bay-11-7082 and Stomach-Neoplasms

EBV-associated gastric carcinoma (EBVaGC) is a specific subgroup of gastric carcinoma, and the multifunctional transcriptional factor NF-κB may contribute to its tumorigenesis. In this study, we comprehensively characterized NF-κB signaling in EBVaGC using qRT-PCR, western blot, immunofluorescence assays, ELISA, and immunohistochemistry staining. NF-κB-signaling inhibitors may inhibit the growth of EBVaGC cells and induce significant apoptosis. IκBα is a key regulatory molecule, and repression of IκBα can contribute to aberrant NF-κB activation. Overexpression of LMP1 and LMP2A in the EBV-negative GC cell line SGC7901 could inhibit the expression of IκBα and induce NF-κB activation. These findings indicate that the canonical NF-κB signal is constitutively activated and plays an important role in EBVaGC tumorigenesis.

Topics: Carcinogenesis; Carcinoma; Cell Line, Tumor; Cell Proliferation; Epstein-Barr Virus Infections; Epstein-Barr Virus Nuclear Antigens; Gene Expression Regulation, Neoplastic; Herpesvirus 4, Human; Humans; Leupeptins; NF-kappa B; NF-KappaB Inhibitor alpha; Nitriles; RNA, Small Interfering; Signal Transduction; Stomach Neoplasms; Sulfones; TNF Receptor-Associated Factor 1; Viral Matrix Proteins

NF-κB is a critical target for cancer treatment due to its central role in facilitating cancer progression and desensitizing cancer cells to chemotherapeutic drugs. In this study, a series of chemically modified asymmetric curcuminoid analogs named S01-S15 were synthesized and evaluated for NF-κB inhibitory activity in gastric cancer cell lines. Cell growth inhibition assays revealed that most of these analogs effectively inhibited the growth of BGC-823, SGC-7901, and MFC cells. S06 was selected for further research. MTT assay, clonogenic assay, Hoechst 33258 staining assay, and western blotting revealed that S06 could exert anti-gastric cancer effects by downregulating NF-κB activity. Moreover, via its effects on NF-κB, S06 effectively enhanced the sensitivity of the gastric cancer cells to irinotecan. Together, this study provide a series of new curcuminoid analogs as promising cancer therapeutic agents.

Topics: Antineoplastic Agents; Camptothecin; Cell Proliferation; Curcumin; Dose-Response Relationship, Drug; Down-Regulation; Drug Screening Assays, Antitumor; Humans; Irinotecan; Molecular Structure; NF-kappa B; Stomach Neoplasms; Structure-Activity Relationship; Tumor Cells, Cultured

Helicobacter pylori has been identified as one of the major causes of chronic gastritis, gastric and duodenal ulcers, and gastric cancer. Lipopolysaccharide (LPS) is a major component of the outer membrane of gram-negative bacteria, and H. pylori LPS might play an exclusively important role in activating inflammatory pathways in monocytes and macrophages. To study the role of LPS in the underlying mechanism of inflammatory responses, we established an in vitro model using the human AGS gastric cancer cell line. We found that LPS mediates inflammation through setting off a cascade of events: activation of the store-operated calcium (SOC) channel, initiation of downstream NF-κB signaling, and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). Phosphorylated ERK1/2 promotes the nuclear translocation of NF-κB, and eventually elevates the expression level of COX-2, a major inflammatory gene.

Topics: Calcium; Calcium Channel Blockers; Calcium Channels; Cell Line, Tumor; Chelating Agents; Cyclooxygenase 2; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation, Neoplastic; Humans; Lipopolysaccharides; Models, Biological; NF-kappa B; Nitriles; ORAI1 Protein; Phosphorylation; Promoter Regions, Genetic; Stomach Neoplasms; Stromal Interaction Molecule 1; Sulfones; Time Factors

The ribonucleotide reductase M2 subunit (RRM2) plays an active role in tumor progression and is frequently overexpressed in cancer. It plays a significant role in the regulation of cell invasiveness, cell migration and tumor metastasis. Elevated RRM2 expression has been reported to be associated with poor prognosis of gastric cancer. However, the molecular mechanisms of RRM2 in gastric cancer cells remain elusive. In our study, we found that RRM2 highly expressed in gastric cancer cells BGC823. RRM2 stimulation dose-dependently enhanced the invasion and migration of BGC823 cells. Furthermore, we found that the expressions of MMP-2 and MMP-9 in BGC823 cells were significantly increased after RRM2 stimulation. In addition, RRM2 time-dependently induced activation of AKT, IKBα, and NF-κB. These effects of RRM2 were prevented by AKT selective inhibitor GSK690693 as well as NF-κB selective inhibitor BAY117082. In conclusion, our findings establish a signaling role for RRM2 in gastric cancer cells and identify that the RRM2/AKT/NF-κB signaling pathway is essential for tumor invasiveness in gastric cancer cells. Thus, our data may provide knowledge for using RRM2 as a novel target for effective diagnosis and treatment of gastric cancer.

