Abstract 1071: Adoptive transfer of T cells overcomes barriers of homing to the tumor microenvironment in ovarian cancer

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Objectives: Chemokine-dependent molecular mechanisms could play a key role in controlling tumor-specific T cell trafficking and the clinical success of adoptive transfer of ex vivo expanded T cells. We thus characterized the chemokine microenvironment in advanced stage serous ovarian cancer and evaluated whether CD3/CD28 co-stimulation of lysate vaccine-primed autologous T cells prepared for adoptive transfer led to the expansion of tumor antigen-reactive T cells able to home to ovarian cancer microenvironment. Methods: The expression of all known human chemokines was analyzed on a gene expression microarray from 63 patients with primary ovarian cancer and was validated on publicly available gene expression dataset and on tissue microarray constructed from a matching cohort of patients. Five HLA-A2 patients with recurrent ovarian cancer, who had previously received vaccination with autologous lysate-pulsed dendritic cell vaccine, underwent apheresis to harvest peripheral blood T cells, which were then expanded using beads coated with anti-CD3/anti-CD28 antibodies and IL-2. T cells were analyzed for 10 chemokine receptors that matched the chemokines expressed in ovarian cancer. Tumor-specific T cells were identified by a HER2/neu pentamer staining. Chemotaxis assays were performed to assess the functionality of these receptors. Results: Chemokines in general were found to be expressed at low level in advanced stage ovarian cancer, with the 10 most highly expressed ones being CCL2, CCL4, CCL5, CCL28, CXCL5, CXCL6 CXCL10, CXCL12, CXCL16 and CX3CL1. The two most commonly expressed chemokine receptors on the expanded cells were CXCR3 and CXCR4 (receptors for CXCL10 and CXCL12). At the end of expansion, 70% of output CD4+ and CD8+ cells expressed CXCR3 and CXCR4, compared to 20% of input T cells. The higher expression of CXCR3 and CXCR4 in output T cells resulted in significantly increased chemotaxis toward CXCL10 and CXCL12, suggesting a better homing ability to the tumor microenvironment. HER2/neu-specific T cells were detected in the expanded T cell population and showed migration toward CXCL10 and CXCL12. Conclusions: Adoptive transfer of ex vivo expanded tumor specific T cells that are capable of tumor engraftment holds a highly promising treatment approach for recurrent ovarian cancer. Chemokines are key regulators of circulation, homing and retention of these cells. Our data confirm that T cells prepared for adoptive transfer through CD3/CD28 bead expansion comprise tumor-specific cells, which upregulate appropriate chemokine receptors and show enhanced migration towards chemokines highly expressed by ovarian cancer. Citation Format: Emese Zsiros, Priyanka Duttagupta, Thomas Garrabrant, Janos L. Tanyi, Lana E. Kandalaft, George Coukos. Adoptive transfer of T cells overcomes barriers of homing to the tumor microenvironment in ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1071. doi:10.1158/1538-7445.AM2014-1071