Genetic Retargeted Human T-cells for RCC Immunotherapy

Dana-Farber Cancer Inst, Boston MA

Investigators

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Abstract

[unreadable] DESCRIPTION (provided by applicant): Renal cell carcinoma (RCC) is the most prevalent malignancy within the kidney and the incidence is rising. Due to improved radiological evaluation, over 50% of the renal cancers are found incidentally. Despite the fact that these early diagnosed tumors are often confined to the kidney, around half of all patients diagnosed with kidney cancer will develop systemic disease. Metastatic disease has a poor prognosis and traditional treatment modalities like-radio-and chemotherapy show overall response rates of 2-6%. Various clinical observations have suggested that the immune system may be important in the control of RCC as evidenced by the 10-15% response to biological modulators such as IL-2 and the spontaneous remission of some patients with metastatic disease after primary nephrectomy. However, the low response rate has only reinforced the need to develop new therapies to treat this disease. The use of chimeric "immune" receptors is a novel approach to retarget T-lymphocytes to cancer cells. This is accomplished through stable plasmid transfection or transduction with retroviral vectors that encode an immune recognition molecule that consists of a surface bound human single-chain antibody genetically linked to transmembrane and cytoplasmic domains that are capable of inducing cell activation and cytotoxic activity after binding to a cancer cell expressing the target antigen. However, there have been several limitations to this approach including inefficient transfection/transduction, absence of concomitant co-stimulatory signaling required for optimal T-lymphocyte activation and a lack of systematic study to evaluate the importance of the antibody binding domain in terms of affinity, epitope specificity and capacity to induce internalization for successful targeting. In this pilot R21 application, we will perform a systematic study to define the importance of each of these parameters for the genetic retargeting of T-lymphocytes. Specifically, we will use our 27 billion human antibody phage display library to identify a panel of high affinity human single-chain antibodies (scFvs) against the RCC-associated antigen carbonic anhydrase IX (CA IX) and will characterize their binding affinity, epitope specificity, and ability to induce internalization of CA IX on RCC cell lines and primary RCC cells. Next, we will transduce human peripheral blood T-lymphocytes with our third generation self-inactivating (SIN) lentiviral vectors encoding a panel of anti-CA IX chimeric immune receptors. The chimeric receptors possess critical CD28 costimulatory sequences that result in sustained T-cell activation, cytokine secretion and potent cytotoxic activity after binding to tumor cells. The transduced cells will be expanded with artificial antigen presenting cells expressing both CA IX and CD80(B7.1) in the presence of IL-15 and tested for their tumor cell cytotoxic activity in vitro and, for the transduced cells expressing the most potent chimeric receptors, in vivo in SCID-beige mice bearing RCC xenografts. We will also evaluate the ability of transduced T-lymphocytes from RCC patients to lyse autologous primary RCC cells in vitro. The long term goal of these studies is to use these genetically retargeted human T-lymphocytes in human clinical trials as a novel and potent immunotherapy of RCC. [unreadable] [unreadable]