bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2378: The triple-specific antibody KA-3003, targeting PSMA, CD28, and 4-1BB, is developed for the treatment of prostate cancer by enhancing T cell activity within the tumor
Authors: Wu Guojin , Guo Zhengcheng , Peng Hao , Hao Feng , Liu Tongtong , Ning Jinying
Published: March 2024

Immunotherapy, revolutionizing the treatment of advanced solid tumors by blocking PD1 signaling, has encountered a challenge in prostate cancer, exhibiting a low response ratio to anti-PD-1 therapy. Furthermore, cancer immunotherapy using 4-1BB agonists faces limited clinical development due to dose-limiting toxicity. Here, we developed a tri-specific antibody, KA-3003, targeting PSMA, CD28, and 4-1BB, with the goal of enhancing T cell activation in the tumor microenvironment. This antibody was created using our common light chain bispecific antibody discovery platform and nanobody antibody discovery platform with knob-into-hole technology. KA-3003, in IgG1 format, features mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. It contains two identical nanobodies at the C-terminal against 4-1BB, while binding to PSMA and CD28 with two Fabs at the N-terminal, sharing an identical light chain. KA-3003 exhibits high affinity for PSMA and relatively lower affinity for CD28 and CD137. In the presence of a low concentration of CD3 antibody to stimulate T cell activation, co-culture of tumor cells expressing PSMA with primary T cells isolated from human PBMC enhances T cell activation and proliferation. In PBMC humanized immunodeficient mouse tumor models, KA-3003 effectively suppresses the growth of 22Rv1 tumors with or without a PD1 antagonist antibody. Additionally, KA-3003 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature. KA-3003 shows neither aggregation nor degradation. In conclusion, the tri-specific antibody KA-3003, developed with our common light chain antibody discovery platform, stands out as a promising pre-clinical candidate drug for the treatment of prostate cancer.

Citation Format: Guojin Wu, Zhengcheng Guo, Hao Peng, Feng Hao, Tongtong Liu, Jinying Ning. The triple-specific antibody KA-3003, targeting PSMA, CD28, and 4-1BB, is developed for the treatment of prostate cancer by enhancing T cell activity within the tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2378.
Abstract 244: Patient-derived organoids: A pre-clinical model to assess infection and killing capacity of viral vectors for cancer therapy
Authors: Morales-Rodriguez Francisco , Sasso Maria Stella , Bezhaeva Taya , Bailey-Bucktrout Samantha , Lai Ka Wai , Gkogkou Foteini , Boj Sylvia
Published: March 2024

HUB’s patient-derived organoids (PDOs) are in vitro models that preserve tissue morphology and original cellular complexity. Additionally, PDOs are compatible with (high) throughput screening methods, enabling informed decision-making early in the drug development pipeline and significantly improving the odds of positive outcomes in clinical trials. Akamis Bio has developed experimental viral vector-based tumour gene therapies that have the potential to treat a variety of solid tumours by driving the expression of immunologically active biomolecules and therapeutic proteins hampering tumour immune evasion. These vectors are based on a replication competent, chimeric group B adenovirus backbone that selectively replicates and expresses transgene payloads in tumor cells, and additionally exerts oncolytic activity. To evaluate the efficacy of such a virus-based gene delivery strategy, HUB set up a proof-of-concept study to assess the propagation capability of Akamis Bio’s viral vectors in tumour PDOs. Intact PDOs from primary pancreatic tumours were infected with several viral loads, ranging from 0.1 viral particles per cell (PPC) to 100 PPC. The viral vector encoded a GFP reporter gene to identify infected cells using fluorescence imaging. The cultures were imaged daily for 14 days, allowing the assessment of cytotoxicity and infection efficiency and dynamics. Independently of PPC, infections always started in the exterior of PDOs in a few GFP-positive cells. The gradual increase over time in GFP-signal toward the interior of PDOs suggests the high likelihood of secondary infection events. Crucially, GFP intensity was correlated with cell death in PDOs, as evidenced by morphological features detected in brightfield images. Moreover, the infection dynamics were dose-dependent, as the GFP intensity peak arose later with decreasing PPC. These results show the capacity of HUB PDOs to study the infection dynamics of Akamis viral vectors. This pre-clinical platform permits rapid and efficient screening and dose evaluation for oncolytic virotherapies. Unique access to extensive tumour PDO biobanks with characterized genomic landscapes allows best-in-class stratification of treatment response based on tumour type and genetic heterogeneity.

