EWS/Fli-1 chimeric fusion gene upregulates vascular endothelial growth factor-A.
Vascular endothelial growth factor (VEGF)-A plays an important role in the pathological angiogenesis that occurs in soft-tissue sarcoma and in about half of Ewing's sarcoma cases, where it is highly overexpressed. EWS/Fli-1 is considered to be a transcriptional activator and to play a significant role in tumorigenesis of Ewing's sarcoma. However, the relationship between EWS/Fli-1 and VEGF-A is still unclear. The aim of this research is to investigate the relationship between EWS/Fli-1 and VEGF-A, and to determine whether small interfering RNA (siRNA)-targeting of VEGF-A can be developed as a novel treatment for Ewing's sarcoma. Knockdown of EWS/Fli-1 using siRNA on a Ewing's sarcoma cell line (A673) suppressed VEGF-A expression, and transfection of EWS/Fli-1 into a human osteosarcoma cell line increased VEGF-A expression. To inhibit VEGF-A secretion from Ewing's sarcoma, we developed a chemically synthesized siRNA that targets VEGF-A. Transfection of the VEGF siRNA into the Ewing's sarcoma cell line significantly suppressed VEGF-A secretion by up to 98% in vitro, compared with a control. In vivo, we established Ewing's sarcoma xenograft models and performed intratumoral injection of the siRNA mixed with atelocollagen. We observed that the inhibition of tumor growth occurs in a dose-dependent manner. Histological examination revealed decreased microvessel density and morphological change around microvessels in the Ewing's sarcoma xenografts treated with the siRNA. It is considered that a combination of chemically synthesized siRNA that targets VEGF-A and atelocollagen might be a novel and effective option for treating Ewing's sarcoma that secretes VEGF-A.
Nagano
Akihito
A
Department of Orthopedic Surgery, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Japan.
Ohno
Takatoshi
T
Shimizu
Katsuji
K
Hara
Akira
A
Yamamoto
Takatoshi
T
Kawai
Gou
G
Saitou
Mitsuru
M
Takigami
Iori
I
Matsuhashi
Aya
A
Yamada
Kazunari
K
Takei
Yoshifumi
Y
D017398:Alternative Splicing; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control; D003094:Collagen / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000502:physiology*; D050939:Gene Fusion; D006801:Humans; D007124:Immunoenzyme Techniques; D051379:Mice; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
C106032:EWS1-WT1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C059821:atelocollagen; D003094:Collagen