Immuno-gene-therapy of prostate cancer

Immuno-gene-therapy against cancer Background/strategy: Immunotherapy in cancer patients is tasked with overcoming tumor cells that have escaped immunosurveillance. Here, we bypass tumor escape by retargeting host T cells with T cell receptors (TCRs) selected from two sources: i) Chimeric antigen-receptors (CARs) generated by combing the antigen binding region of an antibody with the intracellular regions of a TCR. ii) T cell clones from clinical responders after cancer vaccination. From long term survivors, we have identified high affinity TCRs that have arisen in vivo, recognize naturally processed antigens and mediate anti-tumor activity. Methods: TCR sequences are obtained from tumor-specific T cell clones. TCR/CAR sequences are cloned into vectors for retroviral or mRNA expression. Thereafter the TCRs/CARs are transduced or transfected to T cells. The functionality is tested in vitro and in mouse models. After establishing functional TCRs/CARs, we aim to test the constructs in phase I trials. Tumor resistance to cancer immunotherapy is investigated in patient samples, mainly with flow cytometry (in Oslo) or HLA gene analyses (Grenada). Current project status: In 2011, postdoc Jon Amund Kyte started the project by analyzing immunological data from long term survivors from our telomerase trials. He selected hTERT-specific TCRs for further studies, with regard to redirecting T-cells. He also wrote two articles reporting clinical and immunological data from the hTERT vaccine patients. Jon Amund Kyte was from July 2012 to July 2013 visiting researcher at Dr. Martin Pule’s lab, University College London. In London, Dr. Kyte cloned and characterized two hTERT-specific TCRs. Further, he started the development of a CAR against a novel cancer target. In this process, dr. Kyte learned a range of laboratory techniques that will be useful for our lab in Oslo. After returning to our Oslo lab Aug 2013, Dr. Kyte has continued to investigate the functionality of T cells redirected with the hTERT specific TCRs. He finds that both TCRs are highly potent and confer the desired specificity to transfected T cells. This work formed the basis for DOFI 14032; 2014, which in turn lead to a 9 million NOK Biotek grant from NRC for 2015-2017. The work has been presented at scientific meetings (CIMT, PIVAC) and is leading to an article that we expect to submit in 2016 (Kyte et al, manus in prep). Dr. Kyte has together with his previous MD/Master-student (forskerlinje) GL Hansen performed in depth characterisation of samples from the hTERT vaccine trials, focusing on regulatory cells countering the effect of T cell therapy and vaccination. This has lead to a paper published in 2015 (Cancer Immunology Immunotherapy 2015 Oct 26). Regarding the T-cells redirected with CARs, dr. Kyte was main supervisor for PhD-student Hilde Almåsbak. We have in 2012/2013 conducted animal studies that have produced interesting findings, suggesting that the redirected T-cells effectively and specifically kill tumor cells expressing CD19. Ms. Almåsbak’s PhD thesis was accepted June 2014. Dr. Kyte has written an article based on these data, published in 2015 (Gene Ther 2015 May; 22(5): 391-403). The project has also paved the way for a clinical trial that is under preparation in leukemia patients (protocol written by JA Kyte in 2014/2015). Dr. Kyte also has a collaborative project with Prof. Garrido's lab in Grenada, Spain. Here, the focus is to uncover mechanisms of tumor escape from immunotherapy, based on selected patients in the clinical studies that Dr. Kyte is involved in. This project has resulted in an article published Jan 2014 (del Campo, Kyte, Carretero et al Int J Canc Jan 2014). The article reports the immune escape of HLA class I-negative tumor cells and chronological sequence of appearance of tumor ß2m gene mutation in successive lesions obtained from a melanoma patient, receiving immunotherapy at our Oslo lab. The results may lead to novel cancer therapy.