bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 640: In vivo rescue of p53 tumor suppressor function with ADGN-531 across Pan-p53 alterations
Authors: Divita Gilles , Grunenberger Audrey , Czuba Elodie , Josserand Veronique , Guidetti Melanie , Desai Neil
Published: March 2024

p53 tumor suppressor mutations result in loss of function of p53 in approximately 50% of all human cancers.TP53 missense, nonsense mutations and p53 deletion are present in about 50%, 12% and 5% of all p53 driven cancers, respectively. To date there is no effective treatment for rescuing p53 function in cancers using a pan-p53 approach. The use of ADGN-531 is a new potent strategy combining mRNA with a tumor selective peptide nanocarrier to rescue of p53 tumor suppressor function.

ADGN-531 contains proprietary p53-mRNA complexed with proprietary short amphipathic peptides in the form of nanoparticles. ADGN-531 was evaluated on 20 different cancer cell lines harboring various p53 mutations. In-vivo efficacy of IV-administered ADGN-531 nanoparticles was evaluated on colorectal SW403 (p53 nonsense/KRASG12V), osteosarcoma SaOs2 (p53 null) and NSCLC NCI-H358 (p53 null/KRASG12C) mouse xenografts at a dose of 0.25-1.0 mg/kg weekly. ADGN-531/sotorasib synergy was evaluated in vitro on NCI-H358 (p53 null/KRASG12C) and Mia-PACA (p53R48W/KRASG12C) cells and in vivo on NCI-H358 mouse xenograft. ADGN-531 markedly inhibits the growth of a large panel of cancer cells harboring p53-missense or nonsense mutations or p53-deletion, by rescuing p53 transcriptional activity and subsequent expression of its target proteins.

ADGN-531 induces cell cycle arrest in G1 due to p21 upregulation and apoptosis following BAX and PUMA activation. IV-administration of ADGN-531 resulted in dose responsive tumor growth inhibition in SaOs2, SW403 and H358 xenografts independent of KRAS status. We demonstrated a strong synergy in a NSCLC H358 xenograft (tumor regression 80%) when restoring P53 function with ADGN-531 (0.5mg/kg, weekly) along with inhibition of KRASG12C mutant using sotorasib (10mg/kg, daily). ADGN-531 potentiated the effect of sotorasib on sotorasib resistant cells harboring high level of KRASG12C in permanent active state. ADGN-531 treatments are well tolerated, no sign of clinical toxicity was detected after single or repeated administrations.

ADGN-531 is effective in rescuing p53 function both in vitro and in vivo across a wide range of p53 alterations. Our study provides a proof-of-concept that restoration of tumor suppressor function by ADGN-531 could be used as a single agent therapy in P53 altered tumors independent of other driver mutations e.g., KRAS, or with other therapies for potent combinatorial cancer treatment.

Citation Format: Gilles Divita, Audrey Grunenberger, Elodie Czuba, Veronique Josserand, Melanie Guidetti, Neil Desai. In vivo rescue of p53 tumor suppressor function with ADGN-531 across Pan-p53 alterations [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 640.
Abstract 6417: Urinary PKM2 in muscle invasive bladder cancer
Authors: Matye David , Leak Juliann , Abbott Erika , Woolbright Benjamin , Taylor John
Published: March 2024

Background & Aims: Biomarkers are commonly used for both detection of cancer and monitoring response to treatment. Although several biomarkers have demonstrated promise in patients with bladder cancer (BCa), only urine cytology is widely utilized. Increased availability of effective biomarkers may improve clinical decision making and reduce the need for more invasive imaging. The M2 isoform of pyruvate kinase (PKM2) is upregulated in a number of cancers, including BCa, and promotes metabolic changes, including a shift to aerobic glycolysis. The aim of this study was to determine whether urine PKM2 levels are useful for detection and monitoring response to cisplatin-based neoadjuvant chemotherapy in patients with muscle invasive BCa.

Methods: Urine samples from patients enrolled in the University of Kanas Medical Center Bladder Cancer Biorepository were analyzed for levels of PKM2. Patients were included if they had both T2 stage disease and had received cisplatin-based neoadjuvant chemotherapy and were compared to healthy controls. Patients were categorized based on their pathological response to treatment and recurrence of disease within two years of definitive surgery. Urinary PKM2 levels were measured and evaluated for their ability to predict response to treatment and two-year disease-free survival.

Results: Immunohistochemistry revealed high levels of PKM2 within muscle invasive tumors compared to adjacent tissue. Patients with BCa had 150-fold increase in levels of urinary PKM2 compared to controls. However, there were no differences in urine PKM2 levels in patients with complete pathological response compared to those with no response. Urine PKM2 showed limited predictive value for disease recurrence (area under receiver operating characteristic curve = 0.65).

Conclusion: Urine levels of PKM2 are significantly elevated in patients with muscle invasive BCa and may be useful for tumor detection. Urinary PKM2 is less effective at monitoring response to treatment and may instead represent a marker of urothelial susceptibility to tumor formation.

