CRISPR turns off a cancer survival gene, restoring chemotherapy's power

Researchers have found a way to make drug-resistant lung cancer cells vulnerable again. By using CRISPR to disable a single gene called NRF2, scientists at ChristianaCare's Gene Editing Institute restored how tumors respond to standard chemotherapy drugs — the kind that had stopped working.

The study, published in Molecular Therapy Oncology, builds on over a decade of investigation into NRF2's role in helping cancer cells survive treatment. What makes this work significant is that it doesn't require inventing new drugs. Instead, it rewires existing cancer cells to respond to medicines already in use.

"We've seen compelling evidence at every stage of research," said Kelly Banas, lead author and associate director of research at the institute. "It's a strong foundation for taking the next step toward clinical trials."

How one mutated gene shields tumors

NRF2 normally helps cells manage stress. But when it becomes overactive — particularly through a specific mutation called R34G — cancer cells use it as a shield against chemotherapy. The researchers used CRISPR to cut out this gene entirely in lung cancer cells carrying the mutation. The result: cells became sensitive to common drugs like carboplatin and paclitaxel again. In animal models, tumors shrank faster and responded more reliably to treatment.

The focus was on lung squamous cell carcinoma, a fast-growing form that accounts for 20–30% of all non-small cell lung cancer cases. More than 190,000 people in the U.S. are expected to receive a lung cancer diagnosis this year alone.

But the implications reach further. NRF2 overactivity drives drug resistance in multiple cancer types — liver, esophagus, head and neck cancers all share this mechanism. That means the same CRISPR approach could eventually help restore chemotherapy's effectiveness across several different tumors.

A practical finding: you don't need to edit every cell

One finding with real clinical weight: editing just 20–40% of tumor cells was enough to enhance chemotherapy response and slow growth. This matters because reaching every cancer cell in a tumor isn't realistic in a living patient.

The team delivered CRISPR using lipid nanoparticles — tiny fat-based carriers that ferry the gene-editing machinery into cells without using viruses. The edits were highly precise, targeting only the mutated NRF2 gene with minimal unintended changes elsewhere in the genome. "This level of specificity with minimal unanticipated genomic side effects offers real hope," Banas said.

The next phase is clinical trials. If those succeed, this approach could let existing chemotherapy drugs work harder for patients who've developed resistance — potentially keeping them healthier throughout their treatment.