Human Health Issues

The same chemistry that led to the successful cloning of a mule at the University of Idaho this month also may shed new light on the causes of diabetes, specific cancers and other age-onset diseases in humans.

According to UI Professor of Animal and Veterinary Science Gordon Woods, leader of the UI-Utah State University team that in May 2003 produced the first mule clone, the chemical changes necessary for the successful cloning provide new insight about what influences cell growth and activity. In addition, Woods, who also serves as director of the UI's Northwest Equine Reproduction Laboratory, said the horse provides a novel and effective model for studying cancer metastasis and other age-onset diseases in humans.

"The mortality rate for horses with metastatic cancer is 8 percent for all cancers and 0 percent for prostate cancer. By comparison, the mortality rate in humans is approximately 24 percent for all cancers, of which 13 to 14 percent are for prostate cancer," Woods said. "The contrasts and similarities between humans and horses at the cellular level provide a number of insights about how the relationship of certain chemicals in the body affect both normal and abnormal cell activity."

Calcium - more importantly, the relationship between the amount of calcium within each cell and outside each cell - is key. Members of the horse family have a lower amount of intracellular calcium than humans and a correspondingly slower rate of cell activity.

Woods said when his team first started its cloning work in 1998, only a very few of the implants resulted in pregnancies, and none of those progressed past the four-week point. Based on new information provided by CancEr2, a private corporation founded by Woods, the scientists agreed part of the problem was the relatively slow rate of cell activity in members of the horse family. Woods noted that the slow rate of cell activity may be why in vitro fertilization doesn't work in horses and may be why the cancer mortality rate among horses is so low.

In July 2001, however, the team supplemented the amount of calcium in the implanted clones. "We increased the calcium in the medium holding the embryos and saw a seven-fold increase in our week two pregnancy rates," Woods said. "We produced 19 pregnancies; the first baby has been born, and two more pregnancies are in the advanced stages."

The team concluded that the increase in calcium within the implanted clone cells directly impacted the speed of cell division. Understanding the role of calcium in equine cell activity was a direct result of work conducted by Cancer2. Cancer2 gifted the intellectual property to UI.

According to existing research, the amount of intracellular calcium is higher than normal in humans with metastasizing cancer. According to Woods' research, the amount of intracellular calcium is below normal in horses. Within Cancer2, Woods and his team have discovered a chemical that suppresses intracellular calcium. Abnormally high intracellular calcium is a root cause of abnormally high cell activity in aged humans.

"There are electrifying similarities between cancer metastasis and embryo division," said Woods. He said he is working toward critical testing of the effects of deficiencies in the suppressor in human clinical trials. "We've identified a suppressor of intracellular calcium and believe its deficiency is the root cause of abnormally high intracellular calcium."