Citation Format: Francisco Morales-Rodriguez, Maria Stella Sasso, Taya Bezhaeva, Samantha Bailey-Bucktrout, Ka Wai Lai, Foteini Gkogkou, Sylvia Boj. Patient-derived organoids: A pre-clinical model to assess infection and killing capacity of viral vectors for cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 244.
Abstract 2464: Defective NMD promotes aberrant intron retention in clear cell renal cell carcinoma
Authors: Zhou Mi , Giri Gilbert , Kim William Y. , Dominguez Daniel
Published: March 2024

Clear cell renal cell carcinoma (ccRCC) is the 8th most common cancer in the United States, constituting 75% of all kidney cancer cases. Clear cell RCC (ccRCC) along with melanoma has traditionally been viewed as an immunotherapy responsive disease with a storied history of immunotherapy treatments including high dose interleukin 2 (IL2), interferon, and allogeneic stem cell transplant. Indeed, RCC was one of the first tumor types to garner FDA approval for PD1 immune checkpoint inhibition (ICI). However, unlike melanoma, most RCC tumors do not have a high tumor mutational burden (TMB) to potentially explain their immunotherapy responsiveness. We and others have sought to explain this unanswered question and have demonstrated that non-canonical tumor associated antigens like endogenous retroviruses (ERVs) may in part explain ICI response in RCC. We have noted that ccRCC tumors have the highest level of retained introns (RI) across all TCGA tumors, that RI levels are secondary to suppressed non-sense mediated decay (NMD) activity, and that one can subset ccRCC into RI-high and normal-like tumors. Moreover, we have found that mTOR signaling plays a key role in regulating NMD and intron retention and that mTOR inhibition can promote intron retention. We hypothesized that these aberrantly retained introns could serve as a rich source of highly foreign, tumor associated neoantigens and that of retained intron neoantigens, the ones not observed in normal tissue would be the most immunogenic. We derived a so called “Neo-RI-antigen burden” that represents the burden of retained intron neoantigens not found in normal tissues and demonstrate that the Neo-RI-antigen burden of complete responders is numerically higher than those with partial response or progressive disease in a dataset of immunotherapy treated melanoma patients. Our work suggests the possibility of using NMD-targeting drugs as a potential therapeutic in combination with ICI to enhance the overall treatment response.

Citation Format: Mi Zhou, Gilbert Giri, William Y. Kim, Daniel Dominguez. Defective NMD promotes aberrant intron retention in clear cell renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2464.
Abstract 250: Sex differences in cancer stemness among individuals with early onset colorectal cancer
Authors: Aladelokun Oladimeji , Sumigray Kaelyn , Khan Sajid A. , Johnson Caroline
Published: March 2024

Since 1990, the overall incidence and mortality rates of late onset colorectal cancer (LOCRC ≥50 years) have been decreasing due to improvements in access to screening and available treatment options. However, the rates for early onset CRC (EOCRC ≤ 49 years) have steadily increased in men and women. Less than 30% of LOCRC patients present with late-stage tumors (clinical stages III or IV) at the time of diagnosis compared to 70% of EOCRC patients. Despite this, the cellular and molecular mechanisms underlying the incidence and stage are unclear, as are appropriate strategies for prevention of recurrence in men and women with EOCRC. Effective prognostic markers are therefore urgently needed. To address this issue, we performed a detailed bioinformatics analysis based on Gene Expression Omnibus database (GSE39582; n=585 patients), wherein we identified 7 prognostic biomarkers for EOCRC: KRAS, LGR5, CTNNB1, MYC, BMI1, CD44 and ASNS. Importantly, Kaplan Meier analysis revealed tumor onset at a younger age was significantly (p = 0.0082) associated with poorer 5-year survival in men with EOCRC only, after adjusting for KRAS status. CTNBB1 and CD44 transcript levels were higher in men with EOCRC versus men with LOCRC. Conversely, female EOCRC had a higher frequency of KRAS mutations (52.6%) compared to their LOCRC counterpart (38.8%), and an increased expression of markers of tumor stem cell and metabolic reprogramming including LGR5, MYC, BMI, and ASNS. A single CRISPR-Cas9 deletion of ASNS in HCT116 cell lines, a pre-clinical model of EOCRC, caused an inhibition of 3D spheroid formation compared to HCT116 ASNS wild type cells. In vivo study using a cell line derived R2G2 mouse xenograft model showed that ASNS disruption caused a reduction in tumor burden that was accompanied by low Lgr5 and Myc transcripts compared to the ASNS wild type group, indicating that ASNS may regulate cancer stemness. Together, this data suggests a unique molecular fingerprint for EOCRC and highlights sex-specific influences on cellular metabolism during EOCRC progression.

Citation Format: Oladimeji Aladelokun, Kaelyn Sumigray, Sajid A. Khan, Caroline Johnson. Sex differences in cancer stemness among individuals with early onset colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 250.
Abstract 252: Functional and lineage atlas of salivary gland regeneration charted by rapid in vivo gene targeting
Authors: Gan Qiwen , Ying Zhe
Published: March 2024

The crucial function of the salivary gland of keeping the oral cavity lubricated to facilitate breathing, swallowing, and lingual communication is often compromised following cancer radiotherapies. Due to the ultra-high radiosensitivity and low regeneration potential of the salivary epithelium, radiation-induced damage is largely permanent, representing a major clinical challenge. To solve this problem, we have developed a scalable rapid gene targeting system in the murine salivary gland using in-utero injection of lentiviruses. This allows us to transduce ectodermal progenitors of salivary glands with high efficiency and full randomness. Barcoded lentiviral lineage tracing suggests that every major salivary gland originated from a defined number of progenitors, each progenitor-derived clone has relatively equal expansion potential during development and equally contributes to regeneration post radiation challenge. This observation indicates that the major salivary glands of a single mouse can be used as a platform to study lineage dynamics or test up to ~2600 different genetic conditions during regeneration. With this robust approach in hand, we identified major barriers to salivary gland regeneration from among hundreds of differentially regulated signaling pathways and genes post-irradiation. Based on these discoveries, we are currently in the process of 1) Understanding the molecular mechanisms underlying the top regeneration barriers; 2) Dissecting the cell fate dynamics of salivary gland regeneration with or without regeneration barriers; and 3) Testing if we can restore the salivary gland in situ via combinatorial removal of regeneration barriers. Our work will provide unbiased functional and lineage roadmaps of post-irradiation salivary gland regeneration and potentially serve as the cornerstones of future therapeutic interventions.