Citation Format: David Matye, Juliann Leak, Erika Abbott, Benjamin Woolbright, John Taylor. Urinary PKM2 in muscle invasive bladder 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 6417.
Abstract 6461: Prevalence and implications of potentially pathogenic germline variants among adult patients in the Philippines with solid malignancies who underwent tumor genomic profiling: A multi-institutional, cross-sectional study
Authors: Franco Paula Isabel Gimena , Que Frances Victoria , Andal Jose Jasper , Ang Daphne
Published: March 2024

Background: In high income countries, 2-10% of tumor genomic profiling reports reveal incidental pathogenic germline variants. A third of these patients would not qualify for genetic testing based on current guidelines. In South East Asia, despite increased use of outsourced genomic profiling platforms, there are no published studies exploring the prevalence of these potentially pathogenic germline variants (PPGV). Our study determined the prevalence of PPGVs among adult patients with solid malignancies who underwent liquid or tissue-based tumor genomic profiling in the Philippines.

Methods: Annotated reports of patients with solid cancers who underwent tumor genomic profiling using FoundationOne or FoundationOne Hemebetween January 2021 to July 2023 were reviewed (Ethical Board ID: SL-23143). PPGVs were identified according to recommendations from American Board of Medical Genetics and Genomics and expert review. PPGV criteria include having a variant allele frequency of >30% and were categorized as: 1) high penetrance gene (HP), founder variant (FV), or variant associated with clinical presentation (VA). Cross-checking the pathogenicity through ClinVar database was also done.

Results: Out of 446 patients, 13 PPGV variants were found in 50 (11.2%) patients at a median age of 60.5 years. Of these, 28 (54%) had high penetrance (BRCA1, BRCA2, MSH2, MSH6, MLH1, RAD51C, RAD51D), 24 (46%) patients had VA (APC, SMAD4, CDH1, CDKN2A,PTEN) and two patients with lung cancer had a founder variant (EGFR p.Thr790Met). PPGVs were primarily found in colorectal (42% of 50 patients with PPGVs), breast (16%), ovarian (6%) and lung (6%) cancer patients (p<0.001). HP genes were mostly found in females (71.4%, p = 0.03), driven by BRCA1/2 variants (15 females and 2 males).

Conclusions: The presence of PPGVs warrants formal genetic counselling and germline testing. Given the similar prevalence of PPGVs in this study compared with data from other countries, and the diagnostic and therapeutic implications of detecting incidental PPGVs, we underscore the need for cancer genetics to be incorporated into standard oncologic care in the Philippines.

Citation Format: Paula Isabel Gimena Franco, Frances Victoria Que, Jose Jasper Andal, Daphne Ang. Prevalence and implications of potentially pathogenic germline variants among adult patients in the Philippines with solid malignancies who underwent tumor genomic profiling: A multi-institutional, cross-sectional study [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 6461.
Abstract 6473: Evaluation of bladder cancer patients' utilization of urologic telehealth services
Authors: Goldenthal Steven , Posid Tasha , Heh Victor , Denis-Diaz Dairon , Asif Hafsa , Arnold Chase , Gold Henry , Kim Tae-Hee , Ndumele Amara , Amin Sabrina , Lierz Matthew , Xu Vivian , Cronin Tyler , Khuhro Aliza , Lee Cheryl
Published: March 2024

Introduction: Infection control practices and public policy in response to the COVID-19 pandemic shifted healthcare practices towards a telemedicine format. Even two years after peak onset of the pandemic, many clinics, including our own institution, maintain a working telehealth option for patient visits. Our objective was to evaluate patient utilization of telehealth visits versus in-person visits at our institution and whether this was impacted by clinical stage, rural/urban status, distance from a large urban academic center, payor status, or comorbidities.

Methods: Medical Record Numbers for all patients with bladder cancer were pulled via the Qlik platform from the period 7/1/2019-2/28/2022. Chart review was conducted to pull clinical data on patients including telehealth versus in person visits, demographic data, clinical stage, comorbidities (diabetes, smoking status, BMI), rural/urban status by zip code (>50,000, <50,000 individuals) and income levels by zip code (25K-49.9K, 50K-99.9K, <100K), payor status (Medicare, Managed care, Medicaid, other government, ODRC, or self-pay), patient distance, and gas savings/carbon footprint.

Results: 430 patients completed in person visits while 268 completed telehealth visits. There was no statistically significant difference for in person visits vs. telehealth visits regarding patients’ race (p=0.541), ethnicity (p=0.394) age (p=0.862), urban/rural status (p=0.507), payor status (p=0.127), mean zip code income (p=0.175), and comorbidities (p=0.626 for diabetes, p = 0.706 for smoking, p = 0.459 for BMI), and clinical stage (p=0.07). There was a statistically significant difference in mean distance (14.85 miles versus 26.86 miles, p<0.01).

Conclusion: Patients’ with bladder cancer receive care from their urologist via in person visits versus telehealth at similar rates irrespective of their urban/rural status, demographics, payor status, relevant comorbidities, or relative income. Patients are more likely to engage in care with their urologist via telehealth if they live farther from a large urban academic center, which produces an economical and environmental impact via gas/time savings and reduced carbon footprint.

