A new antimitotic substance, FR182877. III. Structure determination.

During the course of screening for novel cell cycle inhibitors, FR182877 was isolated from the fermentation broth of Streptomyces sp. No.9885. During the NMR measurements, FR182877 decomposed so much that the structure elucidation of FR182877 itself was difficult. Then, combinations of chemical correlations and spectroscopic methods clarified that FR182877 possesses an unprecedented multi-ring system including the strained double bond, which was unexpectedly epoxidized by molecular oxygen. FR182877 showed broad antitumor activities in vitro and promoted assemblies of tublins in vitro as well as taxol. It is noteworthy that epoxidation of the distorted double bond resulted in significant decrease in antitumor activities.

A new antimitotic substance, FR182877. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

Using the characteristic morphological changes of mammalian cells, we screened novel antimitotic substances and found that a strain of Streptomyces sp. No.9885 produced FR182877. This substance was isolated from the culture broth by ethyl acetate extraction, silica gel column chromatography and ODS column chromatography. Structural studies on FR182877 suggested that it had a unique hexacyclic structure encompassing its highly strained double bond. FR182877 exhibited potent antitumor activities against murine ascitic tumor and solid tumor in vivo.

[Inhibition of corneal neovascularization--the possibility of inhibition by drug administration].

PURPOSE: The anti-angiogenic activity of FR 118487, a new synthetic analog of Scolecobasidium arenarium products, was examined in Japanese white rabbit cornea. METHODS: We studied both systemic and locally administered FR 118487 (ointment) in a keratoplasty model consisting of corneal neovascularization after implantation of a Wister rat cornea into a rabbit cornea. RESULTS: Two weeks after the implantation, the maximum length of neovascularization was 3.4 +/- 0.3 mm in control corneas, 0.1 +/- 0.0 mm with systemic FR 118487 administration (10 mg/day) (p < 0.01), 0.1 +/- 0.1 mm with 10% FR118487 ointment (p < 0.001), 1.0 +/- 0.2 mm with 3% FR 118487 ointment (p < 0.001), and 0.9 +/- 0.9 mm with 1% FR 118487 ointment (p < 0.02). CONCLUSION: FR 118487 had a significant effect on inhibition of corneal neovascularization.

FR901228, a potent antitumor antibiotic, is a novel histone deacetylase inhibitor.

Screening for microbial metabolites that induce transcriptional activation of the SV40 promoter resulted in the identification of two known compounds, FR901228 and trichostatin A (TSA). FR901228 is a potent antitumor drug that is currently under clinical investigation. TSA is a specific inhibitor of histone deacetylase. Despite structural unrelatedness, both FR901228 and TSA greatly enhanced the transcriptional activity of the SV40 promoter in an enhancer-dependent manner. The effects of FR901228 on the cell cycle, chromatin structure, and histone acetylation were examined and compared with those of TSA. Both compounds caused arrest of the cell cycle at both G1 and G2/M phases and induction of internucleosomal breakdown of chromatin. FR901228, like TSA, inhibited intracellular histone deacetylase activity, as a result of which marked amounts of acetylated histone species accumulated. FR901228 is therefore a new type of histone deacetylase inhibitor, whose chemical structure is unrelated to known inhibitors such as trichostatins and trapoxins.

[Inhibition of corneal neovascularization by a new analog of fungal product].

The anti-angiogenic activity if FR 118487, a new synthetic analogue of Scolecobasidium arenarium products, was examined in corneas of Japanese white rabbits. We studied locally administered FR 118487 with hydron pellets in two models; corneal neovascularization after implantation of a CuCl2 pellet (CuCl2-induced model) and a Wistar rat's cornea (keratoplasty model) into a rabbit cornea. In the CuCl2-induced model, maximum length of neovascularization was 0.08 +/- 0.10 (mean +/- standard deviation) mm with FR 118487 (control 2.84 +/- 0.13 mm) at 1 week after the implantation. In the keratoplasty model, maximum length of neovascularization was 0.05 +/- 0.05 mm with FR 118487 (control 3.33 +/- 0.18 mm) at 2 weeks after the implantation. In both models, FR 118487 had a significant (p < 0.01) effect on inhibition of corneal neovascularization.

New antitumor substances, FR901463, FR901464 and FR901465. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

New antitumor substances, FR901463, FR901464 and FR901465 were isolated from the culture broth of a bacterium of Pseudomonas sp. No.2663. FR901463, FR901464 and FR901465 remarkably enhanced the transcriptional activity of the promoter of SV40 DNA virus. Further, these compounds exhibited potent antitumor activities against murine and human tumor cell lines in vitro.

New antitumor substances, FR901463, FR901464 and FR901465. II. Activities against experimental tumors in mice and mechanism of action.

FR901463, FR901464 and FR901465, novel antitumor substances, were isolated from the fermentation broth of Pseudomonas sp. No. 2663. Their antitumor activities were examined in three mouse tumor systems and one human tumor system. The three FR compounds prolonged the life of mice bearing murine ascitic tumor P388 leukemia (T/C values were 160%, 145% and 127% for FR901463, FR901464 and FR901465, respectively), and inhibited the growth of a human solid tumor, A549 lung adenocarcinoma, with different effective dose ranges. FR901464 exhibited most prominent effects on these tumor systems among the three FR compounds. FR901464 also inhibited the growth of murine solid tumors, Colon 38 carcinoma and Meth A fibrosarcoma. To address the involvement of transcriptional activation ability of the three FR compounds in the antitumor effect, we selected FR901464 as a candidate compound and investigated cell cycle transition, chromatin status and endogenous gene expression in FR901464-treated tumor cells having elevated transcriptional activity. FR901464 induced characteristic G1 and G2/M phase arrest in the cell cycle and internucleosomal degradation of genomic DNA with the same kinetics as activation of SV40 promoter-dependent cellular transcription in M-8 tumor cells. In contrast to the potent activation of the viral promoter, FR901464 suppressed the transcription of some inducible endogenous genes but not house keeping genes in M-8 cells. These results suggest that FR901464 may induce a dynamic change of chromatin structure, giving rise to strong antitumor activity, and therefore may represent a new type of drug for cancer chemotherapy.

