Bladder Cancer

HOPKINS SCIENTISTS FIND CELLS RESPONSIBLE FOR BLADDER CANCER’S SPREAD

Powerful cells located in same tissue location as bladder stem cells

Aug. 6, 2009 – Johns Hopkins scientists have tracked down a powerful set of cells in bladder tumors that seem to be primarily responsible for the cancer’s growth and spread using a technique that takes advantage of similarities between tumor and organ growth. The findings, reported in the July Stem Cells, could help scientists develop new ways of finding and attacking similar cells in other types of cancer.

Researchers have long suspected that a subset of cells in cancerous tumors act much like developmentally primitive cells known as stem cells, which spur organ development early in life and remain present in nearly all the body’s organs to repair or replace injured and aging tissues. These cancer cells and stem cells share a variety of characteristics including an unlimited lifespan and a propensity to migrate through tissues.

These same properties are the ones that make cancer particularly dangerous, says David Berman, M.D., Ph.D., associate professor of pathology, oncology, and urology at the Johns Hopkins University School of Medicine. If researchers had a way to identify and specifically target cancer cells with these properties, they could wipe out the population that sustains tumors and makes them grow.

Other researchers have identified proteins on the surfaces of these cancer cells that could work as markers, but because other cells sometimes shared these proteins, this approach can lead to errors, Berman says.

In the new study, led by Berman’s postdoctoral research fellow Xiaobing He, Ph.D., the researchers reasoned that if these stem-like cancer cells behave like healthy stem cells, they might be physically located in the same compartments in tissue where stem cells normally reside. Using a surface protein marker previously identified for healthy bladder stem cells, the Hopkins team searched for cells with the same marker in sections from 55 human bladder tumors. They found that cancer cells displaying the marker were localized in an area at the intersection of two layers of cells known as epithelium and stroma, the place where bladder stem cells are typically located.

Using cancer cell lines grown from other bladder cancer patients, the researchers separated cells displaying the stem cell marker from those without it and injected these two populations into different sets of mice. Mice injected with the cancer cells displaying the marker always grew tumors, but those injected with the other cancer cells rarely did, suggesting that the stem-like cancer cells have an ability to create new tissue much like healthy stem cells do.

When the researchers surveyed both cancer cell populations to see which of their genes were most active, they found that genes with roles that are well-known hallmarks of cancer, such as cell proliferation and metastasis, were significantly more active in the stem-like cells than in the other cancer cells. Genes known to help cancers survive chemotherapy and radiation were also more active in the stem-like cells.

Other researchers who participated in this study include Luigi Marchionni, Wayne Yu, Akshay Sood, Jie Yang, Giovanni Parmigiani, and William Matsui, all of Johns Hopkins; and Donna E. Hansel of the Cleveland Clinic.

For more information, go to:

http://urology.jhu.edu/index.html

http://urology.jhu.edu/about/faculty.php?id=69

http://pathology.jhu.edu/berman/

Media Contact:
Christen Brownlee, 410-955-7832; cbrownlee@jhmi.edu

Bladder cancer will affect over 60,000 patients in 2009.  Although being diagnosed with such a disease no doubt effect an emotional and physical toll on afflicted patients., I would like to highlight some ameliorating facts and point to opportunities in fighting this disease.

Bladder cancer is best looked at as two diseases rather than one: A “superficial” disease and a “deep” disease.  The superficial one can lead to recurrences and in a minority of cases will lead to progression into deep disease. Frequent follow-ups and urine cytology examination will help identify early recurrences and hopefully prevent progression in patients with superficial disease.

Research opportunities in the superficial type of bladder cancer reside in finding markers that will help us better identify which lesions are more likely to progress. By identifying such markers of early recurrence and high risk of progression, one can then limit intense follow up efforts to high risk patients while extending intervals between doctor visits and cystoscopies in low risk patients.

Next time will talk about challanges and opportunities in the more aggressive “deep” disease category of bladder cancer.

By Dr. David Berman

What would the cure for cancer look like? My hope is that it would look a lot like the cure for strep throat — a pill that a patient would take for a few days to wipe out the offending invaders while leaving the rest of the body unharmed. To get to this Utopian place, cancer treatment will need to adopt several strategies from the battle against infectious disease, including:

1. Exploit biological differences between the invader (cancer cell) and the host (the patient).
2. Develop laboratory tests to determine which drugs are useful for a given individual’s disease (personalized therapy).
3. Simultaneously attack multiple molecular targets so that if one attack fails, the others can still win the war.