Turning cancer cells to cancer killers, vaccines: Study

Scientists are harnessing a new way to turn cancer cells into potent, anti-cancer agents, according to a study.

According to the study, investigators have developed a new cell therapy approach to eliminate established tumours and induce long-term immunity, training the immune system so that it can prevent cancer from recurring.

In the latest work from Brigham and Women's Hospital, the team of researchers tested their dual-action, cancer-killing vaccine in an advanced mouse model of the deadly brain cancer glioblastoma, with promising results, said the study. Findings are published in the journal Science Translational Medicine.

"Our team has pursued a simple idea: to take cancer cells and transform them into cancer killers and vaccines," said corresponding author Khalid Shah, director of the Centre for Stem Cell and Translational Immunotherapy (CSTI) and the vice chair of research in the Department of Neurosurgery at the Brigham and faculty at Harvard Medical School and Harvard Stem Cell Institute (HSCI).

"Using gene engineering, we are repurposing cancer cells to develop a therapeutic that kills tumour cells and stimulates the immune system to both destroy primary tumours and prevent cancer," said Shah.

Cancer vaccines are an active area of research for many labs, but the approach that Shah and his colleagues have taken is distinct, the study said.

Instead of using inactivated tumour cells, the team repurposes living tumour cells, which possess an unusual feature. Like homing pigeons returning to roost, living tumour cells will travel long distances across the brain to return to the site of their fellow tumour cells.

Taking advantage of this unique property, Shah's team engineered living tumour cells using the gene-editing tool CRISPR-Cas9 and repurposed them to release tumour cell killing agent, the study said.

The engineered tumour cells were also designed to express factors that would make them easy for the immune system to spot, tag and remember, priming the immune system for a long-term anti-tumour response, the study said.

The team tested their repurposed CRISPR-enhanced and reverse-engineered therapeutic tumour cells (ThTC) in different mice strains including the one that bore bone marrow, liver and thymus cells derived from humans, mimicking the human immune micro-environment, the study said.

Shah's team also built a two-layered safety switch into the cancer cell, which, when activated, eradicates ThTCs if needed. This dual-action cell therapy was safe, applicable, and efficacious in these models, suggesting a road map toward therapy, the study said.

While further testing and development is needed, Shah's team specifically chose this model and used human cells to smooth the path of translating their findings for patient settings, the study said.

"Throughout all of the work that we do in the Centre, even when it is highly technical, we never lose sight of the patient," said Shah.

"Our goal is to take an innovative but translatable approach so that we can develop a therapeutic, cancer-killing vaccine that ultimately will have a lasting impact in medicine," said Shah.

Shah and colleagues note that this therapeutic strategy is applicable to a wider range of solid tumours and that further investigations of its applications are warranted.