Foreword

The Pharmaceutical Society of Japan (PSJ) has projected International Symposium for Medicinal Sciences (ISMS) with pharmaceutical company researchers being encouraged to participate in the annual meeting of the PSJ and to create a close international contact with researchers interested in medicinal sciences. The 1st, 2nd, 3rd, and 4th ISMS were held in the 135th, 136th, 137th, and 138th annual meetings at Kobe, Yokohama, Sendai, and Kanazawa, respectively. The 5th ISMS, including two invited lectures by Prof. James A. Wells, University of California, San Francisco, U.S.A., and Prof. Andrew L. Hopkins, Exscientia Ltd., U.K., and 43 invited poster presentations, was organized in the 139th Chiba annual meeting in 2019. Prof. Wells presented the lecture about “Attacking the Cell Surfaceome in Cancer” and Prof. Hopkins introduced recent advances in “The AI Revolution in Drug Discovery.” And we called active contributions from invited poster precentors in the 5th ISMS. For the Current Topics section in the Chemical and Pharmaceutical Bulletin (CPB) and Biological and Pharmaceutical Bulletin (BPB), we have assembled fourteen contributions. In this issue of the CPB are published four reviews, two communications, and two regular articles which covered the entire drug discovery field including medicinal chemistry, pharmacology, pharmacokinetics, and regulatory sciences.

The first review, entitled “Potent Antibiotics Active against Multidrug-Resistant Gram-Negative Bacteria” was contributed by Dr. Otsuka of BIKAKEN. This review focuses the recent advances in the development of promising antibacterial agents, including novel tetracyclines, polymyxins, β-lactams, β-lactams/β-lactamase inhibitors, aminoglycosides, and peptide mimetics, against multidrug-resistant (MDR) Gram-negative bacteria.

The second review, “Revolution of Small Molecule Drug Discovery by Affinity Selection-Mass Spectrometry Technology” is by Dr. Motoyaji of SEEDSUPPLY INC. In this review, principles of affinity selection-mass spectrometry (AS-MS) as a label-free binding assay technology with application to high-throughput screening is presented.

“ALK2: A Therapeutic Target for Fibrodysplasia Ossificans Progressiva and Diffuse Intrinsic Pontine Glioma,” the third review by Dr. Sekimata et al. overviews the recent developments and discovery of the biological and common pathogenic roles of the bone morphogenic protein (BMP) receptor ALK2 in two pediatric diseases, fibrodysplasia ossificans progressiva (FOP), and diffuse intrinsic pontine glioma (DIPG).

The fourth review, entitled “Antibody–Drug Conjugate Payloads; Study of Auristatin Derivatives” is by Dr. Akaiwa et al. focuses the investigation of the structure–activity relationship of Auristatins derivatives as important payloads used in antibody–drug conjugates (ADCs) with the goal of applying theses to next generation ADCs.

“A Stable and Cleavable O-Linked Spacer for Drug Delivery Systems,” the first communication by Prof. Kanai and his colleagues, reports the development of a cleavable linker which is satisfying the requirements in both stability and cleavability in the application to anti-cancer chemotherapy.

The second communication, entitled “Development of a Turn-On Fluorescent Traceable Linker Employing N-Sulfanylethylcoumarinyl Amide for the Enrichment and Visualization of Target Proteins” is by Dr. Shigenaga and his colleagues. In this communication, A turn-on fluorescent traceable linker based on N-sulfanylethylcoumarinyl amide (SECmide) has been developed as an advanced cleavable linker with successful application to enrichment and selective visualization of a target protein in cell lysate.

The first original article, “Structure–Activity Relationship Study on Col-003, a Protein–Protein Interaction Inhibitor between Collagen and Hsp47,” by Prof. Doi and his colleagues, the structure–activity relationship on Col-003, a potent collagen–Hsp47 interaction inhibitor is described. The Col-003 analogs were successfully synthesized by Pd(0)-catalyzed cross-coupling reactions of 5-bromosalicylaldehyde derivatives with alkyl–metal species, and the inhibitory activities of synthetic analogs were evaluated using surface plasmon resonance analysis (BIAcore).

In “Strategies for Design of Molecular Structures with a Desired Pharmacophore Using Deep Reinforcement Learning,” the second original article by Dr. Yoshimori et al. shows that a computational strategy based on deep reinforcement learning for generating molecular structures with a desired pharmacophore. Additionally, chemical genomics-based virtual screening (CGBVS) is used to extract selective molecules against a target protein.

I believe that these reviews, communications, and articles provide useful information for progress of medicinal sciences and sincerely thank all authors for their significant contributions.