bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1610: Local delivery of anti CTLA4 mediates cDC1 dependent eradication of HNSCC with limited IRAEs in a preclinical model of oral squamous cell carcinoma
Authors: Gilardi Mara , Wang Zhiyong , Wu Victoria H. , Lopez-Ramirez Miguel Angel , Soto-Alvarez Fernando , Saddawi-Konefka Robert , Steffen Dana , Proietto Marco , Mikulski Zbigniew , Miki Haruka , Narayanan Jayanth Shankara , Molinolo Alfredo , Wang Joseph , Gutkind J. Silvio
Published: July 2021

Head and neck squamous cell carcinoma (HNSCC) ranks 6th in cancer incidence worldwide and has a five-year survival rate of only 63%. Despite advances in curative-intent therapies over the past three decades, rates of recurrence exceed 50% and long-term toxicities remain unacceptably morbid. Immunotherapies - principally immune checkpoint inhibitors (ICI) such as αPD-1 and αCTLA-41 antibodies which restore endogenous antitumor T cell immunity - offer the greatest promise for achieving durable response in HNSCC. However, the clinical application of ICI has been limited by immune-related adverse events (irAEs), which is a consequence of compromised peripheral immune tolerance after ICI therapy. Although irAEs are often reversible they can become severe, at best prompting premature termination of therapy or at worst becoming life-threatening. To address the off-target irAEs inherent to systemic ICI therapy, we developed a novel, local delivery strategy based upon an array of soluble microneedles (MN). Leveraging our recently reported syngeneic, tobacco-signature murine HNSCC model, we characterized the αCTLA-41 anti-tumor response as both CD8 T cell- and conventional dendritic cell type 1-dependent. When comparing αCTLA-4 therapy delivered in the traditional systemic format or with our local-MN delivery system, we found that while both routes of delivery led to >90% tumor responses, local-MN delivery achieved responses with lower total dosing while also limiting distribution of αCTLA-41 antibody from areas distal to draining lymphatic basins. Employing the previously described Foxp3-GFP-DTR GEMM developed for interrogation of murine irAEs, we found that local-MN protected animals from irAEs observed with systemic therapy. Taken together, our findings support the exploration of the microneedle array as a viable delivery strategy for ICI treatment in HNSCC.

Citation Format: Mara Gilardi, Zhiyong Wang, Victoria H. Wu, Miguel Angel Lopez-Ramirez, Fernando Soto-Alvarez, Robert Saddawi-Konefka, Dana Steffen, Marco Proietto, Zbigniew Mikulski, Haruka Miki, Jayanth Shankara Narayanan, Alfredo Molinolo, Joseph Wang, J. Silvio Gutkind. Local delivery of anti CTLA4 mediates cDC1 dependent eradication of HNSCC with limited IRAEs in a preclinical model of oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1610.
Abstract 1614: The effect of tumor mutation burden on immune checkpoint inhibitors in non-small cell lung cancer
Authors: Zhao Jie , Dong Yiting , Bai Hua , Duan Jianchun , Wang Guoqiang , Xu Jiachen , Wang Zhijie , Wang Jie
Published: July 2021

Backgroud: Tumor mutation burden (TMB) remains a promising but ambiguous biomarker for the efficacy of immune checkpoint inhibitors (ICIs)-based regimens. We conducted multifaceted systematic review and meta-analysis, and public cohort validation, to provide pooled evidence of the prediction value of TMB for ICIs in advanced non-small cell lung cancer (NSCLC).

Methods: Mirror-based meta-analysis balancing the confounding factors was applied in Part1, and Bayesian network meta-analysis was conducted in Part2. PubMed, Embase, and Cochrane Central were searched and abstracts from conference were reviewed. All randomized controlled trials (RCTs) that investigated the predictive value of TMB in advanced NSCLC patients receiving ICIs were included. Baseline characteristics, hazard ratios (HRs) with 95% confidence intervals (95% CIs) for progression-free survival (PFS) and overall survival (OS) stratified by TMB status were extracted. Furthermore, public cohorts of advanced NSCLC treated with ICIs with genomic sequencing were analyzed in Part 3.

Results: 10 RCTs covering 4443 patients and 5 public cohorts with 573 patients as validation were included. 9 RCTs were included in

Part1a. TMB-high subgroup exhibited significantly superior PFS than TMB-low subgroup (HR 0.56, 95% CI 0.47-0.67) in NSCLC treated with ICIs compared with chemotherapy, and such superiority was consistent in the preplanned subgroup analysis based on the line of therapy, regimen modality, test method of TMB and PD-L1 expression. 7 RCTs were included in Part1b. No significant difference of PFS or OS was observed between anti-PD-L1 and anti-PD-1 according to TMB status. 7 RCTs were included in Part2. Among all first-line regimens in TMB-high group, platinum-based doublet chemotherapy combined with anti-PD-1 was most likely to rank first for PFS (probability of ranking best 48.29%, surface under the cumulative ranking curve 0.83), anti-PD-L1 plus anti-cytotoxic T-lymphocyte A antigen-4 (CTLA-4) provided the most favorable OS (63.89%, 0.86), and platinum-based chemotherapy ranked worst for PFS (0.03%, 0.11) and OS (0.02%, 0.09). In Part3, TMB was validated to be an independent predictor, which could further distinguish beneficiaries of ICIs in those with PD-L1 expression less than 50%.

