bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2249: Checkpoint inhibitor therapy after dendritic cell vaccination elicits tumor response in mesothelioma patients
Authors: Cornelissen Robin , Belderbos Robert , Aerts Joachim
Published: August 2019

In mesothelioma most patients do not have functional T cells present in the tumor. Therefore, PD-1/PD-L1 checkpoint inhibitor (CI) therapy is likely to induce an anti-tumor response in only a small portion of patients. Activated autologous dendritic cells (DCs) that have been directed against mesothelioma tumor cells have been shown to reinvigorate T cell responses. This T cell response that is induced is prone to be blocked by the tumor using the PD-1/PD-L1 mechanism.

Earlier, we published the results of three phase I/II trials in which patients were treated with DC immunotherapy as first line therapy of after completion of first line chemotherapy. 9 patients were subsequently treated with checkpoint inhibitor therapy in several trials and compassionate use programs. Six patients were treated with nivolumab, two with pembrolizumab and one patient was treated with combination treatment of nivolumab and ipilimumab. In all patients, the initial biopsy was stained for PD-L1 and TIM3, in five patients, repeat biopsy was done at time of progression. Radiological response was measured on CT scan using modified response evaluation criteria in solid tumors (RECIST). A radiological partial response was seen in three patients after PD-1 inhibition, stable disease was seen in five patients and one patients had progression of disease as best response on CI therapy, giving a disease control rate of 88%. No CTCAE grade 3-4 adverse events were seen. Updated adverse events, median PFS and OS will be presented at the meeting, as well as correlation of response with PD-L1 and TIM3 status.

We conclude that CI treatment after DC immunotherapy is safe and feasible. In addition, after induction of a T cell response, disease control could be achieved in all but one treated patient on subsequent CI therapy. This report is a proof of concept that the induced T cell response from DC immune therapy may be blocked by PD-L1 upregulation from the tumor which in turn can be targeted by CI.

Citation Format: Robin Cornelissen, Robert Belderbos, Joachim Aerts. Checkpoint inhibitor therapy after dendritic cell vaccination elicits tumor response in mesothelioma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2249.
Abstract 2260: Targeting PP2A with LB100 enhances efficacy of CAIX CAR-T cells against GBM
Authors: Cui Jing , Zhang Qi , Song Qi , Wang Herui , Dmitriev Pauline , Sun Mitchell , Rosenblum Jared S. , Yang Kaiyong , Kovach John , Gilbert Mark R. , Zhuang Zhengping
Published: August 2019

The need for novel therapies for glioblastoma multiforme (GBM) is well established. Chimeric antigen receptor (CAR)-engineered T cells represent a promising cancer treatment modality for treating GBM. However, CAR-T therapy has limitations, such as low penetration into solid tumors and short duration of CAR-T survival. Protein phosphatase 2A (PP2A) inhibition has been implicated in enhancing T cell anti-tumor activity. LB-100 is a novel, first-in-class, small molecule inhibitor of PP2A recently shown in a Phase I trial to be well-tolerated at doses resulting in stabilization of progressive solid tumors. We set out to overcome limitations of CAR-T therapy by activating the mTOR signaling pathway through inhibition of PP2A by LB-100. GBM highly expresses CAIX due to increased hypoxia signaling. Thus, antitumor CAIX-specific CAR T cells were developed and tested against GBM in vitro and in vivo. CAR-T cells displayed GBM cells cytotoxicity and increased IFN-γ, TNF-α, and IL-2 production. Intra-tumor injection of the CAR-T cells into an intracranial GBM xenograft mouse model efficiently suppressed the tumor growth. We found that PP2A inhibition by LB-100 further enhanced CAIX CAR-T activity and significantly prolonged mouse survival. Herein we demonstrate that CAIX represents a viable target for CAR-T cells and inhibition of PP2A enhances CAR-T efficacy against GBM. Targeting PP2A via inhibition with LB-100 may be a promising therapeutic strategy to improve CAR-T efficacy in other solid tumors.

Citation Format: Jing Cui, Qi Zhang, Qi Song, Herui Wang, Pauline Dmitriev, Mitchell Sun, Jared S. Rosenblum, Kaiyong Yang, John Kovach, Mark R. Gilbert, Zhengping Zhuang. Targeting PP2A with LB100 enhances efficacy of CAIX CAR-T cells against GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2260.
Abstract 2264: Synergistic combination of oncolytic virotherapy and immunotherapy for glioma
Authors: Tang Bingtao , Guo Zong Sheng , Bartlett David L. , Yan David , Schane Claire P. , Liu Jia , McFadden Grant , Shisler Joanna L. , Roy Edward J.
Published: August 2019

