Abstract
Peripheral blood T cells can be genetically targeted against cancer using fusion receptors known as chimeric antigen receptors (CARs). Many preclinical studies have provided great encouragement for this approach. However, pioneering clinical trials have been less successful and identified poor T-cell survival in patients as a crucial limiting factor. To address this, what is needed is a system to achieve selective expansion of tumour-specific effector T cells, both in vitro and in vivo. Here, we describe such an approach using IL-4, a pharmaceutical that has been tested in cancer patients and which is normally a poor mitogen for T cells. A chimeric cytokine receptor named 4αβ was engineered in which the IL-4 receptor α (IL-4Rα) ectodomain was fused to the shared βc subunit, used by IL-2/IL-15. Addition of IL-4 to 4αβ-expressing T cells resulted in selective phosphorylation of STAT3/STAT5/ERK, mimicking the actions of IL-2 or IL-15. Using receptor-selective IL-4 muteins, partnering of 4αβ with γc was implicated in these findings. Next, human T cells were engineered to co-express 4αβ with CARs specific for two breast cancer targets: MUC1 or the extended ErbB family. These T cells exhibited an unprecedented capacity to undergo IL-4-dependent expansion in vitro and repeatedly destroyed breast cancer cultures, greatly exceeding the performance of IL-2-stimulated cells. Importantly, 4αβ-expressing T cells retained cytolytic specificity for target antigen and dependence upon IL-4 (or IL-2) for survival. We have also used this system to achieve rapid IL-4-driven ex vivo expansion and enrichment of CAR+ human T cells in bags (T-bags). Experiments were performed under closed and pseudo-good manufacturing practice conditions, scaling up for phase 1 clinical trials. T cells expanded in this manner demonstrate Th1 polarisation and potent tumour destructive activity, both in vitro and in vivo, in tumour-bearing SCID Beige mice. Together, these findings provide proof of principle for the development of pharmacologically regulated T-cell immunotherapy for breast and other cancers.
Highlights
The response rarely sustains long among the responders for Herceptin monotherapy treatment
We have provided a novel mechanism of acquired resistance to Herceptin in human epidermal growth factor receptor 2 (HER2)-positive breast cancer and have resolved the inconsistencies in the literature regarding the effect of Herceptin on HER2 phosphorylation
Using a range of biochemical and cell-biology techniques, we have shown that BRCA1 is modified by SUMO in response to genotoxic stress, and co-localises at sites of DNA damage with SUMO1, SUMO2/3 and the SUMO conjugating enzyme Ubc9
Summary
The response rarely sustains long among the responders for Herceptin (trastuzumab) monotherapy treatment. BRCA1 is strongly implicated in the maintenance of genomic stability by its involvement in multiple cellular pathways including DNA damage signalling, DNA repair, cell cycle regulation, protein ubiquitination, chromatin remodelling, transcriptional regulation and apoptosis Both pathological and gene expression profiling studies provide evidence that breast cancers with germline mutations in BRCA1 are different from non-BRCA1-related breast cancers. The vitreous humour is one of the few tissues in the body that is avascular and virtually acellular, and previous studies have indicated that opticin contributes to the maintenance of this state by inhibition of angiogenesis The aim of this present study is to investigate the effect and mode of action of opticin in suppressing tumour cell proliferation and migration in vitro in a panel of breast cancer cell lines and to establish its therapeutic efficacy in human breast tumour xenografts in vivo. Using receptorselective ligands (patent filed by MRC Technology) specific for the TRAIL death receptors, TRAIL-R1/TRAIL-R2, we have previously shown that primary leukaemic cells isolated from patients with chronic lymphocytic leukaemia can be selectively sensitized to apoptosis by combining an a histone deacetylase inhibitor (HDACi) with a TRAIL-R1-specific form of TRAIL/TRAIL-R1 mAb
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