Pancreatic Tumor Cells Research Articles

CD8 + T-Cell-Related Genes: Deciphering Their Role in the Pancreatic Adenocarcinoma TME and Their Effect on Prognosis.

Because of the unique tumor microenvironment (TME), immunotherapy and targeted therapies have shown limited efficacy in treating pancreatic adenocarcinoma (PAAD). CD8 + T cells play crucial roles in regulating the TME in PAAD; therefore, exploring the function of CD8 + T-cell-related genes (CD8RGs) in PAAD has high potential clinical value and could provide a comprehensive understanding of the microenvironment of PAAD. We employed the weighted gene coexpression network analysis and CIBERSORT algorithms to assess PAAD transcriptome data from The Cancer Genome Atlas (TCGA) dataset and identify modules strongly associated with CD8 + T cell infiltration. Using least absolute shrinkage and selection operator regression analysis and Kaplan-Meier curves, we developed a prognostic risk score model for patients with PAAD. We validated this model using single-cell and transcriptome datasets obtained from the Gene Expression Omnibus (GEO). We also examined the correlations between the risk score and factors such as the TME, clinical characteristics, and tumor mutation burden (TMB). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed on differentially expressed genes between the high- and low-risk groups. In addition, the Tumor Immune Dysfunction and Exclusion website and "pRRophetic" R package were used to predict response to immunotherapy and chemotherapy in the high- and low-risk groups, respectively. Finally, we analyzed the expressions of hub genes at the cellular level with quantitative real-time PCR. A risk model based on five CD8RGs was established and validated using TCGA and GEO datasets. The low-risk group exhibited significantly longer overall and progression-free survival. A positive correlation between the TMB and the risk score was observed. The TME analysis revealed a significant correlation between the risk score and immune function, as well as immune checkpoints. The expression of hub genes was significantly correlated with the infiltration level of CD8 + T cells. The high-risk group responded better to immunotherapy, paclitaxel, cisplatin, mitomycin C, afatinib (BIBW2992), and gefitinib. In contrast, the low-risk group showed higher sensitivity to sunitinib, MK.2206, palbociclib (PD.0332991), and axitinib. Compared with that in normal pancreatic epithelial cells, the expression levels of BCL11A, PHOSPHO1, and GNG7 were significantly decreased, while those of KLK11 and VCAM1 were significantly increased in pancreatic tumor cells. CD8RGs play an important role in regulating the TME of PAAD. Five hub genes-BCL11A, KLK11, GNG7, PHOSPHO1, and VCAM1-are closely associated with the prognosis of PAAD patients, providing new references for the exploration of biomarkers. Furthermore, our findings offer novel insights for clinical decision-making.

Soluble galectin-4 in colorectal cancer is associated with tumor progression, but is not a predictor of the disease outcome

Background: Galectin-4 is a member of β-galactoside-binding protein family, which is mainly expressed in gastrointestinal epithelial cells and also secreted into the extracellular environment. Studies have shown that galectin-4 is involved in the regulation of proliferation and metastasis of gastric and pancreatic cancer tumor cells. The results of studies on the clinical significance of galectin-4 in colorectal cancer (CRC) are ambiguous: some studies showed its increased expression, associated with aggressive course and unfavorable prognosis, while others showed its decrease. Aim: To analyze the clinical significance of the soluble form of galectin-4 in CRC. Methods: We retrospectively analyzed the medical records of 130 patients (mean age, 61 year) with a verified diagnosis of CRC, who had been examined and treated from 2016 to 2022. Galectin-4 levels were measured in serum obtained by a standard method before the start of specific treatment, by the enzyme-linked immunosorbent assay (ELISA). The control group consisted of 30 healthy donors (mean age, 53 years). Results: The median concentration of galectin-4 in the CRC patients was higher than in the control group (531.9 [350.6–1380] pg/mL vs. 330.1 [173.0–566.4] pg/mL, p = 0.0004). The ROC analysis demonstrated maximum sensitivity and specificity of the test (66% and 67%, respectively) at a threshold value of 426.3 pg/mL (area under the curve 0.706 with 95% confidence interval 0.594–0.817; p = 0.0005). The galectin-4 levels were higher at advanced stages of the disease (p = 0.002) and in the presence of distant metastases (p 0.0001). Cox regression analysis showed that tumor size and distant metastases were independent prognostic factors (hazard ratio (HR) = 3.87; p = 0.0439; HR = 720.4; p = 0.0062, respectively) associated with decreased survival. Galectin-4 is not a prognostic marker of CRC (HR = 2.434; p = 0.079). Conclusion: The amounts of the soluble galectin-4 are associated with tumor progression, indicating a possible tumor-promoting function of this protein. However, its diagnostic value remains limited, as the method of serum galectin-4 determination has shown insufficient sensitivity and specificity for its routine use for the diagnosis of CRC. According to the results of univariate and multivariate analyses, serum galectin-4 is not a significant prognostic marker of CRC.