Citation Format: Steven Goldenthal, Tasha Posid, Victor Heh, Dairon Denis-Diaz, Hafsa Asif, Chase Arnold, Henry Gold, Tae-Hee Kim, Amara Ndumele, Sabrina Amin, Matthew Lierz, Vivian Xu, Tyler Cronin, Aliza Khuhro, Cheryl Lee. Evaluation of bladder cancer patients' utilization of urologic telehealth services [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 6473.
Abstract 65: Differential impacts of PD-L1 expression in tumor vs. stroma on survival in esophageal squamous cell carcinoma
Authors: Murakami Tomohiro , Furuhashi Satoru , Sakai Yuuki , Sekimori Kenichi , Haneda Ryoma , Booka Eisuke , Matsumoto Tomohiro , Kikuchi Hirotoshi , Hiramatsu Yoshihiro , Takeuchi Hiroya
Published: March 2024

Background: Esophageal squamous cell carcinoma (ESCC) has high incidence and recurrence rates, particularly in advanced stages. While the combined positive score (CPS) and tumor proportional score (TPS) are standard benchmarks for PD-L1 assessment in ESCCs, they face challenges such as reliance on subjective human interpretation and the uncertain clinical significance of strong staining intensities. Our study utilizes H-scores for PD-L1 expression and separates analysis of tumor and stroma, providing additional layers of information that complement current methods and contribute to a more comprehensive understanding of the role of PD-L1 in ESCC.

Methods: This retrospective single-center cohort analysis involved 194 cases of ESCC who underwent surgical resection. We performed a comprehensive evaluation of PD-L1 expression within the tumor and stroma using whole slide images (WSI). QuPath image analysis software was used to classify regions as tumor or stroma and quantify the PD-L1 expression H-score.

Results: Using optimal H-score cutoffs determined from the minimum P-value method, the Kaplan-Meier survival analysis showed that higher PD-L1 expression was significantly linked with better post-operative survival across all compartments. This correlation was most pronounced in the stroma (P<0.001). However, in multivariate Cox regression analysis, only high tumoral PD-L1 expression emerged as an independent predictor of favorable prognosis (HR=0.47, 95% CI: 0.27-0.81, P=0.007). The non-significant contribution of stromal PD-L1 in this model could be attributed to its association with advanced pT and pN stages, and the presence of lymphatic and venous invasion (P<0.001, respectively). Interestingly, stromal PD-L1 expression was associated with a longer duration of cytotoxic chemotherapy (cutoff 8 months, Median H-score 98.28 vs 55.24, P=0.026), but no significant correlation was observed with the duration of immune checkpoint inhibitor treatment.

Conclusions: The study underscores the complex role of PD-L1 in ESCC, with tumoral PD-L1 expression emerging as an independent prognostic factor, and stromal PD-L1 expression found to be related with tumor progression and the duration of cytotoxic chemotherapy response.

Citation Format: Tomohiro Murakami, Satoru Furuhashi, Yuuki Sakai, Kenichi Sekimori, Ryoma Haneda, Eisuke Booka, Tomohiro Matsumoto, Hirotoshi Kikuchi, Yoshihiro Hiramatsu, Hiroya Takeuchi. Differential impacts of PD-L1 expression in tumor vs. stroma on survival in esophageal squamous 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 65.
Abstract 6518: BPM 31510: Targeting the tumor microenvironment (TME) via mitochondrial-mediated ROS production
Authors: Gesta Stephane , Nastke Maria D. , Nagpal Seema , Recht Lawrence , Kiebish Michael A. , Narain Niven R. , Modur Vijay R.
Published: March 2024

The tumor microenvironment (TME) consists of an enriched population of immune cells and milieu of factors that modulate key cellular processes such as angiogenesis, metabolism, apoptosis, migration, and proliferation. Previous studies have suggested that BPM 31510 induces ROS through high intra-cellular levels of ubidecarenone in aggressive cancer phenotypes both in vitro and in vivo through induction of mitochondrial ROS. Furthermore, we have previously observed efficacy of BPM 31510 in a highly aggressive in vivo orthotopic rat C6 glioma model where BPM 31510 was administered in combination with radiotherapy. In a pancreatic xenograft mouse model, we previously reported that BPM 31510 impacted the immune cells in the TME by increasing absolute number of infiltrated CD8+ T-cells and decreasing absolute number of infiltrated CD4+ T-cells. Moreover, an ex vivo study of PBMC’s from healthy volunteers suggests that BPM 31510 increases T-cell viability and function while also decreasing T-cell exhaustion. Currently, an ongoing first-line phase 2b study of BPM 31510 in glioblastoma in combination with radiotherapy and temozolomide will assess the clinical efficacy and potential for mechanistic synergy of multiple ROS-inducing mitochondrial mediated regimens on this aggressive cancer phenotype. BPM 31510 will be assessed in this study to provide further evidence for the impact of ROS on immunomodulation. Taken together, BPM 31510 increases mitochondrial ROS/OXPHOS in cancer cells while impacting TME-related immune cell modulation.

