Intravenous RNA interference gene therapy targeting the human epidermal growth factor receptor prolongs survival in intracranial brain cancer.
OBJECTIVE
The human epidermal growth factor receptor (EGFR) plays an oncogenic role in solid cancer, including brain cancer. The present study was designed to prolong survival in mice with intracranial human brain cancer with the weekly i.v. injection of nonviral gene therapy causing RNA interference (RNAi) of EGFR gene expression.


METHODS
Human U87 gliomas were implanted in the brain of adult scid mice, and weekly i.v. gene therapy was started at day 5 after implantation of 500000 cells. An expression plasmid encoding a short hairpin RNA directed at nucleotides 2529-2557 within the human EGFR mRNA was encapsulated in pegylated immunoliposomes. The pegylated immunoliposome was targeted to brain cancer with 2 receptor-specific monoclonal antibodies (MAb), the murine 83-14 MAb to the human insulin receptor and the rat 8D3 MAb to the mouse transferrin receptor.


RESULTS
In cultured glioma cells, the delivery of the RNAi expression plasmid resulted in a 95% suppression of EGFR function, based on measurement of thymidine incorporation or intracellular calcium signaling. Weekly i.v. RNAi gene therapy caused reduced tumor expression of immunoreactive EGFR and an 88% increase in survival time of mice with advanced intracranial brain cancer.


CONCLUSIONS
Weekly i.v. nonviral RNAi gene therapy directed against the human EGFR is a new therapeutic approach to silencing oncogenic genes in solid cancers. This is enabled with a nonviral gene transfer technology that delivers liposome-encapsulated plasmid DNA across cellular barriers with receptor-specific targeting ligands.
Zhang
Yun
Y
Departments of Medicine and Neurology, University of California Los Angeles, Los Angeles, California 90024, USA.
Zhang
Yu-Feng
YF
Bryant
Joshua
J
Charles
Andrew
A
Boado
Ruben J
RJ
Pardridge
William M
WM
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000098:blood supply / Q000378:metabolism; D001932:Brain Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000628:therapy*; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004705:Endocytosis; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D008024:Ligands; D008081:Liposomes / Q000737:chemistry; D051379:Mice; D018613:Microscopy, Confocal; D008954:Models, Biological; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D009841:Oligonucleotides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D034622:RNA Interference; D015398:Signal Transduction; D013936:Thymidine / Q000737:chemistry / Q000378:metabolism; D013997:Time Factors; D016896:Treatment Outcome
D008024:Ligands; D008081:Liposomes; D009841:Oligonucleotides; D011092:Polyethylene Glycols; D004247:DNA; D066246:ErbB Receptors; D002118:Calcium; D013936:Thymidine