Methyltransferase-like 14 promotes the tumorigenesis and proliferation of pancreatic cancer cells through myc proto-oncogene signaling pathway

Objective: Pancreatic cancer is characterized by low survival rate and rapid deterioration. Methyltransferase-like 14 (METTL14), as N6-methyladenosine (m6A) methyltransferase, is closely related to tumor progression. The purpose of this study is to look into how METTL14 affects pancreatic cancer tumorigenesis, cell division, and apoptosis. Material and Methods: We examined and contrasted the levels of METTL14 protein and messenger RNA expression in human pancreatic ductal cells and human pancreatic cancer cells. After silencing or upregulating METTL14, the proliferative ability, migration ability, and cell apoptosis of pancreatic tumor cells was detected by colony-forming assay, wound scratch healing assay, cell counting kit 8 assay, and terminal deoxynucleotidyl transferasemediated 2’-deoxyuridine 5’-triphosphate-biotin nick end labeling assay. Following the use of c-Myc inhibitor (10058-F4), western blot analysis was carried out to investigate the key factor expression and c-Myc signaling pathway activation status. Results: METTL14 was preferentially expressed in human pancreatic cancer cells PANC-1 and SW1990 than in human normal pancreatic duct cells human pancreatic nestin-expressing cells (HPNE) (P < 0.001). Overexpression of METTL14 increased the tumorigenic and proliferative ability of pancreatic cancer cells. Overexpression of METTL14 decreased apoptosis rate. Western blot assay showed that nucleus b-catenin increased when METTL14 was overexpressed, and nucleus b-catenin decreased when METTL14 was silenced in PANC-1 cell (P < 0.01). The protein expression of other key factors, such as c-Myc, matrix metalloproteinase (MMP)-9, and MMP-2, were also affected. The use of c-Myc inhibitor (10058-F4) on the basis of OE-METTL14 reversed the effect of the overexpression of METTL14 on promoting the tumorigenesis and cell proliferation of pancreatic cancer cell lines PANC-1 and SW1990. Conclusion: METTL14 promoted the tumorigenesis and proliferation of pancreatic cancer cells by the c-Myc signaling pathway.

Abstract B002: Dynamic response and evolving adaptation of pancreatic cancer cells to the prolonged acidic pH microenvironment

Abstract Solid tumor cells are often immersed in an acidic microenvironment. While many previous studies have investigated the short-term effects of extracellular acidity on tumor cells, little is known about how they adapt to the prolonged acidic microenvironmental stress and then advance to more aggressive stages. By challenging pancreatic tumor cells as an example with continuously and gradually acidified extracellular pH, a variety of cellular characteristics including phenotypic regulation, proliferation rates, autophagic control, metabolic plasticity and metastatic potentials were identified. More detailed evidence regarding the mitochondrial network dynamics and mechanistic control of pancreatic tumor cells in response to the extracellular acidosis will be presented at this conference to emphasize the critical effects of this stress factor as a selection force for tumor adaptation and progression. These findings not only highlight the importance of dynamic response and evolving adaptation of solid tumor cells to the chronic microenvironmental acidity, but also the potential of targeting the 'acid-mediated tumor malignancy' for anticancer therapy. Citation Format: Wun-Shaing Wayne Chang. Dynamic response and evolving adaptation of pancreatic cancer cells to the prolonged acidic pH microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B002.

Abstract A022: Disrupting redox homeostasis initiates anti-tumor immune responses in pancreatic cancer

Abstract Although immune therapy has made impressive progress in cancer treatment, pancreatic ductal adenocarcinoma (PDAC) remains an exception, likely due to its immunosuppressive tumor microenvironment that prevents immune responses against the tumor. Our current work aims to reactivate the suppressive immune infiltrate using radiation therapy and oxidative stress to potentiate antitumor immune responses in PDAC. Our lab previously found that PDAC cells are dependent on the antioxidant peroxiredoxin-4 (PRDX4) expression. PRDX4 prevents excessive levels of reactive oxygen species in cells and while high PRDX4 expression is associated with a more aggressive disease, it is dispensable in normal tissue. As such, disrupting redox homeostasis by inhibiting PRDX4 represents a targetable vulnerability in cancer cells. To investigate the radio-sensitizing potential of PRDX4, we knocked-down (KD) PRDX4 in human pancreatic tumor cells as well as in mouse cancer cells obtained from the spontaneous KPC model (driven by the KRas and P53 mutations), in combination with radiation. Presence and quantification of DNA damage were performed by immunofluorescence, and impaired cell survival was analyzed by clonogenic assays. Changes in immune secretion were assessed by RT-qPCR and Elisa and in vitro macrophage phenotyping was performed upon exposure to tumor cell conditioned media. Our data so far show an accumulation of cytosolic DNA upon PRDX4 KD in PDAC cells, with the presence of micronuclei as well as less aggregated DNA. Interestingly, targeting PRDX4 before radiation amplifies the release of radiation-induced cytosolic DNA while significantly decreasing cell growth and survival, compared to radiation alone. Cytosolic DNA has been shown to trigger innate immune signaling in tumor cells. Consistently, PRDX4 loss induces the upregulation of many pro-inflammatory genes, including CCL5, CCL20, and CXCL10, in a STING-dependent manner. Combining PRDX4 KD with radiation leads to a higher gene upregulation of these immune stimulatory chemokines, as well as an increased protein secretion within tumor cell media. These findings support an amplified immunomodulatory effect of radiation when combined with PRDX4 loss in PDAC cells. To assess whether targeting PRDX4 can remodel the tumor microenvironment, we applied tumor conditioned media from cancer cells on isolated naive mouse CD45+/CD11c+/F4/80+ macrophages. Media from cells treated with PRDX4 KD + radiation strongly increased the migration ability of macrophages while modulating the expression of a subset of chemokine-encoding genes in immune cells. Using the spontaneous KPC model depleted for PRDX4, along with syngeneic orthotopic models, we are now aiming to confirm this radio-sensitizing and immune-modulatory potential of PRDX4 in vivo. The aggressiveness of PDAC requires research towards novel treatment strategies and our data strongly support evidence for targeting cancer metabolism, particularly antioxidant systems, in synergy with existing cancer therapies, like radiation and immune therapy. Citation Format: Lucie Malbeteau, Emily Poulton, Vishal Pandya, Marianne Koritzinsky. Disrupting redox homeostasis initiates anti-tumor immune responses in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A022.

