Orthotopic Pancreatic Cancer Research Articles

Drug-repurposing by virtual and experimental screening of PFKFB3 inhibitors for pancreatic cancer therapy

Pancreatic cancer (PC) is the most frequently occurring cancer, with few effective treatments and a 5-year survival rate of only about 11%. It is characterized by stiff interstitium and pressure on blood vessels, leading to an increased glycolytic metabolism. PFKFB3 plays an important role in glycolysis, and its products (fructose-2,6-bisphosphate), which are allosteric PFK1 activators, limit the glycolytic rate. In this study, 14 PFKFB3 inhibitors were obtained by virtually screening the FDA-approved compound library. Subsequently, the in-vitro investigations confirmed that Lomitapide and Cabozantinib S-malate exhibit the excellent potential to inhibit PFKFB3. The combined administration of Lomitapide and Gemcitabine at a certain molar ratio indicated an enhanced anti-tumor effect in Orthotopic Pancreatic Cancer (OPC) models. This investigation provides a new treatment strategy for PC therapy.

Isopentyl-Deoxynboquinone Induces Mitochondrial Dysfunction and G2/M Phase Cell Cycle Arrest to Selectively Kill NQO1-Positive Pancreatic Cancer Cells.

Aims: Pancreatic cancer is among the top five leading causes of cancer-related deaths worldwide, with poor overall survival rates. Current therapies for pancreatic cancer lack tumor specificity, resulting in harmful effects on normal tissues. Therefore, developing tumor-specific agents for the treatment of pancreatic cancer is critical. NAD(P)H:quinone oxidoreductase 1 (NQO1), highly expressed in pancreatic cancers but not in associated normal tissues, makes NQO1 bioactivatable drugs a potential therapy for selectively killing NQO1-positive cancer cells. Our previous studies have revealed that the novel NQO1 bioactivatable drug deoxynyboquinone (DNQ) is 10-fold more potent than the prototypic NQO1 bioactivatable drug β-lapachone in killing of NQO1-positive cancer cells. However, DNQ treatment results in high-grade methemoglobinemia, a significant side effect that limits clinical development. Results: Here, we report for the first time on a DNQ derivative, isopentyl-deoxynboquinone (IP-DNQ), which selectively kills pancreatic ductal adenocarcinoma (PDAC) cells in an NQO1-dependent manner with equal potency to the parent DNQ. IP-DNQ evokes massive reactive oxygen species (ROS) production and oxidative DNA lesions that result in poly(ADP-ribose)polymerase-1 (PARP1) hyperactivation, mitochondrial catastrophe, and G2/M phase cell cycle arrest, leading to apoptotic and necrotic programmed cell death. Importantly, IP-DNQ treatment causes only mild methemoglobinemia in vivo, with a threefold improvement in the maximum tolerated dose (MTD) compared with DNQ, while it significantly suppresses tumor growth and extends the life span of mice in subcutaneous and orthotopic pancreatic cancer xenograft models. Innovation and Conclusion: Our study demonstrates that IP-DNQ is a promising therapy for NQO1-positive pancreatic cancers and may enhance the efficacy of other anticancer drugs. IP-DNQ represents a novel approach to treating pancreatic cancer with the potential to improve patient outcomes.

Photo-Triggered Cascade Therapy: A NIR-II AIE Luminogen Collaborating with Nitric Oxide Facilitates Efficient Collagen Depletion for Boosting Pancreatic Cancer Phototheranostics.

The dense extracellular matrix (ECM) in the pancreatic cancer severely hampers the penetration of nanodrugs, which causes inferior therapeutic efficacy. To address this issue, a multifunctional liposome, namely, Lip-DTI/NO, integrating a type-I photosensitizer DTITBT with glutathione (GSH) or heat-responsive nitric oxide (NO) donor S-nitroso-N-acetyl-D-penicillamine (SNAP) is constructed to deplete the tumor ECM, leading to enhanced drug delivery and consequently improved phototherapy. The loaded DTITBT possesses multiple functions including NIR-II fluorescence imaging, efficient superoxide radical (O2 •-) generation and excellent photothermal conversion efficiency, making it feasible for precisely pinpointing the tumor in the phototherapy process. Responding to the intracellular overexpressed glutathione or heat produced by photothermal effect of DTITBT, NO can be released from SNAP. Upon 808nm laser irradiation, Lip-DTI/NO could selectively induce in situ generation of peroxynitrite anion (ONOO-) in tumor after cascade processes including O2 •- production, GSH or heat-triggered NO release, and rapid reaction between O2 •- and NO. The generated ONOO- could activate the expression of endogenous matrix metalloproteinases which could efficiently digest collagen of tumor ECM, thus facilitating enhanced penetration and accumulation of Lip-DTI/NO in tumor. In vivo evaluation demonstrates the notable therapeutic efficacy via ONOO--potentiated synergistic photodynamic-photothermal therapies on both subcutaneous and orthotopic pancreatic cancer model.

