Compound #41 Targets Acute Myelogenous Leukemia by Inhibiting the Wnt/β-catenin Signaling Pathway.

Background/aim: Aberrant activation of the Wnt/β-catenin signaling pathway contributes to the pathogenesis of acute myelogenous leukemia (AML). Thus, targeting this pathway offers a promising therapeutic strategy against AML. Here, we synthesized a novel dipeptide-type inhibitor of the Wnt/β-catenin signaling pathway, compound #41, and explored its anti-tumor effects on AML cells.

Mechanistic Insights into the Effect of Sodium Iodide on Copper-Mediated Iododeboronation.

The copper-catalyzed Chan-Evans-Lam (CEL) coupling reaction advances carbon-heteroatom cross-coupling and has facilitated the development of radiohalogenation methodologies in radiochemistry. This study investigated the mechanisms and side reactions of CEL iodination under conditions relevant to radiosynthesis and typical organic synthesis, focusing on the effects of sodium iodide. The concentrations of copper and iodide, as well as the copper-to-iodide ratio, were identified as significant factors for successful copper-mediated CEL iodination, influencing the reaction mechanisms and side reactions.

Evaluating a Retro-Inverso Type Inhibitor of HTLV-1 Protease as a Competitive Inhibitor.

The inhibition mode of a retro-inverso (RI) inhibitor containing a hydroxyethylamine dipeptide isostere against the human T-cell leukemia virus type-1 (HTLV-1) protease was examined. Enzymatic evaluation of the RI-modified inhibitor containing a D-allo-Ile residue revealed that HTLV-1 was competitively inhibited. IC values of the RI-modified inhibitor and pepstatin A, a standard inhibitor of aspartic proteases, were nearly equivalent.

Synthesis and Biological Evaluation of a Novel Sugar-Conjugated Platinum(II) Complex Having a Tumor-Targeting Effect.

We designed and synthesized a novel platinum complex conjugated with 2-fluorinated 2-deoxyglucoside, named FGC-Pt, to capitalize on the Warburg effect and metabolic trapping properties of [F]2-deoxy-2-fluoro-d-glucose (FFDG). Then, we conducted comprehensive in vitro and in vivo studies to evaluate the effects of FGC-Pt. In vitro cytotoxicity assays using HeLa cells revealed that FGC-Pt exhibited concentration-dependent cytotoxicity, even though its cytotoxic effect was less pronounced than that of cisplatin.

One-pot two-step radioiodination based on copper-mediated iododeboronation and azide-alkyne cycloaddition reaction.

This methodology demonstrates the ability to sequentially regulate copper-mediated radioiododeboronation and an azide-alkyne cycloaddition reaction, which facilitates the continuous incorporation of reagents into the reaction system and mediates the integration of the purification steps into the final process. Additionally, this reaction is suited to be conducted under mild conditions and yields target compounds through potent radiochemical conversions.

Effect of Water on Direct Radioiodination of Small Molecules/Peptides Using Copper-Mediated Iododeboronation in Water-Alcohol Solvent.

Direct radioiodination of peptides using copper-mediated iododeboronation is a promising radiosynthetic method for solving issues of classical direct radiolabeling, such as toxicity of the organotin precursor (iododestannylation) or formation of radio byproducts (by electrophilic iodination of a tyrosine residue). However, the parameters for optimizing the reaction conditions for various peptides are not completely understood. In particular, considering peptide solubility, the effects of water-containing solvents on labeling efficiency should be thoroughly investigated.

Development of an activity-based chemiluminogenic probe for γ-glutamylcyclotransferase.

While γ-glutamylcyclotransferase (GGCT) has been implicated in cancer-cell proliferation, the role of GGCT enzymatic activity in the regulation of cancer-cell growth remains unclear. Toward further understanding of GGCT , here we report a novel cell-permeable chemiluminogenic probe "MAM-LISA-103" that detects intracellular GGCT activity and apply it to imaging. We first developed a chemiluminogenic probe LISA-103, which simply and sensitively detects the enzymatic activity of recombinant GGCT through chemiluminescence.

7,8-Dihydroxy-3-(4'-hydroxyphenyl)coumarin inhibits invasion and migration of osteosarcoma cells.

Advances in pharmacy and medicine have led to the development of many anti-cancer and molecular targeted agents; however, there are few agents capable of suppressing metastasis. To prevent cancer recurrence, it is essential to develop novel agents for inhibiting metastasis. Coumarin-based compounds have multiple pharmacological activities including anti-cancer effects.

Copper-mediated radioiodination and radiobromination via aryl boronic precursor and its application to I/Br-labeled prostate-specific membrane antigen imaging probes.