Phase I Study of Adjuvant Allogeneic GM-CSF-Transduced Pancreatic Tumor Cell Vaccine, Low Dose Cyclophosphamide, and SBRT followed by FFX in High-Risk Resected Pancreatic Ductal Adenocarcinoma

PurposeLocal and distant progression remain common following resection of resectable pancreatic ductal adenocarcinoma (PDAC) despite adjuvant multiagent chemotherapy. We report a prospective institutional phase I trial incorporating adjuvant GVAX vaccine, low-dose cyclophosphamide (Cy) and SBRT followed by FOLFIRINOX (FFX) among patients who underwent resection of high-risk PDAC. Patients and MethodsThe study design was a modified 3+3. Cohort 1 received 5-fraction SBRT to 33 Gy to the tumor bed and 25 Gy to elective nodes followed by 6 cycles of full dose FFX. After toxicity review, cohort 2 had SBRT and were switched to modified FFX (mFFX). Cohort 3 had 1 cycle of Cy/GVAX followed by SBRT, mFFX, and 4 cycles of maintenance Cy/GVAX with 6-month Cy/GVAX boosts until progression. Results19 patients were enrolled with a median follow-up of 36.2 months. To be eligible, patients were required to have close/positive margins (within ≤1 mm) (71%) and/or lymph node metastasis (79%). Overall, 63% of patients had both. In cohort 1, 67% of patients received 6 cycles of FFX; in cohort 2, 75% received 6 cycles of modified FFX. In cohort 3, 12 patients received the first dose of Cy/GVAX and SBRT with 10 individuals (83%) receiving 6 cycles of mFFX. Cohort 3 had acceptable levels of grade ≥3 thrombocytopenia, neutropenia, and diarrhea after two cycles of mFFX. Median OS/DFS for the overall cohort and cohort 3 was 36.2/18.2 months and 61.3/24.1 months, respectively. 1-year and 2-year OS for cohort 3 was 83%/75%, respectively. At last follow-up (median= x), 5 patients were alive (42%) in cohort 3. ConclusionThis is the first prospective trial to evaluate adjuvant GVAX, Cy, SBRT, and mFFX in resected PDAC patients with high-risk features. This combination regimen was well tolerated with limited toxicity and promising survival outcomes, warranting future studies to validate this regimen in the adjuvant setting.

Nutritional Glutamine-Modified Iron-Delivery System with Enhanced Endocytosis for Ferroptosis Therapy of Pancreatic Tumors.

Heterogeneous reprogrammed nutrient metabolic networks formed by oncogenes exhibit the potential for exploring novel druggable targets and developing innovative anticancer therapeutics. Herein, based on the heterogeneous metabolic characteristics of glutamine (Gln) addiction in pancreatic cancer cells, an iron-delivery system (IDS) with enhanced endocytosis is designed for efficient ferroptosis therapy. The IDS is characterized by Gln modification and can be recognized as a source of Gln nutrients for efficient endocytic uptake by pancreatic tumor cells. Because the IDS is flexible to combine with amino acid-like components, the IDS with enhanced endocytosis is further produced by loading the Gln transporter inhibitor of V9302. V9302 is capable of suppressing molecular Gln uptake via transporter ASCT2, which generates Gln deprivation to direct metabolic reprogramming of cancer cells and enhances cellular uptake of Gln-modified IDS via RAS-stimulated macropinocytosis. The enhanced endocytosis and high iron content of IDS facilitate ferroptosis in mice pancreatic tumor models; thus, an amino acid-like ferroptosis inducer of l-buthionine sulfoximine (BSO) is further combined. The enhanced endocytosis resulting from the synergism of Gln and V9302 enables the efficient delivery of iron and BSO for ferroptosis tumor therapy. This work provides an alternative approach for enhancing intracellular drug delivery of the tumors with heterogeneous nutrient metabolism by virtue of combining nutrient-modified nanodrugs with the corresponding nutrient transporter inhibitors.

