Elevated S100B urine levels predict seizures in infants complicated by perinatal asphyxia and undergoing therapeutic hypothermia.

OBJECTIVES: Seizures (SZ) are one of the main complications occurring in infants undergoing therapeutic hypothermia (TH) due to perinatal asphyxia (PA) and hypoxic ischemic encephalopathy (HIE). Phenobarbital (PB) is the first-line therapeutic strategy, although data on its potential side-effects need elucidation. We investigated whether: i) PB administration in PA-HIE TH-treated infants affects S100B urine levels, and ii) S100B could be a reliable early predictor of SZ. METHODS: We performed a prospective case-control study in 88 PA-HIE TH infants, complicated (n=44) or not (n=44) by SZ requiring PB treatment. S100B urine levels were measured at 11 predetermined monitoring time-points from first void up to 96-h from birth. Standard-of-care monitoring parameters were also recorded. RESULTS: S100B significantly increased in the first 24-h independently from HIE severity in the cases who later developed SZ and requested PB treatment. ROC curve analysis showed that S100B, as SZ predictor, at a cut-off of 2.78 µg/L achieved a sensitivity/specificity of 63 and 84 %, positive/negative predictive values of 83 and 64 %. CONCLUSIONS: The present results offer additional support to the usefulness of S100B as a trustable diagnostic tool in the clinical daily monitoring of therapeutic and pharmacological procedures in infants complicated by PA-HIE.

BAG3 induces fibroblasts to release key cytokines involved in pancreatic cell migration.

Pancreatic ductal adenoma carcinoma (PDAC) is considered one of the deadliest solid cancers as it is usually diagnosed in advanced stages and has a poor response to treatment. The enormous effort made in the last 2 decades in the oncology field has not led to significant progress in improving early diagnosis or therapy for PDAC. The stroma of PDAC plays an active role in tumour initiation and progression and includes immune cells and stromal cells. We previously reported that Bcl2-associated athanogene (BAG3) secreted by PDAC cells activates tumour-associated macrophages to promote tumour growth. The disruption of this tumour-stroma axis by the anti-BAG3 H2L4 therapeutic antibody is sufficient to delay tumour growth and limit metastatic spreading in different PDAC preclinical models. In the present study, we examined the role of BAG3 to activate human fibroblasts (HF) in releasing cytokines capable of supporting tumour progression. Treatment of fibroblasts with recombinant BAG3 induced important changes in the organisation of the cytoskeleton of these cells and stimulated the production of interleukin-6, monocyte chemoattractant protein-1/C-C motif chemokine ligand 2, and hepatocyte growth factor. Specifically, we observed that BAG3 triggered a depolymerisation of microtubules at the periphery of the cell while they were conserved in the perinuclear area. Conversely, the vimentin-based intermediate filaments increased and spread to the edges of the cells. Finally, the conditioned medium (CM) collected from BAG3-treated HF promoted the survival, proliferation, and migration of the PDAC cells. Blocking of the PDAC-fibroblast axis by the H2L4 therapeutic anti-BAG3 antibody, resulted in inhibition of cytokine release and, consequently, the inhibition of the migratory phenotype conferred by the CM to PDAC cells.

Iron Dyshomeostasis in COVID-19: Biomarkers Reveal a Functional Link to 5-Lipoxygenase Activation.

Coronavirus disease 2019 (COVID-19) is characterized by a broad spectrum of clinical symptoms. After acute infection, some subjects develop a post-COVID-19 syndrome known as long-COVID. This study aims to recognize the molecular and functional mechanisms that occur in COVID-19 and long-COVID patients and identify useful biomarkers for the management of patients with COVID-19 and long-COVID. Here, we profiled the response to COVID-19 by performing a proteomic analysis of lymphocytes isolated from patients. We identified significant changes in proteins involved in iron metabolism using different biochemical analyses, considering ceruloplasmin (Cp), transferrin (Tf), hemopexin (HPX), lipocalin 2 (LCN2), and superoxide dismutase 1 (SOD1). Moreover, our results show an activation of 5-lipoxygenase (5-LOX) in COVID-19 and in long-COVID possibly through an iron-dependent post-translational mechanism. Furthermore, this work defines leukotriene B4 (LTB4) and lipocalin 2 (LCN2) as possible markers of COVID-19 and long-COVID and suggests novel opportunities for prevention and treatment.

