Interaction of CDK12 with NXF1 is a new node for the linking mechanism between transcription and transportation of mRNA.

The transcription and transportation of mRNA are coupled processes; however, the mechanisms linking these processes remain unclear. Additionally, the significance of this connection in cancer drug development is poorly understood. To address these issues, we investigated the role of CDK12 kinase, which regulates RNA transcription through the phosphorylation of RNA polymerase II (Pol II) and has a repeated serine-arginine dipeptide (RS domain) involved in mRNA transport.

Different Degradation Mechanisms of Inhibitor of Apoptosis Proteins (IAPs) by the Specific and Nongenetic IAP-Dependent Protein Eraser (SNIPER).

Targeted protein degradation by small molecules is an emerging modality with significant potential for drug discovery. We previously developed chimeric molecules, termed specific and non-genetic inhibitor of apoptosis protein (IAP)-dependent protein erasers (SNIPERs), which induce the ubiquitylation and proteasomal degradation of target proteins. This degradation is mediated by the IAPs; the target proteins include bromodomain-containing protein 4 (BRD4), an epigenetic regulator protein.

Pharmacological difference between degrader and inhibitor against oncogenic BCR-ABL kinase.

Chronic myelogenous leukemia (CML) is characterized by the oncogenic fusion protein, BCR-ABL protein kinase, against which clinically useful inhibitors have been developed. An alternative approach to treat CML is to degrade the BCR-ABL protein. Recently, potent degraders against BCR-ABL have been developed by conjugating dasatinib to ligands for E3 ubiquitin ligases.

Derivatization of inhibitor of apoptosis protein (IAP) ligands yields improved inducers of estrogen receptor α degradation.

Aberrant expression of proteins often underlies many diseases, including cancer. A recently developed approach in drug development is small molecule-mediated, selective degradation of dysregulated proteins. We have devised a protein-knockdown system that utilizes chimeric molecules termed specific and nongenetic IAP-dependent protein erasers (SNIPERs) to induce ubiquitylation and proteasomal degradation of various target proteins.

Targeting the Allosteric Site of Oncoprotein BCR-ABL as an Alternative Strategy for Effective Target Protein Degradation.

Protein degradation technology based on hybrid small molecules is an emerging drug modality that has significant potential in drug discovery and as a unique method of post-translational protein knockdown in the field of chemical biology. Here, we report the first example of a novel and potent protein degradation inducer that binds to an allosteric site of the oncogenic BCR-ABL protein. BCR-ABL allosteric ligands were incorporated into the SNIPER (Specific and Nongenetic inhibitor of apoptosis protein [IAP]-dependent Protein Erasers) platform, and a series of biological assays of binding affinity, target protein modulation, signal transduction, and growth inhibition were carried out.

Development of protein degradation inducers of oncogenic BCR-ABL protein by conjugation of ABL kinase inhibitors and IAP ligands.

Chromosomal translocation occurs in some cancer cells, which results in the expression of aberrant oncogenic fusion proteins that include BCR-ABL in chronic myelogenous leukemia (CML). Inhibitors of ABL tyrosine kinase, such as imatinib and dasatinib, exhibit remarkable therapeutic effects, although emergence of drug resistance hampers the therapy during long-term treatment. An alternative approach to treat CML is to downregulate the BCR-ABL protein.

Knockdown of Pathogenic Proteins via pecific and ongenetic nhibitor of Apoptosis Protein (IAP)-dependent rotein asers (SNIPERs).

Many diseases, especially cancers, result from aberrant or overexpression of pathogenic proteins. Specific inhibitors against these proteins have shown remarkable therapeutic effects, but these are limited mainly to enzymes. An alternative approach that may have utility in drug development relies on selective degradation of pathogenic proteins via small chimeric molecules linking an E3 ubiquitin ligase to the targeted protein for proteasomal degradation.

Fragment-based drug discovery of potent and selective MKK3/6 inhibitors.

