並列タイトル等Characterization of stem marker positive tumor endothelial cells
幹細胞様腫瘍血管内皮細胞と血管新生
一般注記Tumor blood vessels play an important role in tumor progression and metastasis. It has been revealed that tumor endothelial cells (TECs) are different from normal endothelial cells (NECs) in various aspects. It has been reported that TECs had highly angiogenic phenotypes compared to NECs. For example, TECs showed greater proliferative activity and higher migration ability than NECs. In addition, angiogenesis related genes such as VEGF (vascular endothelial growth factor) or VEGF Receptor 2 were upregulated in TECs. Furthermore, TECs upregulated stem cell markers such as Sca-1, CD90 and MDR(Multidrug resistance) 1 compared to NECs. And they had a differentiation ability to osteoblasts. These results suggested that stem-like cells existed in tumor blood vessels. In this study, to reveal the biological role of stem-like TECs, we analyzed the expression 32 of ALDH(aldehyde dehydrogenase), which is one of the stem cell markers, in TECs and characterized ALDH (+) TECs. TECs were isolated from melanoma xenografted in nude mice and NECs were isolated from dermis of normal nude mice. ALDH mRNA expression and activity were higher in TECs than in NECs. Then, ALDH (+) / (-) TECs were sorted by flow cytometry to compare their characteristics. ALDH (+) TECs formed more tubes on Matrigel-coated plates and sustained those tubular networks longer compared to ALDH (-) TECs. Furthermore mRNA expression levels of VEGF and VEGFR2 were higher in ALDH (+) TECs than in ALDH (-) TECs. In addition, ALDH was expressed in tumor blood vessels in in vivo tumor blood vessels in mouse melanoma and oral carcinoma, but not in normal blood vessels. These findings indicate that ALDH (+) TECs had angiogenic phenotype. Stem-like TECs may have an essential role in tumor angiogenesis, and therefore contribute to tumor growth and metastasis.
腫瘍血管新生はがんの進展や転移に重要な役割を果たしている. 近年, 腫瘍血管内皮細胞 (Tumor endothelial cells: TECs) は正常血管内皮細胞 (Normal endothelial cells: NECs) に比べ様々な面で異なることがわかってきた. われわれもこれまで, TECs はNECs に比べ増殖能,遊走能が亢進しており,高い血管新生能をもつこと, さらにSca-1, CD90, MDR1, aldehyde dehydrogenase (ALDH) などの幹細胞マーカーを発現しており, 骨芽細胞への分化能をもつことを報告してきた. このことはTECs に幹細胞様の集団が存在する可能性を示唆していた.そこで,本研究は, 幹細胞様TECs の生物像を解明することを目的とし,ALDHの遺伝子発現および酵素活性が亢進しているTECsを幹細胞様集団として分離し, それらの性質を解析した.その結果,ALDH (+) TEC はALDH (-) TEC に比べ,管腔形成能が高かった. またALDH (+) TEC ではALDH (-) TEC に比べ,血管新生関連遺伝子vascularendothelial growth factor (VEGF) のレセプターであるVEGF Receptor 2 の発現が亢進していた. さらにヒトメラノーマおよび口腔がん皮下移植腫瘍の組織切片を用いた蛍光二重免疫染色により,in vivo 腫瘍血管においても,ALDH の発現が高い内皮細胞が存在することが示された.このことから,幹細胞マーカー陽性の腫瘍血管内皮細胞は高い血管新生能を有し,がんの進展や転移に重要な役割を果たしている可能性が示唆された.
(主査) 教授 飯田 順一郎, 教授 進藤 正信, 特任准教授 樋田 京子
歯学研究科(口腔医学専攻)
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受理日(W3CDTF)2015-02-03T05:25:05+09:00
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