bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2824: Establishing prostate cancer models for orthotopic and bone metastatic growth using the 22Rv1cell line
Authors: Zdrojewska Justyna , Fagerlund Katja , Mäki-Jouppila Jenni H. , Suominen Mari I.
Published: March 2024

Prostate cancer is the second most common cancer in men with new cases diagnosed in 1.4 million men each year. Luckily the 5-year survival rates in developed countries are high reaching over 90%. However, approximately one third will develop a metastatic disease. In metastatic patients, prostate cancer almost always progresses despite the androgen deprivation therapy and is then referred to as “castration-resistant (mCRPC)”. Bone is involved in 80% of patients with metastasis, and the bone lesions are typically osteoblastic. The 22Rv1 human prostate carcinoma cell line is androgen sensitive and shown to express androgen receptor (AR). They also express low levels of prostate-specific membrane antigen (PSMA). The aim of this study was to establish orthotopic and intratibial preclinical in vivo prostate cancer models that can be used in drug development when targeting cancer cells and their local environment. Male athymic nude mice (5-6 weeks old) and NOG mice (over 20 weeks old) were used in the study. 2.5 × 105 22Rv1 cells (ATCC) were inoculated orthotopically into the prostate of NOG mice, and 5 × 105 cells were inoculated intratibially into the bone marrow cavity of athymic nude mice. Tumor growth was followed by PSA measurements every second week using Human PSA ELISA assay. In addition, in the intratibial model, tumor-induced bone changes were monitored by X-ray imaging of the hind limbs. Prostates and hind limbs were collected at sacrifice, fixed in 10% NBF, and processed to paraffin blocks for further histological analysis. Sections of prostate were stained with hematoxylin-eosin (HE) and AR. Tumor-bearing and contralateral (healthy) tibias were stained with HE - OrangeG, MGT, TRAP, and AR. The observed tumor take rate was 92% in the orthotopic and 100% in the intratibial models. Confirmed by IHC, tumors formed in both the orthotopic and intratibial models expressed AR. 22Rv1 cells formed osteoblastic - lytic mixed bone lesions in the intratibial model. Based on lesion areas, randomization of the tumor bearing mice in the intratibial model can be done after 2 weeks from cancer cell inoculation. Taken together, the 22Rv1 prostate cancer models are relatively fast growing, express AR and present good take rates. Furthermore, the intratibial model represents robust tumor-induced changes in bone with strong osteoblastic component. Thus, these models have several advantages in efficacy studies of novel drug candidates for prostate cancer.

Citation Format: Justyna Zdrojewska, Katja Fagerlund, Jenni H. Mäki-Jouppila, Mari I. Suominen. Establishing prostate cancer models for orthotopic and bone metastatic growth using the 22Rv1cell line [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 2824.
Abstract 2877: Enhancing diagnostic precision in peritoneal cancer metastasis: Photodynamic diagnosis-guided laparoscopy in a rabbit model
Authors: Kim Hyoung-Il , Rivera-Piza Adriana , Lee Sunghwan
Published: March 2024

Introduction: Precise diagnostic workup is crucial for developing effective treatment strategies in cancer patients. Peritoneal carcinomatosis, often missed in preoperative CT scans and conventional laparoscopy, poses diagnostic challenges. This study aimed to assess the diagnostic accuracy of staging laparoscopy using photodynamic diagnosis (PDD) with the photosensitizer phonozen activated at 405 nm in a rabbit model of peritoneal carcinomatosis.

Methods: Female New Zealand white rabbits (16-20 weeks old) were utilized to establish the model through peritoneal inoculation of VX2 sarcoma cells, resulting in distinct solid-tumor nodules for laparoscopic evaluation. A customized dual-emission laparoscope, capable of both white-light and 405 nm blue-light, was employed for PDD. To minimize blue-light background interference, a 550 nm long-pass filter was placed between the laparoscope and the video camera, optimizing the process. The PDD-enhanced diagnostic laparoscopy comprised a tripartite approach: 1) initial peritoneal cavity exploration under white-light and labeling of suspect nodules, followed by 2) utilization of blue light with the long-pass filter to identify red-light emissions from distinctly labeled tumor cells, and 3) open laparotomy served to palpate the peritoneal surface and identify additional or missed tumor nodules.

Results: Analysis of data from 12 rabbits with 267 tumor nodules revealed that sensitivity and specificity of diagnostic laparoscopy for detecting tumor nodules increased from 84.9% and 18.8% with white light alone to 90.8% and 25.0% when aided by PDD, respectively. These findings underscore the substantial improvement in diagnostic accuracy achievable by combining the rabbit model of peritoneal carcinomatosis with PDD in laparoscopic procedures.

Conclusion: The heightened sensitivity and specificity observed in this study hold significant promise for positively impacting clinical practice, providing a more accurate and effective approach to the diagnosis and management of peritoneal carcinomatosis.

