scholarly journals Hyperglycemia Promotes the Epithelial-Mesenchymal Transition of Pancreatic Cancer via Hydrogen Peroxide

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Li ◽  
Lun Zhang ◽  
Xin Chen ◽  
Zhengdong Jiang ◽  
Liang Zong ◽  
...  

Diabetes mellitus (DM) and pancreatic cancer are intimately related, as approximately 85% of patients diagnosed with pancreatic cancer have impaired glucose tolerance or even DM. Our previous studies have indicated that high glucose could promote the invasive and migratory abilities of pancreatic cancer cells. We therefore explored the underlying mechanism that hyperglycemia modulates the metastatic potential of pancreatic cancer. Our data showed that streptozotocin- (STZ-) treated diabetic nude mice exhibit larger tumor size than that of the euglycemic mice. The number of nude mice that develop liver metastasis or ascites is much more in the STZ-treated group than that in the euglycemic group. Hyperglycemic mice contain a higher plasma H2O2-level than that from euglycemic mice. The injection of polyethylene glycol-conjugated catalase (PEG-CAT), an H2O2scavenger, may reverse hyperglycemia-induced tumor metastasis. In addition, hyperglycemia could also modulate the expression of epithelial-mesenchymal transition- (EMT-) related factors in pancreatic tumor tissues, as the E-cadherin level is decreased and the expression of mesenchymal markers N-cadherin and vimentin as well as transcription factor snail is strongly increased. The injection of PEG-CAT could also reverse hyperglycemia-induced EMT. These results suggest that the association between hyperglycemia and poor prognosis of pancreatic cancer can be attributed to the alterations of EMT through the production of hydrogen peroxide.

2014 ◽  
Vol 21 (1) ◽  
pp. 113-125 ◽  
Author(s):  
Sayantani Sarkar ◽  
Chandan Mandal ◽  
Rajender Sangwan ◽  
Chitra Mandal

β-catenin plays a pivotal role in organogenesis and oncogenesis. Alterations in β-catenin expression are common in pancreatic cancer, which is an extremely aggressive malignancy with a notably poor prognosis. In this report, we analyzed the apoptotic activity of withanolide-D (witha-D), a steroidal lactone that was purified from an Indian medicinal plant,Withania somnifera, and its underlying mechanism of action. Witha-D induced apoptosis in pancreatic ductal adenocarcinoma cells by prompting cell-cycle arrest at the G2/M phase. This lactone abrogated β-catenin signaling in these cells regardless of disease grade, mutational status, and gemcitabine sensitivity. Witha-D also upregulated E-cadherin in most cells, thereby supporting the inversion of the epithelial–mesenchymal transition. Furthermore, the Akt/Gsk3β kinase cascade was identified as a critical mediator of G2/M regulation and β-catenin signaling. Witha-D deactivated Akt, which failed to promote Gsk3β deactivation phosphorylation. Consequently, activated Gsk3β facilitated β-catenin destruction in pancreatic carcinoma cells. The knockdown of Chk1 and Chk2 further activated Akt and reversed the molecular signal. Taken together, the results of the current study represent the first evidence of β-catenin signal crosstalk during the G2/M phase by functionally inactivating Akt via witha-D treatment in pancreatic cancer cells. In conclusion, this finding suggests the potential identification of a new lead molecule in the treatment of pancreatic adenocarcinoma.


2021 ◽  
Author(s):  
ZHU ZENG ◽  
Shengbo Han ◽  
Yang Wang ◽  
Yan Huang ◽  
Yuhang Hu ◽  
...  