Conclusions: TMB could be used to identify beneficiaries of ICIs contained therapies and played a crucial role in determining the optimal first-line treatment among various available strategy for advanced NSCLC patients.

Citation Format: Jie Zhao, Yiting Dong, Hua Bai, Jianchun Duan, Guoqiang Wang, Jiachen Xu, Zhijie Wang, Jie Wang. The effect of tumor mutation burden on immune checkpoint inhibitors in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1614.
Abstract 1620: Efficacy and safety of ICIs in lung cancer patients with interstitial pneumonia
Authors: Fu Yan , Gong Fuyu
Published: July 2021

Background: ICIs has demonstrated efficacy against metastatic lung cancer. However, immune-related adverse events can occur, among which pneumonitis is relatively common. Lung cancer patients with interstitial pneumonia (IP) have a higher risk of pneumonitis associated with anticancer therapy. We hypothesized that the benefit of ICIs may outweigh the risks of pneumonitis in patients with lung cancer who have IP. We performed a pilot trial to evaluate the safety of ICIs in lung cancer patients with IP.

Methods: Previously treated, inoperable NSCLC patients with IP were enrolled. Patients received anti-PD-1/L1 as monotherapy or in combination with other agents, respectively.

Results: A total of 21 lung cancer patients were selected, including 15 (71.4%) male and 6 (28.6%) female with a median age of 62. None experienced drug related nonhematologic grade 3/4 or hematologic grade 4 adverse events in the 12 weeks following the initiation of ICIs treatment. Furthermore, none of the patients had pneumonitis of any grade. At the time of analysis, all patients were alive, and 11 had experienced a partial response.

Conclusion: ICIs therapy may be feasible in lung cancer patients with IP.

Citation Format: Yan Fu, Fuyu Gong. Efficacy and safety of ICIs in lung cancer patients with interstitial pneumonia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1620.
Abstract 1626: PMC309, a highly selective anti-VISTA antibody enhances T cell activation through blocking the interaction of T cells and myeloid derived suppressor cells (MDSC)
Authors: Park Cheon Ho , Byun Sang Soon , An Jin Yong , Ha Sun Hyung , Han Hye Rim , Kang Nu Ri , Park Beom Yong , Lee Eun Ah , Park Hyun Sun , Yoo Jin-San , Lee Weon Sup
Published: July 2021

TME (tumor microenvironment) consists of blood & lymphatic vessels, stromal cells, and immune cells such as lymphocytes, macrophages, and antigen-presenting cells (APC). Cellular interactions among various immune cell types within TME regulate tumor growth, metastasis, and resistance to cancer therapy. V-domain Ig suppressor of T cell activation (VISTA) is a negative checkpoint regulator highly expressed on tumor-infiltrating myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAMs) and VISTA blockade could enhance antitumor immunity in TME. PMC-309 binding to VISTA expressing cells is highly selective and the selectivity is maintained even in the low pH conditions that mimic TME. Binding of PMC-309 on MDSC cells enhances the secretion of IFN-γ, TNF-α, and IL-2 in Mixed Lymphocyte Reaction (MLR) settings. In in vivo study, PMC-309 suppressed tumor growth, which was further attenuated with an anti-PD1 antibody. The anti-tumor activity was associated with enhanced T cell activation, increased secretion of pro-inflammatory cytokines, and increased penetration of tumor-infiltrating leukocytes (TIL) into TME. Patients who became resistant to anti-CTLA-4 and anti-PD(L)1 antibody showed increased expression of VISTA, suggesting that anti-VISTA therapeutics can help to treat the patients who do not respond well to other immuno-oncology drugs. We are developing PMC-309 as a next generation immuno-oncology (IO) agent, which can convert immunologically cold into hot tumors as a mono- or combo- therapy with other IO agent.

Citation Format: Cheon Ho Park, Sang Soon Byun, Jin Yong An, Sun Hyung Ha, Hye Rim Han, Nu Ri Kang, Beom Yong Park, Eun Ah Lee, Hyun Sun Park, Jin-San Yoo, Weon Sup Lee. PMC309, a highly selective anti-VISTA antibody enhances T cell activation through blocking the interaction of T cells and myeloid derived suppressor cells (MDSC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1626.
Abstract 1627: Preclinical characterization of a novel CTLA-4-targeted ETB for direct Treg depletion
Authors: Khanna Swati , Howard Caleigh , Rabia Lilia A. , Aldana Alvaro , Zhao Jay , Chang Betty , Ramos Hilario J. , Iberg Aimee
Published: July 2021

Regulatory T cell (Treg) depletion enhances the anti-tumor efficacy of CTLA-4 targeted mAbs in preclinical models, and is a mechanism supported by retrospective clinical data analysis. In response to these findings, many next-generation CTLA-4 targeting therapeutics have been designed to increase Fc-mediated Treg depletion in the tumor microenvironment. CTLA-4-targeted engineered toxin bodies (ETBs) are designed to deplete Tregs in the tumor microenvironment (TME) directly and in a manner independent of Fc-mediated effector functions, offering a unique approach to CTLA-4 targeted therapy. ETBs, or engineered toxin bodies, are large molecule proteins consisting of an antibody fragment genetically fused to a proprietary de-immunized (DI) form of the Shiga-like toxin A subunit (SLTA). Once engaged to the specific cell surface target of interest, in this case CTLA-4, ETBs internalize, route to the cytosol, and permanently inactivate ribosomes through an irreversible enzymatic process. This results in cell death via apoptotic mechanisms.Here we describe the preclinical characterization of a lead candidate CTLA-4-targeted ETB. CTLA-4-ETB-A directly binds and specifically kills CTLA-4 positive cells in vitro and induces apoptosis of ex-vivo expanded Tregs. CTLA-4-ETB-A is designed to bind CTLA-4 in a manner unique from classic blocking antibodies and is not expected to have sustained blocking ability in vivo due to the relatively short half-life of an ETB compared to a neutralizing mAb. We predict this will allow for focused Treg depletion in the TME based on target expression levels, while sparing autoreactive T cell activation in the periphery. Utilizing human CTLA-4 knock in mouse syngeneic tumor models, we show that CTLA-4-ETB-A can reduce the % Tregs and increase the CD8/Treg ratio in the TME. Preclinical assessment of safety and pharmacodynamic signals are underway in cynomolgus studies.

