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The Crosstalk between Nrf2 and TGF-β1 in the Epithelial-Mesenchymal Transition of Pancreatic Duct Epithelial Cells.

Arfmann-Knübel S, Struck B, Genrich G, Helm O, Sipos B, Sebens S, Schäfer H - PLoS ONE (2015)

Bottom Line: In Colo357 cells, TGF-β1 itself was capable of inducing Nrf2 whereas in HPDE cells TGF-β1 per-se did not affect Nrf2 activity, but enhanced Nrf2 induction by tBHQ.In Colo357, but not in HPDE cells, the effects of TGF-β1 on invasion were sensitive to Nrf2 knock-down.In both cell lines, E-cadherin re-expression inhibited the proinvasive effect of Nrf2.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Gastroenterology, Dept. of Internal Medicine I, UKSH Campus Kiel, Arnold-Heller-Str. 3, Bldg. 6, 24105, Kiel, Germany.

ABSTRACT
Nrf2 and TGF-β1 both affect tumorigenesis in a dual fashion, either by preventing carcinogen induced carcinogenesis and suppressing tumor growth, respectively, or by conferring cytoprotection and invasiveness to tumor cells during malignant transformation. Given the involvement of Nrf2 and TGF-β1 in the adaptation of epithelial cells to persistent inflammatory stress, e.g. of the pancreatic duct epithelium during chronic pancreatitis, a crosstalk between Nrf2 and TGF-β1 can be envisaged. By using premalignant human pancreatic duct cells (HPDE) and the pancreatic ductal adenocarcinoma cell line Colo357, we could show that Nrf2 and TGF-β1 independently but additively conferred an invasive phenotype to HPDE cells, whereas acting synergistically in Colo357 cells. This was accompanied by differential regulation of EMT markers like vimentin, Slug, L1CAM and E-cadherin. Nrf2 activation suppressed E-cadherin expression through an as yet unidentified ARE related site in the E-cadherin promoter, attenuated TGF-β1 induced Smad2/3-activity and enhanced JNK-signaling. In Colo357 cells, TGF-β1 itself was capable of inducing Nrf2 whereas in HPDE cells TGF-β1 per-se did not affect Nrf2 activity, but enhanced Nrf2 induction by tBHQ. In Colo357, but not in HPDE cells, the effects of TGF-β1 on invasion were sensitive to Nrf2 knock-down. In both cell lines, E-cadherin re-expression inhibited the proinvasive effect of Nrf2. Thus, the increased invasion of both cell lines relates to the Nrf2-dependent downregulation of E-cadherin expression. In line, immunohistochemistry analysis of human pancreatic intraepithelial neoplasias in pancreatic tissues from chronic pancreatitis patients revealed strong Nrf2 activity already in premalignant epithelial duct cells, accompanied by partial loss of E-cadherin expression. Our findings indicate that Nrf2 and TGF-β1 both contribute to malignant transformation through distinct EMT related mechanisms accounting for an invasive phenotype. Provided a crosstalk between both pathways, Nrf2 and TGF-β1 mutually promote their tumorigenic potential, a condition manifesting already at an early stage during inflammation induced carcinogenesis of the pancreas.

No MeSH data available.


Related in: MedlinePlus

Immunohistochemistry analysis for activated Nrf2 and E-cadherin expression in premalignant pancreatic tissues.Formalin fixed and paraffin embedded pancreatic tissues from CP patients was subjected to immunostaining for P-Nrf2 and E-cadherin. Representative images are shown of (A) normal ducts and PanIN lesions exhibiting high expression of P-Nrf2 or (B) PanIN lesions with low expression of P-Nrf2 that display the respective reciprocal expression level of E-cadherin. Usage of the isotype matched control antibodies revealed no or only weak background staining (not shown). Images were taken at 400x magnification. Arrows indicate ductal regions of reciprocal P-Nrf2 and E-cadherin expression within the same lesion.
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pone.0132978.g009: Immunohistochemistry analysis for activated Nrf2 and E-cadherin expression in premalignant pancreatic tissues.Formalin fixed and paraffin embedded pancreatic tissues from CP patients was subjected to immunostaining for P-Nrf2 and E-cadherin. Representative images are shown of (A) normal ducts and PanIN lesions exhibiting high expression of P-Nrf2 or (B) PanIN lesions with low expression of P-Nrf2 that display the respective reciprocal expression level of E-cadherin. Usage of the isotype matched control antibodies revealed no or only weak background staining (not shown). Images were taken at 400x magnification. Arrows indicate ductal regions of reciprocal P-Nrf2 and E-cadherin expression within the same lesion.

Mentions: Hereby it was shown that nuclear P-Nrf2 levels were significantly elevated already in the epithelium of PanIN lesions when compared to healthy ducts (Fig 9A). Overall 36 PanIN structures found in 11/20 CP patients were analysed, 23 of which (64%) exhibited considerable P-Nrf2 staining (score >1). E-cadherin expression in these 23 lesions was still high (score >1) only in 9 cases and diminished (score <1) in 14 cases. In those 6 ductal PanIN structures with greatest expression level of nuclear P-Nrf2 (score = 2), E-cadherin expression was almost lost (score = 0). In turn, the 13 PanIN lesions with marginal or undetectable P-Nrf2 activity (score <1) exhibited high (score >1) and low (score <1) E-cadherin expression in 10 and 3 cases, respectively (Fig 9B).


