title: Levels of SCS7/FA2H-mediated fatty acid 2-hydroxylation determine the sensitivity of cells to antitumor PM02734.
abstract: PM02734 is a novel synthetic antitumor drug that is currently in phase I clinical trials. To gain some insight into its mode of action, we used the yeast Saccharomyces cerevisiae as a model system. Treatment of S. cerevisiae with PM02734 rapidly induced necrosis-like cell death, as also found for mammalian cells treated with its close analogue kahalalide F. We have screened the complete set of 4,848 viable S. cerevisiae haploid deletion mutants to identify genes involved in sensitivity or resistance to PM02734. Forty-five percent of the 40 most sensitive strains identified had a role in intracellular vesicle trafficking, indicating that the drug severely affects this process. A mutant strain lacking the sphingolipid fatty acyl 2-hydroxylase Scs7 was found to be the most resistant to PM02734, whereas overexpression of Scs7 rendered the cells hypersensitive to PM02734. To validate these findings in human cells, we did small interfering RNA experiments and also overexpressed the Scs7 human homologue FA2H in human cancer cell lines. As in yeast, FA2H silencing turned the cells resistant to the drug, whereas FA2H overexpression led to an increased sensitivity. Moreover, exogenous addition of the 2-hydroxylated fatty acid 2-hydroxy palmitic acid to different human cell lines increased their sensitivity to the cytotoxic compound. Taken together, these results suggest that the cell membrane and, in particular, 2-hydroxy fatty acid-containing ceramides are important for PM02734 activity. These findings may have important implications in the development of PM02734 because tumor cells with high FA2H expression are expected to be particularly sensitive to this drug.
authors.affiliation: Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Herrero
authors.forename: Alma M
authors.initials: AM
authors.lastname: Astudillo
authors.forename: María A
authors.initials: MA
authors.lastname: Balboa
authors.forename: Carmen
authors.initials: C
authors.lastname: Cuevas
authors.forename: Jesús
authors.initials: J
authors.lastname: Balsinde
authors.forename: Sergio
authors.initials: S
authors.lastname: Moreno
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D019556:COS Cells; D048708:Cell Growth Processes / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002522:Chlorocebus aethiops; D047630:Depsipeptides / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology; D017353:Gene Deletion; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D006900:Hydroxylation / Q000187:drug effects; D006899:Mixed Function Oxygenases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; D047630:Depsipeptides; D005227:Fatty Acids; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D029701:Saccharomyces cerevisiae Proteins; C522358:elisidepsin; D006899:Mixed Function Oxygenases; C019081:fatty acid alpha-hydroxylase; C109314:Scs7 protein, S cerevisiae