New gene identified in breast cancer

Researchers at McMaster University and McGill University have identified a
new player in breast cancer. This gene, beta1-integrin, has been shown to be
critical in the initiation of tumour growth and development in a mouse model
of cancer.

“We are the first to demonstrate the requirement for beta1-integrin in
the induction of breast cancer in genetically engineered mice,” says senior
author William
Muller, formerly of McMaster and now a professor of medicine and biochemistry
at McGill. “Our findings show that blocking the function of this gene
halts tumour proliferation. We also show that in our model of breast cancer,
tumour cells do not grow without beta1-intergrin. These results demonstrate
the importance of this gene in tumour biology. The next step is to look for
therapeutics which block this gene in humans.”

Professor John
Hassell and graduate students Natasza Kurpios and Don White, of McMaster's
Department of Biochemistry and
Biomedical Sciences, used breast-cancer prone mice to demonstrate the role
of beta1-integrin. They initially showed that removing this gene did not affect
the normal mammary development of the mice. They then went on to show that if
this gene was removed from already growing tumours, the tumours would cease
to grow.

“The way we did this was to remove the breast tumor from the transgenic
mouse in which the tumor first arose,” said Hassell. “We isolated
the tumor cells comprising the tumor, grew the cells in a Petri dish in the
lab, infected the cells with a virus that targets the beta-1 gene for inactivation,
and then transplanted the cells into the mammary gland of a normal mouse to
learn whether tumors developed. Natasza Kurpios did all the cell transplants
and cell manipulations here at Mac.”

Don White, first author of the study and a graduate student defending his thesis
at McMaster this week, said: “This is an exciting time in breast cancer
research. The more players we identify, the more likely we are to cure this
disease.”

These findings are published in the August 23, issue of Cancer Cell
and are currently available online at www.cancercell.org
.

This research was funded by the Canadian
Breast Cancer Research Alliance (CBCRA) and National
Cancer Institute.