99mTc]Tc-labeled cyc-DX600-HYNIC as a SPECT probe for ACE2-specific pancreatic cancer imaging.

As a regulator in renin-angiotensin-aldosterone system, angiotensin-converting enzyme 2 (ACE2) closely correlated with tumor progression of pancreatic cancer, meantime, was easily affected by a variety of factors. [99mTc]Tc-cyc-DX600 SPECT was established as an ACE2-specific imaging protocol to figure out the ACE2 status in pancreatic tumor. BALB/C-NU mice were used to prepare the subcutaneous cell derived xenograft (CDX) models with HEK-293T or HEK-293T/hACE2 cells to validate ACE2 specificity of [99mTc]Tc-cyc-DX600 SPECT and establish SPECT imaging protocol. On the basis of [99mTc]Tc-cyc-DX600 SPECT and [18F]F-FDG PET/CT, ACE2-dependence on tumor size and tumor metabolism were further verified on orthotopic pancreatic cancer model with KPC cells. Immunohistochemical analysis was used to demonstrate the findings on ACE2 SPECT. [99mTc]Tc-cyc-DX600 was of superior tumor uptake in HEK-293T/hACE2 CDX than wild type (6.74 ± 0.31 %ID/mL vs 1.83 ± 0.26 %ID/mL at 1.5 h post injection (p.i.); 3.14 ± 0.31 %ID/mL vs 1.16 ± 0.15 %ID/mL at 4.5 h p.i.). For the CDX models with PANC-1 cells, a significant negative correlation between the slope of tumor volume and tumor uptake was observed (r = -0.382 for the 1-4th day; r = -0.146 for the 1-5th day; r = -0.114 for the 1-6th day; r = -0.152 for the 1-7th day; but P > 0.05 for all). For orthotopic pancreatic cancer model, the linear correlation between FDG PET and ACE2 SPECT of the pancreatic lesions was negative (r = -0.878), the quantitative values of ACE2 SPCET was positively correlated with the volume of primary lesions (r = 0.752) and also positively correlated with the quantitative values of ACE2 immunohistochemical analysis (r = 0.991). Conclusively, [99mTc]Tc-cyc-DX600 SPECT is an ACE2-specific imaging protocol with clinical translational potential, adding multidimensional information on the disease progression of pancreatic cancer.

A novel simple suture method for establishing an orthotopic pancreatic cancer mouse model: a comparative study with two conventional methods.

This study aims to evaluate the efficacy of a novel simple suture method in establishing an optimal animal model for preclinical research in pancreatic cancer. To establish a novel simple suture method, the tumor fragment was placed on the tail of the pancreas and securely wrapped into the pancreas, and compared with two conventional methods: the cell injection method and the tumor fragment embedding method. Subsequently, emission tomography/computed tomography scanning, gross anatomy observation, hematoxylin and eosin staining, and immunohistochemistry staining were performed to assess the effectiveness of these methods. The emission tomography/computed tomography scanning and anatomical examinations confirmed the successful construction of orthotopic pancreatic cancer models using all three methods. Histopathological analysis of the orthotopic masses and metastatic lesions revealed malignant transformation with tumor infiltration into normal tissue. Comparative analysis demonstrated that the cell injection method was easy to perform but resulted in poor uniformity of tumor size and had high costs. The tumor fragment embedding method exhibited excellent uniformity of tumor size, with the highest tumor growth rates and a greater pancreatic impairment. In contrast, the novel simple suture method featured a relatively simple surgical procedure, slower growth rates, good uniformity of tumor size, and minimal pancreatic impairment. The novel simple suture method is the optimal protocol for establishing an orthotopic pancreatic cancer mouse model, providing a robust foundation for preclinical studies on pancreatic cancer.

