Pancreatic Tumor Xenografts Research Articles

Cadherin-17 Targeted Near-Infrared Photoimmunotherapy for Treatment of Gastrointestinal Cancer.

In cancer photodynamic therapy (PDT), a photosensitizer taken up by cancer cells can generate reactive oxygen species upon near-infrared light activation to induce cancer cell death. To increase PDT potency and decrease its adverse effect, one approach is to conjugate the photosensitizer with an antibody that specifically targets cancer cells. In the present study, IR700, a hydrophilic phthalocyanine photosensitizer, was conjugated to the humanized monoclonal antibody ARB102, which binds specifically cadherin-17 (CDH17 aka CA17), a cell surface marker highly expressed in gastrointestinal cancer to produce ARB102-IR700. Photoimmunotherapy (PIT) of gastrointestinal cancer cell lines was conducted by ARB102-IR700 treatment and near-infrared light irradiation. The results showed that ARB102-IR700 PIT could induce cell death in CDH17-positive cancer cells with high potency. In a co-culture model, CDH17-negative and CDH17-overexpressing SW480 cells were labeled with distinct fluorescent dyes and cultured together prior to PIT treatment. The results confirmed that ARB102-IR700 PIT could kill CDH17-positive cells specifically, while leaving the adjacent CDH17-negative cells unaffected. An in vivo efficacy study was conducted using a pancreatic adenocarcinoma AsPC-1 xenograft tumor model in nude mice. Fluorescence scanning indicated that ARB102-IR700 accumulated specifically in the tumor sites. To perform PIT, at 24 and 48 h postinjection, mice were irradiated with a 680 nm laser at the tumor site to activate the photosensitizer. It was shown that ARB102-IR700 PIT could inhibit tumor growth significantly. In summary, this study demonstrated that the novel ARB102-IR700 is a promising agent for PIT in gastrointestinal cancers.

Carrier-Free Nanoassembly of Curcumin-Erlotinib Conjugate for Cancer Targeted Therapy.

Anticancer drug-loaded nanoparticles have been explored extensively to decrease side effects while improving their therapeutic efficacy. However, due to the low drug loading content, premature drug release, nonstandardized carrier structure, and difficulty in predicting the fate of the carrier, only a few nanomedicines have been approved for clincial use. Herein, a carrier-free nanoparticle based on the self-assembly of the curcumin-erlotinib conjugate (EPC) is developed. The EPC nanoassembly exhibits more potent cell killing, better antimigration, and anti-invasion effects for BxPC-3 pancreatic cancer cells than the combination of free curcumin and erlotinib. Furthermore, benefiting from both passive and active tumor targeting effect, EPC nanoassembly can effectively accumulate in the tumor tissue in a xenograft pancreatic tumor mouse model. Consequently, EPC effectively reduces the growth of pancreatic tumors and extends the median survival time of the tumor-bearing mice from 22 to 68 days. In addition, no systemic toxicity is detected in the mice receiving EPC treatment. Attributed to the uniformity of the curcumin-erlotinib conjugate and easiness of scaling up, it is expected that the EPC can be translated into a powerful tool in fighting against pancreatic cancer and other epidermal growth factor receptor positive cancers.

Radiosensitization of human pancreatic cancer by piperlongumine analogues

Radiotherapy is commonly used to treat advanced pancreatic cancers and can improve survival by 2 months in combination with gemcitabine. However, prognosis and survival improvement remain unsatisfactory, and effective therapies are urgently needed. Piperlongumine has been demonstrated to have therapeutic potentials against various cancers. In this study, we synthesized a series of piperlongumine derivatives and provided evidence that piperlongumine derivatives could be used as effective radiosensitizers in pancreatic cancer. Two compounds enhanced the radiosensitivity of Panc-1 and SW1990 cells. In a pancreatic bi-flank xenograft tumor model, they significantly inhibited tumor growth. Piperlongumine derivatives could induce reactive oxygen species (ROS) expression and regulate the Keap1-Nrf2 protective pathway with enhancement of radiation-induced DNA damage, G2/M-phase cell cycle arrest, and apoptosis. Collectively, our data offer a proof of concept for the use of piperlongumine derivatives as a novel class of radiosensitizers for the treatment of pancreatic cancer.

