κB pathway.

Sesquiterpenoids are a major type of compound found in Solanum lyratum (S. lyratum). The present study aimed to investigate whether sesquiterpenoids from S. lyratum demonstrated cytotoxicity against the MCF-7, HCT-8, A-549, SGC-7901 and BEL-7402 cell lines, and the mechanism of solajiangxin H and lyratol D, which exhibited high cytotoxicity against SGC-7901 cells (half maximal inhibitory concentration, IC50=4.8 and 5.9 µg/ml), was associated with mitochondria-mediated apoptosis. The results of the Cell Counting Kit-8 assay indicated that 15 sesquiterpenoids had cytotoxicity against the aforementioned cultured cells. The results of DAPI staining and western blot analysis, used to study the anticancer mechanisms of solajiangxin H and lyratol D in SGC-7901 cells, suggested that solajiangxin H and lyratol D induced the apoptosis of SGC-7901 cells significantly (P<0.01), downregulated the expression of the antiapoptotic proteins B-cell lymphoma (Bcl)-2 and survivin, and upregulated the expression of the proapoptotic proteins Bcl-2-like protein 4, second mitochondria-derived activator of caspase, cleaved (c)-caspase-3 and c-caspase-9. The present study therefore demonstrated that 15 sesquiterpenoids from S. lyratum exhibited anticancer activity in MCF-7, HCT-8, A-549, SGC-7901 and BEL-7402 cells, and that the anticancer mechanisms of solajiangxin H and lyratol D may be associated with mitochondria-mediated apoptosis. Additionally, the present study provides evidence in support of the hypothesis that S. lyratum may be a promising candidate for the development of novel cancer therapies.

This study aims to investigate the effect of ethoxysanguinarine(Eth) on cisplatin(DDP)-resistant human gastric cancer cells and decipher the underlying mechanism. The human gastric cancer cell line SGC7901 and the DDP-resistant cell line SGC7901/DDP were used as the cell models. Western blot was employed to determine the expression levels of multidrug resistance-related proteins, and methyl thiazolyl tetrazolium(MTT) assay to detect the proliferation of SGC7901 and SGC7901/DDP cells exposed to DDP. After treatment with different concentrations of Eth, the proliferation of SGC7901 and SGC7901/DDP cells was detected by MTT assay, trypan blue exclusion assay, colony formation assay, and high-content imaging and analysis system. The apoptosis of SGC7901/DDP cells was detected by flow cytometry with Annexin V-FITC/PI staining. GFP-LC3 transfection was carried out to detect the effect of Eth on the autophagy of SGC7901/DDP cells. The expression levels of the multidrug resistance-related protein P-glycoprotein(P-gp), the apoptosis-related proteins [caspase-9, caspase-3, and poly(ADP-ribose) polymerase(PARP)], the autophagy-related protein light chain 3-Ⅱ(LC3-Ⅱ), the key effectors [mammalian target of rapamycin(mTOR), 70 kDa ribosomal protein S6 kinase(P70 S6 K), and 4 E binding protein 1(4 E-BP1)] of the mammalian target of rapamycin complex 1(mTORC1) signaling pathway, cancerous inhibitor of protein phosphatase 2A(CIP2A), and protein kinase B(Akt) were measured by Western blot. The mRNA level of CIP2A in the SGC7901/DDP cells exposed to Eth for 24 h was analyzed by RT-qPCR. After SGC7901/DDP cells were transfected with CIP2A expression vector pcDNA3.1-HA-CIP2A and treated with different concentrations of Eth, MTT assay was used to determine the prolife-ration of SGC7901/DDP cells and Western blot to detect the expression levels of related proteins. The interaction sites of Eth and CIP2A were predicted by molecular docking. The affinity between Eth and CIP2A was determined by drug affinity responsive target stability(DARTS) assay. The pharmacokinetic properties and drug-like activity of Eth were predicted by SwissADME. The results indicated that SGC7901/DDP cells were more sensitive to Eth than SGC7901 cells. Eth significantly inhibited proliferation and colony formation and changed the morphology, roundness, and area of SGC7901/DDP cells. Eth treatment caused the nucleus shrinking and significantly increased the apoptosis rate of the cells. Furthermore, Eth down-regulated the expression of caspase-9 and caspase-3 precursors and promoted the cleavage of PARP, which suggested that Eth induced the apoptosis of SGC7901/DDP cells. The GFP-LC3 in Eth-treated cells showed speckled aggregation. The up-regulated expression of LC3-Ⅱ by Eth indicated that Eth activated the autophagy of SGC7901/DDP cells. Eth down-regulated the expression of P-gp, the phosphorylation of mTOR, P70 S6K, and 4E-BP1, the expression of CIP2A, and the phosphorylation of Akt. Additionally, it increased the activity of PP2A, and had no significant effect on the expression of CIP2A in SGC7901/DDP cells. CIP2A overexpression antagonized the inhibition of cell proliferation and the activation of autophagy by Eth. Molecular docking suggested that Eth bound to CIP2A. The results of DARTS assay further proved the above binding effect. Eth has potential drug-like activity. The above results demonstrated that Eth inhibited the proliferation, induced the apoptosis, and activated the autophagy of SGC7901/DDP cells by targeting CIP2A and then down-regulating PP2A/mTORC1 signaling pathway. This study provided a new target for the treatment of cisplatin-resistant gastric cancer.

