Prophylactic and long-lasting efficacy of senolytic CAR T cells against age-related metabolic dysfunction

Senescent cells, which accumulate in organisms over time, contribute to age-related tissue decline. Genetic ablation of senescent cells can ameliorate various age-related pathologies, including metabolic dysfunction and decreased physical fitness. While small-molecule drugs that eliminate senescent cells ('senolytics') partially replicate these phenotypes, they require continuous administration. We have developed a senolytic therapy based on chimeric antigen receptor (CAR) T cells targeting the senescence-associated protein urokinase plasminogen activator receptor (uPAR), and we previously showed these can safely eliminate senescent cells in young animals. We now show that uPAR-positive senescent cells accumulate during aging and that they can be safely targeted with senolytic CAR T cells. Treatment with anti-uPAR CAR T cells improves exercise capacity in physiological aging, and it ameliorates metabolic dysfunction (for example, improving glucose tolerance) in aged mice and in mice on a high-fat diet. Importantly, a single administration of these senolytic CAR T cells is sufficient to achieve long-term therapeutic and preventive effects.

Prophylactic and long-lasting efficacy of senolytic CAR T cells against age-related metabolic dysfunction

Senescent cells accumulate in organisms over time because of tissue damage and impaired immune surveillance and contribute to age-related tissue decline1,2. In agreement, genetic ablation studies reveal that elimination of senescent cells from aged tissues can ameliorate various age-related pathologies, including metabolic dysfunction and decreased physical fitness3-7. While small-molecule drugs capable of eliminating senescent cells (known as 'senolytics') partially replicate these phenotypes, many have undefined mechanisms of action and all require continuous administration to be effective. As an alternative approach, we have developed a cell-based senolytic therapy based on chimeric antigen receptor (CAR) T cells targeting uPAR, a cell-surface protein upregulated on senescent cells, and previously showed these can safely and efficiently eliminate senescent cells in young animals and reverse liver fibrosis8. We now show that uPAR-positive senescent cells accumulate during physiological aging and that they can be safely targeted with senolytic CAR T cells. Treatment with anti uPAR CAR T cells ameliorates metabolic dysfunction by improving glucose tolerance and exercise capacity in physiological aging as well as in a model of metabolic syndrome. Importantly, a single administration of a low dose of these senolytic CAR T cells is sufficient to achieve long-term therapeutic and preventive effects.

Optogenetic stimulation of the brainstem dorsal motor nucleus ameliorates acute pancreatitis

Introduction

Inflammation is an inherently self-amplifying process, resulting in progressive tissue damage when unresolved. A brake on this positive feedback system is provided by the nervous system which has evolved to detect inflammatory signals and respond by activating anti-inflammatory processes, including the cholinergic anti-inflammatory pathway mediated by the vagus nerve. Acute pancreatitis, a common and serious condition without effective therapy, develops when acinar cell injury activates intrapancreatic inflammation. Prior study has shown that electrical stimulation of the carotid sheath, which contains the vagus nerve, boosts the endogenous anti-inflammatory response and ameliorates acute pancreatitis, but it remains unknown whether these anti-inflammatory signals originate in the brain.

Methods

Here, we used optogenetics to selectively activate efferent vagus nerve fibers originating in the brainstem dorsal motor nucleus of the vagus (DMN) and evaluated the effects on caerulein-induced pancreatitis.

Results

Stimulation of the cholinergic neurons in the DMN significantly attenuates the severity of pancreatitis as indicated by reduced serum amylase, pancreatic cytokines, tissue damage, and edema. Either vagotomy or silencing cholinergic nicotinic receptor signaling by pre-administration of the antagonist mecamylamine abolishes the beneficial effects.

Discussion

These results provide the first evidence that efferent vagus cholinergic neurons residing in the brainstem DMN can inhibit pancreatic inflammation and implicate the cholinergic anti-inflammatory pathway as a potential therapeutic target for acute pancreatitis.

Safety and Dosing Study of a Cholecystokinin Receptor Antagonist in Non-alcoholic Steatohepatitis

High saturated fat diets have been shown to raise blood levels of cholecystokinin (CCK) and induce nonalcoholic steatohepatitis (NASH). CCK receptors are expressed on stellate cells and are responsible for hepatic fibrosis when activated. The purpose of this study was to test the safety and dose of a CCK receptor antagonist, proglumide, in human participants with NASH. An open-label single ascending dose study was conducted in 18 participants with clinical NASH based upon steatosis by liver ultrasound, elevated hepatic transaminases, and a component of the metabolic syndrome. Three separate cohorts (N = 6 each) were treated with oral proglumide for 12 weeks in a sequential ascending fashion with 800 (Cohort 1), 1,200 (Cohort 2), and 1,600 (Cohort 3) mg/day, respectively. Blood hematology, chemistries, proglumide levels, a biomarker panel for fibrosis, and symptom surveys were determined at baseline and every 4 weeks. Abdominal ultrasounds and transient elastography utilizing FibroScan were obtained at baseline and at Week 12. Proglumide was well tolerated at all doses without any serious adverse events. There was no change in body weight from baseline to Week 12. For Cohorts 1, 2, and 3, the median percent change in alanine aminotransferase was 8.42, -5.05, and -22.23 and median percent change in fibrosis score by FibroScan was 8.13, -5.44, and -28.87 (kPa), respectively. Hepatic steatosis as measured by controlled attenuation parameter score significantly decreased with proglumide, (P < 0.05). Blood microRNA biomarkers and serum 4-hydroxyproline were consistent with decreased fibrosis at Week 12 compared with baseline. These findings suggest proglumide exhibits anti-inflammatory and anti-fibrotic properties and this compound is well tolerated in participants with NASH.

