| Ovarian cancer is the leading cause of gynecological disease death in women. For the past two decades, scientists have attempted to perfect the use of adenovirus as an anti-cancer therapeutic agent. One major impediment to ovarian tumor infection with adenovirus has been dearth of adenovirus native receptor, Coxsackie and Adenovirus receptor, (CAR), on the surface of tumor cells. To address this problem, scientists have engineered CAR-independent adenoviruses which target the alphavbeta3 and alpha vbeta5 by adding an arginine-glycine-aspartate (RGD) motif to the fiber knob of a conditionally replicating adenovirus (CRAd) Delta24FiberRGD CRAd. We hypothesize that incorporation of RGD into the pIX motif of the Delta24FiberRGD CRAd, resulting in a Double RGD CRAd, will have increased oncolytic capabilities in in vitro and in vivo ovarian cancer models versus Delta24FiberRGD CRAd.;We produced a Double RGD CRAd (Delta24-pIXRGD-FiberRGD CRAd) by adding a motif to the pIX protein consisting of a 45A linker, a Flag protein (DYKDDDDK) for subsequent verification of incorporation of pIX modification, and the RGD motif to compare its oncolytic ability with that of the previously produced Delta24FiberRGD. This virus was rendered cancer selective by deletion of 24 bases from the E1A region of the adenovirus genome. The presence of RGD motifs at both the pIX and the fiber locales as well as maintenance of the 24-base deletion in the E1 region were verified prior to in vitro and in vivo experimentation. As compared to Delta24 CRAd without RGD modifications, Delta24 CRAd with RGD motif on pIX only, and Delta24 CRAd with RGD motif on Fiber only, Double RGD CRAd showed enhanced oncoloytic ability in vitro and similar oncolytic ability in vivo in an intraperitoneal model of ovarian cancer in nude mice. These data indicate that a viable and oncolytically-enhanced virus may be produced by addition of RGD motifs to both the pIX and fiber motifs of the adenovirus capsid. This strategy provides evidence for the effective use of the pIX protein which may be used in future gene therapy or virotherapy applications that require modification of Ad serotype 5.;Keywords: Adenovirus, Conditionally Replicating Adenovirus (CRAd), ovarian cancer, RGD. |