Oncolytic viral immunotherapy is a novel approach to cancer treatment. Viruses can directly kill cancer cells, provide antigens to dendritic cells to stimulate a T cell response, and make cancer cells express genes of immune-enhancing cytokines locally within the tumor microenvironment. We hypothesized that the combination of oncolytic virus with a local stimulus for activating tumor-specific T cells and an anti-immunosuppressant would improve treatment of gliomas. An oncolytic virus encoding IL15-IL15Rα (the T cell activating stimulus) and the prostaglandin synthesis inhibitor celecoxib (the anti-immunosuppressant) were combined with adoptive transfer of tumor-specific T cells. Two oncolytic poxviruses, vvDD vaccinia virus and myxoma virus, were each engineered to express the fusion protein IL15-IL15Rα and a fluorescent protein (YFP or tdTomato Red). Viral gene expression was tested in the murine glioma line GL261 in vitro and in vivo. Orthotopic GL261 tumors in immunocompetent C57BL/6 mice were treated with vvDD-IL15-Rα vaccinia virus or vMyx-IL15Rα-tdTr combined with other treatments, including vaccination with GARC-1 peptide (a neoantigen for GL261), rapamycin, celecoxib, and adoptive T cell therapy. We found that vvDD-IL15-Rα and vMyx-IL15Rα-tdTr each infected and killed GL261 cells in vitro. In vivo, NK cells and CD8+ T cells were increased in the tumor due to the expression of IL15-IL15Rα. Each component of a combination treatment contributed to prolonging survival: an oncolytic virus, the IL15-IL15Rα expressed by the virus, a source of T cells (whether by pre-vaccination or adoptive transfer), and prostaglandin inhibition all synergized to produce total elimination of gliomas in a majority of mice. vvDD-IL15-Rα occasionally caused encephalitis, but vMyx-IL15Rα-tdTr was safe and effective, causing a strong infiltration of tumor-specific T cells and eliminating gliomas in 83% of treated mice. All these facts suggest that IL15-IL15Rα-armed oncolytic poxviruses provide potent antitumor effects against brain tumors when combined with adoptive T cell therapy, rapamycin and celecoxib.

Citation Format: Bingtao Tang, Zong Sheng Guo, David L. Bartlett, David Yan, Claire P. Schane, Jia Liu, Grant McFadden, Joanna L. Shisler, Edward J. Roy. Synergistic combination of oncolytic virotherapy and immunotherapy for glioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2264.
Abstract 2268: Agonistic T cell non depleting ICOS antibody strongly enhances anti-tumor activity with CTLA4 blocking monoclonal antibody without exacerbating colitis
Authors: Coutzac Clélia , Jouniaux Jean , Vozy Aurore , Ballas Marc , Brett Sara , Yadavilli Sapna , Angevin Eric , Hoos Axel , Chaput Nathalie
Published: August 2019

Background: ICOS is a member of the CD28 superfamily mainly expressed on activated T cells. An up-regulation of ICOS+ T cells is observed in patients treated with ipilimumab. These findings prompt further studies examining the synergy between CTLA-4 blockade and ICOS stimulation in generating optimal anti-tumor T cell immunity.

Methods: Peripheral blood mononuclear cells (PBMC) were collected from French patients with metastatic melanoma and treated with ipilimumab at baseline (V1) and after 1-2 ipilimumab infusion and restimulated in vitro with anti-CD3 plus anti-human non-depleting agonist ICOS IgG4 isotype antibodies. T cell proliferation and cytokine secretion was determined after 24 and 48h incubation. For in vivo experiments, C57Bl/6 and BALB/c mice were inoculated subcutaneously with MC38 and CT26 tumor cell lines respectively. Mice received intraperitoneal injections of anti-CTLA4 or its isotype control along with anti-mouse ICOS or corresponding isotype at D7, D10 and D13 with tumor growth assessments three times a week.

Results: PBMC collected from patients that respond to anti-CTLA-4 mAb exhibited stronger activation of T cells at baseline compared to patients with poor benefit. Treatment with a non-depleting agonist ICOS IgG4 mAb was able to rescue T cell activation in PBMC from patients with poor benefit. Furthermore, ICOS IgG4 with concurrent TCR engagement favored IL-10 secretion in patients that do not develop colitis during ipilimumab treatment suggesting that these patients may be protected from colitis due to a stronger capacity to secrete IL-10 after ipilimumab blockade particularly when ICOS is stimulated. In both mouse tumor models, combination with agonist non-depleting ICOS mAb increased the anti-CTLA-4 tumor activity without any colitis development.

Conclusion: This study provides evidence in mice and in humans that non-depleting agonistic ICOS mAb may increase anti-CTLA-4 tumor activity particularly in patients that do not benefit from anti-CTLA-4 alone without exacerbation of colitis.

Citation Format: Clélia Coutzac, Jean Jouniaux, Aurore Vozy, Marc Ballas, Sara Brett, Sapna Yadavilli, Eric Angevin, Axel Hoos, Nathalie Chaput. Agonistic T cell non depleting ICOS antibody strongly enhances anti-tumor activity with CTLA4 blocking monoclonal antibody without exacerbating colitis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2268.
Abstract 2290: Expression pattern of androgen receptor (AR), splice variant 7 (AR-V7) and splice variant 567 (AR-567) in circulating tumor cells and paired plasma-derived exosomes in metastatic castration resistant prostate cancer
Authors: Strati Areti D. , Zavridou Martha , Bournakis Evangelos , Mastoraki Sophia , Lianidou Evi S.
Published: August 2019

INTRODUCTION: Androgen-receptor splice variant 7 (AR-V7)is a highly promising liquid biopsy predictive biomarker indicating primary or acquired resistance to novel androgen receptor signaling inhibitors in metastatic castration resistant prostate cancer (mCRPC). We present for the first time the expression pattern of AR-FL, AR-V7, and AR-567es at a quantitative level in circulating tumor cells (CTCs) and paired plasma-derived exosomes in mCRPC.

METHODS: We first developed and analytically validated a novel multiplex RT-qPCR assay for AR full length (AR-FL), AR-V7, AR-567es and AR-total. We then quantified the expression levels of AR-splice variants, CK-19 (epithelial marker) and B2M (reference gene) in EpCAM+ CTCs and paired plasma-derived exosomes isolated from peripheral blood (20mL) of 62 mCRPC patients and 10 healthy donors.