Abstract C084: Oncogenic KRAS signaling drives the activation of tissue-resident fibroblasts and is required to maintain CAF heterogeneity in pancreatic cancer

The complexity of the tumor microenvironment (TME) is one of the distinguishing features of pancreatic ductal adenocarcinoma (PDA) and is responsible for patients’ poor response to therapies. The heterogeneity of cancer-associated fibroblasts (CAFs) has been correlated to the key features of the stroma that contribute to making PDA the third-leading cause of cancer-related deaths in the United States. The recent development of FDA-approved drugs against oncogenic KRAS opened a new therapeutic avenue for the treatment of tumors that have KRAS as their driver oncogene, such as PDA. However, the precise mechanisms driving the development of the TME and the contribution of KRAS to these processes have yet to be elucidated. This poses a challenge for the prediction of the effects of KRAS inhibition on established PDA tumors. By employing spatial transcriptomic technologies on various murine models recapitulating different stages of tumor initiation and progression, from acute and chronic inflammation to PanIN and overt PDA, we were able to observe distinctive changes in the activation status of pancreatic fibroblasts. These resident activated fibroblasts (RAFs) display expression of discrete markers brought upon by inflammation (inflammatory RAFs, iRAFs) or specific to oncogenic KRAS activation (myofibroblastic RAFs, myRAFs). Importantly, these RAF populations are maintained in established tumors and are identifiable in human PDA. To assess the consequences of the disruption of KRAS signaling on CAFs and RAFs, we employed a PDA mouse model that allows for the irreversible excision of KrasG12V, the FPC model (KrasFrt-LSL-G12V-Frt; p53LSL-R172H; PDX-CRE; Rosa26FlpOERT2). Through a combination of single-cell RNA sequencing (scRNA-seq), spatial transcriptomics and fluorescent in situ hybridization combined with immunofluorescence (immunoFISH) on FPC mice before and after KrasG12V deletion, we demonstrate the profound impact of Kras ablation on the TME composition. A deep remodeling of the stroma as well as significant changes in the proportion of CAF subtypes were evident. Interestingly, we observed a decrease in CAFs with a concomitant increase in RAFs. Our results suggest that the activation of oncogenic Kras in pre-neoplastic lesions drives a unique paracrine signaling that shapes the TME and is required to maintain the CAF population in PDA.

Citation Format: Giuseppina Caligiuri, Jennifer S. Thalappillil, Mojdeh Shakiba, Sandeep Nadella, Juliene Hinds, Elise Courtois, William F. Flynn, Brinda Alagesan, Georgi N. Yordanov, Benjamin Kaminow, Paul Robson, Pedro A. Perez-Mancera, Jonathan Preall, Alexander Dobin, Youngku Park, David A. Tuveson. Oncogenic KRAS signaling drives the activation of tissue-resident fibroblasts and is required to maintain CAF heterogeneity in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C084.

Abstract A050: Analysis of methods to improve engagement of under-represented and socioeconomically deprived patients in clinical research

The current under-representation of racial and ethnic minorities and socio-economically disadvantaged participants in clinical trials represents an important problem, because it reduces generalizability of trial results and should urgently be addressed in all diseases. Decentralized trials may improve engagement of under-represented populations with long-standing health disparities and may be relevant to patients with pancreatic cancer who would benefit from at home trial participation. We completed a fully decentralized randomized double-blind phase II clinical trial in New York State for participants with mild-to-moderate COVID-19. Electronic data were collected for 28 days (5 vital readings and 1 survey with 20 questions per day) from 55 non-hospitalized participants. Home monitoring devices, HIPAA compliant data submission technology, and internet access were provided free-of-charge. We enrolled 40% White, 33% Black or African American and 27% Other/Mixed/Unknown participants. Of these, 25% self-identified as Hispanic or Latino. This exceeded national and New York state averages of minority populations, in contrast with the current clinical trial landscape. We found that the local area within a 30-minute return car journey from our main research hospital disproportionately over-represented socio-economically advantaged white inhabitants. We found that decentralization enabled the inclusion of participants living up to a 2-hour journey from this hospital in socio-economically deprived geographies with higher minority race representation. We excluded selection bias, by demonstrating that our trial population represented the differences of social deprivation observed between races at the national and state level (p = 0.003). In addition to trial enrollment, completeness of trial data has an important impact on the veracity of trial results. Half our participants were assigned a dedicated team member to make telephone call reminders if participants had not submitted data by mid-day despite of a pre-ceding automated notification to the supplied electronic device. Daily telephone follow-up significantly reduced missing electronic data in participants living above the median deprivation index (submitted data per day 4 out of 6 vs 6 out of 6: p = 0.03), thereby aiding equitable data collection from traditionally under-represented participant groups. Our findings require further validation and refinement from multiple centers and expansion to patients with reduced mobility and cachexia due to progressing pancreatic cancer. Also, other factors such as language assistance and recruitment methods, need to be addressed in clinical trials to mitigate against their negative impact on equitable recruitment. Nevertheless, for now we identify decentralization combined with engagement telephone calls as readily actionable methods to improve inclusion of under-represented participants in clinical trials.

Citation Format: Hassal Lee, Alexander Shakeel Bates, Richard Dima, Sandeep Nadella, Nicole Jordan-Martin, Christina Brennan, Tobias Janowitz. Analysis of methods to improve engagement of under-represented and socioeconomically deprived patients in clinical research [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A050.

