Treatment Of Pancreatic Cancer Research Articles

Abstract 6692: Intermittent fasting-remodeled gut microbiota improves anti-tumor immunity in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) has become the third leading cause of cancer-related death in the United States with high resistance to therapies, presentation at late stages and aggressive biology. Immunotherapy has revolutionized cancer therapy by offering survival benefit in many solid malignancies, however, it is still not effective in pancreatic cancer. Host factors are crucial modulators of responses to immunotherapy. The roles of gut microbiome in modulating the immune system and determining cancer outcomes have been well established. Eating patterns can alter the gut microbiota and metabolic output, both of which affect anti-tumor immune responses. Intermittent fasting (IF), a form of dietary restriction which is characterized by limited feeding with unlimited calorie consumption during a certain time window. IF has been shown to affect gut microbiota composition, modulate immunity, and metabolic processes. Despite the well-known beneficial role of fasting in pancreatic conditions, including pancreatitis and diabetes, its effect in the treatment of pancreatic cancer has not been explored. Our study found that IF reverses immunotherapy resistance in PDAC. IF can reshape gut microbiota composition and reprogram the metabolism of host. We found that IF improves anti-tumor immunity through modulating gut microbiota. Depletion of gut microbiota can abrogate the beneficial effect of IF on anti-tumor response, while fecal microbiota transplantation from mice exposed to IF can sensitize the anti-tumor effects of immunotherapy. Using 16S rRNA sequencing, metabolic profiling and transcriptomic sequencing, our findings elucidate the mechanism of IF-remodeled gut bacteria influencing metabolic molecules which drive immune cells activation. Our study suggests that IF-based interventions have potential utility for the prevention and treatment of PDAC. Citation Format: Le Li, Vidhi Chandra, Olivereen Le Roux, Rian Morgan Howell, Virginia Tahan, Nagireddy Putluri, Joseph Petrosino, Arun Sreekumar, Jay K. Kolls, James White, Florencia McAllister. Intermittent fasting-remodeled gut microbiota improves anti-tumor immunity in pancreatic 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 6692.

Abstract 1828: Development and evaluation of novel gemcitabine analog for the treatment of pancreatic cancer

Abstract Purpose: Gemcitabine acts against pancreatic cancer and a wide range of solid tumors and it is known to be rapidly deaminated or metabolized in the blood to an inactive metabolite. To increase its therapeutic levels, gemcitabine is administered at high doses causing severe side effects. To improve its metabolic stability, increase cytotoxic activity, and limit the phenomena of resistance many alternatives have emerged, such as modifying gemcitabine. The purpose of this study was to develop and characterize a novel gemcitabine analog with improved stability and enhanced anticancer activity against pancreatic cancer. Methods: A novel analog of gemcitabine (GemAGY) was designed and synthesized through chemical modification of gemcitabine hydrochloride (GemHCl) at position 4 with hydroxylamine. Gem AGY was characterized using nuclear magnetic resonance (NMR), micro-elemental analysis, and purity determined using High-Performance Liquid Chromatography (HPLC). Pancreatic cancer cell lines (MiaPaCa-2, BxPC3, and PANC-1) were treated with GemHCl and GemAGY. Cytotoxicity, cell migration, clonogenic assay, cell cycle, and apoptosis studies were performed to evaluate the effect of GemAGY against pancreatic cancer cell lines. Results: The percent purity of GemAGY was over 99.6%. GemAGY demonstrated a higher cytotoxic effect against pancreatic cancer cells with a lower half-maximal inhibitory concentration (IC50) value (2.5-fold high) compared with GemHCl. For MiaPaCa-2 cells, the IC50 value of GemAGY was found to be 1.63 ± 0.15 µm compared to GemHCl (4.0 ± 1.7 µm). GemAGY also exhibited higher cytotoxicity in PANC-1 (IC50: 1.7 ± 0.2µm) compared to GemHCl (IC50: 5.6 ±1.3 µm) and the IC50 value of GemAGY (3.2±1.1µm) in BxPC-3 cells was significantly better than GemHCl (5.5±1.0 µm). The cell cycle analysis indicated that GemAGY-treated MiaPaCa-2 cells at 1.50 µm concentration had a higher G0/G1 population (60.24%) compared to GemHCl-treated cells (55%). The cell migration studies showed that GemAGY-treated MiaPaCa-2 cells at 12.5 µm concentration significantly inhibited cell mobility towards the wound area with migrated cells found to be 65 ± 6 compared to Gem HCl (174.3 ± 4.0) (GemAGY vs GemHCl; p<0.0001). Similarly, GemAGY-treated PANC-1 cells at 12.5 µm concentration significantly inhibited cell mobility towards the wound area with (98 ± 5.1) compared to Gem HCl (254 ± 6.6). The quantitative analysis of apoptosis studies showed that GemAGY significantly induced higher apoptosis in a dose-dependent manner in MiaPaCa-2 cells compared to GemHCl as concentration increases (GemAGY vs GemHCl; p <0.0001). Conclusion: This study demonstrates that GemAGY increases the anticancer activity of gemcitabine and may have the potential to improve the chemotherapeutic efficacy of gemcitabine in the treatment of pancreatic cancer. Citation Format: Joy Okoro, Raviteja Bulusu, Esther K. Frimpong, Sherise Rodgers, Bo Han, Xue Zhu, Edward Agyare. Development and evaluation of novel gemcitabine analog for the treatment of pancreatic 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 1828.

Abstract 5261: Immunologic signatures of peripheral blood cells in patients with advanced pancreatic cancer under lenvatinib-pembrolizumab maintenance therapy

