According to University of Texas, after being caught in DNA ‘webs’ extruded by immune cells, ovarian cancer metastasis occurs, spreading to new tissue.
Researchers from the University of Texas MD Anderson Cancer Center, USA, have discovered that ovarian cancer cells spread, or metastasize, to new tissue after being caught in the DNA ‘webs’ that are forced out by immune cells. The study, reveals that preventing immune cells from forming these webs reduces metastasis in mice, suggesting that similar treatments could be used to limit the occurrence of ovarian cancer metastasis in humans.
Ovarian cancer metastasis
Ovarian cancer is the fifth leading cause of cancer death in women.
Advanced stages of the disease are typically characterised by the spread of cancer cells to the omentum, a fatty tissue that drapes from the stomach, due to its role in housing immune cells that can fight off infections in the abdominal cavity.
The reasons as to why and how ovarian cancer cells preferentially spread to this tissue is unclear.
The accumulation of unwanted cells
The researchers discovered that, at early stages of ovarian cancer, immune cells called neutrophils accumulate in the omentum and begin to unwind and extrude their DNA in the form of sticky webs.
These webs, known as neutrophil extracellular traps (NETs), are normally used to entrap invading microbes. But the researchers found that NETs can also entrap circulating ovarian cancer cells, allowing them to colonise the omentum, therefore causing ovarian cancer metastasis to occur.
Dr. Honami Naora at the University of Texas explains: “Our study demonstrates that inhibiting NET formation decreases omental metastasis.”
Naora’s team essentially determined that ovarian cancer cells release proinflammatory molecules that cause neutrophils to accumulate in the omentum and deploy their NETs.
However, when the researchers prevented NET extrusion by inhibiting a key enzyme required for the process, they reduced the ability of ovarian cancer cells to spread to the omentum in mice.
Currently, the omentum is often surgically removed from patients with early-stage ovarian cancer in an attempt to limit ovarian cancer metastasis to spread further.
But Naora and colleagues suggest that inhibiting NET formation could prevent ovarian cancer metastasis while maintaining the omentum’s protective function within the abdomen.
Naora concludes: “Further studies of this intriguing host defence mechanism could yield new insights into improving ovarian cancer treatment.”