Clinically relevant orthotopic pancreatic cancer models for adoptive T cell transfer therapy.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor. Prognosis is poor and survival is low in patients diagnosed with this disease, with a survival rate of ~12% at 5 years. Immunotherapy, including adoptive T cell transfer therapy, has not impacted the outcomes in patients with PDAC, due in part to the hostile tumor microenvironment (TME) which limits T cell trafficking and persistence. We posit that murine models serve as useful tools to study the fate of T cell therapy. Currently, genetically engineered mouse models (GEMMs) for PDAC are considered a "gold-standard" as they recapitulate many aspects of human disease. However, these models have limitations, including marked tumor variability across individual mice and the cost of colony maintenance. Using flow cytometry and immunohistochemistry, we characterized the immunological features and trafficking patterns of adoptively transferred T cells in orthotopic PDAC (C57BL/6) models using two mouse cell lines, KPC-Luc and MT-5, isolated from C57BL/6 KPC-GEMM (KrasLSL-G12D/+p53-/- and KrasLSL-G12D/+p53LSL-R172H/+, respectively). The MT-5 orthotopic model best recapitulates the cellular and stromal features of the TME in the PDAC GEMM. In contrast, far more host immune cells infiltrate the KPC-Luc tumors, which have less stroma, although CD4+ and CD8+ T cells were similarly detected in the MT-5 tumors compared with KPC-GEMM in mice. Interestingly, we found that chimeric antigen receptor (CAR) T cells redirected to recognize mesothelin on these tumors that signal via CD3ζ and 41BB (Meso-41BBζ-CAR T cells) infiltrated the tumors of mice bearing stroma-devoid KPC-Luc orthotopic tumors, but not MT-5 tumors. Our data establish for the first time a reproducible and realistic clinical system useful for modeling stroma-rich and stroma-devoid PDAC tumors. These models shall serve an indepth study of how to overcome barriers that limit antitumor activity of adoptively transferred T cells.

Prognostic value of RRM1 and its effect on chemoresistance in pancreatic cancer.

Pancreatic cancer (PC) remains a lethal disease, and gemcitabine resistance is prevalent. However, the biomarkers suggestive of gemcitabine resistance remain unclear. Bioinformatic tools identified ribonucleotide reductase catalytic subunit M1 (RRM1) in gemcitabine-related datasets. A cox regression model revealed the predictive value of RRM1 with clinical features. An external clinical cohort confirmed the prognostic value of RRM1. RRM1 expression was validated in gemcitabine-resistant cells in vitro and in orthotopic PC model. CCK8, flow cytometry, transwell migration, and invasion assays were used to explore the effect of RRM1 on gemcitabine-resistant cells. The CIBERSORT algorithm investigated the impact of RRM1 on immune infiltration. The constructed nomogram based on RRM1 effectively predicted prognosis and was further validated. Moreover, patients with higher RRM1 had shorter overall survival. RRM1 expression was significantly higher in PC tissue and gemcitabine-resistant cells in vitro and in vivo. RRM1 knockdown reversed gemcitabine resistance, inhibited migration and invasion. The infiltration levels of CD4 + T cells, CD8 + T cells, neutrophils, and plasma cells correlated markedly with RRM1 expression, and communication between tumor and immune cells probably depends on NF-κB/mTOR signaling. RRM1 may be a potential marker for prognosis and a target marker for gemcitabine resistance in PC.

Micelle-Formulated Juglone Effectively Targets Pancreatic Cancer and Remodels the Tumor Microenvironment.

