Formation of in vitro immunological synapses (IS) between anti-glioma CTLs and glioma cells: functional and molecular consequences, and examination of the role of small GTPases.

PUNTEL; BARRET; YANG; SANDERSON; CURTIN; BONDALE; ASSI; KROEGER; CASTRO; LOWENSTEIN

San Diego, California, USA

Congreso; American Association for Cancer Research; 2008

Abstract #1017Formation of in vitro immunological synapses (IS) between anti-glioma CTLs and glioma cells: functional and molecular consequences, and examination of the role of small GTPases.Mariana Puntel, Robert Barrett, Jieping Yang, Nicholas Sanderson, James Curtin, Niyati Bondale, Hikmat Assi, Kurt Kroeger, Maria Castro and Pedro LowensteinBoard of Governors Gene Therapeutics Research Institute, Cedars-Sinai Medical Center and Department of Medicine and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CAImmunological synapses (IS) mediate intercellular communication between T cells and APCs. T cell polarization at the Kupfer-type IS consists of a peripheral supramolecular activation cluster (pSMAC), which is high in LFA-1, and a central SMAC, high in TCR. Target virally infected astrocytes also polarize towards the immunological synapse with anti-viral CTLs in vivo. Astrocyte polarization in response to physical lesions in vitro is mediated through the activation of a signaling pathway mediated by a family of Rho-GTPases, and coordinated by Cdc42. Glioma cells in culture also polarize their cytoskeleton and intracellular organelles in response to a physical lesion. Intratumoral treatment of animals bearing syngeneic intracranial gliomas with adenoviruses (Ad) expressing HSV1-TK and Flt3L leads to the proliferation of tumor specific CTLs and the eventual eradication of the tumor is ~50% of the mice. Here we tested the hypothesis that that stimulation of a Rho-GTPase cascade underlies in vitro GL26 glioma cell polarization in response to an immune attack. To do so, we treated tumor-bearing mice with Ad-TK and Ad-Flt3L and isolated CTLs 7 days later. CTLs were co-cultured with GL26 glioma cells in vitro infected with adenoviral vectors expressing a dominant negative variants of Cdc42 (Cdc42DN), Rac (DNRac), or Rho (DNRho) and analyzed their responses to a T cell attack. Ad vectors expressing wildtype Cdc42, Rac, and Rho were used as controls. Understanding the physiology of immunological synapses between T cells and tumor cells, and their consequences to the survival or demise of tumor glioma cells will improve the efficiency of targeted immune therapies of glioma.