Does Chronic Use of High Dose Proton Pump Inhibitors Increase Risk for Pancreatic Cancer?

OBJECTIVES

To analyze whether use of proton pump inhibitors increase the risk for pancreatic cancer in a mouse model and human clinical cohorts.

METHODS

p48-Cre/LSL-KrasG12D mice that develop precancerous pancreatic intraepithelial neoplasia (PanINs) were treated with low- or high-dose proton pump inhibitors (PPIs) orally for 1 and 4 months. The mechanism for the cholecystokinin receptor 2 (CCK-2R) activation was investigated in vitro. Two resources were employed to analyze the risk of pancreatic cancer in human subjects with PPI use.

RESULTS

Serum gastrin levels were increased 8-fold (P < 0.0001) in mice treated with chronic high-dose PPIs, and this change correlated with an increase (P = 0.02) in PanIN grade and the development of microinvasive cancer. The CCK-2R expression was regulated by microRNA-148a in the p48-Cre/LSL-KrasG12D mice pancreas and in human pancreatic cancer cells in vitro. Proton pump inhibitor consumption in human subjects was correlated with pancreatic cancer risk (odds ratio, 1.54). A validation analysis conducted using the large-scale United Kingdom Biobank database confirmed the correlation (odds ratio, 1.9; P = 0.00761) of pancreatic cancer risk with PPI exposure.

CONCLUSIONS

This investigation revealed in both murine models and human subjects, PPI use is correlated with a risk for development of pancreatic cancer.

Abstract 3647: Oncogenic Kras drives cancer-associated fibroblast heterogeneity and substate changes in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is currently the third-leading cause of cancer-related deaths in the United States with no effective or targeted therapies to improve outcomes. Two defining features of PDAC are the dense stroma composing the bulk of the tumor mass and mutations in KRAS, the primary oncogene in most PDAC patients. Advances in knowledge on both fronts have led to promising avenues for therapeutics: recently described heterogeneity within the cancer-associated fibroblast (CAF) population residing in the stroma offers insight into the lack of success with therapies only targeting CAFs; and mutant KRAS inhibitors directed at the G12C isoform have received accelerated FDA approval for treatment of locally advanced and metastatic non-small cell lung cancer. However, the nature of this CAF heterogeneity is not yet fully understood, and any effects of KRAS blockade on the stroma have not been evaluated with consideration of this heterogeneity in mind. To assess how loss of Kras affects CAF heterogeneity and plasticity, we employed a genetically engineered mouse model (GEMM) of PDAC harboring a reversible oncogenic KrasG12V allele conditionally expressed from the endogenous Kras locus. This FPC compound mouse (KrasFrt-LSL-G12V-Frt; p53LSL-R172H; PDX-CRE; Rosa26FlpOERT2) spontaneously develops pancreatic lesions and allows for irreversible excision of the mutant Kras allele upon the application of Tamoxifen. Using single-cell RNA sequencing (scRNAseq), fluorescence in situ hybridization, and functional in vitro and in vivo approaches, we found that oncogenic Kras ablation led to tumor regression and altered cancer cell gene programs, profoundly affecting the tumor microenvironment, specifically CAF heterogeneity. Mutant Kras loss leads to decreased Tgfb1 expression in the cancer cells, but surprisingly also to increased Il1a levels, correlating with a reduction in myofibroblastic CAFs (myCAFs) and an expansion in inflammatory CAFs (iCAFs), respectively. Our results suggest that mutant Kras drives paracrine signaling that shapes CAF heterogeneity and should be considered for the development of the most effective therapeutic strategies.

Citation Format: Jennifer S. Thalappillil, Giuseppina Caligiuri, Sandeep Nadella, Brinda Alagesan, Georgi N. Yordanov, Mojdeh Shakiba, Benjamin Kaminow, Juliene Hinds, Pedro A. Perez-Mancera, Jonathan Preall, Alexander Dobin, Youngkyu Park, David A. Tuveson. Oncogenic Kras drives cancer-associated fibroblast heterogeneity and substate changes in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3647.

Oral famotidine versus placebo in non-hospitalised patients with COVID-19: a randomised, double-blind, data-intense, phase 2 clinical trial

OBJECTIVE

We assessed whether famotidine improved inflammation and symptomatic recovery in outpatients with mild to moderate COVID-19.

DESIGN

Randomised, double-blind, placebo-controlled, fully remote, phase 2 clinical trial (NCT04724720) enrolling symptomatic unvaccinated adult outpatients with confirmed COVID-19 between January 2021 and April 2021 from two US centres. Patients self-administered 80 mg famotidine (n=28) or placebo (n=27) orally three times a day for 14 consecutive days. Endpoints were time to (primary) or rate of (secondary) symptom resolution, and resolution of inflammation (exploratory).

RESULTS

Of 55 patients in the intention-to-treat group (median age 35 years (IQR: 20); 35 women (64%); 18 African American (33%); 14 Hispanic (26%)), 52 (95%) completed the trial, submitting 1358 electronic symptom surveys. Time to symptom resolution was not statistically improved (p=0.4). Rate of symptom resolution was improved for patients taking famotidine (p<0.0001). Estimated 50% reduction of overall baseline symptom scores were achieved at 8.2 days (95% CI: 7 to 9.8 days) for famotidine and 11.4 days (95% CI: 10.3 to 12.6 days) for placebo treated patients. Differences were independent of patient sex, race or ethnicity. Five self-limiting adverse events occurred (famotidine, n=2 (40%); placebo, n=3 (60%)). On day 7, fewer patients on famotidine had detectable interferon alpha plasma levels (p=0.04). Plasma immunoglobulin type G levels to SARS-CoV-2 nucleocapsid core protein were similar between both arms.