Citation Format: Hyoung-Il Kim, Adriana Rivera-Piza, Sunghwan Lee. Enhancing diagnostic precision in peritoneal cancer metastasis: Photodynamic diagnosis-guided laparoscopy in a rabbit model [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 2877.
Abstract 2884: Resistance to pan-FGFR inhibition is determined by the EMT phenotype associating with clinical outcome in HNSCC
Authors: Broghammer Felix , Gouda Mahesh , Korovina Irina , Brunner Cornelia , Coppes Robert P. , Gires Olivier , Seifert Michael , Cordes Nils
Published: March 2024

Receptor tyrosine kinases (RTK) and integrins coalesce at focal adhesions. These cell membrane areas serve as huge signaling hubs critically contributing to central aspects of cancer cell survival and therapy resistance. Despite the fact that these receptors mutually interact, co-dependencies between these receptors and associated therapeutically exploitable vulnerabilities remain largely unclear in HPV-negative head and neck squamous cell carcinoma (HNSCC). Here, we evaluated the cytotoxic and radiochemosensitizing potential of targeting 10 RTK and β1 integrin in up to 20 different 3D matrix grown HNSCC cell models. RNA sequencing and protein-based biochemical assays were performed for molecular and pathway characterization. Bioinformatically identified transcriptomic signatures were applied to patient cohorts to show clinical relevance. Our observations demonstrate that fibroblast growth factor receptors (FGFR 1-4) present with the strongest cytotoxic and radiosensitizing potential, both as monotherapy and in combination with β1 integrin inhibition, surpassing the efficacy of the other investigated RTK. Pharmacological pan-FGFR inhibition elicited a variable response spectrum ranging from cytotoxicity/radiochemosensitization to resistance/radioprotection. Transcriptomic characterization revealed an association of these contrasting responses to FGFR inhibition with a mesenchymal-to-epithelial transition (MET) for sensitive cell models and a partial epithelial-to-mesenchymal transition (EMT) for resistant cell models. Accordingly, deactivation of EMT associated kinases like EGFR, PKC and PAK proved effective in diminishing the adaptive FGFR-driven resistance. Importantly, the translation of the adaptive resistance profiles to HNSCC patient cohorts showed its prognostic value and provided conclusive validation of the presence of EMT-related vulnerabilities that can be strategically used for therapeutic intervention. In conclusion, our study demonstrates that pan-FGFR inhibition induces both a highly beneficial radiochemosensitizing and a detrimental radioprotective effect in HNSCC cell models. Adaptive EMT-associated resistance appears to be of clinical importance, and we provide effective molecular approaches to exploit this therapeutically.

Citation Format: Felix Broghammer, Mahesh Gouda, Irina Korovina, Cornelia Brunner, Robert P. Coppes, Olivier Gires, Michael Seifert, Nils Cordes. Resistance to pan-FGFR inhibition is determined by the EMT phenotype associating with clinical outcome in HNSCC [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 2884.
Abstract 2888: Sensitization of radiation resistant colon cancer - The oxygenated microbubble hydrogel approach
Authors: Jose Ashok David , Chong Celine Hui-Ning , Jaiswal Jagdish , Wu Zimei , Thakur Sachin Sunil
Published: March 2024

Background: Hypoxia, a state of reduced oxygen that develops within the tumor due to its irregular vasculature, could result in treatment resistance. Mounting evidence suggests that reoxygenation of the tumor could improve outcomes of conventional cancer therapies. Our approach combats hypoxia using oxygenated lipid microbubbles (OMB) loaded in a temperature sensitive gel. The OMB would carry the oxygen while the gel would sustain its release into the tumor microenvironment.

Objectives: To formulate an oxygen loaded MB dispersed in a temperature sensitive poloxamer hydrogel for intratumoral administration.

Methods: OMB were generated by first preparing a liposomal mixture DSPC:DSPE-PEG2000, which was dispersed in a thermosensitive poloxamer hydrogel (P407:P188). This was pressurized with oxygen and vortexed in a gas-tight vial. Characterizations included OMB size distribution, injectability, thermosensitivity, oxygen loading and release, and the impact of the formulation on efficacy of radiotherapy against a colon cancer cell line (HCT116) was evaluated.

Results: DSPC:DSPE-PEG2000 liposomes at a molar ratio of 94:6 dispersed in P407:P188 (21:6.5 %w/w) generated OMB with a size distribution in the acceptable range of 0.8-8 µm. Formulations were within the established limits of injectability (F<38N) at room temperature, and gelled near physiological temperatures enabling a sustained release of oxygen.. The formulation co-treatment enhanced radiotherapy significantly as evidenced by the remarkable reductions of clonogenic survival rates in both hypoxic and normoxic HCT116 cells (reduction by 78% vs 68% compared to just their respective radiated controls; p<0.0001 for both cases).

Conclusion: Reoxygenation with a newly developed OMB hydrogel formulation effectively sensitized HCT116 to radiotherapy in vitro. Studies are underway to explore the importance of reoxygenation rate and extent for optimal tumor sensitization.

Citation Format: Ashok David Jose, Celine Hui-Ning Chong, Jagdish Jaiswal, Zimei Wu, Sachin Sunil Thakur. Sensitization of radiation resistant colon cancer - The oxygenated microbubble hydrogel approach [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 2888.
Abstract 29: A genetically modified tumor-infiltrating lymphocytes product (GT216) enhanced anti-tumor efficacy against solid tumor by fine-tuning multiple negative immune regulators
Authors: Sun Jingwei , Tan Yiyang , Jin Jiahui , Wang Jingman , Chen Lingyun , Guo Fengbiao , Tan Yongchao , Xu Zhao , Liu Yarong
Published: March 2024

