Acid-base transporters and pH dynamics in human breast carcinomas predict proliferative activity, metastasis, and survival
- Aarhus University, Denmark
- Regionshospitalet Randers, Denmark
- University of Southern Denmark, Denmark
Abstract
Breast cancer heterogeneity in histology and molecular subtype influences metabolic and proliferative activity and hence the acid load on cancer cells. We hypothesized that acid-base transporters and intracellular pH (pHi) dynamics contribute inter-individual variability in breast cancer aggressiveness and prognosis. We show that Na+,HCO3--cotransport and Na+/H+-exchange dominate cellular net acid extrusion in human breast carcinomas. Na+/H+-exchange elevates pHi preferentially in estrogen receptor-negative breast carcinomas, whereas Na+,HCO3--cotransport raises pHi more in invasive lobular than ductal breast carcinomas and in higher malignancy grade breast cancer. HER2-positive breast carcinomas have elevated protein expression of Na+/H+-exchanger NHE1/SLC9A1 and Na+,HCO3--cotransporter NBCn1/SLC4A7. Increased dependency on Na+,HCO3--cotransport associates with severe breast cancer: enlarged CO2/HCO3--dependent rises in pHi predict accelerated cell proliferation; whereas enhanced CO2/HCO3--dependent net acid extrusion, elevated NBCn1 protein expression, and reduced NHE1 protein expression predict lymph node metastasis. Accordingly, we observe reduced survival for patients suffering from Luminal A or Basal-like/triple-negative breast cancer with high SLC4A7 and/or low SLC9A1 mRNA expression. We conclude that the molecular mechanisms of acid-base regulation depend on clinicopathological characteristics of breast cancer patients. NBCn1 expression and dependency on Na+,HCO3--cotransport for pHi regulation, measured in biopsies of human primary breast carcinomas, independently predict proliferative activity, lymph node metastasis, and patient survival.
Data availability
- In order to comply with the ethical approval, we share the human data presented in Figure 1-8 and corresponding Figure Supplements (data on acid-base transport activity, intracellular pH, and protein expression of transporters linked to clinicopathological information) in de-identified form. Following consultation with the legal team at the Regional Committee on Health Research Ethics, we have generated dataset files where restricted information is grouped in intervals each consisting of no less than five individuals. To provide the reader with the best possible data insight, we also show Figure Supplements with more detailed and advanced plots of the data and include the corresponding de-identified dataset.- The meta analyses presented in Figure 9, 10, and corresponding figure supplements (data on RNA expression linked to patient survival) are based on data that have previously been published by other investigators (references 28-34), as detailed in the manuscript and the dataset list.
-
A gene-expression signature as a predictor of survival in breast cancerBudczies J, Kosztyla D (2020). cancerdata: Development and validation of diagnostic tests from high-dimensional molecular data: Datasets. R package version 1.28.0.; data(Vijver).
-
The molecular portraits of breast tumors are conserved across microarray platformsNCBI Gene Expression Omnibus, GSE1992.
-
Gene-expression profiles to predict distant metastasis of lymph-node-negative primary breast cancerNCBI Gene Expression Omnibus, GSE2034.
-
The humoral immune system has a key prognostic impact in node-negative breast cancerNCBI Gene Expression Omnibus, GSE11121.
-
Oncogenic pathway signatures in human cancers as a guide to targeted therapiesNCBI Gene Expression Omnibus, GSE3143.
Article and author information
Author details
Funding
Sundhed og Sygdom, Det Frie Forskningsråd (7025-00050B)
- Ebbe Boedtkjer
Novo Nordisk Fonden (NNF18OC0053037)
- Ebbe Boedtkjer
Danish Cancer Society (R136-A8670)
- Nicolai J Toft
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: All participants gave written informed consent. The Mid-Jutland regional division of the Danish Committee on Health Research Ethics (M-20100288) and the Danish Data Protection Agency (1-16-02-191-16) approved the procedures for tissue sampling and data handling, respectively.
Copyright
© 2021, Toft et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 1,747
- views
-
- 244
- downloads
-
- 25
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Acid-base transporters and pH dynamics in human breast carcinomas predict proliferative activity, metastasis, and survival
eLife 10:e68447.
https://doi.org/10.7554/eLife.68447
Further reading
-
- Cancer Biology
Most human pancreatic ductal adenocarcinoma (PDAC) are not infiltrated with cytotoxic T cells and are highly resistant to immunotherapy. Over 90% of PDAC have oncogenic KRAS mutations, and phosphoinositide 3-kinases (PI3Ks) are direct effectors of KRAS. Our previous study demonstrated that ablation of Pik3ca in KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cells induced host T cells to infiltrate and completely eliminate the tumors in a syngeneic orthotopic implantation mouse model. Now, we show that implantation of Pik3ca−/− KPC (named αKO) cancer cells induces clonal enrichment of cytotoxic T cells infiltrating the pancreatic tumors. To identify potential molecules that can regulate the activity of these anti-tumor T cells, we conducted an in vivo genome-wide gene-deletion screen using αKO cells implanted in the mouse pancreas. The result shows that deletion of propionyl-CoA carboxylase subunit B gene (Pccb) in αKO cells (named p-αKO) leads to immune evasion, tumor progression, and death of host mice. Surprisingly, p-αKO tumors are still infiltrated with clonally enriched CD8+ T cells but they are inactive against tumor cells. However, blockade of PD-L1/PD1 interaction reactivated these clonally enriched T cells infiltrating p-αKO tumors, leading to slower tumor progression and improve survival of host mice. These results indicate that Pccb can modulate the activity of cytotoxic T cells infiltrating some pancreatic cancers and this understanding may lead to improvement in immunotherapy for this difficult-to-treat cancer.
-
- Cancer Biology
- Immunology and Inflammation
In this study, we present a proof-of-concept classical vaccination experiment that validates the in silico identification of tumor neoantigens (TNAs) using a machine learning-based platform called NAP-CNB. Unlike other TNA predictors, NAP-CNB leverages RNA-seq data to consider the relative expression of neoantigens in tumors. Our experiments show the efficacy of NAP-CNB. Predicted TNAs elicited potent antitumor responses in mice following classical vaccination protocols. Notably, optimal antitumor activity was observed when targeting the antigen with higher expression in the tumor, which was not the most immunogenic. Additionally, the vaccination combining different neoantigens resulted in vastly improved responses compared to each one individually, showing the worth of multiantigen-based approaches. These findings validate NAP-CNB as an innovative TNA identification platform and make a substantial contribution to advancing the next generation of personalized immunotherapies.