Therapeutic Efficacy of the Novel Stimuli-Sensitive Nano-Ferritins Containing Doxorubicin in a Head and Neck Cancer Model.

Doxorubicin is employed alone or in combination for the treatment of several hematological and solid malignancies; despite its efficacy, there are associated cardiotoxicity limits both in its application in patients with heart disease risk factors and also in its long-term use. HFt-MP-PAS40 is a genetically engineered human ferritin heavy chain (HFt)-based construct able to efficiently entrap and deliver doxorubicin to cancer cells. HF-MP-PAS contains a short motif sequence (defined as MP) responsive to proteolytic cleavage by tumor matrix metalloproteases (MMPs), located between each HFt subunit and a masking polypeptide sequence rich in proline (P), alanine (A), and serine (S) residues (PAS). This carrier displayed excellent therapeutic efficacy in a xenogenic pancreatic cancer model in vivo, leading to a significant increase in overall animal survival in treated mice. Herein, we describe the HFt-MP-PAS40-Dox efficacy against squamous cell carcinomas of the head and neck (HNSCC) with the goal of validating the application of our nano-drug for the treatment of different solid tumors. In addition, a tolerability study in healthy mice was also performed. The results indicate that HFt-MP-PAS40-Dox produced increased anti-tumor effects both in vitro and in vivo in comparison to the free drug in several HNSCC cell lines. In the acute toxicity studies, the maximum tolerated dose (MTD) of HFt-MP-PAS40-Dox was about 3.5 higher than the free drug: 25 mg/kg versus 7 mg/kg doxorubicin equivalents. Importantly, evaluation of heart tissues provided evidence that doxorubicin is less cardio-toxic when encapsulated inside the ferritin carrier. In conclusion, HFt-MP-PAS40-Dox may be administered safely at higher doses compared with the free drug, resulting in superior efficacy to control HNSCC malignancies.

Combining ERAP1 silencing and entinostat therapy to overcome resistance to cancer immunotherapy in neuroblastoma.

BACKGROUND: Checkpoint immunotherapy unleashes tumor control by T cells, but it is undermined in non-immunogenic tumors, e.g. with low MHC class I expression and low neoantigen burden, such as neuroblastoma (NB). Endoplasmic reticulum aminopeptidase 1 (ERAP1) is an enzyme that trims peptides before loading on MHC class I molecules. Inhibition of ERAP1 results in the generation of new antigens able of inducing potent anti-tumor immune responses. Here, we identify a novel non-toxic combinatorial strategy based on genetic inhibition of ERAP1 and administration of the HDAC inhibitor (HDACi) entinostat that increase the immunogenicity of NB, making it responsive to PD-1 therapy. METHODS: CRISPR/Cas9-mediated gene editing was used to knockout (KO) the ERAP1 gene in 9464D NB cells derived from spontaneous tumors of TH-MYCN transgenic mice. The expression of MHC class I and PD-L1 was evaluated by flow cytometry (FC). The immunopeptidome of these cells was studied by mass spectrometry. Cocultures of splenocytes derived from 9464D bearing mice and tumor cells allowed the assessment of the effect of ERAP1 inhibition on the secretion of inflammatory cytokines and activation and migration of immune cells towards ERAP1 KO cells by FC. Tumor cell killing was evaluated by Caspase 3/7 assay and flow cytometry analysis. The effect of ERAP1 inhibition on the immune content of tumors was analyzed by FC, immunohistochemistry and multiple immunofluorescence. RESULTS: We found that inhibition of ERAP1 makes 9464D cells more susceptible to immune cell-mediated killing by increasing both the recall and activation of CD4+ and CD8+ T cells and NK cells. Treatment with entinostat induces the expression of MHC class I and PD-L1 molecules in 9464D both in vitro and in vivo. This results in pronounced changes in the immunopeptidome induced by ERAP1 inhibition, but also restrains the growth of ERAP1 KO tumors in vivo by remodelling the tumor-infiltrating T-cell compartment. Interestingly, the absence of ERAP1 in combination with entinostat and PD-1 blockade overcomes resistance to PD-1 immunotherapy and increases host survival. CONCLUSIONS: These findings demonstrate that ERAP1 inhibition combined with HDACi entinostat treatment and PD-1 blockade remodels the immune landscape of a non-immunogenic tumor such as NB, making it responsive to checkpoint immunotherapy.

