Kazuki Miyazaki

Lenvatinib, an angiogenesis inhibitor targeting VEGFR/FGFR, shows broad antitumor activity in human tumor xenograft models associated with microvessel density and pericyte coverage

BackgroundLenvatinib is an oral inhibitor of multiple receptor tyrosine kinases (RTKs) targeting vascular endothelial growth factor receptor (VEGFR1-3), fibroblast growth factor receptor (FGFR1-4), platelet growth factor receptor α (PDGFR α), RET and KIT. Antiangiogenesis activity of lenvatinib in VEGF- and FGF-driven angiogenesis models in both in vitro and in vivo was determined. Roles of tumor vasculature (microvessel density (MVD) and pericyte coverage) as biomarkers for lenvatinib were also examined in this study.MethodWe evaluated antiangiogenesis activity of lenvatinib against VEGF- and FGF-driven proliferation and tube formation of HUVECs in vitro. Effects of lenvatinib on in vivo angiogenesis, which was enhanced by overexpressed VEGF or FGF in human pancreatic cancer KP-1 cells, were examined in the mouse dorsal air sac assay. We determined antitumor activity of lenvatinib in a broad panel of human tumor xenograft models to test if vascular score, which consisted of high MVD and low pericyte coverage, was associated with sensitivity to lenvatinib treatment. Vascular score was also analyzed using human tumor specimens with 18 different types of human primary tumors.ResultLenvatinib inhibited VEGF- and FGF-driven proliferation and tube formation of HUVECs in vitro. In vivo angiogenesis induced by overexpressed VEGF (KP-1/VEGF transfectants) or FGF (KP-1/FGF transfectants) was significantly suppressed with oral treatments of lenvatinib. Lenvatinib showed significant antitumor activity in KP-1/VEGF and five 5 of 7 different types of human tumor xenograft models at between 1 to 100 mg/kg. We divided 19 human tumor xenograft models into lenvatinib-sensitive (tumor-shrinkage) and relatively resistant (slow-growth) subgroups based on sensitivity to lenvatinib treatments at 100 mg/kg. IHC analysis showed that vascular score was significantly higher in sensitive subgroup than relatively resistant subgroup (p < 0.0004). Among 18 types of human primary tumors, kidney cancer had the highest MVD, while liver cancer had the lowest pericyte coverage, and cancers in Kidney and Stomach had highest vascular score.ConclusionThese results indicated that Lenvatinib inhibited VEGF- and FGF-driven angiogenesis and showed a broad spectrum of antitumor activity with a wide therapeutic window. MVD and pericyte-coverage of tumor vasculature might be biomarkers and suggest cases that would respond for lenvatinib therapy.

Antipruritic effect of the topical phosphodiesterase 4 inhibitor E6005 ameliorates skin lesions in a mouse atopic dermatitis model.

Phosphodiesterase (PDE) 4 inhibition is a well-known anti-inflammatory mechanism, but the development of PDE4 inhibitors has been hampered by side effects such as nausea and emesis. Local delivery of a PDE4 inhibitor to the site of inflammation may overcome these issues. The purpose of this study was to assess the therapeutic potential of E6005 (methyl 4-[({3-[6,7-dimethoxy-2-(methylamino)quinazolin-4-yl]phenyl}amino)carbonyl]benzoate), a novel PDE4 inhibitor developed as a topical agent for atopic dermatitis (AD). E6005 potently and selectively inhibited human PDE4 activity with an IC50 of 2.8 nM and suppressed the production of various cytokines from human lymphocytes and monocytes with IC50 values ranging from 0.49 to 3.1 nM. In mice models, the topical application of E6005 produced an immediate antipruritic effect as well as an anti-inflammatory effect with reduced expression of cytokines/adhesion molecules. On the basis of these observed effects, topical E6005 ameliorated the appearance of atopic dermatitis-like skin lesions in two types of AD models, hapten- and mite-elicited models, exhibiting inhibitory effects comparable to that of tacrolimus. The use of 14C-labeled E6005 showed rapid clearance from the blood and low distribution to the brain, contributing to the low emetic potential of this compound. These results suggest that E6005 may be a promising novel therapeutic agent with antipruritic activity for the treatment of AD.

Microregional antitumor activity of a small-molecule hypoxia-inducible factor 1 inhibitor.

Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes that play crucial roles in the adaptation of cancer cells to hypoxia. HIF-1α overexpression has been associated with poor prognosis in patients with various types of cancer. Here, we describe ER-400583-00 as a novel HIF-1 inhibitor. ER-400583-00 suppressed the production of HIF-1α protein in response to hypoxia, with a half-maximal inhibitory concentration value of 3.7 nM in human U251 glioma cells. The oral administration of 100 mg/kg ER-400583-00 to mice bearing U251 tumor xenografts resulted in a rapid suppression of HIF-1α that persisted for 24 h. Immunohistochemical analysis revealed that ER-400583-00 suppressed the proliferation of cancer cells most prominently in areas distal to the region of blood perfusion, where HIF-1α-expressing hypoxic cancer cells were located. These hypoxic cancer cells were resistant to radiation therapy. ER-400583-00 showed a synergistic interaction with radiation therapy in terms of antitumor activity. These data suggest that HIF-1 blockade by small compounds may have therapeutic value in cancer, especially in combination with radiation therapy.

Synthesis and structure-activity relationships of novel, potent, orally active hypoxia-inducible factor-1 inhibitors.

Hypoxia-inducible factor-1 (HIF-1) is the chief transcription factor regulating hypoxia-driven gene expression. HIF-1 overexpression is associated with poor prognosis in several cancers and therefore represents an attractive target for novel antitumor agents. We explored small molecule inhibitors of the HIF-1 pathway. Using high-throughput-screening, we identified benzanilide compound 1 (IC50=560 nM) as a seed. Subsequent extensive derivatization led to the discovery of compounds 43a and 51d, with anti-HIF-1 activities in vitro (IC50=21 and 0.47 nM, respectively), and in vivo. Additionally, 43a (12.5-100mg/kg) also displayed in vivo anti-tumor efficacy, without influencing body weight.

Application of phosphodiesterase 4 inhibitor for atopic dermatitis.

キーワード:アトピー性皮膚炎,痒み,phosphodiesterase 4,E6005 エーザイ株式会社 筑波研究所(〒300 -2635 茨城県つくば市東光台 5 -1 -3) E-mail: n3 ishii@hhc.eisai.co.jp 原稿受領日:2014 年 7 月 2 日,依頼原稿 Title: Application of phosphodiesterase 4 inhibitor for atopic dermatitis Author: Naoto Ishii, Hisatsugu Wakita, Kazuki Miyazaki, Yasutaka Takase, Osamu Asano, Kazutomi Kusano, Manabu Shirato 要約:日本皮膚科学会によるとアトピー性皮膚炎 (AD)の定義は「増悪と寛解を繰り返す,痒みを伴う 湿疹を主病変とする慢性に経過する疾患」とされてお り,今なお患者数が増大する傾向にある.ADでは重 度な痒みを伴うことが特徴であり,既存薬では十分な 痒み抑制作用が得られているとは言えず,痒みのコン トロールが治療の課題の一つと考えられている.そこ で改めて AD病態を振り返り,治療薬開発の現状を纏 めた.その中で phosphodiesterase 4(PDE4)阻害薬 に注目し,E6005 を題材として PDE4 阻害薬の AD適 応を目指した取り組みを紹介する.E6005 は無細胞 PDE活性測定系において選択的な PDE4 阻害作用を 示し,ヒト末梢血リンパ球・単球からのサイトカイン 産生を抑制したことから,PDE4 阻害に基づく E6005 の抗炎症作用を確認できた.ハプテン誘発接触皮膚炎 型マウスモデルにおいて,E6005 を連続塗布すると有 意な皮膚炎抑制効果が得られ,かつ皮疹部におけるサ イトカイン・接着分子の発現抑制効果が認められた. さらに ADマウスモデルである NC/Ngaマウスに E6005 を連続塗布すると AD様皮膚炎抑制効果が得ら れたほか,単回塗布による即時的な掻破行動抑制効果 も認められた.PDE4 阻害作用に基づく嘔吐誘発に関 してキシラジン・ケタミン麻酔覚醒モデルを用いて検 討したところ,E6005 は第一世代 PDE4 阻害薬シロミ ラストと比較して嘔吐誘発性が低いことが分かり,治 療濃度域の広さが認められた.E6005 は血液中で速や かに代謝され,中枢神経系への分布が非常に少ないこ とから嘔吐誘発性の低下に繋がった可能性がある.こ れらの結果より,E6005 は全身的暴露を最小限に抑え た局所投与型薬剤として,抗炎症作用のみならず痒み 抑制作用を併せ持つアトピー性皮膚炎治療薬として期 待される.