Cancer Study Nears Possible Breakthrough

By inducing cells to "commit suicide," a Harvard Medical School researcher has stated he may develop a treatment for two, and possibly three, forms of cancer by the end of the year.

Dr. Michael M. Wick '66, research fellow in Dermatology, reported in the February 17 issue of Science magazine that a form of L-dopa--a molecule stored and used by some body cells that sometimes turn cancerous--is effective against such cancerous cells.

Wick said in an interview last week that, "The next step is man." he added that he hopes to complete studies of the effects of L-dopa methyl ester on the human forms of some cancers, including leukemia, by the end of the summer.

"We're not saying it's a cure," Wick said, but he added that L-dopa could be used with other agents in chemotherapy.

The Science article is Wick's third report in a year on his research. Wick earlier demonstrated the toxicity of the more soluble methyl ester form of L-dopa on forms of mouse cancer.

The therapy is unusual because it employs a substance naturally occurring in the cancerous cells. This method is part of what Wick called a "rational approach to chemotherapy," in which researchers try to kill cancerous cells without harming normal cells in the body.

Wick said that the first step is to identify a chemical trait unique to the cancerous cells such as the presence of L-dopa. Both melanoma and neuroblastoma are jet-black tumors due to the pigment-producing abilities of their host cells, he said.

L-dopa is the starting material for the synthesis of melanin, a pigment commonly found in skin cells affected by melanoma, a form of skin cancer. In the brain cells affected by neuroblastoma, another form of cancer, L-dopa serves as a starting material for the manufacture of norepinephrine, a chemical signal in the nervous system.

Nerve cells and skin pigment cells are the only cells in the body known to use L-dopa.

Wick decided to "choke the cell" with an overdose of L-dopa--taking what he called "sort of an educated guess," Wick said he believed L-dopa was likely to act only on the nerve and skin pigment cells, and thought it was probably non-toxic to other cells in the body.

Experiments with isolated melanoma cells and with melanoma cells inside mice bore out these predictions.

Scientists do not know how an overdose of L-dopa kills the cancerous cells, but Wick suggested in the Science article that the chemical may inhibit the copying process of DNA, the code of life necessary for new cells to form and grow. Wick believes that an excessive amount of L-dopa may inactivate the key chemical needed for putting together copies of DNA.

Wick added that further studies into the exact mechanism may explain why L-dopa is also successful in controlling Parkinson's Disease.

Wick said last week his research has progressed very quickly.

"It's always luck," he said