Citation Format: Qiwen Gan, Zhe Ying. Functional and lineage atlas of salivary gland regeneration charted by rapid in vivo gene targeting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 252.
Abstract 2532: Deciphering multiple protein complexes in BCL2 family to measure apoptotic dependencies in acute myeloid leukemia
Authors: Lee Hongwon , Chun Changju , Choi Byungsan , Hong Saem , Lee Yunseo , Koh Youngil , Yoon Tae-Young
Published: March 2024

The BCL2 protein family controls apoptosis by shifting the dynamic equilibrium state of complex formation. BH3 mimetics disrupt this balance by disturbing the interaction of a specific anti-apoptotic protein, leading to the initiation of apoptosis. However, relying solely on molecular data for the specific anti-apoptotic protein can be challenging due to the functional redundancy within the BCL2 protein family and their complex interaction network. Therefore, comprehensive profiling information considering protein complexes is essential to determine apoptotic dependencies, particularly in a clinical context. In this study, we adapted a Single-molecule Protein Interaction Detection (SPID) platform that can assess levels of protein complexes in a quantitative manner. Out of the 47 metrics included in our Apoptosis Signaling 47 panel, we utilized 22 assays to measure apoptosis dependencies in acute myeloid leukemia (AML) cells obtained from 32 patients. By combining these metrics, we developed a predictive model for the ex vivo response to ABT-199 treatment, focusing on three key biomarkers: BCL2-BAX complex, BCL2-BIM binding potential, and BCLxl-BAK level. From a receiver operating curve (ROC) analysis, the model exhibited high accuracy with a value of 0.94 area under the curve (AUC). We further validated our model by comparing the predicted response to the therapeutic outcomes in 10 AML patients according to the 2017 ELN guidelines, and achieved 100% sensitivity (4 out of 4 identified correctly) and 83.3% specificity (5 out of 6 identified correctly). Overall, our platform provides an effective method to explore apoptosis dependencies in clinical samples based on the information regarding protein complexes within the BCL2 protein family. Three key molecular biomarkers can be translated into a gauge for predicting therapeutic outcomes of BH3 mimetics, suggesting an improvement of precision medicine in AML treatment.

Citation Format: Hongwon Lee, Changju Chun, Byungsan Choi, Saem Hong, Yunseo Lee, Youngil Koh, Tae-Young Yoon. Deciphering multiple protein complexes in BCL2 family to measure apoptotic dependencies in acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2532.
Abstract 2536: Multimodal stratification of predictive biomarkers in head and neck cancers: A focus on cytokine-based immunotherapy
Authors: Ramos Corinne , Ruez Richard , Delebecq Sandra , Senechal Victor
Published: March 2024

Background Immunotherapy, particularly cytokine-based therapy, has been gaining traction in the treatment of head and neck cancers. Cytokines are small proteins that play a crucial role in the immune response to cancer. However, not all patients respond to cytokine-based immunotherapies, and some may experience severe side effects. The ability to predict which patients are most likely to benefit from these therapies could greatly improve the efficacy and tolerability of treatment. In this context, the study of predictive biomarkers, such as the expression of immune checkpoint molecules like PD-L1 and TIGIT, and the profiling of cytokines within the tumor microenvironment, has become crucial. These biomarkers could provide valuable information about the patient's immune response to the tumor and their likelihood of responding to cytokine-based immunotherapies.

Method A multimodal approach to stratify predictive biomarkers in head and neck cancers was used. The methodology was founded on combining metabolic, transcriptomic, and proteomic data to offer a comprehensive understanding of potential biomarkers. The data from different modalities were integrated using bioinformatics and machine learning algorithms. This comprehensive dataset was analyzed to identify multimodal biomarker signatures that could predict patient responses to cytokine-based therapies.

Result Preliminary finding showed significant heterogeneity in the expression of PD-L1, TIGIT, and various cytokines across the tumor microenvironment. This underscored the complexity of head and neck cancers. Certain multimodal biomarker signatures, which included specific patterns of immune checkpoint molecule expression, cytokine profiles, and immune cell infiltration, correlated robustly with patient responses to cytokine-based therapies.

Conclusion Our study demonstrates the considerable potential of a multimodal stratification approach in deciphering the complexity of head and neck cancers and predicting responses to cytokine-based immunotherapies. By integrating metabolomic, transcriptomic, and proteomic data, we identified unique biomarker signatures that strongly correlated with therapy responses. This work underscores the invaluable role of integrated predictive biomarker profiles in enhancing the precision of immunotherapy.