Topics: Cell Line, Tumor; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Neoplasm Invasiveness; NF-kappa B; Nitriles; Oxadiazoles; Proto-Oncogene Proteins c-akt; Ribonucleoside Diphosphate Reductase; Signal Transduction; Stomach Neoplasms; Sulfones; Time Factors

Inhibitors of nuclear factor (NF)-κB pathway have shown potential anti-tumor activities. However, it is not fully elucidated in gastric cancer.. Firstly, we screened the inhibitory effect of pharmacologic NF-κB inhibitors on cell viability of human gastric cancer cells via CCK-8 assay. Next, cell apoptosis, cell cycle distribution, and mitochondrial membrane potential after BAY 11-7082 treatment were detected by annexin V staining, propidium iodide staining, TUNEL, and JC-1 assays in human gastric cancer HGC-27 cells. Expression of regulatory factors for apoptosis and cell cycle were measured by western blot. Finally, human gastric cancer xenograft model was established to verify the anti-tumor effects of BAY 11-7082 in vivo. Cellular apoptosis and growth inhibition in subcutaneous tumor section were detected by TUNEL and immunohistochemistry assays.. BAY 11-7082 exhibited rapid and potent anti-tumor effects on gastric cancer cells in vitro within a panel of NF-κB inhibitors. BAY 11-7082 induced rapid apoptosis in HGC-27 cells through activating the mitochondrial pathway, as well as down-regulation of Bcl-2 and up-regulation of Bax. BAY 11-7082 also induced S phase arrest through suppressing Cyclin A and CDK-2 expression. Xenograft model confirmed the anti-tumor effects of BAY 11-7082 on apoptosis induction and growth inhibition in vivo.. Our results demonstrated that BAY 11-7082 presented the most rapid and potent anti-tumor effects within a panel of NF-κB inhibitors, and could induce cellular apoptosis and block cell cycle progression both in vitro and in vivo, thus providing basis for clinical application of BAY 11-7082 in gastric cancer cases.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; In Situ Nick-End Labeling; Male; Mice; Mice, Inbred BALB C; Mice, Nude; NF-kappa B; Nitriles; S Phase Cell Cycle Checkpoints; Stomach Neoplasms; Sulfones; Up-Regulation; Xenograft Model Antitumor Assays

The gastric pathogen, helicobacter pylori (H. pylori), has been associated with the progression of gastric cancer. It was previously reported that H. pylori induced urokinase plasminogen activator receptor (uPAR) expression and stimulated cell invasiveness in human gastric cancer AGS cells. However, the precise mechanisms for how H. pylori upregulates uPAR are unclear. This study investigated the underlying signal pathways in H. pylori-induced uPAR in human gastric cancer AGS cells. The intracellular H2O2 content, as determined using H2O2-sensitive probe 2',7'-dichlorodihydrofluorescein, increased after the H. pylori treatment. N-acetyl cysteine (NAC), an antioxidant, prevented the H. pylori-induced production of H2O2 and uPAR expression. In addition, exogenous H2O2 was found to increase uPAR mRNA expression and its promoter activity. Site-directed mutagenesis of the potential NF-kappaB element in the uPAR promoter showed that the redox-sensitive transcription factor NF-kappaB was essential for H. pylori-induced uPAR expression. The expression of vectors encoding a mutated-type NF-kappaB-inducing kinase and I-kappaB, and a specific inhibitor of NF-kappaB (BAY11-7082) decreased the H. pylori-induced uPAR promoter activity. Chromatin immunoprecipitation and the electrophoretic mobility shift assay confirmed that H. pylori increased the DNA binding activity of NF-kappaB. With the aid of NAC and H2O2, it was determined that reactive oxygen species (ROS) is an upstream signaling molecule for activating the NF-kappaB induced by H. pylori. The enhanced AGS cell invasiveness by H. pylori was partially abrogated by an NAC and BAY11-7082 treatment. These results suggest that the ROS and NF-kappaB signaling pathway is important in H. pylori-induced uPAR expression and the increased cell invasiveness of human gastric cancer AGS cells.

Topics: Acetylcysteine; Carcinoma; Free Radical Scavengers; Helicobacter pylori; Humans; Neoplasm Invasiveness; NF-kappa B; Nitriles; Reactive Oxygen Species; Receptors, Cell Surface; Receptors, Urokinase Plasminogen Activator; Signal Transduction; Stomach Neoplasms; Sulfones; Tumor Cells, Cultured