Evaluate the possible value of FasL in gastric cancer gene therapy by investigating the effects of FasL expression on human gastric cancer cell line.An adenoviral vector encoding the full-length human FasL cDNA was constructed and used to infect a human gastric cancer (SGC-7901) cell line. FasL expression was confirmed by X-gal staining, flow cytometric analysis and RT-PCR. The effect of FasL on cell proliferation was determined by clonogenic assay, cytotoxicity was detected by MTT assay, and cell viability was measured by trypan blue exclusion. The therapeutic efficiency of Ad-FasL in in vivo was investigated with a xenograft tumor model in nude mice.SGC-7901 cells infected with Ad-FasL showed increased expression of FasL, resulting in significantly decreased cell growth and colony-forming activity when compared with control adenovirus-infected cells. The cytotoxicity of anti-Fas antibody (CH-11) in gastric cancer cells was stronger than that of ActD (91plusmn8 vs 60plusmn5, P<0.01), and the cytotoxicity of Ad-FasL was stronger than that of CH-11 (60plusmn5 vs 50plusmn2, P<0.05). In addition, G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> -phase arrest (67.75plusmn0.39 vs 58.03plusmn2.16, P<0.05) and apoptosis were observed in Ad-FasL-infected SGC-7901 cells, and the growth of SGC-7901 xenografts in nude mice was retarded after intra-tumoral injection with Ad-FasL (54% vs 0%, P<0.0001).Infection of human gastric carcinoma cells with Ad-FasL induces apoptosis, indicating that this target gene might be of potential value in gene therapy for gastric cancer.

To evaluate the possible value of FasL in gastric cancer gene therapy by investigating the effects of FasL expression on human gastric cancer cell line. An adenoviral vector encoding the full-length human FasL cDNA was constructed and used to infect a human gastric cancer (SGC-7901) cell line. FasL expression was confirmed by X-gal staining, flow cytometric analysis and RT-PCR. The effect of FasL on cell proliferation was determined by clonogenic assay, cytotoxicity was detected by MTT assay, and cell viability was measured by trypan blue exclusion. The therapeutic efficiency of Ad-FasL in vivo was investigated with a xenograft tumor model in nude mice. SGC-7901 cells infected with Ad-FasL showed increased expression of FasL, resulting in significantly decreased cell growth and colony-forming activity when compared with control adenovirus-infected cells. The cytotoxicity of anti-Fas antibody (CH-11) in gastric cancer cells was stronger than that of ActD (91+/-8 vs 60+/-5, P<0.01), and the cytotoxicity of Ad-FasL was stronger than that of CH-11 (60+/-5 vs 50+/-2, P<0.05). In addition, G1-phase arrest (67.75+/-0.39 vs 58.03+/-2.16, P<0.05) and apoptosis were observed in Ad-FasL-infected SGC-7901 cells, and the growth of SGC-7901 xenografts in nude mice was retarded after intra-tumoral injection with Ad-FasL (54% vs 0%, P<0.0001). Infection of human gastric carcinoma cells with Ad-FasL induces apoptosis, indicating that this target gene might be of potential value in gene therapy for gastric cancer.