Prostate-specific membrane antigen (PSMA), expressed in prostate cancer cells, is being investigated extensively worldwide as a target for imaging and therapy of prostate cancer. Various radioiodinated PSMA imaging probes have been developed, and their structure has a peptidomimetic urea-based skeleton as a pharmacophore. For direct radioiodination of molecules containing these peptidomimetic structures, prior studies performed radioiododestannylation or electrophilic radioiodination of tyrosine residues.

The Effects of Side-Chain Configurations of a Retro-Inverso-Type Inhibitor on the Human T-Cell Leukemia Virus (HTLV)-1 Protease.

In this study, the effects of side-chain configurations of D-Ile residues of a retro-inverso (RI)-type inhibitor on the human T-cell leukemia virus type 1 (HTLV-1) protease containing a hydroxyethylamine dipeptide isostere were clarified. Prior to evaluation using the RI-type inhibitor, the effects of side-chain configurations of Ile residues of the substrate peptide on the HTLV-1 protease were examined to estimate the influence of side-chain configurations on enzyme activity. Based on the estimation of the influence of side-chain configurations on protease affinity, the RI-type inhibitors containing a D-allo-Ile residue in the corresponding substrate sequence, instead of a D-Ile residue, were synthesized via 9-fluorenylmethoxycarbonyl-based solid-phase peptide synthesis.

Macrocyclic BACE1 inhibitors with hydrophobic cross-linked structures: Optimization of ring size and ring structure.

Based on the X-ray crystallography of recombinant BACE1 and a hydroxyethylamine-type peptidic inhibitor, we introduced a cross-linked structure between the P1 and P3 side chains of the inhibitor to enhance its inhibitory activity. The P1 and P3 fragments bearing terminal alkenes were synthesized, and a ring-closing metathesis of these alkenes was used to construct the cross-linked structure. Evaluation of ring size using P1 and P3 fragments with various side chain lengths revealed that 13-membered rings were optimal, although their activity was reduced compared to that of the parent compound.

Structure-activity relationship study of hydroxyethylamine isostere and P1' site structure of peptide mimetic BACE1 inhibitors.

An aromatic substituent has been introduced into a known hydroxyethylamine (HEA)-type BACE1 inhibitor containing the superior substrate sequence to enhance inhibitory activity. The HEA-type isosteres bearing different hydroxyl group and methyl group configurations were prepared through a branched synthesis approach using intra- and inter-molecular epoxide opening reactions. The effect of their configuration was evaluated, showing that an R-configuration improved the inhibitory activity, while introduction of a methyl group on the isostere decreased the activity.

Copper-mediated radioiodination reaction through aryl boronic acid or ester precursor and its application to direct radiolabeling of a cyclic peptide.

A copper-mediated radioiodination using aryl boronic precursors is attracting attention as a solution to oxidative iododestannylation and nickel-mediated radioiodination drawbacks. The copper-mediated radiolabeling method allows radioiodination at room temperature with stable aryl boronic precursors without preparing complex starting materials or reagents and can be performed in a reaction vessel exposed to air. This method has good potential in radiochemistry; however, studies on the scope of copper-mediated radioiodination through boronic precursors are insufficient.

Synthesis of (+)-Muconin via Diastereoselective Oxypalladation.

Synthesis of (+)-muconin isolated from (Annonaceae) was achieved. Stereoselective construction of a tetrahydrofuran-terahydropyran (THF-THP) ring moiety was performed using diastereoselective oxypalladation in the presence of CuCl. The cross-coupling reaction of the THF-THP moiety with the γ-lactone portion followed by reduction of the enyne and removal of the protecting groups afforded (+)-muconin.

Synthesis of (+)-solenopsin via Pd-catalyzed N-alkylation and cyclization.

Synthesis of (+)-solenopsin, a 2,6-disubstituted piperidine alkaloid, isolated from fire ants (Solenopsis), was achieved. Stereoselective construction of trans-2,6-piperidine ring moiety was performed using palladium-catalyzed cyclization. Chain elongation using Grubbs 2nd catalyst followed by the reduction of double bond and the deprotection of the Cbz group afforded (+)-solenopsin.

Inhibitory effects of cynaropicrin and related sesquiterpene lactones from leaves of artichoke (Cynara scolymus L.) on induction of iNOS in RAW264.7 cells and its high-affinity proteins.

The methanolic extract of the leaves of artichoke (Cynara scolymus L.) was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

A novel dipeptide type inhibitor of the Wnt/β-catenin pathway suppresses proliferation of acute myelogenous leukemia cells.