Adoptive cell therapy by tumor-infiltrating lymphocytes (TILs) has demonstrated promising clinical benefits for patients with solid tumors. However, the large-scale expansion during manufacture may drive hypofunction or exhaustion status of the final TIL product, leading to impaired anti-tumor efficacy and persistence post infusion. Grit Biotechnology designed a genetically engineered TIL product (GT216) to overexpress an intracellular protein that is induced by antigen-specific T cell response and mediates the degradation of multiple immunoregulatory molecules, which releases the therapeutic potential of TIL with enhanced cytotoxicity as well as persistence in vitro and in vivo. Multiple vector construct designs of GT216 were compared and the best design was selected based on stable and efficient expression of surrogate marker in TILs. GT216 could be successfully manufactured by Grit’s StemTexp® and StaViral® platforms with good memory phenotype and no signs of overactivation or exhaustion. In vitro functional analysis showed that GT216 demonstrated significantly increased cytotoxicity and cytokine production when cocultured with tumor cells and better tumor control ability during a serial killing assay than conventional TILs. Notably, GT216 TILs eradicated tumor growth with low IL-2 support in NOG mice inoculated with HLA-matched tumor cells while conventional TILs showed limited tumor control with high IL-2, corelated with their better infiltration and persistence in tumor and periphery. In summary, GT216 demonstrated enhanced anti-tumor efficacy and persistence as well as reduced IL-2 dependency in vitro and in vivo, supporting the clinical evaluation of GT216 as a next-generation TIL therapy in treatment of refractory solid tumors.

Citation Format: Jingwei Sun, Yiyang Tan, Jiahui Jin, Jingman Wang, Lingyun Chen, Fengbiao Guo, Yongchao Tan, Zhao Xu, Yarong Liu. A genetically modified tumor-infiltrating lymphocytes product (GT216) enhanced anti-tumor efficacy against solid tumor by fine-tuning multiple negative immune regulators [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 29.
Abstract 2900: BRAFi-induced epigenetic switch drives the reprogramming of resistant cancer-associated fibroblasts
Authors: Xiao Yao , Zhou Linli , Zhang Yuhang
Published: March 2024

Cancer-associated fibroblasts (CAFs) are a potential target for optimizing therapeutic strategies against melanoma. However, a major unknown still exists in CAFs, which is how CAFs maintain and even reinforce their functions in drug therapy and influence melanoma cell drug sensitivity. Yes-associated protein 1 (YAP1) is the master regulator that shuttles between the cytoplasm and nucleus in CAFs. Apparently, proteins associated with nuclear YAP1 in CAFs when treated with BRAF inhibitor (BRAFi) can potentially influence tumor drug response. Here we unveil that CAFs require the YAP1 function to proliferate, migrate, remodel the cytoskeletal machinery and matrix, and promote cancer cell invasion. Ablating YAP1 in CAFs increases the response of BRAF-mutant melanoma cells to BRAFi and MEK inhibitor (MEKi) in vivo and in vitro. Using an approach termed RIME (Rapid Immunoprecipitation Mass Spectrometry), we purified nuclear YAP1 and identified protein arginine methyl transferase 1 (PRMT1) as a major YAP1 binding partner in BRAFi-treated CAFs. Binding PRMT1 to YAP1 was confirmed by Co-immunoprecipitation and proximity ligation assay, and YAP1 deficiency in CAFs diminishes the nuclear accumulation of PRMT1, suggesting BRAFi-induced nuclear translocation of PRMT1 in CAFs requires the formation of YAP1 and PRMT1 complex. Silencing PRMT1 expression in CAFs not only deprives them of their ability to proliferate and to induce BRAF mutant melanoma cell resistance to BRAFi and MEKi. PRMT1 is a type I R-methyltransferase that mediates arginine methylation in human cells, which was known to be recruited to chromatin and exert its enzymatic activity to methylate

Arg3 of histone H4 (H4R3). Using Histone H4 Modification Multiple Assay, we observed a global increase in Histone H4 methylation, especially H4R3 methylation, in CAFs in response to BRAFi stimulation, suggesting increased chromatin unfolding and accessibility and transcription activation. When YAP1 or PRMT1 expression was silenced, H4R3 methylation was notably suppressed, indicating BRAFi-induced H4R3 methylation was indeed driven by the YAP1 and PRMT1 signaling axis. In conclusion, our data disclose a novel BRAFi-induced YAP1-PRMT1-mediated epigenetic mechanism that reprograms CAFs through H4R3 methylation-directed transcriptional activation to reinforce their drug-resistant functions and modulate melanoma cell drug sensitivity. Moreover, the discovery of PRMT1 as a key player in the intricate molecular mechanisms that govern epigenetic regulation in CAFs in response to BRAFi treatment suggest PRMT1 as a potential CAF target in cancer therapy.