Citation Format: Stephane Gesta, Maria D. Nastke, Seema Nagpal, Lawrence Recht, Michael A. Kiebish, Niven R. Narain, Vijay R. Modur. BPM 31510: Targeting the tumor microenvironment (TME) via mitochondrial-mediated ROS production [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 6518.
Abstract 6523: TOX upregulation promotes a GPX4-dependent CD8+ T cell ferroptosis in tumor microenvironments
Authors: Li Jiang , Zhu Qian , Liu Xiufeng
Published: March 2024

Frequency and function of CD8+ tumor-infiltrating T cells (TILs) decide on clinical outcome of cancer immunotherapy; and TOX function as a crucial regulator of TIL dysfunction. In the present study, we found that multiplex factors, such as tumor cell, viral antigens and hypoxia, in tumor microenvironments (TME) induced CD8+ TIL ferroptosis by upregulating TOX. Single cell RNA-sequencing revealed that TOX modulated Havcr2, Pdcd1, Hmox1, Gpx4, and Ctsb transcription in human and murine CD8+ TILs. We further generated TOX conditional knockout in CD8+ T cell (Toxflox/floxCd8Cre, CKO) mice and the tumor-bearing CKO mice exhibited increased anti-tumor immunity and survival time. TOX upregulation increased reactive oxygen species (ROS), lipid peroxidation, and ferrous iron, leading to a GPX4-dependent CD8+ T cell ferroptosis. Genetic or antibody ablation of TOX, TIM-3, or HO-1 indicated that these molecules orchestrated CD8+ TIL ferroptosis by inducing iron overload and lipid peroxidation. Targeting TOX, PD-1, TIM-3, or ferroptosis boosted the anti-tumor suppression of tumor-specific T cell-based adoptive cell therapy (ACT) in murine tumor model. TOX, TIM-3 and GPX4 were prognostic predictors in human cervical cancer. This finding identifies a novel mechanism of tumor-induced CD8+ T cell ferroptosis underwent by TOX that provides new insights in improving TIL-based ACT immunotherapy.

Key words: TOX, CD8+ T cells, ferroptosis, tumor microenvironments, cancer immunotherapy

Citation Format: Jiang Li, Qian Zhu, Xiufeng Liu. TOX upregulation promotes a GPX4-dependent CD8+ T cell ferroptosis in tumor microenvironments [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 6523.
Abstract 6527: Fucosyltransferase 5 promotes immune evasion in ovarian cancer by suppressing double negative T cells
Authors: Fung S. W. , To Sally K. Y. , Hassan A. A. , Ip Phillip P.C. , Wong Alice S. T.
Published: March 2024

Emerging evidence suggests that aberrant glycosylation in cancer impact on various stages in the disease progression including immunomodulation, but the underlying mechanisms remain poorly understood. Our previous data demonstrated that fucosyltransferase 5 (FUT5), a glycosyltransferase responsible for the terminal step in synthesizing Lewis antigens, may contribute to peritoneal metastasis of ovarian cancer. In this study, using clinical samples of high grade serous ovarian cancer (HGSOC), the most common subtype, we found that high expression of FUT5 is associated with a worse outcome. By employing multiplex immunohistochemistry (IHC) to examine T cell subsets, we found a significant decrease in CD3+CD4−CD8− (double negative, DN) T cells in FUT5high (n=10) compared to FUT5low samples (n=10), while there is no difference in the abundance of CD8+ cytotoxic T cells, CD4+ helper T cells or CD4+Foxp3+ regulatory T cells. Tumor-infiltrating DN T cells has been shown to mediate potent anti-tumor response. In addition to their cytotoxic capabilities, DN T cells largely exhibit modulatory functions on other T cell subsets. To further investigate, we performed additional IHC staining and observed a significant increase in proliferating (Ki67+) CD8+ tissue resident memory cells, which are known to be important for cancer immunity. In addition, we observed a decrease in metastases in the FUT5 knockdown group, accompanied by an increase in DN T cells in ascites and omental metastatic tumors in humanised mice, as revealed by flow cytometry, confirming a direct immunomodulatory role of FUT5. Together, these findings reveal a novel role of FUT5 in promoting immune evasion by suppressing anti-tumor DN T cells, which could provide novel insights for immunotherapy in HGSOC, which has a low response rate to immune checkpoint inhibitors (This research is supported by RGC SRFS2223-7S05, HMRF 08192286 and LSCCB under the Health@InnoHK Program launched by ITC, HKSAR).

Citation Format: S. W. Fung, Sally K. Y. To, A. A. Hassan, Phillip P.C. Ip, Alice S. T. Wong. Fucosyltransferase 5 promotes immune evasion in ovarian cancer by suppressing double negative T 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 6527.
Abstract 6538: Modulation of human macrophage differentiation, phenotype and function in vitro as a strategy to characterize novel tumor microenvironment modulators
Authors: Castro Carla N. , Sahner Tamara , Obodozie Cynthia , Metzger Philipp , Weber Holger
Published: March 2024

Macrophage infiltration of the tumor microenvironment is a key process that can determine the success or failure of anti-tumor therapies. Thus, many immunooncology therapies are being developed to modulate the macrophage differentiation program towards the anti-tumor M1 subset, while hindering the M2 subset associated with tumor progression. Monocyte-derived macrophages comprise a crucial in vitro cellular tool to evaluate the plasticity potential between the different polarization states. Several hurdles like their in vitro adherence, low cell number yield and the donor-to-donor variability pose technical challenges when using in vitro differentiated macrophages for compound screening and titration or functional assays.