Repurposing Pimavanserin, an Anti-Parkinson Drug for Pancreatic Cancer Therapy

Despite major advances in cancer treatment, pancreatic cancer is still incurable and the treatment outcomes are limited. The aggressive and therapy-resistant nature of pancreatic cancer warrants the need for novel treatment options for pancreatic cancer management. Drug repurposing is emerging as an effectual strategy in the treatment of various diseases, including cancer. In the present study, we evaluated the anticancer effects of pimavanserin tartrate (PVT), an antipsychotic drug used for the treatment of Parkinson disease psychosis. PVT significantly suppressed the proliferation and induced apoptosis in various pancreatic cancer cells and gemcitabine-resistant cells with minimal effects on normal pancreatic epithelial cells and lung fibroblasts. Growth-suppressive and apoptotic effects of PVT were mediated by the inhibition of the Akt/Gli1 signaling axis. The oral administration of PVT suppressed subcutaneous and orthotopic pancreatic tumor xenografts by 51%–77%. The chronic administration of PVT did not demonstrate any general signs of toxicity or change in behavioral activity of mice. Our results indicate that pancreatic tumor growth suppression by PVT was orchestrated by the inhibition of Akt/Gli1 signaling. Since PVT is already available in the clinic with an established safety profile, our results will accelerate its clinical development for the treatment of patients with pancreatic cancer.

Tracking the expression of therapeutic protein targets in rare cells by antibody-mediated nanoparticle labelling and magnetic sorting.

Molecular-level features of tumours can be tracked using single-cell analyses of circulating tumour cells (CTCs). However, single-cell measurements of protein expression for rare CTCs are hampered by the presence of a large number of non-target cells. Here, we show that antibody-mediated labelling of intracellular proteins in the nucleus, mitochondria and cytoplasm of human cells with magnetic nanoparticles enables analysis of target proteins at the single-cell level by sorting the cells according to their nanoparticle content in a microfluidic device with cell-capture zones sandwiched between arrays of magnets. We used the magnetic labelling and cell-sorting approach to track the expression of therapeutic protein targets in CTCs isolated from blood samples of mice with orthotopic prostate xenografts and from patients with metastatic castration-resistant prostate cancer. We also show that mutated proteins that are drug targets or markers of therapeutic response can be directly identified in CTCs, analysed at the single-cell level and used to predict how mice with drug-susceptible and drug-resistant pancreatic tumour xenografts respond to therapy.

Multimodal Targeted Nanoparticle-Based Delivery System for Pancreatic Tumor Imaging in Cellular and Animal Models.

Pancreatic ductal adenocarcinoma (PDAC), which ranks forth on the cancer-related death statistics still is both a diagnostic and a therapeutic challenge. Adenocarcinoma of the exocrine human pancreas originates in most instances from malignant transformation of ductal epithelial cells, alternatively by Acinar-Ductal Metaplasia (ADM). RA-96 antibody targets to a mucin M1, according to the more recent nomenclature MUC5AC, an extracellular matrix component excreted by PDAC cells. In this study, we tested the usability of multimodal nanoparticle carrying covalently coupled RA-96 Fab fragments for pancreatic tumor imaging. In order to make and evaluate a novel, better targeting, theranostic nanoparticle, iron nanoparticles and the optical dye indocyanin green (ICG) were encapsulated into the cationic sphingomyelin (SM) consisting liposomes. RA-96 Fab fragment was conjugated to the liposomal surface of the nanoparticle to increase tumor homing ability. ICG and iron nanoparticle-encapsulated liposomes were studied in vitro with cells and (i) their visibility in magnetic resonance imaging (MRI), (ii) optical, (iii) Magnetic particle spectroscopy (MPS) and (iv) photoacoustic settings was tested in vitro and also in in vivo models. The targeting ability and MRI and photoacoustic visibility of the RA-96-nanoparticles were first tested in vitro cell models where cell binding and internalization were studied. In in vivo experiments liposomal nanoparticles were injected into the tail vain using an orthotopic pancreatic tumor xenograft model and subcutaneous pancreatic cancer cell xenografts bearing mice to determine in vivo targeting abilities of RA-96-conjugated liposomes Results: Multimodal liposomes could be detected by MRI, MPS and by photoacoustic imaging in addition to optical imaging showing a wide range of imaging utility. The fluorescent imaging of ICG in pancreatic tumor cells Panc89 and Capan-2 revealed an increased association of ICG-encapsulated liposomes carrying RA-96 Fab fragments in vitro compared to the control liposomes without covalently linked RA-96. Fluorescent molecular tomography (FMT) studies showed increased accumulation of the RA96-targeted nanoparticles in the tumor area compared to non-targeted controls in vivo. Similar accumulation in the tumor sites could be seen with liposomal ferric particles in MRI. Fluorescent tumor signal was confirmed by using an intraoperative fluorescent imaging system, which showed fluorescent labeling of pancreatic tumors. These results suggest that RA-96-targeted liposomes encapsulating ICG and iron nanoparticles can be used to image pancreatic tumors with a variety of optical and magnetic imaging techniques. Additionally, they might be a suitable drug delivery tool to improve treatment of PDAC patients.