RESULTS: In CTCs AR-FL was detected in 57/62(92%),AR-V7 in 32/62(52.0%),AR-567es in15/62(24.2%) and AR-total in 56/62(90.0%). In paired plasma-derived exosomes, AR-FL was detected in 45/62(72.5%), AR-V7 in 4/62(6.5%), AR-567 in 2/62(3.2%) and AR total in 47/62(75.8%).CK-19 expression was detected in 18/62(29.0%) of CTCs and in 28/62(45.2%) of exosomes. In all cases AR splice variants were expressed at higher levels in CTCs than in paired exosomes, while AR-V7 was detected at higher percentages than AR-567es.

CONCLUSIONS: Our results reveal for the first time a remarkable heterogeneity on the expression levels of AR-FL, AR-V7 and AR-567es in EpCAM+ CTCs and paired exosomes between individual mCRPC patients. The clinical significance of this finding will be further investigated in large patient cohorts in respect to therapy response.

Citation Format: Areti D. Strati, Martha Zavridou, Evangelos Bournakis, Sophia Mastoraki, Evi S. Lianidou. Expression pattern of androgen receptor (AR), splice variant 7 (AR-V7) and splice variant 567 (AR-567) in circulating tumor cells and paired plasma-derived exosomes in metastatic castration resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2290.
Abstract 23: Small molecule targeting of gankyrin reduces cell migration and proliferation in certain cancers
Authors: Farrales Pamela , Muth Aaron
Published: August 2019

Introduction: Gankyrin is an oncoprotein involved in regulating numerous pathways important to cell growth, signaling, proliferation and death. The overexpression of gankyrin and subsequent increased protein-protein interactions have been identified as key to increased proliferation in a variety of cancers. Consequently, small molecules that bind to and disrupt these protein-protein interactions are promising therapeutic strategies for the treatment of certain cancers. The first small molecule binder of gankyrin, cjoc42, was recently developed and exhibited efficacy in inhibiting the gankyrin-26S proteasome interaction. The aim of this work is to determine the effects of cjoc42 and its derivatives on cell migration and proliferation in gankyrin-overexpressing cancers.

Methods: Wound healing and CyQuant proliferation assays were used to determine the ability of cjoc42 to inhibit migration and proliferation in the gankyrin-overexpressing cell lines A549, MDA-MB231 and Huh6 cells. A protein thermal shift assay was used to screen new cjoc42 derivatives for their ability to bind gankyrin. Western blot experiments will determine if binding of cjoc42 and its derivatives to gankyrin is the mechanism of action in cells.

Results: Cjoc42 demonstrated an ability to inhibit the migratory and proliferative activity of A549 and MDA-MB231 cells. While only a modest inhibition of migration was observed, cjoc42 exhibited a significant antiproliferative effect against these cell lines. Utilization of a protein thermal shift assay yielded cjoc42 derivatives with more potent gankyrin-binding ability. These compounds will be evaluated in-cellulo for their ability to inhibit cell migration and proliferation. Western blot experiments will confirm that gankyrin-binding of cjoc42 attributes to the anti-migration and anti-proliferative effects observed.

Conclusions: These studies show that cjoc42 directly inhibits cell migration and proliferation by inhibiting the interaction between gankyrin and the 26S proteasome. Consequently, this work provides background for the development of small molecule inhibitors as a gankyrin-mediated therapy for the treatment of lung, breast and liver cancers.

Citation Format: Pamela Farrales, Aaron Muth. Small molecule targeting of gankyrin reduces cell migration and proliferation in certain cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 23.
Abstract 2305: Tumor MUC1 glycoprotein-highly specific CAR T cells control triple-negative breast cancer
Authors: Zhou Ru , Yazdanifar Mahboubeh , Roy Lopamudra Das , Maher John , Mukherjee Pinku
Published: August 2019

Antibody-derived Chimeric Antigen Receptor (CAR) T cells have great success in reduction of liquid form of tumor, but not solid tumor. Our novel antibody TAB004 can specifically recognize the tumor form of MUC1 (tMUC1) while sparing the normal MUC1 in several subtypes of breast cancers including >95% of triple negative breast cancer (TNBC). In vivo delivery of TAB004 specifically accumulates in the xenograft TNBC tumor only. Therefore, we hypothesize that TNBC can be specifically targeted with TAB004-derived tMUC1-specific CAR T cells. A panel of 45 human breast cancer cell lines were tested for tMUC1 level, and 11 out of 13 TNBC cell lines showed higher frequency of tMUC1 expression compared to that on normal cells. We engineered a 2nd generation human CAR using TAB004 that was coupled to the CD28-CD3zeta, named as MUC28z CAR. MUC28z was well expressed on activated human T cells. Compared to their mock control, MUC28z CAR T cells retained higher CD25 and CD11c, particularly on CD8 T cells. The susceptibility of TNBC cells to MUC28z CAR T cell cytolysis was dramatic while still corresponding to their tMUC1 level. Only the tMUC1-specific MUC28z CAR T cells expressed and released large amount of IFN-gamma after antigen recognition on TNBC cells. However, IFN-gamma was only involved in the tumor killing by MUC28z CAR T cells at lower E:T ratio. The in vivo treatment of TNBC tumor by MUC28z CAR T cells dramatically controlled HCC70 TNBC tumor growth in a xenograft model. Taken together, our TAB004-derived MUC28z CAR T cells are very potent at killing TNBC tumor cells both in vitro and in vivo, which is very promising to provide a safe, effective and tumor antigen-specific novel immunotherapeutic intervention.

