bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 6539: RNAi mediated silencing of STAT3 in tumor-associated immune cells induces robust anti-tumor effects in immunotherapy resistant tumors
Authors: Ganesh Shanthi , Kim Minju , Lee Jenny , Feng Xudong , Krishnan Harini Sivagurunatha , Rijnbrand Rene , Beaudry Amber , Lockridge Jennifer A. , Uttamsingh Vinita , Hanrahan John
Published: March 2024

Malignant tumors are often associated with an immunosuppressive tumor microenvironment (TME), rendering most of them resistant to standard-of-care immune checkpoint inhibitors (CPIs). Signal transducer and activator of transcription 3 (STAT3), a ubiquitously expressed transcription factor, has well-defined immunosuppressive functions in several leukocyte populations within the TME. Since the STAT3 protein has been challenging to target using conventional pharmaceutical modalities, we investigated the feasibility of applying systemically delivered RNA interference (RNAi) agents to silence its mRNA directly in tumor-associated immune cells. In preclinical murine tumor models, chemically stabilized acetylated small-interfering RNAs (siRNAs) selectively silenced Stat3 mRNA in multiple relevant cell types in TME and tumor-draining lymph nodes (TDLN), reduced STAT3 protein levels, and increased cytotoxic T-cell infiltration. In murine models of CPI-resistant tumors, RNAi-mediated Stat3 silencing resulted in tumor growth inhibition, which was further enhanced and resulted in tumor regressions in combination with CPIs. Our findings suggest that targeting STAT3 directly and reducing STAT3 protein in the suppressive immune cell populations in the TME and TDLN may overcome some of the current limitations of immunotherapy and be of therapeutic benefit especially for cancer patients who failed to respond to standard immunotherapy treatments alone. A human active STAT3 conjugate is currently in Phase 1 clinical trial for treatment of immunotherapy refractory cancer types (NCT06098651).

Citation Format: Shanthi Ganesh, Minju Kim, Jenny Lee, Xudong Feng, Harini Sivagurunatha Krishnan, Rene Rijnbrand, Amber Beaudry, Jennifer A. Lockridge, Vinita Uttamsingh, John Hanrahan. RNAi mediated silencing of STAT3 in tumor-associated immune cells induces robust anti-tumor effects in immunotherapy resistant tumors [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 6539.
Abstract 6573: Targeting DLK1, a Notch ligand, with an antibody-drug conjugate in adrenocortical carcinoma
Authors: Sun Nai-Yun , Kumar Suresh , Weiner Amber , Kim Yoo Sun , Mendoza Arnulfo , Nguyen Rosa , Okada Reona , Pommier Yves , Martinez Dan , Pogoriler Jennifer , Diskin Sharon , Maris John , Del Rivero Jaydira , Roper Nitin
Published: March 2024

Adrenocortical carcinoma (ACC) is an aggressive and rare endocrine malignancy with poor prognosis. First-line therapy (adrenolytic agent mitotane in combination with chemotherapy) for recurrent and metastatic ACC has limited efficacy and there are no approved second-line therapies. Antibody-drug conjugates (ADCs) are an emerging immunotherapeutic class in which a cytotoxic payload is directed to tumor cells via antibodies to cell surface proteins. As Notch ligands, such as DLL3, are ADC targets in neuroendocrine cancers, we screened for expression of Notch ligands in ACC. Among Notch ligands (DLL1, DLL3, DLK1, JAG1, JAG2), DLK1 (delta-like non-canonical Notch ligand 1) was the most highly expressed. Moreover, ACC had the near highest expression of DLK1 across all TCGA tumors likely because this ligand is of adrenal origin (with limited expression in other normal tissues apart from the pituitary gland and ovaries). By immunohistochemistry, we verified DLK1 to be expressed, at variable levels, in 97% of ACC tumors (n=30/31). We then tested a DLK1-directed antibody-drug conjugate (ADCT-701; DLK1-PBD), consisting of a humanized anti-DLK1 monoclonal antibody coupled to DNA damaging pyrrolobenzodiazepine (PBD) dimers (SG3199; drug-to-antibody ratio~1.8) via a cleavable linker in ACC pre-clinical models. ADCT-701 exhibited potent, nanomolar cytotoxicity in DLK1-expressing ACC cell lines and ACC patient-derived short-term organoid cultures. ADCT-701 cytotoxicity was dependent on DLK1 expression as DLK1 knockout and DLK1 overexpression abrogated and facilitated cytotoxicity, respectively. Mechanistically, ADCT-701 induced cytotoxicity through DLK1 dependent receptor-mediated internalization and DNA damage (γH2AX) as well as apoptosis (annexin V/PI positive cells, cleaved PARP, and cleaved caspase-3). In vivo studies showed that ADCT-701 was highly effective against DLK1-positive ACC xenografts and PDX models with durable anti-tumor activity. Our pre-clinical data demonstrate DLK1 as an important therapeutic target in ACC and support an upcoming phase I clinical trial of ADCT-701 in patients with neuroendocrine tumors including ACC (NCT06041516).