Citation Format: Swati Khanna, Caleigh Howard, Lilia A. Rabia, Alvaro Aldana, Jay Zhao, Betty Chang, Hilario J. Ramos, Aimee Iberg. Preclinical characterization of a novel CTLA-4-targeted ETB for direct Treg depletion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1627.
Abstract 1646: Development of small-molecule HPK1 inhibitors to unleash tumor-specific T cell responses
Authors: Katibah George , Ohol Yamini , Bucher Cyril , Adusumilli Lavanya , Kaveri Deepika , Robles Omar , Sun Michael , Cho Cynthia , Milestone Heather , Ames Rachel , Jacobson Scott , Nebalasca Dan , Gomez- Guagua Justy , Sanchez Jerick , Grandcolas Molly , Wong Steve , Brovarney Martin , Ramana Chandru , Zaw Thant , Nguyen Lan , Tivitmahaisoon Parcharee , Ng Andrew , Ma Anqi , Gomez Blanca , Ko Michelle , Leger Paul , Jackson Jeffrey , Shibuya Grant , Shakhmin Anton , Bradford Delia , Xu Mengshu , Zibinsky Mikhail , Poon Daniel , Wustrow David , Kassner Paul , Brockstedt Dirk
Published: July 2021

Hematopoietic progenitor kinase 1 (HPK1) is an intracellular protein kinase that negatively regulates T cell signaling and proliferation. Upon T cell receptor (TCR) activation, active HPK1 phosphorylates the adaptor protein SLP76 in the TCR complex, recruiting the negative regulator 14-3-3 and targeting components of the TCR signaling complex for degradation. HPK1 thus limits the TCR signaling important for mounting an effective immune response against tumor cells. We are employing structure-guided drug design to develop potent small-molecule inhibitors of HPK1. Our compounds potently inhibit HPK1 in biochemical assays, reduce levels of phosphorylated SLP76 and concomitantly increase IL-2 production by Jurkat T cells. Importantly, our HPK1 inhibitors enhance cytokine production by human and mouse primary T cells above that observed with TCR activation alone. Treatment of mice with orally available HPK1 inhibitors results in increased activation of antigen-specific CD8+ T cells in vivo and decreased tumor growth as single agent and in combination with clinically relevant checkpoint inhibitor antibodies. Our work confirms the importance of HPK1 for T cell function and supports HPK1 as a promising next generation immuno-oncology target.

Citation Format: George Katibah, Yamini Ohol, Cyril Bucher, Lavanya Adusumilli, Deepika Kaveri, Omar Robles, Michael Sun, Cynthia Cho, Heather Milestone, Rachel Ames, Scott Jacobson, Dan Nebalasca, Justy Gomez- Guagua, Jerick Sanchez, Molly Grandcolas, Steve Wong, Martin Brovarney, Chandru Ramana, Thant Zaw, Lan Nguyen, Parcharee Tivitmahaisoon, Andrew Ng, Anqi Ma, Blanca Gomez, Michelle Ko, Paul Leger, Jeffrey Jackson, Grant Shibuya, Anton Shakhmin, Delia Bradford, Mengshu Xu, Mikhail Zibinsky, Daniel Poon, David Wustrow, Paul Kassner, Dirk Brockstedt. Development of small-molecule HPK1 inhibitors to unleash tumor-specific T cell responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1646.
Abstract 1647: CAPTIV-8: A prospective trial of atezolizumab using a multivariate model incorporating whole genome and transcriptome analysis
Authors: Titmuss Emma , Pender Alexandra , Pleasance Erin , Brown Scott , Grisdale Cameron J. , Topham James , Shen Yaoqing , Bonakdar Melika , Taylor Gregory A. , Williamson Laura , Mungall Karen , Chuah Eric , Mungall Andrew J. , Moore Richard A. , Lavoie Jean-Michel , Yip Stephen , Lim Howard , Renouf Daniel J. , Sun Sophie , Jones Steven J. , Holt Robert , Marra Marco A. , Laskin Janessa
Published: July 2021