Citation Format: Ru Zhou, Mahboubeh Yazdanifar, Lopamudra Das Roy, John Maher, Pinku Mukherjee. Tumor MUC1 glycoprotein-highly specific CAR T cells control triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2305.
Abstract 2307: Preclinical evaluation of TC-210, a mesothelin-specific T cell receptor (TCR) fusion construct (TRuC™) T cells for the treatment of solid tumors
Authors: Ding Jian , Horton Holly , Shah Seema , Zieba Adam , Krishnamurphy Janani , Ashhurst Thomas , Menk Ashley V. , Baeuerle Patrick , King Nicholas J. , Delogoffe Gregory , Hofmeister Robert , Getts Daniel R.
Published: August 2019

Despite success in treating hematological malignancies, T cells expressing chimeric antigen receptors (CARs) have shown poor efficacy in solid tumor indications. The failure to initiate and elicit a complete TCR response is arguably a primary underlying factor preventing CAR-T cell success in solid tumor indications. Here, we present a novel T cell engineering platform: T Cell Receptor Fusion Constructs (TRuC™s), which target tumors independent of MHC. Unlike CARs, the constructs integrate into the TCR complex, harnessing the full potential of natural T cell activation, effector function and regulation. Here we describe preclinical evidence underscoring the efficacy of TRuC™-T cells re-programmed to target the solid tumor antigen mesothelin (TC-210).

TC-210 has shown robust anti-tumor activity in cellular assays and animal models of lung, ovarian and MPM cancers. In these studies, TC-210 was compared head-to-head against mesothelin-targeting CAR-T cells (MSLN CAR-T cells) bearing the same mesothelin binder expressed on TC-210. Mesothelin-dependent T cell activation, expansion and tumor clearance by TC-210 was faster than that observed with MSLN CAR-T cells. In a study using Renilla-luciferase-labelled MSLN-CAR T cells and TC-210, TC-210 migrated and accumulated at a faster rate in mesothelioma tumors than MSLN-CAR T cells. This migration pattern correlated with an increased level of chemokine receptors and number of TC-210 expressing these receptors, including CXCR3. TC-210 T cells also showed long-term functional persistence capable of preventing relapse in a mesothelioma model. Metabolic profiling of TC-210 versus MSLN-CAR T cells showed that the observed persistence may be related to the metabolic profile of TC-210 T cells. Unlike MSLN-CAR-T cells, TC-210 showed increased levels of oxidative phosphorylation and mitochondrial reserve, attributes associated with long-term memory T cells. Finally, systemic cytokine levels in animals treated with TC-210 were lower than those observed in MSLN CAR-T cell treated animals.

Together, these findings warrant the investigation of TC-210 in clinical trials as effective treatment for mesothelin-expressing tumors with potentially lower rates of adverse events.

Citation Format: Jian Ding, Holly Horton, Seema Shah, Adam Zieba, Janani Krishnamurphy, Thomas Ashhurst, Ashley V. Menk, Patrick Baeuerle, Nicholas J. King, Gregory Delogoffe, Robert Hofmeister, Daniel R. Getts. Preclinical evaluation of TC-210, a mesothelin-specific T cell receptor (TCR) fusion construct (TRuC™) T cells for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2307.
Abstract 2312: Anti-CS1 x anti-CD3 bispecific antibody (BiAb)-armed anti-CD3 activated T cells (CS1-BATs) specifically kill CS1+ myeloma cells and release type-1 cytokines
Authors: Huang Manley , Thakur Archana , Lum Lawrence G.
Published: August 2019

Although advances in multiple myeloma (MM) therapy such as stem cell transplantation and newly approved biological agents have shown promising results, MM remains a terminal disease. Thus, new strategies to eliminate or control MM cells are needed. Elotuzumab, a humanized monoclonal antibody approved for treatment of MM, targets myeloma cells expressing CS1/SLAMF7. We heteroconjugated anti-CD3 (OKT3) and elotuzumab to develop a BiAb, CS1Bi, to target activated T cells (ATC) to CS1+ MM cells. To examine the potential therapeutic activity of BATs against MM, we tested the ability of ATC armed with CS1Bi to bind to MM cell lines, specifically kill MM cells lines expressing different levels of CS1, and produce Th1 cytokines upon engaging MM tumor targets. Initial studies showed that CS1-BATs bound to MM cells by flow cytometry and specifically killed CS1+ targets as measured in a 6 hour 51Cr-release assay. Cytokine secretion by CS1-BATs vs. unarmed ATC (n=2) of interferon-γ (IFN- γ: 512 pg/mL vs. 260pg/mL), tumor necrosis factor-α (TNF- α: 450pg/mL vs. 110pg/mL), granulocyte-macrophage colony-stimulating factor (GM-CSF: 217 pg/mL vs. 135 pg/mL), macrophage inflammatory protein-1α (MIP-1α: 8250 pg/mL vs. 400 pg/mL), macrophage inflammatory protein-1β (MIP-1β: 14750 pg/mL vs. 600 pg/mL), and RANTES (3550 pg/mL vs. 2600 pg/mL) were induced when CS1-BATs were co-cultured with CS1+ cell line, L-363 for 24h at E:T of 25:1. A more sensitive quantitative flow cytometry-based cytotoxicity assay was developed based on comparing of the number of eFluor 450-labeled target cells pre- and post-incubation with either CS1Bi-BATs or unarmed ATC prepared from healthy donors, or culture media alone. The number of eFluor450+/7AAD- viable cells/unit volume post-incubation were compared to the number of viable cells in untreated wells to calculate the percent cytotoxicity. This assay reproducibly demonstrated significant killing of five MM cell lines by CS1-BATS (armed with 50ng CS1Bi/106 ATC at an E:T ratio of 1:1) ranging up to 60%, depending on the target line, (n=8). Between 78- 95% of MM.1S cells were eliminated at an E:T ratio of 3:1 (n=2). These data demonstrate the clinical relevance of this anti-MM strategy for use in a Ph1/II clinical trial in patients with relapsed and/or refractory MM.

