期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：24
页码：14037-14042
DOI：10.1073/pnas.96.24.14037
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：An mRNA differential display comparison of mouse JB6 promotion-sensitive (P+) and -resistant (P-) cells identified a novel gene product that inhibits neoplastic transformation. The JB6 P+ and P- cells are genetic variants that differ in their transformation response to tumor promoters; P+ cells form anchorage-independent colonies that are tumorigenic, and P- cells do not. A differentially displayed fragment, A7-1, was preferentially expressed in P- cells at levels [≥]10-fold those in P+ cells, making its mRNA a candidate inhibitor of neoplastic transformation. An A7-1 cDNA was isolated that was identical to murine Pdcd4 gene cDNAs, also known as MA-3 or TIS, and analogous to human H731 and 197/15a. Until now, the function of the Pdcd4 protein has been unknown. Paralleling the mRNA levels, Pdcd4 protein levels were greater in P- than in P+ cells. Pdcd4 mRNA was also expressed at greater levels in the less progressed keratinocytes of another mouse skin neoplastic progression series. To test the hypothesis that Pdcd4 inhibits tumor promoter-induced transformation, stable cell lines expressing antisense Pdcd4 were generated from parental P- cells. The reduction of Pdcd4 proteins in antisense lines was accompanied by acquisition of a transformation-sensitive (P+) phenotype. The antisense-transfected cells were reverted to their initial P- phenotype by overexpression of a Pdcd4 sense fragment. These observations demonstrate that the Pdcd4 protein inhibits neoplastic transformation.
