Clinically relevant treatment of PDX models reveals patterns of neuroblastoma chemoresistance.

Chemotherapy resistance and relapses are common in high-risk neuroblastoma (NB). Here, we developed a clinically relevant in vivo treatment protocol mimicking the first-line five-chemotherapy treatment regimen of high-risk NB and applied this protocol to mice with MYCN-amplified NB patient-derived xenografts (PDXs). Genomic and transcriptomic analyses were used to reveal NB chemoresistance mechanisms. Intrinsic resistance was associated with high genetic diversity and an embryonic phenotype. Relapsed NB with acquired resistance showed a decreased adrenergic phenotype and an enhanced immature mesenchymal-like phenotype, resembling multipotent Schwann cell precursors. NBs with a favorable treatment response presented a lineage-committed adrenergic phenotype similar to normal neuroblasts. Novel integrated phenotypic gene signatures reflected treatment response and patient prognosis. NB organoids established from relapsed PDX tumors retained drug resistance, tumorigenicity, and transcriptional cell states. This work sheds light on the mechanisms of NB chemotherapy response and emphasizes the importance of transcriptional cell states in chemoresistance.

Golden and Silver-Golden Chitosan Hydrogels and Fabrics Modified with Golden Chitosan Hydrogels.

Golden and silver-golden chitosan hydrogels and hydrogel-modified textiles of potential biomedical applications are investigated in this work. The hydrogels are formed by reactions of chitosan with HAuCl4·xH2O. For above the critical concentration of chitosan (c*), chitosan-Au hydrogels were prepared. For chitosan concentrations lower than c*, chitosan-Au nano- and microgels were formed. To characterise chitosan-Au structures, sol-gel analysis, UV-Vis spectrophotometry and dynamic light scattering were performed. Au concentration in the hydrogels was determined by the flame atomic absorption spectrophotometry. Colloidal chitosan-Au solutions were used for the modification of fabrics. The Au content in the modified fabrics was quantified by inductively coupled plasma mass spectrometry technique. Scanning electron microscopy with energy dispersion X-ray spectrometer was used to analyse the samples. Reflectance spectrophotometry was applied to examine the colour of the fabrics. The formation of chitosan-Au-Ag hydrogels by the competitive reaction of Au and Ag ions with the chitosan macromolecules is reported.

Patient-derived models: Advanced tools for precision medicine in neuroblastoma.

Neuroblastoma is a childhood cancer derived from the sympathetic nervous system. High-risk neuroblastoma patients have a poor overall survival and account for ~15% of childhood cancer deaths. There is thus a need for clinically relevant and authentic models of neuroblastoma that closely resemble the human disease to further interrogate underlying mechanisms and to develop novel therapeutic strategies. Here we review recent developments in patient-derived neuroblastoma xenograft models and in vitro cultures. These models can be used to decipher mechanisms of metastasis and treatment resistance, for drug screening, and preclinical drug testing. Patient-derived neuroblastoma models may also provide useful information about clonal evolution, phenotypic plasticity, and cell states in relation to neuroblastoma progression. We summarize current opportunities for, but also barriers to, future model development and application. Integration of patient-derived models with patient data holds promise for the development of precision medicine treatment strategies for children with high-risk neuroblastoma.

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.

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.

Pancreatic cancer tumorspheres are cancer stem-like cells with increased chemoresistance and reduced metabolic potential.

Cancer stem cells are a population of slow-cycling cells within the tumour bulk, with self-renewal capacity that attracts interest as a therapeutic target. In highly heterogeneous tumours, like pancreatic ductal adenocarcinoma (PDAC) however, the characterisation of cancer stem cells has led to controversial results due to the lack of consensus on specific markers. Here we investigated the characteristics of a population of pancreatic cancer tumorspheres derived from different human pancreatic cancer cell lines and a primary line from a genetically engineered KPC mouse model, using flow cytometry and western blotting to analyse surface and stemness markers. We analysed tumorspheres tumorigenic potential using anchorage-independent soft agar assay as well as their metabolic plasticity and chemoresistance. Pancreatic cancer tumorspheres display a heterogeneous pattern of surface and stemness markers, nevertheless they are characterised by an increased tumorigenic potential and higher chemoresistance. In addition, we have shown that pancreatic cancer tumorspheres have a unique metabolic profile with reduced metabolic potential. Together our results indicate that, despite the heterogeneity characterising pancreatic cancer tumorspheres, we can identify a functional vulnerability that represents a window for pharmacological intervention and development of novel therapeutic strategies.

ABC transporters as cancer drivers: Potential functions in cancer development.

