CD40 signaling activated by agonistic anti-CD40 monoclonal antibody 5C11 has different effects on biological behavior of gastric carcinoma cells

Demethylzeylasteral inhibits proliferation, migration, and invasion through FBXW7/c-Myc axis in gastric cancer

Gastric cancer (GC) is one of the most familiar malignancy in the digestive system. Demethylzeylasteral (Dem), a natural functional monomer extracted from Tripterygium wilfordii Hook F, shows anti‐tumor effects in a variety of cancers, including GC, however, with the underlying mechanism poorly understood. In our study, we show that Dem inhibits the proliferation, migration, and invasion of GC cells, which are mediated by down‐regulating c‐Myc protein levels. Mechanistically, Dem reduces the stability of c‐Myc by up‐regulating FBXW7, an E3 ubiquitin ligase. Moreover, in xenograft tumor model experiment, Dem also inhibits GC, which depends on suppressing c‐Myc expression. Finally, Dem enhances GC cell chemosensitivity to the combination treatment of 5‐Fluorouracil (5‐Fu) and doxorubicin (DOX) in vitro. Together, Dem exerts anti‐neoplastic activities through destabilizing and suppressing c‐Myc, establishing a theory foundation for using it in future treatment of GC.

Raised CD40L expression attenuates drug resistance in Adriamycin-resistant THP-1 cells

Acute myeloid leukemia is a common hematological malignancy that often exhibits strong drug resistance when treated using conventional chemotherapy. Although numerous studies have been carried out to develop methods of overcoming drug resistance, the results have generally been unsatisfactory. CD40 ligand (CD40L) has been shown to improve the sensitivity of cancer cells to drug treatment. In the present study, Adriamycin (ADM)-resistant human monocytic THP-1 cells (THP-1/A cells) were developed by incubating THP-1 cells with increasing concentrations of ADM. Cells were transfected with CD40L vectors to explore the potential involvement of CD40L in regulating multidrug resistance (MDR) in cancer. Cell proliferation and viability were measured using the Cell Counting Kit-8 assay; cell apoptosis was evaluated by flow cytometry, trypan blue staining and caspase-3 activity; and the expression of MDR-associated protein 1 (MRP1) and permeability glycoprotein (P-gp) was analyzed using western blotting. The results revealed that the protein expression levels of MRP1 and P-gp were downregulated by raised CD40L expression and that the combination of raised CD40L expression with daunorubicin (DNR), a drug from which ADM is derived, significantly increased the extent of cell apoptosis, indicating that drug resistance was effectively attenuated by CD40L. Collectively, these results suggested that CD40L may contribute towards reducing DNR resistance in THP-1/A cells.

Role of vascular endothelial growth factor receptor in the pro-proliferation activity of CD40-CD40L in AGS gastric cancer cells

Background: CD40 is a type α-membrane protein of the tumor necrosis factor receptor super-family, and CD40- induced responses may mediate growth and angiogenesis in carcinoma cells. Objectives: Define the effect of CD40 ligation on AGS gastric cancer cell line and the role of vascular endothelial growth factor/vascular endothelial growth factor receptor (VEGF/VEGFR) signals in this process. Methods: We treated AGS cells with 1 μg/mL soluble CD40 ligand (sCD40L) with or without pre-incubation of either anti-VEGF mAb (MAB293) or VEGFR tyrosine kinase inhibitor (SU5416). We determined the growth effects by cell counts or [3H]-thymidine incorporation assay and VEGF levels in cell-free supernatant using enzymelinked immunosorbent assays. Results: The engagement of CD40-induced AGS cells proliferation accompanied by a significant increase autocrine VEGF through PI3K activation (p <0.05), and exogenous VEGF alone had no effect on spontaneous cell growth. SU5416 with a concentration of 8 μM lead to a dramatic decrease in cell survival induced by sCD40L (p <0.05), whereas MAB293 did not have the similar effect (p >0.05). Conclusion: CD40-CD40L interaction promoted AGS cancer cell line proliferation through a VEGFR-dependent signal pathway in the presence of an internal autocrine loop.

CD40 expression and its prognostic significance in human gastric carcinoma

This study aimed to detect the relationship between CD40 (protein and mRNA) expression and human gastric cancer and to determine the prognostic significance of CD40 in gastric cancer patients. We collected 128 cases of gastric cancer specimens, and the expression of CD40 (protein and mRNA) was measured by immunohistochemistry and in situ hybridization. Our study indicated that CD40 is constitutively expressed in human gastric carcinoma tissues. Positive expression of CD40 (protein and mRNA) in gastric cancer tissues was closely related to the tumor TNM stage and the presence of distant metastasis, with CD40 mRNA also being correlated with the presence of lymphatic metastasis. Furthermore, the expression of CD40 (protein and mRNA) is closely related to the prognosis of gastric cancer patients. The expression of CD40 protein and mRNA is positively correlated with the presence of distant (for both protein and mRNA) and lymphatic (for mRNA only) metastasis, and an increased tumor TNM stage in gastric carcinoma. Patients who express low levels of CD40 may have a better prognosis than those who have higher levels of CD40.

