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Biologist offers new hope for Valley sugar as pharmaceutical
LYNN BREZOSKY
Associated Press - Mar. 11, 2005 - SANTA ROSA, Texas - On a March day trucks full of burnt cane stalks dot the lonely road to the sugar mill and the smell of molasses moves with the wind. Bulldozers scoop bits of this year's processed harvest - a 70,000-ton mountain of raw sugar - onto barges bound for Louisiana refineries.
Half the pile will sit in warehouses, underpriced by foreign competitors and stalled by federal quotas. It's a bleak scene for farmers, but a Texas A&M molecular biologist offers hope.
Erik Mirkov has genetically engineered sugar cane with a human gene to produce a human therapeutic protein. Such a protein could replace the need to farm cadavers for face-plumping collagen and provide a more affordable alternative to fermenting hamster cells for cancer treatments.
It also could turn some varieties of Texas sugar into a more profitable crop. Some proteins used by pharmaceutical companies now are selling for more than $1 million a gram.
But the research worries environmentalists, who fear the proteins from such "pharma plants" may somehow get loose and contaminate conventionally grown food crops.
A number of scientists are raising crops spliced with human genes, which coax the plants to produce proteins that then are extracted and turned into drugs known as biologics, which Mirkov said would be easier to produce and less expensive than conventional pharmaceuticals.
One cancer drug being tested now at Stanford University is derived from the tobacco plant, while other suitable crops include corn and rice.
But Mirkov said sugar cane's simple genetic makeup compared to other crops would make the splicing with human genes easier and less expensive.
By comparison, he cited his wife Kaye's successful treatment of non-Hodgkins lymphoma with a protein-based drug called Rituxan, which at the time cost $8,000 for one treatment. His wife needed eight.
Rituxan, manufactured by Genentech Inc., latches on to cancer cells so that the body will destroy them. The same principles are behind hundreds of drugs being used against other ailments including breast cancer, rheumatoid arthritis, and Crohn's disease.
By the time his wife's cancer was being treated with Rituxan, Mirkov was already well under way with his research and was confident plants could be used to make the treatments more plentiful and less expensive. And while the proteins need an expensive purification process, Mirkov said sugar cane's simple makeup compared to other crops would ease the process.
Most protein-based drugs are made from animal cells, which are reproduced by fermentation in 10,000-liter vats that are costly to build. The vats available are working near capacity, Mirkov said. The only capital cost involved with creating sugar-derived drugs is the cost of planting the field.
"People have turned to plants as a biofactory," he said, although it could be years before the proteins are ready for use.
He said similar research on sugar cane is being done in Hawaii.
But the global environmental concerns persist.
Prodigene Inc., of College Station, Texas, successfully made protein from corn they grew in Nebraska. But when the field was cleared to prepare to grow soybeans, some of the engineered corn poked through, causing a bioengineering scare.
Some 3 million bushels of soybeans already harvested had to be incinerated. Ingesting a genetically altered crop can be fatal, Mirkov said.
Neil Carman, with the Sierra Club's national genetic engineering committee, warned that entire European and other markets - as well as some U.S. manufacturers - might reject Texas sugar.
"Somebody buying it may say 'we don't want any collagen in the sugar cane we're buying ... we don't want any sugar cane if it's growing in an area where there's some kind of genetically engineered crop, he said.
"There's just a lot of unanswered questions here. The science is still brand new and we need a lot more testing and research and studies before this stuff should really be put out into the field."
But sugar cane propagates without seed and because U.S.-grown sugar stalks are "tough as a two-by-four" in Mirkov's words, it's unlikely to be chewed as is common in other countries.
For now, the super sugarcane grows in greenhouses at Texas A&M.
Some transgenic sugarcane resistant to insects, viruses and herbicides is growing in experimental fields around the Rio Grande Valley. While Mirkov is trying to increase the amount of protein each plant produces, right now it would take 9,000 acres of sugar cane to make a ton of protein for use by drug companies - for some existing cancer treatments enough to treat 150,000 people.
Having a market for that much sugar cane would be welcome news for sugar growers.
Sugar was brought to the Rio Grande Valley in the late 19th century and rooted quickly. At Texas sugar's height, the Valley had five mills. But before long, sugar was being produced more cheaply in the Caribbean and other places, and by 1921, the last of the mills shut down.
In the early 1970s, as America's sugar consumption soared, it became the Valley's comeback crop. Although some say the crop is too thirsty for the region, it returns more than cotton, and is less fragile than citrus.
Growers formed a cooperative to build and operate the only cane mill now operating in Texas.
"Mass produced candies, cakes, sodas - then, there wasn't enough," said Humberto Vela, the mill director of the mill.
The mill has produced 1.5 million tons of raw sugar since the 1970s - a fraction of what is produced in Florida, Louisiana or Hawaii.
Farmers get their orders at the start of five-year cycles, which is how they ended up producing more than the government allowed.
Five years ago, the region was in severe drought and farmers couldn't make tonnage. Last year the cooperative was unable to sell 36,000 tons.
The answer now seems to be selling the land or switching the crop, but the sugar growers are keeping tabs on Mirkov's research.
Growers just want to sell their sugarcane, Vela said, whether for medicines or breakfast cereals. So If science is the new market for sugar cane, Vela said, that's fine with them.
"On a level playing field our farmers can compete with anybody in the world," he said. "But I'm going to assume that till the research shows there's something really good they'll be reluctant to jump in - because they lost so many times."
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