Adachi Y, Reynolds P N, Yamamoto M, Grizzle W E, Overturf K, Matsubara S, Muramatsu T, Curiel D T
Department of Medicine, University of Alabama at Birmingham, 35294, USA.
Cancer Res. 2000 Aug 15;60(16):4305-10.
It is important to develop a system to express therapeutic genes in tumor cells with sufficient selectivity for cancer gene therapy. Midkine (MK) is a newly identified heparin-binding growth factor that is transiently expressed in the early stages of retinoic acid-induced differentiation of embryonal carcinoma cells. It has been reported that many human malignant tumors express high levels of MK mRNA or protein. However, no MK expression is detected in human or mouse liver. These interesting features of MK led us to examine the MK promoter as a candidate for tumor-specific gene expression. We thus developed new recombinant adenoviral (Ad) vectors containing either luciferase reporter gene (AdMKLuc) or herpes simplex thymidine kinase gene (AdMKTK) under the control of the human MK promoter. AdMKLuc achieved relatively high activity in Wilms' tumor (G-401) and neuroblastoma (SK-N-SH) cell lines. In addition, AdMKTK induced marked cell death in response to ganciclovir (GCV) in these same lines. Conversely, very low activity of the MK promoter was observed in mouse liver in vivo compared with the cytomegalovirus promoter. Importantly, AdMKTK + GCV did not induce liver toxicity, whereas substantial toxicity was seen with AdCMVTK + GCV treatment. On the basis of these findings, we conclude that the MK promoter is a candidate tumor-specific promoter for Wilms' tumor or neuroblastoma.
开发一种能够在肿瘤细胞中充分选择性地表达治疗性基因的系统对于癌症基因治疗至关重要。中期因子（MK）是一种新发现的肝素结合生长因子，在维甲酸诱导的胚胎癌细胞分化早期短暂表达。据报道，许多人类恶性肿瘤表达高水平的MK mRNA或蛋白质。然而，在人或小鼠肝脏中未检测到MK表达。MK的这些有趣特征促使我们研究MK启动子作为肿瘤特异性基因表达的候选者。因此，我们开发了新的重组腺病毒（Ad）载体，其在人MK启动子控制下含有荧光素酶报告基因（AdMKLuc）或单纯疱疹胸苷激酶基因（AdMKTK）。AdMKLuc在肾母细胞瘤（G-401）和成神经细胞瘤（SK-N-SH）细胞系中实现了相对较高的活性。此外，AdMKTK在这些相同细胞系中对更昔洛韦（GCV）产生明显的细胞死亡反应。相反，与巨细胞病毒启动子相比，在体内小鼠肝脏中观察到MK启动子的活性非常低。重要的是，AdMKTK + GCV未诱导肝毒性，而AdCMVTK + GCV治疗则出现明显毒性。基于这些发现，我们得出结论，MK启动子是肾母细胞瘤或成神经细胞瘤的候选肿瘤特异性启动子。
