• By Susan Murphy

Science Saturday: Uterine microbe found to have disease-causing behavior in endometrial cancer

September 4, 2021

A tiny microbe thriving in the uterine microbiome — a population of bacteria, viruses, yeasts/fungi in and around the uterus— could be a contributing driver of endometrial cancer, according to a new Mayo Clinic study. 

"We have found that a microbe that is particularly associated with endometrial cancer is capable of pathogenic behavior, and is stimulated by one of the main risk factors for the disease — estrogen exposure," explains Marina Walther-Antonio, Ph.D.,  a researcher within the Mayo Clinic Center for Individualized Medicine who focuses on the human microbiome's role in women's health, in particular gynecologic cancers. 

The study, published in Frontiers in Microbiology, is the third recent investigation by Dr. Walther Antonio and her team that links the microbiome to endometrial cancer — the most common cancer in women, with nearly 66,000 new cases and nearly 13,000 deaths estimated in 2020. Incidence rates are expected to rise significantly over the next decade, driven by environmental factors, obesity and diabetes.

Zeroing in on a tiny predator

For the study, the multidisciplinary team exposed endometrial cancer cells to the microbe called Porphyromonas somerae, a rod-shaped bacterium nearly 1,000 times smaller than a pin. The microbe was initially discovered in chronic bone and tissue wounds of patients with diabetes.

Given the known associations of the microbe's closest relative to oral cancer, the team hypothesized that Porphyromonas somerae could invade and may play a similar pathogenic role in endometrial cancer via intracellular activity. 

"Through multiple lines of investigation, including invasion assays, microscopy, genomic and transcriptomic analysis, we verified that the microbe was capable of disease-causing behavior and would indeed invade the cells," Dr. Walther-Antonio explains.

Dr. Walther Antonio's investigation techniques:

  • An invasion test consists of exposing the bacteria to an antibiotic that they are sensitive to while in the presence of host cells.
  • microscopy shows imaging of bacteria attached or inside the host cells.
  • Genomic data can reveal if the bacteria has the genes necessary for invasive and virulent behavior.
  • Transcriptomic data can disclose if the bacteria are able to express the genes necessary for invasive behavior.

"The single-cell data allowed us to find the elements of interest with ease," Dr. Walther Antonio says. "This would have been difficult to achieve with population-level approaches," she says.

Read more on the Center for Individualized Medicine blog.

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