Scatter factor/hepatocyte growth factor is a pleiotropic growth factor that binds to c-Met, a proto-oncogene encoded tyrosine kinase receptor ubiquitously present on most malignant gliomas. This grant application seeks to infuse thawed allogeneic T cells that have been rendered c-Met-specific for the treatment of gliomas.
Buidling upon on our experience infusing autologous and allogeneic T cells genetically modified to express a chimeric antigen receptor (CAR) to redirect specificity for a desired cell-surface antigen (such as CD19 on B-cell malignancies) and our novel platform technologies that have been adapted for clinical translation using (i) the Sleeping Beauty (SB) transposon/transposase system to stably express CAR transgenes and (ii) artificial antigen presenting cells (aAPC) derived from K562 cells to propagate genetically modified T cells in a CAR-dependent manner to clinically-sufficient numbers.
We have designed a 2nd generation CAR, designated cMetRCD28, to render T cells specific for c-Met independent of MHC. To conditionally activate cMetRCD28+ T cells under conditions of hypoxia thereby limiting deleterious targeting of normal tissues expressing c-Met, this CAR has been fused to the oxygen-dependent degradation domain (ODDD) which results in degradation of cell-surface CAR-ODDD protein under conditions of normoxia, but not hypoxia found in the tumor microenvironment.
To generate allogeneic T cells from a 3rd party to be infused “on demand” we will co-express the CAR-ODDD with designer zinc finger nuclease (ZFN) (or inhibiting RNA species) to eliminate endogenous expression of alpha/beta T-cell receptor (TCR). The cMetRCD28-ODDD and ZFN transgenes will be electro-transferred into T cells using the SB system and selectively propagated on c-Met+ aAPC.
This approach will be further developed to co-express a mutein of thymidine kinase (sr39TK) from herpes simplex virus-1 for in vivo conditional ablation with ganciclovir and imaging by positron emission tomography (PET). Aim #1 evaluates whether cMetRCD28+TK+TCRneg T cells lyse gliomas. The ability for these T cells to survive/propagate under hypoxia will be determined.
Aim #2 evaluates the ability of cMetRCD28+TK+TCRneg T cells to selectively eliminate hypoxic c-Met+ glioma in an orthotopic xenogeneic mouse tumor model, using bioluminescent imaging and micro-PET to asses T-cell persistence and anti-tumor effect. Aim #3 evaluates in a human Phase I clinical trial the safety, feasibility, persistence and efficacy of thawed allogeneic cMetRCD28+TK+TCRneg T cells delivered loco-regionally after initial resection. PET/CT imaging using [18F]-FHBG metabolized by sr39TK will be used to evaluate the distribution of adoptively transferred T cells.
In aggregate, these studies will develop new targeted cell and gene therapy for gliomas using our established clinical platform technologies and as c-Met is expressed on many extra-cranial solid tumors this approach may have broad application.