Development of a Method for Detection of SARS-CoV-2 Nucleocapsid Antibodies on Dried Blood Spot by DELFIA Immunoassay.

Antibodies against the SARS-CoV-2 nucleocapsid protein are produced by the immune system in response to SARS-CoV-2 infection, but most available vaccines developed to fight the pandemic spread target the SARS-CoV-2 spike protein. The aim of this study was to improve the detection of antibodies against the SARS-CoV-2 nucleocapsid by providing a simple and robust method applicable to a large population. For this purpose, we developed a DELFIA immunoassay on dried blood spots (DBSs) by converting a commercially available IVD ELISA assay. A total of forty-seven paired plasma and dried blood spots were collected from vaccinated and/or previously SARS-CoV-2-infected subjects. The DBS-DELFIA resulted in a wider dynamic range and higher sensitivity for detecting antibodies against the SARS-CoV-2 nucleocapsid. Moreover, the DBS-DELFIA showed a good total intra-assay coefficient of variability of 14.6%. Finally, a strong correlation was found between SARS-CoV-2 nucleocapsid antibodies detected by the DBS-DELFIA and ELISA immunoassays (r = 0.9). Therefore, the association of dried blood sampling with DELFIA technology may provide an easier, minimally invasive, and accurate measurement of SARS-CoV-2 nucleocapsid antibodies in previously SARS-CoV-2-infected subjects. In conclusion, these results justify further research to develop a certified IVD DBS-DELFIA assay for detecting SARS-CoV-2 nucleocapsid antibodies useful for diagnostics as well as for serosurveillance studies.

Pancreatic beta-cell specific BAG3 knockout results in chronic hyperinsulinemia inducing insulin resistance.

BACKGROUND: Insulin, secreted from pancreatic islets of Langerhans, is of critical importance in regulating glucose homeostasis. Defective insulin secretion and/or the inability of tissues to respond to insulin results in insulin resistance and to several metabolic and organ alterations. We have previously demonstrated that BAG3 regulates insulin secretion. Herein we explored the consequences of beta-cells specific BAG3 deficiency in an animal model. METHODS: We generated a beta-cells specific BAG3 knockout mouse model. Glucose and insulin tolerance tests, proteomics, metabolomics, and immunohistochemical analysis were used to investigate the role of BAG3 in regulating insulin secretion and the effects of chronic exposure to excessive insulin release in vivo. RESULTS: Beta-cells specific BAG3 knockout results in primary hyperinsulinism due to excessive insulin exocytosis finally leading to insulin resistance. We demonstrate that resistance is mainly muscle-dependent while the liver remains insulin sensitive. The chronically altered metabolic condition leads in time to histopathological alterations in different organs. We observe elevated glycogen and lipid accumulation in the liver reminiscent of non-alcoholic fatty liver disease as well as mesangial matrix expansion and thickening of the glomerular basement membrane, resembling the histology of chronic kidney disease. CONCLUSION: Altogether, this study shows that BAG3 plays a role in insulin secretion and provides a model for the study of hyperinsulinemia and insulin resistance.