Citation Format: Yao Xiao, Linli Zhou, Yuhang Zhang. BRAFi-induced epigenetic switch drives the reprogramming of resistant cancer-associated fibroblasts [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 2900.
Abstract 2922: Sensory innervation as a novel driver of ovarian cancer progression
Authors: Knarr Matthew , Cummins Katherine , Racordon Dusan , Reavis Hunter , Lippert Timothy , Hausler Ryan , Rawat Priyanka , Ryu Suyeon , Moon Jamie , Hoon Dave , Greenberg Roger , Vermeer Paola , Drapkin Ronny
Published: March 2024

One of the main challenges currently faced in ovarian cancer treatment is that the primary platinum/taxane therapy used to treat patients does not meaningfully extend survival. The overall survival for ovarian cancer patients with advanced disease is less than 30% with most patients recurring within 5 years of initial therapy. Once resistant disease develops there are few second line therapy options, which inevitably leads to disease progression. Thus, there is a critical need to identify new therapies that can overcome ovarian cancer chemoresistance and produce meaningful increases in patient survival. In recent years, new efforts have focused on targeting the tumor microenvironment (TME), the complex mixture of non-cancer cells that surround and support the cancer cells within the tumor. Different strategies have evolved to target the TME, such as immune checkpoint inhibitors or angiogenesis inhibitors. However, these TME targeting therapies have limited effect when used to treat ovarian cancer patients. Most ovarian tumors have a microenvironment that is highly immunosuppressive and do not respond or are resistant to angiogenesis inhibitors. Thus, new TME targeting therapies must be developed that can induce a therapeutic effect in ovarian tumors and can be used to treat most ovarian cancer patients. A novel TME component ripe for therapeutic targeting are the nerve fibers that infiltrate tumors in a process termed tumor innervation. Recent studies in several cancers have shown that tumor innervation can promote tumor growth/metastasis. However, in ovarian cancer the role of innervation in promoting cancer progression remains undefined. Here we show that Transient Receptor Potential cation channel subfamily V member 1 (TRPV1)+ sensory innervation plays a significant role in driving ovarian cancer growth and metastasis. Analysis of patient samples shows that sensory nerve fiber innervation is much higher in ovarian tumors vs benign reproductive tissue. In addition, ablation of TRPV1 sensory nerve fibers in vivo causes reduced tumor burden and prolongs survival in a syngeneic mouse model of ovarian cancer metastasis. Taken together, our results establish TRPV1+ sensory innervation as a novel driver of ovarian cancer growth/metastasis and a potential therapeutic target for ovarian cancer treatment.

Citation Format: Matthew Knarr, Katherine Cummins, Dusan Racordon, Hunter Reavis, Timothy Lippert, Ryan Hausler, Priyanka Rawat, Suyeon Ryu, Jamie Moon, Dave Hoon, Roger Greenberg, Paola Vermeer, Ronny Drapkin. Sensory innervation as a novel driver of ovarian cancer progression [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 2922.
Abstract 2965: GADD45B as a mechanism for enhanced treatment response with the combination of copanlisib and romidepsin in colorectal cancer
Authors: Maduscha Kennedy , Schmitz Alexa , DeStefanis Rebecca , Pasch Cheri , Deming Dustin
Published: March 2024

Background: Treatment options for molecular subtypes of colorectal cancer (CRC) are urgently needed, including for PIK3CA mutant CRC. Previous work in our lab demonstrated enhanced activity of copanlisib in combination with romidepsin in PIK3CA mutant CRC models. Here we investigate the induction of GADD45B as a mechanism of the enhanced induction of apoptosis seen with this treatment strategy.

Methods: RNA sequencing was done on the CRC 2D cell line, SW48PK (Horizon Discovery, SW48 PIK3CAH1047R/+ mutation) as well as PIK3CA mutant and wild-type patient derived cancer organoids (PDCOs) through the UW Biotechnology Center. All lines were treated with copanlisib, romidepsin, or combination and were compared with untreated controls. GADD45B gene expression was also confirmed on SW48PK, PIK3CA mutant, wild type, and PIK3CA and KRAS mutant PDCOs using RT-qPCR.

Results: RNA sequencing determined that there was an increase of GADD45B expression in the SW48PK 2D cell line as well as in PIK3CA mutant and wild-type PDCOs treated with the combination compared to untreated controls (average log2 fold change= 1.83). A significant increase in GADD45B expression was seen in the SW48PK combination treatment group compared to the control group at 6 hours (combination median fold change= 2.7, p= 0.045) and 24 hours (4.1, p< 0.001). For PIK3CA mutant PDCOs treated with the combination, there was significant increase in GADD45B expression at 6 hours (9.45, p= 0.005) and 24 hours (14.7, p= 0.002) compared to untreated control. In wild type PDCOs, there was a significant increase in GADD45B expression in the combination compared to untreated control at 6 hours (32.95, p=0.004) but not after 24 hours (2.6, p= 0.42). For KRAS mutant PDCOs, there was a significant increase in GADD45B expression in combination treated cells at 6 (9.9, p= 0.001) and 24 hours (3.3, p= 0.047), however, this increase was less than PIK3CA mutant PDCOs at 24 hours (3.3 vs 14.7).

Conclusions: Copanlisib in combination with romidepsin increases GADD45B expression in PDCOs and SW48PK. Further studies will determine if GADD45B is required for this treatment response.