Pivotal roles for cancer cell-intrinsic mPGES-1 and autocrine EP4 signaling in suppressing antitumor immunity.

Tumor cell-derived prostaglandin E2 (PGE2) is a tumor cell-intrinsic factor that supports immunosuppression in the tumor microenvironment (TME) by acting on the immune cells, but the impact of PGE2 signaling in tumor cells on the immunosuppressive TME is unclear. We demonstrate that deleting the PGE2 synthesis enzyme or disrupting autocrine PGE2 signaling through EP4 receptors on tumor cells reverses the T cell-low, myeloid cell-rich TME, activates T cells, and suppresses tumor growth. Knockout (KO) of Ptges (the gene encoding the PGE2 synthesis enzyme mPGES-1) or the EP4 receptor gene (Ptger4) in KPCY (KrasG12D P53R172H Yfp CrePdx) pancreatic tumor cells abolished growth of implanted tumors in a T cell-dependent manner. Blockade of the EP4 receptor in combination with immunotherapy, but not immunotherapy alone, induced complete tumor regressions and immunological memory. Mechanistically, Ptges- and Ptger4-KO tumor cells exhibited altered T and myeloid cell attractant chemokines, became more susceptible to TNF-α-induced killing, and exhibited reduced adenosine synthesis. In hosts treated with an adenosine deaminase inhibitor, Ptger4-KO tumor cells accumulated adenosine and gave rise to tumors. These studies reveal an unexpected finding - a nonredundant role for the autocrine mPGES-1/PGE2/EP4 signaling axis in pancreatic cancer cells, further nominating mPGES-1 inhibition and EP4 blockade as immune-sensitizing therapy in cancer.

Oncolytic Coxsackievirus B3 Strain PD-H Is Effective Against a Broad Spectrum of Pancreatic Cancer Cell Lines and Induces a Growth Delay in Pancreatic KPC Cell Tumors In Vivo

Pancreatic cancer is one of the deadliest cancers globally, with limited success from existing therapies, including chemotherapies and immunotherapies like checkpoint inhibitors for patients with advanced pancreatic ductal adenocarcinoma (PDAC). A promising new approach is the use of oncolytic viruses (OV), a form of immunotherapy that has been demonstrated clinical effectiveness in various cancers. Here we investigated the potential of the oncolytic coxsackievirus B3 strain (CVB3) PD-H as a new treatment for pancreatic cancer. In vitro, PD-H exhibited robust replication, as measured by plaque assays, and potent lytic activity, as assessed by XTT assays, in most pancreatic tumor cell lines, outperforming two other coxsackievirus strains tested, H3N-375/1TS and CVA21. Thus, H3N-375/1TS showed efficient replication and lytic efficiency in distinctly fewer tumor cell lines, while most tumor cells were resistant to CVA21. The oncolytic efficiency of the three OV largely correlated with mRNA expression levels of viral receptors and their ability to induce apoptosis, as measured by cleaved caspase 3/7 activity in the tumor cells. In a syngeneic mouse model with subcutaneous pancreatic tumors, intratumoral administration of PD-H significantly inhibited tumor growth but did not completely stop tumor progression. Importantly, no virus-related side effects were observed. Although pancreatic tumors respond to PD-H treatment, its therapeutic efficacy is limited. Combining PD-H with other treatments, such as those aiming at reducing the desmoplastic stroma which impedes viral infection and spread within the tumor, may enhance its efficacy.

Application of LEF-1 immunohistochemical staining in the diagnosis of solid pseudopapillary neoplasm of the pancreas

IntroductionSolid pseudopapillary neoplasm (SPN) is a tumor of young females with gain-of-function mutation in catenin beta 1 gene involved in Wnt signal transduction pathway. Beta-catenin immunohistochemistry (IHC) is used to diagnose SPN. Lymphoid enhancer-binding factor 1 (LEF-1) has been recognized in the transactivation of Wnt pathway. We aim to study LEF-1 IHC in SPN and other pancreatic tumors and compare it with beta-catenin IHC. MethodsWe retrieved cases of SPN, pancreatic neuroendocrine tumor (PanNET), serous cystadenoma (SCA), ductal adenocarcinoma (PDAC) and acinar cell carcinoma (ACC) from 2011 to 2023. Formalin-fixed, paraffin-embedded blocks with adequate tumor were cut and stained with beta-catenin (B-Catenin-1 clone) and LEF-1 (EP310 clone) IHC. Cases were reviewed by two pathologists independently. Nuclear staining with LEF-1 and beta-catenin was considered as positive. ResultsOur cohort consisted of 111 cases [SPN = 59 (42 resections, 11 FNA, 6 biopsies), PDAC = 24, PanNET = 22, SCA = 5, ACC = 1]. For SPN cases male to female ratio was1:8. Age ranged from 9 to 81 years (average: 32 years). Pancreatic tail was the most common location (47 %) followed by head (28 %), body (19 %) and neck (6 %). Tumor size ranged from 1.0 to 12.2 cm (average: 5 cm). Among the SPN cases 57/59 demonstrated strong nuclear LEF-1 staining. 2/49 cases were negative for LEF-1 (both pathologist in agreement). All SPN tumors demonstrated nuclear staining with beta-catenin. Among the non-SPN tumors, beta-catenin showed nuclear staining in 2/52 cases (2 PDAC). The remaining 50 cases were negative for nuclear beta-catenin and demonstrated variable staining pattern with interpretation variability between the two pathologists. The sensitivity and specificity for LEF-1 were 97 % and 100 %, respectively, while for beta-catenin, they were 100 % and 96 % respectively. ConclusionCrisp nuclear staining of LEF-1 without background staining makes diagnostic interpretation relatively easy and accurate compared to beta-catenin IHC. This is further helpful for small biopsy samples to help differentiate SPN from mimickers such as PanNET. None of the non-SPN cases displayed nuclear LEF-1 rendering it a valuable adjunct to beta-catenin in the diagnostic evaluation of SPN.

