Loss-of-Function Screening in Hematopoietic Malignancies

Abstract

Loss-of-function screens can be performed in vivo using retrovirally modified tumor cells. This approach has been used for decades in viral insertional mutagenesis to identify proto-oncogenes. In this approach, tumors are infected with a library of retroviral vectors expressing short-hairpin RNAs (shRNAs), such that each cell receives only a single retroviral insertion, and the representation of proviruses is monitored during ongoing tumor growth or before and after cancer therapy. The resulting tumors are highly chimeric, allowing a large diversity of loss-of-function phenotypes to be monitored simultaneously in an unbiased manner. This approach, used in conjunction with RNAi, can identify genes that are essential for the growth of diverse malignancies in vivo. Here, we outline this approach and discuss key challenges in performing these studies.