CONCLUSIONS

Famotidine was safe and well tolerated in outpatients with mild to moderate COVID-19. Famotidine led to earlier resolution of symptoms and inflammation without reducing anti-SARS-CoV-2 immunity. Additional randomised trials are required.

Minimal Change Patients Versus Obvious Chronic Pancreatitis: A Comparison of Classical Secretin Stimulation Testing Results

OBJECTIVES

The objective was to assess if the peak bicarbonate level during secretin stimulation testing (SST) differs between patients with minimal change (or small duct) chronic pancreatitis (CP) versus those with obvious CP (or large duct) versus those without CP.

METHODS

Two hundred nineteen patient records at the University of Florida who had been referred for SST were analyzed for peak bicarbonate, total volume of juice collected, age, sex, and clinical presentation.

RESULTS

Fifty-one patients with minimal change CP were identified. Thirty-three patients were felt to have advanced CP, and 135 patients did not have CP by clinical criteria. The peak bicarbonate and total volume of pancreatic juice collected was significantly different (P < 0.001) between all 3 groups by multiple comparison testing. The peak bicarbonate of advanced CP and minimal change groups was less than controls (P < 0.001). There was a significant difference (P < 0.05) on direct testing between peak bicarbonate in advanced CP and minimal change CP.

CONCLUSIONS

The peak bicarbonate and volume measured during SST differs among patients with minimal change CP, advanced CP and in disease controls. These results could be useful in diagnosing minimal change/early CP.

Photosensitive Ru(II) Complexes as Inhibitors of the Major Human Drug Metabolizing Enzyme CYP3A4

We report the synthesis and photochemical and biological characterization of the first selective and potent metal-based inhibitors of cytochrome P450 3A4 (CYP3A4), the major human drug metabolizing enzyme. Five Ru(II)-based derivatives were prepared from two analogs of the CYP3A4 inhibitor ritonavir, 4 and 6: [Ru(tpy)(L)(6)]Cl₂ (tpy = 2,2':6',2″-terpyridine) with L = 6,6'-dimethyl-2,2'-bipyridine (Me₂bpy; 8), dimethylbenzo[i]dipyrido[3,2-a:2',3'-c]phenazine (Me₂dppn; 10) and 3,6-dimethyl-10,15-diphenylbenzo[i]dipyrido[3,2-a:2',3'-c]phenazine (Me₂Ph₂dppn; 11), [Ru(tpy)(Me₂bpy)(4)]Cl₂ (7) and [Ru(tpy)(Me₂dppn)(4)]Cl₂ (9). Photochemical release of 4 or 6 from 7-11 was demonstrated, and the spectrophotometric evaluation of 7 showed that it behaves similarly to free 4 (type II heme ligation) after irradiation with visible light but not in the dark. Unexpectedly, the intact Ru(II) complexes 7 and 8 were found to inhibit CYP3A4 potently and specifically through direct binding to the active site without heme ligation. Caged inhibitors 9-11 showed dual action properties by combining photoactivated dissociation of 4 or 6 with efficient ¹O₂ production. In prostate adenocarcinoma DU-145 cells, compound 9 had the best synergistic effect with vinblastine, the anticancer drug primarily metabolized by CYP3A4 in vivo. Thus, our study establishes a new paradigm in CYP inhibition using metalated complexes and suggests possible utilization of photoactive CYP3A4 inhibitory compounds in clinical applications, such as enhancement of therapeutic efficacy of anticancer drugs.

Safety and efficacy of sofosbuvir/velpatasvir/voxilaprevir in post-liver transplant patients with previous direct-acting antiviral failure: Six case reports

BACKGROUND

Direct-acting antiviral (DAA) therapy regimens are highly effective at eliminating hepatitis C virus (HCV) infection but rates of sustained virologic response (SVR) are lower in patients with decompensated cirrhosis or hepatocellular carcinoma. Since many of these patients will be referred for liver transplant, they will require retreatment after transplantation. Sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) is recommended by guidelines as the preferred regimen to treat HCV in DAA-experienced patients following liver transplant however there is limited data.

CASE SUMMARY

We present the cases of six liver transplant recipients who had previous treatment failure with sofosbuvir-based DAA therapy prior to transplantation and who then received SOF/VEL/VOX after transplant.

CONCLUSION

This case series demonstrate the real-world efficacy and safety of SOF/VEL/VOX in the post liver transplant setting. Treatment was successful with all patients achieving SVR, it was well tolerated, and there were minimal drug-drug interactions with their immunosuppressants.

Cholecystokinin Receptor Antagonist Therapy Decreases Inflammation and Fibrosis in Chronic Pancreatitis

BACKGROUND AND AIMS

Chronic pancreatitis is associated with recurrent inflammation, pain, fibrosis, and loss of exocrine and endocrine pancreatic function and risk of cancer. We hypothesized that activation of the CCK receptor contributes to pancreatitis and blockade of this pathway would improve chronic pancreatitis.