Molecular Imaging of the Tumor Microenvironment Reveals the Relationship between Tumor Oxygenation, Glucose Uptake, and Glycolysis in Pancreatic Ductal Adenocarcinoma.

Molecular imaging approaches for metabolic and physiologic imaging of tumors have become important for treatment planning and response monitoring. However, the relationship between the physiologic and metabolic aspects of tumors is not fully understood. Here, we developed new hyperpolarized MRI and electron paramagnetic resonance imaging procedures that allow more direct assessment of tumor glycolysis and oxygenation status quantitatively. We investigated the spatial relationship between hypoxia, glucose uptake, and glycolysis in three human pancreatic ductal adenocarcinoma tumor xenografts with differing physiologic and metabolic characteristics. At the bulk tumor level, there was a strong positive correlation between 18F-FDG-PET and lactate production, while pO2 was inversely related to lactate production and 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) uptake. However, metabolism was not uniform throughout the tumors, and the whole tumor results masked different localizations that became apparent while imaging. 18F-FDG uptake negatively correlated with pO2 in the center of the tumor and positively correlated with pO2 on the periphery. In contrast to pO2 and 18F-FDG uptake, lactate dehydrogenase activity was distributed relatively evenly throughout the tumor. The heterogeneity revealed by each measure suggests a multimodal molecular imaging approach can improve tumor characterization, potentially leading to better prognostics in cancer treatment. SIGNIFICANCE: Novel multimodal molecular imaging techniques reveal the potential of three interrelated imaging biomarkers to profile the tumor microenvironment and interrelationships of hypoxia, glucose uptake, and glycolysis.

Selective Induction of Cellular Toxicity and Anti-tumor Efficacy by N-Methylpiperazinyl Diarylidenylpiperidone and its Pro-nitroxide Conjugate through ROS-mediated Mitochondrial Dysfunction and G2/M Cell-cycle Arrest in Human Pancreatic Cancer.

Pancreatic adenocarcinoma is an aggressive cancer with poor clinical prognosis and limited therapeutic options. There is a significant lack of effective, safe, and targeted therapies for successful treatment of pancreatic cancer. In this report, we describe the anticancer efficacy of two novel compounds, N-methylpiperazinyl diarylidenylpiperidone (L-2663) and its pro-nitroxide conjugate (HO-4589) evaluated on human pancreatic adenocarcinoma (AsPC-1) cell line and xenograft tumor in mice. Using flow cytometry, we determined the effect of the L-2663 and HO-4589 drugs in inducing mitochondrial toxicity, triggering cell-cycle arrest, and apoptosis. EPR spectroscopy was used to quantify cellular uptake, metabolic conversion and stability of HO-4589 in cells and in vivo monitoring of tumor oxygenation as a function of growth. The results established different antiproliferative efficacy of the L-2663 and HO-4589 compounds, with a targeted action on cancer cells while being less toxic to noncancerous cells. The study may have important implications in the future designs of safe and effective chemotherapeutic agents for the treatment of pancreatic cancer.

