A novel chromogranin-A promoter-driven oncolytic adenovirus for midgut carcinoid therapy.
OBJECTIVE
The use of replication-selective oncolytic adenoviruses is an emerging therapeutic approach for cancer, which thus far has not been employed for carcinoids. We therefore constructed Ad[CgA-E1A], a novel replication-selective oncolytic adenovirus, where the chromogranin A (CgA) promoter controls expression of the adenoviral E1A gene.


METHODS
The Ad[CgA-E1A] virus was evaluated for E1A protein expression, replication ability, and cytolytic activity in various cell lines. It was also evaluated for treatment of xenografted human carcinoid tumors in nude mice. To use Ad[CgA-E1A] for the treatment of carcinoid liver metastases, it is important that normal hepatocytes do not support virus replication to minimize hepatotoxicity. We therefore evaluated CgA protein expression in normal hepatocytes. We also evaluated CgA gene expression in normal hepatocytes and microdissected tumor cells from carcinoid metastases.


RESULTS
We found that Ad[CgA-E1A] replicates similarly to wild-type virus in tumor cells with neuroendocrine features, including the BON carcinoid cell line and the SH-SY-5Y neuroblastoma cell lines, whereas it is attenuated in other cell types. Thus, cells where the CgA promoter is active are selectively killed. We also found that Ad[CgA-E1A] is able to suppress fast-growing human BON carcinoid tumors in nude mice. Furthermore, CgA is highly expressed in microdissected cells from carcinoid metastases, whereas it is not expressed in normal hepatocytes.


CONCLUSIONS
Ad[CgA-E1A] is an interesting agent for the treatment of carcinoid liver metastases in conjunction with standard therapy for these malignancies.
Leja
Justyna
J
Division of Clinical Immunology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
Dzojic
Helena
H
Gustafson
Elisabet
E
Oberg
Kjell
K
Giandomenico
Valeria
V
Essand
Magnus
M
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D002276:Carcinoid Tumor / Q000473:pathology / Q000628:therapy*; D002460:Cell Line; D045744:Cell Line, Tumor; D053379:Chromogranin A / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics; D005784:Gene Amplification; D006801:Humans; D007668:Kidney; D008113:Liver Neoplasms / Q000556:secondary / Q000628:therapy; D051379:Mice; D008819:Mice, Nude; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000628:therapy*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011995:Recombination, Genetic; D014183:Transplantation, Heterologous
D053379:Chromogranin A; D004279:DNA, Viral