Adenovirus-mediated targeted expression of toxic genes to adrenocorticotropin-producing pituitary tumors using the proopiomelanocortin promoter.
Management of Cushing's disease remains challenging, despite advances in its diagnosis and treatment. Here, we describe a strategy for targeting the expression of toxic genes to ACTH-producing tumor cells using adenoviral vectors. The POMC promoter was used to express either a marker gene (beta-galactosidase) or a toxic gene [herpes simplex virus thymidine kinase (TK)]. In ACTH-producing AtT20 cells, infection with recombinant adenoviruses containing the POMC promoter (AdPOMCGal; AdPOMCTK) led to high-level gene expression. Stereotactic injection of AdPOMCGal into the rat pituitary resulted in localized expression of the beta-galactosidase transgene in corticotrope cells. Cytotoxicity studies were performed using the TK-containing vectors and treatment with ganciclovir. AdPOMCTK caused greater than 95% cytotoxicity of AtT20 cells at a viral dose (multiplicity of infection, 5 plaque-forming units/cell) that induced minimal toxicity using control viruses. No cellular toxicity was seen using a nonpituitary cell line (T47D breast tumor cells). AtT20 cells transplanted into nude mice induced features of Cushing's syndrome and were used as an in vivo model of ACTH-producing tumors. Injection of the AdPOMCTK virus caused significant regression of the transplanted AtT20 tumors. These studies suggest that the POMC promoter may provide a useful gene therapy strategy for the adjunctive treatment of pituitary tumors causing ACTH-dependent Cushing's syndrome.
Lee
E J
EJ
Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Martinson
F
F
Kotlar
T
T
Thimmapaya
B
B
Jameson
J L
JL
D000256:Adenoviridae / Q000235:genetics*; D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis*; D000818:Animals; D002460:Cell Line; D004274:DNA, Recombinant / Q000008:administration & dosage; D015774:Ganciclovir / Q000008:administration & dosage; D015870:Gene Expression; D018390:Gene Targeting; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D011333:Pro-Opiomelanocortin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D018139:Simplexvirus / Q000201:enzymology; D013937:Thymidine Kinase / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D001616:beta-Galactosidase / Q000235:genetics
D004274:DNA, Recombinant; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D013937:Thymidine Kinase; D001616:beta-Galactosidase; D015774:Ganciclovir