The Crosstalk between Nrf2 and TGF-β1 in the Epithelial-Mesenchymal Transition of Pancreatic Duct Epithelial Cells.

Arfmann-Knübel S, Struck B, Genrich G, Helm O, Sipos B, Sebens S, Schäfer H - PLoS ONE (2015)

Immunohistochemistry analysis for activated Nrf2 and E-cadherin expression in premalignant pancreatic tissues.Formalin fixed and paraffin embedded pancreatic tissues from CP patients was subjected to immunostaining for P-Nrf2 and E-cadherin. Representative images are shown of (A) normal ducts and PanIN lesions exhibiting high expression of P-Nrf2 or (B) PanIN lesions with low expression of P-Nrf2 that display the respective reciprocal expression level of E-cadherin. Usage of the isotype matched control antibodies revealed no or only weak background staining (not shown). Images were taken at 400x magnification. Arrows indicate ductal regions of reciprocal P-Nrf2 and E-cadherin expression within the same lesion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520686&req=5

pone.0132978.g009: Immunohistochemistry analysis for activated Nrf2 and E-cadherin expression in premalignant pancreatic tissues.Formalin fixed and paraffin embedded pancreatic tissues from CP patients was subjected to immunostaining for P-Nrf2 and E-cadherin. Representative images are shown of (A) normal ducts and PanIN lesions exhibiting high expression of P-Nrf2 or (B) PanIN lesions with low expression of P-Nrf2 that display the respective reciprocal expression level of E-cadherin. Usage of the isotype matched control antibodies revealed no or only weak background staining (not shown). Images were taken at 400x magnification. Arrows indicate ductal regions of reciprocal P-Nrf2 and E-cadherin expression within the same lesion.
Mentions: Hereby it was shown that nuclear P-Nrf2 levels were significantly elevated already in the epithelium of PanIN lesions when compared to healthy ducts (Fig 9A). Overall 36 PanIN structures found in 11/20 CP patients were analysed, 23 of which (64%) exhibited considerable P-Nrf2 staining (score >1). E-cadherin expression in these 23 lesions was still high (score >1) only in 9 cases and diminished (score <1) in 14 cases. In those 6 ductal PanIN structures with greatest expression level of nuclear P-Nrf2 (score = 2), E-cadherin expression was almost lost (score = 0). In turn, the 13 PanIN lesions with marginal or undetectable P-Nrf2 activity (score <1) exhibited high (score >1) and low (score <1) E-cadherin expression in 10 and 3 cases, respectively (Fig 9B).

Bottom Line: In Colo357 cells, TGF-β1 itself was capable of inducing Nrf2 whereas in HPDE cells TGF-β1 per-se did not affect Nrf2 activity, but enhanced Nrf2 induction by tBHQ.In Colo357, but not in HPDE cells, the effects of TGF-β1 on invasion were sensitive to Nrf2 knock-down.In both cell lines, E-cadherin re-expression inhibited the proinvasive effect of Nrf2.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Gastroenterology, Dept. of Internal Medicine I, UKSH Campus Kiel, Arnold-Heller-Str. 3, Bldg. 6, 24105, Kiel, Germany.

ABSTRACT
Nrf2 and TGF-β1 both affect tumorigenesis in a dual fashion, either by preventing carcinogen induced carcinogenesis and suppressing tumor growth, respectively, or by conferring cytoprotection and invasiveness to tumor cells during malignant transformation. Given the involvement of Nrf2 and TGF-β1 in the adaptation of epithelial cells to persistent inflammatory stress, e.g. of the pancreatic duct epithelium during chronic pancreatitis, a crosstalk between Nrf2 and TGF-β1 can be envisaged. By using premalignant human pancreatic duct cells (HPDE) and the pancreatic ductal adenocarcinoma cell line Colo357, we could show that Nrf2 and TGF-β1 independently but additively conferred an invasive phenotype to HPDE cells, whereas acting synergistically in Colo357 cells. This was accompanied by differential regulation of EMT markers like vimentin, Slug, L1CAM and E-cadherin. Nrf2 activation suppressed E-cadherin expression through an as yet unidentified ARE related site in the E-cadherin promoter, attenuated TGF-β1 induced Smad2/3-activity and enhanced JNK-signaling. In Colo357 cells, TGF-β1 itself was capable of inducing Nrf2 whereas in HPDE cells TGF-β1 per-se did not affect Nrf2 activity, but enhanced Nrf2 induction by tBHQ. In Colo357, but not in HPDE cells, the effects of TGF-β1 on invasion were sensitive to Nrf2 knock-down. In both cell lines, E-cadherin re-expression inhibited the proinvasive effect of Nrf2. Thus, the increased invasion of both cell lines relates to the Nrf2-dependent downregulation of E-cadherin expression. In line, immunohistochemistry analysis of human pancreatic intraepithelial neoplasias in pancreatic tissues from chronic pancreatitis patients revealed strong Nrf2 activity already in premalignant epithelial duct cells, accompanied by partial loss of E-cadherin expression. Our findings indicate that Nrf2 and TGF-β1 both contribute to malignant transformation through distinct EMT related mechanisms accounting for an invasive phenotype. Provided a crosstalk between both pathways, Nrf2 and TGF-β1 mutually promote their tumorigenic potential, a condition manifesting already at an early stage during inflammation induced carcinogenesis of the pancreas.

No MeSH data available.


Related in: MedlinePlus