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：2004
卷号：101
期号：30
页码：11099-11104
DOI：10.1073/pnas.0404310101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Reovirus is a benign human virus that was recently found to have oncolytic properties and is currently in clinical trials as a potential cancer therapy. We have previously demonstrated that activation of Ras signaling, a common event in cancer, renders cells susceptible to reovirus oncolysis. In this study, we investigate which elements downstream of Ras are important in reovirus infection. By using a panel of NIH 3T3 cells transformed with activated Ras mutated in the effector-binding domain, we found that only the RasV12G37 mutant, which was unable to signal to Raf or phosphatidylinositol 3-kinase but retained signaling capability to guanine nucleotide-exchange factors (GEFs) for the small G protein, Ral (known as RalGEFs), was permissive to reovirus. Expression of the activated mutant of the RalGEF, Rlf, also allowed reovirus replication. Specific inhibition of the Ral pathway by using dominant-negative RalA rendered normally permissive H-Ras cells (cells expressing activated Ras) resistant to reovirus. To further identify elements downstream of RalGEF that promote reovirus infection, we used chemical inhibitors of the downstream signaling elements p38 and JNK. We found that reovirus infection was blocked in the presence of the p38 inhibitor but not the JNK inhibitor. Together, these results implicate a Ras/RalGEF/p38 pathway in the regulation of reovirus replication and oncolysis.
关键词：Ras signaling pathway ; reovirus cancer therapy