Citation Format: Nai-Yun Sun, Suresh Kumar, Amber Weiner, Yoo Sun Kim, Arnulfo Mendoza, Rosa Nguyen, Reona Okada, Yves Pommier, Dan Martinez, Jennifer Pogoriler, Sharon Diskin, John Maris, Jaydira Del Rivero, Nitin Roper. Targeting DLK1, a Notch ligand, with an antibody-drug conjugate in adrenocortical 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 6573.
Abstract 6590: Novel WRN helicase inhibitors selectively target microsatellite unstable cancer cells
Authors: Picco Gabriele , Rao Yanhua , Al Saedi Angham , Vieira Sara F. , Lee Yang , Shenje Ray , Bhosle Shriram , Walker Samantha , May Kieron , Herranz-Ors Carmen , Dicer Cansu , Gibson Freddy , Banerjee Ruby , Werner Thilo , Cottom Josh , Peng Yang , Deng Nanhua , Landis Phil , Angel Thomas , Bush Jacob , Rees Matthew G. , Ronan Melissa M. , Roth Jennifer A. , Lightfoot Howard , Zappacosta Francesca , Pettinger Jonathan , Barthorpe Syd , Eberl Chris , Jones Brian , Schneck Jess , Murphy Dennis , Taygerly Josh , DeMartino Mike , Coelho Matthew , Houseley Jon , Schwartz Benjamin , Garnett Mathew J.
Published: March 2024

Microsatellite-unstable (MSI) cancers depend on the WRN helicase to resolve replication stress from expanded (TA)-dinucleotide repeats. WRN is a promising synthetic lethal target for MSI tumours and WRN inhibitors are being developed. Here, we used CRISPR-Cas9 base editing to map WRN residues critical for MSI synthetic lethality, validating the helicase domain as the primary target and guiding inhibitor discovery. Fragment-based screening led to the discovery of potent and highly selective WRN helicase covalent inhibitors from the same chemical series. These compounds strikingly and selectively suppressed MSI model growth in vitro and in vivo by mimicking genetic WRN loss, inducing DNA double-strand breaks at expanded TA repeats and DNA damage response. We characterized WRN inhibition across cancer cell lines and patient-derived tumour organoids, enabling biomarker assessment of TA-repeat expansions and MMR status to refine patient selection, with compound efficacy correlating with TA-repeat expansions in MSI cells. Efficacy was also confirmed in patient-derived organoids and PDX models refractory to immunotherapy. The discovery of potent and selective covalent WRN inhibitors provides proof-of-concept for targeting MSI cancers and provides tools to unlock the molecular dissection of the WRN biology and MSI synthetic lethality.

Citation Format: Gabriele Picco, Yanhua Rao, Angham Al Saedi, Sara F. Vieira, Yang Lee, Ray Shenje, Shriram Bhosle, Samantha Walker, Kieron May, Carmen Herranz-Ors, Cansu Dicer, Freddy Gibson, Ruby Banerjee, Thilo Werner, Josh Cottom, Yang Peng, Nanhua Deng, Phil Landis, Thomas Angel, Jacob Bush, Matthew G. Rees, Melissa M. Ronan, Jennifer A. Roth, Howard Lightfoot, Francesca Zappacosta, Jonathan Pettinger, Syd Barthorpe, Chris Eberl, Brian Jones, Jess Schneck, Dennis Murphy, Josh Taygerly, Mike DeMartino, Matthew Coelho, Jon Houseley, Benjamin Schwartz, Mathew J. Garnett. Novel WRN helicase inhibitors selectively target microsatellite unstable cancer cells [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 6590.
Abstract 6609: NRF2/ACSS2 axis regulates alcohol-induced metabolic reprogramming in esophageal squamous epithelial cells
Authors: Xiong Zhaohui , Subramaniyan Boopathi , Paiboonrungruang Chorlada , Li Yahui , He Wentao , Yuan Hong , Zhang Guofang , Chen Xiaoxin
Published: March 2024

Esophageal diseases such as gastroesophageal reflux disease (GERD) and esophageal cancer have a strong association with alcohol drinking. However, the molecular mechanisms of alcohol-induced esophageal pathology remain unclear. In our previous study, we identified acyl-CoA synthetase short-chain family member 2 (ACSS2) as a transcriptional target of nuclear factor erythroid 2-related factor 2 (NRF2) in the esophageal epithelial cells in vitro and in vivo. Ethanol exposure enhanced de novo lipogenesis in NRF2high cells and generated a more energetic and invasive phenotype. In this study, we aimed to investigate the role of the NRF2/ACSS2 axis in regulating alcohol-induced metabolic reprogramming in esophageal squamous epithelial cells. We first demonstrated that ethanol exposure activated NRF2 signaling and upregulated the expression of NRF2 and ACSS2 in human esophageal squamous epithelial cells. 13C-ethanol/13C-acetate metabolic flux assay showed a dramatic NRF2-dependent increase of labeling of the TCA cycle intermediates and de novo lipogenesis in NRF2high cells in comparison with NRF2null or NRF2low cells. Long-term ethanol exposure caused metabolic reprogramming, in particular induced de novo lipogenesis, in the mouse esophagus according to metabolomics profiling of 833 metabolites. PET/CT and autoradiography showed increased 11C-acetate uptake in the NRF2high esophagus of a conditional tissue-specific mouse (Sox2CreER;LSL-Nrf2E79Q) due to upregulation of transporters and metabolic enzymes. In summary, Our data demonstrated the functional role of the NRF2-ACSS2 axis in alcohol-induced metabolic reprogramming in esophageal squamous epithelial cells both in vitro and in vivo, suggesting NRF2/ACSS2 inhibition as a novel mechanism-based prevention for alcohol-associated esophageal pathology.