METHODS

Two murine models were used to determine whether CCK receptor blockade with proglumide could prevent and reverse histologic and biochemical features of chronic pancreatitis: the 6-week repetitive chronic cerulein injection model and the modified 75% choline-deficient ethionine (CDE) diet. In the CDE-fed model, half the mice received water supplemented with proglumide, for 18 weeks. After chronic pancreatitis was established in the cerulein model, half the mice were treated with proglumide and half with water. Histology was scored in a blinded fashion for inflammation, fibrosis and acinar ductal metaplasia (ADM) and serum lipase levels were measured. RNA was extracted and examined for differentially expressed fibrosis genes.

RESULTS

Proglumide therapy decreased pancreatic weight in the CDE diet study and the cerulein-induced chronic pancreatitis model. Fibrosis, inflammation, and ADM scores were significantly reduced in both models. Lipase values improved with proglumide but not in controls in both models. Proglumide decreased pancreas mRNA expression of amylase, collagen-4, and TGFβR2 gene expression by 44, 38, and 25%, respectively, compared to control mice.

CONCLUSION

New strategies are needed to decreased inflammation and reduce fibrosis in chronic pancreatitis. CCK receptor antagonist therapy may improve chronic pancreatitis by reversing fibrosis and inflammation. The decrease in ADM may reduce the risk of the development of pancreatic cancer.

Dual-Action Ru(II) Complexes with Bulky π-Expansive Ligands: Phototoxicity without DNA Intercalation

We report the synthesis and photochemical and biological characterization of Ru(II) complexes containing π-expansive ligands derived from dimethylbenzo[i]dipyrido[3,2-a:2',3'-c]phenazine (Me₂dppn) adorned with flanking aryl substituents. Late-stage Suzuki couplings produced Me₂dppn ligands substituted at the 10 and 15 positions with phenyl (5), 2,4-dimethylphenyl (6), and 2,4-dimethoxyphenyl (7) groups. Complexes of the general formula [Ru(tpy)(L)(py)](PF₆)₂ (8-10), where L = 4-7, were characterized and shown to have dual photochemotherapeutic (PCT) and photodynamic therapy (PDT) behavior. Quantum yields for photodissociation of monodentate pyridines from 8-10 were about 3 times higher than that of parent complex [Ru(tpy)(Me₂dppn)(py)](PF₆)₂ (1), whereas quantum yields for singlet oxygen (¹O₂) production were ∼10% lower than that of 1. Transient absorption spectroscopy indicates that 8-10 possess long excited state lifetimes (τ = 46-50 μs), consistent with efficient ¹O₂ production through population and subsequent decay of ligand-centered ³ππ* excited states. Complexes 8-10 displayed greater lipophilicity relative to 1 and association to DNA but do not intercalate between the duplex base pairs. Complexes 1 and 8-10 showed photoactivated toxicity in breast and prostate cancer cell lines with phototherapeutic indexes, PIs, as high as >56, where the majority of cell death was achieved 4 h after treatment with Ru(II) complexes and light. Flow cytometric data and rescue experiments were consistent with necrotic cell death mediated by the production of reactive oxygen species, especially ¹O₂. Collectively, this study confirms that DNA intercalation by Ru(II) complexes with π-expansive ligands is not required to achieve photoactivated cell death.

Vaccine against gastrin, a polyclonal antibody stimulator, decreases pancreatic cancer metastases

Growth of pancreatic cancer is stimulated by gastrin in both a paracrine and an autocrine fashion. Traditional therapies have not significantly improved survival, and recently pancreatic cancer has been deemed a "cold" tumor due to its poor response to immunotherapy. Strategies to improve survival of pancreatic cancer are desperately needed. In the current investigation, we studied the effects of an anti-gastrin cancer vaccine, polyclonal antibody stimulator (PAS; formerly called G17DT and Gastrimmune), used alone or in combination with a programmed cell death receptor (PD)-1 immune checkpoint antibody on pancreatic cancer growth, metastases, and the tumor microenvironment (TME). Immune-competent female C57BL/6 mice bearing syngeneic orthotopic murine pancreatic cancer treated with PAS had significantly smaller tumors and fewer metastases. Examination of the TME demonstrated decreased fibrosis with fewer M2 and more M1 tumor-associated macrophages. Expression of the E-cadherin gene was significantly increased and expression of the TGFβR2 gene was decreased compared with controls. Mice treated with PAS or the combination of PAS and PD-1 antibody exhibited significantly less tumor expression of phospho-paxillin, the focal adhesion protein β-catenin, and matrix metalloproteinase-7. This study suggests that inhibition of the cancer-promoting effects of gastrin in pancreatic cancer can decrease metastases by altering the TME and decreasing pathways that activate the epithelial mesenchymal transition. The PAS vaccine appears to change the TME, making it more susceptible to therapy with an immune checkpoint antibody. This novel combination of two immunotherapies may improve survival of pancreatic cancer by decreasing both tumor growth and metastasis formation.NEW & NOTEWORTHY Survival from advanced pancreatic cancer is poor, in part due to dense fibrosis of the tumor microenvironment, increased number of M2-polarized macrophages that promote angiogenesis and invasion, and lack of "target-specific" therapy. Herein, we report that a tumor vaccine that selectively targets gastrin decreases pancreatic cancer growth and metastases. Furthermore, the gastrin vaccine polyclonal antibody stimulator alters the tumor microenvironment rendering it more responsive to immunotherapy with a programmed cell death receptor-1 immune checkpoint antibody.

Role of colonoscopy in diagnosis of capecitabine associated ileitis: Two case reports

BACKGROUND

Capecitabine is considered a first line agent in adjuvant therapy for breast and colorectal cancer. However, cases of severe diarrhea have been reported with increasing frequency in recent years. When diarrhea is severe and prolonged, capecitabine associated ileitis should be considered as a possible etiology.

