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Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death
Published on: October 21, 2012
Thorough validation of siRNA-induced cell death phenotypes defines new anti-apoptotic protein
Weilin Wu1, Emily Hodges, Christer Höög
1Center for Genomics and Bioinformatics, Karolinska Institute, Stockholm, SE-17177, Sweden. weilin.wu@cgb.ki.se
Abstract:
Loss-of-function by means of RNA interference in cultured human cells enables rapid pathway dissection on a genome-scale. Improved siRNA design and key validation protocols are required to eliminate falsely identified phenotypes resulting from potential off-target consequences. Here, we demonstrate a validation strategy involving several steps for verifying cell death phenotypes revealed during loss-of-function screening. First, from a set of 45 novel human genes we identified gene candidates that, when silenced, induce apoptosis in cultured HeLa cells. For those candidates, we performed more extensive validation with multiple effective siRNAs. In addition, we designed rescue experiments involving candidate genes delivered exogenously and containing silent mutations in the siRNA target regions. Rescue of the observed knockdown phenotype demonstrated an original and more stringent validation of the siRNA's selectivity and the phenotype specificity for the target gene. As a result, our data reveals an anti-apoptotic function for novel human breast adenocarcinoma marker BC-2, adding new depth to BC-2's description as a putative tumor marker involved in cancer related pathways.
Insights
This study validates RNA interference screening methods to accurately identify genes causing cell death. A novel validation strategy confirmed an anti-apoptotic role for breast cancer marker BC-2.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- Genome-scale loss-of-function screening using RNA interference (RNAi) is crucial for pathway dissection in human cells.
- Ensuring accuracy in RNAi screening requires improved siRNA design and validation to prevent off-target effects and false phenotypes.
- Cell death phenotypes identified in loss-of-function screens necessitate rigorous verification.
Purpose of the Study:
- To develop and demonstrate a multi-step validation strategy for cell death phenotypes identified through genome-scale RNAi screening.
- To rigorously validate gene candidates that induce apoptosis upon silencing in cultured human cells.
- To confirm the specificity of RNAi-induced phenotypes and the selectivity of siRNAs used.
Main Methods:
- Initial screening of 45 novel human genes using RNA interference (RNAi) to identify apoptosis-inducing candidates in HeLa cells.
- Secondary validation using multiple effective siRNAs for confirmed gene candidates.
- Rescue experiments involving exogenous delivery of mutated candidate genes (silent mutations in siRNA target regions) to confirm phenotype specificity.
Main Results:
- Identified several novel human gene candidates that induce apoptosis when silenced.
- The developed validation strategy, including rescue experiments, confirmed the specificity of the observed phenotypes for the targeted genes.
- Demonstrated an anti-apoptotic function for the novel human breast adenocarcinoma marker BC-2.
Conclusions:
- The proposed validation strategy provides a stringent method for verifying RNAi-screened cell death phenotypes, ensuring target specificity.
- The findings reveal a previously unrecognized anti-apoptotic role for BC-2, expanding its significance in cancer-related pathways.
- This approach enhances the reliability of genome-scale RNAi screening for biological discovery.
