腎癌に対するInterferon-β/Liposome製剤を用いた遺伝子治療の開発

Abstract

腎癌に対するInterferon-β(IFN-β)/Liposome製剤(IAB-1)を用いた遺伝子治療の有効性を検討した.方法は, ヒト腎癌細胞株(NC65, ACHN)および腎癌初期培養細胞(RCC1, RCC2)に対しIAB-1によりIFN-β遺伝子を導入し, IFN-βの分泌と細胞障害活性を調べた.その結果, IFN-β遺伝子導入腎癌細胞培養上清中に有意なIFN-βの分泌を認めた.IAB-1処理により腎癌細胞に対しIFN-β蛋白より有意に強い細胞障害活性を認め, この作用はアポトーシス誘導によるものであった.また, 正常細胞にもIFN-β遺伝子導入は可能であったが, 細胞障害活性はなかった.NC65腎癌細胞のIAB-1処理ではISREの活性が増強され, IAB-1で培養するとc-myc遺伝子の発現増強を認めた.SCIDマウス皮下にNC65腎癌細胞株を移植し, 形成された腫瘍へのIAB-1注入で抗腫瘍効果を認め, この効果はIFN-β蛋白より強く, 投与量依存性であった

The anticancer activity of cationic multilamellar liposomes containing human IFN-beta gene (IAB-1) against renal cell carcinoma (RCC) was examined. Concentrations of IFN-beta protein were measured by an enzyme-linked immunosorbent assay. The cytotoxic activity of IAB-1 against RCC cells and normal renal proximal tubule endothelial cells (RPTEC5899) was examined by the microculture tetrazolium dye assay. For the in vivo study, the NC65 RCC cell line was inoculated into severe combined immunodeficiency mouse. The RCC cells treated with IAB-1 secreted significant amounts of IFN-beta protein. Significant in vitro cytotoxic activity of IAB-1 against RCC cells was observed. In contrast, treatment of RCC cells with recombinant IFN-beta protein resulted in less cytotoxicity. No significant cytotoxicity was seen in RPTEC5899 cells. Apoptosis was observed in RCC cells treated with IAB-1. The size of NC65 RCC cancers transfected with IAB-1 in mice was significantly smaller than that receiving injection of empty liposomes or recombinant IFN-beta protein. These findings show that IAB-1 may have significant antitumor activity against RCC, and suggest its potential clinical application for gene therapy against RCC.