Dll4-Fc, an Inhibitor of Dll4-Notch Signaling, Suppresses Liver Metastasis of Small Cell Lung Cancer Cells through the Downregulation of the NF-κB Activity

Abstract

Notch signaling regulates cell-fate decisions during development and postnatal life. Little is known, however, about the role of Delta-like-4 (Dll4)-Notch signaling between cancer cells, or how this signaling affects cancer metastasis. We, therefore, assessed the role of Dll4-Notch signaling in cancer metastasis. We generated a soluble Dll4 fused to the IgG1 constant region (Dll4-Fc) that acts as a blocker of Dll4-Notch signaling and introduced it into human small cell lung cancer (SCLC) cell lines expressing either high levels (SBC-3 and H1048) or low levels (SBC-5) of Dll4. The effects of Dll4-Fc on metastasis of SCLC were evaluated using a mouse model. Although Dll4-Fc had no effect on the liver metastasis of SBC-5, the number of liver metastasis inoculated with SBC-3 and H1048 cells expressing Dll4-Fc was significantly lower than that injected with control cells. To study the molecular mechanisms of the effects of Dll4-Fc on liver metastasis, a PCR array analysis was conducted. Because the expression of NF-kB target genes was affected by Dll4-Fc, we conducted an electrophoretic mobility shift assay and observed that NF-kB activities, both with and without stimulation by TNF-a, were downregulated in Dll4-Fc-overexpressing SBC-3 and H1048 cells compared with control cells. Moreover, Dll4-Fc attenuates, at least in part, the classical and alternative NF-kB activation pathway by reducing Notch1 signaling. These results suggest that Dll4-Notch signaling in cancer cells plays a critical role in liver metastasis of SCLC by regulating NF-kB signaling.

A Novel Targeting Therapy of Malignant Mesothelioma Using Anti-Podoplanin Antibody

“…Cell lysate (15 mg/lane) was separated by SDS-PAGE. Immunoblotting was conducted as previously described (41).…”

Simultaneous blockade of VEGF and Dll4 by HD105, a bispecific antibody, inhibits tumor progression and angiogenesis

“…14,15 Several preclinical xenograft studies have shown that Dll4/ Notch blockade inhibited tumor progression by promoting the hyperproliferation of endothelial cells, which resulted in an increase in vascular density but a decrease in functional patent tumor vasculature. [16][17][18][19][20] In addition to the effects of Dll4 blockade on tumor vasculature, Dll4/Notch inhibition is known to reduce cancer stem cells (CSCs), which are an important cancer cell population for malignant tumor progression. 21 Therefore, Dll4 is now recognized as a promising target for improved efficacy in cancer treatment.…”

“…Moreover, combination treatment with VEGF and Dll4 inhibitors has demonstrated a more effective regression of tumor vessels and inhibition of tumor progression in several cancer xenograft models compared to VEGF or Dll4 blockade alone. [14][15][16][17][18][19][20] Based on this scientific evidence, we developed HD105, a bispecific antibody that targets VEGF and Dll4 simultaneously. This bispecific antibody consists of an anti-VEGF bevacizumab-similar IgG backbone linked with a Dll4-binding singlechain Fv.…”

Expression and influence of Notch signaling in oral squamous cell carcinoma

“…Dysregulation of Notch receptors, ligands, or target genes is noted in various cancer cells (1,2). Notch signaling inhibition has been demonstrated to attenuate cancer cell proliferation/cell cycle progression, to decrease cancer cell viability, and to increase cell apoptosis in various types of cancer (1,(3)(4)(5)(6). Furthermore, Notch signaling inhibition is proposed as an alternative adjuvant therapy for radiotherapy and chemotherapy (7,8).…”