Abstract Background: The treatment of pancreatic cancer is limited by chemotherapy toxicities which impacts quality of life. This is a phase 2 clinical trial of lenvatinib and pembrolizumab as maintenance therapy in patients with advanced pancreatic cancer. We observed preclinical activity of this combination in pancreatic mouse models. We hypothesize that this combination may address unmet needs to minimize toxicities associated with standard treatments, stimulate anti-tumor T cell immunity, and improve the progression free and overall survival. Exploratory studies aim to characterize immune-related systemic changes in peripheral blood over the course of therapy and to identify global changes in expression of tumor-related genes in needle biopsy samples of liver metastatic lesions. Methods: Multiplex gene expression analysis of unsorted peripheral blood mononuclear cells (PBMC) was performed using PanCancer Immune Profiling Panel on NanoString nCounter platform. PBMC samples from pre- through week 32 of treatment were assessed for differential expression of 730 immune profiling genes defining T cell functions and associated immune categories. Results: PBMC immune profiling from 4/5 patients show a distinctive pattern of increased activation of T cells during the first 9 weeks of treatment followed by a sharp inhibition starting at weeks 9-12 after 3-4 cycles of treatment (CD3E, CD247, LCK, TBX1, TCF7, STAT4, IL2RG). Subsequent upregulation of macrophage-derived scavenger, inflammatory, and immunosuppressive gene expression patterns continued for the remainder of treatment (CD14, MSR1, MARCO, CD68, TGFB1, IL10RA). The median PFS of first 10 patients was 21.5 (9-32) weeks. Conclusions: Immunotherapy resistance may be related to rapidly developing terminal differentiation and unresponsiveness of T cells in parallel with upregulation of macrophage-derived inflammatory and immunosuppressive processes. Studies are on-going to prevent inhibition of the T-cells. Citation Format: Vincent Chung, Ferdynand Kos, Edwin Manual, Shannon Dempsey, Don J. Diamond. Immunologic signatures of peripheral blood cells in patients with advanced pancreatic cancer under lenvatinib-pembrolizumab maintenance therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5261.

Abstract 7170: Pharmacokinetic profiling of Re-Phenformin in vivo: A novel approach in pancreatic cancer therapy

Abstract Phenformin, a biguanide medication, has long been utilized in the treatment of diabetes. Recent research indicates that phenformin may also serve as an effective anticancer agent. This study introduces the synthesis and evaluation of Re tricarbonyl phenformin complex (Re-(CO)3-Phenformin, Re-Phen), as a derivative of Phenformin and novel anticancer agent for pancreatic cancer treatment. Re-Phen was synthesized, purified, and characterized through preparative HPLC, NMR, mass spectrometry, and FT-IR. Subsequent in vitro studies, utilizing the MTS assay, assessed its cytotoxicity against pancreatic cancer cell lines, including Kras* murine PDAC and MiaPaca-2 human PDAC. Notably, Re-Phen exhibited significantly higher cytotoxic effects in MiaPaca-2 cells (IC50= 0.755 mM) and Kras* cells (IC50= 0.410 mM) compared to Phenformin treatment (IC50= 4.02 mM and 2.36 mM, respectively). These results highlight Re-Phen's enhanced anticancer activity, outperforming Phenformin in potency. Further investigation into the pharmacokinetics of Re-Phen involved an in vivo study with rats intravenously administered 2 mg/kg of Re-Phenformin. Blood samples were collected at intervals (10 min to 24 h post-dose) and were analyzed by validated LC-MS/MS. The pharmacokinetic profile of Re-Phen was best described by a 2-compartment model, using Phoenix® WinNonlin (version 8.0), with a particular focus on comparing the profiles of Phenformin and Re-Phen. The study revealed that Re-Phen has a significantly extended half-life compared to Phenformin (9.13 hr vs 2.11 hr), indicating prolonged systemic retention. Additionally, Re-Phen demonstrated an increased area under the curve (AUC), suggesting greater systemic exposure at equivalent dosing (90.55 hr*ng/ml vs 7.13 hr*ng/ml). This could imply enhanced bioavailability or altered metabolic clearance of Re-Phen compared to its parent compound. The two-Compartment of Re-Phe, provide a deeper understanding of its pharmacokinetic characteristics. In conclusion, Re-Phen not only demonstrates superior anticancer efficacy in vitro but also exhibits a more favorable pharmacokinetic profile in vivo. The extended half-life and increased AUC of Re-Phen suggest the potential of offering improved therapeutic efficacy in pancreatic cancer treatment. These promising findings warrant further investigation and could position Re-Phen as a promising therapeutic agent for the pharmacological management of pancreatic cancer. Citation Format: Amir Mohammad Gholizadeh, Lu Dai, Fatima Dagher, Chiyi Xiong, Chun Li, Diana S-L Chow. Pharmacokinetic profiling of Re-Phenformin in vivo: A novel approach in pancreatic cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7170.

Optimisation Studies of Mesoporous Silica Nanoparticle as a Drug Carrier for Gemcitabine: Enhancing Therapeutic Effectiveness in Pancreatic Cancer

Pancreatic cancer, often referred to as “the silent killer”, presents with minimal or no symptoms in its early stages, leading to late detection when surgical resection is no longer the optimal treatment option. Gemcitabine (GEM), one of the leading chemotherapeutic drug for advanced stages of cancer, is a crucial treatment for pancreatic cancer. However, the low 5-year survival rate of pancreatic cancer patients highlight the limited effectiveness of current treatments. In recent years, mesoporous silica nanoparticles (MSNP) have garnered significant attention in both scholarly and pharmaceutical fields due to their unique combination of properties including stable porous structure and high loading capacities. This research aims to investigate the potential of MSNP as a carrier for anticancer drugs, specifically GEM. MSNP was successfully synthesized in the laboratory using sol-gel method with tetraethyl orthosilicate (TEOS) as silica source and cetyltrimethylammonium bromide (CTAB) as surfactant template. Comprehensive morphological and physical characterizations of the MSNP product were performed through transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, element mapping, X-ray diffractometry (XRD), and accelerated surface area porosimetry (ASAP). The results demonstrate that MSNP exhibits desirable properties for drug loading, including a stable mesoporous structure with pore size of ~ 4.94 nm, a high surface area of about 278.32 m²/g, and average particle diameter of approximately 85 nm. The effects of incubation time and initial GEM concentrations were studied to determine the optimal drug loading parameters for the MSNP vehicle. The successful loading of up to 24 µg of GEM in 1 mg of MSNP achieved in an optimized incubation time of 2 hour, validates the tremendous potential of MSNP as a potential anticancer drug carrier in pancreatic cancer treatment. These findings provide a valuable reference for future research and investigations in this promising field.

