PMID- 31753017 OWN - NLM STAT- MEDLINE DCOM- 20200721 LR - 20240210 IS - 2051-1426 (Electronic) IS - 2051-1426 (Linking) VI - 7 IP - 1 DP - 2019 Nov 21 TI - Bi- and tri-valent T cell engagers deplete tumour-associated macrophages in cancer patient samples. PG - 320 LID - 10.1186/s40425-019-0807-6 [doi] LID - 320 AB - BACKGROUND: Tumour-associated macrophages (TAMs) are often implicated in cancer progression but can also exert anti-tumour activities. Selective eradication of cancer-promoting (M2-like) TAM subsets is a highly sought-after goal. Here, we have devised a novel strategy to achieve selective TAM depletion, involving the use of T cell engagers to direct endogenous T cell cytotoxicity towards specific M2-like TAMs. To avoid "on-target off-tumour" toxicities, we have explored localising expression of the T cell engagers to the tumour with enadenotucirev (EnAd), an oncolytic adenovirus in Phase I/II clinical trials. METHOD: A panel of bi- and tri-valent T cell engagers (BiTEs/TriTEs) was constructed, recognising CD3epsilon on T cells and CD206 or folate receptor beta (FRbeta) on M2-like macrophages. Initial characterisation of BiTE/TriTE activity and specificity was performed with M1- and M2-polarised monocyte-derived macrophages and autologous lymphocytes from healthy human peripheral blood donors. T cell engagers were inserted into the genome of EnAd, and oncolytic activity and BiTE secretion assessed with DLD-1 tumour cells. Clinically-relevant ex vivo models (whole malignant ascites from cancer patients) were employed to assess the efficacies of the free- and virally-encoded T cell engagers. RESULTS: T cells activated by the CD206- and FRbeta-targeting BiTEs/TriTEs preferentially killed M2- over M1-polarised autologous macrophages, with EC(50) values in the nanomolar range. A TriTE with bivalent CD3epsilon binding - the first of its kind - demonstrated enhanced potency whilst retaining target cell selectivity, whereas a CD28-containing TriTE elicited non-specific T cell activation. In immunosuppressive malignant ascites, both free and EnAd-encoded T cell engagers triggered endogenous T cell activation and IFN-gamma production, leading to increased T cell numbers and depletion of CD11b(+)CD64(+) ascites macrophages. Strikingly, surviving macrophages exhibited a general increase in M1 marker expression, suggesting microenvironmental repolarisation towards a pro-inflammatory state. CONCLUSIONS: This study is the first to achieve selective depletion of specific M2-like macrophage subsets, opening the possibility of eradicating cancer-supporting TAMs whilst sparing those with anti-tumour potential. Targeted TAM depletion with T cell engager-armed EnAd offers a powerful therapeutic approach combining direct cancer cell cytotoxicity with reversal of immune suppression. FAU - Scott, Eleanor M AU - Scott EM AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Jacobus, Egon J AU - Jacobus EJ AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Lyons, Brian AU - Lyons B AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Frost, Sally AU - Frost S AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Freedman, Joshua D AU - Freedman JD AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Dyer, Arthur AU - Dyer A AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Khalique, Hena AU - Khalique H AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Taverner, William K AU - Taverner WK AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Carr, Alison AU - Carr A AD - Churchill Hospital, Oxford University Hospital NHS Trust, Oxford, OX3 7LE, UK. FAU - Champion, Brian R AU - Champion BR AD - PsiOxus Therapeutics Ltd., Abingdon, OX14 3YS, UK. FAU - Fisher, Kerry D AU - Fisher KD AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. FAU - Seymour, Len W AU - Seymour LW AUID- ORCID: 0000-0003-3825-0841 AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. len.seymour@oncology.ox.ac.uk. FAU - Duffy, Margaret R AU - Duffy MR AD - Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. LA - eng GR - 29106/CRUK_/Cancer Research UK/United Kingdom GR - C552/A17720/CRUK_/Cancer Research UK/United Kingdom GR - C5255/A20936/CRUK_/Cancer Research UK/United Kingdom GR - MRC_/Medical Research Council/United Kingdom GR - 17720/CRUK_/Cancer Research UK/United Kingdom PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20191121 PL - England TA - J Immunother Cancer JT - Journal for immunotherapy of cancer JID - 101620585 RN - 0 (Biomarkers) SB - IM MH - Adenoviridae/genetics MH - Biomarkers MH - Cell Communication/immunology MH - Cell Line, Tumor MH - Cytotoxicity, Immunologic MH - Gene Expression MH - Humans MH - Immunophenotyping MH - Lymphocyte Activation/genetics/immunology MH - Lymphocytes, Tumor-Infiltrating/*immunology/metabolism/pathology MH - Macrophages/*immunology/metabolism/pathology MH - Neoplasms/*immunology/metabolism/*pathology/therapy MH - Oncolytic Virotherapy MH - Oncolytic Viruses/genetics MH - Protein Binding MH - T-Lymphocyte Subsets/*immunology/metabolism/pathology MH - Transgenes MH - Tumor Microenvironment/*immunology PMC - PMC6873687 OTO - NOTNLM OT - Bispecific T cell engagers OT - Oncolytic virus OT - Tumour microenvironment OT - Tumour-associated macrophages COIS- LWS, BRC and KDF own equity or share options in PsiOxus Therapeutics (Oxford, UK), which is leading clinical development of EnAd and its derivatives. EDAT- 2019/11/23 06:00 MHDA- 2020/07/22 06:00 PMCR- 2019/11/21 CRDT- 2019/11/23 06:00 PHST- 2019/06/12 00:00 [received] PHST- 2019/11/06 00:00 [accepted] PHST- 2019/11/23 06:00 [entrez] PHST- 2019/11/23 06:00 [pubmed] PHST- 2020/07/22 06:00 [medline] PHST- 2019/11/21 00:00 [pmc-release] AID - 10.1186/s40425-019-0807-6 [pii] AID - 807 [pii] AID - 10.1186/s40425-019-0807-6 [doi] PST - epublish SO - J Immunother Cancer. 2019 Nov 21;7(1):320. doi: 10.1186/s40425-019-0807-6.