A question worth answering: why don’t cancer cells die?

When cells become cancerous, they grow unrestrained and sometimes ignore signals that would normally induce them to die. “What are the genetic functions,” Nobel laureate Harold E. Varmus, M.D., asked in a November 1 campus talk, “responsible for sustaining the life of cancer cells?” Varmus, president and chief executive officer of Memorial Sloan-Kettering Cancer Center and the former director of the National Institutes of Health, gave the keynote address at the 2002 Graduate Student Research Symposium, an annual event that brings speakers to campus and provides graduate students a venue for presenting research in progress.

In his address Varmus described how his laboratory has used new ways to study those genetic functions in mouse models of lung and ovarian cancers. Varmus and colleagues controlled expression of a mutant gene by dosing mice with the antibiotic doxycycline: in this way they could induce lung cells to become cancerous. Halting the drug dosages abruptly reduced the expression of that gene, K-ras, and triggered the death of the tumor cells, causing the cancers to melt away.

His laboratory is attempting to understand how genes like K-ras “protect cells from cell death” and what happens when the cells lose K-ras function and die. From there, the goal will be to figure out “how to trigger a similar response in humans,” which, Varmus suggested, could prove key to developing new treatments for the deadly cancers.

—Marc Wortman

A disheartening view of AIDS in South Africa

“I will give you a picture that will sound a bit bleak,” Maria C. Marchetti-Mercer, Ph.D., told an audience at a lunch sponsored by the Center for Interdisciplinary Research on AIDS in September. Marchetti-Mercer, head of the department of psychology at the University of Pretoria in South Africa, proceeded to paint a landscape of social and political turmoil and its relationship to the growing HIV/AIDS pandemic. With the end of apartheid in the 1990s, political violence gave way to criminal and domestic violence. The country has seen increasing incidents of “family murder,” the killing of all family members by a parent. Added to this mix is the impact of HIV/AIDS, which is estimated to have left at least 660,000 orphans and reduced families to poverty as breadwinners die or become incapacitated.

“Poverty doesn’t cause AIDS,” Marchetti-Mercer said. “But it does create a context where people are more vulnerable.”

People with HIV/AIDS are stigmatized, and society offers little in the way of social, economic or psychological support. As a result, Marchetti-Mercer said, poverty and crime will only increase. “I think we are moving toward another lost generation,” she said, referring to the orphans the epidemic has left. “This whole cycle of poverty and criminal and domestic violence will go on because of the impact of HIV/AIDS.”

—John Curtis

African dust brings nutrients—and toxins

For centuries winds have carried dust from Africa and deposited it on islands in the Caribbean and locations in Florida and South America. The dust provides essential nutrients to the upper canopy of the Amazon rain forest and, in the Bahamas, contributes to the formation of red soils known as pineapple loam.

As early as 1846, however, Charles Darwin was complaining about the pernicious effects of African dust as he traveled through the Canary Islands. In recent years the dust has carried traces of fertilizers, pesticides, mercury, arsenic, bacteria and a fungus called Aspergillus that has devastated sea fans on Caribbean coral reefs.

According to Eugene A. Shinn, Ph.D., a geologist with the U.S. Geological Survey in St. Petersburg, Fla., the dust also has implications for human health. “It causes lung infections,” Shinn told students at the School of Forestry & Environmental Studies in November. He also believes African dust is linked to increases in asthma throughout the Caribbean.

Since the 1970s deforestation and drought in Africa have caused huge dust storms. When they reached the Caribbean, the effects were obvious. “In San Juan, Puerto Rico, people could feel it in their chests. They had headaches,” Shinn said.

Shinn is working with microbiologists and physicians to study the problem, but as he cautioned at the start of his lecture, “This is a bad-news/bad-news story.”

—John Curtis

In history of birth control, a male influence

Although birth control is widely viewed as a women’s issue, men have played a large, if unrecognized, role in reproductive rights, Andrea Tone, Ph.D., professor of history at the Georgia Institute of Technology, said at a History of Medicine and Science lecture in December. “If you examine sources not usually considered vital to the history of birth control—arrest records, credit reports, trial transcripts, patent applications, post office records, military investigations, FTC and FDA records and men’s letters—you encounter a cast of characters who are not only fundamental to the history of modern contraception, but who are also often men,” said Tone, author of Devices and Desires, a history of contraception from 1873 to 1973.

Among those men was Julius Schmid, who, in 1883, found a use for animal intestines beyond making sausages. He did what Europeans had been doing since the Renaissance and turned the delicate but impermeable membranes into condoms. To skirt laws against such devices, condoms and diaphragms were marketed as “French goods and medicines.”

Late-19th-century physicians favored condoms as an effective means of birth control. And, letters of that time reveal, contraception was on the minds of husbands as well as wives. “Men discussed how anxious they were to protect their wives’ health and welfare from the toll of uninterrupted childbearing,” Tone said, “and they worried how they, as breadwinners, could afford to feed another mouth.”

—John Curtis