BACKGROUND: ABC transporters have attracted considerable attention for their function as drug transporters in a broad range of tumours and are therefore considered as major players in cancer chemoresistance. However, less attention has been focused on their potential role as active players in cancer development and progression. SCOPE OF REVIEW: This review presents the evidence suggesting that ABC transporters might have a more active role in cancer other than the well known involvement in multidrug resistance and discusses the potential strategies to target each ABC transporter for a specific tumour setting. MAJOR CONCLUSIONS: Emerging evidence suggests that ABC transporters are able to transport bioactive molecules capable of playing key roles in tumour development. Characterization of the effects of these transporters in specific cancer settings opens the possibility for the development of personalized treatments. GENERAL SIGNIFICANCE: A more targeted approach of ABC transporters should be implemented that considers which specific transporter is playing a major role in a particular tumour setting in order to achieve a more successful outcome for ABC transporters inhibitors in cancer therapy.

ATP-binding cassette transporters in progression and clinical outcome of pancreatic cancer: What is the way forward?

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases and is characterized by high chemoresistance, leading to the lack of effective therapeutic approaches and grim prognosis. Despite increasing understanding of the mechanisms of chemoresistance in cancer and the role of ATP-binding cassette (ABC) transporters in this resistance, the therapeutic potential of their pharmacological inhibition has not been successfully exploited yet. In spite of the discovery of potent pharmacological modulators of ABC transporters, the results obtained in clinical trials have been so far disappointing, with high toxicity levels impairing their successful administration to the patients. Critically, although ABC transporters have been mostly studied for their involvement in development of multidrug resistance (MDR), in recent years the contribution of ABC transporters to cancer initiation and progression has emerged as an important area of research, the understanding of which could significantly influence the development of more specific and efficient therapies. In this review, we explore the role of ABC transporters in the development and progression of malignancies, with focus on PDAC. Their established involvement in development of MDR will be also presented. Moreover, an emerging role for ABC transporters as prognostic tools for patients' survival will be discussed, demonstrating the therapeutic potential of ABC transporters in cancer therapy.

Molecular and cellular mechanisms of chemoresistance in pancreatic cancer.

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most chemoresistant cancers, and current therapies targeting cancer-associated molecular pathways have not given satisfactory results, owing in part to rapid upregulation of alternative compensatory pathways. Most of the available treatments are palliative, focussing on improving the quality of life. At present, available options are surgery, embolization, radiation, chemotherapy, immunotherapy and use of other more targeted drugs. In this review, we describe the cellular and molecular effects of current chemotherapy drugs such as gemcitabine, FOLFIRINOX (5-fluorouracil [5-FU], oxaliplatin, irinotecan, and leucovorin) and ABRAXANE (nab-Paclitaxel), which have shown a survival benefit, although modest, for pancreatic cancer patients. Nevertheless, gemcitabine remains the standard first-line option for advanced-stage pancreatic cancer patients and, as resistance to the drug has attracted an increasing scientific interest, we deliberate on the main intracellular processes and proteins vital in acquired chemoresistance to gemcitabine. Lastly, our review examines various microenvironmental factors capable of instigating PDAC to develop resistance to chemotherapeutic drugs.

Pancreatic Ductal Adenocarcinoma: Current and Evolving Therapies.

Pancreatic ductal adenocarcinoma (PDAC), which constitutes 90% of pancreatic cancers, is the fourth leading cause of cancer-related deaths in the world. Due to the broad heterogeneity of genetic mutations and dense stromal environment, PDAC belongs to one of the most chemoresistant cancers. Most of the available treatments are palliative, with the objective of relieving disease-related symptoms and prolonging survival. Currently, available therapeutic options are surgery, radiation, chemotherapy, immunotherapy, and use of targeted drugs. However, thus far, therapies targeting cancer-associated molecular pathways have not given satisfactory results; this is due in part to the rapid upregulation of compensatory alternative pathways as well as dense desmoplastic reaction. In this review, we summarize currently available therapies and clinical trials, directed towards a plethora of pathways and components dysregulated during PDAC carcinogenesis. Emerging trends towards targeted therapies as the most promising approach will also be discussed.

Class II Phosphoinositide 3-Kinases as Novel Drug Targets.

The phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases central to regulating a wide range of important intracellular processes. Despite the vast knowledge around class I PI3Ks, the class II PI3Ks have been neglected, seemingly only due to the chronology of their discovery. Here we focus on the cellular functions of the three class II PI3K isoforms, PI3KC2α, PI3KC2ß, and PI3KC2γ, in different cell systems and underline the emerging importance of these enzymes in different physiological and pathological contexts. We provide an overview on the current development of class II PI3 kinase inhibitors and outline the potential use for such inhibitors. The field is in its infancy as compared to their class I counterparts. Nevertheless, recent advances in understanding the roles of class II PI3 kinases in different pathological contexts is leading to an increased interest in the development of specific inhibitors that can provide potential novel pharmacological tools.