Beneficial Effects of Gracillin From Rhizoma Paridis Against Gastric Carcinoma via the Potential TIPE2-Mediated Induction of Endogenous Apoptosis and Inhibition of Migration in BGC823 Cells.

Tumor necrosis factor-α inducible protein-8 (TIPE2), initially recognized as a negative immune regulator, exerts an important role in suppressing the progression of numerous cancers. In our previous investigation, we found that TIPE2 expression displayed a decrease or absence in gastric tumor tissue, and the overexpression of TIPE2 suppressed the growth of gastric cancer tumors and cells, demonstrating that TIPE2 could be a potential medicinal target for gastric cancer treatment. However, it's seldomly reported that several medicinal agents or candidates targeted TIPE2 for treating diseases, including gastric cancer. To identify the candidate targeting TIPE2 to fight against gastric cancer, several extractions from traditional natural medicinal plants with anti-tumor functions were employed to screen the active compounds according to bioassay-guided isolation. Interestingly, gracillin, a component from the ethyl acetate extraction of Rhizoma Paridis, was identified to induce the expression of TIPE2 and inhibit the cell proliferation in gastric cancer BGC-823 cells. Furthermore, the underlying mechanisms that restrain gastric cancer were evaluated by clone formation, EdU staining, flow cytometry, and other assays. Meanwhile, the role of TIPE2 in the anti-tumor effect of gracillin was elucidated via the use of siTIPE2 RNA. It was determined that gracillin could fight against gastric cancer cells by inhibiting the cell proliferation participated by the PI3K/AKT pathway and cell cycle arrest, suppressing the EMT pathway-regulating cell migration, and inducing bcl2-associated mitochondrial apoptosis. Additionally, TIPE2 maybe contribute to the benefits of gracillin. These results of the present study are an important step toward the medicinal development of gracillin, and are also of use in understanding the effect of TIPE2 as a potential tumor target.

miR-9-5p Suppresses Malignant Biological Behaviors of Human Gastric Cancer Cells by Negative Regulation of TNFAIP8L3.

BACKGROUND: MicroRNA is essential for the malignant progression of human gastric cancer (GC), which is a leading cause of cancer deaths. However, the mechanism is still not so clear. AIMS: In our present research, we investigated the effect of miR-9-5p in GC. METHODS: We detected miR-9-5p expression in human gastric epithelial cell (GES-1) and GC cells (AGS, BGC-823, MKN-45, and MGC-803), plasma of normal or GC patients, as well as orthotopic xenograft mouse models by real-time PCR. The migration ability was detected by Transwell assays after miR-9-5p mimic or inhibitor transfection in GC cells. RESULTS: Our results showed that miR-9-5p expression in GC cells and plasma was significantly decreased. miR-9-5p inhibited migration of GC cells by regulating TNFAIP8L3 directly. Low expression of miR-9-5p in GC patients hardly suppressed the migration mediated by TNFAIP8L3. CONCLUSIONS: miR-9-5p, as a potential tumor suppressor gene, is closely related to the malignant progression of GC. Exploring the regulation between miR-9-5p and TNFAIP8L3 may provide a novel strategy for GC treatment.

Knockdown of TIPE2 increases the proliferation in lipopolysaccharide-stimulated gastric cancer cells.

BACKGROUND: Gastric cancer (GC) is one of the most common malignant diseases with high morbidity and mortality, especially in Asian countries. During the GC developing progress, TIPE2, a member of TNF-alpha induced protein 8-like (TNFAIP8L) family, may play important roles. However, the molecular mechanisms of TIPE2 contributing to cell proliferation and tumor growth are poorly understood in GC. We performed flow cytometry to detect the cell cycle of TIPE2-knockdown GC cells under lipopolysaccharide (LPS) stimulation. METHODS: We measured TIPE2 expression in tumor samples from 46 human GC patients at mRNA level by Realtime PCR and in 68 pairs of GC tissues at protein level by immunohistochemistry. We established stable TIPE2 knockdown SGC7901 and BGC823 cell lines and performed CCK-8 and EdU proliferation assays under the stimulation of LPS. And then we analyzed AKT, IκBα and ERK phosphorylation levels, as well as cycle related proteins CDK4 and CyclinD3 in the stable TIPE2 knockdown SGC7901 and BGC823 cells. RESULTS: Our present studies indicated that the expression of TIPE2 was significantly decreased in tumor tissues compared to distant mucosa tissues in human GC patients. TIPE2 inhibited proliferation stimulated by LPS in SGC7901 and BGC823 cells. Silencing of TIPE2 significantly decreased cell G0/G1 phase ratio and increased G2/M phase. TIPE2 knockdown SGC7901 and BGC823 cells declined AKT and IκBα phosphorylation. TIPE2's action on GC cell cycle was. CONCLUSIONS: Our results demonstrated that TIPE2 is a novel tumor suppressor gene that inhibits GC growth may mediated via AKT and IκBα phosphorylated activation. We revealed that TIPE2 may effectively interdict neoplasm development, which has potential clinical application values for GC targeted therapies.

TIPE2 inhibits GC via regulation of cell proliferation, apoptosis and inflammation.