Citation Format: Manley Huang, Archana Thakur, Lawrence G. Lum. Anti-CS1 x anti-CD3 bispecific antibody (BiAb)-armed anti-CD3 activated T cells (CS1-BATs) specifically kill CS1+ myeloma cells and release type-1 cytokines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2312.
Abstract 233: Bispecific HER2 ADC: Making more potent HER2 ADC by improving target internalization
Authors: Bay Andres Perez , Kalsy Anuj , Tiwari Shiwani , Luan Bo , Kunz Art , Chen Zhaoyuan , Zhang Li , Potocky Terra , Nittoli Thomas , Thurston Gavin , Daly Christopher , Andreev Julian
Published: August 2019

Trastuzumab-emtansine (T-DM1) targets the well-characterized breast cancer oncogene HER2, and has shown success in the clinic, but tumors expressing intermediate levels of HER2 remain resistant to T-DM1 therapy, apparently due to insufficient lysosomal trafficking of T-DM1. Here, we engineered bispecific HER2-DM1 conjugates that bridge HER2 with the rapidly internalizing receptor APLP2. The high affinity arm of HER2xAPLP2 bispecific antibodies mediates surface binding to HER2+ tumor cells (but not to HER2- normal cells). After binding to HER2, the low affinity APLP2 arm promotes antibody internalization and lysosomal degradation. The strength of the APLP2 arm allows for modulation of the degree of internalization, degradation and killing. In in vitro killing assays, HER2xAPLP2-DM1 were significantly more potent than T-DM1 in cell lines expressing high (IHC3+) and intermediate (IHC 2+) levels of HER2, albeit induced little or no killing in cell lines expressing low HER2 levels (IHC 1+). Monovalent APLP2-ADCs induced little or no killing in all cell lines tested. Selected HER2xAPLP2-DM1 conjugates had acceptable PK profile in APLP2 humanized mice while significantly outperforming T-DM1 in inhibiting growth of IHC2+ tumor xenografts. These data pave the way to generate clinical candidate ADCs that will improve on T-DM1. In addition, our study opens up a possibility to exploit internalizing proteins such as APLP2 in combination with bispecific antibodies to enhance efficacy of ADCs.

Citation Format: Andres Perez Bay, Anuj Kalsy, Shiwani Tiwari, Bo Luan, Art Kunz, Zhaoyuan Chen, Li Zhang, Terra Potocky, Thomas Nittoli, Gavin Thurston, Christopher Daly, Julian Andreev. Bispecific HER2 ADC: Making more potent HER2 ADC by improving target internalization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 233.
Abstract 2330: Preclinical evaluation of TC-110: CD19-specific T cell receptor (TCR) fusion construct (TRuC™) T cell for the treatment of hematologic malignancies
Authors: Horton Holly , Ding Jian , Shah Seema , Gierut Jessica , Thorausch Niko , Morath Anna , Shamel Wolfgang , Maus Marcela , Baeuerle Patrick , Hofmeister Robert , Getts Daniel R.
Published: August 2019

T cells expressing chimeric antigen receptors (CARs) have demonstrated clinical benefit in certain hematological malignancies albeit with disease relapse as well as side effect such as cytokine release syndrome. To overcome potential hurdles of CAR-T cells and other T cell receptor modalities, we have designed a novel T cell engineering platform. Specifically, we have generated T Cell Receptor Fusion Constructs (TRuC™) that fuse a binder domain to subunits of the T cell receptor. These constructs when introduced using lentiviral technology, integrate into endogenous TCR, reprograming T cells to target tumor antigen in a non-major histocompatibility complex (MHC) restricted fashion and harnessing the full spectrum of TCR signaling.

Here, we present the results of the preclinical evaluation of TC-110, a CD19-specific ϵ-TRuC™ variant. In vitro, TC-110 T cells are equally potent as CAR T cells in eliminating tumor cells, while producing less inflammatory cytokines. In preclinical mouse models of ALL and Burkitt’s lymphoma, TC-110 T cells demonstrate better efficacy than 2nd generation CAR-T cells bearing CD28 or 41BB co-stimulatory domains. Of note, the efficacy of TC-110 T cells, both in vitro and in vivo, is not dependent on co-stimulatory signal. Overall, we demonstrate the efficacy of TC-110 T cells both in vitro and in preclinical mouse models, indicating the clinical potential of TRuC™ platform for treating hematologic malignancy.

