Michiyasu Nakao

Pim-2 kinase is an important target of treatment for tumor progression and bone loss in myeloma.

Pim-2 kinase is overexpressed in multiple myeloma (MM) cells to enhance their growth and survival, and regarded as a novel therapeutic target in MM. However, the impact of Pim-2 inhibition on bone disease in MM remains unknown. We demonstrated here that Pim-2 expression was also upregulated in bone marrow stromal cells and MC3T3-E1 preosteoblastic cells in the presence of cytokines known as the inhibitors of osteoblastogenesis in MM, including interleukin-3 (IL-3), IL-7, tumor necrosis factor-α, transforming growth factor-β (TGF-β) and activin A, as well as MM cell conditioned media. The enforced expression of Pim-2 abrogated in vitro osteoblastogenesis by BMP-2, which suggested Pim-2 as a negative regulator for osteoblastogenesis. Treatment with Pim-2 short-interference RNA as well as the Pim inhibitor SMI-16a successfully restored osteoblastogenesis suppressed by all the above inhibitory factors and MM cells. The SMI-16a treatment potentiated BMP-2-mediated anabolic signaling while suppressing TGF-β signaling. Furthermore, treatment with the newly synthesized thiazolidine-2,4-dione congener, 12a-OH, as well as its prototypic SMI-16a effectively prevented bone destruction while suppressing MM tumor growth in MM animal models. Thus, Pim-2 may have a pivotal role in tumor progression and bone loss in MM, and Pim-2 inhibition may become an important therapeutic strategy to target the MM cell–bone marrow interaction.

Studies on the anorectic effect of N-acylphosphatidylethanolamine and phosphatidylethanolamine in mice.

N-acyl-phosphatidylethanolamine is a precursor phospholipid for anandamide, oleoylethanolamide, and other N-acylethanolamines, and it may in itself have biological functions in cell membranes. Recently, N-palmitoyl-phosphatidylethanolamine (NAPE) has been reported to function as an anorectic hormone secreted from the gut and acting on the brain (Gillum et al., [5]). In the current study, two of our laboratories independently investigated whether NAPE metabolites may be involved in mediating the anorectic action of NAPE i.p. injected in mice. Thus, the anorectic activity of a non-hydrolysable NAPE analogue, having ether bonds instead of ester bonds at sn1 and sn2 was compared with that of NAPE in molar equivalent doses. Furthermore, the anorectic effect of NAPE in NAPE-hydrolysing phospholipase D knockout animals was investigated. As negative controls, the NAPE precursor phosphatidylethanolamine and the related phospholipids phosphatidylcholine and phosphatidic acid were also tested. All compounds except one were found to inhibit food intake, raising the possibility that the effect of NAPE is non-specific.

Evaluation of Inhibitory Actions of Flavonols and Related Substances on Lysophospholipase D Activity of Serum Autotaxin by a Convenient Assay Using a Chromogenic Substrate

Overproduction of lysophosphatidic acid (LPA) by lysophospholipase D/autotaxin (lysoPLD/ATX) is postulated to be involved in the promotion of cancer and atherosclerosis. A lysoPLD inhibitor may be utilized to ameliorate the LPA-related pathological conditions. In this study, a new assay was devised to quantify p-nitrophenol from hydrolysis of chromogenic substrate by serum lysoPLD without tedious lipid extraction procedures. Flavonols, phenolic acids, free fatty acids, and N-acyltyrosines inhibited lysoPLD activity in a micromolar range. They were classified into competitive, noncompetitive, or mixed type inhibitors. The results show that the low hydrophobicity of an inhibitor is a critical factor in its preference for the binding to a noncatalytic binding site over a catalytic binding site. Considering its reported bioavailability and the low dependency of its inhibitory activity on serum dilution, flavonol is likely to be a more effective lysoPLD inhibitor in human blood circulation in vivo than the other inhibitors including LPA.

