Express delivery for cancer drugs.A new drag-delivery method has dramatically reduced tumors in experiments conducted with mice. Bert Vogelstein Bert Vogelstein (born 1949) is a noted cancer researcher at The Johns Hopkins University. His first degree was in mathematics graduating summa cum laude in 1970 from the University of Pennsylvania. His interest was more in medicine and he received his M.D. and his colleagues at the Johns Hopkins cancer center in Baltimore injected mice with microscopic containers, called liposomes Liposomes Aqueous compartments enclosed by lipid bilayer membranes; liposomes are also known as lipid vesicles. Phospholipid molecules consist of an elongated nonpolar (hydrophobic) structure with a polar (hydrophilic) structure at one end. , loaded with the anti-cancer drag doxorubicin doxorubicin /doxo·ru·bi·cin/ (dok?so-roo´bi-sin) an antineoplastic antibiotic, produced by Streptomyces peucetius, which binds to DNA and inhibits nucleic acid synthesis; used as the hydrochloride salt and as a liposome-encased . The blood vessels Blood vessels Tubular channels for blood transport, of which there are three principal types: arteries, capillaries, and veins. Only the larger arteries and veins in the body bear distinct names. in and around tumors tend to have larger-than-normal pores, so the liposomes pass into and accumulate in cancerous tissues more readily than they do in healthy ones. The liposomes eventually rapture, releasing the drug. At the same time, the scientists injected the mice with spores of the modified bacterium Clostridiurn novyi-NT, which comes to life only in environments depleted de·plete tr.v. de·plet·ed, de·plet·ing, de·pletes To decrease the fullness of; use up or empty out. [Latin d of oxygen. Because tumors grow faster than their blood supply, their centers usually lack oxygen. Researchers had noted that the bacterium releases a protein that breaks down the membranes of red blood cells Red blood cells Cells that carry hemoglobin (the molecule that transports oxygen) and help remove wastes from tissues throughout the body. Mentioned in: Bone Marrow Transplantation red blood cells . The Johns Hopkins team decided to combine the therapies, predicting that the protein would penetrate the liposomes and make them deliver their load of drug more efficiently. The strategy succeeded: Human-colon tumors vanished in mice receiving the combination treatment, but the cancer continued growing in animals getting either treatment alone, the researchers report in the Nov. 24 Science. "It's worked remarkably well compared to other therapies, melting away very large tumors," says Kenneth W. Kinzler, an author of the new report. He and his coauthors caution that the method has a long way to go before it can be used in people.--J.J.R |
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