Citation Format: Kennedy Maduscha, Alexa Schmitz, Rebecca DeStefanis, Cheri Pasch, Dustin Deming. GADD45B as a mechanism for enhanced treatment response with the combination of copanlisib and romidepsin in 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 2965.
Abstract 2966: Senescent cancer cell vaccines induce cytotoxic T cell responses targeting primary tumors and disseminated tumor cells
Authors: Liu Yue , Pagacz Joanna , Wolfgeher Donald J. , Kron Stephen J.
Published: March 2024

Diverse conventional cancer therapies, including genotoxic agents and cell cycle or cell division-targeting drugs, can trigger cancer cell senescence. Senescent cells (SnCs) induced by cancer therapy often display unrepaired chromosomal damage but persist indefinitely. SnCs remain metabolically active and display distinct alterations in transcription, secretion, and membrane protein expression/presentation. While initially viewed as a favorable outcome and likely tumor-suppressive mechanism, therapy-induced senescence has more recently been recognized as contributing to resistance, recurrence and metastasis. Adverse effects may be mediated in part by release of inflammatory mediators as components of the senescence-associated secretory phenotype (SASP). Recent studies have argued for reconsidering the potential benefits of therapy-induced senescence, especially in modulating the tumor microenvironment to potentiate anti-tumor immunity and potentiate immunotherapy. We have explored the potential for SnCs to serve as vaccines, building upon prior findings where we demonstrated the immunogenic senescence triggered by the combination of ionizing radiation (IR) and the PARP1/2 inhibitor veliparib. We find that SnCs are avidly taken up by type I conventional, CD11c+/CD103+ dendritic cells (DCs), promoting their activation and maturation. Thereby, SnCs promote DC function in T cell priming and stimulation. The capacity of SnCs to activate DCs depends on how the SnCs are formed, with our results confirming IR+veliparib induces high immunogenicity and implicating a distinct SASP in these effects. On the other hand, blocking STING signaling limits SnC activation of DCs. In vivo experiments with the murine tumor models CT26 and 4T1 suggest that both SnCs and SnC-pulsed DCs serve as effective anti-tumor vaccines. They not only confer protective immunity against tumor engraftment but also act as therapeutic vaccines, inhibiting both primary and disseminated tumor growth, and synergize with radiotherapy and immune checkpoint blockade. While direct administration of tumor-derived SnCs to patients may raise safety concerns, pulsing autologous DCs with tumor SnCs may help drive anti-tumor immune response, offering a promising path toward personalized cancer immunotherapy.

Citation Format: Yue Liu, Joanna Pagacz, Donald J. Wolfgeher, Stephen J. Kron. Senescent cancer cell vaccines induce cytotoxic T cell responses targeting primary tumors and disseminated tumor 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 2966.
Abstract 2979: Pancreatic cancer cells upregulate LPAR4 in response to isolation stress to create a fibronectin-rich extracellular matrix niche and promote tumor initiation
Authors: Wu Chengsheng , Rakhshandehroo Taha , Wettersten Hiromi I. , Campos Alejandro , Von Schalscha Tami , Jain Shashi , Yu Ziqi , Tan Jiali , Mose Evangeline , Childers Betzaira G. , Lowy Andrew M. , Weis Sara M. , Cheresh David A.
Published: March 2024

Tumor initiation is an inefficient process in which tumor cells must develop cell-autonomous mechanisms to survive harsh microenvironments, establish colonies, and thereby overcome “isolation stress.” We report that pancreatic cancer cells transiently upregulate lysophosphatidic acid receptor 4 (LPAR4), a G-protein coupled receptor, in response to microenvironmental stress or chemotherapy, which promotes stress tolerance, drug resistance, and tumor initiation. Even without exogenous LPA, LPAR4 drives the expression of a subset of extracellular matrix (ECM) genes via an AKT/CREB axis, including fibronectin and versican, which are established drivers of cancer stemness. The upregulation of fibronectin is indispensable for LPAR4-induced tumor initiation in vivo and anchorage-independent growth in vitro. Furthermore, the ligation of this fibronectin-containing ECM created by LPAR4-positive cells via integrins α5β1 or αvβ3 can transfer cancer stemness and stress tolerance to LPAR4-negative cells by activating Yes-associated protein 1 (YAP). Our findings reveal that in response to isolation stress, pancreatic tumor cells that upregulate LPAR4 can autonomously generate a fibronectin-enriched ECM niche and thereby initiate tumor formation.

Citation Format: Chengsheng Wu, Taha Rakhshandehroo, Hiromi I. Wettersten, Alejandro Campos, Tami Von Schalscha, Shashi Jain, Ziqi Yu, Jiali Tan, Evangeline Mose, Betzaira G. Childers, Andrew M. Lowy, Sara M. Weis, David A. Cheresh. Pancreatic cancer cells upregulate LPAR4 in response to isolation stress to create a fibronectin-rich extracellular matrix niche and promote tumor initiation [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 2979.
Abstract 3011: The loss of an orphan nuclear receptor NR2E3 augments Wnt/β-Catenin signaling via epigenetic dysregulation that links to the Sp1-β catenin-p300 interactions in hepatocellular carcinoma
Authors: Leung Yuet-Kin , Lee Sung-Gwon , Wang Jiang , Ho Shuk-Mei , Rusch Nancy , Park Chungoo , Kim Kyounghyun
Published: March 2024