CASE SUMMARY

Herein, we present two cases of capecitabine ileitis, specifically involving the terminal ileum and ascending colon. We will demonstrate the disease course and treatment modalities applied to alleviate this condition, as well as discuss the merits of using colonoscopy to aid in diagnosis.

CONCLUSION

Ultimately our cases demonstrate that symptomatic management with traditional anti-diarrheal medications is largely ineffective. Prompt recognition and discontinuation of capecitabine is an imperative step in proper management of this condition and colonoscopy with biopsy can be helpful when the diagnosis is unclear.

Dietary fat stimulates pancreatic cancer growth and promotes fibrosis of the tumor microenvironment through the cholecystokinin receptor

The gastrointestinal peptide cholecystokinin (CCK) is released from the duodenum in response to dietary fat to aid in digestion, and plasma CCK levels are elevated with the consumption of high-fat diets. CCK is also a trophic peptide for the pancreas and has also been shown to stimulate growth of pancreatic cancer. In the current investigation, we studied the influence of a diet high in saturated fat on the growth of pancreatic cancer in syngeneic murine models before the mice became obese to exclude the confounding factors associated with obesity. The high-fat diet significantly increased growth and metastasis of pancreatic cancer compared with the control diet, and the stimulatory effect was blocked by the CCK-receptor antagonist proglumide. We then selectively knocked out the CCK receptor on the pancreatic cancer cells using clustered regularly interspaced short palindromic repeats technology and showed that without CCK-receptors, dietary fat was unable to stimulate cancer growth. We next demonstrated that dietary fat failed to influence pancreatic cancer xenograft growth in genetically engineered CCK peptide knockout mice. The tumor-associated fibrosis that is so prevalent in the pancreatic cancer microenvironment was significantly decreased with CCK-receptor antagonist therapy because fibroblasts also have CCK receptors. The CCK-receptor antagonist proglumide also altered tumor metalloprotease expression and increased tumor suppressor genes by a PCR array. Our studies confirm that a diet high in saturated fat promotes growth of pancreatic cancer and the action is mediated by the CCK-receptor pathway. NEW & NOTEWORTHY Diets high in long-chain saturated fats promote growth of pancreatic cancer independent of obesity. The mechanism through which dietary fat promotes cancer is mediated through the cholecystokinin (CCK) receptor pathway. Therapy with a CCK-receptor antagonist altered the tumor microenvironment by reducing fibrosis, increasing cluster of differentiation 8⁺ lymphocytes, increasing tumor suppressor genes, and thus decreasing metastases. Use of CCK-receptor antagonist therapy with standard chemotherapy for pancreatic cancer may improve response by altering the tumor microenvironment.

Cholecystokinin Receptor-Targeted Polyplex Nanoparticle Inhibits Growth and Metastasis of Pancreatic Cancer

BACKGROUND & AIMS

Pancreatic ductal adenocarcinoma (PDAC) remains the most aggressive malignancy with the lowest 5-year survival rate of all cancers in part owing to the lack of tumor-specific therapy and the rapid metastatic nature of this cancer. The gastrointestinal peptide gastrin is a trophic peptide that stimulates growth of PDAC in an autocrine fashion by interaction with the cholecystokinin receptor that is overexpressed in this malignancy.

METHODS

We developed a therapeutic novel polyplex nanoparticle (NP) that selectively targets the cholecystokinin receptor on PDAC. The NP was characterized in vitro and stability testing was performed in human blood. The effects of the target-specific NP loaded with gastrin small interfering RNA (siRNA) was compared with an untargeted NP and with an NP loaded with a scrambled siRNA in vitro and in 2 orthotopic models of PDAC. A polymerase chain reaction metastasis array examined differentially expressed genes from control tumors compared with tumors of mice treated with the targeted polyplex NP.

RESULTS

The polyplex NP forms a micelle that safely delivers specific gastrin siRNA to the tumor without off-target toxicity. Consistent with these findings, cellular uptake was confirmed only with the targeted fluorescently labeled NP by confocal microscopy in vitro and by IVIS fluorescent based imaging in mice bearing orthotopic pancreatic cancers but not found with untargeted NPs. Tumor uptake and release of the gastrin siRNA NP was verified by decreased cellular gastrin gene expression by quantitative reverse-transcription polymerase chain reaction and peptide expression by immunohistochemistry. Growth of PDAC was inhibited in a dose-related fashion in cell culture and in vivo. The targeted NP therapy completely blocked tumor metastasis and altered tumor-specific genes.

CONCLUSIONS

Our polyplex nanoparticle platform establishes both a strong foundation for the development of receptor-targeted therapeutics and a unique approach for the delivery of siRNA in vivo, thus warranting further exploration of this approach in other types of cancers.

