Effective siRNA delivery and target mRNA degradation using an amphipathic peptide to facilitate pH-dependent endosomal escape.

Effective delivery of siRNA (small interfering RNA) into the cells requires the translocation of siRNA into the cytosol. One potential delivery strategy uses cell-delivery peptides that facilitate this step. In the present paper, we describe the characterization of an amphipathic peptide that mediates the uptake of non-covalently bound siRNA into cells and its subsequent release into the cytosol.

Quantitative evaluation of siRNA delivery in vivo.

Effective small interfering RNA (siRNA)-mediated therapeutics require the siRNA to be delivered into the cellular RNA-induced silencing complex (RISC). Quantitative information of this essential delivery step is currently inferred from the efficacy of gene silencing and siRNA uptake in the tissue. Here we report an approach to directly quantify siRNA in the RISC in rodents and monkey.

Allosteric inhibitors of Akt1 and Akt2: discovery of [1,2,4]triazolo[3,4-f][1,6]naphthyridines with potent and balanced activity.

A series of [1,2,4]triazolo[3,4-f][1,6]naphthyridine allosteric dual inhibitors of Akt1 and 2 have been developed. These compounds have been shown to have potent dual Akt1 and 2 cell potency. The representative compound 13 provided potent inhibitory activity against Akt1 and 2 in vivo in a mouse model.

The design and synthesis of potent and cell-active allosteric dual Akt 1 and 2 inhibitors devoid of hERG activity.

This letter details the attenuation of hERG in a class of Akt inhibitors through heteroatom insertions into aromatic rings. The development of a cell-active dual Akt 1 and 2 inhibitors devoid of hERG activity is discussed using structure-activity relationships.

Discovery of potent and cell-active allosteric dual Akt 1 and 2 inhibitors.

This paper describes the improvement of cell potency in a class of allosteric Akt 1 and 2 inhibitors. Key discoveries include identifying the solvent exposed region of the molecule and appending basic amines to enhance the physiochemical properties of the molecules. Findings from the structure-activity relationships are discussed.

Allosteric inhibitors of Akt1 and Akt2: a naphthyridinone with efficacy in an A2780 tumor xenograft model.

A series of naphthyridine and naphthyridinone allosteric dual inhibitors of Akt1 and 2 have been developed. These compounds have been optimized to have potent dual activity against the activated kinase as well as the activation of Akt in cells. One molecule in particular, compound 17, has potent inhibitory activity against Akt1 and 2 in vivo in a mouse lung and efficacy in a tumor xenograft model.

Rapid assembly of diverse and potent allosteric Akt inhibitors.

This paper describes the rapid assembly of four different classes of potent Akt inhibitors from a common intermediate. Among them, a pyridopyrimidine series displayed the best intrinsic and cell potency against Akt1 and Akt2. This series also showed a promising pharmacokinetic profile and excellent selectivity over other closely related kinases.

Optimization of 2,3,5-trisubstituted pyridine derivatives as potent allosteric Akt1 and Akt2 inhibitors.

This letter shows inhibitor SAR on a pyridine series of allosteric Akt inhibitors to optimize enzymatic and cellular potency. We have optimized 2,3,5-trisubstituted pyridines to give potent Akt1 and Akt2 inhibitors in both enzyme and cell based assays. In addition, we will also highlight the pharmacokinetic profile of an optimized inhibitor that has low clearance and long half-life in dogs.

The PI3K/Akt pathway: recent progress in the development of ATP-competitive and allosteric Akt kinase inhibitors.

This article describes recent advances in the development and biological evaluation of allosteric and ATP-competitive small molecule inhibitors for the serine/threonine kinase Akt (protein kinase B, PKB). Unregulated activation of the PI3K/Akt/PTEN pathway is a prominent feature of many human cancers and Akt is over-expressed or activated in all major cancers making Akt an exciting new target for cancer therapy. The development of Akt inhibitors has been complicated and hampered by the presence of three Akt isozymes, (Akt1, Akt2 and Akt3) which differ in function and tissue distribution, as well as a lack of Akt specific inhibitors.

Development of pyridopyrimidines as potent Akt1/2 inhibitors.

This communication reports a new synthetic route of pyridopyrimidines to facilitate their structural optimization in a library fashion and describes the development of pyridopyrimidines that have excellent enzymatic and cell potency against Akt1 and Akt2. This series also shows a high level of selectivity over other closely related kinases and significantly improved caspase-3 activity with the more optimized compounds.

Development of potent, allosteric dual Akt1 and Akt2 inhibitors with improved physical properties and cell activity.

This letter describes the development of potent, allosteric dual Akt1 and Akt2 inhibitors with improved aqueous solubility (approximately 18 mg/mL) that translates into enhanced cell activity and caspase-3 induction.

Recent progress in the development of ATP-competitive and allosteric Akt kinase inhibitors.

This article describes recent advances in the development and biological evaluation of small molecule inhibitors for the serine/threonine kinase Akt (PKB). Akt plays a pivotal role in cell survival and proliferation through a number of downstream effectors. Recent studies indicate that unregulated activation of the PI3K/Akt pathway is a prominent feature of many human cancers and Akt is over-expressed or activated in all major cancers.

The Akt/PKB family of protein kinases: a review of small molecule inhibitors and progress towards target validation.

This article describes recent advances in the development and biological evaluation of small molecule inhibitors for the serine/threonine kinase Akt (PKB). Akt plays a pivotal role in cell survival and proliferation through a number of downstream effectors. Recent studies indicate that unregulated activation of the PI3K/Akt pathway is a prominent feature of many human cancers and Akt is over-expressed or activated in all major cancers.

Tumor cell sensitization to apoptotic stimuli by selective inhibition of specific Akt/PKB family members.

Recent studies indicate that dysregulation of the Akt/PKB family of serine/threonine kinases is a prominent feature of many human cancers. The Akt/PKB family is composed of three members termed Akt1/PKBalpha, Akt2/PKBbeta, and Akt3/PKBgamma. It is currently not known to what extent there is functional overlap between these family members.

Discovery of 2,3,5-trisubstituted pyridine derivatives as potent Akt1 and Akt2 dual inhibitors.

This letter describes the discovery of a novel series of dual Akt1/Akt2 kinase inhibitors, based on a 2,3,5-trisubstituted pyridine scaffold. Compounds from this series, which contain a 5-tetrazolyl moiety, exhibit more potent inhibition of Akt2 than Akt1.

Allosteric Akt (PKB) inhibitors: discovery and SAR of isozyme selective inhibitors.

This letter describes the development of two series of potent and selective allosteric Akt kinase inhibitors that display an unprecedented level of selectivity for either Akt1, Akt2 or both Akt1/Akt2. An iterative analog library synthesis approach quickly provided a highly selective Akt1/Akt2 inhibitor that induces apoptosis in tumor cells and inhibits Akt phosphorylation in vivo.

Identification and characterization of pleckstrin-homology-domain-dependent and isoenzyme-specific Akt inhibitors.

We developed a high-throughput HTRF (homogeneous time-resolved fluorescence) assay for Akt kinase activity and screened approx. 270000 compounds for their ability to inhibit the three isoforms of Akt. Two Akt inhibitors were identified that exhibited isoenzyme specificity.