Tumour Escape from CAR-T Cells

AbstractOver the past decade, CAR-T cells have emerged as one of the most powerful cellular immune therapy approaches in the battle against haematological malignancies. Nonetheless, similar to other immunotherapeutic approaches, tumour cells develop strategies to evade CAR-T cell therapy, often with the support of a highly immunosuppressive and protective tumour microenvironment. To date, antigen loss, immune dysfunction, exhaustion and (microenvironment-mediated) upregulation of antiapoptotic pathways have been identified as major modes of tumour escape from CAR-T cell therapy. This chapter will focus on our current understanding of these modes of immune escape from CAR-T cells

Reduced splenic uptake on 68Ga-Pentixafor-PET/CT imaging in multiple myeloma - a potential imaging biomarker for disease prognosis

Beyond being a key factor for tumor growth and metastasis in human cancer, C-X-C motif chemokine receptor 4 (CXCR4) is also highly expressed by a number of immune cells, allowing for non-invasive read-out of inflammatory activity. With two recent studies reporting on prognostic implications of the spleen signal in diffusion-weighted magnetic resonance imaging in patients with plasma cell dyscrasias, the aim of this study was to correlate splenic (68)Ga-Pentixafor uptake in multiple myeloma (MM) with clinical parameters and to evaluate its prognostic impact. METHODS: Eighty-seven MM patients underwent molecular imaging with (68)Ga-Pentixafor-PET/CT. Splenic CXCR4 expression was semi-quantitatively assessed by peak standardized uptake values (SUV(peak)) and corresponding spleen-to-bloodpool ratios (TBR) and correlated with clinical and prognostic features as well as survival parameters. RESULTS: (68)Ga-Pentixafor-PET/CT was visually positive in all MM patients with markedly heterogeneous tracer uptake in the spleen. CXCR4 expression determined by (68)Ga-Pentixafor-PET/CT corresponded with advanced disease and was inversely associated with the number of previous treatment lines as compared to controls or untreated smouldering multiple myeloma patients (SUV(peak)Spleen 4.06 ± 1.43 vs. 6.02 ± 1.16 vs. 7.33 ± 1.40; (P5.79 ((P<) 0.001). Multivariate Cox analysis confirmed SUV(peak)Spleen as an independent predictor of survival (HR 0.75;P= 0.009). CONCLUSION: These data suggest that splenic (68)Ga-Pentixafor uptake might provide prognostic information in pre-treated MM patients similar to what was reported for diffusion-weighted magnetic resonance imaging. Further research to elucidate the underlying biologic implications is warranted

On-target restoration of a split T cell-engaging antibody for precision immunotherapy

T cell-engaging immunotherapies are changing the landscape of current cancer care. However, suitable target antigens are scarce, restricting these strategies to very few tumor types. Here, we report on a T cell-engaging antibody derivative that comes in two complementary halves and addresses antigen combinations instead of single molecules. Each half, now coined hemibody, contains an antigen-specific single-chain variable fragment (scFv) fused to either the variable light (V-L) or variable heavy (V-H) chain domain of an anti-CD3 antibody. When the two hemibodies simultaneously bind their respective antigens on a single cell, they align and reconstitute the original CD3-binding site to engage T cells. Employing preclinical models for aggressive leukemia and breast cancer, we show that by the combinatorial nature of this approach, T lymphocytes exclusively eliminate dual antigen-positive cells while sparing single positive bystanders. This allows for precision targeting of cancers not amenable to current immunotherapies

IKZF1/3 and CRL4-CRBN E3 ubiquitin ligase mutations and IMiD resistance in multiple myeloma

The work was supported by the Deutsche Forschungsgemeinschaft (KFO216), the IZKF, the BTHA and the CDW Stiftung (KMK). UM was supported by a grant of the German Excellence Initiative to the Graduate School of Life Sciences, University of Würzburg.S

Supplementary Appendix. All-trans retinoic acid works synergistically with the γ- secretase inhibitor crenigacestat to augment BCMA on multiple myeloma and the efficacy of BCMA-CAR T cells