Citation Format: Holly Horton, Jian Ding, Seema Shah, Jessica Gierut, Niko Thorausch, Anna Morath, Wolfgang Shamel, Marcela Maus, Patrick Baeuerle, Robert Hofmeister, Daniel R. Getts. Preclinical evaluation of TC-110: CD19-specific T cell receptor (TCR) fusion construct (TRuC™) T cell for the treatment of hematologic malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2330.
Abstract 2331: Intratumor adoptive transfer of IL-12 mRNA transiently engineered anti-tumor CD8+ T cells
Authors: Etxeberria Inaki , Bolaños Elixabet , Teijeira Alvaro , Azpilicueta Arantza , Quetglas Jose Ignacio , Sanchez-Paulete Alfonso Rodriguez , Otano Itziar , Mancheño Uxua , Hervas-Stubbs Sandra , Inoges Susana , Garasa Saray , Alvarez Maite , Berraondo Pedro , Melero Ignacio
Published: August 2019

Adoptive T-cell therapy with TILs, CAR-T cells, and TCR-engineered T-cells is achieving remarkable clinical efficacy. Retroviral gene transfer of IL-12 into the T cell cultures markedly enhances efficacy but has shown unacceptable severe side effects in the clinic. To ensure transient gene transfer, tumor specific CD8 T cells were engineered by electroporation of mRNA encoding single chain IL-12 into OT1 and Pmel-1 TCR transgenic lymphocytes. Engineered T cells were injected intratumorally and achieved complete rejections not only of the injected lesion but also of distant concomitant tumors. Efficacy was further enhanced if a small dose of agonist anti-CD137 mAb was co-injected or if CD137-ligand mRNA was co-electroporated. Importantly, intratumor T-cell administration was more efficacious that the intravenous or subcutaneous routes. Therapeutic effects were dependent on IFNγ, cDC1 dendritic cells and endogenous T cells. Interestingly, treatment induced epitope spreading of the immune response to antigens not recognized by the adoptively transferred lymphocytes. Efficacy was also achieved when mouse TILs cultures were used and human TIL cultures can also be transiently IL-12 mRNA engineered. Intratumor release, transient IL-12 mRNA-engineering and repeated administration jointly constitute a safe, feasible and powerful cancer immunotherapy strategy.

Note: This abstract was not presented at the meeting.

Citation Format: Inaki Etxeberria, Elixabet Bolaños, Alvaro Teijeira, Arantza Azpilicueta, Jose Ignacio Quetglas, Alfonso Rodriguez Sanchez-Paulete, Itziar Otano, Uxua Mancheño, Sandra Hervas-Stubbs, Susana Inoges, Saray Garasa, Maite Alvarez, Pedro Berraondo, Ignacio Melero. Intratumor adoptive transfer of IL-12 mRNA transiently engineered anti-tumor CD8+ T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2331.
Abstract 2334: Intratumoral classical complement pathway promotes tumor growth in renal cancer
Authors: Daugan Marie , Roumenina Lubka , Noé Rémi , Petitprez Florent , Sautès-Fridman Catherine , Fridman Wolf H.
Published: August 2019

Objective: The complement system has been considered for long as anti-tumoral effector in the context of monoclonal antibody therapy. Nevertheless, recent studies highlighted a pro-tumoral effect of complement, acting on angiogenesis, tumor cells proliferation and immunosuppression. The kidney is capable to produce a whole spectrum of complement components. Nevertheless, the role of complement activation for the progression of renal cancer remains poorly understood. In the present work we address the presence of complement components and their impact on the clinical outcome of patients with clear cell renal carcinoma (ccRCC). In addition, we evaluate the tumor growth of complement proteins-expressing tumor cell lines in complement-deficient mice.

Methods: The production of complement proteins by RCC lines was measured by RT-qPCR and by western blot (WB). Their expression in the tumor tissue was evaluated by immunohistochemistry and multicolor staining by immunofluorescence (IF) on sections from paraffin embedded tumors. The capacity of RCC cells-produced proteins to activate complement was evaluated by ELISA and western blot. The presence of complement was evaluated by immunohistochemistry on tumor sections from 3 retrospective cohorts composed by primary ccRCC patients (over 300 cases total). Complement producing tumor cell lines were grafted in WT and classical complement pathway deficient mice and the tumor growth was followed.

Results: We found that C1q is expressed in the ccRCC tumors by the infiltrating macrophages, having a particular phenotype. The remaining complement proteins are produced by the tumor cells. A dynamic interaction between the complement proteins produced by the tumor cells and the immune microenvironnement led to a local activation of complement revealed in vitro and in situ. The high level of C1q and complement activation correlated with a poor prognosis for patients. Moreover, the tumor growth was reduced in C1q-/- and C4-/- mice.

Conclusion: Early steps of the classical complement pathway can be activated locally and are associated with a pro-tumoral effect in mice models and in patients with renal cancer.

Keywords: renal cancer; C1q; classical pathway

Citation Format: Marie Daugan, Lubka Roumenina, Rémi Noé, Florent Petitprez, Catherine Sautès-Fridman, Wolf H. Fridman. Intratumoral classical complement pathway promotes tumor growth in renal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2334.
Abstract 2343: Immunogenetics of cancer and aging
Authors: Williams RMichael , Yunis Edmond J.
Published: August 2019