Preclinical study of oncolytic adenovirus-mediated cytotoxic gene therapy with gemcitabine for chemoresistance of desmoplastic tumor.

e15507 Background: Pancreatic cancer is a highly lethal disease. Excessive accumulation of tumor extracellular matrix (ECM) and epithelial-to-mesenchymal transition (EMT) phenotype are two main contributors to drug resistance in desmoplastic pancreatic tumors. Methods: To overcome the limitations of various conventional therapeutics against desmoplastic pancreatic cancer, we utilized an oncolytic adenovirus (oAd) for combination therapy with gemcitabine, a standard chemotherapeutic for pancreatic cancer treatment. Here, we report the results of preclinical pharmacology and efficology studies conducted in pancreatic cancer model. Results: Efficacy studies in orthotopic pancreatic xenograft tumor model demonstrated that oAd effectively attenuated tumor cell proliferation. oAd further prevented metastasis of pancreatic cancer and sensitized pancreatic tumor to gemcitabine treatment. Furthermore, oAd augmented drug penetration and dispersion within pancreatic tumor xenografts and patient-derived pancreatic tumor spheroids. These results suggest that oAd enhance the therapeutic effect of chemotherapeutic agent in chemo-resistant and desmoplastic pancreatic tumor, thus overcoming the preexisting limitations of standard treatments. Conclusions: Overall, these results demonstrate that local administration of an oncolytic adenovirus with gemcitabine is well tolerated and support moving this investigational approach into human trials.

Evaluation of tumor growth inhibition activity of a novel multi-TRK inhibitor ABP-1119 on pancreatic tumor xenograft model.

e16741 Background: Owing to its high mortality and lack of effective treatments, there is therefore an urgent unmet need to develop novel and more effective treatments for pancreatic cancer (PC). ABP-1119 is a novel and potent multi-TRK Inhibitor for several PC-related prime tyrosine kinases (TRKs), such as EGFR, HER2, ALK, and BTK. Pre-clinical studies with ABP-1119, especially study to evaluate its tumor growth inhibition activity on pancreatic tumor xenograft model, are planned. Methods: (1) Mobility-Shift Assay used to Analyze the multi-TRK (such as EGFR, HER2, ALK, and BTK) Inhibition activity of new anti-tumor compounds, (2) CTG Assay used to analyze the inhibition activity of Mia-Paca-2 Cell Line, (3) Anti-tumor inhibition study of ABP-1119 with the pancreatic cancer nude mice, (4) Safety studies of ABP-1119 for Ames, hERG, and maximum tolerated dose (MTD). Results: It was determined that its multi-TRK inhibition activity (IC50) of ABP-1119 was 0.9nM to EGFR, 4.8nM to HER2, 0.9nM to ALK, and 2.1nM to BTK, respectively. Its inhibition activity for Cell Line Mia-Paca-2 was 0.06 µM. In anti-tumor inhibition study with the Mia-Paca-2 tumor nude mice for 14 days, the anti-tumor inhibition rate of ABP-1119 (50 mg/kg, QD) was over 82% (vs Erlotinib as a positive control, 50mg/kg, QD, inhibition rate: 48%), and no any death and other serious side effects were observed during the nude mice tests. Moreover, for other safety issues, its Ames is negative and hERG is > 30 µM, and no test-article related death or adverse events occurred in MTD studies with ABP-1119 (100mg/kg, QD) for 14 days. ABP-1119 also had very good metabolic stability in Human (T1/2 = 2.5hr). Conclusions: Based on our completed preclinical study results, ABP-1119 is a novel and potent multi-TRK Inhibitor, showing excellent enzymatic activity, prominent in-vitro anti-cancer activity, and good tumor growth inhibition activity with tolerable toxicity in pancreatic tumor xenograft in nude mice model. It is warranted to continue further investigation in pancreatic cancer.

