Interaction between NFATc2 and the transcription factor Sp1 in pancreatic carcinoma cells PaTu 8988t

Effect of NFATc2- and Sp1-mediated TNFalpha Regulation on the Proliferation and Migration Behavior of Pancreatic Cancer Cells

BACKGROUND/AIM

One in two people will develop a tumor during their lifetime. Adenocarcinoma of the pancreas is one of the most aggressive types of cancer in humans with very poor long-term survival. A central role in the carcinogenesis of pancreatic cancer has been attributed to NFAT transcription factors. Previous studies have identified the transcription factor Sp1 as a binding partner of NFATc2 in pancreatic cancer. Using expression profile analysis, our group was able to identify the tumor necrosis factor TNFalpha as a target gene of the interaction between NFATc2 and Sp1. The present study investigated the effect of TNFalpha over-expression via the transcription factors NFATc2 and Sp1 on the pancreatic cancer cell lines PaTu 8988t and PANC-1.

MATERIALS AND METHODS

Transient transfection of NFATc2, Sp1, and TNFalpha siRNAs and their effects on the expression were investigated with immunoblot. Cell proliferation was measured with the ELISA BrdU assay. Cell migration was assayed with a Cell Migration Assay Kit using a Boyden chamber.

RESULTS

Inhibition of the transfection factors NFATc2, Sp1, or TNFalpha by siRNA significantly inhibited proliferation, which was exacerbated when using the combination of NFATc2 and Sp1. TNFalpha was able to counterbalance this effect. In contrast to proliferation, migration of pancreatic cancer cells was increased by inhibiting these transfection factors.

CONCLUSION

Tumor progression is strongly influenced by transcriptional changes in signaling cascades and oncogene mutations as well as by changes in tumor suppressor genes. Further studies are needed to understand the underlying mechanisms of these processes.

Effects of Ketamine, S-Ketamine and MK 801 on Integrin Beta-3-mediated Cell Migration in Pancreatic Carcinoma

Introduction

Pancreatic ductal adenocarcinoma is one of the most aggressive malignancies in humans. The main reason for its unfavourable prognosis is the combination of rapid tumour growth, early-onset metastasis and currently still inadequate diagnostic and therapeutic options. Thus, only very few patients are eligible for radical resection of the primary tumour as the only curative treatment option available so far. In the perioperative period, tumour progression and metastasis are facilitated by the activation of key signalling pathways and the altered regulation of transcription factors. Various tumour entities have shown increased expression of the integrin-3 receptor subunit, which correlates with more rapid tumour progression and metastasis through advanced migration, invasion and proliferation. The influence of perioperative medication and postoperative pain management remains unclear. To investigate the effects of ketamine, s-ketamine and MK 801 on integrin beta-3-mediated cell migration in pancreatic cancer cells in vitro.

Methods

The effects of ketamine, s-ketamine and MK 801 on integrin beta-3 expression were investigated with immunoblot. Cell migratory potentials were analysed using a Cell Migration Assay Kit with a Boyden chamber, in which cells migrate through a semipermeable membrane under different stimuli.

Results

Stimulation with ketamine and MK 801 significantly promoted migration in pancreatic cancer cells, increasing the expression of integrin beta-3.

Conclusion

Novel therapeutic approaches target the effective modulation of specific signalling and transcription pathways. The prerequisite for such 'target therapies' is comprehensive knowledge about the respective carcinogenesis. Further studies are required to identify the underlying disease mechanisms of pancreatic carcinoma.

The active role of the transcription factor Sp1 in NFATc2-mediated gene regulation in pancreatic cancer

BACKGROUND

Adenocarcinoma of the pancreas is one of the most aggressive tumor diseases affecting the human body. The oncogenic potential of pancreatic cancer is mainly characterized by extremely rapid growth triggered by the activation of oncogenic signaling cascades, which suggests a change in the regulation of important transcription factors. Amongst others, NFAT transcription factors are assumed to play a central role in the carcinogenesis of pancreatic cancer. Recent research has shown the importance of the transcription factor Sp1 in the transcriptional activity of NFATc2 in pancreatic cancer. However, the role of the interaction between these two binding partners remains unclear. The current study investigated the role of Sp1 proteins in the expression of NFATc2 target genes and identified new target genes and their function in cells. A further objective was the domain of the Sp1 protein that mediates interaction with NFATc2. The involvement of Sp1 proteins in NFATc2 target genes was shown by means of a gene expression profile analysis, and the results were confirmed by quantitative RT-PCR. The functional impact of this interaction was shown in a thymidine incorporation assay. A second objective was the physical interaction between NFATc2 and different Sp1 deletion mutants that was investigated by means of immunoprecipitation.

RESULTS

In pancreatic cancer, the proto-oncogene c-Fos, the tumor necrosis factor TNF-alpha, and the adhesion molecule integrin beta-3 are target genes of the interaction between Sp1 and NFATc2. Loss of just one transcription factor inhibits oncogenic complex formation and expression of cell cycle-regulating genes, thus verifiably decreasing the carcinogenic effect. The current study also showed the interaction between the transcription factor NFATc2 and the N-terminal domain of Sp1 in pancreatic cancer cells. Sp1 increases the activity of NFATc2 in the NFAT-responsive promoter.

CONCLUSIONS

The regulation of gene promotors during transcription is a rather complex process because of the involvement of many proteins that - as transcription factors or co-factors - regulate promotor activity as required and control cell function. NFATc2 and Sp1 seem to play a key role in the progression of pancreatic cancer.

Growth Differentiation Factor 11 Promotes Abnormal Proliferation and Angiogenesis of Pulmonary Artery Endothelial Cells

Disordered proliferation and angiogenesis of pulmonary artery endothelial cells is an important stage in the development of pulmonary arterial hypertension. Recent studies revealed that GDF11 (growth differentiation factor 11) induces endothelial cells proliferation and migration; however, whether GDF11 is directly involved in the pathogenesis of pulmonary arterial hypertension remains unknown. Here, we found that GDF11 was significantly upregulated and activated in 2 experimental pulmonary arterial hypertension models and cultured pulmonary artery endothelial cells. Genetic ablation of gdf11 in endothelial cells rescued pulmonary arterial hypertension features, as demonstrated by right ventricle hypertrophy, right ventricular systolic pressure, hemodynamics, cardiac function, and vascular remodeling. Moreover, we found that hypoxia significantly increased cell cycle progression, proliferation, migration, adhesion, and tube formation, which were significantly inhibited by GDF11 small interfering RNA. These events could be reproduced using cultured pulmonary artery endothelial cells and were dependent on Smad signaling. Moreover, hypoxia-induced GDF11 expression was regulated by the transcription factor zinc finger protein 740, which assisted RNA polymerase in recognizing and binding to the GDF11 promoter sequence located at a site (-753/-744; CCCCCCCCAC) upstream of the gene. This study identified a novel growth and differentiation factor signaling pathway involved in the zinc finger protein 740/GDF11/transforming growth factor-β receptor I/Smad signaling axis and involved in pulmonary artery endothelial cells proliferation and angiogenesis. These results provide critical insights for the development of novel therapeutic strategies for pulmonary arterial hypertension involving components of the GDF11 signaling system.