Single-vector inducible lentiviral RNAi system for oncology target validation

• Published in: Cell cycle (Georgetown, Tex.) Tex.), 2009-02, Vol.8 (3), p.498-504
• Main Authors: Wiederschain, Dmitri, Susan, Wee, Chen, Lin, Loo, Alice, Yang, Guizhi, Huang, Alan, Chen, Yan, Caponigro, Giordano, Yao, Yung-mae, Lengauer, Christoph, Sellers, William R., Benson, John D.
• Format: Article
• Language: English
• Subjects: Animals; Binding; Biology; Bioscience; Calcium; Cancer; Cell; Cell Line, Tumor; Cycle; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques - methods; Genetic Vectors - genetics; Genetic Vectors - metabolism; Humans; Landes; Lentivirus - genetics; Lentivirus - metabolism; Mice; Mice, Nude; Neoplasm Transplantation; Neoplasms - genetics; Neoplasms - metabolism; Neoplasms - pathology; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Organogenesis; Polycomb Repressive Complex 1; Proteins; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Repressor Proteins - genetics; Repressor Proteins - metabolism; Reproducibility of Results; RNA Interference
• ISSN: 1538-4101; 1551-4005
• DOI: 10.4161/cc.8.3.7701

The use of RNA interference (RNAi) has enabled loss-of-function studies in mammalian cancer cells and has hence become critical for  identifying and validating cancer drug targets.  Current transient siRNA and stable shRNA systems, however, have limited utility in accurately assessing the cancer dependency due to their short-lived effects and limited in vivo utility, respectively.  In this study, a single-vector lentiviral, Tet-inducible shRNA system (pLKO-Tet-On) was generated to allow for the rapid generation of multiple stable cell lines with regulatable shRNA expression.  We demonstrate the advantages and versatility of this system by targeting two polycomb group proteins, Bmi-1 and Mel-18, in a number of cancer cell lines.  Our data show that pLKO-Tet-On-mediated knockdown is tightly regulated by the inducer tetracycline and its derivative, doxycycline, in a concentration- and time-dependent manner.  Furthermore, target gene expression is fully restored upon withdrawal of the inducing agent.  An additional, 17 distinct gene products have been targeted by inducible shRNAs with robust regulation in all cases.  Importantly, we functionally validate the ability of the pLKO-Tet-On vector to reversibly silence targeted transcripts in vivo.  The versatile and robust inducible lentiviral RNAi system reported herein can therefore serve as a powerful tool to rapidly reveal tumor cell dependence.