title: Ro 31-6045, the inactive analogue of the protein kinase C inhibitor Ro 31-8220, blocks in vivo activation of p70(s6k)/p85(s6k): implications for the analysis of S6K signalling.
abstract: The mitogen-stimulated protein kinase p70(s6k)/p85(s6k) (S6K) plays an essential role in cell proliferation and growth, with inhibitors of the S6K signalling pathway showing promise as anti-tumour therapeutics. Here, we report that the bisindolylmaleimide derivative Ro 31-6045, previously reported to be inactive as a kinase inhibitor, inhibited S6K activity in vivo with an IC50=8 microM. Structure/function analysis using mutant forms of S6K indicates that Ro 31-6045 inhibition is independent of the upstream activator mTOR. Ro 31-6045 will prove useful in elucidating the complex activation mechanism of S6K and its independence from mTOR will allow confirmation of functional data obtained using the mTOR inhibitor rapamycin.
authors.affiliation: Trescowthick Research Laboratories, Peter MacCallum Cancer Institute, Locked Bag #1, A'Beckett Street, Melbourne, Vic., Australia.
authors.forename: Nelly
authors.initials: N
authors.lastname: Marmy-Conus
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Hannan
authors.forename: Richard B
authors.initials: RB
authors.lastname: Pearson
mesh_terms: D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D007546:Isoquinolines / Q000494:pharmacology; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016297:Mutagenesis, Site-Directed; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013449:Sulfonamides; D058570:TOR Serine-Threonine Kinases; D014162:Transfection
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D007546:Isoquinolines; D008301:Maleimides; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; C456939:Ro 31-6045; D013449:Sulfonamides; C071449:H 85; D011494:Protein Kinases; C546842:MTOR protein, human; C546843:mTOR protein, mouse; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases; D058570:TOR Serine-Threonine Kinases; D011493:Protein Kinase C; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D020123:Sirolimus; C064758:Ro 31-8220