High cell proliferation may protect against cancer, jellyfish study suggests

Caltech researchers have found evidence that high rates of cell proliferation can suppress early cancer development, contrary to the long-standing view that frequent cell division increases cancer risk. The study, published in the Proceedings of the National Academy of Sciences, combines mathematical modeling with experiments in moon jellyfish (Aurelia aurita), which rarely develop tumors even when exposed to carcinogens.

Former graduate student Anish Sarma built models linking cell proliferation, mutation, and death rates. The models predicted that tissues with high cell turnover can afford to be more aggressive in quality control, destroying slightly defective cells and replacing them easily—a process the authors call "proofreading." Surprisingly, the models showed that lowering proliferation rates could allow mutations to accumulate and lead to neoplasia.

To test the predictions, Sarma conducted experiments in moon jellyfish. Normal jellyfish exposed to carcinogens did not develop abnormal growths. When apoptosis (programmed cell death) was disabled, the animals developed neoplasms after carcinogen exposure. Blocking cell proliferation produced the same result. Restoring proliferation ability prevented neoplasia, supporting the idea that high cell flux enables effective proofreading.

The researchers suggest that cancer can be reframed as a failure of this proofreading system rather than solely a consequence of mutation accumulation. If the mechanism operates in humans, it could open a prevention strategy that encourages cell proliferation to clear abnormalities before tumors arise, rather than targeting cancer cells after they form.

The paradigm may also help explain childhood cancers, which occur before cells have had time to accumulate many mutations under traditional models. Sarma, now a pediatric resident, plans to investigate the model's applicability to early cancer development in children.

The work emerged from a collaboration between biologist Lea Goentoro and control-theory expert John Doyle. Goentoro's lab has developed tools to manipulate jellyfish in the laboratory, while Doyle has applied engineering principles to biological systems. The project was supported by the Army Research Office and Caltech's Carver Mead New Adventures Fund.