Interim progress report

Sensitivity of Head and Neck Cancer to Herpes Oncolytic Therapy

2004 AHNS - ACS Career Development Award

Richard J. Wong, MD Principal Investigator

Award period: 2004-2006. Published July 11, 2005

Progress: We thank the AHNS for their kind and generous support of this research. We are pleased with our progress over the past year related to this project. We have performed the majority of the experiments proposed and have had very encouraging results. In brief, we have determined the sensitivity of a variety of head and neck cancer cell lines to an oncolytic herpes virus (NV1023) through a variety of in vitro assays. We then performed an analysis of the HSV receptor profile on these cell lines by quantitative FACS and cellular Elisa. We drew significant correlations using Pearson’s coefficients between using two measures of HSV receptors (nectin-1 and total glycoprotein D receptor expression) and successful NV1023 viral entry and cytotoxicity. We validated these findings mechanistically by blocking the nectin-1 receptor to show inhibition of NV1023 entry. We then developed an immunohistochemical method of assessing nectin-1 expression on fresh tumor tissue from an animal model, and correlated response to NV1023 in vivo to intensity of nectin-1 staining. These findings strongly suggest that we can use our assays of nectin-1 and total gD receptor expression to predict response to oncolytic HSV. We expect that these findings are a first step towards developing a prediction model of response to oncolytic HSV which can be applied to our future, planned clinical trials with these vectors in head and neck cancers. Our early results were recently presented by our group at the annual AACR meeting at Anaheim, CA, in April 2005.

Abstracts and Manuscripts:

Yu Z, Chan MK, O-charoenrat P, Eisenberg DP, Shah JP, Singh B, Fong Y, Wong RJ. Enhanced Nectin-1 Expression and Herpes Oncolytic Sensitivity in Highly Migratory and Invasive Carcinoma. Clin Cancer Res. 2005 July 1; 11(13), in press.

Yu Z, Adusumilli PS, Eisenberg DP, Li S, Liu S, Singh B, Shah JP, Fong Y, Wong RJ. Expression of Nectin-1 by Squamous Cell Carcinoma Predicts Sensitivity to Herpes Oncolytic Therapy. April 18, 2005. American Association for Cancer Research Annual Meeting. Anaheim, CA.

Expenditures for the First Year: Our receipt of grant funding was significantly delayed due to an administrative error at the ACS, and funds did not arrive until February 2005. This issue was eventually worked out with the kind assistance of Ms. Kate Early and Mr. Efren Ortiz from the American College of Surgeons. In January 2005, they kindly sent us a letter of regret and a no-cost extension of the grant. Therefore, we have only recently had an opportunity to begin using these funds for the purchase of antibodies. We are planning to purchase animals, pay animal housing costs, additional antibodies, experimental reagents, and pay many other expenses in the coming months.

Budget and Plans for the Second Year: We have made interesting observations in the past year that we will plan to further investigate in the second year. We are currently investigating the role of other HSV receptors (such as heparin sulfate which is bound by HSV gB and gC) on head and neck cancer cells as additional determinants of NV1023 therapy. We are also exploring other non-receptor, cellular determinants of permissiveness to HSV replication and oncolysis as well, and will seek to integrate these findings into our prediction model.

We have developed a productive relationship with Dr. Patricia Spear, a leading HSV virologist at Northwestern University. Using her previous studies as our foundation, we have recently determined that the nectin-1 levels on head and neck cancer cells can be significantly enhanced by disruption intercellular adherens junctions, which liberates nectin-1 from these junctions to serve as HSV receptors. This can be achieved by depletion of extracellular calcium through chelation with EDTA or other agents. Our preliminary work has determined that calcium depletion for head and neck cancer cells can significantly enhance NV1023 viral entry and cytotoxicity in vitro. We will seek to validate these preliminary findings, and apply this strategy to an in vivo model of injected EDTA. We will also seek to understand the relationship between E-cadherin loss, a frequently observed finding in head and neck cancers which disrupts adherens junctions, and the amount of nectin-1 expression detected these cell lines. We hypothesize that a loss of E-cadherin may enhance susceptibility to oncolytic HSV therapy though a nectin-1 mechanism. We will explore these and other concepts in our second year of funding.