Citation Format: Zhaohui Xiong, Boopathi Subramaniyan, Chorlada Paiboonrungruang, Yahui Li, Wentao He, Hong Yuan, Guofang Zhang, Xiaoxin Chen. NRF2/ACSS2 axis regulates alcohol-induced metabolic reprogramming in esophageal squamous epithelial cells [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 6609.
Abstract 664: GSC000190, a highly potent inhibitor of KIF18A, for tumors with chromosome instability
Authors: Tu Peng , Zhang Chen , Lu Biao , Xia Yuanfeng , Yang Fanglong
Published: March 2024

Chromosome instability (CIN) and Genetic instability is a common feature of malignant tumor cells, which may contribute to tumor progression and lead to drug resistance and tumor metastasis. KIF18A, a member of the kinesin-8 family, is an ATP dependent plus end microtubule motor protein. Studies have found that genetic depletion of KIF18A greatly impacts the chromosome alignment, elongation of mitotic spindles, activation spindle assembly checkpoint of CIN+ tumor cell and leads to cell death, while have little impact towards the survival of normal cells, making KIF18A an attractive therapeutic target for targeting the vulnerability of CIN related tumors. Here we report the pharmacology characterization of a “best in class” potential KIF18A inhibitor for CIN+ tumors. In vitro, GSC000190 inhibited KIF18A ATPase activity with a single nM potency and has great potency inhibiting growth of a wide range of TP53 mutant/CIN+ tumor cells. In vivo, GSC000190, at approximately one tenth of systematic exposure comparing to that of AMG650, the leading clinical KIF18A inhibitor, causes tumor shrinkage in multiple CDX models including ovarian, colon and lung cancers. In an HGSOC PDX model which is resistant to platinum and olaparib, GSC000190 induced strong tumor regression both as single agent and through combination without significant body weight reduction. PD study confirms a more elevated mitotic phosphorylated histone 3 (PH3) staining in GSC000190 treated tumor tissues, correlating with a better in vivo efficacy than that of AMG650. GSC000190 has a favorable ADME profile in rodents, dogs and NHPs, as well as a much better safety profile. GSC000190 is now under IND-enabling study and P1 study is planned in the second quarter of 2024.

Legal entity responsible for the study: The authors.

Disclosure: All authors have declared no conflicts of interest.

Citation Format: Peng Tu, Chen Zhang, Biao Lu, Yuanfeng Xia, Fanglong Yang. GSC000190, a highly potent inhibitor of KIF18A, for tumors with chromosome instability [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 664.
Abstract 6645: Temporal immune profiling reveals systemic anti tumor immunity in triple negative breast cancer(TNBC) patients treated with immunotherapy and radiation
Authors: Devarakonda Vaishnavi , Viramontes Jolene , Stevens Satchel , Dar Tahir , Ko Emily , Canesco Elvin , Anderson Kaiden , Guarnerio Jlenia , Knott Simon , Shiao Stephen L.
Published: March 2024

Combining pembrolizumab (anti-PD1) with radiation therapy (RT) has shown to enhance response rates in TNBC. We hypothesize that this improved efficacy is not just localized to the tumor bed, but also involves a broader systemic immune response, although the precise mechanisms are yet to be fully understood. Therefore, in this study, we aimed to investigate T cell clonal dynamics in Tumor and peripheral blood mononuclear cells (PBMCs) in 9 patients (6 responders(R) and 3 non-responders (NR)) from 3 different timepoints (before therapy (Baseline), after anti-PD1 alone and after anti-PD1+RT). CD45+ positive stained cells were sorted for subsequent single-cell RNA and T-cell receptor (TCR) sequencing analysis.Through single-cell analysis, we identified increased proportions of exhausted CD8+ and Treg cells from baseline to both treatment points, whereas exhaustedCD4+ T cells increased in proportions after PD1 alone in Responders. We aimed to then understand the origin of these cells, and how they might contribute to systemic immunity. Hence, by TCR overlap between Tumor and PBMC’s we detected 590 overlapped clones in CD8 and 1000 overlapped clones in CD4 T cells. Neo-TCR score was higher in these overlapped clones, suggesting tumor reactive clones can be identified in PBMC’s. Compared to exhausted CD4, exhausted CD8 T cell and Treg had higher overlapped clones between Tumor and PBMC. We also found that exhausted CD8+T cells clonal expansion after treatment was higher in pre-existing clones, compared to new clones in Responders. These pre-existing clones consisted of overlapped clones, suggesting tumor reactivity to be present in PBMC’s before treatment. Further investigation suggested that exhausted CD8+ cells also showed increased transition to TEMRA (in PBMC) and a tissue-resident memory CD8 T cell subset, under combination therapy. This pattern was not seen in exhausted CD4+Tcells or Treg cells, indicating that CD8+ T cell subsets in the blood are crucial in driving systemic anti-tumor immunity. Overall, this study has identified the systemic immune response triggered by the combination of anti-PD1 and radiation therapy highlighting its potential to inform and refine future therapeutic strategies in TNBC treatment.

Citation Format: Vaishnavi Devarakonda, Jolene Viramontes, Satchel Stevens, Tahir Dar, Emily Ko, Elvin Canesco, Kaiden Anderson, Jlenia Guarnerio, Simon Knott, Stephen L. Shiao. Temporal immune profiling reveals systemic anti tumor immunity in triple negative breast cancer(TNBC) patients treated with immunotherapy and radiation [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 6645.
Abstract 6655: Oncolytic adenovirus dually expressing interferon beta and membrane-stable CD40 ligand increases polyfunctional CD8+T cells associated with antitumor activity
Authors: Cantwell Mark J. , Saltos Andreas N. , Zheng Hong , Foresman Dana , Beg Amer A.
Published: March 2024