Tear proteomics reveals the molecular basis of the efficacy of human recombinant nerve growth factor treatment for Neurotrophic Keratopathy.

Neurotrophic Keratopathy (NK), classified as an orphan disease (ORPHA137596), is a rare degenerative corneal disease characterized by epithelial instability and decreased corneal sensitivity caused by the damage to the corneal nerves. The administration of human recombinant nerve growth factor (rhNGF) eye drops, as a licensed-in-Europe specific medication for treatment of moderate and severe NK, has added promising perspectives to the management of this disorder by providing a valid alternative to the neurotization surgery. However, few studies have been conducted to the molecular mechanism underlying the response to the treatment. Here, we carried out tears proteomics to highlight the protein expression during pharmacological treatment of NK (Data are available via ProteomeXchange with identifier PXD025408).Our data emphasized a proteome modulation during rhNGF treatment related to an increase in DNA synthesis, an activation of both BDNF signal and IL6 receptor. Furthermore, the amount of neuronal Extracellular Vesicles EVs (CD171+) correlated with the EVs carrying IL6R (CD126+) together associated to the inflammatory EVs (CD45+) in tears. Such scenario determined drug response, confirmed by an in vivo confocal microscopy analysis, showing an increase in length, density and number of nerve fiber branches during treatment. In summary, rhNGF treatment seems to determine an inflammatory micro-environment, mediated by functionalized EVs, defining the drug response by stimulating protein synthesis and fiber regeneration.

Validation of the GSP®/DELFIA® Anti-SARS-CoV-2 IgG Kit Using Dried Blood Samples for High-Throughput Serosurveillance and Standardized Quantitative Measurement of Anti-Spike S1 IgG Antibody Responses Post-Vaccination.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a major global public health crisis. In response, researchers and pharmaceutical companies worked together for the rapid development of vaccines to reduce the morbidity and mortality associated with viral infection. Monitoring host immunity following virus infection and/or vaccination is essential to guide vaccination intervention policy. Humoral immune response to vaccination can be assessed with serologic testing, and indeed, many serological immunoassays are now in use. However, these many different assays make the standardization of test results difficult. Moreover, most published serological tests require venous blood sampling, which makes testing large numbers of people complex and costly. Here, we validate the GSP®/DELFIA® Anti-SARS-CoV-2 IgG kit using dried blood samples for high-throughput serosurveillance using standard quantitative measurements of anti-spike S1 IgG antibody concentrations. We then apply our validated assay to compare post-vaccination anti-SARS-CoV-2 S1 IgG levels from subjects who received a double dose of the AZD1222 vaccine with those vaccinated with a heterologous strategy, demonstrating how this assay is suitable for large-scale screening to achieve a clearer population immune picture.

Proteomics Approach Highlights Early Changes in Human Fibroblasts-Pancreatic Ductal Adenocarcinoma Cells Crosstalk.

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer mortality worldwide. Non-specific symptoms, lack of biomarkers in the early stages, and drug resistance due to the presence of a dense fibrous stroma all contribute to the poor outcome of this disease. The extracellular matrix secreted by activated fibroblasts contributes to the desmoplastic tumor microenvironment formation. Given the importance of fibroblast activation in PDAC pathology, it is critical to recognize the mechanisms involved in the transformation of normal fibroblasts in the early stages of tumorigenesis. To this aim, we first identified the proteins released from the pancreatic cancer cell line MIA-PaCa2 by proteomic analysis of their conditioned medium (CM). Second, normal fibroblasts were treated with MIA-PaCa2 CM for 24 h and 48 h and their proteostatic changes were detected by proteomics. Pathway analysis indicated that treated fibroblasts undergo changes compatible with the activation of migration, vasculogenesis, cellular homeostasis and metabolism of amino acids and reduced apoptosis. These biological activities are possibly regulated by ITGB3 and TGFB1/2 followed by SMAD3, STAT3 and BAG3 activation. In conclusion, this study sheds light on the crosstalk between PDAC cells and associated fibroblasts. Data are available via ProteomeXchange with identifier PXD030974.