Citation Format: Corinne Ramos, Richard Ruez, Sandra Delebecq, Victor Senechal. Multimodal stratification of predictive biomarkers in head and neck cancers: A focus on cytokine-based immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2536.
Abstract 2567: An analysis of proviral insertion site of Moloney murine leukemia virus, PIM1, kinase expression and clinical outcomes in renal cell carcinoma
Authors: Holder Sheldon L. , Lagos Galina , Carneiro Benedito A. , Mega Anthony , De Souza Andre , McKay Rana R. , Elliott Andrew , Nabhan Chadi , Graff Stephanie L.
Published: March 2024

Background: Wild-type Proviral Insertion Site of Moloney Murine Leukemia Virus 1 Kinase (PIM1) is a constitutively active serine/threonine kinase that inhibits apoptosis and promotes cell cycle progression, proliferation, angiogenesis, invasion, and migration. Due to constitutive activation, PIM1 is regulated at transcription and degradation. We have previously shown PIM1 protein levels are elevated in clear cell renal cell carcinoma (ccRCC) compared to normal kidney and that PIM1 inhibition induces tumor regression in pre-clinical models. Current approved therapies for ccRCC do not inhibit PIM1. We hypothesized that high PIM1 expression will adversely affect clinical outcomes in ccRCC.

Methods: Whole transcriptome sequencing (WTS) data in the Caris Life Sciences database were examined for PIM1expression and overall survival (OS; defined as time from diagnosis to last contact or death). We assessed PIM1 in primary and metastatic ccRCC, and the impact on survival in ccRCC and papillary RCC. Differentially expressed genes (DEGs) associated with high PIM1 were also determined.

Results: PIM1, in the highest quintile, was associated with a shorter OS (869 vs 1738 days; HR 2.629; CI 1.495 - 4.611; p<0.001; N=147) in ccRCC. PIM1 is enriched in metastatic (median 7.62 transcripts per million (TPM), CI 6.35 - 9.26) vs primary (median 5.07 TPM; CI 4.28 - 6.45; p=0.0025) RCC. Upregulated DEGs associated with high PIM1 are involved in the extracellular matrix. IL-6 expression, known to correlate with worse outcomes, was 6.5-fold higher in PIM1 high vs PIM1 low (13.2 vs 2.1 TPM, p<0.0001) RCC. High PIM1 was associated with poor survival following checkpoint inhibition (HR 3.714, 95% CI 1.339 - 10.303, p=0.007) and a trend towards poorer survival following mTOR inhibition and VEGF inhibition. PIM1 did not affect survival in papillary RCC.

Conclusions: Real-word data show that high PIM1 correlates with poorer survival in ccRCC but not in papillary RCC. This effect likely persists independent of treatment received. PIM1 enrichment in metastatic ccRCC, and associated DEGs, suggest that PIM1 influences the extracellular matrix to promote metastases. The correlation between IL-6expression and PIM1 supports our prior data that an IL-6/JAK/STAT/PIM1 pathway is involved in ccRCC.

Citation Format: Sheldon L. Holder, Galina Lagos, Benedito A. Carneiro, Anthony Mega, Andre De Souza, Rana R. McKay, Andrew Elliott, Chadi Nabhan, Stephanie L. Graff. An analysis of proviral insertion site of Moloney murine leukemia virus, PIM1, kinase expression and clinical outcomes in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2567.
Abstract 2607: Dual payload immunochemotherapy to treat CD276 positive cancers
Authors: Zhou Zhuoxin Zora , Zhang Jiashuai , Zhou Lufang , Liu Xiaoguang Margaret
Published: March 2024

The Cancer Genome Atlas (TCGA) dataset showed higher level of CD276 (B7-H3) transcript in multiple cancers, including triple-negative breast cancers (TNBCs), non-small cell lung cancers (NSCLCs) and other cancers, than normal tissues. Our immunohistochemistry staining of hundreds of patient tissue microarrays confirmed the high expression of CD276 surface receptor in >60% of TNBC and >70% of NSCLC while minimal or low expression in 33 normal organs or tissues. This study aims to develop and evaluate a novel treatment strategy, i.e. anti-CD276 mAb-dual payloads conjugate (DualADC), as immune-chemotherapy to treat CD276-positive TNBCs and NSCLCs. First, a new CD276-targeting monoclonal antibody (mAb) capable of delivering payloads and upregulating tumoral immunity was developed and engineered. Then, a new platform to concurrently conjugate both traditional cytotoxic payload and immunoregulating regent with one CD276 mAb (DualADC) was established. Our evaluations showed that this targeted therapy effectively killed multiple subtypes of TNBC and NSCLC, significantly upregulated immune functions in tumor microenvironment, and reduced tumor burden by up to 90-100% in seven animal models (including patient-derived xenograft). The post-treatment analysis using single-cell RNA sequencing, Luminex multiplex cytokine assay, whole blood, histology and histopathology analysis demonstrated an integrated anti-cancer mechanisms and minimal systematic toxicity. Altogether, our study suggested that the 276-DualADC could provide a promising targeted chemo-immunotherapy for CD276-postive cancer patients. In future, translational investigations will be performed to determine the toxicology, optimal dose, and treatment strategy, and the combination with other therapy will also be evaluated.