Hepatocellular carcinoma (HCC) stands as the fourth leading cause of global cancer-related mortality due to late-stage detection, tumor heterogeneity, and drug resistance. The pivotal role of epigenetic factors in HCC development and progression necessitates the identification of critical epigenetic regulators. The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3), primarily associated with retinal development, has emerged as a potential tumor suppressor. Earlier studies showed that the loss of NR2E3 leads to epigenetic repression of the estrogen receptor α (ER) through the involvement of Lysine Specific histone Demethylase 1 (LSD1). NR2E3 also forms a transcriptional complex with Sp1, governing the aryl hydrocarbon receptor (AHR) expression, a crucial factor in liver xenobiotic metabolism. In vivo, NR2E3 ablation results in p53 inactivation and severe liver injuries when exposed to liver toxicants, highlighting its role in activating p53. Nonetheless, the precise tumor suppressive and epigenetic role of NR2E3 in HCC remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the Wnt/β-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice show accelerated liver tumor formation and progression accompanied by enhanced activation of the Wnt/β-catenin signaling pathway and inactivation of the p53 signaling pathway. At a cellular level, losing NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates vital genes in the Wnt/β-catenin pathway with enhanced chromatin accessibility. This event is mediated through the increased formation of active transcription complex involving Sp1, β-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. Correspondingly, treatment of p300 inhibitor C646 decreased the expression of critical genes in the Wnt/β-catenin signaling pathway. These findings demonstrate that the loss of NR2E3 promotes Wnt/β-catenin signaling activation at cellular, organismal, and clinical levels. In summary, NR2E3 is a novel tumor suppressor that maintains epigenetic homeostasis, thereby preventing activation of Wnt/β-catenin signaling that promotes HCC formation.

Citation Format: Yuet-Kin Leung, Sung-Gwon Lee, Jiang Wang, Shuk-Mei Ho, Nancy Rusch, Chungoo Park, Kyounghyun Kim. The loss of an orphan nuclear receptor NR2E3 augments Wnt/β-Catenin signaling via epigenetic dysregulation that links to the Sp1-β catenin-p300 interactions in hepatocellular 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 3011.
Abstract 3012: Characterizing the functional significance of "variant of uncertain significance" of the tumour suppressor CDH1
Authors: Wen Jasmine , Singh Ajay , Nguyen David , Meier-Ross Kaitlynn , Martin Ben , Khan Vedanta , Dhami Kiran , Chao Jesse
Published: March 2024

We aim to develop a new approach to systematically characterize the functional significance of “variant of uncertain significance (VUS),” focusing on the tumor suppressor gene CDH1. Genetic testing is a powerful clinical tool for identifying individuals at risk of developing inherited or familial cancers. If a potential cancer-causing genetic variant (mutation) is found, clinicians can begin managing the patient’s risk early by initiating surveillance or prophylactic treatment. For an aggressive form of inherited stomach cancer called hereditary diffuse gastric cancer (HDGC), the most commonly mutated gene is CDH1, which encodes the tumor suppressor E-Cadherin. However, due to insufficient clinical evidence, over 50% of all publicly reported CDH1 variants either have conflicting interpretations or cannot be classified, thus are not actionable. Consequently, almost 1 in 2 patients who undergo genetic testing for HDGC will not have a definitive test result and cannot benefit from early screening, causing strain on the healthcare system and psychological burden for the patients. To overcome this challenge, we developed a single-cell screening system to accurately classify CDH1 variants using a combination of functional assays, machine learning, and deep learning. Our hypothesis, now supported by preliminary data, is that pathogenic variants will disrupt normal E-Cadherin’s ability to control its signaling partner beta-catenin. Thus, loss-of-function (LoF) CDH1 variants would cause protein mislocalization and altered signaling which lead to abnormal proliferation, an early indicator for carcinogenesis. We express CDH1 variants in human cell lines and use multiplexed high-content imaging to visualize E-Cadherin and beta-catenin. Next, our deep learning pipeline extracts single-cell phenotypic profiles, and our classifier then classifies variants as functional or LoF. Initial analysis of prioritized variants show that our pipeline can accurately separate clinically pathogenic and benign variants based on their functional status as predicted by our pipeline. The outcomes of this project will contribute to a systematic approach to reclassify VUS.

Citation Format: Jasmine Wen, Ajay Singh, David Nguyen, Kaitlynn Meier-Ross, Ben Martin, Vedanta Khan, Kiran Dhami, Jesse Chao. Characterizing the functional significance of "variant of uncertain significance" of the tumour suppressor CDH1 [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 3012.
Abstract 3019: Dissecting in vivo functions of R-Loops in Brca1-associated DNA replication stress and mammary tumorigenesis
Authors: Chiang Huai-Chin , Qi Leilei , Hu Yanfen , Li Rong
Published: March 2024

Germ-line BRCA1 mutations are associated with a significantly increased incidence of breast cancer in women. Although BRCA1-associated breast tumors are basal-like and estrogen receptor α negative (ERα−), they originate from luminal progenitor cells. At the molecular level, BRCA1 is best known for its roles in resolution of DNA replication stress and promotion of homologous recombination (HR)-based double strand break (DSB) repair. In addition, BRCA1 is implicated in reduction of R-loops, a DNA-RNA hybrid structure and transcriptional byproduct associated with genome instability and transcriptional regulation. Our published findings suggest that BRCA1-dependent R-loop mitigation contributes to luminal cell-specific transcription and differentiation (Zhang et al, 2017, Nature Communications, 8:15908), which could in turn suppress Brca1-associated tumorigenesis. Using cell type-specific mouse genetics, we investigate a direct impact of R-loop removal on Brca1-associated mammary epithelial tumor formation. R-loop formation in mammary epithelial cells is efficiently reduced by over-expression of RNase H1, an R-loop-specific ribonuclease. R-loop removal does not affect mammary duct development or function. However, it drastically increases ɣH2AX foci in proliferating BRCA1-deficient epithelial cells without external DNA damage. This suggests a role of R-loops in attenuating elevated DNA replication stress caused by the loss of Brca1. While R-loop removal does not appear to affect the overall Brca1-associated mammary tumor incidence, it promotes cell differentiation from ERα− luminal progenitor cells to ERα+ mature luminal cells. Accordingly, unlike their counterparts, a significant percentage of Brca1-associated mammary tumors with RNase H1 overexpression tend to be ERα+. Thus, our findings provide in vivo evidence for a previously unappreciated role of R-loop dynamics on Brca1-associated DNA replication stress and tumor development in mammary epithelium.

