According to a study from Duke Cancer Institute, a drug, originally approved to help treat patients suffering from osteoporosis, may also aid in reducing the growth of breast cancer cells, even those cells that have become resistant after application of many therapies.
This drug - bazedoxifene - prevents growth of breast cancer cells by lowering down estrogen levels, and aiding the production of estrogen receptor that is meant for the destruction of breast cancer cells.
"We found bazedoxifene binds to the estrogen receptor and interferes with its activity, but the surprising thing we then found was that it also degrades the receptor; it gets rid of it," Donald McDonnell, PhD, chairperson of the Duke's Department of Pharmacology and Cancer Biology and senior author of the study, explained.
Using animal subjects and cell culture studies, the researchers studied how the drug managed to do both- treat osteoporosis ad inhibit the growth of breast cancer cells.
Today, if breast cancer cells develop a resistance to conventional drug therapies like aromatase inhibitors, anti-estrogen tamoxifen and other drugs, they are usually treated using toxic chemotherapy- a treatment that has profound side effects on the individual undergoing the therapy.
This drug - Bazedoxifene belongs to a class of drugs known as specific estrogen receptor modulators (SERMs), just like tamoxifen. However, Bazedoxifene has an upper hand given its ability to behave similar to estrogen in some particular tissues of the body, and blocking the actions linked to estrogen production in some tissues. It also managed to target the estrogen receptor for destruction, thus demonstrating its properties similar to those of a newer group of drugs- SERMs.
"Because the drug is removing the estrogen receptor as a target by degradation, it is less likely the cancer cell can develop a resistance mechanism because you are removing the target," lead author Suzanne Wardell, claimed.
Once the breast cancer cells developed a resistance to the drug tamoxifen, they would reject all forms of treatment, expect for those that target the estrogen receptor.
The study researchers tested the drug on a variety of breast cancer cells- tamoxifen sensitive cells, advanced breast cancer cells, and cancer cells containing the mutant HER2 gene. All these cancer cells had demonstrated reactivation of estrogen signaling to develop drug resistance. But when bazedoxifene was introduced, it managed to inhibit cell growth.
The researchers further report that the working of this very drug seems to be paradoxical in nature, given that it aids the destruction of cancer cells, and prevents the destruction of bone cells.
Further studies may confirm if this drug doesn't have any side effects and if it may be suited for human use.