title: V-ATPase inhibition by archazolid leads to lysosomal dysfunction resulting in impaired cathepsin B activation in vivo.
abstract: The myxobacterial agent archazolid inhibits the vacuolar proton pump V-ATPase. V-ATPases are ubiquitously expressed ATP-dependent proton pumps, which are known to regulate the pH in endomembrane systems and thus play a crucial role in endo- and exocytotic processes of the cell. As cancer cells depend on a highly active secretion of proteolytic proteins in order to invade tissue and form metastases, inhibition of V-ATPase is proposed to affect the secretion profile of cancer cells and thus potentially abrogate their metastatic properties. Archazolid is a novel V-ATPase inhibitor. Here, we show that the secretion pattern of archazolid treated cancer cells includes various prometastatic lysosomal proteins like cathepsin A, B, C, D and Z. In particular, archazolid induced the secretion of the proforms of cathepsin B and D. Archazolid treatment abrogates the cathepsin B maturation process leading to reduced intracellular mature cathepsin B protein abundance and finally decreased cathepsin B activity, by inhibiting mannose-6-phoshate receptor-dependent trafficking. Importantly, in vivo reduced cathepsin B protein as well as a decreased proteolytic cathepsin B activity was detected in tumor tissue of archazolid-treated mice. Our results show that inhibition of V-ATPase by archazolid reduces the activity of prometastatic proteases like cathepsin B in vitro and in vivo.
authors.affiliation: Pharmaceutical Biotechnology Department of Pharmacy, Ludwig Maximilians University, Munich, Germany.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Kubisch
authors.forename: Thomas
authors.initials: T
authors.lastname: Fröhlich
authors.forename: Georg J
authors.initials: GJ
authors.lastname: Arnold
authors.forename: Laura
authors.initials: L
authors.lastname: Schreiner
authors.forename: Karin
authors.initials: K
authors.lastname: von Schwarzenberg
authors.forename: Andreas
authors.initials: A
authors.lastname: Roidl
authors.forename: Angelika M
authors.initials: AM
authors.lastname: Vollmar
authors.forename: Ernst
authors.initials: E
authors.lastname: Wagner
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002401:Cathepsin B / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008247:Lysosomes / Q000187:drug effects / Q000201:enzymology; D061986:MCF-7 Cells; D018942:Macrolides / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference; D017527:Receptor, IGF Type 2 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013844:Thiazoles / Q000494:pharmacology*; D047368:Tumor Burden / Q000187:drug effects; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: C541389:ATP6V0C protein, human; D018942:Macrolides; D017527:Receptor, IGF Type 2; D013844:Thiazoles; C519728:archazolid B; C034304:cation-dependent mannose-6-phosphate receptor; D002401:Cathepsin B; D025262:Vacuolar Proton-Translocating ATPases
keywords: V-ATPase; archazolid; cancer; cathepsin B; metastasis