MEM-288 is a dual-transgene armed oncolytic adenovirus in phase 1 clinical development as a standalone agent and in combination with immune checkpoint inhibitors (ICI). It encodes two potent immune agonists: IFNβ and a recombinant membrane-stable chimeric form of CD40L (MEM40). We previously demonstrated this agonist combination is better than either agonist individually to activate conventional dendritic cells type 1 (cDC1) crucial for CD8+ T cell cross-priming, and to increase tumor-antigen reactive CD8+ T cells. Furthermore, first-in-human Phase 1 clinical trial (NCT05076760) results of MEM-288 for advanced non-small cell lung cancer (NSCLC) and other solid tumors showed MEM-288 tumor shrinkage was associated with systemic antitumor T cell immunity as demonstrated by cytokine, T cell clonotype, and tumor neoantigen analysis. Here, we investigated the precise nature of the localized and systemic T cell response induced by MEM40 + IFNβ in preclinical tumor models. Single-cell RNA sequencing of tumor infiltrating T lymphocytes (TILs) revealed that MEM40 + IFNβ elicited a strong increase in T cells expressing Granzyme B and PRF1, key effector cytokines and cytotoxicity mediators. We tracked the CD8+ T cell response in CD45.1 C57BL/6 mice implanted with syngeneic B16 tumor expressing the model antigen OVA. Interestingly, intratumoral treatment with adenovirus encoding MEM40 + IFNβ did not cause an appreciable increase in absolute numbers of antigen-reactive CD8+ T cells, despite tumor growth inhibition. However, MEM40 + IFNβ compared to control unarmed adenovirus induced a significant (p < 0.005) 5-fold increase in polyfunctional IFNγ+TNFα+PRF1+ and IFNγ+TNFα+Granzyme B+ CD8+ T cells. Polyfunctional CD8+ T cells have the capacity to simultaneously produce effector cytokines and cytotoxicity mediators and are known to be strongly associated with antitumor T cell activity. The robust polyfunctional CD8+ T cell response in these studies is consistent with T cell-driven antitumor activity found in both our preclinical tumor experiments and our clinical studies in advanced NSCLC patients responding to MEM-288. Overall, our findings suggest MEM40 + IFNβ generates a strong polyfunctional CD8+ T cell response in the TME that warrants continued evaluation to understand the pleiotropic mechanisms of this cancer immunotherapy.

Citation Format: Mark J. Cantwell, Andreas N. Saltos, Hong Zheng, Dana Foresman, Amer A. Beg. Oncolytic adenovirus dually expressing interferon beta and membrane-stable CD40 ligand increases polyfunctional CD8+T cells associated with antitumor activity [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 6655.
Abstract 6666: Leveraging an obligate anaerobic salmonella strain for targeted cargo delivery in the tumor microenvironment to restore immunotherapy sensitivity
Authors: He Yige , Huang Jiandong
Published: March 2024

Tumor immunotherapy is often hindered by unresponsive cold tumor microenvironments (TME). Although Salmonella-based immunotherapy has shown potential in overcoming these cold immune environments, safety concerns remain. Our study introduces a genetically reprogrammed Salmonella typhimurium strain (OASL) with a dual safety lock to enhance safety and modify immunosuppressive TME, sensitizing tumors to immunotherapies. We propose using OASL to alter the cold TME and locally release therapeutic cargos such as PDL1 nanobodies and tumor-specific neoantigen peptides identified through bioinformatic algorithms, activating immune cells within the tumor while minimizing side effects. We selected YB1, an obligate anaerobic Salmonella strain that thrives in hypoxic environments, as our base strain and incorporated a self-lysis genetic circuit for controlled bacterial growth and cargo release upon reaching a specific population density within the tumor core. We assembled and evaluated the self-lysis gene circuit in vitro, documenting the event using an optical density (OD) reader and confirming OASL's ability to express genetic cargos through western blot analysis. We then investigated OASL's therapeutic effect in vivo and characterized TME changes using flow cytometry and immunohistochemistry staining. Our results indicate that OASL undergoes lysis and releases cargos upon reaching a specific population density in vitro. Additionally, OASL-delivered neoantigen peptides elicited a tumor-specific immune response in vivo. OASL also demonstrated the capacity to modify the TME and restore sensitivity to PDL1 in previously unresponsive tumors, enhancing therapeutic effects.

Citation Format: Yige He, Jiandong Huang. Leveraging an obligate anaerobic salmonella strain for targeted cargo delivery in the tumor microenvironment to restore immunotherapy sensitivity [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 6666.
Abstract 670: Preclinical candidate LAE120, a novel selective USP1 inhibitor shows effective anticancer and combination activity with PARP inhibitor
Authors: Wang Jintao , Chen Yan , Chen Junyan , Jiang Ling , Lin Xiaofen , Cai Chaojun , Zhang Minhua , Li Ming , Gu Justin
Published: March 2024

