Active efflux of Dasatinib from the brain limits efficacy against murine glioblastoma: broad implications for the clinical use of molecularly targeted agents.

The importance of the blood-brain barrier in preventing effective pharmacotherapy of glioblastoma has been controversial. The controversy stems from the fact that vascular endothelial cell tight junctions are disrupted in the tumor, allowing some systemic drug delivery. P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) efflux drugs from brain capillary endothelial cells into the blood.

An in vivo immunotherapy screen of costimulatory molecules identifies Fc-OX40L as a potent reagent for the treatment of established murine gliomas.

Purpose: We tested the combination of a tumor lysate vaccine with a panel of costimulatory molecules to identify an immunotherapeutic approach capable of curing established murine gliomas.

Experimental Design: Glioma-bearing mice were primed with a tumor lysate vaccine, followed by systemic administration of the following costimulatory ligands: OX40L, CD80, 4-1BBL, and GITRL, which were fused to the Fc portion of human immunoglobulin. Lymphocytes and mRNA were purified from the brain tumor site for immune monitoring studies.

COX-2 blockade suppresses gliomagenesis by inhibiting myeloid-derived suppressor cells.

Epidemiologic studies have highlighted associations between the regular use of nonsteroidal anti-inflammatory drugs (NSAID) and reduced glioma risks in humans. Most NSAIDs function as COX-2 inhibitors that prevent production of prostaglandin E₂ (PGE₂). Because PGE₂ induces expansion of myeloid-derived suppressor cells (MDSC), we hypothesized that COX-2 blockade would suppress gliomagenesis by inhibiting MDSC development and accumulation in the tumor microenvironment (TME).

Role of type 1 IFNs in antiglioma immunosurveillance--using mouse studies to guide examination of novel prognostic markers in humans.

Purpose: We hypothesized that the type 1 IFNs would play a pivotal role in antiglioma immunosurveillance through promotion of type 1 adaptive immunity and suppression of immunoregulatory cells.

Experimental Design: We induced de novo gliomas in Ifnar1(-/-) (deficient for type 1 IFN receptors) or wild-type mice by intracerebroventricuar transfection of NRas and a short hairpin RNA against P53 using the Sleeping Beauty transposon system. We analyzed the survival of 587 glioma patients for single nucleotide polymorphisms (SNP) in type 1 IFN-related genes.

De novo induction of genetically engineered brain tumors in mice using plasmid DNA.

Spontaneous mouse models of cancer show promise to more accurately recapitulate human disease and predict clinical efficacy. Transgenic mice or viral vectors have been required to generate spontaneous models of glioma, a lethal brain tumor, because nonviral gene transfer is typically transient. To overcome this constraint, we used the Sleeping Beauty transposable element to achieve chromosomal integration of human oncogenes into endogenous brain cells of immunocompetent mice.