Long persistence of severe acute respiratory syndrome coronavirus 2 swab positivity in a drowned corpse: a case report.

BACKGROUND: Since the beginning of the worldwide spread of severe acute respiratory syndrome coronavirus 2 to date, important knowledge has been obtained about the virus behavior in living subjects and on inanimate surfaces; however, there is still a lack of data on virus persistency on dead bodies and the risk of contagion from cadavers. CASE PRESENTATION: The present case shows the persistency of the severe acute respiratory syndrome coronavirus 2 viral genome in nasopharyngeal swabs performed on a drowned Caucasian man, aged 41 years old, who was completely asymptomatic when he was alive, up to 41 days after death. Specific real-time reverse transcriptase-polymerase chain reaction (TaqMan 2019-nCoV Assay Kit v2; Thermo Fisher Scientific, Italy and Realquality RQ-SARS-CoV-2, AB Analytical) was used to evaluate the swabs. CONCLUSIONS: This data reflect the importance of postmortem swabs in all autopsy cases, and not only in potential severe acute respiratory syndrome coronavirus 2-related death, and also highlight the necessity to evaluate virus positivity a long time after the moment of death, even if a low initial viral load was assessed.

Different Strategies for the Identification of SARS-CoV-2 Variants in the Laboratory Practice.

A considerable effort has been devoted in all countries to react to the COVID-19 pandemic by tracing infected individuals, containing the spread of the disease, identifying therapies, and producing and distributing vaccines. Currently, a significant concern is the appearance of variants of the virus that may frustrate these efforts by showing increased transmissibility, increased disease severity, reduced response to therapy or vaccines, and ability to escape diagnosis. All countries have therefore devoted a massive attempt to the identification and tracking of these variants, which requires a vast technological effort to sequence a large number of viral genomes. In this paper, we report our experience as one of the Italian laboratories involved in SARS-CoV-2 variant tracing. We summarize the different approaches used, and outline a potential model combining several techniques to increase tracing ability while at the same time minimizing costs.

High activity and low toxicity of a novel CD71-targeting nanotherapeutic named The-0504 on preclinical models of several human aggressive tumors.

BACKGROUND: Ferritin receptor (CD71) is an example of a very attractive cancer target, since it is highly expressed in virtually all tumor types, including metastatic loci. However, this target can be considered to be inaccessible to conventional target therapies, due to its presence in many healthy tissues. Here, we describe the preclinical evaluation of a tumor proteases-activatable human ferritin (HFt)-based drug carrier (The-0504) that is able to selectively deliver the wide-spectrum topoisomerase I inhibitor Genz-644282 to CD71-expressing tumors, preventing the limiting toxic effects associated with CD71-targeting therapies. METHODS: CD71 expression was evaluated using flow cytometry and immunohistochemistry techniques. The-0504 antiproliferative activity towards several cancer cell lines was assessed in vitro. The-0504 antitumor efficacy and survival benefit were evaluated in different human tumors, which had been grown either as xenografts or patient-derived xenografts in mice. The-0504 toxicology profile was investigated in multiple-cycle repeat-dose study in rodents. RESULTS: In vitro studies indicate that The-0504 is highly specific for CD71 expressing cells, and that there is a relationship between CD71 levels and The-0504 anticancer activity. In vivo treatments with The-0504 showed a remarkable efficacy, eradicating several human tumors of very diverse and aggressive histotypes, such as pancreas, liver and colorectal carcinomas, and triple-negative breast cancer. CONCLUSIONS: Durable disease-free survival, persistent antitumor responses after discontinuation of treatment and favorable toxicology profile make The-0504 an ideal candidate for clinical development as a novel, CD71-targeted, low-toxicity alternative to chemotherapy.