The Fanconi anemia (FA) and translesion synthesis (TLS) are DNA damage tolerance and repair pathways that have been found to be regulated by reversible ubiquitination in which ubiquitin-specific protease 1 (USP1) plays a key role. Numerous studies have indicated that USP1 inhibitors have therapeutic effects on tumors with homologous recombination deficiency (HRD), including mutations in BRCA1/2. Due to the emergence of resistance to PARP inhibitors in clinical applications, new strategies are needed to address this issue. Here we present LAE120, a novel, allosteric and highly potent USP1 inhibitor, displayed monotherapy potency and combination activity with PARP inhibitor in HRD cancers. LAE120 has a unique tail group distinct from all the published USP1 inhibitors and is predicted to induce a different conformational change at the USP1 allosteric site. In the biochemical assay, LAE120 strongly inhibited USP1 enzymatic activity with IC50 of 5.6 nM. LAE120 potently inhibited proliferation of BRCA-mutated MDA-MB-436 breast cancer cell (IC50:19 nM) and exhibited anti-proliferative activity in NCI-H1792 (IC50: 69 nM) and K562 (IC50: 38 nM) cell lines. In the xenograft model of MDA-MB-436 cells with BRCA mutations, LAE120 demonstrated robust single-agent tumor inhibitory activity (TGI: 88%, 10 mg/kg BID) and a favorable dose-dependent response (TGI: 106%, 25 mg/kg BID). We also observed strong tumor-inhibition efficacy of LAE120 as a single agent in the K562 xenograft model with Bcr-Abl expression (TGI: 86%, 10 mg/kg BID). Current research indicates that USP1 inhibitors exhibit synergistic activity in combination with PARP inhibitors and re-sensitizes PARP refractory tumors. Similar results have been confirmed in the xenograft model of BRCA-mutated MDA-MB-436 cells. The combination of LAE120 and Olaparib (PARP inhibitor) yielded a more robust and durable anti-tumor efficacy at low dose (TGI: 110%, LAE120, 5 mg/kg BID + Olaparib, 50 mg/kg QD). LAE120 also displayed favorable ADME properties and PK profiles. Preclinical-tox studies indicated the molecule was well tolerated without significant toxicities and hematological observations. Both in vitro and in vivo data strongly support further investigation of LAE120, whether as a single agent or in combination therapy.

Citation Format: Jintao Wang, Yan Chen, Junyan Chen, Ling Jiang, Xiaofen Lin, Chaojun Cai, Minhua Zhang, Ming Li, Justin Gu. Preclinical candidate LAE120, a novel selective USP1 inhibitor shows effective anticancer and combination activity with PARP inhibitor [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 670.
Abstract 6727: QL335, a novel T cell engager with enhanced safety profile targeting MSS colorectal cancer
Authors: Gu Shenda , Guo Guangjie , Yee Helena , Tran Hieu V. , Chen Shihao , Cao Chuanzeng , Liu Ke , Jin Chunyan , Lun Weihua , Ma Ruixue , Ren Lele
Published: March 2024

Colorectal cancer (CRC) is the fourth leading cause of death in the world with a global mortality rate of over 700,000 annually. While recent advancement in diagnosis and prevention has reduced the overall number of deaths, the lack of effective and durable treatment has not significantly improved survival rate. Emerging modalities in immunotherapy such as T cell engagers have paved new ways for disease management. However, a common challenge to advancing T cell engagers in the clinic is poor target specificity and high toxicity associated with non-specific T cell activation and cytokine release. To overcome these shortcomings, we have developed QL335, a bispecific antibody bridging LY6G6D antigen on tumor cells and CD3 on T cells. LY6G6D or Lymphocyte Antigen 6 Family Member G6D, is a GPI-anchored membrane protein that, according to TCGA RNAseq data, is highly expressed in microsatellite stable (MSS) colorectal cancer but not in normal tissues. We analyzed LY6G6D expression by IHC in over 200 CRC patient tumors and 40+ normal tissue samples from different organs, confirming its highly restricted CRC expression pattern. We constructed our bispecific antibody in a 2+1 format, comprising two high affinity LY6G6D binding domains and one reduced affinity CD3 binding domain. Such format allows for higher tumor accumulation while mitigating non-specific T cell activation in the periphery. In vitro evaluation showed that QL335 induced potent yet highly specific T cell activation and killing of only target cells expressing LY6G6D. QL335 demonstrated robust anti-tumor efficacy in vivo against human colon cancer xenograft models with human PBMC reconstitution. Importantly, QL335 was well tolerated in cynomolgus monkeys dosed up to 50 mg/kg, supporting the enhanced safety profile by design of this therapeutic candidate. QL335 is currently being evaluated in a phase 1 clinical trial.

Citation Format: Shenda Gu, Guangjie Guo, Helena Yee, Hieu V. Tran, Shihao Chen, Chuanzeng Cao, Ke Liu, Chunyan Jin, Weihua Lun, Ruixue Ma, Lele Ren. QL335, a novel T cell engager with enhanced safety profile targeting MSS 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 6727.
Abstract 6740: Next-generation LNPs induce effective anti-tumor T cell responses
Authors: Millar Douglas G. , Gold Matthew J. , Olsen Kirsten , Wu Yu , Karpov Yury , Nechanitzky Robert , Menon Haritha , Krishnan Rajesh , Georgantas Robert , Ohashi Pamela , Martin-Orozco Natalia
Published: March 2024

mRNA immunotherapies have gained interest for the treatment of tumors from various origins, however, their ability to provide long -term durable tumor control has been underwhelming. Here we report that novel mRNA lipid nanoparticle (LNP) vaccinations induce robust expansion of antigen-specific T cells, although this does not always correlate with their ability to infiltrate and kill solid tumors. Using a portfolio of novel ionizable lipids and a robust in vivo model that reliably identifies LNPs with prominent anti-tissue T cell activity we have identified a putative LNP candidate that provides long term tumor control in a murine syngeneic tumor model.

