title: Biological validation that SF3b is a target of the antitumor macrolide pladienolide.
abstract: Pladienolide is a naturally occurring macrolide that binds to the SF3b complex to inhibit mRNA splicing. It has not been fully validated whether the splicing impairment is a relevant mechanism for the potent antitumor activity of pladienolide. We established pladienolide-resistant clones from WiDr and DLD1 colorectal cancer cells that were insensitive to the inhibitory action of pladienolide on cell proliferation and splicing. An mRNA-Seq differential analysis revealed that these two cell lines have an identical mutation at Arg1074 in the gene for SF3B1, which encodes a subunit of the SF3b complex. Reverse expression of the mutant protein transferred pladienolide resistance to WiDr cells. Furthermore, immunoprecipitation analysis using a radiolabeled probe showed that the mutation impaired the binding affinity of paldienolide to its target. These results clearly demonstrate that pladienolide exerts its potent activity by targeting SF3b and also suggest that inhibition of SF3b is a promising drug target for anticancer therapy.
authors: Tsukuba Research Laboratories, Eisai Co., Ltd, Tsukuba, Ibaraki, Japan. a-yokoi@hhc.eisai.co.jp
authors: Akira
authors: A
authors: Yokoi
authors: Yoshihiko
authors: Y
authors: Kotake
authors: Kentaro
authors: K
authors: Takahashi
authors: Tadashi
authors: T
authors: Kadowaki
authors: Yoshiko
authors: Y
authors: Matsumoto
authors: Yukinori
authors: Y
authors: Minoshima
authors: Naoko H
authors: NH
authors: Sugi
authors: Koji
authors: K
authors: Sagane
authors: Makoto
authors: M
authors: Hamaguchi
authors: Masao
authors: M
authors: Iwata
authors: Yoshiharu
authors: Y
authors: Mizui
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004852:Epoxy Compounds / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D018942:Macrolides / Q000378:metabolism / Q000494:pharmacology*; D010750:Phosphoproteins / Q000187:drug effects* / Q000378:metabolism; D012326:RNA Splicing / Q000187:drug effects; D000072260:RNA Splicing Factors; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000187:drug effects* / Q000378:metabolism
chemical_list: D004852:Epoxy Compounds; D018942:Macrolides; D010750:Phosphoproteins; D000072260:RNA Splicing Factors; D017413:Ribonucleoprotein, U2 Small Nuclear; C112491:SF3B1 protein, human; C522342:pladienolide B