Abstract 2176: Differences in gut microbial composition alter pancreatic tumorigenesis

Abstract Pancreatic ductal adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer-related deaths by 2030, and currently has a 5-year survival rate of roughly 10%. With long-term survival rates in patients being exceedingly low, understanding what factors delineate survival is imperative. When comparing spontaneous transgenic mouse models of pancreatic cancer housed in geographically distinct vivaria, regardless of a common lineage, we observed drastically different phenotype states in the respective locations. We hypothesize that the gut microbiome results in different gene expression profiles, leading to alterations in pancreatic tumorigenesis. Using various sequencing techniques, including 16s rRNA and RNA sequencing of the gut, we identified unique signatures at these respective institutions. Subsequent fecal microbiota transplantation and single bacterial species colonization experiments were performed to evaluate the ability of microbiomes/specific microbiota to alter the rate of tumorigenesis. In addition to probing the gut microbiome, circulating metabolites from individual mice were quantified, and correlated to phenotype state. Following identification of potentially tumorigenic bacterially derived metabolites, single bacteria colonization experiments were utilized to determine the downstream effects of identified metabolites as well as the ability of directly altering the metabolic landscape to drive tumorigenesis. Additionally, murine derived pancreatic cancer cells were exposed to both identified bacteria alone or bacterially produced metabolite and analyzed by metrics such as proliferation and relative expression of transcription factors associated with cancer development in vitro. Taken together, these data demonstrate the ability of distinct gut microbiomes to directly alter the metabolic landscape in mice, thus differentially altering the progression of pancreatic lesions. By better understanding the factors that stratify survivorship, we can begin to employ clinically actionable methodologies in the treatment or prevention of pancreatic cancer. Citation Format: Rian M. Howell, Jose Enriquez Ortiz, Olivia Le Roux, Vidhi Chandra, Le Li, Pratip K. Bhattacharya, Florencia McAllister. Differences in gut microbial composition alter pancreatic 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 2176.

Abstract 3147: DXC025, a novel anti-MUC1/EGFR bispecific antibody-tubulysin conjugate with a function linker, exhibits potent anti-tumor efficacy

Abstract Antibody-drug conjugates (ADCs) have become a promised drug class in cancer therapy. Armed with three main components-an antibody, a linker molecule, and a cytotoxic agent (“payload”), plus sites of the antibody conjugation and the distribution of tumor-associate antigens, nowadays ADCs have proved the unique ability of the precision of targeted therapy, a great leap forward from traditional chemotherapeutic approaches that cause widespread effects without specificity. Both epidermal growth factor receptor (EGFR) and mucin 1 (MUC1) are tumor-associated antigens (TAA) that are co-expressed in many solid tumors, such as, colon cancer, non-small cell lung cancer (NSCLC), esophageal cancer, epidermal cancer, and pancreatic cancer. In particular, MUC1, a glycoprotein essential for the formation of the epithelial mucous barrier, is hypoglycosylated and dimerizes with EGFR, a potent oncoprotein, in transformed cells. For our anti-Muc1 ADC clinical program, for treatment of colon and pancreatic cancers, it was found out that the highly glycosylated transmembrane Muc1 had much more turning over rates on the luminal surface of epithelial cells. Here, we first designed and generated bispecific Fab/scFv antibodies targeting both MUC1 and EGFR, using the knob-into-hole technology. The addition of the affinity- and internalization-optimized anti-EGFR arm to the other single Muc1 arm was aimed to broaden tumor selectivity and to reduce on-target toxicity, for the treatment of gastrointestinal tumors in comparison to individual full IgG1-ADC, either EGFR or Muc1-ADC. Indeed, many of generated anti- MUC1/EGFR bispecific antibodies (BsAbs) showed strong binding affinity in MUC1modetateEGFRmodetate cells, in addition to both MUC1 and EGFR highly expressed cells. Internalization assays demonstrated that the BsAbs were endocytosed in tumor cells co-expressing EGFR and MUC1 more efficiently than monoclonal antibodies targeting MUC1. The selected BsAbs were subsequently conjugated with tubulysin B analogs with varieties of Tubulysin B analog payloads and function peptidyl spacer/linkers to generate bispecific ADC (DXC025) candidates. DXC025 candidates exhibited very potent cytotoxicity in vitro against epidermal cancer, lung adenocarcinoma, and pancreatic cancer cell lines with IC50 of single or tens digital pM. In in vivo cell-derived xenograft (CDX) models, DXC025 candidates demonstrated much superior efficacies of tumor growth inhibition in comparison with parental (monoclonal), either Muc1- or EGFR- ADC for the treatment of gastrointestinal tumors. These results indicated that the MUC1/EGFR-ADC (DXC025) would be a promising ADC candidate for targeted treatment of either Muc1- or EGFR-expressing gastrointestinal tumors. Citation Format: Xingyan Jiang, Junxiang Jia, Huihui Guo, Xiangfei Kong, Yongfang Xu, Sishi Ye, Yong Du, Zhicang Ye, Qikuang Cen, Lingli Zhang, Yongxiang Chen, Gaituo Chen, Lu Bai, Yunxia Zheng, Wei Zheng, Jun Zheng, Juan Wang, Wenjun Li, Yuanyuan Huang, Linyao Zhao, Yifang Xu, Mengmeng Liu, Binbin Chen, Meng Dai, Miaomiao Chen, Zhixiang Guo, Qingliang Yang, Robert Y. Zhao. DXC025, a novel anti-MUC1/EGFR bispecific antibody-tubulysin conjugate with a function linker, exhibits potent anti-tumor efficacy [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 3147.

Abstract 5957: Development of a selective, oral ATP-competitive CDK9 inhibitor, BLX-3030, for treatment of pancreatic cancer

