BCPP compounds, PET probes for early therapeutic evaluations, specifically bind to mitochondrial complex I.

BCPP compounds have been developed as PET imaging probes for neurodegenerative diseases in the living brain. F-BCPP-EF identifies damaged neuronal areas based on the lack of MC-I; however, its underlying mechanisms of action and specificity for MC-I remain unclear. We herein report the effects of BCPP-BF, -EF, -EM on MC-I in respiratory chain complexes using cardiomyocyte SMP.

Vicenistatin induces early endosome-derived vacuole formation in mammalian cells.

Homotypic fusion of early endosomes is important for efficient protein trafficking and sorting. The key controller of this process is Rab5 which regulates several effectors and PtdInsPs levels, but whose mechanisms are largely unknown. Here, we report that vicenistatin, a natural product, enhanced homotypic fusion of early endosomes and induced the formation of large vacuole-like structures in mammalian cells.

Iejimalide C is a potent V-ATPase inhibitor, and induces actin disorganization.

Iejimalides (IEJLs) A-D are 24-membered macrolides isolated from a tunicate Eudistoma cf. rigida, and exhibit potent cytotoxicity in vitro and antitumor activity in vivo. We previously reported that the molecular target of IEJL-A and -B was the vacuolar-type H(+)-ATPases (V-ATPases).

Glaziovianin A prevents endosome maturation via inhibiting microtubule dynamics.

Glaziovianin A, an isoflavone isolated from the leaves of Ateleia glazioviana, inhibits the cell cycle progression in M-phase with an abnormal spindle structure, but its inhibitory mechanism has not been revealed. Here, we report that glaziovianin A and its derivatives are microtubule dynamics inhibitors. Glaziovianin A extended the time lag of tubulin polymerization without changing the net amount of polymerized tubulin in vitro and suppressed microtubule dynamics in cells.

Morphobase, an encyclopedic cell morphology database, and its use for drug target identification.

Visual observation is a powerful approach for screening bioactive compounds that can facilitate the discovery of attractive druggable targets following their chemicobiological validation. So far, many high-content approaches, using sophisticated imaging technology and bioinformatics, have been developed. In our study, we aimed to develop a simpler method that focuses on intact cell images because we found that dynamic changes in morphology are informative, often reflecting the mechanism of action of a drug.

Actin stress fiber retraction and aggresome formation is a common cellular response to actin toxins.

F-actin-stabilizing drugs induce actin aggresome formation. In this study, we found that an actin-depolymerizing drug, latrunculin A (LatA), induced actin aggresomes. Actin stress fibers were retracted and disappeared in minutes, but a large aggresome formed in consequence of LatA treatment.

Structure-activity relationship study of glaziovianin A against cell cycle progression and spindle formation of HeLa S3 cells.

Various derivatives of glaziovianin A, an antitumor isoflavone, were synthesized, and the cytotoxicity of each against HeLa S3 cells was investigated. Compared to glaziovianin A, the O7-allyl derivative was found to be more cytotoxic against HeLa S3 cells and a more potent M-phase inhibitor.

Application of proteomic profiling based on 2D-DIGE for classification of compounds according to the mechanism of action.

The development of new anticancer agents derived from natural resources requires a rapid identification of their molecular mechanism of action. To make this step short, we have initiated the proteomic profiling of HeLa cells treated with anticancer drugs representing a wide spectrum of mechanisms of action using two-dimensional difference gel electrophoresis (2D-DIGE). Unique proteome patterns were observed in HeLa cells treated with the HSP90 inhibitor geldanamycin, and were similar to the patterns induced by radicicol, a structurally different HSP90 inhibitor.

Glaziovianin A, a new isoflavone, from the leaves of Ateleia glazioviana and its cytotoxic activity against human cancer cells.

A new isoflavone, named glaziovianin A (1), was isolated from the leaves of Ateleia glazioviana (Legminosae) by means of a cytotoxicity-guided fractionation procedure against HL-60 leukemia cells. The chemical structure of 1 was determined by analysis of its extensive spectroscopic data. Glaziovianin A (1) displayed differential cytotoxicities in the Japanese Foundation for Cancer Research 39 cell line panel assay.

Iejimalides show anti-osteoclast activity via V-ATPase inhibition.

Iejimalides (IEJLs), 24-membered macrolides, are potent antitumor compounds, but their molecular targets remain to be revealed. In the course of screening, we identified IEJLs as potent osteoclast inhibitors. Since it is known that osteoclasts are sensitive to vacuolar H(+)-ATPase (V-ATPase) inhibitor, we investigated the effect of IEJLs on V-ATPases.

Amphidinolide h, a potent cytotoxic macrolide, covalently binds on actin subdomain 4 and stabilizes actin filament.

The actin-targeting toxins have not only proven to be invaluable tools in studies of actin cytoskeleton structure and function but they also served as a foundation for a new class of anticancer drugs. Here, we describe that amphidinolide H (AmpH) targets actin cytoskeleton. AmpH induced multinucleated cells by disrupting actin organization in the cells, and the hyperpolymerization of purified actin into filaments of apparently normal morphology in vitro.