University of California scientists create cancer-fighting cells in body

Scientists at the University of California have developed a new method to treat blood cancers by reprogramming immune cells directly inside the patient’s body, rather than extracting and processing them in a laboratory.

For years, conventional CAR-T cell therapy has relied on a complex process that begins with extracting immune cells from the patient, sending them to specialised centres for genetic modification so they can recognise and kill cancer cells, and then reinfusing them into the patient.

Despite its high effectiveness, this process takes weeks and costs hundreds of thousands of dollars, making it inaccessible to many patients.

According to a new study published in Nature, the researchers have developed a technique that enables precise genetic modifications to be introduced directly inside the body, allowing T cells to produce chimeric antigen receptors (CARs) without the need for extraction or external processing.

This marks the first time scientists have successfully inserted a large DNA sequence into a specific site in human T cells without removing them from the body, avoiding the random integration associated with traditional virus-based methods.

The approach relies on a dual-particle delivery system carrying gene-editing tools (CRISPR-Cas9), often described as molecular “scissors” capable of precisely modifying DNA.

One of the particles delivers the CRISPR-Cas9 gene-editing machinery directly to T cells circulating in the body, enabling edits at a predetermined location in the genome - a significant advantage over conventional methods that randomly integrate CAR genes and may, in rare cases, lead to secondary cancers.

The second particle carries the new DNA required to produce cancer-fighting CAR receptors. This DNA is inserted only at a specific location in the T cell genome, controlled by a molecular “on switch” that is activated exclusively in T cells. The particles are also engineered to specifically target T cells and evade immediate destruction by the immune system.

In experiments conducted on mice with human-like immune systems, scientists successfully used this technique to treat multiple types of cancer, including acute lymphoblastic leukaemia and multiple myeloma, as well as some solid sarcoma tumor. Results showed the elimination of detectable cancer cells within two weeks in most animals, alongside significant in-body generation of CAR-T cells.

Researchers say this approach could surpass conventional methods not only in precision but also in efficiency, as cells produced inside the body appear more capable of expanding and retaining their functional properties compared to those prepared in laboratories. The development could also reduce the need for preparatory chemotherapy, lower costs, and accelerate access to treatment.

Despite the promising findings, the technology remains in the research and development stage and requires further clinical trials to confirm its safety and effectiveness in humans. The research team, in collaboration with scientific partners and a specialised company, is working to advance this technology towards clinical use, potentially enabling more accessible and cost-effective cancer treatments worldwide.