Pancreatic cancer remains a formidable challenge due to limited treatment options and its aggressive nature. In recent years, the naturally occurring anticancer compound juglone has emerged as a potential therapeutic candidate, showing promising results in inhibiting tumor growth and inducing cancer cell apoptosis. However, concerns over its toxicity have hampered juglone's clinical application. To address this issue, we have explored the use of polymeric micelles as a delivery system for juglone in pancreatic cancer treatment. These micelles, formulated using Poloxamer 407 and D-α-Tocopherol polyethylene glycol 1000 succinate, offer an innovative solution to enhance juglone's therapeutic potential while minimizing toxicity. In-vitro studies have demonstrated that micelle-formulated juglone (JM) effectively decreases proliferation and migration and increases apoptosis in pancreatic cancer cell lines. Importantly, in-vivo, JM exhibited no toxicity, allowing for increased dosing frequency compared to free drug administration. In mice, JM significantly reduced tumor growth in subcutaneous xenograft and orthotopic pancreatic cancer models. Beyond its direct antitumor effects, JM treatment also influenced the tumor microenvironment. In immunocompetent mice, JM increased immune cell infiltration and decreased stromal deposition and activation markers, suggesting an immunomodulatory role. To understand JM's mechanism of action, we conducted RNA sequencing and subsequent differential expression analysis on tumors that were treated with JM. The administration of JM treatment reduced the expression levels of the oncogenic protein MYC, thereby emphasizing its potential as a focused, therapeutic intervention. In conclusion, the polymeric micelles-mediated delivery of juglone holds excellent promise in pancreatic cancer therapy. This approach offers improved drug delivery, reduced toxicity, and enhanced therapeutic efficacy.

The Tautomerase Activity of Tumor Exosomal MIF Promotes Pancreatic Cancer Progression by Modulating MDSC Differentiation.

Pancreatic cancer is a deadly disease that is largely resistant to immunotherapy, in part because of the accumulation of immunosuppressive cells in the tumor microenvironment (TME). Much evidence suggests that tumor-derived exosomes (TDE) contribute to the immunosuppressive activity mediated by myeloid-derived suppressor cells (MDSC) within the pancreatic cancer TME. However, the underlying mechanisms remain elusive. Herein, we report that macrophage migration inhibitory factor (MIF) in TDEs has a key role in inducing MDSC formation in pancreatic cancer. We identified MIF in both human and murine pancreatic cancer-derived exosomes. Upon specific shRNA-mediated knockdown of MIF, the ability of pancreatic cancer-derived exosomes to promote MDSC differentiation was abrogated. This phenotype was rescued by reexpression of the wild-type form of MIF rather than a tautomerase-null mutant or a thiol-protein oxidoreductase-null mutant, indicating that both MIF enzyme activity sites play a role in exosome-induced MDSC formation in pancreatic cancer. RNA sequencing data indicated that MIF tautomerase regulated the expression of genes required for MDSC differentiation, recruitment, and activation. We therefore developed a MIF tautomerase inhibitor, IPG1576. The inhibitor effectively inhibited exosome-induced MDSC differentiation in vitro and reduced tumor growth in an orthotopic pancreatic cancer model, which was associated with decreased numbers of MDSCs and increased infiltration of CD8+ T cells in the TME. Collectively, our findings highlight a pivotal role for MIF in exosome-induced MDSC differentiation in pancreatic cancer and underscore the potential of MIF tautomerase inhibitors to reverse the immunosuppressive pancreatic cancer microenvironment, thereby augmenting anticancer immune responses.

Sono-Activatable Semiconducting Polymer Nanoreshapers Multiply Remodel Tumor Microenvironment for Potent Immunotherapy of Orthotopic Pancreatic Cancer.

Due to the complicated tumor microenvironment that compromises the efficacies of various therapies, the effective treatment of pancreatic cancer remains a big challenge. Sono-activatable semiconducting polymer nanoreshapers (SPNDN H) are constructed to multiply remodel tumor microenvironment of orthotopic pancreatic cancer for potent immunotherapy. SPNDN H contain a semiconducting polymer, hydrogen sulfide (H2 S) donor, and indoleamine 2,3-dioxygenase (IDO) inhibitor (NLG919), which are encapsulated by singlet oxygen (1 O2 )-responsive shells with modification of hyaluronidase (HAase). After accumulation in orthotopic pancreatic tumor sites, SPNDN H degrade the major content of tumor microenvironment hyaluronic acid to promote nanoparticle enrichment and immune cell infiltration, and also release H2 S to relieve tumor hypoxia via inhibiting mitochondrion functions. Moreover, the relieved hypoxia enables amplified sonodynamic therapy (SDT) under ultrasound (US) irradiation with generation of 1 O2 , which leads to immunogenic cell death (ICD) and destruction of 1 O2 -responsive components to realize sono-activatable NLG919 release for reversing IDO-based immunosuppression. Through such a multiple remodeling mechanism, a potent antitumor immunological effect is triggered after SPNDN H-based treatment. Therefore, the growths of orthotopic pancreatic tumors in mouse models are almost inhibited and tumor metastases are effectively restricted. This study offers a sono-activatable nanoplatform to multiply remodel tumor microenvironment for effective and precise immunotherapy of deep-tissue orthotopic tumors.