Abstract Introduction Transcription regulators, such as cyclin-dependent kinase 9 (CDK9), have been implicated in the super-enhancer driven transcriptional control of oncogenes in multiple cancers including pancreatic cancer. CDK9 has been shown to be employed by cancer cells for the constant production of short-lived oncoproteins such as c-Myc to maintain their survival. Due to its critical role in regulating transcription in cancer cells, CDK9 has emerged as a potential therapeutic target. Here, we report the antitumor activity of a selective, oral ATP-competitive CDK9 inhibitor, BLX-3030, in preclinical models for pancreatic cancer. Experimental Procedures Fragment-based MolecuLern driven AI workflow methods were used to design a series of ATP-competitive CDK9 specific kinase inhibitors. BLX-3030 was selected as one of the most potent leads with an IC50 of 1.1 nM in a cell-free CDK9 kinase assay. A Sulforhodamine B (SRB) assay was used to evaluate the cell growth inhibitory activity of BLX-3030 in a panel of 10 pancreatic ductal adenocarcinoma (PDAC) and 2 pancreatic neuroendocrine tumor (pNET) cell lines. Western blotting was used to determine the effects of BLX-3030 treatment on c-Myc expression in cancer cells. The combination effects between BLX-3030 and standard of care regimen, gemcitabine (GEM) and nab-paclitaxel (NP), was assessed using the SRB assay. Finally, the in vivo antitumor activity of BLX-3030 alone or in combination with GEM and NP was evaluated in a mouse cell line xenograft model for pancreatic cancer. Results BLX-3030 exhibited potent cell growth inhibitory activity in the panel of pancreatic cancer cell lines with IC50 values ranging from 133.5 nM to 508.1 nM. The potency of BLX-3030 in the cell lines appears to correlate with the expression level of c-Myc in the cell lines. BLX-3030 showed similar activities in PDAC and pNET cell lines with mean IC50 values of 244.5 nM and 194.6 nM, respectively. However, treatment with BLX-3030 for 48 hours did not seem to significantly reduce c-Myc expression in PSN-1 PDAC cells. When combined with GEM and NP, BLX-3030 demonstrated mostly additive effects in PSN-1 cells. Preliminary data from the in vivo study show that BLX-3030 improves the antitumor activity of GEM and NP. Conclusion In summary, BLX-3030 potently inhibited the growth of both PDAC and pNET cells in vitro. The growth inhibitory activity of BLX-3030 in PDAC cell lines correlates with their c-Myc expression levels. BLX-3030 showed an additive effect when combined with standard of care drugs (GEM and NP) in PDAC cell lines. Overall, the novel CDK9 inhibitor, BLX-3030, demonstrated potent activity in pancreatic cancer cell line models and presents a promising preclinical lead for pancreatic cancer. (This work was supported in part by Biolexis Therapeutics and the Seena Magowitz Foundation). Citation Format: Yesenia Barrera-Millan, Zhaoliang Li, Hariprasad Vankayalapati, David J. Bearss, Daniel D. Von Hoff, Haiyong Han. Development of a selective, oral ATP-competitive CDK9 inhibitor, BLX-3030, for treatment of pancreatic 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 5957.

Abstract 592: A novel pMEK inhibitor ABM-4095 for the treatment of pancreatic cancer

Abstract The MEK-ERK pathway is often activated in tumors by mutations of upstream BRAF- or RAS-proteins. The RAS is frequently mutated in several cancers, especially in pancreatic cancer with an about 95% rate. Pancreatic cancer has the highest mortality rate with a 5-year survival rate of 8% and a median survival of 6 months. Targeted therapies have been extensively evaluated in pancreatic cancer, however, survival improvement of this aggressive disease using a targeted strategy has been minimal. The only currently approved targeted therapy is erlotinib in combination with the chemotherapy drug gemcitabine. To date, four MEK inhibitors that block RAF-activation have been approved by the FDA, but their ability to inhibit ERK signal activated by RAS-mutations is limited due to the induction of MEK phosphorylation by relief of ERK-dependent feedback inhibition of RAF. Here, we report a novel small molecule, ATP-uncompetitive, pMEK inhibitor ABM-4095 that potently prevents phosphorylation of MEK by RAF with moderate inhibition of MEK kinase activity. Most of MEK inhibitors approved by FDA or in clinical trials increase pMEK levels instead. ABM-4095 has a good cell permeability. Its anti-cancer efficacy has been demonstrated both in the in vitro cancer cell line proliferation assay and in vivo xenograft models. ABM-4095 showed a synergy effect with erlotinib in pancreatic cancer cells. In a Miapaca-2 xenograft model, ABM-4095 showed good dose-dependent tumor inhibition as a single agent or combining with the KRAS G12C inhibitor AMG-510, and tumor regressions were observed. In summary, ABM-4095 is a potent pMEK inhibitor with a high activity against the RAS-mutant pancreatic cancer in vitro and in vivo. Detailed preclinical results will be presented. Citation Format: Min Xu, Yong Hu, Lanjiao Zhao, Xiuquan Chen, Youqin Chen, Chen Yang, Jizhi Li, Chen Chen, Xiaobing Lv. A novel pMEK inhibitor ABM-4095 for the treatment of pancreatic 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 592.

Abstract 1840: MYBBP1A AMPylated by SELO to influence its function

Abstract Introduction: MYBBP1A, named Myb-binding protein 1A, is a protein that mainly locates in nucleolar and shuttles between the nucleus and cytoplasm, nuclear import may be mediated by KPNA2, however export depend partially on XPO1/CRM1. It activates or represses transcription via interactions with sequence specific DNA-binding proteins. Repression may be mediated at least in part by histone deacetylase activity (HDAC activity). Acts as a corepressor and in concert with CRY1, represses the transcription of the core circadian clock component PER2. Preferentially binds to di-methylated histone H3 'Lys-9' (H3K9me2) on the PER2 promoter. MYBBP1A overexpressed in tumor than normal and have a significantly negative correlation with patient overall survival. We aim to explore the role of MYBBP1A in PDAC progression and underlying mechanism. In our research, we find and prove the novel AMPylating enzyme SELO-AMPylate MYBBP1A inhibits PDAC progression and modified site in S1353 and further influence downstream relative RNA, such as 18s rRNA, 28S rRNA. Methods and Materials: 1. The function of MYBBP1A in tumorigenesis at the organismal and cellular levels. MYBBP1A is widely expressed in different tissues. Firstly, we explored the correlation between MYBBP1A expression level and PDAC through TCGA database and Kaplan-Meier plotter. We then established MYBBP1A gene knockout mice mating with PDX/P53K172H/KRASG12C to induced a primary PDAC model to analyze the progression of pancreatic cancer. The effect of MYBBP1A on tumor cell growth and proliferation was explored through cell proliferation analysis and a nude mouse tumor xenograft model. 2. The MYBBP1A AMPylated by SELO influence MYBBP1A function in cell proliferation was investigated at the molecular and cellular levels. AMPylation-specific antibodies were used to confirmed MYBBP1A AMPylated by SELO in both cell lysates and purified proteins through experiments such as CO-IP and WB. Stably expressed MYBBP1A WT/S1353A were constructed to verify the function in cell proliferation or migration by SELO. The signaling molecules were further explored through CO-IP and WB to identify the changed molecular by SELO-AMPylate-MYBBP1A, revealing the entire signaling pathways of AMPylation-mediated regulation of PDAC proliferation. Conclusion: We have demonstrated the function of MYBBP1A in the formation of pancreatic cancer, and further revealed SELO-AMPylate-MYBBP1A importance in the process of reversing MYBBP1A’s role, which has played a certain significance for the treatment of pancreatic cancer and the exploration of related therapeutic targets. Citation Format: Wu Li. MYBBP1A AMPylated by SELO to influence its function [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 1840.