Citation Format: Zhuoxin Zora Zhou, Jiashuai Zhang, Lufang Zhou, Xiaoguang Margaret Liu. Dual payload immunochemotherapy to treat CD276 positive cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2607.
Abstract 2616: BCG033, a novel bispecific antibody-drug conjugate targeting PTK7 and TROP2, demonstrates preclinical efficacy against triple-negative breast cancer and other solid tumor xenografts
Authors: Yao Sufei , Shang Chengzhang , An Gao , Guo Chaoshe , an W. Frk , Yang Yi
Published: March 2024

Metastatic triple-negative breast cancer (TNBC) patients have poor overall survival, highlighting the need for novel treatments. Although the TROP2-targeting ADC sacituzumab govitecan recently received accelerated approval from the FDA for the treatment of patients with metastatic TNBC, the on-target toxicity of this single-target agent has limited clinical efficacy. We sought to improve the specificity and efficacy of future TNBC-targeted therapies by generating a bispecific antibody-drug conjugate (bsADC) targeting TROP2 and PTK7, another tumor-associated antigen (TAA) that is highly expressed in TNBC and correlates with poor prognosis and metastatic disease.

We previously generated fully human antibodies targeting PTK7 and TROP2 from Biocytogen’s fully human, common light chain antibody transgenic RenLite® mice, which were selected such that their monovalent antibodies exhibited reduced internalization profiles for improved tumor selectivity. These antibodies were then constructed into a bispecific antibody targeting PTK7 × TROP2, which demonstrated reactivity to human and cynomolgus monkey antigens and binding to multiple cancer cell lines, including TNBC, with high affinity. PTK7 × TROP2 bsAb also showed enhanced internalization in vitro compared with parental monovalent antibodies. Next, the PTK7 x TROP2 bsAb was conjugated to vcMMAE with a drug-to-antibody ratio (DAR) of 4 to generate a bsADC (BCG033). BCG033-vcMMAE demonstrated superior activity to benchmark and parental ADCs in a cell line-derived xenograft (CDX) TNBC model with low PTK7 expression. Here, we demonstrate that BCG033-vcMMAE ADCs also exhibited superior efficacy to benchmark ADCs in PDX models, including TNBC xenografts and NSCLC xenografts. We next tested the efficacy of the PTK7 x TROP2 bsAb conjugated to BLD1102, Biocytogen’s novel, proprietary linker/payload composed of a DNA Topo I inhibitor payload and a highly hydrophilic protease-cleavable linker, with a DAR of 8. BCG033-BLD1102 showed potent activity in a colorectal cancer PDX model in which benchmark ADCs were inactive, even at high doses.

In summary, BCG033 conjugates demonstrate promising preclinical efficacy in vivo, which ultimately could provide a new treatment option for TNBC and other solid tumors expressing PTK7 and TROP2.

Citation Format: Sufei Yao, Chengzhang Shang, Gao An, Chaoshe Guo, W. Frk an, Yi Yang. BCG033, a novel bispecific antibody-drug conjugate targeting PTK7 and TROP2, demonstrates preclinical efficacy against triple-negative breast cancer and other solid tumor xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2616.
Abstract 2627: PanCancer epigenetic regulators of lymphocyte activation states
Authors: Karpova Alla , Terekhanova Nadezhda V. , Chen Siqi , Jayasinghe Reyka G. , Houston Andrew , Caravan Wagma , Fields Ryan C. , Ding Li
Published: March 2024

Several immune cell types have been successfully targeted for immunomodulatory therapy; however, the efficacies of such therapies are hindered by incompatible immune cell activation states. CD8+ T-cell exhaustion is one of the most studied T-cell states in the context of cancer and was shown to limit checkpoint blockade efficacy. Although CD8+ T-cell exhaustion studies in mice showed this state is tightly regulated by chromatin accessibility of cis-regulatory elements (CREs) and transcription factor activation, the exploration of these mechanisms, their prevalence, and their specificity in human cancers remains limited. In addition, chromatin accessibility signatures of other lymphocyte (CD4+ and NK) states frequently found in solid tumors have not been carefully characterized in a pan-cancer setting. Here we introduce the first single-nuclei atlas of pan-cancer and disease-specific cis- and trans-regulatory elements in tumor infiltrating lymphocytes. We profiled ~140K T-cell and NK cell nuclei with snATAC-seq and snRNA-seq from 227 tumor and normal samples from eleven cancer types. We distinguished two major subpopulations among exhausted CD8+ T-cells: GZMK expressing (CD8+ GZMK+ Tex) and ITGAE+ tissue-resident (CD8+ Trm ex). CD8+ GZMK+ Tex was enriched in clear cell renal cell carcinoma, while CD8+ Trm ex was found in all other cancers. Both exhausted groups featured high motif accessibility and expression of NR4A1, NFATC2, and NFKB2 transcription factors (previously reported to regulate exhaustion), but differed in EOMES motif accessibility and gene expression. We have identified other lymphocyte subpopulations showing exhaustion signatures, including CD4+ follicular helpers (CD4+ Tfh), CD4+ regulatory cells (CD4+ Tregs), and weakly cytotoxic tissue-resident NK cells (trNK weak). All these subpopulations showed increased expression and motif accessibility of the NR4A1 transcription factor, highlighting its role in regulating dysfunctional states not only in CD8+ T-cells, but also in CD4+ and NK cells. Additionally, CD4+ Tfh and Tregs showed enhanced activity of NFKB1, NFKB2, and POU2F2, and trNK weak cells had increased activity of NR4A2 and NR2F2. To put our results into clinical perspective, we have collected cohorts of renal cancer, melanoma and triple-negative breast tumors treated with immunotherapy in clinical trial settings, and showed elevated GZMK expression in exhausted T-cells in responders compared to non-responders.

