A "vicious cycle" produces mucus that protects uterine and pancreatic cancer
cells and promotes their proliferation, U.S. researchers say.
Biochemist Daniel Carson, dean of Rice University's Wiess School of Natural
Sciences; lead author Neeraja Dharmaraj, a postdoctoral researcher; and graduate
student Brian Engel found that protein receptors on the surface of cancer cells
go into overdrive to stimulate the production of MUC1, a glycoprotein that forms
mucin, or mucus.
Mucus covers the exposed tips of the elongated epithelial cells that coat
internal organs like lungs, stomachs and intestines to protect them from
infection, the researchers said.
However, when associated with cancer cells, the slippery agents of mucus do
their jobs too well. They cover the cells completely, help them metastasize and
protect them from attack by chemotherapy and the immune system, the study said.
Carson compared mucus to Teflon. "Things don't stick to it easily, which is
normally what you want. It's a primary barrier that keeps nasty stuff like
pathogenic bacteria and viruses from getting into your cells," Carson said in a
statement. But cancer cells "subvert systems and find ways to get out of
Hope comes in the form of a controversial drug, rosiglitazone, in the
thiazolidinedione class of medications used in diabetes treatment, he said.
The drug is suspected of causing heart problems over long-term use by diabetes
patients, but tests on cancer cell lines at Rice found it could provide a way to
weaken the mucus shield.
"Chronic use of rosiglitazone can produce heart problems in a subset of
patients, but if you're dying of pancreatic cancer, you're not worried about the
long term," Carson said. "If you can reduce mucin levels in just a few days by
using these drugs, they might make cancer cells easier to kill by established