Dramatic and durable responses to immune checkpoint inhibitors (ICIs) have been observed across multiple tumor types, but identifying the patients most likely to respond to these drugs remains challenging, particularly in the context of metastatic and pre-treated disease. Recent clinically approved biomarkers for patient selection are tumor agnostic, but currently all approved markers are evaluated independently. Through the Personalized Onco Genomics (POG) program at BC Cancer, we aimed to study the impact of evaluating multiple biomarkers in a tumor agnostic cohort. We performed whole genome and transcriptome analysis (WGTA) on fresh tumor biopsies from a heterogeneous pan-cancer cohort of 82 patients with advanced metastatic disease subsequently treated with ICIs. Established biomarkers, including tumor mutation burden (TMB) and CD8+ T cell scores, were able to distinguish responders in our advanced and pre-treated cohort. Additionally, we discovered that combining multiple biomarkers provided the best stratification of patients, suggesting a multifaceted approach, such as WGTA, may be suitable for more accurate identification of patients that may benefit from ICIs. As such, we have initiated a Phase II clinical trial, CAPTIV-8 (NCT04273061), which is distinctive in its use of WGTA to evaluate multiple markers including TMB, CD8+ T cell scores, an M1-M2 macrophage score and viral integration to select patients most likely to respond to atezolizumab. Clinical and genomic data prospectively collected from two hundred patients will be evaluated to test the efficacy of combining these biomarkers and identify additional biomarkers of response which can be used to guide treatment with ICIs.

Citation Format: Emma Titmuss, Alexandra Pender, Erin Pleasance, Scott Brown, Cameron J. Grisdale, James Topham, Yaoqing Shen, Melika Bonakdar, Gregory A. Taylor, Laura Williamson, Karen Mungall, Eric Chuah, Andrew J. Mungall, Richard A. Moore, Jean-Michel Lavoie, Stephen Yip, Howard Lim, Daniel J. Renouf, Sophie Sun, Steven J. Jones, Robert Holt, Marco A. Marra, Janessa Laskin. CAPTIV-8: A prospective trial of atezolizumab using a multivariate model incorporating whole genome and transcriptome analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1647.
Abstract 1652: Co-targeting distinct hallmark capabilities for therapeutic benefit in pre-clinical GBM models
Authors: Chryplewicz Agnieszka , Hanahan Douglas
Published: July 2021

Glioblastoma (GBM) is the most common primary tumor arising in the central nervous system (CNS). The currently approved standard of care has transient clinical benefit as GBM tends to be exceedingly aggressive. Despite pronounced efforts to identify novel therapies, curative options for GBM do not exist and the survival rate of diagnosed patients is very low. Therefore, there is an urgent need for new treatment strategies, and one approach would be to co-target and thereby disrupt distinct hallmarks of cancer, aiming to elicit sustained therapeutic responses. We have assessed this concept by combining a tricyclic antidepressant -imipramine - with drugs targeting VEGF-A ligand or VEGF-Receptor in mice bearing de novo GBM. All monotherapies were ineffective. In notable contradistinction, we found that combinatorial regimens significantly increased survival benefit and regressed established tumors. Investigation of the basis for the therapeutic efficacy revealed that combining the VEGF pathway inhibitor with imipramine hyperactivated autophagy to the level of eliciting cancer cell-intrinsic autophagy-associated cell death, whilst modifying the tumor vasculature to be more normal-like. In addition, imipramine downregulated an M2-like phenotype of tumor-associated macrophages and reprogramed them to express chemokines attracting otherwise rare CD8 T cells, which were demonstrably contributing to the observed efficacy. As such, these hallmark co-targeting combinations served to reprogram the GBM microenvironment from immunosuppressive to pro-inflammatory, thereby sensitizing the tumors to immune checkpoint blockade, as evidenced by enhanced responses when an anti-PD-L1 therapy was included in the mix. The results to be presented will elaborate a provocative new therapeutic approach for glioblastoma that has prospect to motivate clinical evaluation in this daunting form of human cancer.

Citation Format: Agnieszka Chryplewicz, Douglas Hanahan. Co-targeting distinct hallmark capabilities for therapeutic benefit in pre-clinical GBM models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1652.
Abstract 1666: Tumor-specificity of tumor-infiltrating CD8+ t cells determines the potential of immune checkpoint inhibitors in breast cancer
Authors: Kim Jee Ye , Lee Yong Joon , Jeon Seung hyuck , Nam Heejin , Jung Jae Hyung , Kim Seung Il , Shin Eui-Cheol
Published: July 2021

Tissue-resident memory CD8+ T cells (TRMs), marked by expression of CD103, are considered to play a key role as anti-tumor immune response in breast cancer. However, prognostic value of TRMs and heterogeneity in CD103+ TRMs of breast cancer in terms of tumor-specificity needs further understanding to establish immuno-therapeutic implications. Here, we isolated tumor-infiltrating CD103+TRMs in breast cancer samples and matched peripheral blood mononuclear cells (PBMCs) which were prospectively collected from 127 patients who underwent surgical resection between July 2016 and May 2020 at Severance Hospital, Seoul, Republic of Korea. Multi-color flow cytometry analyses were performed.CD103+TRMs consist of both tumor-antigen specific CD8+ T cells and bystander CD8+ T cells, such as viral antigen-specific CD8+ T cells. Dissection of CD103+TRMs with CD39 expression reveals a clonally-distinct subpopulation exhibiting tumor-antigen specificity and reactivity with transcriptionally and phenotypically exhaustive features. CD39+CD103+ TRMs were enriched in HER2 enriched and triple-negative breast cancer(TNBC) subtypes, but not in Hormone receptor(HR) positive/HER2 not enriched subtypes, implying that the role of tumor-infiltrating CD8+ T cells in eliciting anti-tumor immune response differ among molecular subtypes. In line with early-exhaustive features of CD39+CD103+TRMs, inhibition of either PD-1 alone or both PD-1 and CTLA-4 reinvigorate the proliferation and the cytokine production of CD8+ TILs in HER2 and TNBC subtypes. Our findings indicate that different immuno-therapeutic strategies should be considered to different subtypes of breast cancer.