At Reaction Biology we have established human macrophage assay pipelines to evaluate the novel macrophage polarization compounds in vitro. By isolating monocytes from frozen PBMC stocks it is possible to have access to the same donor or group of donors PBMC for repetitive analysis. We have developed a differentiation protocol that allows us to use different plate format from 6-well to 48 well plates, and thus increase and modulate the throughput according to the required readout.

The effect of therapeutic compounds can be analyzed by flow cytometry. Our data shows that human primary monocytes grown under M1 polarizing conditions express high levels of CD86 and CD80 in contrast to those cultivated under M2 polarizing conditions, with high expression of CD163, CD206, and CD209. Cell culture supernatant can be used to determine cytokine secretion. The functionality of the different macrophage subtypes can be further investigated using a pH-sensitive phagocytosis tracker, like pHRodo-Zymosan or pHRodo-Ecoli, which shows differential uptake according to differentiation profile. Moreover, treated macrophages can be used in coculture with T cells to investigate their capability to foster or inhibit an immune response.

Our data shows the value of monocyte-derived macrophage assays in the evaluation and efficacy assessment of TME modulators.

Citation Format: Carla N. Castro, Tamara Sahner, Cynthia Obodozie, Philipp Metzger, Holger Weber. Modulation of human macrophage differentiation, phenotype and function in vitro as a strategy to characterize novel tumor microenvironment modulators [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 6538.
Abstract 666: ASTX295 engages p53-mediated apoptosis and an inflammatory response in patient derived mesothelioma explants
Authors: Fennell Dean Anthony , Dzialo Joanna , Rogel Jan , Faulkner Daniel , Nusrat Nada , Bzura Aleksandra , Kutywayo Kudzayi , Wells-Jordan Peter , Poile Charlotte , Biondo Andrea , Sims Martin , Nakas Apostolos , Luo Jin-Li , Zhang Min , Ahn Maria
Published: March 2024

Mesothelioma is a universally lethal, rare cancer caused by asbestos that is lacking effective targeted treatments, particularly in the relapsed setting. P53 is predominantly wildtype (WT 83%) but is likely restrained by MDM2 particularly in the context of 9p21 deletion, a common, clonal somatic event affecting around half of all mesotheliomas that results in deletion of the MDM2 suppressor ARF. 9p21 deletion is also associated with a cold, immunosuppressed microenvironment. Unleashing p53WT by inhibiting its interaction with MDM2 has therapeutic potential in mesothelioma. To test this hypothesis, we employed live patient derived explants (PDEs) as a model that reflects the genomic inter-patient heterogeneity of mesotheliomas, and harbours an intact tumour microenvironment. Between August 2017 and April 2021 a total of 71 patients were consented prior to extended pleurectomy decortication, and PDEs were harvested at the time of surgery. PDEs were then cultured and treated with ASTX295, an inhibitor of p53-MDM2 interaction, using two concentrations (0.5 and 1 micromolar) and two timepoints (48 and 72 hours). PDEs passing quality control were subjected to spatial profiling using multiplex immunofluorescence microscopy. PDEs harbouring p53WT showed ASTX295-induced p21 (CDK1A) upregulation, which correlated with induction of apoptosis (p=0.04). PDE rank-order sensitivity was conserved across different doses and exposure-times. Transcriptome analysis confirmed ASTX295 induced p53 pathway activation in conjunction with a pro-inflammatory phenotype; both of which were absent in one PDE harbouring an inactivating p53 single nucleotide variant. Constitutive epithelial mesenchymal transition (EMT) was enriched in responding PDEs, as well as MDM2 inhibitor sensitive mesothelioma cell lines. 9p21 deletion (revealed by exome sequencing) was detected in both responding and non-responding PDEs. In summary, inhibition of MDM2-P53 interaction triggers robust p53 activation and a pro-inflammatory phenotype, which is potentiated in EMT enriched mesothelioma PDEs. ASTX295 is currently under clinical investigation (NCT03975387).

Citation Format: Dean Anthony Fennell, Joanna Dzialo, Jan Rogel, Daniel Faulkner, Nada Nusrat, Aleksandra Bzura, Kudzayi Kutywayo, Peter Wells-Jordan, Charlotte Poile, Andrea Biondo, Martin Sims, Apostolos Nakas, Jin-Li Luo, Min Zhang, Maria Ahn. ASTX295 engages p53-mediated apoptosis and an inflammatory response in patient derived mesothelioma explants [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 666.
Abstract 6673: Tumor microbial burden is regulated by mast cells and determines immunotherapy responses
Authors: Rajaei Hajar , Jang Jeong-Hoon , Liu Haoyue , Faraoni Erika Y. , Le Roux Olivia , Chandra Vidhi , Tahan Virginia , Li Le , Riquelme Erick , White James Robert , Diaz Luis A. , McAllister Florencia
Published: March 2024

Immune checkpoint inhibitors (ICI) have notably improved overall survival rates across various cancers, particularly in cases of mismatch repair deficient cancer (MMRd). However, numerous factors influence patient response following ICI treatment. Beyond genetic factors, mutations, and levels of immune cell infiltration, several studies highlight the correlation between the gut microbiome and treatment response rates. Furthermore, specific bacterial compositions have been observed to shift during therapeutic interventions. Notably, studies have demonstrated that patients who used antibiotics before and during ICI treatment exhibited lower progression-free survival and overall survival, serving as evidence for this association. Our previous investigations elucidated the impact of distinct tumor microbial burdens on modulating immune activation. Consequently, our hypothesis posits the substantive involvement of the interplay between tumor microbial burden and the immune system response to ICI treatment.