Citation Format: Alla Karpova, Nadezhda V. Terekhanova, Siqi Chen, Reyka G. Jayasinghe, Andrew Houston, Wagma Caravan, Ryan C. Fields, Li Ding. PanCancer epigenetic regulators of lymphocyte activation states [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2627.
Abstract 2642: KEAP1 mutation in lung cancer cells leads to increased immunosuppressive capability
Authors: Occhiuto Christopher John , Liby Karen T.
Published: March 2024

Considerable advances have been made in lung cancer therapies, but there is still an unmet clinical need to improve survival for lung cancer patients. Immunotherapies have improved survival, although only 20-30% of patients respond to these treatments. Interestingly, cancers with mutations in KEAP1, the negative regulator of the NRF2 cytoprotective pathway, are resistant to immune checkpoint inhibition and correlate with decreased immune cell infiltration. NRF2 is known for promoting an anti-inflammatory phenotype when activated in immune cells, but the study of NRF2 activation in cancer cells has not been adequately assessed. The overall objective of this study is to determine how lung cancer cells with constitutive NRF2 activity interact with the immune microenvironment to promote cancer progression and metastasis. To assess this, we generated CRISPR-edited mouse lung cancer cell lines (Lewis Lung Carcinoma/LL2) with knockouts (KO) of the KEAP1 and NFE2L2 genes. The transcriptomic profiles of 3 KEAP1 KO and 1 NRF2 KO cell lines were compared to the parental wildtype (WT) line using RNA-sequencing. On unsupervised hierarchical clustering of differentially expressed genes, the 3 KEAP1 KO cell lines clustered together and the NRF2 KO clustered with WT cells. Importantly, canonical NRF2 pathway-related genes were significantly increased in KEAP1 KO clones, but the same genes were either decreased or similar to WT in the NRF2 KO clone. We then used flow cytometry to evaluate immunosuppressive surface markers known to suppress T cell function when expressed on cancer cells. Importantly, PD-L1, CD155, CD80, and CD86 were increased in the KEAP1 KO lines compared to WT, but not in the NRF2 KO clone. In addition, the cytokine release profile was differentially regulated in the KEAP1 KO clones in a manner that could alter T cell recruitment and function. These results were also consistent with gene expression in the sequencing dataset. Finally, using an orthotopic allograft model, we completed a preliminary immunophenotyping study of lung tumors for WT, KEAP1 KO, and NRF2 KO cell lines. The activation status of CD8+ T cells and the ratio of CD8+/CD4+CD25+ T cells (a prognostic marker) were decreased in KEAP1 KO tumors. Taken together, these data suggest cancers with KEAP1 mutations may increase tumor growth through suppression of T cells.

Citation Format: Christopher John Occhiuto, Karen T. Liby. KEAP1 mutation in lung cancer cells leads to increased immunosuppressive capability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2642.
Abstract 2648: CD155 regulates cell growth and immune evasion in diffuse midline glioma
Authors: Tzaridis Theophilos , Eisemann Tanja , Andrade Augusto Faria , Hope Jennifer L. , Becher Oren , Jabado Nada , Bradley Linda M. , Adams Peter , Wechsler-Reya Robert
Published: March 2024

There is an unmet need for effective treatment strategies for diffuse midline glioma (DMG), a devastating brain tumour arising in children and young adults. While immunotherapy is emerging as a powerful approach for treatment of other cancers, clinical trials with immune checkpoint inhibitors have failed to show a survival benefit for DMG patients. In this study, we analysed the expression of known immune checkpoint molecules on the surface of human and murine DMG cells by flow cytometry and identified CD155 and B7-H3 as the most highly expressed checkpoint molecules, with minimal expression of others, including PD-L1 and PD-L2. These findings were confirmed in primary patient samples from pediatric brain tumours (gliomas, medulloblastomas and ependymomas). To test whether CD155 regulates susceptibility to CD8+ T cell killing, we cultured murine DMG cells expressing ovalbumin (OVA) with CD8+ T cells from OT-I mice, which express T cell receptors specific for OVA. shRNA mediated silencing of CD155 led to a strong increase in T cell-mediated killing. In vivo, adoptive transfer of OT-I T cells into OVA-positive DMG-bearing immuno-compromised mice resulted in delayed tumour growth, and this effect was enhanced when tumours lacked CD155. Strikingly, CD155-deficient DMG cells failed to grow at all in immuno-competent mice, and depletion of CD8 T cells allowed these tumours to grow, highlighting a role for CD8 T cells in rejection of CD155-deficient cells. In addition to its effects on susceptibility to T cells, CD155 also exerted cell-autonomous effects on tumour cells: silencing of CD155 led to induction of apoptosis of DMG cells in vitro and to delayed tumour growth in vivo, even in immune-compromised mice. These studies demonstrate that CD155 functions as an immune checkpoint and as a regulator of tumour cell survival in DMG, and suggest that targeting CD155 could be a valuable double-pronged therapeutic strategy for this devastating disease.