Citation Format: Jee Ye Kim, Yong Joon Lee, Seung hyuck Jeon, Heejin Nam, Jae Hyung Jung, Seung Il Kim, Eui-Cheol Shin. Tumor-specificity of tumor-infiltrating CD8+ t cells determines the potential of immune checkpoint inhibitors in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1666.
Abstract 167: Multiomics profiling of BAP1 loss in uveal melanoma
Authors: Baqai Usman , Purwin Timothy , Bechtel Nelisa , Chua Vivian , Han Anna , Aplin Andrew E.
Published: July 2021

BRCA1 Associated Protein 1 (BAP1) is a tumor suppressor gene with identified mutations in various cancers including uveal melanoma (UM), malignant mesothelioma, renal cell carcinoma, and cutaneous melanoma. The protein forms multicomplexes with various transcription factors and cell cycle regulators. It also functions as a deubiquitylating enzyme primarily located in the nucleus and acts on histone 2A, leading to altered gene transcription. Recently, it was shown to play a role in apoptotic signaling, homologous-directed repair, and ferroptosis regulation. Over 90% of metastatic UM cases report loss-of-function BAP1 mutations. There is a strong association between loss-of-function BAP1 mutations, metastasis, and poor disease prognosis, the mechanisms for which remain unclear. Understanding the role of BAP1 in metastasis may help uncover therapeutic approaches and improve overall survival outcomes for metastatic UM patients. Here we used a multi-omics approach to investigate changes in gene expression in UM with BAP1 loss. Bioinformatics analysis using multiple UM patient and cell line data sets revealed upregulation of key cell-cell adhesion genes, CDH1, CADM1, and SDC2 with loss of BAP1. These adhesion proteins may be involved with facilitating collective migration or enable metastatic seeding. Together, these data prompt further investigation into the specific roles of BAP1 during the metastatic cascade in UM, from primary dissemination in the eye to seeding in the liver.

Citation Format: Usman Baqai, Timothy Purwin, Nelisa Bechtel, Vivian Chua, Anna Han, Andrew E. Aplin. Multiomics profiling of BAP1 loss in uveal melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 167.
Abstract 1674: WNT signal pathway activation correlates with innate resistant to immune checkpoint therapies in melanoma
Authors: Gong Fuyu , Bai Yuezong , Xie wenzhuan , Cui Chuanliang
Published: July 2021

Background: Immune checkpoint inhibitors targeting the programmed cell death-1 receptor (PD-1) improve survival in a subset of patients with melanoma. There are still lots of patients could not reach the clinical benefit, even though with the positive expression of the programmed cell death 1 ligand 1 (PD-L1). Here, we aimed to research the immune resistance mechanism in melanoma.

Methods: The genomic data and clinical data of the discovery cohort was obtained from The Cancer Genome Atlas (TCGA). The clinical data of validation cohort in melanoma treated by immunotherapy was retrospective collected. And tissue from patients with melanoma were performed to whole exome sequencing in a College of American Pathologists-certified and Clinical Laboratory Improvement Amendments-accredited lab.

Results: Activation of WNT signaling was inferred that somatic mutations or somatic copy number alterations in WNT signaling elements including APC, WNT1, WNT4, WNT6, WNT16, CTNNB1, BCL9L, SMAD3 and SMAD4. Two cohort have been enrolled in this study, the discovery cohort from TCGA, and the validation cohort from the Chinese patients with melanoma. The frequency of WNT pathway alterations from the TCGA cohort was 28.4%, and which was represented mutually exclusive molecular subsets. In TCGA cohort, activating alteration WNT signaling were associated with shorter median OS (22.5 vs 13.6 months, p=0.047, HR=0.61 (0.37-0.89)).

Conclusions: Mutations predicted to activate the WNT pathway were associated with innate resistance to immune checkpoint blockade in melanoma.

Citation Format: Fuyu Gong, Yuezong Bai, wenzhuan Xie, Chuanliang Cui. WNT signal pathway activation correlates with innate resistant to immune checkpoint therapies in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1674.
Abstract 1679: Innate immunity and cytokine signaling pathways drive resistance to HSV-1 oncolytic immunovirotherapy in glioblastoma
Authors: Monie Dileep D. , Correia Cristina , Zhang Cheng , Ung Choong , Vile Richard G. , Li Hu
Published: July 2021

