Experimental evidence is beginning to support this idea. In models where mitochondrial fidelity is compromised, metabolic rewiring accelerates tumour development in APC-deficient intestines. The implications are profound. Rather than viewing mitochondrial dysfunction as a downstream consequence of cancer, we may need to consider it as a driver that preconditions tissue landscapes in ways that favour malignant transformation.
Shift in perspective
But the story does not end within the host cells. Remember, the intestine is not just a tissue: it’s an entire ecosystem. The gut microbiome, long appreciated for its key roles in energy homeostasis and immunity, is now emerging as a key architect of cancer risk.
In the context of APC-driven tumorigenesis, microbial communities may act as co-conspirators. For example, certain strains of Escherichia coli or Bacteroides fragilis produce genotoxins that directly damage host DNA, initiating cancer. Further, metabolites produced by dysfunctional microbiota such as secondary bile acids exacerbate oxidative stress and inflammation. These microbial outputs do not act in isolation, they intersect with host processes like mitochondrial function, immune signalling, and epithelial turnover. And, importantly, this relationship is not static – it’s dynamic in an age-dependent manner. So, it could well be the case that metabolites produced by microbiota that are beneficial during early life turn “sour” when mitochondrial, immune and intestinal fitness is compromised.
What makes this view particularly compelling is its alignment with the biology of ageing. Chronic low-grade inflammation, or “inflammageing,” shifts immune tone and thus cancer surveillance. Intestinal barrier function declines while microbial composition drifts creating a doom loop of inflammation. Mitochondria falter. Each of these hits alone may be tolerable, but together, they may tip the balance towards disease. In this view, cancer is less of a singular event and more an emergent property of a destabilised system that occurs with age.
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