Citation Format: Theophilos Tzaridis, Tanja Eisemann, Augusto Faria Andrade, Jennifer L. Hope, Oren Becher, Nada Jabado, Linda M. Bradley, Peter Adams, Robert Wechsler-Reya. CD155 regulates cell growth and immune evasion in diffuse midline glioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2648.
Abstract 2711: A novel bispecific antibody to reprogram the immune suppressive GBM TME
Authors: Wong Thomas , Leu Jia-Shiun , Fan Xuejun , Kang Reece , Abdelfattah Nourhan , Leonard Fransisca , Zhang Ningyan , Yun Kyuson
Published: March 2024

GBM (glioblastoma) is the most common and aggressive primary brain tumor in adults. Immunotherapy is an emerging and promising treatment modality for GBM. Unfortunately, most immunotherapy trials have provided only modest benefit to GBM patients thus far. A significant barrier that limits efficacy of immunotherapy in GBM is the paucity of tumor infiltrating lymphocytes and abundance of immune suppressive myeloid cells. A critical step in enhancing the efficacy of immunotherapy for GBM requires approaches that enhance T cell infiltration and reprogram the myeloid cells to a more pro-inflammatory state.

S100A4 is a major regulator of stemness, epithelial-mesenchymal transition, and immunosuppression in glioma stem cells and a critical regulator of immune suppressive myeloid and T cell phenotypes in GBM. Targeting S100A4 in either glioma cells or stromal cells is sufficient to reprogram the tumor immune landscape and extend survival of glioma bearing mice, indicating that S100A4 is a promising immunotherapy target. Since S100A4 has both intracellular and extracellular function as well as cytokine-like function, we developed a S100A4 blocking antibody. While the anti-S100A4 antibody blocks breast cancer metastasis efficiently, it did not cross the BBB. Hence, we generated a bispecific S100A4-TfR antibody (BsA) that allows robust BBB penetration. Using ELISA, confocal immunofluorescent microscopy, and multiplexed flow cytometry, our preliminary results suggest that systemic administration of the S100A4-TfR BsA results in accumulation of BsA in the brain and glioma tissue, increased T cell infiltration and immune remodeling. Furthermore, the BsA is taken up by glioma cells and accumulates intracellularly, which is correlated with decreased nuclear SOX2 expression. These results suggest that S100A4-TfR BsA is a promising agent to treat GBM to reprogram the GBM immune landscape and reduce stemness. We are currently performing single cell RNA-sequencing to elucidate molecular and cellular changes induced by the bispecific antibody treatment in different cell types and performing long term survival analyses to evaluate its therapeutic potential.

Citation Format: Thomas Wong, Jia-Shiun Leu, Xuejun Fan, Reece Kang, Nourhan Abdelfattah, Fransisca Leonard, Ningyan Zhang, Kyuson Yun. A novel bispecific antibody to reprogram the immune suppressive GBM TME [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2711.
Abstract 2718: A novel TROP2-targeted immune stimulating antibody conjugate (ISAC) with potent anti-tumoral activtiy and accpetable safety
Authors: Chen Ye , You Fei , Zhu Chenchen , Xiong Yao , Li Li , Luo Nana , Zhou Shuaixiang , Wang Fushuai , Xu Chenyang , Fei Fan , Li Chang , Wang Jianglu , Xu Jinling , Xiong Huizhong
Published: March 2024

Immune stimulating antibody conjugates (ISACs) are a unique class of ADC in which antibodies recognizing tumor antigens are conjugated with immune agonists. ISACs target tumor tissue and specifically activate intra-tumoral myeloid cells, unleashing downstream immune response. Like the other immune agonists, balance between efficacy and safety remains a challenge for ISACs.

Here we describe a potential first-in-class TROP2 ISAC with rationally selected antibody and TLR7/8 agonist linker-payload. The anti-TROP2 antibody elicited robust ADCP of TROP2+ tumor cells by macrophages. In-vitro, TROP2 ISAC mildly activated myeloid cells only in the presence of TROP2+ tumor cells. In-vivo, the molecule potently suppressed tumor growth in different TROP2+ xenograft tumors, and effectively enhanced killing of an ADC. In terms of safety, the ISAC was tolerated in both WT and hTROP2KI mice, and, importantly, in monkeys. Taken together, our data demonstrate a novel TROP2 ISAC with outstanding efficacy and manageable safety profile, which may benefit patients with TROP2+ tumors.

