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Updated: Sep 8, 2025
Genome-Wide CRISPR Screen for Unveiling Radiosensitive and Radioresistant Genes
Published on: May 23, 2025
In vivo CRISPR screening links NFKB1 to endocrine resistance in ER⁺ breast cancer
Abstract:
Resistance to endocrine therapy (ET) remains a major clinical challenge in the treatment of estrogen receptor-positive (ER⁺) breast cancer, underscoring the need for novel therapeutic targets. To identify genetic drivers of ET resistance, we conducted an in vivo genome-wide CRISPR-Cas9 screen in MCF7 cells implanted into ovariectomized nude mice under estrogen-deprived conditions. NFKB1 emerged as a top candidate whose loss promoted estrogen-independent tumor growth and recurrence. Functional studies confirmed that NFKB1 deficiency enhanced tumorigenicity and conferred resistance to tamoxifen and fulvestrant both in vitro and in vivo. Mechanistically, transcriptomic and biochemical analyses revealed that NFKB1 loss activated canonical NF-κB signaling, leading to inflammatory gene induction and hyperactivation of ER signaling. Importantly, pharmacologic inhibition of NF-κB signaling restored ET sensitivity in NFKB1-deficient cells. Clinically, NFKB1 downregulation was enriched in ER⁺ breast tumors and associated with poor patient outcomes. Collectively, these findings establish NFKB1 as a key suppressor of ET resistance, uncover a mechanistic link between inflammation and ER reactivation, and highlight NF-κB signaling as a therapeutic vulnerability in NFKB1-deficient ER⁺ breast cancer.
Insights
Losing NFKB1 protein promotes estrogen receptor-positive breast cancer growth and resistance to endocrine therapy. Targeting NF-κB signaling may overcome this resistance in patients with NFKB1 deficiency.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Endocrine therapy (ET) resistance is a significant obstacle in treating estrogen receptor-positive (ER⁺) breast cancer.
- Identifying novel therapeutic targets is crucial for overcoming ET resistance.
Purpose of the Study:
- To identify genetic factors driving ET resistance in ER⁺ breast cancer.
- To investigate the role of NFKB1 in ET resistance and its underlying mechanisms.
Main Methods:
- Genome-wide CRISPR-Cas9 screen in vivo using MCF7 cells in mice under estrogen-deprived conditions.
- Functional assays (in vitro and in vivo) to assess the impact of NFKB1 deficiency on tumor growth and ET response.
- Transcriptomic and biochemical analyses to elucidate the molecular mechanisms involved.
- Clinical data analysis to correlate NFKB1 expression with patient outcomes.
Main Results:
- Loss of NFKB1 was identified as a key driver of estrogen-independent tumor growth and ET resistance.
- NFKB1 deficiency enhanced tumorigenicity and conferred resistance to tamoxifen and fulvestrant.
- NFKB1 loss activated NF-κB signaling, leading to inflammatory gene induction and ER signaling hyperactivation.
- Pharmacologic inhibition of NF-κB signaling restored ET sensitivity in NFKB1-deficient cells.
- Downregulation of NFKB1 in ER⁺ breast tumors correlated with poor patient outcomes.
Conclusions:
- NFKB1 acts as a critical suppressor of ET resistance in ER⁺ breast cancer.
- A mechanistic link between inflammation, NF-κB signaling, and ER reactivation was uncovered.
- NF-κB signaling represents a potential therapeutic vulnerability in NFKB1-deficient ER⁺ breast cancer.
