1. ¹Molecular Neurosurgery Laboratory, Massachusetts General Hospital, Charlestown, MA, USA
2. ²Harvard Medical School, Boston, MA, USA

Correspondence: Dr SD Rabkin, Molecular Neurosurgery Laboratory, MGH-East, 13th St., Bldg 149, Box 17, Charlestown, MA 02129, USA

³Current address: The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, PR China

Received 7 July 2004; Accepted 2 November 2004; Published online 13 January 2005.

Abstract

Delivery of viral vectors to tumors in the brain is a challenge, especially via systemic administration, which is key to targeting the invasive margins of malignant glioma and the multiple foci of metastatic disease. Like for other cancer therapeutics, the blood–brain barrier or even the blood–tumor barrier significantly limits delivery and efficacy. Blood–brain barrier disruption (BBBD) is one strategy for transiting the cerebrovasculature. G47 is a third-generation oncolytic replication-competent herpes simplex virus (HSV) vector, containing deletions of the 34.5 and 47 genes and an inactivating LacZ insertion in UL39 (ICP6). Intracarotid artery delivery of G47 after BBBD with 25% mannitol significantly extended the life of nude mice bearing intracerebral human MDA-MB-435 breast tumors, whereas, G47 injection contralateral to the tumor, in the absence of mannitol or mannitol alone had no effect on survival. G47 replication was extensive after BBBD, as visualized by X-gal staining. Staining of peripheral organs, lung and liver, was minimal and not altered by BBBD. This is the first demonstration of intracarotid arterial delivery of oncolytic HSV vectors and antitumor efficacy in a mouse model and opens the door to the use of mouse syngenic tumor models and transgenic/knockout animals.