Antigen altered idiotype regulates specific immune responses (Cell Immunol. 1978: 4). Mendelian segregation of a given +/- phenotype defines an immune response gene (Benacerraf, Nobel). Autoimmunity producing anti-self clones must be eliminated or specifically suppressed, so a large portion of the antigenic repertoire resembles allogeneic MHC molecules (Medawar, Nobel). We proposed that exposure to many different allogeneic HLA molecules could cause specific immune suppression within the repertoire of epitopes and that these blank spots or holes in the universe of target antigens eventually would overlap with specificities including targets for eliminating pathogens such as viruses or tumor antigens. Some "holes" become large enough to result in an acquired immunodeficiency syndrome (AIDS) The opposite is also possible (Allogeneic Effect, Transplant Rev. 1972, 12; 141). This requires viable cells and cytokines released by host and/or donor. IR-genes for tumor resistance localize to the MHC. Class I/II MHC genes (Cancer Res. 1982; 35:1586) and NK cell receptor ligands (J. Stem Cell Res. 2007), regulate adaptive and innate immunity. We examined the combination of HLA specificities and the alleles of ligands of receptors of NK cells in breast cancer patients, HIV non progressors, and centenarians in Mexico. Immunological evaluation (CD4+,CD8+,CD19+ & NK cells and quantitative IgM, IgG, & IgA in breast cancer (BCA) patients in California. Overall survival (OS) depended on specificities (idiotypes) and the regulation of innate and adoptive immunity. The BCA patients and centenarians did not have HIV infection. People with more CD4 cells, more NK cells and more IgG, survive longer than those with the opposite immune profile. The immune specificity repertoire has evolved to avoid fatal autoimmunity, all orchestrated by T regs via T-cell antigen receptors and variable regions of Ig. The antigen receptors (CAR-T) and Ig variable region antigen receptors (Jerne, Nobel) are idiotypes, Single amino acid (AA) changes become altered "antigens" of the history of the patient: environment (e.g., microbiome), vaccination (e.g., BCG), and virus infections (Sendai or CMV in mice, HIV and/or others like HPV in man). This is true for single AA changes in both mice (H-2 mutants) and man; NK cell receptor ligands (Thr v Met). The results show profound effects on survival. Data, including MHC and NK receptor ligand phenotypes, OS and immunological evaluation of patients/people will be presented. Immunogenetic profiles of cancer survivors and long lived individuals are similar to those of HIV long term non progressors. Our data support our Immunogenetic Theory of Cancer and Aging.

Citation Format: RMichael Williams, Edmond J. Yunis. Immunogenetics of cancer and aging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2343.
Abstract 2344: The cGAS-STING pathway is a therapeutic target in a preclinical model of hepatocellular carcinoma
Authors: Thomsen Martin K.
Published: August 2019

Activation of the STING pathway is currently being explored in cancer immune therapy. The first STING agonist tested was DMXAA, but failed in clinical trial, since it does not bind human STING. The second generation of STING agonists are cyclic di-nucleotides (CDNs), either the naturally produced 2’3’ cyclic GMP-AMP or derivatives, and many of these has proven to have high affinity for all common human variations of STING. In our work, we have focused on 3’3’-cyclic 3’3’-cAIMP (Invivogen) for analysis of anticancer activity in mice.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, and the incidence of HCC is increasing. We have used a mouse model of mutagen-induced HCC to explore the therapeutic usefulness of targeting the DNA-activated STING pathway in HCC. STING-deficient mice exhibited unaltered initial development of HCC, but had higher number of large tumors at late stages of disease. In the liver of STING-deficient HCC mice, we observed reduced levels of phospho-STAT1, autophagy, and cleaved caspase 3. These responses were activated in the liver by treatment with a cyclic dinucleotide (CDN) STING agonist. Importantly, CDN treatment of mice after HCC development efficiently reduced tumor size. Initiation of CDN treatment at an even later stage of disease to allow HCC detection by MR scanning, revealed that the majority of tumors regressed in response to CDN, but new tumors were detected, which were unresponsive to CDN treatment. Conclusion: modulation of the STING pathway impacts on development of HCC, and holds promise for use in treatment of this disease, most likely in combination with other immunomodulatory treatments such as PD1 inhibitors or with standard of care.

Citation Format: Martin K. Thomsen. The cGAS-STING pathway is a therapeutic target in a preclinical model of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2344.
Abstract 2346: Curcumin suppresses PhIP induced inflammatory protein expression in breast epithelial cells
Authors: Jain Ashok
Published: August 2019

PhIP (2-Amino-1-methyl-6-phenylimidazo [4,5-b] pyridine), a prominent mutagen/carcinogen is a heterocyclic amine found in meat cooked at high temperature and in tobacco. PhIP is known to induce liver, colon, skin, prostate, and breast cancer as evident from several in vivo and in vitro studies. Our previous studies have demonstrated that curcumin significantly inhibits PhIP-induced DNA adduct formation and DNA double-strand breaks with the concomitant decrease in reactive oxygen species (ROS) production via multiple molecular targets. We hypothesize that PhIP induced ROS production induces inflammatory proteins and co-treatment with curcumin would suppress the induced inflammation. Therefore, human breast epithelial cells (MCF 10A) were used to test the expression of inflammatory proteins. MCF 10A cells were treated with PhIP alone and in presence of curcumin. Untreated cells and treated only with curcumin served as control. Human Inflammation array (Ray Biotech) was used to analyze the expression of forty inflammatory proteins. Results show that the expression of twenty inflammatory proteins is induced in MCF 10 A cells when treated with PhIP as compared to the controls. Presence of curcumin reduces the induced expression of these twenty inflammatory proteins. However, three inflammatory proteins (IL-8, IL 12p40 and ICAM-1) showed a significantly higher level of expression with PhIP and curcumin co-treated cells as compared to cells treated with PhIP alone. It is shown that higher expression of IL-8, IL 12p-40 and ICAM-1 is involved in chemotactic factor involve in attracting the neutrophils, basophils; activation of T and NK cells which might be helping in coordinating the inflammation process. Hence the present study suggests that curcumin is a promising natural compound to revert the effect of PhIP induced inflammation.