Citation Format: Huai-Chin Chiang, Leilei Qi, Yanfen Hu, Rong Li. Dissecting in vivo functions of R-Loops in Brca1-associated DNA replication stress and mammary tumorigenesis [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 3019.
Abstract 3053: PTEN as a double-edged sword regulates EGFRL858R-induced lung cancer progression
Authors: Hung Jan-Jong
Published: March 2024

Lung cancer is the major cause of death worldwide. Activation of oncogenes or inhibition of tumor suppressors causes cancer formation. Previous studies have indicated that Pten, as a tumor suppressor, inhibits cancer formation. In this study, we studied the role of Pten in EGFRL858R-induced lung cancer in vivo. Interestingly, loss of Pten increased bronchial cell hyperplasia but decreased alveolar cell hyperplasia in EGFRL858R*Pten−/−-induced lung cancer. Syatematic analysis of gene expression by RNA-seq showed that a number of genes related to ciliogenesis were upregulated in EGFRL858R*Pten−/−-induced lung cancer and subsequently showed that bronchial ciliated cells were hyperplastic. Several critical ciliogenesis-related genes, such as mucin5a, DNAI2 and DNAI3, were found to be regulated by NR2F1. Next, NR2F1 was found to be inhibited by overexpression of Pten, indicating that Pten negatively regulates NR2F1, thereby inhibiting the expression of ciliogenesis-related genes and leading to the inhibition of bronchial cell hyperplasia during EGFRL858R-induced lung cancer progression. In addition, we also found that Pten decreased Akt phosphorylation in A549, Kras mutant, and H1299 cells but increased Akt phosphorylation in PC9, EGFRL858R, and H1299L858R cells, suggesting that Pten may function as a tumor suppressor and an oncogene in lung cancers with Kras mutation and EGFR mutation, respectively. PTEN acts as a double-edged sword that differentially regulates EGFRL858R-induced lung cancer progression in different genomic backgrounds. Understanding the Pten in lung cancer with different genetic backgrounds will be beneficial for therapy in the future.

Citation Format: Jan-Jong Hung. PTEN as a double-edged sword regulates EGFRL858R-induced lung cancer progression [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 3053.
Abstract 3056: Copper chelation modulates YTHDF2 RNA-binding protein localization and global translation, in neuronal cancers
Authors: Bell Jessica L. , Abruzzese Domenico K. , Kasiou Erin , Pham Vu Vu , Bertoldo Jean B. , Michniewicz Filip , Vittorio Orazio
Published: March 2024

Cancers are dependent on copper for growth, angiogenesis and metastasis and copper chelators are in clinical trials against breast cancer, however the mechanisms of this emerging cancer treatment are still largely unexplored. We previously demonstrated that copper chelation has efficacy in mouse models of neuroblastoma and glioma. Multiomics analyses in neuronal cancers suggested that RNA-binding proteins were deregulated by copper chelator treatment. We found that the “RNA Binding” gene set was the most significantly ranked molecular function list using differentially expressed RNAs after copper chelation treatment (GO:0003723, p-value 1.02e−32). We subsequently found that the copper chelator drug decreased global protein synthesis, MYC/MYCN expression, as well as the amount a key methylated (m6A) RNA-binding protein called YTHDF2 in glioma cells, by RNA-seq (-log2FC 0.3, p-value 0.005) and western blot. This downregulation was also clear in neuroblastoma and glioblastoma cell lines. Interestingly, copper chelation also shifted YTHDF2 protein location into the nucleus. YTHDF2 knock-out (DepMAP Chronos dependency score, -0.32) and knock-down studies (siRNA pool, 38% decrease in cell confluence) in neuroblastoma cell lines and others, indicated that YTHDF2 depletion is selective against neuronal cancer cell growth. YTHDF2 was found to be a MYCN transcriptional target. Moreover, as YTHDF2 protein also binds MYCN transcripts (the principal oncogene in neuroblastoma), and copper signaling mRNAs, it appears that copper signaling, YTHDF2 and MYCs operates in an oncogenic-axis. Ongoing studies are investigating novel YTHDF2 inhibitors and their neuronal cancer efficacy. Our work represents a significant breakthrough in drugging oncogenic post-transcriptional processes either directly, or indirectly via depleting copper.

Citation Format: Jessica L. Bell, Domenico K. Abruzzese, Erin Kasiou, Vu Vu Pham, Jean B. Bertoldo, Filip Michniewicz, Orazio Vittorio. Copper chelation modulates YTHDF2 RNA-binding protein localization and global translation, in neuronal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3056.
Abstract 3076: Unveiling the therapeutic potential of β-catenin inhibition in triple negative breast cancers: Targeting the Warburg effect
Authors: Umar Sheikh Mohammad , kahol Shruti , JR Arundhathi Dev , Kashyap Akanksha , Mathur Sandeep R. , Gogia Ajay , Deo S.V.S , Prasad Chandra
Published: March 2024

Introduction: Triple Negative Breast Cancer (TNBC) exhibits increased glycolysis, known as the Warburg effect. Recent research, including our own Nanostring nCounter studies, identify β-catenin as an oncoprotein linked to elevated glycolysis in TNBC tumors. Our current research explores the impact of β-catenin inhibitors on glycolysis in TNBC cell lines and an in vivo CDX model.

