Directed evolution generates a novel oncolytic virus for the treatment of colon cancer.
BACKGROUND
Viral-mediated oncolysis is a novel cancer therapeutic approach with the potential to be more effective and less toxic than current therapies due to the agents selective growth and amplification in tumor cells. To date, these agents have been highly safe in patients but have generally fallen short of their expected therapeutic value as monotherapies. Consequently, new approaches to generating highly potent oncolytic viruses are needed. To address this need, we developed a new method that we term "Directed Evolution" for creating highly potent oncolytic viruses.


RESULTS
Taking the "Directed Evolution" approach, viral diversity was increased by pooling an array of serotypes, then passaging the pools under conditions that invite recombination between serotypes. These highly diverse viral pools were then placed under stringent directed selection to generate and identify highly potent agents. ColoAd1, a complex Ad3/Ad11p chimeric virus, was the initial oncolytic virus derived by this novel methodology. ColoAd1, the first described non-Ad5-based oncolytic Ad, is 2-3 logs more potent and selective than the parent serotypes or the most clinically advanced oncolytic Ad, ONYX-015, in vitro. ColoAd1's efficacy was further tested in vivo in a colon cancer liver metastasis xenograft model following intravenous injection and its ex vivo selectivity was demonstrated on surgically-derived human colorectal tumor tissues. Lastly, we demonstrated the ability to arm ColoAd1 with an exogenous gene establishing the potential to impact the treatment of cancer on multiple levels from a single agent.


CONCLUSIONS
Using the "Directed Evolution" methodology, we have generated ColoAd1, a novel chimeric oncolytic virus. In vitro, this virus demonstrated a >2 log increase in both potency and selectivity when compared to ONYX-015 on colon cancer cells. These results were further supported by in vivo and ex vivo studies. Furthermore, these results have validated this methodology as a new general approach for deriving clinically-relevant, highly potent anti-cancer virotherapies.
Novel Technologies, Bayer Healthcare, Richmond, California, United States of America.
Irene
I
Kuhn
Paul
P
Harden
Maxine
M
Bauzon
Cecile
C
Chartier
Julie
J
Nye
Steve
S
Thorne
Tony
T
Reid
Shaoheng
S
Ni
Andre
A
Lieber
Kerry
K
Fisher
Len
L
Seymour
Gabor M
GM
Rubanyi
Richard N
RN
Harkins
Terry W
TW
Hermiston
D000256:Adenoviridae / Q000502:physiology; D000818:Animals; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000628:therapy*; D019020:Directed Molecular Evolution; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary; D051379:Mice; D009368:Neoplasm Transplantation; D050130:Oncolytic Virotherapy; D050504:Oncolytic Viruses / Q000235:genetics / Q000502:physiology*