Glioblastoma multiforme (GBM) is a particularly aggressive primary brain tumor that is relatively common in adults. The disease comes with a dismal prognosis, often with expected survival just over a year when treated with surgery, chemotherapy, and radiation. A promising addition to our GBM treatment arsenal are oncolytic viruses (OVs), a class of immunotherapy now in clinical trials. The most effective OVs home in on tumor cells, killing them and releasing tumor-associated antigens that elicit antitumor immunity. This effectiveness, however, varies depending on the cell state—a property that may be influenced by the composition of the extracellular matrix (ECM) of GBM. Cellular communication network factor 1 (CCN1) is found in the ECM of the majority of GBMs and is predictive of resistance to OVs, particularly those derived from herpes simplex virus type 1 (HSV-1). In this study, our aim is to understand how extracellular CCN1 alters the GBM intracellular state in a manner that confers resistance to OVs. We began by using our NetDecoder platform to build CCN1-specific prioritized protein-protein interaction (PPI) networks from published LN229 human GBM transcriptomic datasets. From this network, we identified 12 PPI edges that dominate the network flow in CCN1-high LN229 cells when compared to CCN1-low controls. The 21 unique nodes that comprise these binary PPI edges were extracted and subjected to downstream biological process overrepresentation analyses using Gene Ontology. We found that the cytokine-mediated signaling pathway (FDR = 4.2 x 10-11; enrichment ratio = 15.8) and the cellular response to cytokine stimulus (FDR = 3.1 x 10-9; enrichment ratio = 10.9) were highly enriched when mapped to these nodes. We conclude that CCN1, acting as a paracrine signal in the GBM tumor microenvironment, primes the cell to inhibit HSV-1 and other candidate OV replication prior to any virus interactions, thus contributing to immunovirotherapy resistance. While CCN1 and its cell surface integrin binding partners are ostensible drug targets for overcoming this resistance, pharmacologic interventions that target CCN1-specific high flow edges in our prioritized PPI network may be more effective.

Citation Format: Dileep D. Monie, Cristina Correia, Cheng Zhang, Choong Ung, Richard G. Vile, Hu Li. Innate immunity and cytokine signaling pathways drive resistance to HSV-1 oncolytic immunovirotherapy in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1679.
Abstract 1687: T cells are required to maintain anti-CD20-mediated NK cell responses in vitro
Authors: Wang Zhaoming , Weiner George J.
Published: July 2021

Purpose: Anti-CD20 monoclonal antibodies, beginning with rituximab (RTX), are a mainstay of therapy for B cell malignancies. Despite their remarkable clinical efficacy, many patients fail to respond or develop resistance to anti-CD20 containing therapy. A better understanding of the mechanisms by which anti-CD20 antibodies mediate their anti-tumor effects is critical if we are to build further on what is already a remarkable success story.

Experimental procedures: Various subsets of healthy donor peripheral blood mononuclear cells (PBMCs) were cocultured in vitro with Raji cells and RTX or trastuzumab (TRA) as a control antibody for up to 7 days. The number of remaining Raji cells, NK cells and phenotype of NK cells was determined.

Results: When unfractionated PBMCs were cultured with Raji cells for 1 week, RTX depleted Raji cells and enhanced NK cell numbers compared to TRA. In such cultures, RTX also induced changes in NK cell phenotype including a shift from CD56dim to CD56bright and increased expression of CD16, CD57 and KIR. These changes were dependent on T cells. Depletion of T cells, largely CD4, suppressed elimination of Raji cells, NK cell viability and the change in NK cell phenotype. Cell to cell contact was required, as the ability of T cells to support NK cell cytotoxicity, viability and phenotypic change was lost when T cells were separated from other cells in a transwell assay. T cell activation with anti-CD3/CD28 beads enhanced the ability of T cells to support RTX-mediated NK cell responses, with concentrations of activated T cells as low as 1% being adequate to provide T cell help to NK cells. Similar results were seen when obinutuzumab was used instead of RTX and when autologous B cells were used as target cells instead of Raji cells demonstrating the observed T cell effect was not secondary to an allogenic response by T cells to Raji cells.

Conclusion: In longer term in vitro culture, anti-CD20 induces lysis of target B cells, preserves NK cell viability, and induces CD56dim to CD56bright transition and CD16 recovery in a T cell dependent manner. This T cell help requires cell-to-cell contact with NK cells and is enhanced following T cell activation. Ongoing studies are exploring the precise mechanisms by which T cells support NK cells, and whether similar changes are observed in patients. These findings could lead to evaluation of a combination of anti-CD20 therapy and T cell activation as a strategy for overcoming resistance to anti-CD20 therapy.

Citation Format: Zhaoming Wang, George J. Weiner. T cells are required to maintain anti-CD20-mediated NK cell responses in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1687.
Abstract 1691: CD137 (4-1BB) costimulation of CD8 T cells is more potent when provided in cis than in trans with respect to CD3-TCR stimulation
Authors: Otano Itziar , Azpilikueta Arantza , Glez-Vaz Javier , Ellmark Peter , Fritzell Sara , Fernandez-Hoyos Gabriela , Nelson Michelle Hase , Alvarez Maite , del Carmen Ochoa María , Bolaños Elixabet , Cuculescu Doina , Jauregui Patricia , Sanchez Sandra , Etxeberría Iñaki , Rodriguez-Ruiz María E. , Sanmamed Miguel F. , Teijeira Alvaro , Berraondo Pedro , Melero Igancio
Published: July 2021

CD137 (4-1BB, TNFSFR9) costimulation provides antigen-primed T cells with increased survival, proliferation and effector functions as well as metabolic advantages. These immunobiological mechanisms are being harnessed for cancer immunotherapy with agonist CD137-binding and crosslinking-inducing agents that elicit CD137 intracellular signaling. In this study, side-by-side comparisons show that provision of CD137 costimulation in-cis with regard to the TCR-CD3-ligating cells is far superior to that provided in-trans in terms of T-cell activation, proliferation, survival, cytokine secretion and mitochondrial fitness in mice and humans. Cis ligation of CD137 relative to the TCR-CD3 complex results in more intense canonical and non-canonical NF-κB signaling and provides a more robust induction of cell-cycle and DNA damage repair gene expression programs. Superiority of cis versus trans CD137-costimulation is readily observed in vivo and is relevant for understanding the immunotherapeutic effects of CAR T cells and CD137 agonistic therapies currently undergoing clinical trials, which provide costimulation either in cis or in trans.

