BI-D1870 (501437-28-1) is an inhibitor of p90 ribosomal S6 kinase (RSK; IC50’s = RSK1, 31 nM; RSK2, 24 nM; RSK3, 18 nM; RSK4, 15 nM) with selectivity over other AGC kinases.1?It protected mice from experimental autoimmune encephalomyelitis suggesting a new strategy to treat multiple sclerosis.2?BI-D1870 has also been found to alter mTORC1 signaling in an RSK-independent manner.3?BI-D1870 induced apoptosis in oral squamous cell carcinoma cells4, suppressed growth and induced apoptosis in pediatric medulloblastoma cell lines as well as sensitizing these lines to Sonic hedgehog agents5, and blocked cell proliferation and protein synthesis in dual BRAF and MEK inhibitor-resistant melanoma6.
The 90 kDa ribosomal S6 kinases (RSKs) are a group of serine/threonine kinases involved in diverse cellular processes, including growth, survival, and motility. BI-D1870 is a cell permeable, ATP-competitive inhibitor of the four vertebrate isoforms of RSK, RSK1-4 (IC50s = 31, 24, 18, and 15 nM, respectively). At 100 nM, it also significantly inhibits polo-like kinase 1, Aurora B, maternal embryonic leucine zipper kinase, and mammalian STE20-like kinase 2. BI-D1870 acts at the N-terminal kinase domain, but not the C-terminal domain, of RSK.
This cell-permeant, ATP-competitive inhibitor (FW = 391.42 g/mol; CAS
501437-28-1: Solubility = 78 mg/mL DMSO; <1 mg/mL H2O), also known
as 2-[ (3,5-difluoro-4-hydroxyphenyl) amino]-7,8-dihydro-5,7-dimethyl-8- (3-
methylbutyl) -6 (5H) -pteridinone, targets the p90 Ribosomal protein S6
Kinase a-1, 2, 3, and 4, or RSK1, RSK2, RSK3, and RSK4, with IC50 values
of 31 nM, 24 nM, 18 nM, and 15 nM, respectively. RSK isoforms are
activated by Extracellular-signal-Regulated Kinases ERK1 and ERK2 in
response to growth factors, phorbol esters and other agonists. BI-D1870
shows 10x to 100x selectivity for RSK over MST2, GSK-3β, MARK3, CK1
and Aurora B protein kinases. When tested in vitro, BI-D1870 exhibits IC50
values for inhibits RSK1, RSK2, RSK3 and RSK4 are in the 10–30 nM.
Although assumed to be a remarkably specific inhibitor of RSK isoforms,
with a >500-fold greater selectivity over nine other AGC kinases, later work
assessing the ability of BI-D1870 to protect enzyme active sites from
alkylation demonstrated that several other kinases interact with BI-D1870
. Subsequent direct activity assays confirmed that Slk, Lok and Mst1
protein kinases are inhibited by BI-D1870 and that phosphorylation of some
of their substrates is blocked by BI-D1870 in living cells. Such results
suggest that the specificity of BI-D1870 cannot be taken for certain.
1) Gopal?et al. (2007),?BI-D1870 is a specific inhibitor of the p90 RSK (ribosomal S6 kinase) isoforms in vitro and in vivo; Biochem. J.?401 (Pt 1)?29
2) Takda?et al.?(2016),?The ribosomal S6 kinase inhibitor BI-D1870 ameliorated experimental autoimmune encephalomyelitis in mice;?Immunobiology?221?188
3) Roffe?et al.?(2015),?Two widely used RSK inhibitors, BI-D1870 and SL0101, alter mTORC1 signaling in a RSK-independent manner; Cell Signal.?27?1630
4) Chiu?et al.?(2014),?Antitumor effects of BI-D1870 on human oral squamous cell carcinoma; Cancer Chemother. Pharmacol.?73?237
5) Pambid?et al. (2014),?Overcoming resistance to Sonic hedgehog inhibition by targeting p90 ribosomal S6 kinase in pediatric medulloblastoma; Pediatr. Blood Cancer?61?107
6) Theodosakis?et al.?(2017),?p90RSK Blockade Inhibits Dual BRAF and MEK Inhibitor-Resistant Melanoma by Targeting Protein Synthesis; J. Invest. Dermatol.?137?2187