Activation of autophagy, paraptosis, and ferroptosis by micheliolide through modulation of the MAPK signaling pathway in pancreatic and colon tumor cells

Micheliolide (MCL), a naturally occurring sesquiterpene lactone, has demonstrated significant anticancer properties through the induction of various programmed cell death mechanisms. This study aimed to explore MCL's effects on autophagy, paraptosis, and ferroptosis in pancreatic and colon cancer cells, along with its modulation of the MAPK signaling pathway. MCL was found to substantially suppress cell viability in these cancer cells, particularly in MIA PaCa-2 and HT-29 cell lines. The study identified that MCL induced autophagy by enhancing the levels of autophagy markers such as Atg7, p-Beclin-1, and Beclin-1, which was attenuated by the autophagy inhibitor 3-MA. Furthermore, MCL was found to facilitate paraptosis, indicated by decreased Alix and in-creased ATF4 and CHOP levels. It also promoted ferroptosis, as demonstrated by the reduced expression of SLC7A11, elevated TFRC levels, and increased intracellular iron. Additionally, MCL activated the MAPK signaling pathway, marked by the phosphorylation of JNK, p38, and ERK, linked with an increase in ROS production that is vital in regulating these cell death mechanisms. These findings propose that MCL is a versatile anticancer agent, capable of activating various cell death pathways by modulating MAPK signaling and ROS levels. These results emphasize the therapeutic promise of MCL in treating cancer, pointing to the necessity of further in vivo investigations to confirm these effects and determine its potential clinical uses.

Antimicrobial, Anti-biofilm, Anti-swarming, Anti-quorum Sensing Activities, and Cytotoxicity of Propolis Samples from Northeast of Türkiye

Aim of study: Studies on propolis have increased as it has been revealed that it contains biologically active molecules. In the current study, it was aimed to analyze biological activity, and cytotoxicity of ethanolic extract of three different propolis samples from Türkiye. Material and methods: The antibacterial activity of the extracts against 14 microorganisms was assessed using the agar well diffusion method and the microdilution method. Chromobacter violeceum was used in quorum-sensing assay, and Pseudomonas aeruginosa PAO1 strain was used in swarming and biofilm assays. Using the MTT test, the cytotoxic effect of the extracts was examined on the lung adenocarcinoma cell line (A549), pancreatic tumoral cell line (AR42J), breast cancer cell line (MDA-MB-231), and normal epithelial cell line (Vero). Main results: All propolis extracts were effective against 8/14 microorganisms included in the study. While all propolis extracts have shown anti-quorum sensing activity, there was not any anti-swarming and anti-biofilm activity in each sample. It was demonstrated that every propolis sample had a dose-dependent cytotoxic effect on the examined cell lines. Research highlights: Due to the biological activity shown by the propolis samples included in the study, it is considered that it has the potential to influence the creation of novel medications in the future.

Pan02 pancreatic tumor models carrying the GFP marker in mice

Animal tumor models are used for preclinical studies of drugs and cancer therapy. The aim of this work was to analyze the growth of murine pancreatic tumor cells Pan02, carrying GFP marker, injected subcutaneously (s. c.), intraperitoneally (i. p.) or orthotopically into the pancreas (ortho) of C57BL/6 mice. Mice were injected with 2 × 105 cells: s. c. in the right flank; i. p. with a syringe into the abdominal cavity, or ortho surgically under the pancreas capsule. The weight of mice was determined in the dynamics of tumor growth, and blood serum was taken to analyze the antibody response to the GFP reference protein. At the 2nd and 4th weeks of tumor growth, some mice were slaughtered and the expression of GFP by the tumor cells, as well as the composition of the immune cells in the tumor, were analyzed by flow cytometry and confocal microscopy. It was shown that with the different localization, the pancreatic tumors grew at different rates and lethality. When the tumor was injected i. p., mice lost weight with rapid tumor growth. In the ortho model, the mice increased their weight. Mortality in the s. c. and i. p. groups was comparable. In the s. c. model, the tumor grew slowly to a volume of 200-400 mm3 and stopped growing. There was no mortality in this group during the follow-up period (2 months). The same antibody response to GFP was formed with all injection schemes. The subpopulation composition of immune cells varied greatly in the different models of tumor cell administration. Regardless of the type of immune response, Pan02-GFP cells rapidly suppressed GFP gene expression in vivo. The data obtained showed that murine pancreatic tumor Pan02 is immunogenic and causes the formation of an adaptive immune response. Regardless of the presence or absence of an immune response and elimination of GFP+ cells, the tumor continued to grow in the i. p. and ortho models, but not in the s. c. one, and caused the death of mice. When conducting preclinical studies, it is necessary to use several ways of tumor cell injection to obtain a more objective result.

