title: Protease activity at invadopodial focal digestive areas is dependent on NHE1-driven acidic pHe.
abstract: Degradation of the extracellular matrix (ECM) is a critical step of tumor cell invasion and requires protease-dependent proteolysis focalized at the invadopodia where the proteolysis of the ECM occurs. Most of the extracellular proteases belong to serine- or metallo-proteases and the invadopodia is where protease activity is regulated. While recent data looking at global protease activity in the growth medium reported that their activity and role in invasion is dependent on Na+/H+ exchanger 1 (NHE1)-driven extracellular acidification, there is no data on this aspect at the invadopodia, and an open question remains whether this acid extracellular pH (pHe) activation of proteases in tumor cells occurs preferentially at invadopodia. We previously reported that the NHE1 is expressed in breast cancer invadopodia and that the NHE1‑dependent acidification of the peri-invadopodial space is critical for ECM proteolysis. In the present study, using, for the first time, in situ zymography analysis, we demonstrated a concordance between NHE1 activity, extracellular acidification and protease activity at invadopodia to finely regulate ECM digestion. We demonstrated that: (i) ECM proteolysis taking place at invadopodia is driven by acidification of the peri-invadopodia microenvironment; (ii) that the proteases have a functional pHe optimum that is acidic; (iii) more than one protease is functioning to digest the ECM at these invadopodial sites of ECM proteolysis; and (iv) lowering pHe or inhibiting the NHE1 increases protease secretion while blocking protease activity changes NHE1 expression at the invadopodia.
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Maria Raffaella
authors: MR
authors: Greco
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Ester
authors: E
authors: Antelmi
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Giovanni
authors: G
authors: Busco
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Lorenzo
authors: L
authors: Guerra
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Rosa
authors: R
authors: Rubino
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Valeria
authors: V
authors: Casavola
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Stephan Joel
authors: SJ
authors: Reshkin
authors: Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, I-70126 Bari, Italy.
authors: Rosa Angela
authors: RA
authors: Cardone
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000473:pathology*; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D045744:Cell Line, Tumor; D022081:Cell Surface Extensions / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053511:Matrix Metalloproteinase 14 / Q000096:biosynthesis / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D009361:Neoplasm Invasiveness / Q000473:pathology; D010447:Peptide Hydrolases / Q000378:metabolism*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013450:Sulfones / Q000494:pharmacology; D013876:Thiophenes / Q000494:pharmacology
chemical_list: D000889:Anti-Arrhythmia Agents; D027682:Cation Transport Proteins; D006146:Guanidines; D061965:Matrix Metalloproteinase Inhibitors; C490998:SLC9A1 protein, human; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers; D013450:Sulfones; D013876:Thiophenes; D010649:Phenylalanine; C093373:cariporide; C080985:batimastat; D010447:Peptide Hydrolases; D002401:Cathepsin B; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14