Lithium chloride induces apoptosis by activating endoplasmic reticulum stress in pancreatic cancer

Lithium compounds, a classic class of metal complex medicine that target GSK 3β and are widely known as mood-stabilizer, have recently been reported as potential anti-tumor drugs. The objective of this investigation was to explore the anticancer potential of lithium chloride (LiCl) and elucidate its mode of action in pancreatic cancer cells. The MTT, colony formation, and Edu assay were used to evaluate the impact of LiCl on pancreatic cancer cell proliferation. Various methods were employed to investigate the anti-tumor activity of LiCl and its underlying mechanisms. Cell cycle analysis and apoptosis detection assays were utilized for in vitro experiments, while the orthotopic pancreatic cancer mouse model was employed to evaluate the effectiveness of LiCl treatment in vivo. Furthermore, the impact of LiCl on the proliferation of patient-derived organoids was also studied. The results demonstrated that LiCl inhibited the proliferation of pancreatic cancer (PC) cells, induced G2/M phase arrest, and activated apoptosis. Notably, the triggering of endoplasmic reticulum (ER) stress by LiCl was observed, leading to the activation of the PERK/CHOP/GADD34 pathway, which subsequently promoted apoptosis in PC cells. In the future, Lithium compounds could become an essential adjunct in the treatment of human pancreatic cancer.

Commensal bacterial hybrid nanovesicles improve immune checkpoint therapy in pancreatic cancer through immune and metabolic reprogramming

Harnessing the immunomodulatory ability of the microbiota, such as fecal microbiota transplantation (FMT), has emerged as a promising strategy to improve cancer immunotherapy. However, the lack of standardization in fecal material formulation and safety concerns have hindered clinical application. To overcome these limitations, we developed a high-yielding method by hybridizing bacteria protoplast-derived membrane nanovesicles (PDNVs) from three colon bacteria strains that have been associated with favorable responses to immune checkpoint therapy, including Akkermansia muciniphila, Bifidobacterium longum, and Bifidobacterium breve. The resulting hybrid nanovesicles (HNVs) are composed mainly of cytoplasmic membrane proteins inherited from the originating bacteria but lack pyrogens such as lipopolysaccharide and lipoteichoic acid. Our study demonstrated that HNVs have superior targeting abilities to tumors and peripheral lymphoid organs, leading to greater capability in inducing innate immune activation, dendritic cell maturation and antigen presentation, as well as tumor microenvironment reprogramming. Combined with αPD-1 blockade therapy, HNVs efficiently inhibited the tumor growth in multiple pancreatic cancer mouse models, including Panc02 subcutaneous and liver metastatic models, and orthotopic KPC-Luc pancreatic cancer model. Mechanically, HNVs simultaneously activated the innate arm of immunity and inhibited tumor oxidative phosphorylation (OXPHOS) to reshape the tumor immune microenvironment for improved αPD-1 blockade therapy. Notably, HNVs administration gave rise to similar tumor regression rates to oral transfer of a mixture of live or inactivated bacteria during αPD-1 blockade therapy, but with fewer adverse effects such as diarrhea and colon-intestinal inflammation. Our findings present a stable, cost-effective, and safe alternative to live bacteria for regulating tumor microenvironment for improved cancer immunotherapy.

Complexation of drug and hapten-conjugated aptamer with universal hapten antibody for pancreatic cancer treatment.

Owing to a lack of reliable markers and therapeutic targets, pancreatic ductal adenocarcinoma (PDAC) remains the most lethal malignant tumor despite numerous therapeutic advances. In this study, we utilized cell-SELEX to isolate a DNA aptamer recognizing the natural conformation of the target on the cell surface. PAp7T8, an aptamer optimized by size and chemical modification, exhibited specific targeting to pancreatic cancer cells and orthotopic xenograft pancreatic tumors. To confer therapeutic functions to the aptamer, we adopted a drug-conjugated oligobody (DOligobody) strategy. Monomethyl auristatin E was used as a cytotoxic drug, digoxigenin acted as a hapten, and the humanized anti-digoxigenin antibody served as a universal carrier of the aptamer. The resulting PAp7T8-DOligobody showed extended in vivo half-life and markedly inhibited tumor growth in an orthotopic pancreatic cancer xenograft model without causing significant toxicity. Therefore, PAp7T8-DOligobody represents a promising novel therapeutic delivery platform for PDAC.

