Ko S C, Cheon J, Kao C, Gotoh A, Shirakawa T, Sikes R A, Karsenty G, Chung L W
Molecular Urology and Therapeutics Program, Department of Urology, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
Cancer Res. 1996 Oct 15;56(20):4614-9.
Osteocalcin (OC), a noncollagenous bone matrix protein, is expressed in high levels by osteoblasts. To determine whether the OC promoter mediates cell-specific gene expression in cells of osteoblast lineage, we constructed a recombinant adenovirus, Ad-OC-TK, which contains the OC promoter that drives the expression of herpes simplex virus thymidine kinase (TK). We tested the expression of TK by this virus in osteoblast cell lines as well as in non-osteoblastic cell lines by assessing the enzyme activity of TK in vitro. Whereas the OC promoter failed to drive the expression of the TK gene in several non-osteoblastic cell lines such as WH, a human bladder transitional carcinoma, and NIH 3T3, an embryonic mouse fibroblast cell line, the OC promoter mediated high levels of expression in osteoblast cell lines including murine ROS and human MG-63 cells. The addition of acyclovir (ACV), a pro-drug for the inhibition of cell proliferation, resulted in the induction of osteoblast-specific cell death in vitro. Intratumoral injection of Ad-OC-TK into murine ROS osteosarcoma abolished tumor growth in a host treated with subsequent i.p. ACV injection in vivo. The Ad-OC-TK virus plus ACV treatment appears to be highly selective in blocking the growth of both murine and human osteosarcoma cell lines in vitro and murine osteosarcoma in vivo.
骨钙素（OC）是一种非胶原蛋白骨基质蛋白，由成骨细胞高水平表达。为了确定OC启动子是否介导成骨细胞谱系细胞中的细胞特异性基因表达，我们构建了一种重组腺病毒Ad-OC-TK，其包含驱动单纯疱疹病毒胸苷激酶（TK）表达的OC启动子。我们通过在体外评估TK的酶活性，测试了该病毒在成骨细胞系以及非成骨细胞系中TK的表达。虽然OC启动子未能在几种非成骨细胞系中驱动TK基因的表达，如人膀胱移行癌WH和胚胎小鼠成纤维细胞系NIH 3T3，但OC启动子在包括小鼠ROS和人MG-63细胞在内的成骨细胞系中介导了高水平的表达。添加阿昔洛韦（ACV），一种用于抑制细胞增殖的前体药物，导致体外成骨细胞特异性细胞死亡的诱导。将Ad-OC-TK瘤内注射到小鼠ROS骨肉瘤中，在随后腹腔注射ACV治疗的宿主体内消除了肿瘤生长。Ad-OC-TK病毒加ACV治疗在体外阻断小鼠和人骨肉瘤细胞系的生长以及在体内阻断小鼠骨肉瘤的生长方面似乎具有高度选择性。