Pseudostellaria heterophylla Extract Polysaccharide H-1-2 Suppresses Pancreatic Cancer by Inhibiting Hypoxia-Induced AG2

We aimed to examine the therapeutic potential of polysaccharide H-1-2, a bioactive component of Pseudostellaria heterophylla, against pancreatic cancer, as well as to demonstrate the underlying molecular mechanisms. Invasion and migration of pancreatic cells treated with H-1-2 were evaluated. A xenograft tumor mouse model was established to assess the effect of H-1-2 on tumor growth. Expression levels of hypoxic inducible factor-1α (HIF1α) and anterior gradient 2 (AGR2) were measured in pancreatic cells after H-1-2 treatment. Luciferase report and chromatin immunoprecipitation assays were conducted to investigate HIF1α regulation on AGR2. AGR2 expression was re-introduced into pancreatic cells to assess the role of AGR2 as a downstream effector of hypoxia after H-1-2 treatment. H-1-2 inhibited invasion and migration of pancreatic cancer cells, repressed xenograft pancreatic tumor growth, and increased survival of mice. H-1-2 repressed AGR2 expression in pancreatic cancer cells through the hypoxia response element (HRE) in its promoter region. Ectopic AGR2 expression partially negated the H-1-2 inhibitory effect on invasion and migration of pancreatic cells and on xenograft pancreatic tumors growth, and it also compromised the H-1-2 promotional effect on survival of mice. We conclude that H-1-2 suppresses pancreatic cancer by inhibiting hypoxia-induced AGR2 expression, supporting further investigation into its efficacy against pancreatic cancer in clinical settings.

Monitoring Dual VEGF Inhibition in Human Pancreatic Tumor Xenografts With Dynamic Contrast-Enhanced Ultrasound.

Background:Association of drugs acting against different antiangiogenic mechanisms may increase therapeutic effect and reduce resistance. Noninvasive monitoring of changes in the antiangiogenic response of individual tumors could guide selection and administration of drug combinations. Noninvasive detection of early therapeutic response during dual, vertical targeting of the vascular endothelial growth factor pathway was investigated in an ectopic subcutaneous xenograft model for human pancreatic tumor.Methods:Dynamic contrast-enhanced ultrasound 12 MHz was used to monitor tumor-bearing Naval Medical Research Institute mice beginning 15 days after tumor implantation. Mice received therapy from 15 to 29 days with sorafenib (N = 9), ziv-aflibercept (N = 11), combined antiangiogenic agents (N = 11), and placebo control (N = 14). Sorafenib (BAY 43-9006; Nexavar), a multikinase inhibitor acting on Raf kinase and receptor tyrosine kinases—including vascular endothelial growth factor receptors 2 and 3—was administered daily (60 mg/kg, per os). Ziv-aflibercept (ZALTRAP), a high-affinity ligand trap blocking the activity of vascular endothelial growth factor A, vascular endothelial growth factor B, and placental growth factor was administered twice per week (40 mg/kg, intraperitoneally).Results:Functional evaluation with dynamic contrast-enhanced ultrasound indicated stable tumor vascularization for the control group while revealing significant and sustained reduction after 1 day of therapy in the combined group (P = .007). There was no survival benefit or penalty due to drug combination. The functional progression-free survival assessed with dynamic contrast-enhanced ultrasound was significantly higher for the 3 treated groups; whereas, the progression-free survival based on tumor size did not discriminate therapeutic effect.Conclusions:Dynamic contrast-enhanced ultrasound, therefore, presents strong potential to monitor microvascular modifications during antiangiogenic therapy, a key role to monitoring antiangiogenic combining therapy to adapt dose range drug.

MicroRNA-4516 suppresses pancreatic cancer development via negatively regulating orthodenticle homeobox 1.

Pancreatic cancer remains one of the most lethal human cancers without efficient therapeutic strategy. MicoRNAs (miRNAs) are a group of small non-coding RNAs involved in multiple biological processes including tumor development and progression. In this study, we investigated the expression and function of miR-4516 in pancreatic cancer. MiR-4516 was low-expressed in pancreatic cancer tissues and cell lines. Overexpression of miR-4516 inhibited pancreatic cancer cell proliferation, migration and invasion, while promoted cell apoptosis in vitro. Further, overexpression of miR-4516 suppressed xenograft pancreatic tumor growth in vivo. Bioinformatics analysis was performed and miR-4516 was predicted to negatively regulate orthodenticle homeobox 1 (OTX1) expression by binding to its 3'-UTR. Consistently, OTX1 was highly expressed in pancreatic cancer tissues and cell lines. Knockdown of OTX1 expression suppressed pancreatic cancer cell migration and invasion, with down-regulated MMP2 and MMP9 expression. Moreover, we demonstrated that miR-4516 regulated pancreatic cancer cell growth, migration, invasion and apoptosis via targeting OTX1. Overexpression of OTX1 could partially abrogate the inhibitory effect of miR-4516. Taken together, we conclude that miR-4516 could function as a tumor suppressor via targeting OTX1. These findings suggest that miR-4516/OTX1 axis might be a novel therapeutic target for miRNA-based therapy for pancreatic cancer patients.