We utilized the model antigen glycoprotein (Gp), from the lymphocytic choriomeningitis virus (LCMV), and produced mRNA encoding the immunodominant epitopes gp3333-41, gp6161-80 and gp276276-286 (3GP-mRNA). This mRNA was encapsulated in various novel LNP formulations and administered i.m. into naïve C57Bl/6 mice to track the induction of a robust CD8+ T cell response identified using tetramers to gp33 and gp276. Successful candidate LNPs were then tested in the RIPgp model of autoimmune diabetes. RIPgp transgenic mice express LCMV-Gp in the pancreatic β cells and offer a robust assay for the ability to induce antigen-specific T cells capable of breaking self-tolerance and infiltrating and killing target tissue. Utilizing the RIPgp model to screen LNP candidates we identified a lead candidate, C2-5A, that both induced a robust expansion of antigen-specific T cells and tissue destruction. When utilized in a colon adenocarcinoma model expressing the LCMV-Gp antigen (MC38-Gp), therapeutic dosing of LNP C2-5A as a monotherapy lead to long term tumor clearance in 40% of the treated animals. We believe this screening platform allows the selection of LNP candidates capable of breaking self-tolerance, and one such candidate C2-5A provides a potent vehicle and adjuvant for mRNA based cancer vaccines.

Citation Format: Douglas G. Millar, Matthew J. Gold, Kirsten Olsen, Yu Wu, Yury Karpov, Robert Nechanitzky, Haritha Menon, Rajesh Krishnan, Robert Georgantas, Pamela Ohashi, Natalia Martin-Orozco. Next-generation LNPs induce effective anti-tumor T cell responses [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 6740.
Abstract 6758: Eradication of tumors and development of immunity from pHLIP-targeted intracellular delivery of STINGa
Authors: DuPont Michael , Moshnikova Anna , Iraca Marissa , Klumpp Craig , Visca Hannah , Allababidi Dana , Pelzer Phoebe , Engelman Donald , Andreev Oleg , Reshetnyak Yana
Published: March 2024

Activation of the stimulator of interferon genes (STING) pathway causes the release of factors that trigger the immune response in the tumor microenvironment (TME). Transient strong activation leads to immune activation and tumor suppression, while prolonged weak activation leads to immuno-suppression promoting tumor development. Reprogramming of M2-type tumor-associated macrophages (M2-TAMs) toward an M1 phenotype, suppression of cancer-associated fibroblasts (CAFs) and myeloid-derived suppressor cells (mMDSCs), as well as activation of dendritic cells (DCs) to train T-cells are advantageous, while the activation of STING pathway in T-cells is leads to their apoptosis. Thus, targeted delivery of STINGa to specific cells with TME to induce strong transient activation may be a key to therapy. We have developed a delivery approach that uses one or two pH Low Insertion Peptides (pHLIPs) that collaborate in the targeted intracellular delivery of a STINGa. STINGa were conjugated with pHLIPs via S-S cleavable self-immolating linkers. Biophysical studies were performed to ensure proper interactions of pHLIP-STINGa agents with membrane lipid bilayers. pHLIPs extend the lifetime of STINGa in the blood and target them to acidic cancer and stromal cells (CAFs), as well as M2-TAMs, mMDSCs and DCs within TME. The targeting results in selective cytokine activation in tumors with no systemic activation, which triggers the eradication of small (100 mm3) and large (400-700 mm3) CT26 tumors in mice after one or two doses of pHLIP-STINGa. The tumor stroma was destroyed, intratumoral hemorrhage developed, and the level of acidity within the TME was reduced. No tumors developed in mice re-challenged by an additional injection of cancer cells in a 90-day experiment. Thus, targeted delivery of STINGa to cancer cells, tumor stroma and TAMs induces activation of signaling, potentially resulting in the recruitment and infiltration of T- and NK-cells, which gain access to the tumor core. The cytotoxic activity of T- and NK-cells is not impaired by the acidic environment and immune memory is developed. The pHLIP technology may allow transformation of immuno-activating agents into more potent therapeutics, since pHLIP can target and deliver these agents to cancer cells, tumor stroma and myeloid cells.

Citation Format: Michael DuPont, Anna Moshnikova, Marissa Iraca, Craig Klumpp, Hannah Visca, Dana Allababidi, Phoebe Pelzer, Donald Engelman, Oleg Andreev, Yana Reshetnyak. Eradication of tumors and development of immunity from pHLIP-targeted intracellular delivery of STINGa [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 6758.
Abstract 6778: New microplate platform with cryopreserved 3D tumor spheroids for faster and convenient pre-clinical testing
Authors: Goedecke Nils , Stroebel Simon , Hutter Simon , Issa Tala , Agarkova Irina , Ligeon Laure-Anne , Frey Olivier
Published: March 2024

Drug discovery and safety testing depend on predictive in vitro models, including multicellular tissues with organotypic functions. While traditional 2D tumor cell cultures have been extensively used in early drug screening due to their user-friendly nature, automation compatibility, and high throughput, they fall short in representing the intricate 3-dimensional structure, physiology, and complex multicellular nature of actual tumors. However, generating such 3D tissues for each test campaign is labor intensive. In addition, not all researchers have the resources to establish these 3D models. To pave the way, we developed a new platform that offers a range of cryopreserved 3D tumor models in micro plate format allowing for high-content screening. It enables users to start testing compounds within a 3-to-5 days simply by thawing an ARCTis™ plate (Always Ready Cryo Tissues) and following clear instructions. Another advantage of these cryopreserved 3D models derives from the fact that they are made in larger batches which means the start point for compound testing is always the same. This improves data quality, maximizes the test window length, and makes the data comparable across work groups. Currently, our growing portfolio consists of 25 tumor cell lines from ATCC representing the most common solid tumors. Their functionality has been determined based on efficacy tests for each cell line with the apoptotic agent Staurosporine. Various cell lines exhibited compact spheroids with a round morphology, less compact aggregates with non-spherical morphology, or loose cell-cell interaction aggregates, which can correlate with their tumor site of origin. Upon treatment with Staurosporine the dose-response profiles indicated growth inhibition, tumor shrinkage, or tumor cell killing effects based on size assessment and cell metabolic analysis (ATP). Moreover, we demonstrated the robust performance of these assays from plates stored for up to 6 months at -80°C.In conclusion, this groundbreaking approach addresses the limitations of traditional 2D cell cultures by providing a high-throughput, in-plate frozen, 3D cell culture platform. By offering a combination of a more physiologically relevant representation of tumors with a robust frozen-storage and time flexible assay platform our method holds great promise for advancing cancer drug discovery by easing the exploration of complex drug testing screens in vitro.

