Antisense phosphorothioate oligonucleotides specifically down-regulate cdc25B causing S-phase delay and persistent antiproliferative effects.
Cell cycle progression in mammalian cells is regulated by a family of cyclin-dependent kinases (cdks) that are activated by a family of 3 cdc25 phosphatases: cdc25A, cdc25B and cdc25C. We examined the expression of mRNA and protein of all 3 cdc25s during the HeLa cell cycle, and found that cdc25B protein has a unique and limited pattern of expression relative to other cdc25 homologs. Antisense oligonucleotides reduced cdc25B mRNA levels and dysregulated protein expression, while inhibiting S-phase progression in synchronized HeLa cells. Scrambled control oligonucleotides had no effect. Antisense oligonucleotides transfected in early G2-phase had no effect on cell cycle progression. A direct correlation between down-regulation of cdc25B and inhibition of thymidine incorporation was found using several oligonucleotides. Our results suggest a role for cdc25B in S-phase and demonstrate that inhibition of cdc25B has persistent antiproliferative effects.
Garner-Hamrick
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PA
Cell and Molecular Biology, Pharmacia and Upjohn, Inc., Kalamazoo, MI 49001, USA.
Fisher
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C
D017398:Alternative Splicing; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects; D006367:HeLa Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007536:Isomerism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D016196:S Phase / Q000187:drug effects* / Q000502:physiology; D012680:Sensitivity and Specificity; D013873:Thionucleotides / Q000494:pharmacology*; D020687:cdc25 Phosphatases
D018797:Cell Cycle Proteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D013873:Thionucleotides; D010749:Phosphoprotein Phosphatases; C517008:CDC25B protein, human; D020687:cdc25 Phosphatases