The Wnt/β-catenin pathway is an attractive target for the treatment of acute myelogenous leukemia (AML), since aberrant activation of the Wnt/β-catenin pathway contributes to carcinogenesis in various types of cancers including AML. Screening of an in-house compound library, constructed at Kyoto Pharmaceutical University, identified a novel compound designated "31" that was found to be an inhibitor of the Wnt/β-catenin pathway. The compound inhibited T-cell factor (TCF) activity in a TCF firefly luciferase-reporter assay and suppressed the proliferation of several human AML cell lines in a dose-dependent manner.

Evaluation of an octahydroisochromene scaffold used as a novel SARS 3CL protease inhibitor.

An octahydroisochromene scaffold has been introduced into a known SARS 3CL protease inhibitor as a novel hydrophobic core to interact with the S2 pocket of the protease. An alkyl or aryl substituent was also introduced at the 1-position of the octahydroisochromene scaffold and expected to introduce additional interactions with the protease. Sharpless-Katsuki asymmetric epoxidation and Sharpless asymmetric dihydroxylation were employed to construct the octahydroisochromene scaffold.

Convergent Synthesis of trans-2,6-Disubstituted Piperidine Alkaloid, (-)-iso-6-Spectaline by Palladium-Catalyzed Cyclization.

The plant alkaloids, iso-6-spectaline and spectaline, isolated from the Cassia or Senna genera contain a characteristic 2,6-disubstituted piperidin-3-ol scaffold. Although both natural products are reported to exhibit a variety of interesting biological activities, few stereo-selective schemes for the construction of the 2,6-disubstituted scaffold have been reported. Following our previous studies regarding the synthesis of (+)-spectaline, herein we report the first convergent synthesis of (-)-iso-6-spectaline using a cross-metathesis under thermal conditions where the cis-2,6-disubstituted piperidin-3-ol scaffold is condensed with a long alkyl chain containing a terminal olefin.

Evaluation of a non-prime site substituent and warheads combined with a decahydroisoquinolin scaffold as a SARS 3CL protease inhibitor.

A non-prime site substituent and warheads combined with a decahydroisoquinolin scaffold was evaluated as a novel inhibitor for severe acute respiratory syndrome (SARS) chymotrypsin-like protease (3CL). The decahydroisoquinolin scaffold has been demonstrated to be an effective hydrophobic center to interact with S2 site of SARS 3CL, but the lack of interactions at S3 to S4 site is thought to be a major reason for the moderate inhibitory activity. In this study, the effects of an additional non-prime site substituent on the scaffold as well as effects of several warheads are evaluated.

Epicatechin oligomers longer than trimers have anti-cancer activities, but not the catechin counterparts.

Since procyanidins (oligomeric catechin or epicatechin) were reported to exhibit health benefits, much attention has been paid to the synthesis of these compounds, especially those that are longer than trimers. In the present study, syntheses of cinnamtannin A3 (epicatechin pentamer), A4 (epicatechin hexamer), catechin tetramer, pentamer, arecatannin A2 (epicatechin-epicatechin-epicatechin-catechin) and A3 (epicatechin-epicatechin-epicatechin-epicatechin-catechin) were achieved. The key reaction was a Lewis acid mediated equimolar condensation.

Effects of replacement and addition of an amino acid contained in a cyclic peptide corresponding to a β-hairpin loop sequence of human EGF receptor.

Effects of replacement and addition of an amino acid in a cyclic decapeptide 1 (cyclic-CYNPTTYQMC) for inhibitory activity to dimerization of human epidermal growth factor receptor (EGFR) were examined. By alanine scanning of 1 corresponding to the arm structure (residues 246-254) of a β-hairpin loop sequence (residues 242-259) of EGFR, it was confirmed that replacement of any amino acid in the loop structure lowered the dimerization inhibitory activity of 1. Among the residues examined, Tyr at position 246 and Thr at 250 were found to be crucial for dimer formation.

Structural basis for the development of SARS 3CL protease inhibitors from a peptide mimic to an aza-decaline scaffold.

Design of inhibitors against severe acute respiratory syndrome (SARS) chymotrypsin-like protease (3CL(pro) ) is a potentially important approach to fight against SARS. We have developed several synthetic inhibitors by structure-based drug design. In this report, we reveal two crystal structures of SARS 3CL(pro) complexed with two new inhibitors based on our previous work.

Evaluation of transition-state mimics in a superior BACE1 cleavage sequence as peptide-mimetic BACE1 inhibitors.

A superior substrate sequence for BACE1 containing transition-state mimics at the scissile site was evaluated as a protease inhibitor. Hydroxymethylcarbonyl (HMC) and hydroxyethylamine (HEA) isosteres were selected as the transition state mimics, and incorporated into the scissile site of the superior sequence covering the P4 to P1' sites (Glu-Ile-Thi-Thi(*)Nva; (*)denotes the cleavage site). Isosteres having different absolute configurations of the hydroxyl group were synthesized separately, and the effect of the configuration was evaluated.