Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue

The acidic tumor microenvironment modifies malignant cell behavior. Here, we study consequences of the microenvironment in breast carcinomas. Beginning at carcinogen-based breast cancer induction, we supply either regular or NaHCO<sub>3</sub>-containing drinking water to female C57BL/6j...

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Main Authors: Ninna C. S. Voss, Thomas Dreyer, Mikkel B. Henningsen, Pernille Vahl, Bent Honoré, Ebbe Boedtkjer
Format: Article
Language:English
Published: MDPI AG 2020-04-01
Series:Cancers
Subjects:
Online Access:https://www.mdpi.com/2072-6694/12/4/891
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author Ninna C. S. Voss
Thomas Dreyer
Mikkel B. Henningsen
Pernille Vahl
Bent Honoré
Ebbe Boedtkjer
author_facet Ninna C. S. Voss
Thomas Dreyer
Mikkel B. Henningsen
Pernille Vahl
Bent Honoré
Ebbe Boedtkjer
author_sort Ninna C. S. Voss
collection DOAJ
description The acidic tumor microenvironment modifies malignant cell behavior. Here, we study consequences of the microenvironment in breast carcinomas. Beginning at carcinogen-based breast cancer induction, we supply either regular or NaHCO<sub>3</sub>-containing drinking water to female C57BL/6j mice. We evaluate urine and blood acid-base status, tumor metabolism (microdialysis sampling), and tumor pH (pH-sensitive microelectrodes) in vivo. Based on freshly isolated epithelial organoids from breast carcinomas and normal breast tissue, we assess protein expression (immunoblotting, mass spectrometry), intracellular pH (fluorescence microscopy), and cell proliferation (bromodeoxyuridine incorporation). Oral NaHCO<sub>3</sub> therapy increases breast tumor pH in vivo from 6.68 ± 0.04 to 7.04 ± 0.09 and intracellular pH in breast epithelial organoids by ~0.15. Breast tumors develop with median latency of 85.5 ± 8.2 days in NaHCO<sub>3</sub>-treated mice vs. 82 ± 7.5 days in control mice. Oral NaHCO<sub>3</sub> therapy does not affect tumor growth, histopathology or glycolytic metabolism. The capacity for cellular net acid extrusion is increased in NaHCO<sub>3</sub>-treated mice and correlates negatively with breast tumor latency. Oral NaHCO<sub>3</sub> therapy elevates proliferative activity in organoids from breast carcinomas. Changes in protein expression patterns—observed by high-throughput proteomics analyses—between cancer and normal breast tissue and in response to oral NaHCO<sub>3</sub> therapy reveal complex influences on metabolism, cytoskeleton, cell-cell and cell-matrix interaction, and cell signaling pathways. We conclude that oral NaHCO<sub>3</sub> therapy neutralizes the microenvironment of breast carcinomas, elevates the cellular net acid extrusion capacity, and accelerates proliferation without net effect on breast cancer development or tumor growth. We demonstrate unexpected pro-neoplastic consequences of oral NaHCO<sub>3</sub> therapy that in breast tissue cancel out previously reported anti-neoplastic effects.
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spelling doaj.art-b609ea6c849a44b9b027b0284705d2472023-11-19T20:51:13ZengMDPI AGCancers2072-66942020-04-0112489110.3390/cancers12040891Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast TissueNinna C. S. Voss0Thomas Dreyer1Mikkel B. Henningsen2Pernille Vahl3Bent Honoré4Ebbe Boedtkjer5Department of Biomedicine, Aarhus University, DK-8000 Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, DK-8000 Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, DK-8000 Aarhus, DenmarkDepartment of Pathology, Aarhus University Hospital, DK-8200 Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, DK-8000 Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, DK-8000 Aarhus, DenmarkThe acidic tumor microenvironment modifies malignant cell behavior. Here, we study consequences of the microenvironment in breast carcinomas. Beginning at carcinogen-based breast cancer induction, we supply either regular or NaHCO<sub>3</sub>-containing drinking water to female C57BL/6j mice. We evaluate urine and blood acid-base status, tumor metabolism (microdialysis sampling), and tumor pH (pH-sensitive microelectrodes) in vivo. Based on freshly isolated epithelial organoids from breast carcinomas and normal breast tissue, we assess protein expression (immunoblotting, mass spectrometry), intracellular pH (fluorescence microscopy), and cell proliferation (bromodeoxyuridine incorporation). Oral NaHCO<sub>3</sub> therapy increases breast tumor pH in vivo from 6.68 ± 0.04 to 7.04 ± 0.09 and intracellular pH in breast epithelial organoids by ~0.15. Breast tumors develop with median latency of 85.5 ± 8.2 days in NaHCO<sub>3</sub>-treated mice vs. 82 ± 7.5 days in control mice. Oral NaHCO<sub>3</sub> therapy does not affect tumor growth, histopathology or glycolytic metabolism. The capacity for cellular net acid extrusion is increased in NaHCO<sub>3</sub>-treated mice and correlates negatively with breast tumor latency. Oral NaHCO<sub>3</sub> therapy elevates proliferative activity in organoids from breast carcinomas. Changes in protein expression patterns—observed by high-throughput proteomics analyses—between cancer and normal breast tissue and in response to oral NaHCO<sub>3</sub> therapy reveal complex influences on metabolism, cytoskeleton, cell-cell and cell-matrix interaction, and cell signaling pathways. We conclude that oral NaHCO<sub>3</sub> therapy neutralizes the microenvironment of breast carcinomas, elevates the cellular net acid extrusion capacity, and accelerates proliferation without net effect on breast cancer development or tumor growth. We demonstrate unexpected pro-neoplastic consequences of oral NaHCO<sub>3</sub> therapy that in breast tissue cancel out previously reported anti-neoplastic effects.https://www.mdpi.com/2072-6694/12/4/891acidosisbuffer therapybicarbonatemass spectrometrypHproteomics
spellingShingle Ninna C. S. Voss
Thomas Dreyer
Mikkel B. Henningsen
Pernille Vahl
Bent Honoré
Ebbe Boedtkjer
Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue
Cancers
acidosis
buffer therapy
bicarbonate
mass spectrometry
pH
proteomics
title Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue
title_full Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue
title_fullStr Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue
title_full_unstemmed Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue
title_short Targeting the Acidic Tumor Microenvironment: Unexpected Pro-Neoplastic Effects of Oral NaHCO<sub>3</sub> Therapy in Murine Breast Tissue
title_sort targeting the acidic tumor microenvironment unexpected pro neoplastic effects of oral nahco sub 3 sub therapy in murine breast tissue
topic acidosis
buffer therapy
bicarbonate
mass spectrometry
pH
proteomics
url https://www.mdpi.com/2072-6694/12/4/891
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