The CD40/CD40L system: a new therapeutic target for disease

The role of CD40/CD40 ligand (CD40L) interactions in atherothrombosis, in the response of the immune system to pathogens and in thrombosis is now widely accepted. A role for CD40-CD40L interactions has been identified in atherosclerosis (AS), and such interactions are known to destabilize atherosclerotic plaques by inducing the expression of cytokines, chemokines, growth factors, matrix metalloproteinases and pro-coagulant factors. CD40/CD40L interactions have also been implicated in immune system disorders. Recent studies have suggested that CD40/CD40L interactions regulate oxidative stress and affect various signaling pathways in both the immunological and the cardiovascular systems. Here, we discuss the current drugs that target the CD40/CD40L system, as understanding the roles and regulations of CD40/CD40L-mediated signal pathways by these drugs could facilitate the development of therapeutics that target diverse diseases.

Screening and test of CD40 related signal transduction pathway in AGS cells and construction of gene silencing vector

This study is designed to screen the CD40 related signal transduction pathway in AGS cells and construction of gene silencing vector. Analysis results showed 414 differential genes expression, including upregulation of 209 genes and downregulation of 205 genes. Basing on the ratio of signal in experimental group to signal in control group, 45 genes (38 genes upregulation and seven genes downregulation) with significant (P<0.01) change in expression levels were screened according to the screening standard (signal log ratio≥1 or ≤-1). These genes involved into metabolism, cell cycle and apoptosis, signal transduction and stress response. Furthermore, PI3K mRNA expression level in PI3K siRNA transfected AGS cells was 0.2335±0.0116 72 h after transfection. This value was significantly (P<0.05) lower than that in blank and negative control groups. PI3K protein expression in PI3K siRNA transfected AGS cells was significantly (P<0.05) lower than that in blank and PI3K siRNA/N transfected groups. Therefore, PI3K siRNA gene silencing vector can significantly inhibit PI3K mRNA and protein expression in AGS cells.

Markers CD40, VEGF, AKT, PI3K, and S100 correlate with tumor stage in gastric cancer

BACKGROUND

To better understand gastric cancer occurrence and prognosis, we explored the expression of molecules in the CD40 pathway and their correlation with gastric cancer prognosis.

PATIENTS AND METHODS

We measured the expression of CD40, VEGF, AKT, PI3K, and S100 in gastric cancer tissues and adjacent normal tissues from 128 patients by immunohistochemistry.

RESULTS

The expression of CD40, VEGF, AKT, and PI3K were significantly higher in tumor tissue than in normal tissue, while S100 expression in dendritic cells (DC) was lower. Expression of CD40, VEGF, AKT, and PI3K significantly increased with T stage, while S100 expression decreased with T stage. Lymph node metastasis was associated with low or negative S100 expression. PI3K expression increased with clinical stage, while negative S100 expression was associated with higher clinical stages. Multivariate analysis did not indicate significant associations between any of these markers and recurrence or mortality.

CONCLUSION

The correlation between T stage of gastric cancer and the higher expression of CD40, VEGF, AKT, and PI3K, along with lower S100 expression in DC, may provide insights into future targets for more effective immunotherapy for cancer.

CD40 signal expression in gastric cancer tissue and its correlation with prognosis of gastric cancer patients

CD40 signaling plays a critical role in the survival rate of gastric cancer patients. Tumour samples were collected from 73 patients with who were diagnosed as gastric cancer in general surgery department in the 1st affiliated hospital of Suzhou University between September 2002 and July 2003. All patients had not received radiotherapy and chemotherapy before operation. These patients include 46 male and 27 female. Here we show that CD40 is constitutively expressed in the human gastric carcinoma tissues, and CD40 protein and mRNA positive expression in gastric cancer tissues closely correlated with lymph node metastasis and tumour TNM stage. CD40 positive expression in gastric cancer patients with lymph node metastasis was markedly higher than that in gastric cancer patients without lymph node metastasis. CD40 positive expression in stage III-IV gastric cancer patients was markedly higher than that in stage I-II gastric cancer patients. Moreover, CD40 expression closely correlated with prognosis of gastric cancer patients. Therefore, CD40 was taken as grouping variable, and lymph node metastasis and clinical staging were taken as stratification variables, respectively, further analysis showed that prognosis in gastric cancer patients with lymph node metastasis and CD40 positive expression was markedly worse than that in gastric cancer patients without lymph node metastasis and CD40 negative expression (P = 0.0076). These results suggest that CD40 signaling plays a critical role in the survival of gastric cancer patients.

Gastric cancer cell lines AGS before and after CD40 signal activating

The aim of this study was to investigate the molecular mechanisms underlying the antitumour effects of CD40L through analysing the change of genes expression profile in AGS using Affymetrix Gene Chip. Human gastric carcinoma AGS cells were first incubated with 2 μg/ml sCD40L or equal volume of medium (control) in F12 medium. RNA was isolated from AGS and were reverse transcribed, labeled with digoxigenin-11-dUTP, and then hybridized with Clontech Atlas mouse cDNA expression arrays for comparison. Performing clustering analysis, we found that 7 detected genes were down-regulated and 38 were upregulated as the sCD40L acted on AGS. To further verify the results of gene chip screening, Gene Database was searched, finding that the most significantly up-regulated genes were Gadd45a, c-Jun and Bcl-2, and the most significantly down-regulated genes were Cyclin D1, CDC6, TNFR10B, c-IAP2 and ORC5L. Based upon these findings, the signalling pathways that possibly mediate CD40-induced apoptosis are proposed.