Abstract A010: A patient first approach using CRISPR-directed gene editing as an augmentative therapy for the treatment of pancreatic ductile adenocarcinoma

Abstract At the Gene Editing Institute, we are advancing a novel strategy for the treatment of pancreatic ductile adenocarcinoma by employing CRISPR-directed gene editing to disable the functions of key genes that block effective drug application including chemotherapy, radiation and immunotherapy. No matter how careful one is at designing a specific drug against a specific protein, ultimately, the tumor cell develops a workaround. A paradigm shift is required to truly overcome this formidable barrier. We’ve accomplished this by leveraging the effectiveness of standard care and augmenting it, thereby reducing patient suffering, increasing treatment tolerance and, most importantly, improving outcomes. With an enthusiastic response for this concept from the FDA- INTERFACT meeting, we have demonstrated that a carefully selected CRISPR/Cas complex disables the NRF2 gene in the tumor cell and significantly reduces the dose of chemotherapy required to halt pancreatic tumor cell growth, and consequently promoting cell death. The efficiency of gene editing approaches 70 % routinely, which destroys the function of NRF2 and enables additional killing of residual tumor cells by chemotherapeutic agents. As a consequence of CRISPR/Cas activity, we effectively reduce the amount of chemotherapy needed to kill tumor cells by over 20-fold. This level of reduction should enable patients to complete their treatment regimens more successfully, at lower dosages and with far fewer adverse side effects. In addition to reduced suffering, this will invariably prolong survival as we are augmenting already proven treatments. This approach is agnostic to the haplotype of the tumor cell and does not rely on specific biomarker composition; radically expanding the patient population that would be suitable for this type of treatment. We will discuss the impact of CRISPR/Cas-gene editing to disable specific genes, including NRF2 and mutant KRAS, to enable current therapies to work at greater efficacy and at lower dosages. Citation Format: London P McGill, Kelly H Banas, Gregory Tiesi, Eric B Kmiec. A patient first approach using CRISPR-directed gene editing as an augmentative therapy for the treatment of pancreatic ductile adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A010.

Abstract PR-01: Systemic targeting of therapeutic RNA to pancreatic ductal adenocarcinoma via a novel, cell-penetrating, and nucleic acid-binding monoclonal antibody

Abstract There is intense interest in developing nucleic acid ligands for immune stimulation of the tumor microenvironment via pattern recognition receptors (PRRs), particularly for treating “cold” tumors like pancreatic ductal adenocarcinoma (PDAC). However, selective delivery of intact and functional RNAs after intravenous administration in a tumor-specific manner to avoid systemic toxicity has been challenging. Many current efforts rely on the direct intra-tumoral injection of RNAs or other stimulatory immune ligands, which is therapeutically sub-optimal, especially for pancreatic tumors and metastases. Here, we present a groundbreaking and unique cancer treatment approach using a lupus-derived, cell-penetrating antibody to deliver nucleic acids to PDAC tumors in vivo. This antibody, a modified version of the initially reported 3E10-D31N, designated TMAB3, forms non-covalent complexes with RNAs. We tested our delivery platform in genetically engineered mouse models (Pdx-1 Cre KrasG12D) and flank and orthoptic allographs of pancreatic cancer (Pdx-1 Cre KrasG12D, p53R172H/- KPC cells) in immunocompetent models. Using 3p-hpRNA, an agonist of the pattern recognition receptor retinoic acid-inducible gene-I (RIG-I), we observed robust anti-tumor efficacy of systemically administered TMAB3/3p-hpRNA complexes in an orthotopic pancreatic cancer model. Treatment tripled animal survival and decreased tumor growth, specifically targeting the malignant cells, with a 1500-fold difference in RNA delivery into tumor cells versus non-malignant cells within the tumor mass. While an immunosuppressive microenvironment typically characterizes PDAC, we found that RIG-I stimulation via TMAB3/3p-hpRNA treatment elicited a potent anti-tumoral immune response characterized by induction of apoptosis in tumor cells and infiltration of CD8+ T cells using single-cell RNASeq and confirming using FACS and immunocompromised mice. In vitro and in vivo studies demonstrated that cancer-cell delivery was mediated by nucleoside transporter ENT2, which is highly expressed in PDAC compared to healthy and benign tissues. These results were recapitulated in orthogonal models of immunologically cold tumors, including melanoma and medulloblastoma. Together, these studies demonstrate that the TMAB3 antibody can 1) precisely localize and enter pancreatic tumor cells, 2) promote CD8+ T cell infiltrates, and 3) rapidly deliver RNA payloads specifically to tumors. Given the known stromal barrier in pancreatic ductal adenocarcinoma, TMAB3 provides a novel targeted delivery platform for a broad range of therapeutics for these difficult-to-treat tumors. Citation Format: Diana Martinez-Saucedo, Elias Quijano, Zaira Ianniello, Madison Rackear, Yanfeng Liu, Denise Hegan, Haoting Chen, Xinning Shan, Robert Tseng, Deanne Yugawa, Natasha Pinto-Medici, Sumedha Chowdhury, Ranjit S Bindra, Marie E Robert, W. Mark Saltzman, Luisa F Escobar-Hoyos, Peter M Glazer. Systemic targeting of therapeutic RNA to pancreatic ductal adenocarcinoma via a novel, cell-penetrating, and nucleic acid-binding monoclonal antibody [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-01.

