Spliceostatin A blocks angiogenesis by inhibiting global gene expression including VEGF.
Spliceostatin A (SSA) is a methylated derivative of an antitumor natural product FR901464, which specifically binds and inhibits the SF3b spliceosome sub-complex. To investigate the selective antitumor activity of SSA, we focused on the regulation of vascular endothelial growth factor (VEGF) mRNA, since VEGF is a key regulatory component in tumor angiogenesis and known for the intricate regulation of mRNA processing, such as alternative splicing. We found that in HeLa cells SSA reduced the amount of both mRNA and protein of VEGF. Spliceostatin A not only inhibited the splicing reaction of VEGF pre-mRNA but also reduced the total amount of VEGF's transcripts, while SSA affected GAPDH mRNA to a lesser extent. Given a significant reduction in VEGF gene expression, SSA was expected to possess anti-angiogenic activity in vivo. Indeed, SSA inhibited cancer cell-derived angiogenesis in vivo in a chicken chorioallantoic membrane (CAM) assay. The inhibition of angiogenesis with SSA was abolished by addition of exogenous VEGF. We also performed global gene expression analyses of HeLa cells and found that the expression levels of 38% of total genes including VEGF decreased to <50% of the basal levels following 16 h of SSA treatment. These results suggest that the global interference of gene expression including VEGF in tumor cells is at least one of the mechanisms by which SSA (or FR901464) exhibits its strong antitumor activity.
Furumai
Ryohei
R
Chemical Genetics Laboratory Molecular Ligand Biology Research Team, Chemical Genomics Research Group, RIKEN Advanced Science Institute, Wako, Saitama, Japan.
Uchida
Kazuyo
K
Komi
Yusuke
Y
Yoneyama
Misao
M
Ishigami
Ken
K
Watanabe
Hidenori
H
Kojima
Soichi
S
Yoshida
Minoru
M
D020533:Angiogenesis Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D015394:Molecular Structure; D009389:Neovascularization, Pathologic / Q000235:genetics* / Q000378:metabolism / Q000517:prevention & control; D020411:Oligonucleotide Array Sequence Analysis; D011714:Pyrans / Q000737:chemistry / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013141:Spiro Compounds / Q000737:chemistry / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism
D020533:Angiogenesis Inhibitors; D011714:Pyrans; D013141:Spiro Compounds; D042461:Vascular Endothelial Growth Factor A; C553684:spliceostatin A