ABSTRACT: To investigate the function of nuclear factor (NF)-κB in the epithelial to mesenchymal transition induced by hypoxia in pancreatic cancer cells.
For cultured pancreatic cancer cells (BxPC-3 and Panc-1) under hypoxic and normoxic conditions, the differences in the morphology were observed by optical microscope. The expression of markers of epithelial and mesenchymal phenotypes, E-cadherin, vimentin and N-cadherin, were determined by Western blot. NF-κB P65 activity was measured by electrophoretic mobility shift assay. Invasion and gemcitabine resistance of pancreatic cancer cells were evaluated in matrigel invasion assay and cell counting kit-8 assay. Both molecular and pharmacologic means of inhibiting NF-κB P65 were used in these hypoxic cells and then the above resulting phenotypes were compared with those of the control-treated cells.
After cultured pancreatic cancer cells under hypoxic conditions for 48 h, normoxic cells exhibited a polygonal shape and formed tight clusters of cells, whereas hypoxic cells took on an elongated, fibroblastoid morphology associated with a more highly invasive character and resistance to gemcitabine; hypoxic cells exhibited an suppression of E-cadherin and increase in vimentin and N-cadherin expression. NF-κB P65 activity was elevated in hypoxic cells. On the contrary, on molecular or pharmacologic inhibition of NF-κB P65, hypoxic cells regained expression of E-cadherin, lost expression of N-cadherin, and reversed their highly invasive and drug resistant phenotype.
Pancreatic cancer cells underwent epithelial to mesenchymal transition exposed to hypoxia, exhibited highly invasive and drug resistant phenotype. Inhibition of NF-κB P65 under hypoxic conditions, pancreatic cancer cells regained expression of E-cadherin, lost expression of N-cadherin, and reversed their highly invasive and drug resistant phenotype.
Zhonghua wai ke za zhi [Chinese journal of surgery] 05/2012; 50(5):446-51.
ABSTRACT: Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, has recently shown antitumor activity in various cancer cells. Apo2 ligand or tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) is regarded as a promising anticancer agent, but chemoresistance affects its efficacy as a treatment strategy. Apoptosis induced by the combination of DHA and Apo2L/TRAIL has not been well documented, and the mechanisms involved remain unclear.
Here, we report that DHA enhances the efficacy of Apo2L/TRAIL for the treatment of pancreatic cancer. We found that combined therapy using DHA and Apo2L/TRAIL significantly enhanced apoptosis in BxPC-3 and PANC-1 cells compared with single-agent treatment in vitro. The effect of DHA was mediated through the generation of reactive oxygen species, the induction of death receptor 5 (DR5) and the modulation of apoptosis-related proteins. However, N-acetyl cysteine significantly reduced the enhanced apoptosis observed with the combination of DHA and Apo2L/TRAIL. In addition, knockdown of DR5 by small interfering RNA also significantly reduced the amount of apoptosis induced by DHA and Apo2L/TRAIL.
These results suggest that DHA enhances Apo2L/TRAIL-mediated apoptosis in human pancreatic cancer cells through reactive oxygen species-mediated up-regulation of DR5.
PLoS ONE 01/2012; 7(5):e37222. · 4.09 Impact Factor
ABSTRACT: Epithelial to mesenchymal transition (EMT) induced by hypoxia is one of the critical causes of treatment failure in different types of human cancers. NF-κB is closely involved in the progression of EMT. Compared with HIF-1α, the correlation between NF-κB and EMT during hypoxia has been less studied, and although the phenomenon was observed in the past, the molecular mechanisms involved remained unclear.
Here, we report that hypoxia or overexpression of hypoxia-inducible factor-1α (HIF-1α) promotes EMT in pancreatic cancer cells. On molecular or pharmacologic inhibition of NF-κB, hypoxic cells regained expression of E-cadherin, lost expression of N-cadherin, and attenuated their highly invasive and drug-resistant phenotype. Introducing a pcDNA3.0/HIF-1α into pancreatic cancer cells under normoxic conditions heightened NF-κB activity, phenocopying EMT effects produced by hypoxia. Conversely, inhibiting the heightened NF-κB activity in this setting attenuated the EMT phenotype.
These results suggest that hypoxia or overexpression of HIF-1α induces the EMT that is largely dependent on NF-κB in pancreatic cancer cells.
PLoS ONE 01/2011; 6(8):e23752. · 4.09 Impact Factor