Development of a Tumor-Responsive Nanopolyplex Targeting Pancreatic Cancer Cells and Stroma.

Desmoplasia plays a pivotal role in promoting pancreatic cancer progression and is associated with poor clinical outcome. Targeting the desmoplastic tumor microenvironment in combination with chemotherapy is therefore a promising strategy for pancreatic cancer therapy. Here, we report a novel biodegradable copolymer to codeliver LY2109761 (a TGF-β receptor I/II inhibitor) and CPI-613 (a novel chemotherapy agent) to desmoplastic stroma and tumor cells, respectively, in the tumor microenvironment. Hydrophobic CPI-613 is conjugated to the hydrophilic copolymer via a newly designed MMP-2-responsive linker to form a trigger-responsive nanopolyplex. LY2109761 is hydrophobic and encapsulated into the hydrophobic core of the nanopolyplex. The resulting nanopolyplex is modified with a plectin-1-targeting peptide to enhance the accumulation of the nanopolyplex in pancreatic tumors. The nanopolyplex aims to normalize the stroma by blocking the interaction between tumor cells and pancreatic stellate cells to inhibit the activation of pancreatic stellate cells and subsequently reduce the dense extracellular matrix. Normalized stroma increases the penetration of the nanopolyplex into the tumor. The nanopolyplex shows enhanced accumulation in xenograft pancreatic tumors in a biodistribution study. Moreover, the targeted nanopolyplex markedly inhibits tumor growth in an orthotopic pancreatic cancer mouse model by dual-targeting tumor cells and stroma. Overall, the multifunctional nanopolyplex is a promising platform for pancreatic cancer therapy.

A squalamine derivative, NV669, as a novel PTP1B inhibitor: in vitro and in vivo effects on pancreatic and hepatic tumor growth.

NV669 is an aminosterol derived from squalamine found to possess strong anticancer effects. The aim of this study was to investigate NV669’s beneficial effects on human pancreatic and hepatic cancer models and to decipher the cellular and molecular mechanisms involved in tumor growth decrease upon treatment with NV669.Pancreatic (BxPC3, MiaPaCa-2) and hepatic (HepG2, Huh7) cancer cells were treated with NV669, and the effects recorded on proliferation, cell cycle and death. Results showed that NV669 inhibited the viability of cancer cells, induced cell cycle arrest and subsequently promoted apoptosis. This was accompanied by a decrease in the expression of cyclin B1 and phosphorylated Cdk1 and by a cleavage of pro-apoptotic caspase-8 and PARP-1. Taken together, our studies showed that NV669 inhibits the proliferation of pancreatic and hepatic cancer cells through the regulation of G2/M phase transition via the cyclin B1-Cdk1 complex. In vitro NV669 inhibits PTP1B activity and FAK expression. NV669 impacts on the expression of adhesion molecules CDH-1, -2 and -3 in BxPC3 and Huh7 lines that form cell monolayers. Consecutively NV669 induces cell detachment. This suggests that NV669 by inhibiting PTP1B induces cell detachment and apoptosis. Subsequently, our in vivo results showed that NV669 inhibited the growth of pancreatic and hepatic tumor xenografts with a significant cell cycle arrest in pre-mitotic phase and an increase of tumor cell apoptosis. Therefore, NV669 may serve as an alternative anticancer agent, used alone or in association with other medications, for the treatment of pancreatic adenocarcinoma and hepatocellular carcinoma.

Targeting Glycolysis with Epigallocatechin-3-Gallate Enhances the Efficacy of Chemotherapeutics in Pancreatic Cancer Cells and Xenografts.

