A T-Sign Cancer Gene Therapy Virus Expressing An Epcam-Targeted Bispecific T-Cell Activator Stimulates T-Cells And Induces Tumor Cell Death In Patient-Derived Organotypic Non-Small Cell Lung Cancer (Nsclc) Spheroids Ex Vivo.

Abstract Tumor-Specific Immuno-Gene (T-SIGn) cancer gene therapy vectors, which are based on the oncolytic adenovirus enadenotucirev, carry a gene cassette encoding combinations of human transgenes under control of the virus major late promoter (MLP) which restricts expression to tumor cells. These vectors can be dosed intravenously for delivery to tumors and selective expression of therapeutic proteins locally within the tumor microenvironment. Because these viruses only infect human tumor cells, in vivo studies are limited to human tumor xenografts in immunodeficient mice. Recently, we have optimized a 3D microfluidic system for evaluating response to immunotherapies using patient-derived organotypic tumor spheroids (PDOTS). PDOTS contain stromal as well as autologous myeloid and lymphoid cell populations and respond to PD-1 blockade in short-term ex vivo culture. As an alternative preclinical approach for evaluating activity and mechanistic underpinnings of T-SIGn viruses expressing human immunomodulatory transgenes, we have been developing the PDOTS ex vivo culture model. Here we report on the visualization of oncolytic virus uptake, replication in tumor cells and activation of T cells with a T-SIGn virus encoding an EpCAM-targeted bispecific T-cell activator (NG-611) within NSCLC PDOTS. Surgical NSCLC cases from St. Elizabeth's Medical Center, collected under an IRB approved protocol, were processed in PDOTS and assessed for EpCAM expression and number of T cells. Five different samples were treated with NG-611 (mixed with a GFP expressing vector) at concentrations ranging from 2x109 to 2x106 vp/mL final volume of culture. Virus infection was shown after 3 and 5 days of culture by dose-dependent expression of GFP reporter transgene driven by a CMV promoter, and virus replication in tumor cells was confirmed by using GFP expressed under the virus MLP promoter. Upregulation of IFNγ and Granzyme B in culture media indicated a strong activation of T-cells via expression of the bispecific T-cell activator. Cytotoxic T-cell activation also led to dose-dependent cell killing in NSCLC spheroids as shown by life/death analysis. Having established this proof of concept for functionality of T-SIGn viruses in PDOTS, ongoing studies are evaluating the immunomodulatory activities of a series of T-SIGn viruses expressing human IL-12 with or without other cytokine/chemokines. Citation Format: Moataz Noureddine, Katy West, Elizabeth Isaacson, Sylvia Alarcon, Christopher S. Lathan, John Wain, David A. Barbie, Cloud P. Paweletz, Elena Ivanova, Brian R. Champion. A T-SIGn cancer gene therapy virus expressing an EpCAM-targeted bispecific T-cell activator stimulates T-cells and induces tumor cell death in patient-derived organotypic non-small cell lung cancer (NSCLC) spheroids ex vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1710.