BX-912

BX-912 is a potent and selective inhibitor of 3-phosphoinositide-dependent kinase 1 (PDK1) with IC50 value of 26nM [1]. BX-912 has shown 9-fold selectivity for PDK1 relative to PKA and 105-fold selectivity against PKC [1].

BX-912 has been revealed to suppress the MDA-468 cells (one kind of breast tumor cell expressing high levels of activated Akt) growth and increase caspase-3/7 activity. On the contrary, BX-912 had no effect on caspase-3/7 activation in normal primary PrECs and primary HMECs. Moreover, BX-912 has been demonstrated to induce cell cycle arrest of MDA-468 cells at the G2/M phase [1].

References:
[1] Feldman RI1, Wu JM, Polokoff MA, Kochanny MJ, Dinter H, Zhu D, Biroc SL, Alicke B, Bryant J, Yuan S, Buckman BO, Lentz D, Ferrer M, Whitlow M, Adler M, Finster S, Chang Z, Arnaiz DO. Novel small molecule inhibitors of 3-phosphoinositide-dependent kinase-1. J Biol Chem. 2005 May 20;280(20):19867-74. Epub 2005 Mar 16.

Evaluation of human microtubule affinity-regulating kinase 4 inhibitors: fluorescence binding studies, enzyme, and cell assays.[Pubmed:27748164]

J Biomol Struct Dyn. 2017 Nov;35(14):3194-3203.

Human microtubule affinity-regulating kinase 4 (MARK4) is considered as an encouraging drug target for the design and development of inhibitors to cure several life-threatening diseases such as Alzheimer disease, cancer, obesity, and type-II diabetes. Recently, we have reported four ligands namely, BX-912, BX-795, PKR-inhibitor, and OTSSP167 (hydrochloride) which bind preferentially to the two different constructs of human MARK4 containing kinase domain. To ensure the role of ubiquitin-associated (UBA) domain in the ligand binding, we made a newer construct of MARK4 which contains both kinase and UBA domains, named as MARK4-F3. We observed that OTSSP167 (hydrochloride) binds to the MARK4-F3 with a binding constant (K) of 3.16 x 10(6), M(-1) (+/-.21). However, UBA-domain of MARK4-F3 doesn't show any interaction with ligands directly as predicted by the molecular docking. To validate further, ATPase inhibition assays of all three constructs of MARK4 in the presence of mentioned ligands were carried out. An appreciable correlation between the binding experiments and ATPase inhibition assays of MARK4 was observed. In addition, cell-proliferation inhibition activity for all four ligands on the Human embryonic kidney (HEK-293) and breast cancer cell lines (MCF-7) was performed using MTT assay. IC50 values of OTSSP167 for HEK-293 and MCF-7 were found to be 58.88 (+/-1.5), and 48.2 (+/-1.6), respectively. OTSSP167 among all four inhibitors, showed very good enzyme inhibition activity against three constructs of MARK4. Moreover, all four inhibitors showed anti-neuroblastoma activity and anticancer properties. In conclusion, OTSSP167 may be considered as a promising scaffold to discover novel inhibitors of MARK4.

Designing New Kinase Inhibitor Derivatives as Therapeutics Against Common Complex Diseases: Structural Basis of Microtubule Affinity-Regulating Kinase 4 (MARK4) Inhibition.[Pubmed:26565604]

OMICS. 2015 Nov;19(11):700-11.

Drug development for common complex diseases is in need of new molecular entities and actionable drug targets. MAP/microtubule affinity-regulating kinase 4 (MARK4) is associated with numerous diseases such as neurodegenerative disorders, obesity, cancer, and type 2 diabetes. Understanding the structural basis of ligands' (inhibitors) and substrates' binding to MARK4 is crucial to design new kinase inhibitors for therapeutic purposes. This study reports new observations on docking three well-known kinase inhibitors in the kinase domain of MARK4 variants and the calculated binding affinity. These variants of MARK4 are named as MARK4-F1 (59 N-terminal residues along with kinase domain) and MARK4-F2 (kinase domain of MARK4). We additionally performed molecular dynamics (MD) simulation and fluorescence binding studies to calculate the actual binding affinity of kinase inhibitors, BX-912, BX-795, and OTSSP167 (hydrochloride) for the MARK4. Docking analyses revealed that ligands bind in the large hydrophobic cavity of the kinase domain of MARK4 through several hydrophobic and hydrogen-bonded interactions. Simulations suggested that OTSSP167 (hydrochloride) is forming a stable complex, and hence the best inhibitor of MARK4. Intrinsic fluorescence of MARK4 was significantly quenched by addition of ligands, indicating their potential binding to MARK4. A lower KD value of MARK4 with OTSSP167 (hydrochloride) suggested that it is a better interacting partner than BX-912 and BX-795. These data form a basis for designing novel and potent OTSSP167 (hydrochloride) derivatives as therapeutic candidates against common complex diseases. The inhibitors designed as such might possibly suppress the growth of tumor-forming cells and be potentially applied for treatment of a wide range of human cancers as well.

PDK1 in apical signaling endosomes participates in the rescue of the polarity complex atypical PKC by intermediate filaments in intestinal epithelia.[Pubmed:22398726]

Mol Biol Cell. 2012 May;23(9):1664-74.