Supplement Figure 1: ATRA treatment does not affect the viability of myeloma cell lines. MM.1S, OPM-2 and NCI-H929 cells were treated with ATRA for up to 72 hours. Cell viability was measured by flow cytometry and 7AAD staining (n=6). Bar diagrams show mean values +SD.Supplement Figure 2: ATRA plus crenigacestat treatment enhance BCMA expression on myeloma cell lines. Bar diagram shows BCMA expression on OPM-2 cells (n=3) after treatment with 100 nM ATRA and/or 10 nM GSI crenigacestat for 72 hours. Bar diagram shows mean values +SD. P-values between indicated groups were calculated using unpaired t-test. *p<0.05, **p<0.01.Supplement Figure 3: ATRA treatment leads to increased BCMA transcripts in OPM-2 myeloma cells. BCMA RNA levels in OPM-2 were analyzed by quantitative reverse transcription PCR (qRT-PCR) assay after incubation with increasing doses of ATRA for 48 hours (n=3). Bar diagram shows mean values +SD. P-values between indicated groups were calculated using unpaired t-test. *p<0.05.Supplement Figure 4: ATRA treatment leads to enhanced BCMA expression on primary myeloma cells. Representative flow cytometric analysis of BCMA expression on primary myeloma cells that had been cultured in the absence or presence of ATRA at different concentrations for 72 hours. 7-AAD was used to exclude dead cells from analysis.Supplement Figure 5: ATRA treatment does not impair viability of primary myeloma cells. Viability of primary myeloma cells with or without 72 hours of ATRA treatment was analyzed by flow cytometry and 7-AAD staining (n=5 biological replicates). Bar diagram shows mean values +SD.Supplement Figure 6: sBCMA does not impair BCMA CAR T cell functionality. CD8+ BCMA-CAR T-cells were co-cultured with MM.1S target cells in absence or presence of 150 ng/ml of soluble BCMA. After 4 hours, cytotoxicity was evaluated by bioluminescence- based assay. Diagram shows mean values +/-SD.Supplement Figure 7: ATRA treatment does not increase shedding of sBCMA. sBCMA concentration in the supernatant of OPM-2 and NCI-H929 after incubation with increasing doses of ATRA was analyzed by ELISA. Cell lines were cultured at 1x106/well (n=3 technical replicates). Bar diagrams show mean values +SD, P-values between indicated groups were calculated using 2way ANOVA. n.s. = not significant, *p<0.05, **p<0.01.Supplement Figure 8: BCMA-CAR T-cells confer enhanced cytotoxicity against ATRA plus crenigacestat-treated OPM-2 cells in vitro. OPM-2 cells were incubated with 100 nM ATRA and/or 10 nM GSI for 72 hours or were left untreated. Cytolytic activity of CD8+ BCMA- CAR T-cells was determined in a bioluminescence-based assay after 4h of co-incubation with target cells. Assay was performed in triplicate wells with 5,000 target cells per well. Data are presented as mean values +SD (n=4 biological replicates). P-values between indicated groups were calculated using unpaired t-test. n.s. = not significant, *p<0.05.Supplement Figure 9: Patient-derived BCMA-CAR T-cells confer enhanced cytotoxicity against ATRA-treated MM.1S cells. MM.1S cells were incubated with 50 nM ATRA for 72 hours or were left untreated. Cytolytic activity of MM patient-derived CD8+ BCMA-CAR T-cells was determined in a bioluminescence-based assay after 4h of co-incubation with target cells. Data are presented as mean values +SD of triplicate wells. P-values between indicated groups were calculated using unpaired t-test. *p<0.05, **p<0.01.Peer reviewe