Method: We employed immunohistochemistry to assess 98 TNBCs for the presence of β-catenin, PFKP, LDH-A, and MCT1 proteins, exploring their correlation with clinicopathological factors. In in-vitro experiments using MDA-MB-231, MDA-MB-468, and 4T1 cell lines, we investigated how β-catenin inhibitors (XAV939 & Axitinib) affected aerobic glycolysis components, and TNBC cell characteristics (proliferation, migration, invasion, and stemness). For in-vivo validation, 4T1 TNBC xenografts were employed to confirm our findings.

Results: Among the 98 TNBC patients, 63 (64%) displayed cytoplasmic/or nuclear β-catenin staining. Additionally, cytoplasmic accumulation of PFKP was observed in 52/98 (53%), increased cytoplasmic LDH-A expression in 57/98 (58%), and membranous MCT-1 expression in 50/98 (51%) TNBC patients. Notably, significant positive correlations were found between nuclear/cytoplasmic β-catenin and cytoplasmic PFKP (p = 0.001) as well as membranous MCT1 (p = 0.014). Furthermore, β-catenin, PFKP, LDHA, and MCT1 proteins were overexpressed in all TNBC cell lines thereby supporting their glycolytic nature. Comparative analyses between XAV939 and Axitinib revealed that Axitinib significantly reduced various TNBC cell parameters, including migration, invasion, lactate production, colony-forming ability, and expression of aerobic glycolytic pathway proteins. In the in-vivo studies, 30mg/kg Axitinib in a female Balb/c-4T1 xenograft model resulted in a substantial reduction in tumor volume and weight.

Conclusion: Our findings show that increased levels of β-catenin play an important role in regulating aerobic glycolysis in TNBCs. Furthermore, our findings also highlight Axitinib's potential as an effective therapeutic agent for the treatment of β-catenin-positive TNBCs.

Citation Format: Sheikh Mohammad Umar, Shruti kahol, Arundhathi Dev JR, Akanksha Kashyap, Sandeep R. Mathur, Ajay Gogia, S.V.S Deo, Chandra Prasad. Unveiling the therapeutic potential of β-catenin inhibition in triple negative breast cancers: Targeting the Warburg effect [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 3076.
Abstract 3131: Novel CDH17-targeting antibody-drug conjugate exhibits anti-tumor efficacy in preclinical models of gastrointestinal cancers
Authors: Wong Po Yee , He Lin , Chow Kronos , Wong Kwan Wa , O Chui Yee , Wong Dennis , Luk John Moon , Lo Pui-Chi , Wong Kwong Fai
Published: March 2024

Antibody-drug conjugates (ADC) for oncology indications have been developed, however, only few of them are approved for the treatment of gastrointestinal (GI) cancers, which represent as a huge unmet medical need. As such, we developed a novel ADC of which monomethyl auristatin E (MMAE), an antimitotic agent, was conjugated to a cadherin-17 (CDH17)-targeting monoclonal antibody via protease-cleavable peptide valine-citrulline linker. CDH17 is highly restricted to the intestinal adherent junctions which is not accessible in healthy individuals. In contrast, it is overexpressed and becomes reachable in over half of the gastric and pancreatic cancer patients and in more than 95% of patients with colorectal cancer, making it a perfect target for ADC. Our ADC is designed to deliver MMAE specifically to CDH17-expressing tumors to exert the cytotoxic effect of MMAE on cancer cell, mitigating the undesired off-target cytotoxicity. LC/MS analysis revealed that MMAE was conjugated in a drug-to-antibody ratio of 4 with a yield of higher than 75%. ELISA showed that the binding of naked antibody and ADC to CDH17 was comparable (EC50, 0.17 nM & 0.3 nM, respectively), indicating the conjugation process did not affect antigen binding. This ADC also bound to different CDH17-expressing cell lines, including pancreatic AsPC1 and gastric AGS (EC50, 2.1 nM & 1.53 nM, respectively). By labelling the ADC with pH-sensitive fluorescent indicator, we illustrated that ADC internalization only occurred in CDH17+ but not CDH17- cells, suggesting the high specificity of the ADC. Similarly, the ADC showed selective killing on CDH17+ cells (EC50, 0.02-0.5 nM), and the data together proposed a positive correlation between ADC internalization level and its cytotoxicity (R2 = 0.4307). This supported the specificity and safety of the ADC in killing CDH17+ cancer cells only without affecting normal cells. Furthermore, a preliminary in-vivo study on subcutaneous AsPC1 xenograft model demonstrated that the ADC significantly suppressed tumor growth without causing any changes in body weight. Our ADC would potentially be a “First-in-class” ADC for the treatment of GI cancers with minimal adverse systemic toxicity. Further pharmacokinetics, safety, and other IND-enabling studies are underway.

Citation Format: Po Yee Wong, Lin He, Kronos Chow, Kwan Wa Wong, Chui Yee O, Dennis Wong, John Moon Luk, Pui-Chi Lo, Kwong Fai Wong. Novel CDH17-targeting antibody-drug conjugate exhibits anti-tumor efficacy in preclinical models of gastrointestinal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3131.