"Microbial allies: bacteria help fight against cancer"

✨ News story from #LMS @mrc-lms.bsky.social, covering the beautiful study led by #postdoc Daniel Martinez @dmartimarti.bsky.social - congrats! ✨

#PostdocAppreciationWeek #PAW2025
#Cancer #Microbiome #Chemotherapy

lms.mrc.ac.uk/microbial-al...

Can microbes enhance chemotherapy?

A new paper from the LMS shows how the tumour-associated microbiome can impact the efficacy of chemotherapy drugs.

#medsky #cancer #biomed

Thanks to all the collaborators (sorry if I'm missing someone!)

@kaletalab.bsky.social
@maringos.bsky.social
@alexisbarr.bsky.social
@frezzalab.bsky.social
@cochemelab.bsky.social
@mrc-lms.bsky.social
@imperialcollegeldn.bsky.social
@cecad.bsky.social
@cp-cellsystems.bsky.social

This work has been a wonderful conclusion of many years of hard work. I'm very happy to have worked with great scientists along the way, and I'm excited for the opportunities this research will open.

Yes, it matters! In collab with chemists at Newcastle University, we synthesized the pure bacterial form, it was more potent. Then we engineered a trimethyl ester version that was even more effective at stopping cancer cell growth. ⚗️

Finally, a super interesting thing we found. We'd been using a commercial racemic mixture of the two 2-MiCit enantiomers (2R,3S/2S,3R). But bacteria naturally produce only one of them: the (2R,3S) form. Does it matter?

A 2-MiCit - drug screening revealed that 2-MiCit synergises with nucleotide antimetabolites such as 5-FU! Proteomics revealed their joint effect greatly affects p53 and pyrimidine metabolism, and make HCT116 spheroids really struggle to grow.

How does 2-MiCit work? It hits the cell's mitochondria, impairing respiration. RNA-seq revealed this disrupts the cell cycle, DNA replication, and nucleotide metabolism. Crucially, it activates the p53 tumor suppressor pathway, which we confirmed with @alexisbarr.bsky.social

We found 2-MiCit powerfully inhibits proliferation across 20 cancer cell lines and shrinks 3D tumor spheroids. In a fly model of colon cancer (thanks @cochemelab.bsky.social !), 2-MiCit treatment reduced tumor spread and extended the flies' lifespan!

So, is this bacterial metabolite relevant in humans? With help from @kaletalab.bsky.social we predicted its production is significantly higher in the gut microbiomes of colorectal cancer patients. It is also present in cancer-associated microbiomes.

What does it actually do to cancer cells?

A gene-nutrient screen pointed to a key mechanism: metabolic rewiring downstream of pyruvate, affecting the TCA. After many more experiments using C. elegans one culprit emerged: 2-MiCit, a metabolite from the bacterial methylcitrate cycle! 🎯

Using a 4-way screening (bacteria + worm + drug + nutrient) we observed that sugars were able to impair 5-FU activity in C. elegans when fed with the the salvage pathway triple mutant, a super resistant strain for 5-FU effects.

We started with a basic question: how does nutrition affect the drug 5-FU? Using C. elegans & E. coli we saw the drug's effect drastically changed depending on the bacterial strain and the nutrients in their environment! We tested >70 different E. coli strains that further confirmed this! 🧪

Excited to share our latest work at Cabreiro lab!

Chemotherapy modulation by a cancer-associated microbiota metabolite

www.cell.com/cell-systems...

Here's what we discovered 🧵

PhD Timeline xkcd.com/3081