Two studies recently published in the Journal of the National Cancer Institute offer new ways to limit the growth of breast cancer tumors.
The first study, conducted by Dr. Andrew W. Cuthbert and colleagues at Brunel University in Uxbridge, U.K., found that adding human chromosome 3 to a line of breast cancer cells brought growth of the cells to a complete halt. Given these impressive results, researchers will now begin searching for anti-cancer drugs that can produce the same effect.
Cancer cells differ from normal cells in that they have no limits on cell growth, and continue to divide and grow indefinitely. An enzyme named telomerase is at least partly responsible for cancer cells’ unending growth. By adding human chromosome 3 to the breast cancer cells, researchers were able to decrease the activity of telomerase by 98%.
A second study concerned breast cancer cells that have become resistant to the tamoxifen, a drug that blocks the growth-promoting effects of estrogen and can be used to treat 40%-60% of all breast cancers. Researchers at Vanderbilt University found that they could improve tamoxifen’s ability to fight the seemingly drug-resistant cells by blocking a growth factor called TGF-b.
In a study of mice, researchers found that an anti-body to TGF-b increased tamoxifen’s ability to fight breast cancer cells. However, a test of tamoxifen-resistant breast cancer cells in culture dishes did not produce the same results.
Lead study author Dr. Carlos Arteaga noted, “The most important finding is that by blocking something produced by the tumor cells — that can be measured in some of these tumor tissues and that can be interfered with by strategies in preclinical development — we can enhance tamoxifen action, which is again, a relatively nontoxic, widely available agent with a proven track record against breast cancer.”