Abstract 2895: ILRAP blockade mediates anti-fibrotic effects in pancreatic cancer-associated fibroblasts

Abstract Introduction: Pancreatic cancer (PDAC) patients have poor prognosis partly due to excessive activity of cancer-associated fibroblasts (CAFs). CAFs drive the fibrosis that causes excessive type III collagen and extracellular matrix deposition that in turn reduces drug response resulting in poor survival. In support, high levels of the type III collagen serum biomarker PRO-C3 correlates with poor survival in PDAC. TGF-β is thought to be the main driver of PRO-C3 and tumor fibrosis. Cytokines such as Interleukin 1 (IL-1) play a key role in the pancreatic tumor microenvironment and may play a role in tumor fibrosis as well. In this study, we first investigated the potential of IL-1 in activating fibroblasts to drive fibrosis and produce PRO-C3. Subsequently, we established a co-culture of pancreatic cancer cells and pancreatic CAFs to investigate the anti-fibrotic properties of nadunolimab, an antibody that blocks IL-1 signaling by targeting IL-1 Receptor Accessory Protein (IL1RAP). Nadunolimab is currently in phase I/IIa clinical development for treatment of pancreatic cancer (CANFOUR, NCT03267316). Methods: Human primary pancreatic cancer-associated fibroblasts (CAFs) were cultured in Ficoll-media (Scar-in-a-jar, SiaJ) supplemented with TGF-β, IL-1α or IL-1β. The fibrotic activity of the fibroblasts was investigated by measuring the formation of type III collagen (PRO-C3) at days 3, 6, 9 and 12. Then, pancreatic cancer cells (BxPc3) and pancreatic CAFs were cultured either alone or in a co-culture. Nadunolimab or isotype control were added at the start of these cultures and supernatants were collected after three days. The level of PRO-C3 was measured by ELISA. Results: Both IL-1α or IL-1β were equipotent to TGF-β in inducing PRO-C3 in the SiaJ monoculture, indicating that IL-1 is pro-fibrotic. In addition, when cancer cells and CAFs were co-cultured, PRO-C3 levels increased compared to single-cell cultures (1.5-6-fold). When co-cultures were treated with nadunolimab, the induction of PRO-C3 was blocked to levels similar to monocultures, whereas the isotype control had no effect on PRO-C3 levels. Conclusion: IL-1 activated fibroblasts and induced type III collagen formation (PRO-C3), suggesting that IL-1 is a driver of tumor fibrosis. In support, pancreatic tumor cells induced collagen type III formation (PRO-C3) in pancreatic CAFs and blockade of IL1RAP with nadunolimab inhibited this collagen formation. Thus, nadunolimab may have anti-fibrotic properties and PRO-C3 could potentially be used for prognostic/predictive enrichment and as a pharmacodynamic marker in future studies evaluating anti-IL-1 modalities in PDAC. Citation Format: Neel I. Nissen, Nils Hansen, Elin Jaensson Gyllenbäck, Camilla R. Millrud, Marcus Järås, David Liberg, Morten A. Karsdal, Nicholas Willumsen. ILRAP blockade mediates anti-fibrotic effects in pancreatic 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 2895.

Abstract 2904: Small molecule inhibitor targeting DDR represents a novel therapeutic strategy for the treatment of pancreatic ductal adenocarcinoma (PDAC)

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is ranked as the second leading cause of cancer-related mortality with a 5-year survival rate of merely 12%. The complexity of PDAC lies in its intrinsic resistance to treatment, attributable to the desmoplastic tumor microenvironment, characterized by an abundance of tumor-promoting extracellular matrix (ECM) and stromal cells. We hypothesize that Discoidin Domain Receptors (DDR), members of the receptor tyrosine kinase family known for their affinity to fibrillar collagens within the ECM, play an important role in promoting PDAC growth and progression. While several drugs targeting DDR proteins have been developed, no inhibitors to DDR proteins are specific or approved for PDAC treatment, thus necessitating the development of novel therapeutic interventions. Methods. A comprehensive high-throughput screening approach employing small molecule inhibitors was executed to identify authentic inhibitors targeting DDR. Subsequently, a rigorous evaluation of specificity of these small molecules was conducted through structural activity relationship (SAR) analyses and reference-based assessments. The efficacy of candidate inhibitors was assessed through functional assays, while mechanistic insights were gleaned using a multifaceted approach, including RNA-seq, real-time PCR, western blot analysis, in vivo experimentation, and Phospho-Receptor Tyrosine Kinase (RTK) profiling to discern any unintended off-target effects. Results: Using an unbiased screening approach, we identified 13 inhibitors that specifically target DDR. SAR studies and cellular thermal shift assay validated CIDD-0108633 (8633) as a bona fide DDR2 inhibitor. Functional assays and RNA-seq analyses demonstrated 8633's capacity to inhibit PDAC growth, metastatic potential, and expression of DNA replication, cell-cycle, and DNA damage repair genes. Combination therapy of 8633 with gemcitabine synergistically reduced PDAC cell viability and metastatic potential. Mechanistic studies revealed the role of ABC transporters in mediating gemcitabine resistance. RTK profiling shows moderate kinase selectivity. In vivo studies affirmed its antitumor effects. Conclusions: The results indicate that the selective inhibition of DDR with small molecule inhibitors suppresses PDAC cell growth and progression, implying that DDR inhibitors have the potential to be developed as safe and efficacious therapeutics for the treatment of pancreatic cancers. Citation Format: Trong Phat Do, Jack Prochnau, Prabhakar Pitta Venkata, Sajid Khan, Santosh Timilsina, Deepika Singh, Daisy Medina, Radhika Amaradhi, Daohong Zhou, Matthew Hart, Stanton McHardy, Manjeet Rao. Small molecule inhibitor targeting DDR represents a novel therapeutic strategy for the treatment of pancreatic ductal adenocarcinoma (PDAC) [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 2904.

