Cancer Breakthrough: 'Like an Arrow That Hits Only the Bullseye'

In a major step forward for cancer care, researchers at ChristianaCare’s Gene Editing Institute have shown that disabling the NRF2 gene with CRISPR technology can reverse chemotherapy resistance in lung cancer. The approach restores drug sensitivity and slows tumor growth. The findings were published Nov. 13, 2025, in the online edition of Molecular Therapy Oncology.

This breakthrough stems from more than a decade of research by the Gene Editing Institute into the NRF2 gene, a known driver of treatment resistance. The results were consistent across multiple in vitro studies using human lung cancer cell lines and in vivo animal models. “We’ve seen compelling evidence at every stage of research,” said Kelly Banas, Ph.D., lead author of the study and associate director of research at the Gene Editing Institute. “It’s a strong foundation for taking the next step toward clinical trials.”

The study focused on lung squamous cell carcinoma, an aggressive and common form of non-small cell lung cancer (NSCLC) that accounts for 20% to 30% of all lung cancer cases, according to the American Cancer Society. It’s estimated that over 190,000 people in the U.S. will be diagnosed in 2025. While the research centered on this cancer type, the implications are broader. Overactive NRF2 contributes to chemotherapy resistance in several solid tumors, including liver, esophageal and head and neck cancers. The results suggest a CRISPR-based strategy targeting NRF2 could help resensitize a wide range of treatment-resistant tumors to standard chemotherapy. “This is a significant step toward overcoming one of the biggest challenges in cancer therapy – drug resistance,” Banas said. “By targeting a key transcription factor that drives resistance, we’ve shown that gene editing can re-sensitize tumors to standard treatment. "We’re hopeful that in clinical trials and beyond, this is what will allow chemotherapy to improve outcomes for patients and could enable them to remain healthier during the entirety of their treatment regimen.”

The research zeroed in on a tumor-specific mutation, R34G, in the NRF2 gene, which acts as a master regulator of cellular stress responses. When overactive, NRF2 helps cancer cells withstand chemotherapy.

Using CRISPR/Cas9, the team engineered lung cancer cells with the R34G mutation and successfully knocked out NRF2. This restored sensitivity to chemotherapy drugs such as carboplatin and paclitaxel. In animal models, tumors directly treated with CRISPR to knockout NRF2 grew more slowly and responded better to treatment. “This work brings transformational change to how we think about treating resistant cancers,” said Eric Kmiec, Ph.D., senior author of the study and executive director of the Gene Editing Institute. “Instead of developing entirely new drugs, we are using gene editing to make existing ones effective again.”

One of the most promising discoveries was that disrupting NRF2 in just 20% to 40% of tumor cells, was enough to improve the response to chemotherapy and shrink tumors. This insight is particularly relevant for clinical use, where editing every cancer cell may not be feasible. To test therapy in mice, the researchers used lipid nanoparticles (LNPs), a non-viral method with high efficiency and low risk of unintended, off-target effects. Sequencing confirmed that the edits were highly specific to the mutated NRF2 gene, with minimal unintended changes elsewhere in the genome. "The power of this CRISPR therapy lies in its precision. It's like an arrow that hits only the bullseye," said Banas. "This level of specificity with minimal unanticipated genomic side effects offers real hope for the cancer patients who could one day receive this treatment." To make a gift toward scientific innovation at ChristianaCare, click here.