Abstract Background: Nutrient deprivation is a distinct feature of the tumor microenvironment that plays a crucial role in various cancers. However, the contribution and regulatory mechanism of nutrient deprivation on metastasis of pancreatic cancer (PC) have not been identified. Methods: PC cells were treated with normal medium, glucose-depletion or glutamine-depletion medium to observe the epithelial-mesenchymal transition (EMT). RT-qPCR and western blot assay were applied to evaluate the alteration of mRNA and protein of zinc finger E-box binding homeobox 1 (ZEB1), a crucial EMT regulator factor. Co-IP assay was utilized for evaluating the interaction between AMP-activated protein kinase (AMPK) and ZEB1. LncRNA microarray was adopted to detect the potential lncRNA, which facilitates the association between AMPK and ZEB1. Gain- and loss-of-function experiments were performed to evaluate the roles of ZNFX1 antisense RNA 1 (ZFAS1) in EMT and metastasis of PC. Results: The present study reveals that nutrient deprivation including glucose and glutamine deprivation significantly induces EMT of PC cells, which is dependent on stabilization of ZEB1. We further discover that nutrient deprivation induces upregulation of lncRNA ZFAS1, which promotes the association between AMPK and ZEB1 to phosphorylate and stabilize ZEB1 protein. Notably, ZEB1 reciprocally promotes the transcription of ZFAS1 by binding to the promoter of ZFAS1, forming feedback with ZFAS1. Consistently, depletion of ZFAS1 obviously inhibits nutrient deprivation-induced EMT of PC cells and lung metastasis of PC in nude mice. Meanwhile, clinical data displays that ZFAS1 is overexpressed in PC tissues and correlated with high expression of ZEB1 and Vimentin (VIM), low expression of E-cadherin (E-cad), as well as poor prognosis in PC patients. Conclusions: Our study implicates that glucose and glutamine deprivation promotes EMT and metastasis of PC through lncRNA-mediated stabilization of ZEB1.


2015 ◽  
Vol 13 (1) ◽  
pp. 237-242 ◽  
Author(s):  
YANLI YUAN ◽  
DEYU LI ◽  
HAIBO LI ◽  
LIANCAI WANG ◽  
GUANGJIN TIAN ◽  
...  

2011 ◽  
Vol 286 (12) ◽  
pp. 10495-10504 ◽  
Author(s):  
Mario A. Shields ◽  
Surabhi Dangi-Garimella ◽  
Seth B. Krantz ◽  
David J. Bentrem ◽  
Hidayatullah G. Munshi

Pancreatic ductal adenocarcinoma (PDAC) is characterized by pronounced fibrotic reaction composed primarily of type I collagen. Although type I collagen functions as a barrier to invasion, pancreatic cancer cells have been shown to respond to type I collagen by becoming more motile and invasive. Because epithelial-mesenchymal transition is also associated with cancer invasion, we examined the extent to which collagen modulated the expression of Snail, a well known regulator of epithelial-mesenchymal transition. Relative to cells grown on tissue culture plastic, PDAC cells grown in three-dimensional collagen gels induced Snail. Inhibiting the activity or expression of the TGF-β type I receptor abrogated collagen-induced Snail. Downstream of the receptor, we showed that Smad3 and Smad4 were critical for the induction of Snail by collagen. In contrast, Smad2 or ERK1/2 was not involved in collagen-mediated Snail expression. Overexpression of Snail in PDAC cells resulted in a robust membrane type 1-matrix metalloproteinase (MT1-MMP, MMP-14)-dependent invasion through collagen-coated transwell chambers. Snail-expressing PDAC cells also demonstrated MT1-MMP-dependent scattering in three-dimensional collagen gels. Mechanistically, Snail increased the expression of MT1-MMP through activation of ERK-MAPK signaling, and inhibiting ERK signaling in Snail-expressing cells blocked two-dimensional collagen invasion and attenuated scattering in three-dimensional collagen. To provide in vivo support for our findings that Snail can regulate MT1-MMP, we examined the expression of Snail and MT1-MMP in human PDAC tumors and found a statistically significant positive correlation between MT1-MMP and Snail in these tumors. Overall, our data demonstrate that pancreatic cancer cells increase Snail on encountering collagen-rich milieu and suggest that the desmoplastic reaction actively contributes to PDAC progression.


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