Citation Format: Nils Goedecke, Simon Stroebel, Simon Hutter, Tala Issa, Irina Agarkova, Laure-Anne Ligeon, Olivier Frey. New microplate platform with cryopreserved 3D tumor spheroids for faster and convenient pre-clinical testing [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 6778.
Abstract 6800: The tumor progression mechanism of increasing CXCL16-CXCR6 pathway within the tumor microenvironment in TNBC
Authors: Lee Yun sun , Lee Cham Han , Ha Seong Yun , Lee Sang Hyeob , Yang Jin Yi , Kim Young Sang , Kim Sung Moo , Kim Seong Keun
Published: March 2024

Background: Triple negative breast cancer (TNBC) is characterized rapid progression, higher relapse, and poor prognosis, so the establishment of an effective therapeutic target is required. CXCL16, a chemokine abundantly present in the TNBC tumor microenvironment (TME), is secreted by tumor-associated macrophages (TAM) and is known to promote tumor growth and metastasis. However, the exact mechanism through which CXCL16 facilitates tumor growth and metastasis remains unclear. This study aims to study the role of CXCL16 in the tumor progression and confirm the anti-tumor effects of CXCL16 neutralization in TNBC model.

Method: MDA-MB-231 human TNBC cell lines were utilized for in vitro validation, and a syngeneic model involving 4T1 mouse TNBC cell lines and Balb/c mice was used for in vivo studies.

Results: Stimulation of TNBC cells with recombinant human CXCL16 protein (rhCXCL16) activates the tumor growth signaling pathways, including pAKT and STAT3, as well as EMT markers. These results shows that CXCL16 can promote tumor growth and metastasis. Treatment with CXCL16 neutralizing antibodies inhibited the promotion of cancer growth and metastasis by rhCXCL16. Additionally, combination treatment of CXCL16 antibodies with PD-1 antibodies in the 4T1 syngeneic model increased the proportion of CD8+ T cells and CD80+ M1 like macrophages. These results shows that neutralization of CXCL16 can regulate polarization of macrophage and proportion of T cells. These regulation and changes of immune cells allow neutralization of CXCL16 control the TME to resist tumor cells, suggesting that optimal condition can be constructed to maximize the effectiveness of anti-cancer drugs.

Conclusion: This study confirms that the CXCL16-CXCR6 pathway within the TME triggers tumor growth and metastasis, while neutralization of CXCL16 can inhibit tumor progression. This effect is attributed to the increase in CD8+ T cell and M1 macrophage proportions within the TME. In conclusion, these research findings propose the potential of CXCL16 as a novel biomarker and therapeutic target for TNBC.

Citation Format: Yun sun Lee, Cham Han Lee, Seong Yun Ha, Sang Hyeob Lee, Jin Yi Yang, Young Sang Kim, Sung Moo Kim, Seong Keun Kim. The tumor progression mechanism of increasing CXCL16-CXCR6 pathway within the tumor microenvironment in TNBC [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 6800.
Abstract 6879: Development of a rapid multiplex immunohistochemistry for characterizing tumor-immune microenvironment
Authors: Kimura Alisa , Tsujikawa Takahiro , Morimoto Hiroki , Mitsuda Junichi , Saburi Sumiyo , Mukudai Shigeyuki , Nagao Hikaru , Sakurai Nana , Murakami Nanako , Miyagawa-Hayashino Aya , Ogi Hiroshi , Shibata Saya , Konishi Eiichi , Itoh Kyoko , Hirano Shigeru
Published: March 2024

Intratumoral immune profiles have been related to prognosis and therapeutic efficacy; this could result in personalized treatment based on biomarkers. Although techniques for multifactorial evaluation of different tumor-immune microenvironments have been established, their practical implementation in clinical settings still requires further improvement, where the time required for testing needs to be reduced and the technology needs to be clinically validated. To develop a multiplex, quantitative, and rapid tissue evaluation method based on clinically established standard immunohistochemistry (IHC), we attempted to develop 6-marker rapid multiplex IHC based on our previously reported 14-marker multiplex IHC via the reduction of the number of labels and speeding up the staining procedure (Tsujikawa et al. Cell Reports, 2017). First, we confirmed whether immunological features that were found to be associated with prognosis in 14-marker multiplex IHC analyses could be identified with fewer labels. Quantitative results by selected six markers exhibited significant correlation with those by 14 markers in terms of immune classifications based on the balance of lymphoid and myeloid cells. Next, we developed a rapid staining protocol by optimizing the reaction temperature, chromogen, and washing time, allowing the completion of 6-marker analysis in 5 hours and 49 minutes as opposed to several days required for the conventional multiplex IHC. By using six markers, validation in benign tonsil tissue and head and neck cancer tissue exhibited significant correlation between rapid and standard multiplex IHC in terms of staining intensities, densities of T cells, macrophages, lymphoid/myeloid immune cells ratios, and spatial profiles of intratumoral immune infiltrates. This method may enable a quantitative assessment of tumor-immune microenvironment on a clinically feasible time scale, which promote the development of tissue biomarker-guided therapeutic strategies.

