1643P - Y-box binding protein-1 is involved in tumor angiogenesis and a promising therapeutic target

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Translational Research
Presenter Kentaro Shinkai
Citation Annals of Oncology (2014) 25 (suppl_4): iv564-iv573. 10.1093/annonc/mdu359
Authors K. Shinkai1, K. Nakano2, H. Onishi3, M. Tanaka4, M. Katano5
  • 1Department Cancer Therapy And Research, Kyushu University, 8120054 - Fukuoka/JP
  • 2Inovation Center Of Medical Recox Navigation, Kyushu-University, 8128582 - Fukuoka/JP
  • 3Cancer Therapy And Research, Kyushu University Hospital, 812-8582 - Fukuoka/JP
  • 4Surgery And Oncology, Kyushu University, 8128582 - Fukuoka/JP
  • 5Department Of Cancer Therapy And Research, Graduate School of Medical Sciences Kyushu University, 8120054 - Fukuoka-shi/JP

Abstract

Aim

Anti-angiogenesis is a promising strategy to control refractory solid cancers. A recent study has demonstrated that Y-box binding protein-1 (YB-1) is overexpressed in the angiogenic endothelial cells of tumor tissues as well as in cancer cells. The aim of this study was to elucidate the biological significance of YB-1 in vascular endothelial cells (EC) and to analyze whether YB-1 is a target molecule to control the angiogenic switch of tumor growth.

Methods

YB-1 expression in EC (HUVEC and HPAEC) was inhibited by specific small interfering RNAs (YB-1 siRNA) or antisense oligonucleotide (YB-1 ASO). The effects of YB-1 knockdown on the proliferation, apoptosis, cell cycle transition and tube formation of EC cells were evaluated by MTT assay, Annexin V-fluorescein isothiocyanate (FITC)/ propidium iodide (PI) staining, flow cytometry and tube formation assay, respectively. The changes of gene expression in EC by YB-1 knockdown were analyzed with DNA microarray, quantative RT-PCR and Western blotting. To examine the effect of YB-1 knockdown on tumor angiogenesis, we administered YB-1 ASO into subcutaneous tumors in colon(HCT116) and lung(A549) cancer xenograft mouse models, and evaluated tumor growth by measurement of tumor volume and microvascular density (MVD) by CD31 immunohistochemistry.

Results

Compared with the siRNA- or ASO-control, YB-1 knockdown by YB-1 siRNA or YB-1 ASO inhibited cell proliferation, induced G1 phase cell cycle arrest, increased the percentage of apoptotic cells in EC cells, and decreased the length of tubular network structure of EC cells significantly. The expressions of cell cycle- and apoptosis signaling-related factors (CCNB1, CCND, CDK1, CDK2, CDK4, p21, p27 and PARP1) were changed. In vivo experiment, local administration of YB-1 ASO inhibited tumor growth and induced significant decrease of MVD with down-regulation of YB-1 expression in tumor vessels.

Conclusions

These results suggest that YB-1 is a key factor for angiogenesis and may be a promising target for the treatment of refractory malignancies.

Disclosure

All authors have declared no conflicts of interest.