Cure rates for patients with multiply relapsed or metastatic solid tumors, particularly sarcomas, remain <30% despite aggressive multimodal therapy including surgery, radiation, and chemotherapy. Our preliminary data suggest highly malignant sarcomas in animal models are susceptible to killing by attenuated herpes simplex virus mutants, such as the ICP6 mutant rRp450. These """"""""oncolytic"""""""" mutant viruses are lytic for many types of cancer cells, but are attenuated in their ability to replicate in normal cells. The mechanisms of cytotoxicity induced by these agents circumvent traditional cancer-resistance mechanisms. Adequate preclinical testing of the efficacy of these agents in an immunocompetent setting has been difficult, particularly for metastatic disease, because of the lack of appropriate tumor models. Here we will exploit a remarkable new mouse model, transgenic for hepatocyte growth factor/scatter factor (HGF/SF-tg) and null for the tumor suppressor locus p16 -INK4A/ARF, to investigate lytic HSV cancer therapy. Nearly 100% of these mice develop spontaneous, highly invasive rhabdomyosarcomas in the first few months of life. Unlike many previous studies of rodent tumor models, our data show cell lines derived from these tumors support robust replication of attenuated HSV mutants. Furthermore, intravenous HSV preferentially targets tumor relative to normal tissues, and improves survival of mice with pulmonary metastases. Intratumoral virus injection results in a marked tumor infiltration of activated T lymphocytes including regulatory T cells. Our overarching hypothesis is that control of local and metastatic sarcoma can be achieved in immunocompetent cancer models using a highly lytic but attenuated HSV mutant, and that the antitumor activity is driven by both viral and immune-mediated cytolytic effects. Furthermore, elucidation of the mechanisms of virus targeting to metastatic sites and regulation of the immune response will permit rational design of strategies to improve cancer control with these agents. Our long-term goal is to better understand the therapeutic effects of oncolytic HSV mutants for cancer. We will test our hypotheses using an HSV-susceptible, immunocompetent mouse sarcoma model that emulates human disease more closely than previously possible.
Our aims are:
Aim 1 : Determine the mechanism of systemic HSV tumor targeting in the setting of multiple sites of metastases.
Aim 2 : Test the effect of antiangiogenic agents on the systemic delivery and antitumor efficacy of oncolytic HSV.
Aim 3 : Define the role of cytotoxic and regulatory T cells in tumor shrinkage following intratumoral HSV therapy. These studies will elucidate mechanisms of tumor-selective virus delivery and immunologic-mediated cytotoxicity and test specific strategies to improve the antitumor effect of oncolytic HSV for metastatic disease. Our results will guide the design of future clinical trials using these novel agents.
|Haworth, Kellie B; Leddon, Jennifer L; Chen, Chun-Yu et al. (2015) Going back to class I: MHC and immunotherapies for childhood cancer. Pediatr Blood Cancer 62:571-6|
|Cripe, Timothy P; Ngo, Minhtran C; Geller, James I et al. (2015) Phase 1 study of intratumoral Pexa-Vec (JX-594), an oncolytic and immunotherapeutic vaccinia virus, in pediatric cancer patients. Mol Ther 23:602-8|
|Wang, P-Y; Currier, M A; Hansford, L et al. (2013) Expression of HSV-1 receptors in EBV-associated lymphoproliferative disease determines susceptibility to oncolytic HSV. Gene Ther 20:761-9|
|Currier, Mark A; Eshun, Francis K; Sholl, Allyson et al. (2013) VEGF blockade enables oncolytic cancer virotherapy in part by modulating intratumoral myeloid cells. Mol Ther 21:1014-23|
|Kaur, Balveen; Chiocca, E Antonio; Cripe, Timothy P (2012) Oncolytic HSV-1 virotherapy: clinical experience and opportunities for progress. Curr Pharm Biotechnol 13:1842-51|
|Eshun, F K; Currier, M A; Gillespie, R A et al. (2010) VEGF blockade decreases the tumor uptake of systemic oncolytic herpes virus but enhances therapeutic efficacy when given after virotherapy. Gene Ther 17:922-9|
|Maldonado, Arturo R; Klanke, Chuck; Jegga, Anil G et al. (2010) Molecular engineering and validation of an oncolytic herpes simplex virus type 1 transcriptionally targeted to midkine-positive tumors. J Gene Med 12:613-23|
|Hammill, Adrienne M; Conner, Joseph; Cripe, Timothy P (2010) Oncolytic virotherapy reaches adolescence. Pediatr Blood Cancer 55:1253-63|
|Kaur, Balveen; Cripe, Timothy P; Chiocca, E Antonio (2009) ""Buy one get one free"": armed viruses for the treatment of cancer cells and their microenvironment. Curr Gene Ther 9:341-55|
|Geller, James I; Cripe, Timothy P (2009) Adenovirus gene therapy for pediatric cancers: shall we gather at the liver? Pediatr Blood Cancer 53:133-5|
Showing the most recent 10 out of 18 publications