UCL Scientists Engineer γδT Cells to Target Chemotherapy-Resistant Bowel Cancer
Key Insights
University College London researchers have successfully engineered rare γδT cells (search) with stabilized interleukin-15 (search) and B7-H3 (search) antibodies to target slow-growing bowel cancer (search) cells that resist conventional chemotherapy.
The engineered cells demonstrated dual cytotoxic mechanisms (AIC and ADCC) that prevented tumor-mediated immune evasion and maintained robust killing activity across over 1,000 experimental conditions using patient-derived organoids.
This breakthrough addresses a critical clinical challenge, as bowel cancer (search) claims over 900,000 lives annually worldwide, with slow-cycling cancer cells often surviving chemotherapy and causing aggressive relapses.
University College London scientists have achieved a significant breakthrough in cancer immunotherapy by engineering rare γδT cells (search) to effectively eliminate chemotherapy-resistant bowel cancer (search) cells. The research addresses a critical clinical challenge in treating bowel cancer, which claims over 900,000 lives annually worldwide.
Targeting Slow-Growing Cancer Cells
Traditional chemotherapy primarily targets rapidly dividing cancer cells, leaving behind quiescent or slow-cycling populations that evade destruction and later cause relapse. These residual cells are often more aggressive and less responsive to subsequent treatments, creating an urgent need for therapies capable of overcoming this resilience.
The UCL team focused on γδT cells (search), a rare subset of immune cells that possess unique properties making them promising for cancer treatment. Unlike more common αβT cells that identify threats through antigen presentation via MHC molecules (search), γδT cells have innate-like abilities to detect cellular stress markers without reliance on classical antigen presentation, enabling rapid and versatile immune responses.
Engineering Enhanced Immune Cells
The researchers isolated γδT cells (search) from seven healthy donors and employed lentiviral vectors to transduce these cells with a gene encoding stabilized interleukin-15 (search) (stIL-15). This cytokine variant enhances T cell survival and proliferation, equipping the γδT cells with prolonged viability and sustained cytotoxic potential.
To amplify anti-tumor efficacy, a subset of these engineered γδT cells (search) was further modified to express an antibody against B7-H3 (search), an immune checkpoint protein commonly overexpressed on bowel cancer (search) cells. This modification facilitated targeted recognition and activated dual cytolytic mechanisms: Antibody-Independent Cytotoxicity (AIC) and Antibody-Dependent Cellular Cytotoxicity (ADCC).
Breakthrough Results in Patient-Derived Models
The functional capacity of these modified immune cells was evaluated using patient-derived tumor organoids—three-dimensional cellular culture systems that authentically replicate the tumor microenvironment's complexity and heterogeneity. Across over 1,000 experimental conditions encompassing organoids from ten bowel cancer (search) patients, the supercharged γδT cells (search) exhibited remarkable persistence and potency.
Unlike unmodified γδT cells (search), which succumbed to tumor-mediated immunosuppression and cellular exhaustion, engineered cells maintained robust viability and cytotoxic function over extended periods. When γδT cells relied solely on their native antibody-independent killing, tumor cells orchestrated adaptive resistance by altering immune signaling pathways—effectively "rewiring" the γδT cells into a diminished state.
However, multi-modal attack strategies empowered by the B7-H3 antibody (search)'s facilitation of both AIC and ADCC restored the functional wiring of γδT cells (search). This dual-pronged assault decisively eliminated cancer cells, including slow-dividing subsets impervious to chemotherapy.
Clinical Implications and Future Potential
Professor Chris Tape, co-corresponding author, emphasized the translational implications: "By providing γδT cells (search) with multiple avenues to attack, we can circumvent the tumor's defensive mechanisms and sustain an effective anti-cancer response. This advancement propels us closer to novel immunotherapies for refractory bowel cancer (search)."
Dr. Jonathan Fisher, architect of the engineered γδT cell platform, highlighted the broader potential to extend these therapies across other solid tumors, a notoriously difficult arena for immunotherapies due to complex tumor-immune interactions.
Technological Innovation
A pivotal component of the research was deploying UCL's 'phenoscaping' technology, a sophisticated single-cell analytical framework that offers unprecedented resolution in mapping cellular phenotypes and dynamic interactions within tumor-immune ecosystems. This tool elucidated the cellular trajectories and molecular adaptations driving the differential outcomes between engineered and unmodified γδT cell populations.
Advantages for Clinical Translation
Central to the promise of γδT cell-based immunotherapy is their unique biological distinction from αβT cells, which dominate current T cell therapies but require autologous sourcing to minimize graft-versus-host disease. γδT cells (search) possess the intrinsic capacity for allogeneic transfer, meaning therapeutically potent cells could be derived from healthy donors, thereby surmounting logistical and manufacturing obstacles that hamper widespread accessibility of personalized T cell therapies.
The research underscores a critical paradigm shift: engineering immune cells not merely for specificity but for resilience and multi-modal functionality can empower sustained tumor eradication even in the face of dynamic tumor resistance mechanisms. The study was supported by Cancer Research UK, the Medical Research Council, and the Wellcome Trust.