Our interest in the tumor microbiome was sparked almost by chance. In 2012 we published a paper (Straussman et al, Nature 2012) demonstrating that stromal cells can modulate the sensitivity of cancer cells to chemotherapy. In one of these cases, we later found that it was a mycoplasma bacteria infecting the stromal cells rather than the stromal cells themselves that conferred resistance to the drug gemcitabine. We followed up on this story demonstrating that the majority of human pancreatic tumors contain bacteria and that, in many cases, these bacteria can degrade the drug gemcitabine into an inactive metabolite. (Geller et al, Science 2017)
In the last few years, we have developed multiple methods to better detect, characterize and visualize bacteria in human tumors. We also expanded our study to many additional tumor types finding that each tumor type has a distinct microbiome composition. Visualization assays demonstrated that intra-tumor bacteria are mostly intracellular and are present in both cancer and immune cells. We also found interesting associations between the specific tumor bacteria (or their functions) and the makeup of the specific microenvironment these bacteria live in. (Nejman et al, Science 2020).
We are currently studying various aspects of the tumor microbiome. Some examples include:
- Characterization of the human tumor microbiome across additional tumor types
- The effect of the tumor (and gut) microbiome on resistance to cytotoxic, targeted and immune mediated anti-cancer therapies.
- Characterization of the cross talk between bacteria and human cancer cells.
- Finding novel ways to manipulate the tumor/gut microbiome in order to affect different hallmarks of cancer.