Iejimalides Show Anti-Osteoclast Activity<i>via</i>V-ATPase Inhibition

Kazami, Sayaka; Muroi, Makoto; Kawatani, Masahito; Kubota, Takaaki; Usui, Takeo; Kobayashi, Jun’ichi; Osada, Hiroyuki

doi:10.1271/bbb.50644

Cited by 40 publications

(39 citation statements)

References 30 publications

(44 reference statements)

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“…12) In brief, human cervical carcinoma HeLa cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% (v/v) fetal calf serum (FCS) in a humidified atmosphere containing 5% CO 2 . Cells were seeded onto coverslips and incubated for 2 h with latrunculin A, bafilomycin A 1 or compounds 2 or 3 at the indicated concentrations.…”

Section: Methodsmentioning

confidence: 99%

“…Cell 12) were inoculated into 5 mL of 0.5% agar containing 0.004% sodium dodecyl sulfate (SDS) (cooled to 45°C), and the cell suspension was spread on the surface of prewarmed YPDA plates (1% yeast extract, 2% polypeptone, 2% glucose, 0.02% adenine, 1.5% agar). One micro liter of drug solutions were spotted on a plate containing each strain and the plates were cultured at 30°C for 2 d, and clear zones around the spots were photographed.…”

Section: Methodsmentioning

confidence: 99%

“…Further investigation revealed that the molecular target of IEJL-A and -B is V-ATPase and that IEJLs-A and -B show antiosteoporotic activity via V-ATPase inhibition. 12) Recently, Fürstner et al reported the total synthesis of IEJL-B 13) and IEJLs-A-D, 13) and their investigation of the biological activity of IEJL-B and its non-natural analogues was focused on the actin cytoskeleton. They found that IEJL-B induced severe changes of the actin cytoskeleton in NIH/3T3 cells.…”

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confidence: 99%

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Iejimalide C Is a Potent V-ATPase Inhibitor, and Induces Actin Disorganization

Kazami

Takaine

Itoh

et al. 2014

Biological & Pharmaceutical Bulletin

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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). However IEJL-C and -D, which are sulfonylated IEJL-A and -B, respectively, show more potent antitumor activity, and their molecular targets remain to be discovered. Here, we report that IEJL-C is also a potent V-ATPase inhibitor by binding in a site similar to the bafilomycin-binding site. Two-hour treatment with IEJL-C resulted in the complete disappearance of acidic organelles in HeLa cells. Interestingly, after 24-h treatment, small actin aggregates were observed instead of actin fibers. The same actin reorganization was also observed in cells treated with another V-ATPase inhibitor, bafilomycin A 1 . Because IEJLs did not inhibit actin polymerization in vitro, these results suggest that the primary target of IEJL-C, as well as IEJL-A and -B, is V-ATPase, and actin reorganizations are probably caused by the disruption of pH homeostasis via V-ATPase inhibition.Key words antitumor; cytotoxicity; iejimalide C; V-ATPase; actin cytoskeleton V-ATPases are among the most widely distributed ATPdriven proton pumps in nature, present in all eukaryotic cells and in various bacteria.1,2) Within eukaryotic cells, the structure of these proton pumps is highly conserved from yeast to humans, as a multiple subunit complex with a molecular mass exceeding 850 kDa. The pumps contain at least 13 different subunits with various copy numbers, which are organized into two distinct domains, a peripheral V 1 domain that is the catalytic sector and a transmembrane V 0 domain that constitutes the proton channel. Recently, it has been reported that VATPases are expressed in the plasma membrane of malignant and metastatic tumor cells, and function in the maintenance of intracellular pH.3) Furthermore, it has been found that VATPases are attractive therapeutic targets of tumor cells in vitro 4) and in vivo. 5) These reports strongly suggest that VATPase inhibitors are good candidates for anticancer agents. The mechanism by which such inhibitors interfere with pump function has been investigated in detail. The most potent inhibitors, bafilomycin A 1 6) and the closely related compound concanamycin A, inhibit V-ATPases at nanomolar concentrations and have become important tools for the detection and identification of V-ATPase activity. The site of bafilomycin inhibition has been located to subunit c in the V 0 proton channel. 7,8) Iejimalides (IEJLs) A-D, isolated from the marine tunicate Eudistoma cf. rigida, are unique 24-membered macrolides having two methoxy groups, four diene units, and an N-formyl-L-serine terminus 9,10) ( Fig. 1). Because these compounds exhibit potent cytotoxic activity in vitro and antitumor activity in vivo, 11) their target molecules and antitumor mechanisms have been attractive subjects for investigation. During the screening of novel...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Iejimalide C Is a Potent V-ATPase Inhibitor, and Induces Actin Disorganization