Interventional hydrogel microsphere vaccine as an immune amplifier for activated antitumour immunity after ablation therapy

The response rate of pancreatic cancer to chemotherapy or immunotherapy pancreatic cancer is low. Although minimally invasive irreversible electroporation (IRE) ablation is a promising option for irresectable pancreatic cancers, the immunosuppressive tumour microenvironment that characterizes this tumour type enables tumour recurrence. Thus, strengthening endogenous adaptive antitumour immunity is critical for improving the outcome of ablation therapy and post-ablation immune therapy. Here we present a hydrogel microsphere vaccine that amplifies post-ablation anti-cancer immune response via releasing its cargo of FLT3L and CD40L at the relatively lower pH of the tumour bed. The vaccine facilitates migration of the tumour-resident type 1 conventional dendritic cells (cDC1) to the tumour-draining lymph nodes (TdLN), thus initiating the cDC1-mediated antigen cross-presentation cascade, resulting in enhanced endogenous CD8+ T cell response. We show in an orthotopic pancreatic cancer model in male mice that the hydrogel microsphere vaccine transforms the immunologically cold tumour microenvironment into hot in a safe and efficient manner, thus significantly increasing survival and inhibiting the growth of distant metastases.

Activatable Semiconducting Polymer Pro-nanomodulators for Deep-Tissue Sono-immunotherapy of Orthotopic Pancreatic Cancer.

Immunotherapy has provided a promising modality for cancer treatment, while it often has the issues of limited response rates and potential off-target side effects in clinical practice. We herein report the construction of semiconducting polymer pro-nanomodulators (SPpMs) with ultrasound (US)-mediated activatable pharmacological actions for deep-tissue sono-immunotherapy of orthotopic pancreatic cancer. Such SPpMs consist of a sonodynamic semiconducting polymer backbone grafted with poly(ethylene glycol) chains linked with two immunomodulators (a programmed death-ligand 1 blocker and an indoleamine 2,3-dioxygenase inhibitor) via a singlet oxygen (1 O2 )-cleavable segment. In view of the excellent sonodynamic property of the semiconducting polymer core, SPpMs enable effective generation of 1 O2 under US treatment, even in a deep-tissue depth up to 12 cm. The generated 1 O2 not only ablates tumors via a sonodynamic effect and induces immunogenic cell death, but also destroys the 1 O2 -cleavable segments to allow in situ release of immunomodulators in tumors. This synergetic action results in boosted antitumor immune response via reversing two tumor immunosuppressive pathways. As such, SPpMs mediate deep-tissue sono-immunotherapy to completely eradicate orthotopic pancreatic cancer and effectively prevent tumor metastasis. Moreover, such an immune activation reduces the possibility of immune-related adverse events. This study thus provides a smart activatable nanoplatform for precise immunotherapy of deep-seated tumors.

Activatable Semiconducting Polymer Pro‐nanomodulators for Deep‐Tissue Sono‐immunotherapy of Orthotopic Pancreatic Cancer

AbstractImmunotherapy has provided a promising modality for cancer treatment, while it often has the issues of limited response rates and potential off‐target side effects in clinical practice. We herein report the construction of semiconducting polymer pro‐nanomodulators (SPpMs) with ultrasound (US)‐mediated activatable pharmacological actions for deep‐tissue sono‐immunotherapy of orthotopic pancreatic cancer. Such SPpMs consist of a sonodynamic semiconducting polymer backbone grafted with poly(ethylene glycol) chains linked with two immunomodulators (a programmed death‐ligand 1 blocker and an indoleamine 2,3‐dioxygenase inhibitor) via a singlet oxygen (1O2)‐cleavable segment. In view of the excellent sonodynamic property of the semiconducting polymer core, SPpMs enable effective generation of 1O2 under US treatment, even in a deep‐tissue depth up to 12 cm. The generated 1O2 not only ablates tumors via a sonodynamic effect and induces immunogenic cell death, but also destroys the 1O2‐cleavable segments to allow in situ release of immunomodulators in tumors. This synergetic action results in boosted antitumor immune response via reversing two tumor immunosuppressive pathways. As such, SPpMs mediate deep‐tissue sono‐immunotherapy to completely eradicate orthotopic pancreatic cancer and effectively prevent tumor metastasis. Moreover, such an immune activation reduces the possibility of immune‐related adverse events. This study thus provides a smart activatable nanoplatform for precise immunotherapy of deep‐seated tumors.