Citation Format: Alisa Kimura, Takahiro Tsujikawa, Hiroki Morimoto, Junichi Mitsuda, Sumiyo Saburi, Shigeyuki Mukudai, Hikaru Nagao, Nana Sakurai, Nanako Murakami, Aya Miyagawa-Hayashino, Hiroshi Ogi, Saya Shibata, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Development of a rapid multiplex immunohistochemistry for characterizing tumor-immune microenvironment [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 6879.
Abstract 6885: Investigating a novel role of DCLK1 isoforms in colitis and colitis associated colon cancer
Authors: Yusuf Kafayat Aderonke , Roy Badal C. , Anant Shrikant , Umar Shahid
Published: March 2024

Chronic intestinal inflammation in patients diagnosed with inflammatory bowel disease (IBD) significantly increases their risk of colorectal cancer (CRC). Despite the rising global frequency of IBD, the precise mechanisms that regulate the transition from IBD to colon cancer are poorly understood. Doublecortin-like kinase 1 (DCLK1) is a protein with two major isoforms, DCLK1-L and DCLK1-S. Previous studies have shown that hypermethylation of the DCLK-1α promoter encoding DCLK1-L, particularly in colorectal cancer, allows switching to the DCLK1-S isoform that confers an invasive tumor phenotype. The DCLK1-L is a tuft cell marker that protects against colitis by sensing and eliminating gut pathogenic infection through various mechanisms. On the contrary, the role of DCLK1-S in colitis and colitis-associated cancer has not been thoroughly investigated. Studies from our lab have identified a marked elevation of DCLK1-S in tissue samples of IBD patients. We also recently discovered that DCLK1-S is predominantly expressed in Ly6G+; MHCII- neutrophils, which coincide with elevated levels of inflammation and tissue damage in the colon. To further understand the role of DCLK1 isoforms in driving the progression of colitis to colon cancer, we bred Dclk1fl/fl mice with MRP8-Cre-ires/GFP mice to generate Dclk1fl/fl;MRP8-Cre+/- that eliminates DCLK1-L upon tamoxifen injection resulting in sustained expression of DCLK1-S in the granulocytes especially neutrophils. When infected with Citrobacter rodentium (CR), MRP8;Dclk1−/− mice compared to MRP8;Dclk1+/− or WT mice developed more severe colitis. We have also discovered a novel interaction between DCLK1-S and MMP13 in an unbiased docking study that correlated with significant co-localization of DCLK1-S with MMP13 in the colons of CR-infected mice. Employing a knock-in mice over-expressing the DCLK1-S +19 under the CAG promoter, the DCLK1-MMP13 co-localization correlated with severe ulceration and colitis with loss of crypts and immune cell infiltration including Ly6G+ neutrophils. Studies are underway to see if the severity of colitis in MRP8;Dclk1−/− mice translates into enhanced tumorigenesis and to see if potential interaction between DCLK1-S and MMP13 could provide a plausible mechanism of colitis progression to colon cancer through ECM remodeling and tissue damage.

Citation Format: Kafayat Aderonke Yusuf, Badal C. Roy, Shrikant Anant, Shahid Umar. Investigating a novel role of DCLK1 isoforms in colitis and colitis associated colon 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 6885.
Abstract 6905: A multi-targeted approach to evaluate therapeutic selection and efficacy in preclinical GBM models
Authors: Eastwood Emily , Carapia Bianca , Rodriguez Javier , Buck Kristen , Gorospe Derrick , Valencia Elizabeth , Corcoran Bridget , Pippa Raffaella , Chien Yuan-Hung , Andrews Warren , Do Long , Nakashima Jonathan K. , Sperry Jantzen
Published: March 2024

Glioblastoma (GBM) is a devastating primary brain cancer with approximately 10,000 new US diagnoses annually. The current standard of care (SOC) for GBM includes surgical resection followed by radiation therapy (RT) and temozolomide (TMZ), however, there is near universal recurrence and development of resistance after treatment. Relapse in disease is tightly linked with dynamic changes in gene expression during tumor evolution, highlighting the need for stronger preclinical GBM models. Here, we report developing a pair of patient-derived xenograft (PDX) models from surgical resections obtained from initial GBM incidence in a patient (BarneyOI™ Cancer Model CRT00433) and subsequent recurrence following treatment (BarneyOI Cancer Model CRT00435) to study disease progression and novel treatment strategies. Recent studies have suggested the utilization of combination therapy approaches for GBM patients to address TMZ resistance. To this end, Certis has developed a personalized, AI-based approach to predict and test combination therapies in preclinical cancer models. Accuracy of the predicted sensitivities to treatment was evaluated in vivo using both subcutaneous (SC) and orthotopic (OT) mouse models. Luciferase-tagged CRT00433 and CRT00435 spheroid cell lines were transduced with firefly luciferase and implanted intracranially by stereotactic surgery for OT monitoring. Optical bioluminescence imaging (BLI) and murine-scale MRI from Aspect Imaging were used to assess therapeutic response of AI-predicted combination therapies and SOC treatment.

Citation Format: Emily Eastwood, Bianca Carapia, Javier Rodriguez, Kristen Buck, Derrick Gorospe, Elizabeth Valencia, Bridget Corcoran, Raffaella Pippa, Yuan-Hung Chien, Warren Andrews, Long Do, Jonathan K. Nakashima, Jantzen Sperry. A multi-targeted approach to evaluate therapeutic selection and efficacy in preclinical GBM models [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 6905.