Gastric cancer (GC), a type of gastric mucosal epithelium disease caused by common malignant tumors, has become a major threat to human health and survival. Tumor necrosis factor­α­induced protein­8 like­2 (TIPE2) is a negative immune regulatory factor that is selectively expressed in immune organs, immune cells and various epithelial cells and serves an important role in the maintenance of human physiological immune homeostasis. In our preliminary study, we found that the expression of TIPE2 was downregulated or absent in GC tissues compared with normal gastric mucosa tissues, indicating that TIPE2 may play a significant role in the development of GC. To clarify the role of TIPE2 in the progression of human GC and to elucidate the underlying mechanism, the association between TIPE2 and phosphatidylinositol 3­kinase (PI3K)/AKT, the cell cycle, the caspase­related apoptosis pathway and the NF­κB signaling pathway were investigated through western blot and flow cytometric analysis. It was determined that TIPE2 inhibited GC cell proliferation mainly by reducing the expression of phosphorylated AKT and ERK, which caused subsequent inhibition of the PI3K­AKT and Ras­Raf­MEK­ERK1/2 signaling pathways. Additionally, we investigated the relationship between TIPE2 and GC and discovered that TIPE2 inhibited tumor progression via growth, apoptosis and inflammatory pathways. The results of the present study provided a theoretical basis for the development and application of TIPE2 as an antitumor agent.

Inhibitory effect of ARHI on pancreatic cancer cells and NF-κB activity.

The aim of this study was to investigate the effect of aplasia ras homolog member I (ARHI) on proliferation, apoptosis and the cell cycle in the pancreatic cancer cell line PANC-1. The study also aimed to examine the effect of ARHI on the activity of the nuclear factor (NF)-κB and to determine whether ARHI acts as a tumor suppressor in the development of pancreatic cancer by inhibiting the activity of NF-κB. A pIRES2­EGFP­ARHI vector, constructed by reverse transcrition (RT)­PCR, was transiently transfected into the PANC-1 cells and analyzed for the expression of the ARHI protein by western blotting. A MTT assay was used to quantify cell proliferation, and apoptosis was analyzed by flow cytometry. The NF­κB signaling pathway, specifically the pathway using the nuclear phosphorylated p65 isoform, was analyzed by western blotting. Expression of the ARHI protein was detected by western blotting subsequent to the PANC-1 cells being transiently transfected with the pIRES2­EGFP­ARHI construct. Cell proliferation was strongly inhibited in the PANC-1 cells transfected with pIRES2­EGFP­ARHI. The cell cycle assays indicated an increase in the number of cells at the G0/G1 phase and a decrease in the cells at the S phase, but the difference was not significant (P>0.05). Time course studies also indicated a marked increase in the apoptotic index following transient transfection, as well as a gradual decrease in the expression of the nuclear phosphorylated p65 protein. ARHI acts as a tumor suppressor by downregulating the NF­κB signaling pathway, which results in the inhibition of cell proliferation, apoptosis and the cell cycle in the pancreatic tumor PANC-1 cell line.

Activation of nuclear factor-kappa B and effects of pyrrolidine dithiocarbamate on TNBS-induced rat colitis.

AIM: To explore the changes of nuclear factor-kappa B (NF-kappaB) DNA-binding activity, the expression of intercellular adhesion molecule-1 (ICAM-1) regulated by NF-kappaB at various times and to evaluate the effects of pyrrolidine dithiocarbamate (PDTC) on trinitrobenzene sulfonic acid (TNBS)-induced rat colitis. METHODS: TNBS of 0.6 mL was mixed with ethanol of 0.3 mL solution and instilled into the lumen of the rat colon. The rat models were divided into 6 groups, which were killed at 24 h, 3, 7, 14, and 21 d after enema. Colonic inflammation and damage were assessed by macroscopical and histological criteria. Activity of NF-kappaB DNA-binding was analyzed by electrophoresis mobility shift assays (EMSA). Expression of ICAM-1 was detected by in situ hybridization (ISH) and immunohistochemistry (IH). Then various doses of PDTC were injected into rat abdomen 30 min before enema with TNBS/ethanol as pretreatment. The rats were killed 4 h after enema and the colonic inflammation, myeloperoxidase (MPO) activity, malondialdehyde (MDA) level, and DNA-binding activity of NF-kappaB were assessed. Finally, PDTC was injected intraperitoneally after colitis was induced. Changes of morphology were assayed. RESULTS: During the first week, hyperemia, hemorrhage, edema and ulceration of the colonic mucosa appeared with predominant infiltration of leukocytes. Neutrophils, macrophages, lymphocytes infiltrated in mucosa and submucosa 14 d later. Fibroblasts and granuloma-like structures were also obviously seen. The binding activity of NF-kappaB began to increase at 24 h time point and reached a peak at 14 d, then decreased but still was higher than control group at 21 d (P<0.01). Levels of ICAM-1 mRNA and protein significantly elevated at 24 h and the peak was at 21 d. Pretreatment with PDTC could attenuate the development of inflammation but not by reducing NF-kappaB activity. This attenuation of inflammation had a positive relationship with the dose of PDTC. PDTC at the dose of 100 mg/kg had no therapeutic effect after colitis was induced. CONCLUSION: NF-kappaB activation is an important event that may be involved in acute and chronic inflammation development and may contribute to self-protection against early inflammation damage. NF-kappaB also regulates ICAM-1 expression during colonic inflammation. Pretreatment of PDTC may attenuate the inflammation development. But PDTC has no therapeutic effect after the colitis is induced.