Team:Montpellier

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MICROBIOME

Scientists and physicians have long thought that cancers were sterile environments. However, it has recently been shown that, like almost everywhere in the human body, tumors were in fact profitable for microorganisms. More than that, studies revealed that each tumor located in different parts of the body have specific microbiomes with bacteria adapted to it. For example, we find bacteria assimilating smokes in lung cancer of smokers or even bacteria digesting gerbamicine, a chemotherapy molecule administered during cancer treatment [1]. As different phages infect different bacterial strains, it is important to identify the microbiome from cancer we want to target with our therapy in order to choose a compatible phage. Not all cancer microbiomes have been characterized. However, some information can be found on some cancers.

      PROSTATE

It is known that a healthy prostate has a lot of bacteria. So it is not surprising that tumors in this organ present a microbiome. The most abundant bacteria genus is Propionibacterium [2] which could be a valid target for our engineered phage.

      COLORECTAL

Like for the prostate, this organ is known to have an enriched microbiome. Microbiomes differ with cancer types, in this cancer it also differs with the location in the colon. If it is more distal the principal genus are Alistipes, Akkermansia, Halomonas and Shewanella. In the case of a proximal tumor, more Faecalibacterium, Blautia and Clostridium are found [3].

      PANCREAS

Another cancer associated with the digestive tract is pancreas cancer. It has been shown that Escherichia coli can migrate from the gut to the pancreas cancer [4] during its development however few articles mentioned its presence in tumoral microbiomes [5]. The major genus are Pseudomonas, Citrobacter and Klebsiella [6] .

      LUNGS

Next cancer is pulmonary cancer. Nowadays, the lungs microbiome is more and more studied, tumors included. Yet no particular phyla has been clearly identified but it has been shown that genus Veillonella and Megasphaera are characterizing lungs with cancer. [7]

      OVARY

Pediococcus, Burkholderia, Sphingomonas, Chryseobacterium, Enterococcus, Staphylococcus, Treponema and Francisella with the first one being slightly more abundant [8].

References

[1] D. Nejman et al. The Human tumor microbiome is composed of tumor type-specific intracellular bacteria. Science. (29th May 2020)
[2] Ilaria Cavarretta et al. The microbiome of the prostate tumor microenvironment. European Urology. (21 mars 2017)
[3] Burkhardt Flemer et al. Tumor-associated and non-tumor-associated microbiota in colorectal cancer. Gut microbiota journal. (18 mars 2016)
[4] Smruti Pushalkar et al. The Pancreatic cancer microbiome promotes oncogenesis by induction of innate and adaptive Immune suppression. Cancer discovery (April 2018)
[5] Poala Di Carlo et al. The microbiota of the bilio-pancreatic system: a cohort, STROBE-compliant study. Infection and Drug resistance (June 2019)
[6] Leore T. Geller et al, “Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine”, Science 2017
[7] Jisso Choi et al. Characterization of microbiome in patient with lung cancer comparing with benign mass-like lesion. European Respiratory journal. (septembre 2016)
[8] Sagarika Banerjee et al. The ovarian cancer oncobiome. Oncotarget. (30 mars 2017)