A preclinical study published in Molecular Therapy Oncology has shown that CRISPR-Cas9 gene editing can restore chemotherapy sensitivity in treatment-resistant models of head and neck and oesophageal squamous cell carcinoma, by disrupting the NRF2 (NFE2L2) stress-response pathway.
Chemotherapy resistance remains a major barrier to long-term disease control in squamous cancers, where platinum-based regimens are widely used but often lose effectiveness over time. NRF2 is a key transcription factor regulating oxidative stress and detoxification pathways, and its overactivity has been linked to resistance across multiple tumour types. In this study, researchers used CRISPR-Cas9 to selectively disrupt NRF2 in cancer cell models with established chemoresistance.
CLINICAL SUMMARY
What was examined
A preclinical study using CRISPR-Cas9 gene editing to disrupt the NRF2 stress-response pathway in chemoresistant head and neck and oesophageal squamous cancer models.
Key findings
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CRISPR disruption of NRF2 reduced NRF2 protein levels and downstream stress-response gene expression.
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Edited tumour models showed significantly increased sensitivity to cisplatin and fluoropyrimidine chemotherapy.
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The magnitude of chemosensitisation depended on the CRISPR target site within the NRF2 gene.
Clinical implications
- Gene editing of resistance pathways could represent a future strategy to restore chemotherapy effectiveness in refractory cancers.
- Translation to patients will require safe tumour-specific delivery, control of off-target effects, and integration with existing systemic therapies.
- The findings support NRF2 as a high-value biological target in squamous cancers with limited targeted treatment options.
CRISPR-mediated NRF2 disruption led to marked reductions in NRF2 protein expression and downstream stress-response genes. Edited cancer cells showed significantly increased sensitivity to standard chemotherapy agents, including cisplatin and fluoropyrimidines, compared with unedited resistant cells.
The degree of chemosensitisation depended on the CRISPR target site within the NRF2 gene, highlighting that guide RNA design and editing location influenced functional impact. Importantly, restored chemosensitivity was maintained over time in laboratory models, suggesting a durable biological effect rather than a transient stress response.
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The study further highlighted that no single biomarker was sufficient on its own, reinforcing the concept that composite or multi-parameter biomarker strategies may be required to meaningfully stratify patients.
These findings remain strictly preclinical, based on in-vitro and early experimental systems, and do not yet demonstrate clinical benefit in patients. Key challenges before translation to human therapy include the development of safe and efficient tumour-directed delivery systems, avoidance of off-target genomic effects, and integration of gene-editing approaches with existing chemotherapy regimens.
If these hurdles can be overcome, gene editing of resistance pathways could represent a new class of adjunctive therapy designed not to replace chemotherapy, but to restore or prolong its effectiveness. This strategy may be particularly relevant for squamous cancers, where targeted treatment options remain limited, and resistance to systemic therapy is common.
Rather than targeting oncogenic drivers, this approach focuses on disabling a core cellular defence mechanism that enables tumour survival under treatment pressure. The work reinforces NRF2 as a central regulator of chemoresistance biology and suggests that precision editing of resistance pathways could complement established cytotoxic regimens in future combination strategies.
Although clinical application remains distant, the study provides proof-of-concept that gene editing can be used not only to model resistance, but potentially to reverse it.
Paper: Rivera-Torres, Natalia et al. Target choice and exon skipping regulate CRISPR-directed gene editing of NRF2 in head/neck and esophageal cancer cells. Molecular Therapy Oncology, Volume 34, Issue 1, 201122. Access online here.