Normal breathing releases SARS-CoV-2 into the air.

This study tests the release of SARS-CoV-2 RNA into the air during normal breathing, without any sign of possible risk of contagion such as coughing, sneezing or talking. Five patients underwent oropharyngeal, nasopharyngeal and salivary swabs for real-time reverse transcriptase PCR (RT-PCR) detection of SARS-CoV-2 RNA. Direct SARS-CoV-2 release during normal breathing was also investigated by RT-PCR in air samples collected using a microbiological sampler. Viral RNA was detected in air at 1 cm from the mouth of patients whose oropharyngeal, nasopharyngeal and salivary swabs tested positive for SARS-CoV-2 RNA. In contrast, the viral RNA was not identified in the exhaled air from patients with oropharyngeal, nasopharyngeal and salivary swabs that tested negative. Contagion of SARS-CoV-2 is possible by being very close to the mouth of someone who is infected, asymptomatic and simply breathing.

Picture of the Favourable Immune Profile Induced by Anti-SARS-CoV-2 Vaccination.

COVID-19 pandemic has hit people's health, economy, and society worldwide. Great confidence in returning to normality has been placed in the vaccination campaign. The knowledge of individual immune profiles and the time required to achieve immunological protection is crucial to choose the best vaccination strategy. We compared anti-S1 antibody levels produced over time by BNT162b2 and AZD1222 vaccines and evaluated the induction of antigen-specific T-cells. A total of 2569 anti-SARS-CoV-2 IgG determination on dried blood spot samples were carried out, firstly in a cohort of 1181 individuals at random time-points, and subsequently, in an independent cohort of 88 vaccinated subjects, up to the seventeenth week from the first dose administration. Spike-specific T-cells were analysed in seronegative subjects between the two doses. AZD1222 induced lower anti-S1 IgG levels as compared to BNT162b2. Moreover, 40% of AZD1222 vaccinated subjects and 3% of BNT162b2 individuals resulted in seronegative during all the time-points, between the two doses. All these subjects developed antigen-specific T cells, already after the first dose. These results suggest that this test represents an excellent tool for a wide sero-surveillance. Both vaccines induce a favourable immune profile guaranteeing efficacy against severe adverse effects of SARS-CoV-2 infection, already after the first dose administration.

Engineered Human Nanoferritin Bearing the Drug Genz-644282 for Cancer Therapy.

Gastrointestinal tumors, including pancreatic and colorectal cancers, represent one of the greatest public health issues worldwide, leading to a million global deaths. Recent research demonstrated that the human heavy chain ferritin (HFt) can encapsulate different types of drugs in its cavity and can bind to its receptor, CD71, in several solid and hematological tumors, thus highlighting the potential use of ferritin for tumor-targeting therapies. Here, we describe the development and characterization of a novel nanomedicine based on the HFt that is named The-0504. In particular, this novel system is a nano-assembly comprising an engineered version of HFt that entraps about 80 molecules of a potent, wide-spectrum, non-camptothecin topoisomerase I inhibitor (Genz-644282). The-0504 can be produced by a standardized pre-industrial process as a pure and homogeneously formulated product with favourable lyophilization properties. The preliminary anticancer activity was evaluated in cultured cancer cells and in a mouse model of pancreatic cancer. Overall results reported here make The-0504 a candidate for further preclinical development against CD-71 expressing deadly tumors.

ABCC3 is a novel target for the treatment of pancreatic cancer.