Abstract 3081: Targeting lipid kinases to enhance autophagy inhibition for the treatment of pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is characterized as the most KRAS-addicted cancer type, with KRAS mutations found in >95% of cases. Mutant KRAS relies on dysregulated metabolism to support growth. One dysregulated pathway upregulated in PDAC is autophagy, a lysosome-mediated process that degrades proteins and organelles to supply macromolecules for growth. Our lab and others have shown that inhibition of KRAS or the mitogen activated protein kinase (MAPK) components, MEK or ERK, further increases PDAC dependency on autophagy as a resistance mechanism. Cotreatment with ERK MAPK inhibitors and the autophagy inhibitor chloroquine (CQ) decreased autophagic flux, inhibited proliferation, and induced apoptosis in PDAC cells. CQ is the only FDA-approved autophagy inhibitor, and it demonstrates low potency in vivo, motivating our studies to identify strategies to improve autophagy inhibition in PDAC. We utilized a CRISPR-Cas9 loss-of-function screen to identify sensitizers to CQ in PDAC and identified 25 autophagy-related targets. We hypothesize that targeting the autophagy pathway at multiple nodes will increase the efficacy of CQ treatment in PDAC. To validate hits identified in the CRISPR-Cas9 screen, I designed an siRNA array that contained three distinct oligos for each target. I quantified changes in proliferation in a panel of four PDAC cell lines after siRNA-mediated suppression of the target genes following 3- or 6-day time points. I hypothesized that targets identified to be non-essential on their own would allow for potential synthetic lethality with CQ. To test this, I performed a 3-day knockdown followed by 3-day exposure to a dose response of CQ. I found that suppression of lipid kinases PIP4K2A, PIP4K2C, or PIK3C3 shift the dose response to CQ in a panel of PDAC lines. This indicates that loss of those targets sensitizes PDAC cells to CQ treatment. Furthermore, we found that pharmacological inhibition of VPS34, the lipid kinase encoded by PIK3C3 by the ATP-competitive inhibitor SAR-405 synergizes with CQ. My future studies will be focused on validating other targets identified in the loss-of-function CRISPR-Cas9 screen. I will measure changes in autophagic flux and apoptosis due to the loss of validated targets. The long-term goal of this project is to enhance the translatability of autophagy inhibition for patient care through identifying combinational approaches to improve CQ response in PDAC. Citation Format: Elyse G. Schechter, Jonathan M. DeLiberty, Clint A. Stalnecker, Kirsten L. Bryant. Targeting lipid kinases to enhance autophagy inhibition for the treatment of pancreatic 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 3081.

Abstract 2903: CTHRC1 induces PSCs (pancreatic stellate cells) into myCAFs (myofibroblast-like cancer-associated fibroblasts)

Abstract Collagen triple helix repeat containing-1 (CTHRC1) is a secreted protein that contributes to the progression of various cancers, including pancreatic cancer. The higher expression of CTHRC1 in tumor tissues is associated with poorer survival outcomes. However, its specific roles in tumor extracellular matrix (ECM) remodeling remain unclear. Our study aims to investigate the influences of CTHRC1 on pancreatic stellate cells (PSCs), a main source of ECM production in pancreatic cancer. The analyses of the publicly available pancreatic cancer patient data revealed that CTHRC1 is mainly expressed in cancer stroma and highly correlated with ECM-related genes. An in vitro study showed that more than 40% of these genes can be upregulated by CTHRC1. CTHRC1 specifically activated PSC into myofibroblast-like cancer-associated fibroblasts (myCAFs), which are characterized by a significantly upregulated POSTN gene expression. Periostin (coded by the POSTN gene) has a central role in the CTHRC1-PSCs-cancer metastasis axis. Furthermore, CTHRC1 promoted pancreatic cancer cell proliferation through PSC activation to a greater extent than via direct stimulation. Proof-of-concept experiments showed that the long-term (4-week) inhibition of CTHRC1 led to significant tumor suppression and ECM reduction, and also resulted in an unexpected shift in the CAF subtype from myCAFs to inflammatory CAFs (iCAFs). PSC activation was demonstrated to be the key molecular mechanism responsible for the tumor-promoting effects of CTHRC1, and CTHRC1 has a critical role in CAF subtype differentiation and tumor microenvironment (TME) remodeling. The inhibition of CTHRC1 as a therapeutic strategy for the treatment of pancreatic cancer warrants further investigation. Citation Format: Jin Gyeong Lee, Min Kyung Kang, Fen Jiang, Kyoungjin Ryu, Juwon Kim, Yun-Yong Park, Sang Seok Koh. CTHRC1 induces PSCs (pancreatic stellate cells) into myCAFs (myofibroblast-like 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 2903.

Abstract 1823: In vitro evaluation of novel pyrimidine nucleosides for the treatment of pancreatic cancer

Abstract The purpose of the study is to synthesize and characterize novel 5-FU analogs (AGY1 and AGY2) and investigate their anticancer activity against pancreatic cancer cell lines. Methods: 5-FU derivatives were synthesized and characterized using Nuclear magnetic resonance (NMR), high-performance liquid chromatography (HPLC), and elemental analysis to determine the presence of new bond formation and the purity of the derivatives or analogs. 2D cell viability, 3D models, cell migration, and cell cycle studies were performed on MiaPaCa-2 (MP-2) cells and PANC-1 cells. Apoptosis was performed on PANC-1 cells by staining with Acridine Orange and Ethidium Bromide. The metabolic stability of the analogs was determined by using human liver microsomes. PARP, p53, and BAX expressions in PANC-1 were determined by Western Blot. Results: NMR data showed the conjugation of alkyl and tetrahydrofuran groups to the 5-FU ring confirming the formation of AGY1 and AGY2. The elemental analysis of AGY1 and AGY2 showed 99.6% and 99.5 % purity respectively. The IC50 value of the AGY1 against 2D MP-2 was found to be 12.2 ± 1 µM, while the IC50 value of AGY2 was determined to be 2.9 ± 0.2 µM. Both AGY1 and AGY2 anticancer activities were significantly higher than 5-FU (18.5 ± 1.1 µM). However, AGY2 was more effective compared to AGY1. A similar trend was observed for AGY2 analog where the IC50 value for treated 2D PANC-1 was 3.1 ± 0.29 µM and demonstrated a higher anticancer activity compared to AGY1 (6.4 ± 0.38 µM) or 5-FU (7.5 ± 1.1 µM). For cell migration studies, AGY2 (43 ± 5.5) exposed MP-2 cells showed significant arrest towards the wound gap compared to AGY1 (74 ± 18.5) and 5-FU (86 ± 15.6). A similar result of cell migration arrests AGY2 was observed in PANC-1 treated-AGY1, AGY2, and 5-FU. Organoid and spheroid models demonstrated high and comparable anticancer activity of AGY1 and AGY2 compared to 5-FU treated organoid and spheroid models. The cell-cycle analysis showed that AGY2-treated MP-2 cells at 1μΜ concentration showed a higher G1 population arrest (64.25%) compared to AGY1 (54.2%) and 5-FU (55.75%). Similarly, in PANC-1 cells, AGY2 at 1μΜ concentration showed a higher S-phase arrest (53.86%) compared to AGY1 (50.76%) and 5-FU (36.14%). Metabolic stability data showed higher stability of AGY2 (95% intact) compared to AGY1 (85% intact) compared to 5-FU (55% intact) after 2 hour of human liver microsomal incubation. The expressions of p53 and BAX proteins in PANC-1 cells were significantly upregulated and PARP was downregulated at higher concentration when treated with AGY1 and AGY2 compared to 5-FU. Conclusion: We demonstrate that AGY2 showed more promising anticancer activity compared to AGY1 and 5-FU against pancreatic cancer cells. AGY2 has the potential to improve 5-FU’s metabolic stability and enhance its therapeutic efficacy. Citation Format: Raviteja Bulusu, Joy Okoro, Esther Frimpong, Bo Han, Sherise Rogers, Xue Zhu, Edward Agyare. In vitro evaluation of novel pyrimidine nucleosides for the treatment of pancreatic 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 1823.

