Acid-base homeostasis orchestrated by NHE1 defines the pancreatic stellate cell phenotype in pancreatic cancer
Zoltán Pethő, Karolina Najder, Stephanie Beel, Benedikt Fels, Ilka Neumann, Sandra Schimmelpfennig, Sarah Sargin, Maria Wolters, Klavs Grantins, Eva Wardelmann, Miso Mitkovski, Andrea Oeckinghaus, Albrecht Schwab
Zoltán Pethő, Karolina Najder, Stephanie Beel, Benedikt Fels, Ilka Neumann, Sandra Schimmelpfennig, Sarah Sargin, Maria Wolters, Klavs Grantins, Eva Wardelmann, Miso Mitkovski, Andrea Oeckinghaus, Albrecht Schwab
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Research Article Metabolism Oncology

Acid-base homeostasis orchestrated by NHE1 defines the pancreatic stellate cell phenotype in pancreatic cancer

Abstract

Pancreatic ductal adenocarcinoma (PDAC) progresses in an organ with a unique pH landscape, where the stroma acidifies after each meal. We hypothesized that disrupting this pH landscape during PDAC progression triggers pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs) to induce PDAC fibrosis. We revealed that alkaline environmental pH was sufficient to induce PSC differentiation to a myofibroblastic phenotype. We then mechanistically dissected this finding, focusing on the involvement of the Na+/H+ exchanger NHE1. Perturbing cellular pH homeostasis by inhibiting NHE1 with cariporide partially altered the myofibroblastic PSC phenotype. To show the relevance of this finding in vivo, we targeted NHE1 in murine PDAC (KPfC). Indeed, tumor fibrosis decreased when mice received the NHE1-inhibitor cariporide in addition to gemcitabine treatment. Moreover, the tumor immune infiltrate shifted from granulocyte rich to more lymphocytic. Taken together, our study provides mechanistic evidence on how the pancreatic pH landscape shapes pancreatic cancer through tuning PSC differentiation.

Authors

Zoltán Pethő, Karolina Najder, Stephanie Beel, Benedikt Fels, Ilka Neumann, Sandra Schimmelpfennig, Sarah Sargin, Maria Wolters, Klavs Grantins, Eva Wardelmann, Miso Mitkovski, Andrea Oeckinghaus, Albrecht Schwab

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Figure 6

NHE1 orchestrates PDAC-derived CAF activation.

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NHE1 orchestrates PDAC-derived CAF activation. (A) Representative H&...
(A) Representative H&E and IHC images of healthy and tumorous ducts. The colors of the IHC image indicate cell nuclei stained with NHE1 (magenta), αSMA+ PSCs and CAFs (yellow), DAPI (cyan), and CK19+ ductal or tumor cells (green). Scale bar: 40 μm. (B) αSMA+ cells (*) from A are depicted with higher magnification, which are also NHE1+. Scale bar: 20 μm (C) Immunocytochemistry of CAFs derived from KPfC mice after a 1-month treatment with vehicle (top) or gemcitabine + cariporide (bottom). Myofibroblast marker αSMA (yellow), the general mesenchymal marker vimentin (magenta), and nuclei (cyan) are labeled. Scale bar: 20 μm. (D) KPfC-derived CAF activation after therapy was assessed by multiplying cell area with the fluorescence intensity of αSMA. nVehicle = 61, nGEM = 59, nCARI = 63, nGEM+CARI = 70 from N ≥ 3 mice. Note the logarithmic scale of the ordinate. (E) Trajectories of migrating KPfC-derived CAFs are shown by individual black lines. The treatment of the respective mice is indicated. Trajectories of the treatment groups are always normalized to common starting points. The radii of the orange circles highlight the mean translocation of cells in each population. Scale bar: 20 μm. (F) Mean cell migration velocities of individual CAFs were calculated from the trajectories in C. nVehicle = 30, nGEM = 30, nCARI = 19, nGEM+CARI = 40 cells from N ≥ 3 mice. Statistical tests in D and F were performed with 1-way ANOVA with Tukey’s post hoc test.