We evaluated the presence of intra-tumoral microbes within Colorectal cancers (CRC) by examining TCGA data. Patients with elevated microbial levels demonstrated heightened immune activity and better survival rates. Using cybersport analysis, we validated increased mast cell infiltration in CRC patients with abundant microbes. Quantification involved assessing bacterial burden through 16s rRNA via FISH staining and mast cell counts using tryptase via IHC staining. Reducing bacterial load in MC38 cancer model, achieved by locally administering antibiotics, led to a diminished immune response when PD-1 was introduced to these mice. Cross-referencing TCGA data, we identified upregulated genes in CRC patients with high microbial burden and downregulated genes in mice receiving local antibiotics after MC38 cell implantation. The common genes were associated with immune responses, suggesting a strong correlation between bacterial burden and immune activity in CRCs. In conclusion, the high burden of bacteria in CRC improves immune response to ICI and increases the infiltration of mast cells, which all contribute to better survival rates.

Citation Format: Hajar Rajaei, Jeong-Hoon Jang, Haoyue Liu, Erika Y. Faraoni, Olivia Le Roux, Vidhi Chandra, Virginia Tahan, Le Li, Erick Riquelme, James Robert White, Luis A. Diaz Jr., Florencia McAllister. Tumor microbial burden is regulated by mast cells and determines immunotherapy 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 6673.
Abstract 6756: Our RNA production platform and the associated tools facilitate the development of RNA-based vaccine
Authors: Bosso-Lefèvre Célia , Cirri Erica , Mennesson Eric , Szymczak Dimitri , Carpentier Flavien , Foucher Alexandra , Komarkova Alzbeta , Rochet Maxime , Vindrios Armelle , Goulay Romain
Published: March 2024

mRNA vaccines have shown their full potential in the Covid-19 pandemic. The application of these technologies for the treatment of cancers represents significant hope, but clinical effectiveness remains to be demonstrated. For this purpose, researchers require high quality production of vaccine mRNA and accurate and cost-saving test tools that are adapted to oncology research. Since 2021, Tebubio has developed a miniscale RNA production platform for providing RNAs (from 100 µg to 1 mg) to researchers around the world. This service is completed by offers on RNA delivery solutions using lipid nanoparticles (LNPs) and cellular tests with biomarker analysis. Through an ingenious design, our DNA matrix for mRNA is easily transferable for GMP production for clinical studies. Recently, Tebubio has developed DNA matrices for circular RNA production. Indeed, circular RNA has many advantages by being less immunogenic and more stable than linear RNA. We compared the quality and the quantity of CAP1 capped linear RNA and circular RNA produced from our DNA templates. We also assessed the stability of both RNAs expressing GFP and the typical tumor antigen, p53, and their relative expression into antigen-presenting cells (APCs). Finally, we quantified the response of the APCs expressing p53 by using our biomarker multiplex analysis system. This new type of RNA and its efficiency testing in APCs will constitute a new addition to our pipeline of RNA production and testing for preclinical studies.

Citation Format: Célia Bosso-Lefèvre, Erica Cirri, Eric Mennesson, Dimitri Szymczak, Flavien Carpentier, Alexandra Foucher, Alzbeta Komarkova, Maxime Rochet, Armelle Vindrios, Romain Goulay. Our RNA production platform and the associated tools facilitate the development of RNA-based vaccine [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 6756.
Abstract 6812: Durable control of brain tumors by glioma inhibitory macrophages and IL33
Authors: Menon Shyam V. , Lun Xueqing , Zeng Peipei , Zhang Jianbo , Ahn Bo Young , Yu Henry , Poole Alisha , Dang Ngoc Ha , Osz Katalin , Chan Jennifer A. , Quail Daniela F. , Robbins Stephen M. , Senger Donna L.
Published: March 2024

Glioblastoma is the most common and deadly form of brain cancer. Even with aggressive treatment including surgery, chemotherapy, and radiotherapy, survival outcomes for newly diagnosed glioblastoma patients remains less than two years. Novel high throughput omics technologies have expanded our understanding of the role of innate immune system in brain tumors, that are generally believed to drive glioma progression and enable evasion of the adaptive immune system. However, targeting of this axis in the clinic remains an unmet opportunity. Previously, we discovered that the dual-function (secreted and nuclear) cytokine IL-33 is a crucial regulator of the inflammatory microenvironment that promotes glioma tumorigenesis through phenotypic and functional changes in the innate immune cell repertoire. Strikingly, when IL-33 is prevented from entering the nucleus, by deletion of its nuclear localization sequence (ΔNLS IL-33), but is still secreted, in vivo tumor growth is dramatically inhibited resulting in prolonged long-term survival. Using multiplex immunohistochemistry and spatial transcriptomics with temporal resolution across different stages of tumor progression, we identified a population of glioma-inhibitory macrophages (GIMs) unique to this suppressive environment. Assessment of GIMs in xenografts generated from patient brain tumor initiating cells found an enriched presence of these cells in xenografts with long-term survival (greater than 300 days) versus short-term survival (less than 100 days). The ability of GIMs to inhibit glioma progression was demonstrated when tumors established using a combination of ΔNLS IL-33 expressing cancer cells together with highly tumorigenic cells resulted in a growth inhibitory environment that significantly extended survival. A deeper molecular characterization of this phenotype and development of clinical strategies are currently underway.

