title: Lactoferrin selectively triggers apoptosis in highly metastatic breast cancer cells through inhibition of plasmalemmal V-H+-ATPase.
abstract: Breast cancer is the most common type of cancer affecting women. Despite the good prognosis when detected early, significant challenges remain in the treatment of metastatic breast cancer. The recruitment of the vacuolar H+-ATPase (V-H+-ATPase) to the plasma membrane, where it mediates the acidification of the tumor microenvironment (TME), is a recognized feature involved in the acquisition of a metastatic phenotype in breast cancer. Therefore, inhibitors of this pump have emerged as promising anticancer drugs. Lactoferrin (Lf) is a natural pro-apoptotic iron-binding glycoprotein with strong anticancer activity whose mechanism of action is not fully understood. Here, we show that bovine Lf (bLf) preferentially induces apoptosis in the highly metastatic breast cancer cell lines Hs 578T and MDA-MB-231, which display a prominent localisation of V-H+-ATPase at the plasma membrane, but not in the lowly metastatic T-47D or in the non-tumorigenic MCF-10-2A cell lines. We also demonstrate that bLf decreases the extracellular acidification rate and causes intracellular acidification in metastatic breast cancer cells and, much like the well-known proton pump inhibitors concanamycin A and bafilomycin A1, inhibits V-H+-ATPase in sub-cellular fractions. These data further support that bLf targets V-H+-ATPase and explain the selectivity of bLf for cancer cells, especially for highly metastatic breast cancer cells. Altogether, our results pave the way for more rational in vivo studies aiming to explore this natural non-toxic compound for metastatic breast cancer therapy.
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.|Centre of Biological Engineering (CEB), Department of Biological Engineering, University of Minho, Braga, Portugal.
authors.forename: Cátia S
authors.initials: CS
authors.lastname: Pereira
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.|Centre of Biological Engineering (CEB), Department of Biological Engineering, University of Minho, Braga, Portugal.
authors.forename: Joana P
authors.initials: JP
authors.lastname: Guedes
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Marília
authors.initials: M
authors.lastname: Gonçalves
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Loureiro
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Lisandra
authors.initials: L
authors.lastname: Castro
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.|Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Hernâni
authors.initials: H
authors.lastname: Gerós
authors.affiliation: Centre of Biological Engineering (CEB), Department of Biological Engineering, University of Minho, Braga, Portugal.
authors.forename: Lígia R
authors.initials: LR
authors.lastname: Rodrigues
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Côrte-Real
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000494:pharmacology* / Q000627:therapeutic use; D008099:Liver / Q000166:cytology; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D051381:Rats; D017207:Rats, Sprague-Dawley; D059016:Tumor Microenvironment / Q000187:drug effects*; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D018942:Macrolides; C036978:concanamycin A; C040929:bafilomycin A1; D007781:Lactoferrin; D025262:Vacuolar Proton-Translocating ATPases
keywords: V-H+-ATPase; V-H+-ATPase inhibitor; breast cancer; extracellular acidification rate; lactoferrin