Pancreatic Ductal Adenocarcinoma (PDAC) is a very aggressive disease, lacking effective therapeutic approaches and leaving PDAC patients with a poor prognosis. The life expectancy of PDAC patients has not experienced a significant change in the last few decades with a five-year survival rate of only 8%. To address this unmet need, novel pharmacological targets must be identified for clinical intervention. ATP Binding Cassette (ABC) transporters are frequently overexpressed in different cancer types and represent one of the major mechanisms responsible for chemoresistance. However, a more direct role for ABC transporters in tumorigenesis has not been widely investigated. Here, we show that ABCC3 (ABC Subfamily C Member 3; previously known as MRP3) is overexpressed in PDAC cell lines and also in clinical samples. We demonstrate that ABCC3 expression is regulated by mutant p53 via miR-34 and that the transporter drives PDAC progression via transport of the bioactive lipid lysophosphatidylinositol (LPI). Disruption of ABCC3 function either by genetic knockdown reduces pancreatic cancer cell growth in vitro and in vivo. Mechanistically, we demonstrate that knockdown of ABCC3 reduce cell proliferation by inhibition of STAT3 and HIF1α signalling pathways, previously been shown to be key regulators of PDAC progression. Collectively, our results identify ABCC3 as a novel and promising target in PDAC therapy.

Development of an anti-BAG3 humanized antibody for treatment of pancreatic cancer.

We have previously shown that secreted BAG3 is a potential target for the treatment of pancreatic ductal adenocarcinoma and that pancreatic tumor growth and metastatic dissemination can be reduced by treatment with an anti-BAG3 murine antibody. Here, we used complementarity-determining region (CDR) grafting to generate a humanized version of the anti-BAG3 antibody that may be further developed for possible clinical use. We show that the humanized anti-BAG3 antibody, named BAG3-H2L4, abrogates BAG3 binding to macrophages and subsequent release of IL-6. Furthermore, it specifically localizes into tumor tissues and significantly inhibits the growth of Mia PaCa-2 pancreatic cancer cell xenografts. We propose BAG3-H2L4 antibody as a potential clinical candidate for BAG3-targeted therapy in pancreatic cancer.

Pharmacological inhibition of ABCC3 slows tumour progression in animal models of pancreatic cancer.

BACKGROUND: Pancreatic Ductal Adenocarcinoma (PDAC) is an aggressive and lethal disease, lacking effective therapeutic approaches. Available therapies only marginally prolong patient survival and are frequently coupled with severe adverse events. It is therefore pivotal to investigate novel and safe pharmacological approaches. We have recently identified the ABC transporter, ABCC3, whose expression is dependent on mutation of TP53, as a novel target in PDAC. ABCC3-mediated regulation of PDAC cell proliferation and tumour growth in vivo was demonstrated and was shown to be conferred by upregulation of STAT3 signalling and regulation of apoptosis. METHODS: To verify the potential of ABCC3 as a pharmacological target, a small molecule inhibitor of ABCC3, referred to here as MCI-715, was designed. In vitro assays were performed to assess the effects of ABCC3 inhibition on anchorage-dependent and anchorage-independent PDAC cell growth. The impact of ABCC3 inhibition on specific signalling pathways was verified by Western blotting. The potential of targeting ABCC3 with MCI-715 to counteract PDAC progression was additionally tested in several animal models of PDAC, including xenograft mouse models and transgenic mouse model of PDAC. RESULTS: Using both mouse models and human cell lines of PDAC, we show that the pharmacological inhibition of ABCC3 significantly decreased PDAC cell proliferation and clonal expansion in vitro and in vivo, remarkably slowing tumour growth in mice xenografts and patient-derived xenografts and increasing the survival rate in a transgenic mouse model. Furthermore, we show that stromal cells in pancreatic tumours, which actively participate in PDAC progression, are enriched for ABCC3, and that its inhibition may contribute to stroma reprogramming. CONCLUSIONS: Our results indicate that ABCC3 inhibition with MCI-715 demonstrated strong antitumor activity and is well tolerated, which leads us to conclude that ABCC3 inhibition is a novel and promising therapeutic strategy for a considerable cohort of patients with pancreatic cancer.