Abstract A015: Tissue MUC5AC expression predicts recurrence patterns following resection in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDA) has consistently poor outcomes, even for early-stage tumors that undergo resection (>70%), despite completion of prescribed perioperative systemic therapy. Mucin 5AC (MUC5AC), a heavy glycoprotein, exists in two major glycoforms: heavily glycosylated mature (MM) and less glycosylated immature (IM) forms. MM is located in the apical region and extracellular space, whereas IM is in the perinuclear region. Our previous work demonstrated the association between MM and treatment response and outcomes in resected PDA after neoadjuvant therapy (NAT). In this study, we investigate the impact of MUC5AC tissue expression in resected PDA samples on recurrence site characteristics (local (LR) vs. distant metastasis (mets) vs. both LR and mets). Resected PDA formalin-fixed paraffin-embedded tissue blocks from January 2010 to June 2021 were obtained from the Ohio State University biorepository. Immunohistochemistry was performed to study the expression for MM and IM using monoclonal antibodies 45M1 and CLH2, respectively, and H-scores (0-300) were calculated. Logistic regression was used to study this association of interest. We had 100 R-PDA (43 received NAT, and 57 had upfront surgery (UpS)) available for testing. The median age of diagnosis was 65 years, and 50% were males. Most of the patients in the NAT group received FOLFIRINOX (n=36) and received gemcitabine/nab-paclitaxel (n=5) or FOLFOX (n=2). The median number of doses received is 6 (range 2-9). The results in these groups can be summarized as follows: a) 35/43 had recurrence (LR=7, mets=21, and LR+mets=7), with the liver being the most common site of metastasis (13/28) followed by lung (5/28) and peritoneum (5/28), b) Higher IM expression (mean H-score) was significantly (p=0.0275) higher in LR+mets (H-score 196) than in LR (H-score 69) or mets (H-score 115) groups, c) Higher MM expression (mean H-score) was also significantly different among these groups (LR vs. mets vs. LR+mets = 81 vs. 120 vs. 206, p= 0.0358), e) similar trend of mean H-scores was noted in FOLFIRINOX sub-group (LR vs. mets vs. LR+mets = 205 vs. 109 vs. 60, p=0.0185 for IM and 65 vs. 116 vs. 205, p=0.0329 for MM). No significant association between recurrence patterns and tissue MUC5AC expression in the UpS group. These findings concur with our prior observations, underscoring the clinical significance of MUC5AC in resected PDA post-NAT and suggesting its potential role in facilitating pancreatic tumor cell metastasis. Although larger prospective studies are needed to confirm these results, our study highlights MUC5AC as a potential therapeutic target to prevent metastasis in early-stage PDA, potentially improving overall outcomes. Citation Format: Ashish Manne, Lianbo Yu, Ashwini Esnakula. Tissue MUC5AC expression predicts recurrence patterns following resection in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A015.

Abstract B055: Harnessing cytomegalovirus immunity against pancreatic tumors for immunotherapy

