Takashi Futami

Deregulation of pancreas-specific oxidoreductin ERO1β in the pathogenesis of diabetes mellitus

ABSTRACT A growing body of evidence has underlined the significance of endoplasmic reticulum (ER) stress in the pathogenesis of diabetes mellitus. ER oxidoreductin 1β (ERO1β) is a pancreas-specific disulfide oxidase that is known to be upregulated in response to ER stress and to promote protein folding in pancreatic β cells. It has recently been demonstrated that ERO1β promotes insulin biogenesis in β cells and thus contributes to physiological glucose homeostasis, though it is unknown if ERO1β is involved in the pathogenesis of diabetes mellitus. Here we show that in diabetic model mice, ERO1β expression is paradoxically decreased in β cells despite the indications of increased ER stress. However, overexpression of ERO1β in β cells led to the upregulation of unfolded protein response genes and markedly enlarged ER lumens, indicating that ERO1β overexpression caused ER stress in the β cells. Insulin contents were decreased in the β cells that overexpressed ERO1β, leading to impaired insulin secretion in response to glucose stimulation. These data indicate the importance of the fine-tuning of the ER redox state, the disturbance of which would compromise the function of β cells in insulin synthesis and thus contribute to the pathogenesis of diabetes mellitus.

ASP5878, a Novel Inhibitor of FGFR1, 2, 3, and 4, Inhibits the Growth of FGF19-Expressing Hepatocellular Carcinoma

Hepatocellular carcinoma is an aggressive cancer with poor prognosis. Fibroblast growth factor 19, a member of the fibroblast growth factor family, is a ligand for fibroblast growth factor receptor 4. Moreover, it plays a crucial role in the progression of hepatocellular carcinoma. ASP5878 is a novel inhibitor of fibroblast growth factor receptors 1, 2, 3, and 4 that is under development. It inhibits fibroblast growth factor receptor 4 kinase activity with an IC50 of 3.5 nmol/L. ASP5878 potently suppressed the growth of the fibroblast growth factor 19–expressing hepatocellular carcinoma cell lines Hep3B2.1-7, HuH-7, and JHH-7. In the Hep3B2.1-7 cell line, ASP5878 inhibited the phosphorylation of fibroblast growth factor receptor 4 and its downstream signaling molecules as well as induced apoptosis. Oral administration of ASP5878 at 3 mg/kg induced sustained tumor regression in a subcutaneous xenograft mouse model using Hep3B2.1-7. In HuH-7, an orthotopic xenograft mouse model, ASP5878 induced complete tumor regression and dramatically extended the survival of the mice. These results suggest that ASP5878 is a potentially effective therapeutic agent for hepatocellular carcinoma patients with tumors expressing fibroblast growth factor 19. Mol Cancer Ther; 16(1); 68–75. ©2016 AACR.

Abstract A172: Preclinical antitumor activity of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, in FGF19-expressing hepatocellular carcinoma

Background: Fibroblast growth factor (FGF) / FGF receptor (FGFR) gene aberrations such as amplification, mutation and fusion are associated with many types of human cancers. Recently, FGF19 overexpression was observed in approximately 50% of hepatocellular carcinoma (HCC) patients. The FGF19-FGFR4 signaling has been implicated in the development of HCCs in mice. FGFR4 kinase inhibitors are expected to be a targeted therapy for FGF19-expressing HCC. A phase I clinical trial of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, is ongoing (NCT02038673). Method: We tested selectivity of ASP5878 among 128 kinases and sensitivity of ASP5878 on cell proliferation of HCC cell lines. Activation of FRS2 and ERK, downstream molecules of FGFR signaling, and PARP cleavage in FGF19 expressing HCC cell lines were evaluated with Western blotting. In vivo antitumor effects of ASP5878 were examined in HCC subcutaneous xenograft and orthotopic inoculation mouse models. Finally, plasma levels of FGF19 were measured after dosing ASP5878. Results: Among 128 kinases, only 9 kinases including FGFR1-4 and FGFR3/4 mutations were inhibited more than 50% by ASP5878 (200 nmol/L). The IC50 values of ASP5878 against FGFR1, 2, 3 and 4 kinases were 0.47, 0.60, 0.74 and 3.5 nmol/L, respectively. ASP5878 inhibited cell proliferation of HCC cell lines with FGF19 overexpression. IC50 values were 8.5, 27, and 21 nmol/L in Hep3B2.1-7, HuH-7 and JHH-7, respectively. ASP5878 inhibited activation of downstream signaling molecules, FRS2 and ERK, and induced apoptosis in Hep3B2.1-7 cells. Oral dosing of ASP5878 at 3 mg/kg induced sustained tumor regression in the Hep3B2.1-7 subcutaneous xenograft model, which was poorly responsive to sorafenib. In an HuH-7 orthotopic inoculation mouse model, ASP5878 induced complete tumor regression and dramatically extended the survival. In addition, oral dosing of ASP5878 reduced plasma levels of FGF19 in the HuH-7 subcutaneous xenograft model.Conclusion: These results suggest that ASP5878 is a potentially effective therapeutic agent for FGF19-expressing HCC. Citation Format: Takashi Futami, Hidetsugu Okada, Rumi Kihara, Tatsuya Kawase, Ayako Nakayama, Tomoyuki Suzuki, Minoru Kameda, Nobuaki Shindoh, Tadashi Terasaka, Masaaki Hirano, Sadao Kuromitsu. Preclinical antitumor activity of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, in FGF19-expressing hepatocellular carcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A172.