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Updated: Dec 26, 2025
Genome-Wide CRISPR Screen for Unveiling Radiosensitive and Radioresistant Genes
Published on: May 23, 2025
RNA interference screening methods to identify proliferation determinants and mechanisms of resistance to immune
Yong-Wei Zhang1, Rochelle E Nasto2, Sandra A Jablonski1
1Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States.
Abstract:
We have used RNA interference (RNAi) screening technology to reveal unknown components of biological signaling pathways including survival mechanisms of estrogen-independent breast cancer cell growth and cancer cell resistance to immune attack. In this chapter, a detailed protocol describing the use of RNAi screening to identify factors important for the proliferation of estrogen-independent MCF7 breast cancer cells will be described. Resistance to therapies that target the estrogen pathway remains a challenge in the treatment of estrogen receptor-positive breast cancer. To address this challenge, small interfering-RNA (siRNA)-based libraries targeting an estrogen receptor (ER)- and aromatase-centered network, including 631 genes relevant to estrogen signaling, was designed and constructed for RNAi screening. This protocol will include the following parts: (1) selection of RNAi transfection reagent for specific cells; (2) optimization of RNAi screening conditions using Z'-factor; (3) procedure of ER-network gene siRNA library screening using automated machines under optimized experimental conditions; and (4) method of analysis for RNAi screening data to identify specific determinants important for cell proliferation. 46 genes were found to be selectively required for the survival of estrogen-independent MCF7-derived cells.
Insights
RNA interference (RNAi) screening identified 46 genes crucial for estrogen-independent breast cancer cell survival. This method aids in understanding resistance to estrogen-targeted therapies.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Estrogen receptor-positive breast cancer can develop resistance to endocrine therapies.
- Understanding the mechanisms of estrogen-independent growth is critical for improving treatment outcomes.
Purpose of the Study:
- To describe a detailed protocol for RNA interference (RNAi) screening to identify genes promoting estrogen-independent MCF7 breast cancer cell proliferation.
- To discover novel therapeutic targets for overcoming treatment resistance.
Main Methods:
- Design and construction of a small interfering-RNA (siRNA) library targeting 631 genes in an estrogen receptor (ER)- and aromatase-centered network.
- Optimization of RNAi screening conditions using the Z'-factor and automated screening of the ER-network gene siRNA library.
- Analysis of screening data to identify genes essential for cell proliferation.
Main Results:
- Identification of 46 genes selectively required for the survival of estrogen-independent MCF7-derived cells.
- The RNAi screening protocol provides a robust method for dissecting signaling pathways.
Conclusions:
- The study successfully identified key genes involved in estrogen-independent breast cancer cell survival.
- This RNAi screening approach offers a valuable tool for discovering therapeutic targets in resistant breast cancer.
