The making and unmaking of stem-like, aggressive breast cancer cells

August 9, 2012

Breast cancers that depend on the hormones estrogen and progesterone are susceptible to treatments targeting these hormones. Take away this dependence and you lose a valuable treatment option.

A University of Colorado Cancer Center study published as a featured article in the journal Oncogene shows how does just this – by suppressing a key microRNA, progestins return cells to a stem-cell-like state in which they haven't yet differentiated, and are thus more resistant to chemotherapies and more likely to carry a poor prognosis.

"The reason we were looking into the possible role of microRNAs in the dedifferentiation of breast into this aggressive, chemo-resistant phenotype is that microRNAs tend to be good, druggable targets. Because one microRNA may regulate many genes involved in a cancerous signaling pathway, we hoped to find one target with many beneficial effects," says Diana Cittelly, PhD, postdoctoral fellow at the CU Cancer Center and the paper's first author. The study was a collaboration between the CU Cancer Center labs of Jennifer Richer, PhD, and Carol Sartorius, PhD.

Specifically, the study shows that progestins regulate miRNA-29 – a molecule that helps to decide which of a cell's genes are and are not turned into proteins. This regulation of miRNA-29 creates a cascade that stimulates breast cancer cells to revert back to a stem-like state, marked by proteins CD44 and CK5. In animal models, these stem-like cells helped breast cancer evolve around the blockages of current treatments..

"We can manipulate this miRNA-29 in cell lines," Cittelly says, "and we hope technology isn't too far in the future that will allow us to deliver miRNA-29 in human cancers as well."

Turn off the role of miRNA-29 and the hope is that breast cancers won't be able to gain stem cell-like traits and lose their dependence.

Explore further: Heterogeneous ER+ breast cancer models allow more accurate drug testing

Related Stories

Heterogeneous ER+ breast cancer models allow more accurate drug testing

August 6, 2012
(Medical Xpress) -- Cell cultures are homogeneous. Human tumors are not. A University of Colorado Cancer Center study recently published in the journal Breast Cancer Research and Treatment reports the development of human-derived ...

New target, new drug in breast cancer

June 4, 2012
Many breast cancers depend on hormones including estrogen or progesterone for their survival and proliferation. Eight years of lab work at the University of Colorado Cancer Center and elsewhere suggest that the androgen (AR) ...

Recommended for you

Shooting the achilles heel of nervous system cancers

July 20, 2017
Virtually all cancer treatments used today also damage normal cells, causing the toxic side effects associated with cancer treatment. A cooperative research team led by researchers at Dartmouth's Norris Cotton Cancer Center ...

Molecular changes with age in normal breast tissue are linked to cancer-related changes

July 20, 2017
Several known factors are associated with a higher risk of breast cancer including increasing age, being overweight after menopause, alcohol intake, and family history. However, the underlying biologic mechanisms through ...

Immune-cell numbers predict response to combination immunotherapy in melanoma

July 20, 2017
Whether a melanoma patient will better respond to a single immunotherapy drug or two in combination depends on the abundance of certain white blood cells within their tumors, according to a new study conducted by UC San Francisco ...

Discovery could lead to better results for patients undergoing radiation

July 19, 2017
More than half of cancer patients undergo radiotherapy, in which high doses of radiation are aimed at diseased tissue to kill cancer cells. But due to a phenomenon known as radiation-induced bystander effect (RIBE), in which ...

Definitive genomic study reveals alterations driving most medulloblastoma brain tumors

July 19, 2017
The most comprehensive analysis yet of medulloblastoma has identified genomic changes responsible for more than 75 percent of the brain tumors, including two new suspected cancer genes that were found exclusively in the least ...

Novel CRISPR-Cas9 screening enables discovery of new targets to aid cancer immunotherapy

July 19, 2017
A novel screening method developed by a team at Dana-Farber/Boston Children's Cancer and Blood Disorders Center—using CRISPR-Cas9 genome editing technology to test the function of thousands of tumor genes in mice—has ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.