Pancreatic cancer is a complex disease, in need of new therapeutic approaches. In this study, we explored the effect and mechanism of action of epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, alone and in combination with current chemotherapeutics on pancreatic cancer cell growth, focusing on glycolysis metabolism. Moreover, we investigated whether EGCG’s effect is dependent on its ability to induce reactive oxygen species (ROS). EGCG reduced pancreatic cancer cell growth in a concentration-dependent manner and the growth inhibition effect was further enhanced under glucose deprivation conditions. Mechanistically, EGCG induced ROS levels concentration-dependently. EGCG affected glycolysis by suppressing the extracellular acidification rate through the reduction of the activity and levels of the glycolytic enzymes phosphofructokinase and pyruvate kinase. Cotreatment with catalase abrogated EGCG’s effect on phosphofructokinase and pyruvate kinase. Furthermore, EGCG sensitized gemcitabine to inhibit pancreatic cancer cell growth in vitro and in vivo. EGCG and gemcitabine, given alone, reduced pancreatic tumor xenograft growth by 40% and 52%, respectively, whereas the EGCG/gemcitabine combination reduced tumor growth by 67%. EGCG enhanced gemcitabine’s effect on apoptosis, cell proliferation, cell cycle and further suppressed phosphofructokinase and pyruvate kinase levels. In conclusion, EGCG is a strong combination partner of gemcitabine reducing pancreatic cancer cell growth by suppressing glycolysis.

Phospho-valproic acid (MDC-1112) reduces pancreatic cancer growth in patient-derived tumor xenografts and KPC mice: enhanced efficacy when combined with gemcitabine.

New chemotherapeutic agents are needed for pancreatic cancer (PC). We have previously shown that phospho-valproic acid (MDC-1112) is effective in cell-line xenografts of PC. Here, we explored whether MDC-1112 is effective in additional clinically relevant animal models of PC and whether MDC-1112 enhances the anticancer effect of clinically used chemotherapeutic agents. MDC-1112 alone strongly reduced patient-derived pancreatic tumor xenograft growth, and extended survival of LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) mice. In both models, MDC-1112 inhibited STAT3 activation and its downstream signals, including Bcl-xL and cyclin D1. In human PC cell lines, P-V enhanced the growth inhibitory effect of gemcitabine (GEM), Abraxane and 5-FU, but not that of irinotecan. Normal human pancreatic epithelial cells were more resistant to the cytotoxic effects of MDC-1112/GEM combination. Furthermore, MDC-1112 enhanced GEM's effect on colony formation, apoptosis, cell migration, and cell invasion. In vivo, MDC-1112 and GEM, given alone, reduced patient-derived pancreatic tumor xenograft growth by 58% and 87%, respectively; whereas MDC-1112/GEM combination reduced tumor growth by 94%, inducing tumor stasis. In conclusion, MDC-1112 should be further explored as a potential agent to be used in combination with GEM for treating PC.

Novel Pyrrolo[3,2-d]pyrimidine Compounds Target Mitochondrial and Cytosolic One-carbon Metabolism with Broad-spectrum Antitumor Efficacy.

Folate-dependent one-carbon (C1) metabolism is compartmentalized into the mitochondria and cytosol and supports cell growth through nucleotide and amino acid biosynthesis. Mitochondrial C1 metabolism, including serine hydroxymethyltransferase (SHMT) 2, provides glycine, NAD(P)H, ATP, and C1 units for cytosolic biosynthetic reactions, and is implicated in the oncogenic phenotype across a wide range of cancers. Whereas multitargeted inhibitors of cytosolic C1 metabolism, such as pemetrexed, are used clinically, there are currently no anticancer drugs that specifically target mitochondrial C1 metabolism. We used molecular modeling to design novel small-molecule pyrrolo[3,2-d]pyrimidine inhibitors targeting mitochondrial C1 metabolism at SHMT2. In vitro antitumor efficacy was established with the lead compounds (AGF291, AGF320, AGF347) toward lung, colon, and pancreatic cancer cells. Intracellular targets were identified by metabolic rescue with glycine and nucleosides, and by targeted metabolomics using a stable isotope tracer, with confirmation by in vitro assays with purified enzymes. In addition to targeting SHMT2, inhibition of the cytosolic purine biosynthetic enzymes, β-glycinamide ribonucleotide formyltransferase and/or 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase, and SHMT1 was also established. AGF347 generated significant in vivo antitumor efficacy with potential for complete responses against both early-stage and upstage MIA PaCa-2 pancreatic tumor xenografts, providing compelling proof-of-concept for therapeutic targeting of SHMT2 and cytosolic C1 enzymes by this series. Our results establish structure-activity relationships and identify exciting new drug prototypes for further development as multitargeted antitumor agents.