Abstract 5742: Therapeutic efficacy of CA102N in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a challenging cancer to treat due to its aggressive nature and late-stage diagnosis. Considering the lack of effective therapies, there is an urgent need to develop new and effective therapeutics to improve the prognosis of patients. CA102N is a carrier-mediated novel anticancer product where hyaluronic acid is conjugated to Nimesulide-NH2. CA102N is currently under development for the treatment of solid tumors, including colorectal cancer. CA102N was safe and well tolerated in the first-in-human trial in patients with locally advanced or metastatic solid tumors. In the present study, the in vitro anticancer activity of CA102N was investigated in K-ras mutant PANC-1 pancreatic cancer cells. The antitumor efficacy was also tested in vivo in the PANC-1 mice model. Results demonstrated that CA102N inhibits cell growth, cell migration, angiogenesis, and cell proliferation in both K-ras mutant PANC-1 pancreatic cancer cells or tumors. Administration of CA102N in PANC-1 xenografts resulted in a dose-dependent and statistically significant decrease in tumor growth at 9.8 mg/kg and 14.7 mg/kg Nim equivalents, respectively, compared to the vehicle control group. A significant decrease (80%) in liver metastasis was also noted in the PANC-1 orthotopic mice model at 19.6 mg/kg Nim equivalents dose level. Mechanistically, CA102N was found to suppress the PI3k/Akt/mTOR and Raf/MEK/ERK signaling pathways, in addition to reducing the expressions of the N6-methyladenosine (m6A) reader and writer proteins, OCT3/4 transcription factor and RAS levels in vivo. CA102N also modified the tumor stroma and improved drug permeability in vivo. Based on this compelling data, CA102N shows promise as a potential treatment for pancreatic cancer. Combination therapies and regimens are currently being explored in in vivo models as a strategy for clinical development. Citation Format: Louis Lin, Shuling Tu, Eskouhie Tchaparian. Therapeutic efficacy of CA102N in pancreatic 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 5742.

Abstract 3322: Sigma-2-Erastin inhibits PC tumor growth through lipid ROS-DUSP6-MAPK signaling

Abstract Introduction: Pancreatic cancer (PC) is a malignancy with poor prognosis and high mortality with a very low 5-year survival rate. Currently, apoptosis and autophagy are the central mechanisms of programmed cell death (PCD) that maintain cellular homeostasis and regulate cell fate. With the recent emergence of ‘ferroptosis’ as a new type of PCD and its close association with the pathophysiological processes of many diseases including tumors, it is viewed as a potential mechanism to improve systemic treatment of PC. Considering the opportunity to regulate both apoptosis and ferroptosis by a single agent, our group has developed a cancer-targeted small molecule consisting of a sigma-2 ligand (a known apoptotic inducer) delivery moiety linked to an inhibitor of the cystine importer xCT (dm-Erastin, a known ferroptotic inducer) and named it as Sigma-2-Erastin (S2E) or ACXT-3102. The study presented here is aimed at determining the efficacy of ACXT-3102 in PC and defining its underlying mechanism of action. Methods: Using in vitro and in vivo tumor xenograft models of human PC, we determined the effects of ACXT-3102 treatments in regulating PCD of PC cells and defined the signaling pathway involved in mediating the effects. Results: As assessed by TitreGlo assays, we observed dose-dependent inhibition of PC cell (BxPC-3, AsPC-1 & PANC-1) viability. Following the WES-analysis of signaling proteins, we observed that ACXT-3102 induces PC cell death by combinatorial regulation of apoptotic and ferroptotic PCD via lipid ROS-DUSP6-MAPK/ERK-mediated signaling pathway. Interestingly, the results of this study demonstrated a hyperactivation of MAPK/ERK signaling by increased phosphorylation instead of inhibition involved in inducting apoptotic cell death as represented by significant increases in expression of cleaved Capase-3/7 and PARP. In addition, ACXT-3102 treatments deceased GPX4 expression along with an increase in lipid ROS production as key markers of inducing ferroptotic cell death. Results from the murine model of human tumor xenografts using AsPC-1 cells further demonstrated significant decreases in tumor volume and increases in survival proportions in ACXT-3102-treated mice. Conclusions: ACXT-3102, an orally administered conjugate of sigma-2 ligand and Erastin induces PCD of human PC by uniquely regulating apoptosis and ferroptosis together. Therefore, ACXT-3102 offers a novel and improved therapeutic strategy for treating patients of fatal human carcinomas, especially those, which are difficult to diagnose at an early stage. Citation Format: Kumar S. Bishnupuri, Kenneth F. Newcomer, Qingqing Gong, Li Ye, Suwanna Vangveravong, Rony Takchi, Bradley T. Keller, Dirk M. Spitzer, William G. Hawkins. Sigma-2-Erastin inhibits PC tumor growth through lipid ROS-DUSP6-MAPK signaling [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 3322.