Citation Format: Ashok Jain. Curcumin suppresses PhIP induced inflammatory protein expression in breast epithelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2346.
Abstract 235: Preclinical activity of an antibody drug conjugate targeting tumor specificmuc1 structural peptide-glycotope
Authors: Trombe Marc , Caron Anne , Tellier Alexia , Carrez Chantal , Guérif Stephane , Clavier Severine , Karst Nathalie , Saarinen Juhani , Satomaa Tero , Pitkänen Virve , Aitio Olli , Heiskanen Annamari , Fassan Matteo , Pinkas Jan , Baffa Raffaele , Blanc Veronique , Nicolazzi Celine
Published: August 2019

SAR566658 antibody drug conjugate (ADC) is a humanized DS6 (huDS6) antibody conjugated through a cleavable linker to the cytotoxic maytansinoid derivative DM4 that has been evaluated in the clinical setting. The purpose of our work was; 1) characterize the epitope targeted by anti DS6 on mucin1, 2) determine the prevalence of antigen expression in a patient population and 3) further explore preclinical activities of the ADC. Murine DS6 monoclonal antibody (muDS6) was generated from serous ovary adenocarcinoma immunization of immunocompetent mice. It specifically recognizes a MUC-1 tandem repeat domain in the context of cancer associated glycosylation. CA6-positive MUC-1 carries mucin-type O-linked glycans with α2,3-sialylated and β1,4-galactosylated termini, and antibody binding was abrogated by treating MUC-1 with specific glycosidases that remove either one of these glycan structures. However, the antibody did not bind to synthetic glycans modeled according to the major O-glycans of MUC-1. Our characterization of the peptide-glycotope leads us to conclude that tumor associated glycosylation is essential for the formation of the epitope on the peptide sequence of the MUC-1 tandem repeat domain. CA6 expression was evaluated by immunohistochemistry in paraffin embedded tumor tissue samples: 35.2% of breast cancer patients, 70,1% of ovarian cancer patients and 58,5% of bladder cancer patients have at least 30% of CA6 positive cells with an intensity of 2+/3+ in a multinational population-based study. In pre-clinical in vivo models, SAR566658 induced anti-tumor activity against CA6 positive tumor models of human pancreas, cervix and bladder cancer as well as and 3 Breast Patient-Derived Xenografts (PDX). Efficacy was correlated with MUC1-CA6 expression levels. In 3 additional models, SAR566658 showed anti-tumor activity that was more potent when compared to 3 conventional tubulin cytotoxic agents, docetaxel, vinorelbine and vinblastine.

Citation Format: Marc Trombe, Anne Caron, Alexia Tellier, Chantal Carrez, Stephane Guérif, Severine Clavier, Nathalie Karst, Juhani Saarinen, Tero Satomaa, Virve Pitkänen, Olli Aitio, Annamari Heiskanen, Matteo Fassan, Jan Pinkas, Raffaele Baffa, Veronique Blanc, Celine Nicolazzi. Preclinical activity of an antibody drug conjugate targeting tumor specificmuc1 structural peptide-glycotope [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 235.
Abstract 2350: Type I interferon suppresses tumor growth through activating the STAT3-granzyme B pathway in tumor-infiltrating cytotoxic T lymphocytes
Authors: Lu Chunwan , Klement John D. , Ibrahim Mohammed L. , Redd Priscilla S. , Zhou Gang , Liu Kebin
Published: August 2019

Type I interferons (IFN-I) have recently emerged as key regulators of tumor response to chemotherapy and immunotherapy. However, IFN-I function in immune cells in the tumor microenvironment is largely unknown. We determined that IFNα13 and IFNβ are selectively expressed in colon carcinoma tissues in vivo. Although IFNAR1 KO mice exhibited increased susceptibility to carcinogen and inflammation-induced sarcoma and colon tumorigenesis, IFNAR1-sufficient tumors grow significantly faster in IFNAR1 KO mice and in mice with IFNAR1 deficiency only in T cells, suggesting that IFN-I functions in T cells to enhance host cancer immunosurveillance. Surprisingly, unlike in an anti-viral immune response where IFN-I regulates T cell activation and clonal expansion, IFNAR1-deficient T cells exhibit no deficiency in generation of antigen-specific CTLs and IFNAR1-deficient CTLs infiltration level is similar as compared to that of WT CTLs in colon tumor-bearing mice. Gene expression profiling identified Gzmb as an IFN-I target gene in tumor-infiltrating CTLs and in antigen-specific CTLs in vivo. Mechanistically, we determined that IFN-I activates STAT3 that directly binds to the Gzmb promoter to activate Gzmb transcription in CTLs. IFN-I also regulates GZMB expression in human T cells, but IFNAR1 is not only significantly down-regulated in human colon carcinomas but also down-regulated in CTLs of human colon cancer patients as compared to normal colon and CTLs from healthy donors. Our data determined that IFN-I plays a more dominant role in CTLs than in tumor cells to execute its anti-tumor function, and doing so through activating the STAT3-granzyme B pathway in tumor-infiltrating CTLs.

Citation Format: Chunwan Lu, John D. Klement, Mohammed L. Ibrahim, Priscilla S. Redd, Gang Zhou, Kebin Liu. Type I interferon suppresses tumor growth through activating the STAT3-granzyme B pathway in tumor-infiltrating cytotoxic T lymphocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2350.