Abstract Immunotherapy has had very limited success in pancreatic cancer, due to its low mutational burden and immunosuppressive microenvironment. Our approach consists in redirecting pre- existing antiviral immunity against pancreatic tumors by delivering viral antigens using the tumor penetrating peptide iRGD .This peptide, targets the tumor vasculature through av integrins and neuropilin-1, delivering conjugated or co-administered cargo to tumors. Here we used mouse cytomegalovirus (CMV) as an infection model. CMV is a β-herpesvirus that induces a strong T-cell response in mice and humans, comprising >10% of all circulating CD4 and CD8 T cells mostly with effector-memory phenotype. Importantly, human CMV infects over 60% of the world’s population rendering it a suitable candidate for translation. Methods: Mice latently infected with CMV were orthotopically implanted with KPC pancreatic tumor cells and treated with systemic injections of vehicle or iRGD plus CMV class I and II binding peptides. Another cohort of age matched uninfected mice was used as a control. Tumor growth and mouse weight were monitored twice a week and CMV specific immune responses were measured in spleen, liver and tumor by flow cytometry, using tetramer staining and CMV specific peptide recall. Results: CMV infected mice receiving iRGD+CMV peptides responded to treatment as evidenced by delayed tumor growth associated with increased tumor necrosis and T cell infiltration. In addition, flow cytometry analysis of tumor, liver and spleen showed a significant increase in CMV specific T cells preferentially in the tumor. Surprisingly, these T cells preferentially infiltrated tumors regardless of the use of iRGD for tumor targeting of CMV peptides. Survival studies showed a marked increase in median survival, reaching 42 days in the infected and treated group, compared to 25 days in the vehicle treated one. The survival benefit was very similar in the presence or absence of iRGD. Combining this strategy with anti- PD1 and or anti-IL10R did not significantly improve the benefits of CMV therapy alone. On the other hand, combination with low dose gemcitabine (5mg/kg) significantly improved tumor growth delay and survival in the combination compared to either therapy alone. The median survival reached 49 days in the combination, compared to 39 for gemcitabine or CMV therapy alone and 32 for vehicle.Conclusions: We have recently performed single cell RNA sequencing in tumors from infected and CMV peptide or vehicle treated mice and will analyze the transcriptional profile and TCR sequence of the tumor infiltrating T cells. Preliminary analysis of this data shows a massive T cell infiltration and an increase in dendritic cells and macrophages in infected and treated mice. Taken together, this data shows we can deliver antigens to pancreatic tumors and elicit an anti-tumor immune response that results in delayed tumor growth and has a survival benefit. This is a mutation agnostic approach with high translational value, since more than 60% of the population has previous CMV immunity. Citation Format: Remi Marrocco, Jay Patel, Rithika Medari, Siming Sun, Kevin Gulay, Alexei Martsinkovskiy, Simon Brunel, Eduardo Lucero-Meza, Evangeline Mose, Andrew Lowy, Chris Benedict, Tatiana Hurtado de Mendoza. Harnessing cytomegalovirus immunity against pancreatic tumors for immunotherapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B055.

Blocking tumor-intrinsic MNK1 kinase restricts metabolic adaptation and diminishes liver metastasis.

Dysregulation of the mitogen-activated protein kinase interacting kinases 1/2 (MNK1/2)-eukaryotic initiation factor 4E (eIF4E) signaling axis promotes breast cancer progression. MNK1 is known to influence cancer stem cells (CSCs); self-renewing populations that support metastasis, recurrence, and chemotherapeutic resistance, making them a clinically relevant target. The precise function of MNK1 in regulating CSCs, however, remains unexplored. Here, we generated MNK1 knockout cancer cell lines, resulting in diminished CSC properties in vitro and slowed tumor growth in vivo. Using a multiomics approach, we functionally demonstrated that loss of MNK1 restricts tumor cell metabolic adaptation by reducing glycolysis and increasing dependence on oxidative phosphorylation. Furthermore, MNK1-null breast and pancreatic tumor cells demonstrated suppressed metastasis to the liver, but not the lung. Analysis of The Cancer Genome Atlas (TCGA) data from breast cancer patients validated the positive correlation between MNK1 and glycolytic enzyme protein expression. This study defines metabolic perturbations as a previously unknown consequence of targeting MNK1/2, which may be therapeutically exploited.

Tumor and α-SMA-expressing stromal cells in pancreatic neuroendocrine tumors have a distinct RNA profile depending on tumor grade.

Alpha-smooth muscle actin (α-SMA) expression in the stroma is linked to the presence of cancer-associated fibroblasts and is known to correlate with worse outcomes in various tumors. In this study, using a GeoMx digital spatial profiling approach, we characterized the gene expression of the tumor and α-SMA-expressing stromal cell compartments in pancreatic neuroendocrine tumors (PanNETs). The profiling was performed on tissues from eight retrospective cases (three grade 1, four grade 2, and one grade3). Selected regions of interest were segmented geometrically based on tissue morphology and fluorescent signals from synaptophysin and α-SMA markers. The α-SMA-expressing stromal-cell-associated genes were involved in pathways of extracellular matrix modification, whereas, in tumor cells, the gene expression profiles were associated with pathways involved in cell proliferation. The comparison of gene expression profiles across all three PanNET grades revealed that the differences between grades are not only present at the level of the tumor but also in the α-SMA-expressing stromal cells. Furthermore, the tumor cells from regions with a rich presence of adjacent α-SMA-expressing stromal cells revealed an upregulation of matrix metalloproteinase-9 (MMP9) expression in grade 3 tumors. This study provides an in-depth characterization of gene expression profiles in α-SMA-expressing stromal and tumor cells, and outlines potential crosstalk mechanisms.

Retraction Note: Oncolysis of pancreatic tumour cells by a γ34.5-deleted HSV-1 does not rely upon Ras-activation, but on the PI 3-kinase pathway.

Retraction Note: Oncolysis of pancreatic tumour cells by a γ34.5-deleted HSV-1 does not rely upon Ras-activation, but on the PI 3-kinase pathway.