Citation Format: Shyam V. Menon, Xueqing Lun, Peipei Zeng, Jianbo Zhang, Bo Young Ahn, Henry Yu, Alisha Poole, Ngoc Ha Dang, Katalin Osz, Jennifer A. Chan, Daniela F. Quail, Stephen M. Robbins, Donna L. Senger. Durable control of brain tumors by glioma inhibitory macrophages and IL33 [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 6812.
Abstract 6864: Tumor suppressor function of the ubiquitin ligase Siah1a in melanoma is mediated by myeloid derived suppressor cells
Authors: Scortegagna Marzia , Du Yuanning , Feng Yongmei , Ronai Ze'ev
Published: March 2024

Growing evidence supports the important role of myeloid-derived suppressor cells (MDSC) in melanoma progression and response to therapy. MDSC contributes to a pro-tumorigenic phenotype, yet the mechanistic basis for the immune suppressor properties acquired by MDSC remains largely unknown. Mammals have two homologous Siah genes, Siah1 (Siah1a and Siah1b in mice) and Siah2. In the context of melanoma, the ubiquitin ligases Siah1a and Siah2 have melanoma-intrinsic and -extrinsic (immune) functions. Correspondingly, ablation of Siah1a/2 in melanoma or its microenvironment attenuates melanoma development in a number of mouse melanoma models. Given that number of macrophage clusters infiltrated into melanoma when grown in Siah2 KO mice, we set to assess macrophage function in melanoma. Selective ablation of Siah1a or Siah2 in macrophages, using Lyz2Cre, revealed that Siah1a but not Siah2 elicits a tumor suppressor function in melanoma. Inoculation of mouse melanoma Yummer1.7 cells (Braf mutated and Pten deleted) in mice lacking Siah1a in macrophages, resulted in bigger melanoma tumors compared to melanoma grown in either WT or mice in which macrophages were ablated of Siah2. FACS analysis of melanoma tumors grown in mice harboring Siah1a mutant macrophages revealed a significant increase in MDSC, which coincided with a decrease in CD4+ and CD8+ cells, compared with WT mice. These observations suggest that a lack of Siah1a in macrophages leads to an expansion of MDSC that affects surrounding immune cells, including T cells. RNA-seq analysis of MDSC that were differentiated in vitro from bone marrow cells of WT or Siah1a ablated macrophage mice revealed increased expression of genes involved in proliferation and alternative macrophage activation in MDSC lacking Siah1a when compared to the WT genotype. Mapping mechanisms underlying Siah1a tumor suppressor function is expected to reveal novel regulatory cues in melanoma control by the MDSC population while mapping novel means for stratifications of melanoma to therapy, and possibly new means for therapy of this tumor type.

Citation Format: Marzia Scortegagna, Yuanning Du, Yongmei Feng, Ze'ev Ronai. Tumor suppressor function of the ubiquitin ligase Siah1a in melanoma is mediated by myeloid derived suppressor 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 6864.
Abstract 6904: Model-derived progression-free survival (mPFS): A better metric for patient-derived xenograft studies
Authors: Chen Andrew , Stoddard Madison , Yuan Lin , Van Egeren Debra , Chakravarty Arijit , Bottino Dean
Published: March 2024

Patient-derived xenografts (PDX) are a powerful assay system for translational prediction of therapeutic potential for experimental therapeutics. The primary readout from PDX models is tumor shrinkage, measured by the ratio of treated/control tumor volume. This readout corresponds loosely to the Objective Response Rate (ORR) metric used in clinical trials, in that it is a readout of drug effect on the sensitive subclones within a tumor. In prior work, we have shown that there is a paradoxical relationship between short-term tumor response and progression-free survival (PFS). While ORR is the primary measure utilized in the Phase II to III transition in clinical development, approval hinges on survival metrics, and the disconnect between ORR and PFS creates a potential risk of late-stage failures for experimental anticancer therapeutics. Thus, it is of interest to understand whether there are alternative approaches to analyzing PDX data that can enable the assessment of therapeutic potential in terms of a projected PFS. In this simulation study, we will examine the accuracy of progression-free survival (PFS) estimates obtained directly from observation during a PDX study and compare their accuracy with the accuracy of PFS estimates derived using a mathematical model-based approach that relies on a kinetic model of tumor subclone growth (model-based PFS, or mPFS) fitted directly to PDX tumor growth and rebound kinetics under treatment. We generated our test dataset using a mathematical model of tumor kinetic growth to simulate xenograft data using fitted parameters derived from literature, adding in experimental error consistent with prior experimental measurement-derived variability. We used the simulated raw data to calculate an observed PFS as well as mPFS derived from fitting the tumor clonal kinetic model to the raw data in a blinded fashion. Our results show that the empirical PFS from PDX models is subject to overestimation, as a function of the observation time interval. On the other hand, mPFS is significantly less biased and more accurate, but is subject to some logistical constraints on sampling. Our work demonstrates the practical translational utility of a novel analysis method (mPFS) in deriving estimates of progression-free survival from PDX model data.

