Normal Embryos from Cancer Cells

Science Watch

PureInsight | June 16, 2003

[] MEMPHIS, TENN. (June 3, 2003) -- Nuclei removed from mouse brain tumor cells and transplanted into mouse eggs whose own nuclei have been removed, give rise to cloned embryos with normal tissues, even though the mutations causing the cancer are still present. This research, from scientists at St. Jude Children's Research Hospital, appears in the June 1 issue of Cancer Research.

The finding demonstrates that the cancerous state can be reversed by reprogramming the genetic material underlying the cancer, according to James Morgan, Ph.D., a member of the St. Jude Department of Developmental Neurobiology, and lead author of the study. The findings also indicate that genetic mutations alone are not always sufficient to cause a cell to become cancerous.

"Specifically, it shows that so-called epigenetic factors are key elements in the development and maintenance of tumors," Morgan said.

Epigenetic factors are those that influence the cell's behavior. Examples include environmental effects and chemical modification.

"The concept of epigenetic factors having a role in cancer is already largely accepted," Morgan said. "In fact, it's already known that epigenetic alterations of chromosomes can cause certain rare forms of cancer. And some anti-cancer agents actually target epigenetic changes. But this is the first formal proof of the theory in a living animal."

Unlike mutations, epigenetic modifications of DNA are potentially reversible molecular events that cause changes in gene expression. Some genes that help prevent the development of cancer (e.g., tumor suppressor genes) can be targets of epigenetic factors. The inactivation of such a gene might make the DNA more vulnerable to developing a cancer-causing mutation.

These scientists think that the use of a system like this to reprogram cellular DNA represents a new strategy for investigating the molecular basis of cancer and, eventually, other diseases thought to have a genetic causal component. In addition, it might also provide a valuable tool for testing new therapies. It is clear, however, that a person's genetic makeup is not the sole determinant of whether he will be healthy or ill. These are only superficial manifestations seem in this dimension. As we know that the true causes of disease and recovery from it do not lie in this dimension, it is interesting to encounter evidence that displays the discordance between conventionally accepted "causes" of events and the events themselves. Besides the complex interplay of biological factors, alluded to above as epigenetic factors, more and more studies also relate one's well-being to one's internal environment, especially including one's mental and moral states.


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