Inhibition of growth and metastasis of ovarian carcinoma by administering a drug capable of interfering with vascular endothelial growth factor activity.

The present study investigates the relationship between in vivo growth/metastasis of tumor cells and their capacity to produce the vascular endothelial growth factor (VEGF), as well as the regulation of tumor growth/metastasis using an angiogenesis-inhibitory drug. Two cloned tumor cell lines designated OV-LM and OV-HM were isolated from a murine ovarian carcinoma OV2944. OV-LM and OV-HM cells grew in cultures at comparable rates. However, when transplanted s.c. into syngeneic mice, OV-HM exhibited a faster growth rate and a much higher incidence of metastasis to lymph nodes and lung. Histologically, intense neovascularization was detected in sections of OV-HM but not of OV-LM tumor. OV-HM and OV-LM tumor cells obtained from in vitro cultures expressed high and low levels of VEGF mRNA, respectively. A difference in VEGF mRNA expression was much more clearly observed between RNAs prepared from fresh OV-HM and OV-LM tumor masses: RNA from OV-HM contained larger amounts of VEGF mRNA, whereas RNA from OV-LM exhibited only marginal levels of VEGF mRNA. An angiogenesis-inhibitory drug, FR118487 inhibited the VEGF-mediated in vitro growth of endothelial cells but did not affect the expression in vitro of VEGF mRNA by OV-HM tumor cells. Intraperitoneal injections of FR118487 into mice bearing OV-HM tumors resulted in: (i) a subsequent growth inhibition of primary tumors; (ii) a marked decrease in neovascularization inside tumor masses expressing comparable levels of VEGF mRNA to those detected in control OV-HM masses; and (iii) almost complete inhibition of metastasis to lymph nodes and lung. These results indicate that growth/metastasis of tumor cells correlates with their VEGF-producing capacity and that an angiogenesis inhibitor, FR118487, inhibits tumor growth and metastasis through mechanism(s) including the suppression of VEGF function in vivo.

A new aromatase inhibitor, FR901537. I. Taxonomy, fermentation, isolation, physiochemical characteristics and biological activities.

FR901537 is a new aromatase inhibitor produced by a bacterium Bacillus sp. No. 3072. Structural studies of FR901537 suggested that it was a novel naphthol derivative having pantetheine in its structure. FR901537 showed a potent inhibitory activity against aromatase from human placenta or rat ovary, but did not inhibit the activity of 11 beta-hydroxylase from bovine adrenal cortex. Lineweaver-Burk plot analysis revealed that FR901537 is a competitive inhibitor.

A new angiogenesis inhibitor, FR-111142.

FR-111142 is a new angiogenesis inhibitor produced by a fungus Scolecobasidium arenarium F-2015. FR-111142 inhibited endothelial cell proliferation in vitro and angiogenesis in the growing chick chorioallantoic membrane model in vivo. Further, FR-111142 also suppressed the solid tumor growth in mice.

Structure and synthesis of nectrisine, a new immunomodulator isolated from a fungus.

The structure of a novel immunomodulator, nectrisine (1), has been elucidated on the basis of chemical and spectroscopic evidence. Its absolute stereochemistry was predicted on the basis of the dibenzoate chirality rule and finally confirmed by a synthesis from D-glucose.

A new immunomodulator, FR-901235.

FR-901235 is a new type of immunoactive substance produced by an imperfect fungus, Paecilomyces carneus F-4882. The mitogen-induced lymphocyte proliferation which had been suppressed by addition of immunosuppressive factor, was restored to a normal level by the addition of FR-901235. Furthermore, the subsequent administration of FR-901235 partially restored the impaired delayed-type hypersensitivity to sheep red blood cells in tumor-bearing mice.

New antitumor antibiotic, FR-900462. I. Taxonomy of the producing strain.

A new species of the genus Streptomyces, the proposed name of which is Streptomyces tokashikiensis sp. nov., is described. Soil isolate, strain No. 7124, produces a new antitumor antibiotic FR-900462. The organism is characterized by the presence of spores on the substrate hyphae. Strain No. 7124 is closely related to Streptomyces spiralis in morphological and cultural characteristics, but there are differences in spore surface, growth-permissible temperature, and carbohydrate utilization pattern. Therefore, it was decided to designate strain No. 7124 as a new species within the genus Streptomyces.

New antitumor antibiotic, FR-900462. II. Production, isolation, characterization and biological activity.

FR-900462 is a new antitumor antibiotic produced by Streptomyces tokashikiensis No. 7124. It was highly active against leukemia P388 and melanoma B16. Furthermore, it has weak antimicrobial activity against some Gram-positive bacteria.

A new immunomodulator, FR-900490.

FR-900490 is a new type of immunoactive substance produced by a fungus Discosia sp. F-11809. The colony forming units in culture (cfu-c) in bone marrow cells, which were suppressed by immunosuppressive factor obtained from the serum of sarcoma 180 tumor bearing mouse, was restored to normal level by the addition of FR-900490 in vitro. Furthermore, in mitomycin C (MMC)-treated mice the subsequent administration of FR-900490 caused a significant increase of cfu-c in bone marrow cells depressed by MMC.