Kazami

Takaine

Itoh

et al. 2014

Biological & Pharmaceutical Bulletin

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“…Elucidation of the mechanisms underlying bisphosphonate activity, especially the identification of target proteins, has led to a deep understanding of osteoclast function (4). In addition, many naturally occurring small molecules have been reported to inhibit the differentiation and function of osteoclasts (5)(6)(7)(8)(9)(10)(11)(12).…”

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confidence: 99%

“…Cellular phenotype-based assays can be used to identify osteoclast-targeting small-molecule inhibitors (9). After cellular phenotype-based assays, the target identification of bioactive small molecules is one of the most important steps.…”

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confidence: 99%

The identification of an osteoclastogenesis inhibitor through the inhibition of glyoxalase I

Kawatani

Okumura

Honda

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Osteoclasts, bone-resorptive multinucleated cells derived from hematopoietic stem cells, are associated with many bone-related diseases, such as osteoporosis. Osteoclast-targeting small-molecule inhibitors are valuable tools for studying osteoclast biology and for developing antiresorptive agents. Here, we have discovered that methyl-gerfelin (M-GFN), the methyl ester of the natural product gerfelin, suppresses osteoclastogenesis. By using M-GFNimmobilized beads, glyoxalase I (GLO1) was identified as an M-GFN-binding protein. GLO1 knockdown and treatment with an established GLO1 inhibitor in osteoclast progenitor cells interfered with osteoclast generation, suggesting that GLO1 activity is required for osteoclastogenesis. In cells, GLO1 plays a critical role in the detoxification of 2-oxoaldehydes, such as methylglyoxal. M-GFN inhibited the enzymatic activity of GLO1 in vitro and in situ. Furthermore, the cocrystal structure of the GLO1/M-GFN complex revealed the binding mode of M-GFN at the active site of GLO1. These results suggest that M-GFN targets GLO1, resulting in the inhibition of osteoclastogenesis.osteoclast ͉ small molecule ͉ crystal structure

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Modification of Bafilomycin Structure to Efficiently Synthesize Solid‐State NMR Probes that Selectively Bind to Vacuolar‐Type ATPase

Shibata

Tsuchikawa

Hayashi

et al. 2015

Chemistry An Asian Journal

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Bafilomycin (Baf) is one of the most potent inhibitors of vacuolar-type ATPase, which is strongly implicated in age-related diseases. However, the binding site of the antibiotic on the protein remains unclear because of the complexity of the structure of Baf bound to the target subunit in the transmembrane region. For conducting structural studies by applying solid-state NMR, which is one of the most promising methodologies available for structural analysis in membrane system, preparing bioactive fluorinated Baf analogues is essential. In this study two Baf analogues were carefully designed and efficiently synthesized through the convergent coupling of three segments. Biological evaluation revealed that the activity of 24-F-Baf was comparable to that of Baf, indicating its utility as a potential probe for solid-state NMR analysis. By contrast, desmethylated 24-F-Baf exhibited markedly diminished activity. The absence of two methyl groups caused a critical conformational change in the macrocyclic core structure necessary for binding to the target protein.

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Iejimalides Show Anti-Osteoclast ActivityviaV-ATPase Inhibition

Cited by 40 publications

References 30 publications

Iejimalide C Is a Potent V-ATPase Inhibitor, and Induces Actin Disorganization

Iejimalide C Is a Potent V-ATPase Inhibitor, and Induces Actin Disorganization

The identification of an osteoclastogenesis inhibitor through the inhibition of glyoxalase I

Modification of Bafilomycin Structure to Efficiently Synthesize Solid‐State NMR Probes that Selectively Bind to Vacuolar‐Type ATPase

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