On a dark December night in 1948, the American researcher Robert Briggs Watson set out on a perilous 11-hour drive to Shanghai Airport to escape Mao’s communist regime. Despite relentless rain beating down on the windows and mudslides threatening to block the roads, Watson made it aboard the last Pan Am flight out of China.
With him he brought a negligible transport box that would later prove to contain the key to modern-day drug production: 20 Chinese hamsters.
Modifying genes to produce anti-cancer drugs
Carrying his live luggage on board the aircraft, Watson could hardly have foreseen that modern-day biotechnologists would go on to isolate cells from the ovaries of female hamsters, culture the cells, modify their genes—and use them to produce medicinal drugs.
Today, we know that the cells are relatively easy to grow, and that their genes can be modified to produce anti-cancer drugs, haemophiliac medicine, psoriasis medicines, and hormones.
In a laboratory at DTU Biosustain, a so-called bioreactor is hard at work. The machine runs silently. Only a computer screen reveals how the so-called CHO cells—Chinese Hamster Ovary—are performing. A network of interweaving plastic tubes supplies the cells with the right nutrients.
The cells in this experiment are producing the drug Rituximab—a monoclonal antibody that destroys the immune system’s B cells. For healthy people, the substance would be dangerous, but for leukaemia patients whose B cells are hyperactive, not working properly, or are being produced in too large numbers, for example, Rituximab is vital.
“It looks very promising,” says Senior Researcher Helene Faustrup Kildegaard, pointing at the graph on the screen.
The cell is a factory
DTU Biosustain is an international research centre with sections in both Sweden and the USA. In recent years, the centre has worked hard to establish a large unit devoted to CHO cell production. One of the research goals is to force more nutrients to transform from ‘uninteresting’ proteins into anti-cancer drugs within the cell, for example.
“We view the cell as a factory, where our task is to remove all of the machinery not involved in producing the desired drug. We only keep the machinery essential to production,” says Bjørn Voldborg, Director of CHO Cell Line Development.
One of the things that has enabled researchers to make specific changes to the CHO cell metabolism is the mapping of the entire CHO cell genome.