Citation Format: Itziar Otano, Arantza Azpilikueta, Javier Glez-Vaz, Peter Ellmark, Sara Fritzell, Gabriela Fernandez-Hoyos, Michelle Hase Nelson, Maite Alvarez, María del Carmen Ochoa, Elixabet Bolaños, Doina Cuculescu, Patricia Jauregui, Sandra Sanchez, Iñaki Etxeberría, María E. Rodriguez-Ruiz, Miguel F. Sanmamed, Alvaro Teijeira, Pedro Berraondo, Igancio Melero. CD137 (4-1BB) costimulation of CD8 T cells is more potent when provided in cis than in trans with respect to CD3-TCR stimulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1691.
Abstract 1692: A novel immunoregulatory role of tumor treating fields (TTFields) on macrophage polarization
Authors: Brant Boris , Voloshin Tali , Volodin Alexandra , Koren Lilach , Klein-Goldberg Anat , Zemer-Tov Efrat , Paz Rom , Giladi Moshe , Weinberg Uri , Palti Yoram
Published: July 2021

Introduction: Tumor Treating Fields (TTFields) therapy is a clinically applied anti-neoplastic treatment modality delivered via noninvasive application of low intensity (1-3 V/cm), intermediate frequency (100-500 kHz), alternating electric fields. In this study we investigated the potential of TTFields for regulating macrophage phenotype skewing, with or without lipopolysaccharide (LPS) and interferon-γ (IFN-γ) or IL-4 activation.

Methods: Bone marrow cells were flushed from the femurs and tibias of 5-8 week old Balb\C mice to generate bone marrow-derived macrophages (BMDMs). To study individual macrophage responses to TTFields, we profiled macrophages that were stimulated with LPS+IFN-γ (M1 polarization) or IL-4 (M2 polarization), followed by treatment with TTFields (150 kHz) for 24 hours. Flow cytometry was used to assess surface expression of F4/80 (a macrophage biomarker) and the activation markers that included major histocompatibility complex class II (MHC II), CD80, and inducible nitric oxide synthase (iNOS). A multiplexed secretion assay was used to measure the heterogeneity of the stimulated macrophages. We captured the secretion of 13 different proteins including CXCL1 (KC), IL-18, IL-23, IL-12p70, IL6, TNF-α, IL-12p40, free active TGF-β1, CCL22 (MDC), IL-10, IL-6, G-CSF, CCL17 (TARC) and IL-1β.

Results: TTFields treatment polarized IL-4 stimulated M2 macrophages to the M1 phenotype, as indicated by a significant increase in the percentage of CD80+MHC IIhigh cells. Treatment with TTFields of BMDMs that were either stimulated with IFN-γ and LPS (M1 phenotype) or had remained unstimulated increased the percentage of CD80+MHC IIhigh cells to a lesser degree. Moreover, treatment with TTFields significantly increased intracellular iNOS levels in M1 polarized BMDMs. In unstimulated BMDMs, application of TTFields resulted in significant increases in secretion of the pro-inflammatory cytokines CXCL1, IL-18, IL-23, IL-12p70, TNF-α, IL-12p40, CCL22, G-CSF, CCL17 and IL-1β. Also, a similar pattern was observed in cell supernatants of M1 and M2 stimulated BMDMs after TTFields application.

Conclusions: These results elucidate a novel immunoregulatory role of TTFields on macrophage polarization. Future studies will aim to focus on the mechanism governing phenotypic skewing of macrophages treated with TTFields and to explore the effect of TTFields on macrophage in the tumor microenvironment.

Citation Format: Boris Brant, Tali Voloshin, Alexandra Volodin, Lilach Koren, Anat Klein-Goldberg, Efrat Zemer-Tov, Rom Paz, Moshe Giladi, Uri Weinberg, Yoram Palti. A novel immunoregulatory role of tumor treating fields (TTFields) on macrophage polarization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1692.
Abstract 1696: Anti-tumor effects from simultaneous cancer and TAM targeting by 010DS-Zn
Authors: Chung Jinhyuk Fred
Published: July 2021

Direct clearance of immune-suppressive Tumor Associated Macrophages (TAM) is a less-explored cancer therapeutic approach. We developed a novel folate-ligand guided zinc-peptide complex 010DS-Zn for selective induction of parthanatos in folate receptor overexpressing targets that include many solid and blood cancer types, in addition to M2-like macrophages. Consistent with known parthanatos mechanism, its in vitro mode-of-action (MOA) tested against 4T1 murine breast cancer cell was characterized by specific and rapid PARP-dependent AIF translocation into nucleus that executed massive DNA fragmentation. This in vitro/ex vivo cytotoxicity was found highly consistent against the 90 blood and solid patient-derived cancer types tested. Further in vivo MOA studies against aPD-1 responder and non-responder syngenic cancer models showed 010DS-Zn to be effective against both, albeit at increased dosage in the MDSC enriched tumors. In the aPD-1 responder cancer model CT26, 010DS-Zn demonstrated robust T-cell immune response initiation, which was enhanced upon co-treatment with aPD-1 mAb. Regardless of the tumor-response in vivo, 010DS-Zn treatment produced robust TAM-reduction activity in dose-dependent manners. Collectively, 010DS-Zn presents new cancer immunotherapeutic potentials for enabling previously inaccessible 2-combination therapies for targeting 3 layers of immune-evasion: Tregs, TAM, and MDSC. Furthermore, its ability to directly clear M2-like macrophages presents opportunities-worth-investigation for treating the M2-like macrophage-driven severe SARS-CoV-2 autoimmune syndromes or its post-recovery heart-damages.

