Oxidative Stress Kept at Bay from Cancer Cells by Protein

Thioredoxin-like 2, a protein, keeps cancer cells from the oxidative stress that results from their growth and invade tissues throughout the body, reported researchers.

When Dr. Ning-Hui Cheng, an instructor at the USDA/ARS Children's Nutrition Research Center at Baylor College of Medicine and Texas Children's Hospital, and his colleague Dr. Xiaojiang Cui (then at BCM and now at the John Wayne Cancer Institute in Santa Monica, Calif.) looked for the protein in human breast cancer cells, they found it exists there at high levels.

Clinical Trials | Drug Trials - Types Protocol Development and Approval FAQs
Clinical trials are experiments that yield useful information to clinicians if a particular treatment is of any value to a patient.

When they removed the protein from the cancer cells, the levels of oxidative stress (called reactive oxygen species or ROS) increased and an important signaling activity called NF-kB were reduced. As a result, the cells ceased growing and invading.

"They did not thrive. Cancer cells can use this as a weapon to keep oxidative stress at a level that is toxic to normal cells but can be tolerated by cancer cells," he said. This ability to withstand oxidative stress is one reason cancer cells can resist anti-cancer drugs, he said.

"Our data show that this protein is highly expressed in cancer cells lines and in patients," he said.

Clinical Trials and Its different Phases
Clinical trials serve as a vital component for improving the treatment of medical conditions as they lead to higher standards of patient care.

This makes thioredoxin-like 2 (also called glutaredoxin 3) a promising target of future drug development, said Cheng.

"We could use an inhibitor to reduce the levels of the protective protein. When the reactive oxygen species levels go up, it kills the cancer," he said. He thinks this protein plays an important role in the spread of cancer or metastasis.

Treatment Effects Often Exaggerated by Stopping Clinical Trials Early
Nearly 100 clinical trials were stopped early due to positive treatment effects, which may actually have been exaggerated, says a new study.

The protein is essential for normal growth in developmental stages, he said. Mice bred to lack this protein die before birth.

"Cells that lack this protein cannot survive," he said. "The difference is that cancer cells produce too much and they survive as well.

He and his colleagues have found high levels of protein in other cancers as well. In future studies, they hope to find out whether the protein causes cancer or just maintains it.

Source-Eurekalert