Cholecystokinin receptor antagonist alters pancreatic cancer microenvironment and increases efficacy of immune checkpoint antibody therapy in mice

Advanced pancreatic ductal adenocarcinoma (PDAC) has typically been resistant to chemotherapy and immunotherapy; therefore, novel strategies are needed to enhance therapeutic response. Cholecystokinin (CCK) has been shown to stimulate growth of pancreatic cancer. CCK receptors (CCKRs) are present on pancreatic cancer cells, fibroblasts, and lymphocytes. We hypothesized that CCKR blockade would improve response to immune checkpoint antibodies by promoting influx of tumor-infiltrating lymphocytes (TILs) and reducing fibrosis. We examined the effects of CCKR antagonists or immune checkpoint blockade antibodies alone or in combination in murine models of PDAC. Monotherapy with CCKR blockade significantly decreased tumor size and metastases in SCID mice with orthotopic PDAC, and in C57BL/6 mice, it reduced fibrosis and induced the influx of TILs. Immune-competent mice bearing syngeneic pancreatic cancer (Panc02 and mT3-2D) that were treated with the combination of CCK receptor antagonists and immune checkpoint blockade antibodies survived significantly longer with smaller tumors. Tumor immunohistochemical staining and flow cytometry demonstrated that the tumors of mice treated with the combination regimen had a significant reduction in Foxp3+ T-regulatory cells and an increase in CD4+ and CD8+ lymphocytes. Masson's trichrome stain analysis revealed 50% less fibrosis in the tumors of mice treated with CCKR antagonist compared to controls and compared to checkpoint antibody therapy. CCKR antagonists given with immune checkpoint antibody therapy represent a novel approach for improving survival of PDAC. The mechanism by which this combination therapy improves the survival of PDAC may be related to the decreased fibrosis and immune cells of the tumor microenvironment.

Abstract LB-133: De novo expression of gastrin and CCK-B receptors in cell lines derived from KPC mice

Background: Animal models to study cancer progression and therapeutics are essential but these animal models are most useful when they resemble human cancers, particularly with respect to inflammation and the immune system in carcinogenesis and therapy. Hence, athymic nude mice bearing human cancer explants are being replaced by genetically modified animal models with intact immune systems. Panc02 cancer cells have been used to create a syngeneic immune competent murine model of pancreatic cancer. However, unlike human pancreatic cancer, Panc02 cells express wild-type KRAS and CCK-A type receptors (rather than CCK-B type receptors). We previously showed that the Pdx1-Cre / LSL-KrasG12D transgenic mice develop de novo CCK-B receptors with PanIN progression. Aim: The goal of this investigation was to examine cell cultures derived from the KrasG12D mice to determine if they are indeed similar to human cancers in regard to in vivo growth properties and expression of gastrin and CCK-B receptors.

Methods: Five different pancreatic cell lines were obtained that had been derived from the KPC mice (KPC1, KPC2) or organoids (MT3-2D, MT4-2D, and MT5-2D) of the KPC mice. RNA was extracted from the cell lines and evaluated for CCK-A and CCK-B receptors and the ligand gastrin. Growth studies were characterized in syngeneic C57BL/6 mice. The effects of CCK receptor blockade with proglumide was evaluated on tumor growth in vivo. Histologic sections were stained with H&E, Trichrome, and a PD-L1 Ab.Results: RT-PCR revealed that the KPC and MT-2D cells no longer express the CCK-A receptor found in normal mouse pancreas but all expressed the CCK-B receptor, characteristic of human pancreatic cancers. Gastrin expression was also detected by RT-PCR in all cells. Subcutaneous tumors grew rapidly to 1000mm3 within 21 days after inoculation of 105 cells. Tumor growth in MT3-2D tumors was significantly inhibited and survival of mice prolonged with the CCK-receptor antagonist proglumide compared to PBS controls (p=0.0048). Tumors showed extensive fibrosis characteristic of the human PDAC microenvironment and all tumors had PD-L1 expression.

Conclusion: These studies show that cell lines developed from PanIN lesions in KRAS mice exhibit phenotypic and genetic characteristics comparable to human pancreatic cancers and therefore are promising models to study the relationship of CCK receptor-mediated biology to the development and therapy of pancreatic cancer. De novo expression of the CCK-B receptor and gastrin from mouse pancreas suggests a possible relationship between CCK receptor signaling and mutant KRAS expression.Supported by NCI CA50633, CA51008, and CA194745

Citation Format: Jill P. Smith, Shangzi Wang, Louis Weiner, Sandeep Nadella. De novo expression of gastrin and CCK-B receptors in cell lines derived from KPC mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-133. doi:10.1158/1538-7445.AM2017-LB-133

Abstract 2162: Novel anti-gastrin nanoparticle inhibits growth of pancreatic cancer

Background: Receptor-targeted therapies or inhibition of growth factors have improved cancer survival. Pancreatic ductal adenocarcinoma (PDAC) markedly over-expresses the cholecystokinin-B (CCK-B) receptor and re-expression gastrin stimulates growth of PDAC by an autocrine mechanism through the CCK-B receptor. When gastrin mRNA is down regulated by RNAi techniques, PDAC growth and metastases are inhibited in animal models. However, anti-gastrin gene therapy cannot be readily used in humans unless nontoxic gene delivery strategies are implemented. The purpose of this project was to develop a unique drug delivery nanoparticle (NP) that selectively binds to the CCK-B receptor and safely delivers siRNA to down-regulate gastrin expression and inhibit growth of PDAC.

Methods: In order to develop the targeted NP, a thiol functionalized polyethylene glycol-block-poly(L-lysine) (SH-PEG-PLL) polymer was synthesized. To render the NP target-specific for the CCK-B receptor we used a maleimide link to conjugate Gastrin-10 to the PEG via Michael addition reaction. The resulting Ga-PEG-PLL was extensively purified using a PD-10 column and by dialysis. The polyplex micelle was prepared by mixing 1mg/mL of the Ga-PEG-b-PLL with a gastrin siRNA (si286 GUGCUGAGGAUGAGAACUA), which decreases gastrin mRNA 90%. The PEG protects the siRNA from degradation in solution or blood and the lysine polymer forms a micelle shielding the positive charge and eliminating toxicity. The NP was analyzed by dynamic light scattering (DLS) and zeta potential. Efficacy of the NPs to inhibit growth was tested on PANC-1 human PDAC cells that have a high number of CCK-B receptors. Cells were plated into 6-well plates overnight and then treated for 72h with PBS, 100x NP (10nM siRNA) or 50x NPs (5nM siRNA) in serum-free DMEM media. Viable cell counts were performed by trypan blue exclusion.

