How exposure to social stress early in life ups breast cancer risk

Washington, June 19 (ANI): Local chemical signals released by fat cells in the mammary gland appear to provide a crucial link between exposure to unrelenting social stressors early in life, and the subsequent development of breast cancer, according to researchers from the University of Chicago.

Some forms of stress exposure may be associated with an increased risk of certain types of aggressive breast cancer. But the mechanisms linking the biology of social stress to cancer have been hard to identify.

To unravel that mechanism, the researchers looked for differences between mice raised in small groups and those that grow up in an isolated setting-an established model of chronic stress without social supports.

"We found that exposure to the stress of social isolation leads to reprogramming of genes in fat cells in the mammary glands. These fat cells then secrete substances that cause nearby pre-cancerous epithelial cells to proliferate more rapidly, accelerating the development of breast cancer. This local effect of fat cells in the breast was completely unanticipated," said study author Suzanne Conzen, MD, professor of medicine at the University of Chicago.

The researchers used a genetically altered mouse model of "triple-negative" breast cancer-a form of the disease that lacks receptors for estrogen, progesterone and HER2, three important treatment targets in humans. Triple-negative cancer, representing about 15 percent of all breast cancers, appears to occur disproportionately in younger women. In this mouse model, animals develop precancerous changes in mammary epithelial cells that later lead to cancer.

The mice tested-known as SV40-T antigen mice-all develop tumors by about 16 weeks of age. The researchers previously showed that female mice raised in isolation develop significantly larger, more aggressive, triple negative tumors, and wanted to understand the detailed biology underlying this observation.

Conzen worked closely with colleague Martha McClintock, PhD, professor of psychology at the University of Chicago, to carefully model chronic social stress exposure in female mice. In previous joint projects they showed that a measurable chronic stress response could reliably be induced in mice by raising them in isolation after weaning, rather than housing them in small groups.

In this study, Conzen also worked with colleague, Matthew Brady, PhD, associate professor of medicine and a specialist in fat cell biology, to decipher the effect of stress on the mammary fat.

The researchers looked for differences in gene expression in multiple tissues and circulating hormones between group-housed and isolated mice. To their surprise, there were no significant differences in circulating hormones.

They found a dramatic change, however, in fat cells located within mammary glands. Measurements of those cells taken at 15 weeks of age showed that social isolation stimulated significant increases in the expression of three genes-Hk2 (hexokinase), Acly (ATP citrate lyase) and Acaca (acetyl-CoA carboxykase).

Why is breast fat particularly sensitive to the effects of social isolation? Scientists don't yet understand how this response fits into the larger picture of the deleterious effects of stress on an organism, but "it will be an important avenue to pursue, particularly when so much human disease appears to be negatively impacted by social stressors, diet, and other factors causing metabolic derangement," Conzen said.

The researchers reported their finding in the July 2013 issue of the journal Cancer Prevention Research. (ANI)

Matches

MORE TOP STORIES TODAY

Delhi Daredevils vs Royal Challengers Bangalore

Delhi Daredevils vs Royal Challengers Bangalore

Kohli wins the toss and puts Delhi into bat. Chris Gayle MISSES OUT!!! More »

Kallis, Narine star in Knight Riders’ crushing win

Kallis, Narine star in Knight Riders’ crushing win

An all-round display saw Knight Riders thump Mumbai Indians by 41 runs in the IPL-7 opener. More »

Gavaskar wants a clean IPL

Gavaskar wants a clean IPL

"Integrity is non-negotiable..." says the BCCI's interim chief ahead of Season 7 of the tainted league. More »

'Yak' Kallis still on top of his game

'Yak' Kallis still on top of his game

The 38-year-old South African veteran turned it on for Kolkata Knight RIders in the opening match of IPL-7. More »

Srinivasan named in fixing report: SC

Srinivasan named in fixing report: SC

The court emphasised that the tainted administrator can no longer work for the BCCI. More »

Yuvraj happy to play for RCB: Kohli

Yuvraj happy to play for RCB: Kohli

New-look RCB will play their first game of IPL-7 on Thursday. More »

IPL: News Line

IPL: News Line

A round-up of all the news from this season of the IPL. More »

Shane Watson issues moral warning

Shane Watson issues moral warning

'Everyone knows what is right and what is wrong and if you do the wrong thing it will be found out' More »

Why I'm not looking forward to the IPL

Why I'm not looking forward to the IPL

Welcome to another season of a league that many watch but few trust. More »

Nepal players call off boycott

Nepal players call off boycott

Thaw in relations after formation of an advisory committee that would work in tandem with the Cricket Association of Nepal. More »

Johnson may quit T20s for Tests

Johnson may quit T20s for Tests

Australia's Mitchell Johnson may quit limited-overs cricket to prolong his test career with an eye on the 2015 Ashes series in England, the fast bowler… More »

There's a lot going on: Fleming

There's a lot going on: Fleming

He experienced anxious moments in the lead-up to the tournament as the courts decided on whether to suspend the franchise, he said, but stressed that the… More »

Latif couldn’t work with tainted players

Latif couldn’t work with tainted players

Former Pakistan cricket captain Rashid Latif said Tuesday he turned down the job of national chief selector because he could not work with ex-players tainted… More »

We are not over-confident: Bailey

We are not over-confident: Bailey

Indian Premier League — George Bailey-led Kings XI Punjab will face Chennai Super Kings on Friday. More »

Big runs expected, with bat and ball

Big runs expected, with bat and ball

Royal Challengers Bangalore: Their main concern, once again, is the fast bowling More »

Taxing issue — BCCI hits roadblock

Taxing issue — BCCI hits roadblock

MoU between BCCI & its units to avoid double taxation delayed after a few decline to share details. More »

Black Caps pick rookie duo for West Indies

Black Caps pick rookie duo for West Indies

New Zealand selectors included two new caps in a 15-man Test squad named Tuesday to tour the West Indies, with injury-hit spinner Dan Vettori's future… More »

The stage is set for IPL-7 to start

The stage is set for IPL-7 to start

The Preview — Defending champions Mumbai Indians take on Kolkata Knight Riders More »

Srinivasan appeals to court to allow BCCI comeback

Srinivasan appeals to court to allow BCCI comeback

He was aggrieved by the allegations against him during the hearing. More »

Klinger on his exit from South Australia

Klinger on his exit from South Australia

Michael Klinger has revealed he felt compelled to leave South Australia after being told he would be only a fringe part of the Redbacks' plans for next season, and disputed the suggestion that he left… More »

India: cricket's Brazil

India: cricket's Brazil

They are tough to beat with a big talent base exposed to good facilities. (CYCSPL) More »

Delhi Daredevils say no to gifts

Delhi Daredevils say no to gifts

Franchises are doing their bit to refurbish the image of the tainted league. More »

India-Pakistan Test series likely in 2015

India-Pakistan Test series likely in 2015

The revival of Indo-Pak Test ties could take place in UAE. More »

Kohli hopes to end RCB trophy drought

Kohli hopes to end RCB trophy drought

'This time around we will hope to go few more steps ahead and actually get that trophy' More »