Whitesell L, Rosolen A, Neckers L M
Tumor Cell Biology Section, National Cancer Institute, Bethesda, Maryland 20892.
Mol Cell Biol. 1991 Mar;11(3):1360-71. doi: 10.1128/mcb.11.3.1360-1371.1991.
Neuroectodermal tumors of childhood provide a unique opportunity to examine the role of genes potentially regulating neuronal growth and differentiation because many cell lines derived from these tumors are composed of at least two distinct morphologic cell types. These types display variant phenotypic characteristics and spontaneously interconvert, or transdifferentiate, in vitro. The factors that regulate transdifferentiation are unknown. Application of antisense approaches to the transdifferentiation process has allowed us to explore the precise role that N-myc may play in regulating developing systems. We now report construction of an episomally replicating expression vector designed to generate RNA antisense to part of the human N-myc gene. Such a vector is able to specifically inhibit N-myc expression in cell lines carrying both normal and amplified N-myc alleles. Inhibition of N-myc expression blocks transdifferentiation in these lines, with accumulation of cells of an intermediate phenotype. A concomitant decrease in growth rate but not loss of tumorigenicity was observed in the N-myc nonamplified cell line CHP-100. Vector-generated antisense RNA should allow identification of genes specifically regulated by the proto-oncogene N-myc.
儿童神经外胚层肿瘤提供了一个独特的机会，可用于研究可能调控神经元生长和分化的基因的作用，因为许多源自这些肿瘤的细胞系至少由两种不同形态的细胞类型组成。这些类型表现出不同的表型特征，并在体外自发地相互转化，即转分化。调节转分化的因素尚不清楚。将反义方法应用于转分化过程，使我们能够探究N - myc在调控发育系统中可能发挥的精确作用。我们现在报告构建了一种游离复制表达载体，该载体旨在产生针对人N - myc基因部分区域的反义RNA。这样的载体能够特异性抑制携带正常和扩增N - myc等位基因的细胞系中的N - myc表达。在这些细胞系中，N - myc表达的抑制会阻断转分化，导致中间表型细胞的积累。在N - myc未扩增的细胞系CHP - 100中，观察到生长速率随之降低，但致瘤性并未丧失。载体产生的反义RNA应有助于鉴定由原癌基因N - myc特异性调控的基因。