Results: Characterization of the functionalized polyplex NP confirmed a molecular weight of 9700 Da. Trityl deprotection and conjugation of Ga-10 to the SH-PEG-PLL polymer were confirmed by NMR which demonstrated complete removal of the trityl group and greater than 70% conjugation of the peptide to target the receptor. The polyplex NP complex was confirmed by DLS measurement, which demonstrated size distributions of 44.3 ± 0.3 and 48.2 ± 0.3 nm for receptor-targeted and untargeted polyplex respectively. Treatment of PANC-1 cancer cells with the anti-gastrin NPs significantly inhibited growth by 98% compared to untreated controls (p = 0.005).

Conclusion: A novel NP that targets the over-expressed CCK-B receptor on PDAC was successfully synthesized and characterized. The NP can deliver anti-gastrin gene therapy in the form of siRNA into human pancreatic cancer cells to significantly inhibit cell growth by downregulation of gastrin expression. This technique may provide a safe and novel gene therapy delivery method to treat those with advanced PDAC.

Supported by: Otto J Ruesch Center for the Cure of GI Cancers

Citation Format: Julian Burks, Sandeep Nadella, Abdullah Mahmud Mahmud, Scott McNeil, Jong-IN Hahm, Stephan Stern, Jill Smith. Novel anti-gastrin nanoparticle inhibits growth of pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2162.

Sensing of phosphates by using luminescent Eu(III) and Tb(III) complexes: application to the microalgal cell Chlorella vulgaris

Phenanthroline-based chiral ligands L(1) and L(2) as well as the corresponding Eu(III) and Tb(III) complexes were synthesized and characterized. The coordination compounds show red and green emission, which was explored for the sensing of a series of anions such as F(-), Cl(-), Br(-), I(-), NO3(-), NO2(-), HPO4(2-), HSO4(-), CH3COO(-), and HCO3(-). Among the anions, HPO4(2-) exhibited a strong response in the emission property of both europium(III) and terbium(III) complexes. The complexes showed interactions with the nucleoside phosphates adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). Owing to this recognition, these complexes have been applied as staining agents in the microalgal cell Chlorella vulgaris. The stained microalgal cells were monitored through fluorescence microscopy and scanning electron microscopy. Initially, the complexes bind to the outer cell wall and then enter the cell wall through holes in which they probably bind to phospholipids. This leads to a quenching of the luminescence properties.

Lanthanide(III) complexes of bis-semicarbazone and bis-imine-substituted phenanthroline ligands: solid-state structures, photophysical properties, and anion sensing

Phenanthroline-based hexadentate ligands L(1) and L(2) bearing two achiral semicarbazone or two chiral imine moieties as well as the respective mononuclear complexes incorporating various lanthanide ions, such as La(III), Eu(III), Tb(III), Lu(III), and Y(III) metal ions, were synthesized, and the crystal structures of [ML(1)Cl(3)] (M=La(III), Eu(III), Tb(III), Lu(III), or Y(III)) complexes were determined. Solvent or water molecules act as coligands for the rare-earth metals in addition to halide anions. The big Ln(III) ion exhibits a coordination number (CN) of 10, whereas the corresponding Eu(III), Tb(III), Lu(III), and Y(III) centers with smaller ionic radii show CN=9. Complexes of L(2), namely [ML(2)Cl(3)] (M=Eu(III), Tb(III), Lu(III), or Y(III)) ions could also be prepared. Only the complex of Eu(III) showed red luminescence, whereas all the others were nonluminescent. The emission properties of the Eu derivative can be applied as a photophysical signal for sensing various anions. The addition of phosphate anions leads to a unique change in the luminescence behavior. As a case study, the quenching behavior of adenosine-5'-triphosphate (ATP) was investigated at physiological pH value in an aqueous solvent. A specificity of the sensor for ATP relative to adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) was found. (31)P NMR spectroscopic studies revealed the formation of a [EuL(2)(ATP)] coordination species.

The relative sensitivity of sperm, eggs and embryos to copper in the blue mussel (Mytilus trossulus)

Copper, an essential element, is toxic at elevated concentrations, and as a result of anthropogenic activities is becoming increasingly prevalent in marine environments. In this study, we examined the effects of copper on early life stages of the blue mussel, Mytilus trossulus. We assessed the impacts of increasing copper concentrations on embryo development, egg viability, sperm fertilization capacity and, in particular, on sperm swimming speed using computer-assisted sperm analysis. Sensitivity to copper followed the pattern: embryos > sperm > eggs. A dramatic increase in abnormal embryo development was observed following exposure to copper concentrations exceeding 10 microg/L. Sperm swimming speeds decreased significantly when exposed to 100 microg/L of copper, but lower doses did not influence sperm swimming speed. Copper exposure (at any tested concentration) did not affect sperm flagellum length, or alter egg viability. Based on our results, we suggest that exposure of sperm to copper may interfere with mitochondrial activity, which reduces sperm swimming speed during the extended duration of sperm motility in blue mussel.