Citation Format: Ye Chen, Fei You, Chenchen Zhu, Yao Xiong, Li Li, Nana Luo, Shuaixiang Zhou, Fushuai Wang, Chenyang Xu, Fan Fei, Chang Li, Jianglu Wang, Jinling Xu, Huizhong Xiong. A novel TROP2-targeted immune stimulating antibody conjugate (ISAC) with potent anti-tumoral activtiy and accpetable safety [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2718.
Abstract 2733: NB202: A bispecific anti-PD1/TIM-3 antibody for cancer immunotherapy
Authors: Dong Jinyu , Zhang Yu , Wang Binbin , Wang Dong , Bu Tingting , Ni Jie , Nayak Bishnu , Dong Xin
Published: March 2024

Despite the remarkable efficacy of PD-(L)1 therapy, a significant proportion of cancer patients fail to respond or develop resistance over time. Co-expression of T-cell immunoglobulin and mucin domain containing-3 (TIM-3) with PD-1 on primed T cells has been observed in patients exhibiting resistance to PD-1 blockade. Moreover, TIM-3 is also expressed on other immune cells, including NK and DC, and plays a negative regulatory role in these immune cells. Therefore, the dual blockade of PD-1 and TIM-3 holds potential for enhanced clinical benefits. NB202 is a bispecific anti-PD1/TIM-3 antibody that has been designed to optimize the therapeutic response of anti-PD1 therapy by maximizing TIM-3 blockade on antigen-experienced T cells, enhancing NK cell activity, and improving antigen presentation ability of antigen-presenting cells (APC). NB202 has demonstrated high affinity binding to human TIM3 and PD-1 in the low nanomolar range. Moreover, it can simultaneously bind to TIM-3 and PD-1 receptors through a trans-manner, suggesting its potent capacity to enhance the interaction between T cells and dendritic cells (DCs). In classic MLR (mixed lymphocyte reaction) and T cell stimulation assays, NB202 has exhibited superior efficacy compared to the combination of anti-PD1 mAb and anti-TIM3 monoclonal antibodies as it significantly enhances the secretion level of interferon-gamma (IFN-gamma), and particularly interleukin-2 (IL-2). Moreover, in an anti-PD1 resistant mouse model, NB202 has shown promising efficacy results.

Citation Format: Jinyu Dong, Yu Zhang, Binbin Wang, Dong Wang, Tingting Bu, Jie Ni, Bishnu Nayak, Xin Dong. NB202: A bispecific anti-PD1/TIM-3 antibody for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2733.
Abstract 2745: Sequential tracking of PD-L1 expression on circulating epithelial tumor cells (CETCs) in men with primary non-metastatic prostate cancer
Authors: Schott Dorothea , Pizon Monika , Pachmann Ulrich , Pachmann Katharina , Mäurer Matthias
Published: March 2024

Background: Radiotherapy (RT) is an essential component of multimodality therapy in the primary or postoperative treatment of prostate cancer with curative intent by preventing local recurrence and distant metastases, indicating its impact on residual occult tumor, such as circulating tumor cells. Immunogenic changes in cancer cells induced by RT can lead to adaptive up-regulation of PD-L1 expression. As immune checkpoint inhibition plays an increasingly important role in prostate cancer, radiogenic PD-L1 upregulation may be of therapeutic importance. The aim of this study was to determine PD-L1 status on CETCs before and during RT.

Methods: Peripheral blood samples were collected from 52 primary non-metastatic prostate cancer patients. CETCs were enumerated and analyzed for PDL-L1 expression prior to (baseline), 3 and 6 weeks after the start of RT using fluorescence scanning microscopy.

Results: PD-L1 expression was detectable in CETCs and localized in the membrane and/or cytoplasm. We found a correlation between PD-L1 status in CETCs and aggressiveness of cancer disease prior to RT. The frequency of PD-L1 positive CETCs depended on the grading and Gleason score of the primary tumor. Patients with a high Gleason score and G3 tumors had significantly more PD-L1 positive CETCs compared to patients with a low Gleason Score and G1 tumors. Moreover, patients in stage I/II had significantly less PD-L1 positive CETCs compared to patients in stage III/IV (mean 54.25 vs. mean 69.65; p<0.05). A higher number of PD-L1 positive CETCs were detected in patients who had radical prostatectomy before start of RT than in those who had no surgical intervention (mean 66.24 vs. mean 47.46; p<0.01). Interestingly, the fraction of PD-L1 positive CETCs decreased significantly during RT only in patients with G3 tumors and a high Gleason Score.

Conclusion: Our results indicated that PD-L1 in CETCs is closely related to the aggressiveness of the primary tumor and may be a co-factor associated with the progression of prostate cancer. PD-1/PD-L1 blockade combined with RT represents a novel and promising treatment strategy that could contribute to improve the treatment efficacy of prostate cancer.

Citation Format: Dorothea Schott, Monika Pizon, Ulrich Pachmann, Katharina Pachmann, Matthias Mäurer. Sequential tracking of PD-L1 expression on circulating epithelial tumor cells (CETCs) in men with primary non-metastatic prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2745.