Transforming Growth Factor-β Blockade in Pancreatic Cancer Enhances Sensitivity to Combination Chemotherapy

Transforming growth factor-b (TGFb) plays pleiotropic roles in pancreatic cancer, including promoting metastasis, attenuating CD8 T-cell activation, and enhancing myofibroblast differentiation and deposition of extracellular matrix. However, single-agent TGFb inhibition has shown limited efficacy against pancreatic cancer in mice or humans. We evaluated the TGFβ-blocking antibody NIS793 in combination with gemcitabine/nanoparticle (albumin-bound)-paclitaxel or FOLFIRINOX (folinic acid [FOL], 5-fluorouracil [F], irinotecan [IRI] and oxaliplatin [OX]) in orthotopic pancreatic cancer models. Single-cell RNA sequencing and immunofluorescence were used to evaluate changes in tumor cell state and the tumor microenvironment. Blockade of TGFβ with chemotherapy reduced tumor burden in poorly immunogenic pancreatic cancer, without affecting the metastatic rate of cancer cells. Efficacy of combination therapy was not dependent on CD8 T cells, because response to TGFβ blockade was preserved in CD8-depleted or recombination activating gene 2 (RAG2-/-) mice. TGFβ blockade decreased total α-smooth muscle actin-positive fibroblasts but had minimal effect on fibroblast heterogeneity. Bulk RNA sequencing on tumor cells sorted exvivo revealed that tumor cells treated with TGFβ blockade adopted a classical lineage consistent with enhanced chemosensitivity, and immunofluorescence for cleaved caspase 3 confirmed that TGFβ blockade increased chemotherapy-induced cell death invivo. TGFβ regulates pancreatic cancer cell plasticity between classical and basal cell states. TGFβ blockade in orthotropic models of pancreatic cancer enhances sensitivity to chemotherapy by promoting a classical malignant cell state. This study provides scientific rationale for evaluation of NIS793 with FOLFIRINOX or gemcitabine/nanoparticle (albumin-bound) paclitaxel chemotherapy backbone in the clinical setting and supports the concept of manipulating cancer cell plasticity to increase the efficacy of combination therapy regimens.

Abstract 3701: Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer mortality in the United States. The poor prognosis is in part due to development of chemotherapy resistance, despite improvements in multiagent regimens. Our previous work demonstrated that oxidative stress plays an important role in drug resistance. Wild-type isocitrate dehydrogenase 1 (IDH1) is an important enzyme that generates cytosolic NADPH to maintain redox homeostasis and protect cancer cells from oxidative damage. Additionally, we demonstrated that ivosidenib (AG-120), an FDA-approved mutant IDH1 inhibitor, is actually a potent inhibitor of wild-type IDH1, under low magnesium and nutrient levels that are present in the tumor microenvironment. Methods: We evaluated IDH1 expression in PDAC using The Cancer Genome Atlas (TCGA). Cell viability was assessed by Trypan blue and PicoGreen in drug combination assays. Cellular reactive oxygen species (ROS) levels were determined by the DCFDA method. To further assess the therapeutic potential of AG-120 in combination with chemotherapy, tumor volume analyses were performed using patient-derived xenografts (PDX) in athymic nude mice, and survival studies were performed in C57BL/6J mice transplanted with orthotopic murine pancreatic cancer. Results: Analysis of TCGA data indicated that IDH1 is overexpressed in pancreatic cancer tumors. Treatment of MiaPaca2 and Panc1 cancer cells with 5- fluorouracil (5-FU) induced expression of wild-type IDH1 in vitro. Short-term cell viability data demonstrated that targeting IDH1 with AG-120 when combined with DNA-damaging agents (5-FU, oxaliplatin) had a synergistic effect 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 5-FU was combined with AG-120, as compared to single-agent controls. Inhibiting IDH1 impairs the ability of pancreatic cancer cells to scavenge ROS levels, enhances chemotherapy-induced apoptosis in pancreatic cancer cells via ROS-mediated damage in vitro. Both PDX tumor volume studies and overall survival analyses revealed that the combination of these AG-120 and chemotherapy synergistically enhanced anti-tumor activity and doubled the survival benefits as compared to single-agent alone. Conclusion: IDH1 plays a critical role in tumorigenesis and chemoresistance in pancreatic cancer. Our data demonstrate that IDH1 inhibition with AG-120 may enhance chemotherapy efficacy and represents an important area for future investigation in the form of clinical trials. Citation Format: Mehrdad Zarei, Omid Hajihassani, Jonathan J. Hue, Hallie J. Graor, Arian Hajihassani, Alexander W. Loftus, Luke D. Rothermel, Jordan M. Winter. Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3701.