USE OF DIKETOPIPERAZINES FOR DETERMINING ABSOLUTE CONFIGURATIONS OF α-SUBSTITUTED SERINES BY 1H-NMR SPECTROSCOPY

A chiral α-substituted serine of interest was transformed into both of the corresponding diastereomers of diketopiperazines utilizing L- and D-phenylalanine methyl ester hydrochloride. The absolute configuration of the original chiral α-substituted serine was determined by 1 H-NMR analyses of the resulting diastereomers.

Unique anti-myeloma activity by thiazolidine-2,4-dione compounds with Pim inhibiting activity

Proviral Integrations of Moloney virus 2 (PIM2) is overexpressed in multiple myeloma (MM) cells, and regarded as an important therapeutic target. Here, we aimed to validate the therapeutic efficacy of different types of PIM inhibitors against MM cells for their possible clinical application. Intriguingly, the thiazolidine‐2,4‐dione‐family compounds SMI‐16a and SMI‐4a reduced PIM2 protein levels and impaired MM cell survival preferentially in acidic conditions, in contrast to other types of PIM inhibitors, including AZD1208, CX‐6258 and PIM447. SMI‐16a also suppressed the drug efflux function of breast cancer resistance protein, minimized the sizes of side populations and reduced in vitro colony‐forming capacity and in vivo tumourigenic activity in MM cells, suggesting impairment of their clonogenic capacity. PIM2 is known to be subject to ubiquitination‐independent proteasomal degradation. Consistent with this, the proteasome inhibitors bortezomib and carfilzomib increased PIM2 protein levels in MM cells without affecting its mRNA levels. However, SMI‐16a mitigated the PIM2 protein increase and cooperatively enhanced anti‐MM effects in combination with carfilzomib. Collectively, the thiazolidine‐2,4‐dione‐family compounds SMI‐16a and SMI‐4a uniquely reduce PIM2 protein in MM cells, which may contribute to their profound efficacy in addition to their immediate kinase inhibition. Their combination with proteasome inhibitors is envisioned.

Results from pilot run for MEG II positron timing counter

The MEG II experiment at Paul Scherrer Institut in Switzerland will search for the lepton flavour violating muon decay, \(\mu ^+\rightarrow e^+\gamma \), with a sensitivity of \(4\times 10^{-14}\) improving the existing limit of an order of magnitude. In 2016, we finished the construction of the MEG II Timing Counter, the subdetector dedicated to the measurement of the positron emission time. The first one-fourth of it was installed in the experimental area and we performed a pilot run with the MEG II beam of \(7\times 10^{7}\mu ^+/\)s. The timing resolution reached the design value improving by a factor of two compared to MEG.

A high resolution timing counter for the MEG II experiment

The development of a Timing Counter detector with a resolution in the range of ≈ 30 ps will be presented. The detector was designed for the upgrade of the MEG II experiment looking for the μ+ → e+γ decay with an improved sensitivity of one order of magnitude with respect to the previous MEG setup. In this paper the design of the TC single pixel is explained together with the results obtained in beam tests.

Chemoenzymatic Synthesis of α-Substituted Serines via Enantiodivergent Transformation

A series of (R)-N-Cbz-2-alkyl-2-amino-3-hydroxypropyl acetates was prepared by enzymatic acetylation of N- Cbz-2-alkyl-2-aminopropane-1,3-diols with immobilized lipoprotein lipase from Pseudomonas sp. in up to 98% enanti- omeric excess (ee). Enantiodivergent oxidation of (R)-N-Cbz-2-alkyl-2-amino-3-hydroxypropyl acetates readily furnished (R)- and (S)- -substituted serines ( -benzylserines and  -methylserines). Enzymatic hydrolysis of diethyl N-Cbz-2- amino-2-methylmalonate catalyzed by porcine liver esterase afforded (R)-N-Cbz-2-amino-3-ethoxy-2-methyl-3- oxopropanoic acid in 97% ee. (R)-N-Cbz-2-amino-3-ethoxy-2-methyl-3-oxopropanoic acid was also transformed to both enantiomers of  -methylserine via enantiodivergent reduction.