Citation Format: Andrew Chen, Madison Stoddard, Lin Yuan, Debra Van Egeren, Arijit Chakravarty, Dean Bottino. Model-derived progression-free survival (mPFS): A better metric for patient-derived xenograft studies [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 6904.
Abstract 6935: Non-genetic routes of lung cancer evolution
Authors: Ciriello Giovanni , Tavernari Daniele , Varrone Marco
Published: March 2024

Cancer cell plasticity underlies the progression of several solid tumors. In lung adenocarcinoma, morphological changes characterizing the transition from indolent to aggressive disease exhibit profound epigenetic and transcriptional reprogramming1. However, the extent, features, and drivers of cancer cell plasticity in the progression of human lung adenocarcinoma is still largely unexplored. Here, we assembled and analyzed a meta-cohort of 119 human lung tumors analyzed by single-cell RNA-sequencing, for a total of ~730,000 cells. Cancer cell heterogeneity was the result of differential activation of 17 transcriptional programs associated with common cancer phenotypes, such as proliferation, cell migration, and response to hypoxia, as well as alveolar lineage identity (AT2). In particular, AT2-specific expression of MHC-II was down-regulated with the progression of the disease and markedly reduced in KEAP1 and/or STK11 mutated samples, providing a rationale for the association between these mutations and immunotherapy resistance. Co-activation of transcriptional programs clustered tumor cells in 4 major cell states, which emerged with the progression of the disease. To explore spatial distribution of different cancer cell states, we generated and analyzed multiple spatial transcriptomics and proteomics lung adenocarcinoma cohorts. To this purpose we developed a new algorithm called CellCharter2. CellCharter identified distinct cancer-enriched niches within individual samples, corresponding to the cancer cell states that we discovered in the scRNA-seq cohort and exhibited specific interactions with the tumor microenvironment (TME). In particular, we identified a cancer cell state characterized by response-to-hypoxia and migratory phenotypes, which spatially segregated from highly proliferative cancer cell niches and formed specific interactions with tumor associated neutrophils. This cell state was enriched in advanced primary samples, it uniquely characterized metastatic samples, and was an independent marker of poor prognosis across multiple independent datasets. Overall, our work uncovered cell plasticity trajectories associated with the progression of lung adenocarcinoma and shed new light into the tumor-TME interactions at their origin. 1 Tavernari et al., Cancer Discovery, 20212 Varrone et al, Nat. Genetics, (in press)

Citation Format: Giovanni Ciriello, Daniele Tavernari, Marco Varrone. Non-genetic routes of lung cancer evolution [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 6935.
Abstract 6953: Wnt2b deficiency exacerbates colitis and leads to increased tumorigenesis in mice
Authors: Oliveira Luiz Fernando Silva , O'Connell Amy E.
Published: March 2024

Colitis-associated cancer (CAC) is considered the most severe complication of inflammatory bowel disease (IBD). It has been demonstrated that WNT2B deficiency leads to severe intestinal impairment in humans and predisposes to colitis in mice. Evaluating a human cohort from The Cancer Genome Atlas (TCGA), we observed that low expression of WNT2B is associated with poor prognosis of patients with colon cancer. However, the functional roles of WNT2B in CAC development remain unclear, and we hypothesized that WNT2B is involved in the resistance to CAC development during long-term colitis. Thus, we model CAC development using Wnt2b deficient mice subjected to mutagenesis induction with 10 mg/kg Azoxymethane (AOM) and a long-term colitis protocol with three cycles of 2.5% Dextran Sodium Sulfate in the drinking water for three days, followed by a recovery period with autoclaved water. We observed that Wnt2b KO mice had increased susceptibility to colitis and more significant body weight changes than WT mice, especially in the first and second recovery cycles of colitis recovery. The maximum weight loss and disease activity index (DAI) were significantly higher in KO than in WT mice. Interestingly, Wnt2b KO mice developed more tumors, which were more extensive than those observed in WT. Moreover, the histopathological analysis showed that Wnt2b KO had the highest score for ulceration, aberrant crypt foci, and immune cell infiltration. Our data suggest a protective role for WNT2B, conferring resistance to tumor development during colitis. Furthermore, our data provides new insights into the functional roles of Wnt ligands in colon cancer. A better understanding of the factors involved in CAC etiology is critical for improving diagnosis and developing new targeted therapies. We believe WNT2B may emerge as one of these factors and offer novel targets for improved colorectal cancer management.

Citation Format: Luiz Fernando Silva Oliveira, Amy E. O'Connell. Wnt2b deficiency exacerbates colitis and leads to increased tumorigenesis in mice [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 6953.