Tumor-resident intracellular Bacteria promote Metastasis in Mice

Good news! Cancer is history (soon)! Towards a better understanding of the process of metastasis!

Life is complicated: Tumor-resident intracellular microbiota (Let this sink in!)

"... In mice with breast cancer, intracellular bacteria enhanced tumor cells’ ability to metastasize by improving their survival as they exit the primary tumor. ...
the discovery of bacteria inside tumor cells in 2017 ...
gut microbiota—the bacterial community in the gut which previous studies have shown to contribute to tumor progression. ..."

From the abstract:

"Tumor-resident intracellular microbiota is an emerging tumor component that has been documented for a variety of cancer types with unclear biological functions. Here, we explored the functional significance of these intratumor bacteria, primarily using a murine spontaneous breast-tumor model MMTV-PyMT. We found that depletion of intratumor bacteria significantly reduced lung metastasis without affecting primary tumor growth. During metastatic colonization, intratumor bacteria carried by circulating tumor cells promoted host-cell survival by enhancing resistance to fluid shear stress by reorganizing actin cytoskeleton. We further showed that intratumor administration of selected bacteria strains isolated from tumor-resident microbiota promoted metastasis in two murine tumor models with significantly different levels of metastasis potential. Our findings suggest that tumor-resident microbiota, albeit at low biomass, play an important role in promoting cancer metastasis,  ..."

Bacteria in Tumors Promote Metastasis in Mice | The Scientist Magazine®

Tumor-resident intracellular microbiota promotes metastatic colonization in breast cancer (no public access)