Citation Format: Jinhyuk Fred Chung. Anti-tumor effects from simultaneous cancer and TAM targeting by 010DS-Zn [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1696.
Abstract 1698: Cardiovascular adverse events associated with immune checkpoint blockade: analysis of FDA-adverse events database
Authors: Castrillon Jessica A.
Published: July 2021

Background: Modern therapies in oncology have increased cancer survivorship, as well as the incidence of de novo cardiovascular events. While immune checkpoint inhibitors have shown significant clinical impact in several cancer types, the frequency of immune related adverse events is common.

Methods: We performed big data analytics on the FDA Adverse Events Reporting data of immunotherapy compared to chemotherapy adverse cases from January 2010- March 2020. We identified 90, 740 adverse event reports in both treatment groups. Myocarditis was significantly associated with patients receiving anti-PD-(L)1, 23.86 (95% CI 11.76-48.42, P < 0.001) and combination immunotherapy, 7.29 (95% CI 1.03- 51.89, P < 0.001). Myocarditis was most common in non-small cell lung cancer, melanoma, and renal cell carcinoma. Heart failure was significantly associated in chemotherapy compared to PD-(L)1, 0.50 (95% CI 0.37- 0.68, P < 0.001), CTLA4, 0.08 (95% CI 0.03-0.20, P<0.001), and combination immunotherapy, 0.25 (95%CI 0.13-0.48). Additionally, we observe a sexual dimorphism towards males in cardiac adverse reports for arrhythmia, 0.81 (95%CI 0.75-0.87, P <0.001), coronary artery disease, 0.63 (95%CI 0.53- 0.76, P <0.001), myocardial infarction, 0.6 (95%CI 0.53 -0.67, P<0.001), myocarditis, 0.59 (95%CI 0.47- 0.75, P < 0.001) and pericarditis, 0.5 (95% CI 0.35- 0.73, P <0.001).

Conclusion: Our study provides the current risk estimates of cardiac adverse events in patients treated with immunotherapy. Understanding the clinical risk factors that predispose immunotherapy treated cancer patients to fulminant myocarditis is crucial in Cardio-Oncology management.

Citation Format: Jessica A. Castrillon. Cardiovascular adverse events associated with immune checkpoint blockade: analysis of FDA-adverse events database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1698.
Abstract 1699: Direct and indirect immune effects of CMP-001, a virus like particle containing a TLR9 agonist
Authors: Sabree Shakoora , Voigt Andrew , Weiner George J. , Blackwell Sue
Published: July 2021

Background: CMP-001, a virus-like particle (VLP) containing a TLR9 agonist encapsulated by the Qb capsid, is showing promise in early clinical trials when administered intratumorally. Prior work by our group has demonstrated the immunostimulatory effects of CMP-001 are dependent on generation of an anti-Qb antibody response which results in opsonization of CMP-001 by plasmacytoid dendritic cells (pDCs) and production of IFNa. The in vivo efficacy of CMP-001-mediated in situ immunization is T cell dependent. Here, we explore the mechanisms by which the initial effects of CMP-001 on pDCs can activate other cell populations that can contribute to development of an anti-tumor T cell response.

Methods: Uptake of CMP-001 by various cell populations was evaluated by flow cytometry. Gene expression by various immune cell subsets in response to CMP-001 treatment was measured by single cell RNA sequencing (scRNAseq) of normal donor human PBMCs. Additional in vitro experiments were conducted to evaluate direct and secondary effects of CMP-001 on various immune cell subsets.

Results: Anti-Qb antibody-coated CMP-001 were taken up extensively by monocytes with lower levels of uptake by B cells and pDCs. Antibody-coated CMP-001 induced upregulation of interferon-responsive genes and molecules by various cell types including CXCL10, PDL1, and IDO. Much of the impact of CMP-001 plus anti-Qb on monocytes was indirect and mediated by type I interferon. Expression by purified monocytes of PDL1 and IDO was increased in response to IFNa after treatment with CMP-001 plus anti-Qb whereas CXCL10 expression was decreased.

Conclusions: CMP-001 plus anti-Qb induces production of type I interferon by pDCs. Type I interferon has secondary effects on a variety of cell types including monocytes which produce cytokines such as CXCL10 that can potentially impact the development of an anti-tumor T cell response. Uptake of anti-Qb-coated CMP-001 by monocytes has little direct effect on the monocytes. However, uptake of these particles by monocytes does alter the monocyte's response to type I interferon and results in enhanced expression of IDO and PDL1, and suppressed expression of CXCL10, consistent with generation of an immunosuppressive phenotype. These findings shed light on the complexity of the immune response to CMP-001, and provide insight into potential pathways that may be targeted in conjunction with CMP-001 to further enhance the efficacy of this novel approach to immunotherapy.

Citation Format: Shakoora Sabree, Andrew Voigt, George J. Weiner, Sue Blackwell. Direct and indirect immune effects of CMP-001, a virus like particle containing a TLR9 agonist [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1699.