The MAPK signaling cascade, comprised of several linear and intersecting pathways, propagates signaling into the nucleus resulting in cytokine and chemokine release. The Map Kinase Kinase isoforms 3 and 6 (MKK3 and MKK6) are responsible for the phosphorylation and activation of p38, and are hypothesized to play a key role in regulating this pathway without the redundancy seen in downstream effectors. Using FBDD, we have discovered efficient and selective inhibitors of MKK3 and MKK6 that can serve as tool molecules to help further understand the role of these kinases in MAPK signaling, and the potential impact of inhibiting kinases upstream of p38.

(-)-Ternatin inhibits adipogenesis and lipid metabolism in 3T3-L1 cells.

(-)-Ternatin, a highly N-methylated cyclic peptide, inhibits fat accumulation in 3T3-L1 cells and reduces fat mass in mice. However, the mechanism for its anti-adipogenic effect has remained unknown. To examine the mechanism used by (-)-ternatin to inhibit adipocyte differentiation, we examined the effects of (-)-ternatin and [l-Ala(4)]ternatin, an inactive analog of (-)-ternatin, on the expression of adipocyte markers and lipogenic enzymes.

Importance of the backbone conformation of (-)-ternatin in its fat-accumulation inhibitory activity against 3T3-L1 adipocytes.

Key relationships between the intramolecular H-bond-derived backbone conformation and the bioactivity of the novel fat-accumulation inhibitor (-)-ternatin are examined by analyses of the NMR spectroscopic data and CD spectra of designed analogues. The results reveal that the beta-turn structure of (-)-ternatin is responsible for its potent fat-accumulation inhibitory effect against 3T3-L1 murine adipocytes.

Structure-based hybridization of the bioactive natural products rhizonin A and ternatin leading to a selective fat-accumulation inhibitor against 3T3-L1 adipocytes.

Based on the structural similarity between the naturally occurring cyclic heptapeptides rhizonin A and ternatin, two novel analogues were designed. The synthetic analogues were assessed with regard to their fat-accumulation inhibitory effect against 3T3-L1 adipocytes, and this led to the discovery of a potent and selective fat-accumulation inhibitor compared to the parent compound rhizonin A.

Design, synthesis, and biological evaluation of biotin-labeled (-)-ternatin, a potent fat-accumulation inhibitor against 3T3-L1 adipocytes.

The design, synthesis, and biological activity of biotin-labeled (-)-ternatin are reported. Chemical modification, that is, biotinylation, was conducted using Click chemistry at the 6-position (NMe-D-ProGly moiety), which was a plausible location selected on the basis of our SAR studies. The compound displayed sufficient fat-accumulation inhibitory effect against 3T3-L1 adipocytes for further bio-organic studies.

Whole structure-activity relationships of the fat-accumulation inhibitor (-)-ternatin: recognition of the importance of each amino acid residue.

A series of Ala and Aoc analogues of (-)-ternatin were prepared, and their bioactivities were assessed by a fat-accumulation inhibition assay using 3T3-L1 adipocytes, which led to the discovery of key structure-activity relationships (SAR).

Biological activity, structural features, and synthetic studies of (-)-ternatin, a potent fat-accumulation inhibitor of 3T3-L1 adipocytes.

A series of studies, including preliminary screening, isolation, structure determination, synthesis, and biological evaluation, of (-)-ternatin (1) are described. A highly N-methylated cyclic heptapeptide isolated from the mushroom Coriolus versicolor, 1 shows an inhibitory effect on fat accumulation by 3T3-L1 murine adipocytes (EC50 = 0.02 microg mL(-1)).

Synthesis and inhibitory effect on fat accumulation of (-)-ternatin derivatives modified in the beta-OH-D-Leu(7) moiety.

An efficient synthesis of (-)-ternatin derivatives directed toward their SAR at the beta-OH-D-Leu(7) moiety and their biological activities against 3T3-L1 murine adipocytes are described.

Convergent synthesis and in vivo inhibitory effect on fat accumulation of (-)-ternatin, a highly N-methylated cyclic peptide.

(-)-Ternatin (1), a highly N-methylated cyclic heptapeptide, is a potent inhibitor of fat accumulation against 3T3-L1 murine adipocytes (EC50 = 0.14 microg/mL) [Shimokawa, K.; Mashima, I.