Phosphorylation of the activation domain of protein kinase C (PKC) isoforms is essential to start a conformational change that results in an active catalytic domain. This activation is necessary not only for newly synthesized molecules, but also for kinase molecules that become dephosphorylated and need to be refolded and rephosphorylated. This "rescue" mechanism is responsible for the maintenance of the steady-state levels of atypical PKC (aPKC [PKCiota/lambda and zeta]) and is blocked in inflammation. Although there is consensus that phosphoinositide-dependent protein kinase 1 (PDK1) is the activating kinase for newly synthesized molecules, it is unclear what kinase performs that function during the rescue and where the rescue takes place. To identify the activating kinase during the rescue mechanism, we inhibited protein synthesis and analyzed the stability of the remaining aPKC pool. PDK1 knockdown and two different PDK1 inhibitors-BX-912 and a specific pseudosubstrate peptide-destabilized PKCiota. PDK1 coimmunoprecipitated with PKCiota in cells without protein synthesis, confirming that the interaction is direct. In addition, we showed that PDK1 aids the rescue of aPKC in in vitro rephosphorylation assays using immunodepletion and rescue with recombinant protein. Surprisingly, we found that in Caco-2 epithelial cells and intestinal crypt enterocytes PDK1 distributes to an apical membrane compartment comprising plasma membrane and apical endosomes, which, in turn, are in close contact with intermediate filaments. PDK1 comigrated with the Rab11 compartment and, to some extent, with the transferrin compartment in sucrose gradients. PDK1, pT555-aPKC, and pAkt were dependent on dynamin activity. These results highlight a novel signaling function of apical endosomes in polarized cells.

Novel small molecule inhibitors of 3-phosphoinositide-dependent kinase-1.[Pubmed:15772071]

J Biol Chem. 2005 May 20;280(20):19867-74.

The phosphoinositide 3-kinase/3-phosphoinositide-dependent kinase 1 (PDK1)/Akt signaling pathway plays a key role in cancer cell growth, survival, and tumor angiogenesis and represents a promising target for anticancer drugs. Here, we describe three potent PDK1 inhibitors, BX-795, BX-912, and BX-320 (IC(50) = 11-30 nm) and their initial biological characterization. The inhibitors blocked PDK1/Akt signaling in tumor cells and inhibited the anchorage-dependent growth of a variety of tumor cell lines in culture or induced apoptosis. A number of cancer cell lines with elevated Akt activity were >30-fold more sensitive to growth inhibition by PDK1 inhibitors in soft agar than on tissue culture plastic, consistent with the cell survival function of the PDK1/Akt signaling pathway, which is particularly important for unattached cells. BX-320 inhibited the growth of LOX melanoma tumors in the lungs of nude mice after injection of tumor cells into the tail vein. The effect of BX-320 on cancer cell growth in vitro and in vivo indicates that PDK1 inhibitors may have clinical utility as anticancer agents.

Phosphoinositide-dependent protein kinase 1 (PDK1) mediates potent inhibitory effects on eosinophils.[Pubmed:25645675]

Eur J Immunol. 2015 May;45(5):1548-59.

Prostaglandin E2 (PGE2 ) protects against allergic responses via binding to prostanoid receptor EP4, which inhibits eosinophil migration in a PI3K/PKC-dependent fashion. The phosphoinositide-dependent protein kinase 1 (PDK1) is known to act as a downstream effector in PI3K signaling and has been implicated in the regulation of neutrophil migration. Thus, here we elucidate whether PDK1 mediates inhibitory effects of E-type prostanoid receptor 4 (EP4) receptors on eosinophil function. Therefore, eosinophils were isolated from human peripheral blood or differentiated from mouse BM. PDK1 signaling was investigated in shape change, chemotaxis, CD11b, respiratory burst, and Ca(2+) mobilization assays. The specific PDK1 inhibitors BX-912 and GSK2334470 prevented the inhibition by prostaglandin E2 and the EP4 agonist ONO-AE1-329. Depending on the cellular function, PDK1 seemed to act through PI3K-dependent or PI3K-independent mechanisms. Stimulation of EP4 receptors caused PDK1 phosphorylation at Ser396 and induced PI3K-dependent nuclear translocation of PDK1. EP4-induced inhibition of shape change and chemotaxis was effectively reversed by the Akt inhibitor triciribine. In support of this finding, ONO-AE1-329 induced a PI3K/PDK1-dependent increase in Akt phosphorylation. In conclusion, our data illustrate a critical role for PDK1 in transducing inhibitory signals on eosinophil effector function. Thus, our results suggest that PDK1 might serve as a novel therapeutic target in diseases involving eosinophilic inflammation.

BX-912 is a direct, selective, and ATP-competitive PDK1 inhibitor (IC50=26 nM). BX-912 blocks PDK1/Akt signaling in tumor cells and inhibits the anchorage-dependent growth of a variety of tumor cell lines in culture or induces apoptosis.

BX-912,702674-56-4,Natural Products,PDK-1, buy BX-912 , BX-912 supplier , purchase BX-912 , BX-912 cost , BX-912 manufacturer , order BX-912 , high purity BX-912