The microenvironment within tumors is significantly different from normal tissue. The chaotic vasculature leads to transient or chronic hypoxia which leads to acidification of the interstitial space. This creates a cytotoxic environment for normal cells while favoring tumor growth through degradation of extracellular matrix, induction of angiogenic factors, enhanced migration, and immunologic evasion. Our application focuses on the mechanisms that regulate acidification. We have assembled a group of outstanding investigators and will use state-of-the-art approaches to provide new insights in control of the tumor microenvironment in breast cancer. Our overall goal is to understand the role of membrane-bound carbonic anhydrases, whose catalytic domains face the extracellular milieu, in controlling acidification in breast cancer. Specifically, we will test the hypothesis that membrane bound carbonic anhydrase is mechanistically responsible for regulating pH in the tumor microenvironment. Increased carbonic anhydrase IX (CAIX) expression in primary breast cancers is a marker for hypoxia, an indicator of poor prognosis, and associated with high-grade estrogen receptor negative tumors. For unknown reasons, carbonic anhydrase XII (CAXII) expression in breast cancer is an indicator of good prognosis. Few investigators have studied CAIX or CAXII in the native breast cancer environment, as we propose, which will provide the most accurate appraisal of their roles in pH control. We have developed the methodology to compare the kinetics of these two proteins to determine if differences in their intrinsic activity r environment underlie this paradox. We challenge the current paradigm that CAIX contributes solely to the development of the acidic tumor microenvironment. Rather, our data suggest that CAIX has the ability to balance tumor extracellular pH by improving extracellular buffering using the CO2/bicarbonate system. In contrast, CAXII is a better enzyme at higher pH.
The aims of our proposal are: 1.) To compare the kinetics of CAIX and CAXII in basal B and luminal breast cancer cells. 2.) To analyze the mechanism(s) by which breast cancer cells control extracellular pH. 3.) To assess the role of CA on pH control in xenograft breast cancer tumors comprised of breast cancer cells and human tissue grafts. These data will be particularly important for those women who have triple negative breast cancers. These cancers are strongly associated with CAIX expression, predominate in the minority populations, and have no specific treatment modalities. We believe that our proposal has high impact as it uses innovative approaches, addresses unique hypotheses, may reveal new strategies for therapeutic intervention in breast cancer, has applicability to other cancer types, and has a great chance of success.

Public Health Relevance

We hypothesize that the activity of membrane-bound carbonic anhydrases are key players in modulating extracellular pH in the tumor microenvironment. Specifically, we propose that the activities of carbonic anhydrase IX (CAIX) and carbonic anhydrase XII (CAXII) differ within the context of the breast cancer environment may underlie the opposite prognosis for breast cancer patients whose tumors express one or the other CA. The impact of such studies may have far reaching consequences for treatment not only of breast cancer, but for other cancers that express exofacial CAs.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
3R01CA165284-04S1
Application #
9222248
Study Section
Tumor Progression and Metastasis Study Section (TPM)
Program Officer
Lin, Alison J
Project Start
2013-04-04
Project End
2018-03-31
Budget Start
2016-04-01
Budget End
2017-03-31
Support Year
4
Fiscal Year
2016
Total Cost
Indirect Cost
Name
University of Florida
Department
Biochemistry
Type
Schools of Medicine
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Mboge, Mam Y; Kota, Anusha; McKenna, Robert et al. (2018) Biophysical, Biochemical, and Cell Based Approaches Used to Decipher the Role of Carbonic Anhydrases in Cancer and to Evaluate the Potency of Targeted Inhibitors. Int J Med Chem 2018:2906519
Chen, Zhijuan; Ai, Lingbao; Mboge, Mam Y et al. (2018) UFH-001 cells: A novel triple negative, CAIX-positive, human breast cancer model system. Cancer Biol Ther 19:598-608
Mboge, Mam Y; Chen, Zhijuan; Wolff, Alyssa et al. (2018) Selective inhibition of carbonic anhydrase IX over carbonic anhydrase XII in breast cancer cells using benzene sulfonamides: Disconnect between activity and growth inhibition. PLoS One 13:e0207417
Singh, Srishti; Lomelino, Carrie L; Mboge, Mam Y et al. (2018) Cancer Drug Development of Carbonic Anhydrase Inhibitors beyond the Active Site. Molecules 23:
Mboge, Mam Y; Mahon, Brian P; McKenna, Robert et al. (2018) Carbonic Anhydrases: Role in pH Control and Cancer. Metabolites 8:
Mboge, Mam Y; Mahon, Brian P; Lamas, Nicole et al. (2017) Structure activity study of carbonic anhydrase IX: Selective inhibition with ureido-substituted benzenesulfonamides. Eur J Med Chem 132:184-191
Cadoni, Roberta; Pala, Nicolino; Lomelino, Carrie et al. (2017) Exploring Heteroaryl-pyrazole Carboxylic Acids as Human Carbonic Anhydrase XII Inhibitors. ACS Med Chem Lett 8:941-946
Mahon, Brian P; Bhatt, Avni; Socorro, Lilien et al. (2016) The Structure of Carbonic Anhydrase IX Is Adapted for Low-pH Catalysis. Biochemistry 55:4642-53
Mahon, Brian P; Hendon, Alex M; Driscoll, Jenna M et al. (2015) Saccharin: a lead compound for structure-based drug design of carbonic anhydrase IX inhibitors. Bioorg Med Chem 23:849-54
Mboge, Mam Y; McKenna, Robert; Frost, Susan C (2015) Advances in Anti-Cancer Drug Development Targeting Carbonic Anhydrase IX and XII. Top Anticancer Res 5:3-42

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