TY - JOUR
T1 - Paracrine IL-6 signaling mediates the effects of pancreatic stellate cells on epithelial-mesenchymal transition via Stat3/Nrf2 pathway in pancreatic cancer cells
AU - Wu, Yuan Seng
AU - Chung, Ivy
AU - Wong, Won Fen
AU - Masamune, Atsushi
AU - Sim, Maw Shin
AU - Looi, Chung Yeng
N1 - Funding Information:
The authors thank Dr. Retnagowri Rajandram for her valuable assistance reviewing the manuscript. The authors also gratefully acknowledge the financial supports by University of Malaya RP027A-14HTM (Looi), Grant-in-Aid from the Japan Society for the Promotion of Science 15H04804 (Masamune), and Malaysia Ministry of Education MyBrain 15 fellowship KPT (B) 860221145079 (Wu).
PY - 2017/2/1
Y1 - 2017/2/1
N2 - Background We previously showed that pancreatic stellate cells (PSC) secreted interleukin (IL)-6 and promoted pancreatic ductal adenocarcinoma (PDAC) cell proliferation via nuclear factor erythroid 2 (Nrf2)-mediated metabolic reprogramming. Epithelial-mesenchymal transition (EMT) is a key process for the metastatic cascade. To study the mechanism of PDAC progression to metastasis, we investigated the role of PSC-secreted IL-6 in activating EMT and the involvement of Nrf2 in this process. Methods Gene expression of IL-6 and IL-6Rα in PSC and PDAC cells was measured with qRT-PCR. The role of PSC-secreted IL-6, JAK/Stat3 signaling, and Nrf2 mediation on EMT-related genes expression was also examined with qRT-PCR. EMT phenotypes were assessed with morphological change, wound healing, migration, and invasion. Results PSC expressed higher mRNA levels of IL-6 but lower IL-6Rα compared to PDAC cells. Neutralizing IL-6 in PSC secretion reduced mesenchymal-like morphology, migration and invasion capacity, and mesenchymal-like gene expression of N-cadherin, vimentin, fibronectin, collagen I, Sip1, Snail, Slug, and Twist2. Inhibition of JAK/Stat3 signaling induced by IL-6 repressed EMT and Nrf2 gene expression. Induction of Nrf2 activity by tert-butylhydroquinone (tBHQ) increased both EMT phenotypes and gene expression (N-cadherin, fibronectin, Twist2, Snail, and Slug) repressed by IL-6 neutralizing antibody. Simultaneous inhibition of Nrf2 expression with siRNA and Stat3 signaling further repressed EMT gene expression, indicating that Stat3/Nrf2 pathway mediates EMT induced by IL-6. Conclusions IL-6 from PSC promotes EMT in PDAC cells via Stat3/Nrf2 pathway. General significance Targeting Stat3/Nrf2 pathway activated by PSC-secreted IL-6 may provide a novel therapeutic option to improve the prognosis of PDAC.
AB - Background We previously showed that pancreatic stellate cells (PSC) secreted interleukin (IL)-6 and promoted pancreatic ductal adenocarcinoma (PDAC) cell proliferation via nuclear factor erythroid 2 (Nrf2)-mediated metabolic reprogramming. Epithelial-mesenchymal transition (EMT) is a key process for the metastatic cascade. To study the mechanism of PDAC progression to metastasis, we investigated the role of PSC-secreted IL-6 in activating EMT and the involvement of Nrf2 in this process. Methods Gene expression of IL-6 and IL-6Rα in PSC and PDAC cells was measured with qRT-PCR. The role of PSC-secreted IL-6, JAK/Stat3 signaling, and Nrf2 mediation on EMT-related genes expression was also examined with qRT-PCR. EMT phenotypes were assessed with morphological change, wound healing, migration, and invasion. Results PSC expressed higher mRNA levels of IL-6 but lower IL-6Rα compared to PDAC cells. Neutralizing IL-6 in PSC secretion reduced mesenchymal-like morphology, migration and invasion capacity, and mesenchymal-like gene expression of N-cadherin, vimentin, fibronectin, collagen I, Sip1, Snail, Slug, and Twist2. Inhibition of JAK/Stat3 signaling induced by IL-6 repressed EMT and Nrf2 gene expression. Induction of Nrf2 activity by tert-butylhydroquinone (tBHQ) increased both EMT phenotypes and gene expression (N-cadherin, fibronectin, Twist2, Snail, and Slug) repressed by IL-6 neutralizing antibody. Simultaneous inhibition of Nrf2 expression with siRNA and Stat3 signaling further repressed EMT gene expression, indicating that Stat3/Nrf2 pathway mediates EMT induced by IL-6. Conclusions IL-6 from PSC promotes EMT in PDAC cells via Stat3/Nrf2 pathway. General significance Targeting Stat3/Nrf2 pathway activated by PSC-secreted IL-6 may provide a novel therapeutic option to improve the prognosis of PDAC.
KW - Cancer-associated fibroblasts
KW - Cytokines
KW - Mechanism
KW - Metastasis
KW - Pancreatic ductal adenocarcinoma
KW - Tumor microenvironment
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U2 - 10.1016/j.bbagen.2016.10.006
DO - 10.1016/j.bbagen.2016.10.006
M3 - Article
C2 - 27750041
AN - SCOPUS:85002152597
VL - 1861
SP - 296
EP - 306
JO - Biochimica et Biophysica Acta - General Subjects
JF - Biochimica et Biophysica Acta - General Subjects
SN - 0006-3002
IS - 2
ER -