A growth model of neuroendocrine tumor surrogates and the efficacy of a novel somatostatin-receptor–guided antibody-drug conjugate: Perspectives on clinical response?

BackgroundAs patient-derived xenografts and other preclinical models of neuroendocrine tumors for testing personalized therapeutics are lacking, we have developed a perfused, 3D bioreactor model to culture tumor surrogates from patient-derived neuroendocrine tumors. This work evaluates the duration of surrogate culture and surrogate response to a novel antibody-drug conjugate. MethodsTwenty-seven patient-derived neuroendocrine tumors were cultured. Histologic sections of a pancreatic neuroendocrine tumor xenograft (BON-1) tumor were assessed for SSTR2 expression before tumor implantation into 2 bioreactors. One surrogate was treated with an antibody-drug conjugate composed of an anti-mitotic Monomethyl auristatin-E linked to a somatostatin receptor 2 antibody. Viability and therapeutic response were assessed by pre-imaging incubation with IR-783 and the RealTime-Glo AnnexinV Apoptosis and Necrosis Assay (Promega Corporation, Madison, WI) over 6 days. A primary human pancreatic neuroendocrine tumor was evaluated similarly. ResultsMean surrogate growth duration was 34.8 days. Treated BON-1 surrogates exhibited less proliferation (1.2 vs 1.9-fold) and greater apoptosis (1.5 vs 1.1-fold) than controls, whereas treated patient-derived neuroendocrine tumor bioreactors exhibited greater degrees of apoptosis (13- vs 9-fold) and necrosis (2.5- vs 1.6-fold). ConclusionPatient-derived neuroendocrine tumor surrogates can be cultured reliably within the bioreactor. This model can be used to evaluate the efficacy of antibody-guided chemotherapy ex vivo and may be useful for predicting clinical responses.

A Novel Oxoglutarate Dehydrogenase-Like Mediated miR-214/TWIST1 Negative Feedback Loop Inhibits Pancreatic Cancer Growth and Metastasis.

As a main rate-limiting subunit of the 2-oxoglutarate dehydrogenase multienzyme complex, oxoglutarate dehydrogenase like (OGDHL) is involved in the tricarboxylic acid cycle, and frequently downregulated in human carcinoma and suppresses tumor growth. However, little is known about the role of OGDHL in human cancer, especially pancreatic cancer. Our goal is to study the underlying mechanism and define a novel signaling pathway controlled by OGDHL modulating pancreatic cancer progression. The expression and functional analysis of OGDHL, miR-214, and TWIST1 in human pancreatic cancer tissues, cell lines, and xenograft tumor model were investigated. The correlations between OGDHL and those markers were analyzed. OGDHL was downregulated in human pancreatic cancer and predicted poor prognosis. OGDHL overexpression inhibited migration and invasion of pancreatic cancer cells and suppressed pancreatic cancer tumor growth. OGDHL was shown to be negatively regulated by miR-214. TWIST1 upregulation induced miR-214 expression in pancreatic cancer. OGDHL suppressed TWIST1 expression through promoting ubiquitin-mediated proteasomal degradation of HIF1α and regulating AKT pathways. A combination of OGDHL downregulation and TWIST1 and miR-214 overexpression predicted worse prognosis in patients with pancreatic cancer. We demonstrated the prognostic value of OGDHL, miR-214, and TWIST1 in pancreatic cancer, and elucidated a novel pathway in OGDHL-regulated inhibition of pancreatic cancer tumorigenesis and metastasis. These findings may lead to new targeted therapy for pancreatic cancer through regulating OGDHL, miR-214, and TWIST1.