乳酸アシドーシス環境におけるpH調節機構を介した腫瘍血管内皮細胞の生存

配架番号：242

乳酸アシドーシス環境におけるpH調節機構を介した腫瘍血管内皮細胞の生存 [全文の要約]

この博士論文全文の閲覧方法については、以下のサイトをご参照ください。配架番号：2426https://www.lib.hokudai.ac.jp/dissertations/copy-guides

乳酸アシドーシス環境におけるpH調節機構を介した腫瘍血管内皮細胞の生存 [論文内容及び審査の要旨]

配架番号：242

Tumor endothelial cells survive in lactic acidosis via the activity of pH regulators

配架番号：2426(主査) 教授 山下 啓子, 教授 近藤 亨, 教授 小林 弘一, 教授 田中 伸哉医学研究科（医学専攻

Comparison of characteristics of mouse immortalized normal endothelial cells, MS1 and primary cultured endothelial cells.

Tumor blood vessels support the progression of tumors by providing nutrition and oxygen required for growth. By acting as gatekeepers, they allow the metastasis of tumors to secondary locations. An important strategy in cancer therapy has been to target tumor blood vessels consequently inhibiting tumor angiogenesis. To date, antiangiogenic therapy being employed for cancer treatment have yielded profoundly good results. However, it has been shown that current antiangiogenic drugs have several problems, such as adverse side effects and drug resistance. Tumor endothelial cells (TEC), which line the inner layer of blood vessels of the tumor stromal tissue, are the main targets of the antiangiogenic therapies. TEC have been reported to differ significantly from endothelial cells resident in normal blood vessels. These differences provide a window through which TEC can be targeted solely with little or no impact on normal endothelial cells (NEC). Currently, as part of new antiangiogenic drug discovery processes, cell-based screening is being performed using thousands of small chemical compounds. For the success of such screening purposes, there is a need to obtain the right kind of cells and in adequate quantities. Primary–cultured endothelial cells isolated from murine / human blood vessels are the preferred choice. However, maintenance of the primary-cultured endothelial cells is costly and overtime these cells become senescent and perish. As a result, MS1, SV40 immortalized islet-derived endothelial cells, have been used in place of the primary-cultured cells. MS1 is commercially available with comparatively cheaper cell culture requirements. 　In this study, we compared the characteristics of MS1 and primary-cultured endothelial cells ; NEC and TEC to investigate the possibility of using MS1 cells for chemical screening in search of a new antiangiogenic drug. MS1 cells proliferate faster compared to TEC and upregulated the mRNA expressions of CD133 and Sca-1 genes. However, mRNA expression of most of the other genes, which were upregulated in TEC compared to NEC, were also expressed at lower levels in the MS1 cells. Furthermore, MS1 migrated at a slower rate and did not form tubes on matrigel, as opposed to the function of TEC. In conclusion, MS1 did not completely resemble NEC, nor TEC in function and gene expression. It is suggested that for chemical screening, primary-cultured TEC and the corresponding NEC would be a more ideal choice of cells

Novel antiangiogenic therapy targeting biglycan using tumor endothelial cell-specific liposomal siRNA delivery system

Tumor blood vessels play important roles in tumor progression and metastasis. Targeting tumor endothelial cells (TECs) is one of the strategies for cancer therapy. We previously reported that biglycan, a small leucine-rich proteoglycan, is highly expressed in TECs. TECs utilize biglycan in an autocrine manner for migration and angiogenesis. Furthermore, TEC-derived biglycan stimulates tumor cell migration in a paracrine manner leading to tumor cell intravasation and metastasis. In this study, we explored the therapeutic effect of biglycan inhibition in the TECs of renal cell carcinoma using an in vivo siRNA delivery system known as a multifunctional envelope-type nanodevice (MEND), which contains a unique pH-sensitive cationic lipid. To specifically deliver MEND into TECs, we incorporated cyclo(Arg-Gly-Asp-D-Phe-Lys) (cRGD) into MEND because alpha(V)beta(3) integrin, a receptor for cRGD, is selective and highly expressed in TECs. We developed RGD-MEND-encapsulating siRNA against biglycan. First, we confirmed that MEND was delivered into OS-RC-2 tumor-derived TECs and induced in vitro RNAi-mediated gene silencing. MEND was then injected intravenously into OS-RC-2 tumor-bearing mice. Flow cytometry analysis demonstrated that MEND was specifically delivered into TECs. Quantitative RT-PCR indicated that biglycan was knocked down by biglycan siRNA-containing MEND. Finally, we analyzed the therapeutic effect of biglycan silencing by MEND in TECs. Tumor growth was inhibited by biglycan siRNA-containing MEND. Tumor microenvironmental factors such as fibrosis were also normalized using biglycan inhibition in TECs. Biglycan in TECs can be a novel target for cancer treatment