Cloning experiment shows cancer reversible

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Cloning experiment shows cancer reversible

 

Study finds cancer genes can be turned on and off

 

WASHINGTON - A cloning experiment may show that the body itself has the

ability to reverse cancer, U.S.-based researchers said Saturday.

 

They cloned mouse embryos from a melanoma skin cancer cell, and created

healthy adult mice using some of the cloned cancer cells, showing that

malignancy is not the inevitable fate of a cancer cell.

 

" This settles a principal biological question, " said Dr. Rudolf Jaenisch

of the Whitehead Institute at the Massachusetts Institute of Technology,

one of the country's leading experts in cloning.

He said while the genetic elements of cancer cannot be reversed, the

epigenetics -- how the genes are actually turned on and off -- can be.

 

The finding, published in the journal Genes and Development, point to a

new way to treat cancer, said Lynda Chin of the Dana-Farber Cancer

Institute and Harvard Medical School, who worked on the study.

 

" Drugs that target the cancer epigenome may prove to be a key

therapeutic opportunity for diverse cancers, " she said in a statement.

In other words, it might be possible to silence a cancer gene.

 

Cancer begins when certain genes mutate, or when a certain, inherited

version of a gene somehow gets turned on.

 

This can happen through various so-called epigenetic processes -- when

other molecules in a cell affect genes without actually altering the

sequence of DNA.

 

Embryonic stem cells used

In the experiment, Konrad Hochedlinger and Robert Blelloch, both

researchers in Jaenisch's lab, took the nucleus from a melanoma cell and

injected it into a hollowed-out mouse egg cell.

 

This started the egg growing as if it had been fertilized by sperm.

 

They did not allow this embryonic mouse to develop, but harvested from

it embryonic stem cells -- immature cells that have the potential to

become any cell in the body at all.

 

They put these stem cells into healthy mouse blastocysts -- very early

embryos only a few days old. Some of these developed into healthy,

normal mice.

" It's important to note that the stem cells from the cloned melanoma

were incorporated into most, if not all, tissues of adult mice, showing

that they can develop into normal, healthy cells, " Blelloch said.

 

They included skin pigmentation cells, immune cells and connective

tissue.

This could only have happened if the cancer cells had lost their

malignant qualities, at least temporarily, the researchers said.

 

But when certain cancer-related genes in these mice were activated, they

developed malignant tumors at a much faster rate than normal mice, the

researchers added.

 

Many researchers want to try similar experiments with human cancer

cells, but the administration of President Bush forbids the use of

federal funds for such study because it would involve the creation of

what is technically a human embryo.