Bacteria can make tumors more aggressive – GeekWire

Tumor cells in a bacterially colonized petri dish (left) show greater migration from a central cluster than tumor cells that are not colonized (right). (Jorge Luis Galeano NiƱo et al. Image)

Tumor-colonizing bacteria may contribute to cancer progression and metastasis, suggests new research from the Fred Hutchinson Cancer Center.

The oral bacterium nucleated Fusobacterium, a component of dental plaque, it is known to be present in oral cavity and colorectal cancers. Two studies released this week took a closer look at how F. nucleated and other microbes affect such tumors.

Using microscopy and techniques to measure proteins and RNA, the researchers discovered this F. nucleated and other bacteria populate areas of tumors that show suppression of the immune system. The bacteria-infected cancer cells also had alterations in the molecular pathways involved in cell migration and metastasis, among other processes.

To see if the bacteria had a direct effect on tumors, the researchers infected clusters of chorectal cancer cells in a petri dish with F. nucleated. They found that the infected clusters attract a type of cell that may be involved in immunosuppression. Infected cells were also more likely to migrate out of the cluster.

The study, published in Naturesuggests that bacteria may promote cancer progression by promoting metastasis and creating an environment that resists tumor destruction by the immune system. The data “point to a crucial role for intratumor bacteria, reinforcing the need for further research in this area and demonstrating the technical feasibility of such work,” according to a separate commentary in the journal.

The findings are also consistent with previous studies showing this F. nucleated is associated with tumor progression and worse outcomes in patients with colorectal cancer. They also suggest that measures to control the bacteria could potentially play a role in cancer treatment.

Because broad-spectrum antibiotics kill off beneficial bacteria, researchers looked for compounds that specifically inhibited them F. nucleated.

In a second study in Cell reports, have shown that a common chemotherapy drug, 5-fluorouracil, is also a potent inhibitor of the microbe. Other types of bacteria in colorectal cancers might also metabolize 5-fluorouracil, suggesting they might contribute to chemotherapy resistance.

5-fluorouracil is known to quell cancer because it inhibits cell division. But the drug is also more effective against colorectal cancer than other types of cancer, and this could be due to its ability to kill too Fusobacteriathe researchers speculated.

“The results show that intratumor microbes are not innocent bystanders during disease progression and suggest that the microbiota should be considered when thinking about optimal cancer treatments,” said Fred Hutch assistant professor Christopher Johnston in a post by Fred Hutch on the new studios. Johnston led the research together with Fred Hutch assistant professor Susan Bullman.

The new studies could be relevant to other types of cancer.

Until a few years ago, tumors were thought to be sterile. But more recently, bacteria have been detected in a variety of tumor types.

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