Health Science Reviews

By Lutendo Sikhwari

Imagine going to battle with cancer. The enemy is clear, and the mission is to destroy as many cancer cells as possible. Doctors deploy one of their strongest weapons: chemotherapy. For many patients, this treatment works wonders, shrinking tumours and killing off rebellious cells.

But here’s the twist most people never hear, not all cancer cells die under chemotherapy’s assault. Some become “zombies”, cells that stop dividing, a state known as senescence, but don’t truly die. They linger in the shadows, planning their next move.

The Big question: what are these cells up to?

In this study, researchers from Tulane University and their collaborators set out to unravel the fate of these so-called “senescent” cancer cells, particularly in breast cancer, after chemotherapy. Their mission? To uncover the creative survival strategies these persistent cells employ, and to answer a burning question: Are these cells simply dormant, or do they possess a more cunning secret?

A Shocking Discovery: Cancer Cell Cannibalism

Using laboratory models and real tumour samples, the team observed an astonishing phenomenon: after chemotherapy, these “zombie” cancer cells didn’t just sit around. Instead, they started gobbling up their neighbours, engulfing and digesting other cancer cells like microscopic cannibals. This wasn’t a rare occurrence; about 15-20% of the senescent cells were caught in the act, and sometimes one cell would swallow several others. They utilised their enlarged internal “stomachs,” known as lysosomes, to break down the unlucky cells and fuel their own survival, a trick worthy of a sci-fi plot.

Why This Matters: Beyond Survival, A Recipe For Relapse

Why would a cancer cell turn cannibal? The answer seems simple: survival. By devouring their peers, these “zombie” cells gain the resources to persist long-term, even resisting further treatment. The researchers also found that these survivors are responsible for releasing a cocktail of molecules that may encourage cancer to resurge, explaining, in part, why relapse happens even after apparently successful chemotherapy.

Reimaging The Cancer Fight

This research reframes our image of lingering cancer cells. They are not just dormant; they are active, resourceful, and dangerous. Understanding this cannibalistic behaviour opens new possibilities: what if we could stop these cells from feeding on their neighbours? Could we make chemotherapy not just effective in the short term, but powerful enough to prevent relapses?

So, next time you think of cancer therapies, remember science is not just fighting the known enemy, it’s uncovering the cunning survival tricks that keep cancer coming back, with the hope of finally closing every loophole.

Reference

Tonnessen-Murray, C.A., Lozano, G. and Jackson, J.G., 2019. Chemotherapy-inducedsenescent cancer cells engulf other cells to enhance their survival. Journal of CellBiology, 218(11), pp.3827–3844. https://doi.org/10.1083/jcb.201904051