Abstract 5191: Modeling age-related changes in the tumor microenvironment in an orthotopic immunocompetent murine pancreatic cancer model - a novel approach

Abstract Pancreatic cancer is the third leading cause of cancer-related deaths in the U.S. and is most frequently diagnosed between the ages of 65-74 years. Only 11.5% of patients are expected to survive 5 years after diagnosis. There is extensive evidence that tumor microenvironment (TME) plays a critical role in cancer progression and metastasis. Despite the fact that most patients are diagnosed over the age of 60, most preclinical murine tumor models utilize young, healthy, adolescent mice, failing to account for structural and/or functional changes in stroma and immune cells that occur in tissues over time and contribute to tumor progression. Marked differences in lifespan between mice and humans preclude natural development of many age-related physiologic changes in mice that occur in humans over the course of decades. We performed a pilot study to test our hypothesis that KPC pancreatic tumors grown orthotopically in the pancreas of genetically engineered, C57BL/6-Tg (LMNA*G608G) HClns/J mice, a model of Hutchinson-Gilford progeria syndrome with features of accelerated aging, would have altered tumor growth in comparison to tumors in age-matched wild type controls. We found that tumor growth in LMNA mice outpaced that of WT mice. Quantitative digital image analysis showed significantly reduced intratumoral infiltration of CD45+ leukocytes in LMNA mice in comparison to WT (p=0.0098). There was a significant reduction in tumor-infiltrating CD3+ T cells (p=0.038) and F4/80+ macrophages (p=0.0102). Our data supports the hypothesis that functional, age-related, immune and/or stromal changes in the TME impact pancreatic tumor growth and progression. Innovative strategies that better model age-related changes in the TME may better recapitulate the aggressive course of pancreatic cancer in aged patients. Citation Format: Morgan M. Green, Tara Fujimoto, Cullen Taniguchi, Natalie Fowlkes. Modeling age-related changes in the tumor microenvironment in an orthotopic immunocompetent murine pancreatic cancer model - a novel approach. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5191.

Synergistic Apoptosis-Ferroptosis: Oxaliplatin loaded amorphous iron oxide nanoparticles for High-efficiency therapy of orthotopic pancreatic cancer and CA19-9 levels decrease

Pancreatic cancer is a highly malignant tumor with early metastasis, poor prognosis, and resistant to existing chemotherapy drugs such as oxaliplatin (Oxp). Therefore, a nanodrug of amorphous iron oxide packaged Oxp (AIOoxp) was proposed to achieve a more efficient treatment of orthotopic pancreatic cancer than that of free Oxp. The obtained AIOoxp increased the accumulation of Pt at tumor sites and effectively reduced Oxp-induced systemic toxicity. In addition, the Fe2+/Fe3+ ions released by AIOoxp react with H2O2 through Fenton’s reaction and produce a large amount of reactive oxygen species (ROS), which further induce ferroptosis, thus promoting Oxp-induced apoptosis and achieve synergistic tumor therapy. Furthermore, AIOoxp nanoplatforms can significantly reduce the levels of carbohydrate antigen 19–9 (CA19-9), which is the most important biomarker and promoter of pancreatic cancer, suggesting favorable therapeutic effects and prognosis. Overall, this study provides new insights and solutions for the clinical treatment of pancreatic cancer.