New Method of Delivery of Gene Therapy May Lead to Safer Treatment for Cancer, Says LIMR

Nanotechnology Offers Improved Therapy for Cancer Patients

Jan 24, 2005, 00:00 ET from Lankenau Institute for Medical Research

    WYNNEWOOD, Pa., Jan. 24 /PRNewswire/ -- The Lankenau Institute for Medical
 Research (LIMR) announced that in collaboration with the Massachusetts
 Institute of Technology (MIT) they have performed preclinical proof-of-
 principle studies showing how nanotechnology can be used to enhance gene
 therapy for cancer.  The results of the study, led by Janet Sawicki, Ph.D. at
 LIMR and Robert Langer, Ph.D. and Daniel Anderson, Ph.D. at MIT, were reported
 as a cover article in a recent issue of the Proceedings of the National
 Academy of Sciences.
     This advance offers an alternative method of gene therapy that has
 advantages over earlier technology.  The nanotechnology-based approach used by
 the researchers has minimal toxic side effects to normal cells.  Moreover, it
 does not rely upon recombinant viruses, the use of which has been questioned
 recently due to the serious adverse effects they can have in some patients.
 Such problems have prompted researchers to find alternative methods for
 delivering gene therapy.
     Dr. Sawicki is an expert in preclinical studies of gene therapy for
 prostate cancer, and she is excited about the success of the current approach.
 In this study, the MIT group identified a polymer termed C32 that the Lankenau
 group demonstrated was capable of delivering genes to cancer cells more
 efficiently and with less toxicity than other polymers that have been tested
 in the field to date.  C32 works by condensing the DNA in a gene and allowing
 the resulting nanoparticles that are formed to enter cells through a process
 called endocytosis.  Therapeutic genes delivered to cells in this manner are
 able to drive cellular production of a gene-encoded protein through normal
     "By genetically engineering the normal diphtheria toxin gene, we created a
 toxin that would be produced only in prostate cells," explained Dr. Sawicki.
 "When we injected prostate tumors in animals with C32 nanoparticles, tumor
 growth was suppressed or reversed, relative to untreated tumors." As part of
 their study, the researchers discovered that C32 nanoparticles deliver DNA
 very efficiently to tumor cells, but very poorly to healthy muscle cells.
 This feature may help safeguard the healthy tissue surrounding tumors,
 offering a significant improvement over currently available therapies, which
 tend to damage the healthy tissue near the tumor.
     In future work, the LIMR and MIT researchers aim to expand their work to
 test whether this nanotechnology can be adapted for a non-radioactive type of
 brachytherapy, a practice that has grown in popularity to treat localized
 prostate cancer, including at Lankenau Hospital. They also aim to explore
 whether nanoparticles can be delivered intravenously to attack metastatic
 tumor cells, which are found throughout the body in advanced stages of cancer.
     Editor's Note:  According to the American Cancer Society, cancer has
 surpassed heart disease as the leading killer of Americans younger than 85.
 In 2005, 232,090 men will be diagnosed with prostate cancer and 30,350 men
 will die from the disease.  Research such as Dr. Sawicki's can lead to
 treatments that will get rid of the cancer completely, leaving healthy cells
 untouched.  In addition, this type of treatment reduces, and possibly
 eliminates, the number of unpleasant side effects associated with prostate
 cancer treatment.

SOURCE Lankenau Institute for Medical Research