Cancer Immunotherapy with Cocktails of Human Monoclonal Antibodies

Humane oder humanisierte monoklonale Antikörper haben sich in den letzten zehn Jahren als Arzneimittel etabliert. Sie sind hochspezifisch und zeigen in ihrer Anwendung im Vergleich zu konventionellen Therapeutika viel weniger Nebenwirkungen. In den 80er Jahren gelang es am Pathologischen Institut der Universität Würzburg eine Reihe von humanen Antikörpern aus Patienten zu isolieren, die hochspezifisch mit malignen Zellen reagieren und diese sowohl in vitro als auch im experimentellen Tiermodel selektiv durch Induktion von Apoptose töten. Um die Wirkungsweise von monoklonalen Antikörpern in der Krebstherapie zu erhöhen, werden die meisten in Kombination mit herkömmlichen Methoden, wie Chemotherapie, eingesetzt. Die ideale Therapieform sind hinsichtlich der Nebenwirkungen sog. Cocktails aus verschiedenen monoklonalen Antikörpern. Allerdings sind die Studien hierzu noch wenig fortgeschritten. Das Ziel dieser Arbeit war es, in präklinischen Versuchsreihen den Einsatz verschiedener tumorspezifischer humaner monoklonaler Antikörper als Cocktail und in Kombination mit Chemotherapie zu evaluieren. Hierzu wurden neun Antikörper in 32 verschiedenen Antikörperkombinationen hinsichtlich ihrer Auswirkungen auf die in vitro Proliferation einer Pankreaskarzinom-Zellinie untersucht. In Immunfluoreszenz-Aufnahmen ließ sich zeigen, dass kombinierte Antikörper an unterschiedlichen Stellen an der Zelle binden, was eindeutig auf verschiedene Zielstrukturen hinweist. Einige werden dabei endozytiert, während andere auf der Zellmembran bleiben. Interessanterweise ließen sich Kombinationen identifizieren, deren antiproliferative Wirkung sowohl additiv als auch synergistisch ist, das heißt größer als die Summe ihrer Einzelaktivitäten. Wurden Antikörper mit Zytostatika (5-Flurouracil) kombiniert, so ließen sich ebenfalls synergistische Effekte beobachten. In FACS-Analysen zeigt sich ein gesteigertes Bindungsverhalten der Antikörper, wenn die Zellen mit 5-FU vorinkubiert wurden. Zusammenfassend bestätigen die Ergebnisse dieser Arbeit die Beobachtung, dass die Wirkung humaner monoklonaler Antikörper in Kombination mit Chemotherapie erhöht werden kann. Für die Zukunft humaner Antikörper als Therapiemittel gegen maligne Erkrankungen mag allerdings noch wichtiger sein, dass Antiköper in Cocktails tatsächlich synergistische Wirkung zeigen können.Cancer patients receiving antibodies as mono-therapy have benefited from these treatments. However, significant improvements could be made if the antibodies were used in combination with conventional chemotherapy. Having learned from the natural oligoclonal antibody response that cancer patients mount to their own tumours, we suppose that cocktails of monoclonal antibodies could be even more active in treating cancer. We have isolated a series of human monoclonal IgM antibodies from cancer patients, which bind to different tumor-specific surface receptors and induce apoptosis in vitro and in vivo. To study the antibody-mediated effects in cocktails, the antibodies were applied in different combinations to pancreas carcinoma cells and analyzed in cytotoxic assays. Depending on their target, it was found that some combinations showed a significant additive or synergistic killing effect, when compared to mono-therapy. We also investigated a combinatorial treatment with chemotherapy on pancreas and colon cancer cells and found that a pretreatment with 5-FU sensitizes the cancer cells to antibody treatment. Based on our own results and data from other laboratories, it is likely that the next phase of antibody immunotherapy will include cocktails of monoclonal antibodies

Inflation and rate base valuation / BEBR No. 793

Includes bibliographical references

A review on tumor heterogeneity and evolution in multiple myeloma: pathological, radiological, molecular genetics, and clinical integration

Recent research has dramatically advanced our understanding of the genetic basis of multiple myeloma (MM). MM displays enormous inter- and intratumoral heterogeneity, and underlies a clonal evolutionary process driven and shaped by diverse factors such as clonal competition, tumor microenvironment, host immunity, and therapy. Two main cytogenetic groups are distinguished: MM with recurrent translocations involving the immunoglobulin heavy chain locus and MM with hyperdiploidy involving the odd chromosomes. The disease virtually always starts with a preneoplastic prodromal phase-monoclonal gammopathy of undetermined significance-that variably progresses to symptomatic MM within a few months or many years. Tumor heterogeneity and its evolution in space and time have important consequences for the clinical management and outcome of MM patients. At diagnosis, spatial intratumoral heterogeneity poses a challenge for classification and risk stratification. During maintenance therapy, clonal evolution may complicate disease monitoring and promote drug resistance. Upon progression or transformation, identifying the dominant disease-driving neoplastic clones and elucidating their properties are key to tailor personalized therapy. In this review, we discuss tumor heterogeneity and clonal evolution in MM, integrating pathological, radiological, molecular genetics, and clinical data. Current and prospective classification schemes and prognostic parameters, incorporating new genetic and proteomic discoveries and advances in imaging, are highlighted. In addition, the roles of the tumor microenvironment, host immunity, and resistance mutations, and their effects on therapy, are discussed. An improved understanding of high-risk disease, tumor heterogeneity, and clonal evolution will guide future therapies and may ultimately lead towards a cure for MM