Abstract 7125: Inhibition of IDH1 impairs homologous recombination and induces sensitivity to PARP inhibitor in pancreatic cancer

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer-related deaths in the United States. While Poly (ADP-ribose) polymerase (PARP) inhibitors hold promise in treating PDAC with Homologous Recombination Deficiency (HRD). However, HRD occurs in only 10% of cases, leaving 90% with intact Homologous Recombination Proficiency (HRP). Our research highlights the key role of wild-type isocitrate dehydrogenase 1 (IDH1) in maintaining cellular function. We found that inhibiting IDH1 increases DNA damage, suppressing the DNA repair pathway crucial for genomic integrity. This makes cancer cells susceptible to PARP inhibitors, offering a new PDAC treatment approach. Methods: The effect of IDH1 inhibition (Ivosidenib) combined with PARP inhibition (Olaparib) on in vitro growth inhibition were assessed through Trypan blue and PicoGreen in drug combination assays. Additionally, we investigated the molecular mechanism underlying the synergistic effects of drug combination. To further evaluate the therapeutic potential of IDH1 inhibition in combination with PARP inhibitors, we examined tumor growth in xenograft models of PDAC in athymic nude mice. Results: Our data report that, mechanistically, IDH1 inhibition decreased expression of HR DNA repair pathway molecules, such as BRCA1 and BRCA2, and leading to decreased HR repair efficiency in pancreatic cancer cells. Short-term cell viability data demonstrated that targeting IDH1 with ivosidenib when combined with DNA-damaging agent (Olaparib) had a synergistic effect in HRP cell lines (MiaPaCa-2 and Panc-1) with a positive synergy score and Bliss score greater than 1. Additionally, we assessed long-term cell survival using colony formation assays, which yielded a dramatic reduction in cell survival for both Panc1 and MiaPaCa-2 cells when olaparib was combined with ivosidenib, as compared to single-agent controls. Consequently, this reduction increased the levels of apoptosis induced by olaparib. Furthermore, we discovered that these two compounds complemented each other in DNA damage response, leading to an increase in the DNA damage biomarker γ-H2AX. In vivo studies using xenograft models demonstrated that the combination of ivosidenib and olaparib synergistically enhanced anti-tumor activity as compared to either single-agent used alone. Conclusion: Our data provides insights into the mechanisms underlying the susceptibility of PDAC tumor growth to a dual treatment approach involving an IDH1 inhibitor and a PARP inhibitor, particularly in the context of HRP cancer. This highlights the promise of precision medicine for pancreatic cancer treatment, though further pre-clinical studies are needed for validation and refinement. Citation Format: Mehrdad Zarei, Omid Hajihassani, Hallie J. Graor, Alexander W. Loftus, Soubhi Tahhan, Faith Nakazzi, Parnian Naji, Luke D. Rothermel, Jonothan R. Brody, Jordan M. Winter. Inhibition of IDH1 impairs homologous recombination and induces sensitivity to PARP inhibitor in pancreatic 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 7125.

Abstract 5747: Microwave responsive thermosensitive lipid nanoparticles for spatiotemporal delivery of chemotherapeutics

Abstract Pancreatic cancer is a highly lethal malignancy with an urge for the exploration of novel treatments. One promising approach is microwaved-induced hyperthermia, which has shown great antitumor and synergistic effects when combined with other therapies. The application of microwaves produces heat by dielectric hysteresis which depends on the dielectric properties of molecules. Ionic liquids (ILs) are compounds composed of ions with <100 °C melting point and have strong dielectric properties. In short, we propose the creation of microwave-sensitive nanoparticles using IL, enabling precise hyperthermia induction with low-powered microwaves in localized areas. To achieve this, we stabilize a core composed of 1-butyl-methylimidazolium bromide or 1-butyl-3-methylimidazolium hexafluorophosphate using Span 80, Tween 20, and Triton-X as surfactants, along with phosphatidylcholine lipids as “cosurfactants”. Employing a double emulsion procedure for fabrication, nanoparticles are characterized using dynamic light scattering, Fourier-transform infrared spectroscopy, and transmission electron microscopy. Furthermore, we assess microwave sensitivity by comparing thermal changes between liposomes loaded with 120 mM and 250 mM NaCl solutions. Subsequently, we evaluate biocompatibility and heat effects by incubating IL nanoparticles with BXPC3 and KPC cells, monitoring cell viability through MTT assays. We aim to confine the ILs within the nanoparticle core rather than incorporating them into the membrane. We anticipate increased microwave sensitivity, translating to reduced off-target effects and enhanced precision in hyperthermia treatment. This research holds promise for improving the therapeutic outcomes of pancreatic cancer treatment. Citation Format: Cesar B. Aparicio-Lopez. Microwave responsive thermosensitive lipid nanoparticles for spatiotemporal delivery of chemotherapeutics [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 5747.

Abstract 477: Tumor treating fields (TTFields) targeted self assembling nanoparticles for pancreatic cancer treatment: In vitro and in vivo assessment

Abstract Tumor Treating Fields (TTFields) is a novel, non-invasive and safe treatment modality, which is prescribed to be used in conjunction with classical anticancer chemotherapeutic drugs. TTFields when used alone are safe, but their use in combination with classical chemotherapy continues to offer drug related adverse reactions which ultimately impacts the patient compliance. To address this challenge, we earlier reported meticulously optimized self-assembling cationic-anionic polymer nanoparticles (S-CAP NPs) with average particle size of about 200 nM, encapsulation efficiency of 55-65 % and sustained drug release over 60 h. We also reported that, TTFields were capable of destabilizing the S-CAP NPs leading to targeted drug release. The results were also corroborated with in vitro cytotoxicity and colony formation studies in presence of TTFields using multiple pancreatic cancer cell lines. After establishing the proof-of-concept, the objective was to assess the in vitro cellular uptake of S-CAP NPs. For this, fluorescent dye loaded S-CAP NPs were developed and subjected to cellular uptake analysis. The in vitro cellular uptake studies confirmed the enhanced uptake of S-Cap NPs by passive diffusion in the pancreatic cancer cell lines compared to normal pancreatic epithelial cell line. The studies corroborated preferential cellular uptake of S-Cap NPs by the pancreatic tumor. Among all the formulations, the chitosan- bovine serum albumin S-CAP NPs was most optimum and was used for in vivo safety studies. For this, in vivo acute and repeated dose 28-day toxicity of the optimum placebo S-CAP NPs was conducted in Sprague Dawley rats (Western University of Health Sciences Protocol #R20IACUC031) and OECD guidelines. The in vivo studies showed a LD50 value above 2000 mg/kg and NOAEL value of 1000 mg/kg. These high doses safety of S-CAP NPs confirmed the potential of this approach for future preclinical efficacy studies followed by clinical translation. Lastly, the in vitro stability studies were conducted as per the ICH guidelines for a period of 36 months and the formulations were concluded to be stable. The tumor targeting potential, in vivo safety and stability of S-CAP NPs, establish their translational potential for TTFields triggered targeted drug release in cancer treatment. This approach will not only reduce the adverse effect associated with combination of TTFields and chemotherapy but can also be explored as a platform technology for management of other cancers. This study is supported by AACR-Novocure tumor treating fields research fellowship. Citation Format: Preshita Prafulla Desai, Sunil Prabhu. Tumor treating fields (TTFields) targeted self assembling nanoparticles for pancreatic cancer treatment: In vitro and in vivo assessment [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 477.