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In living cells, some reactions can be conducted by more than one enzyme and sometimes it is difficult to establish which enzyme is responsible. Such is the case with proteins from the TET family, capable of converting 5-methyl-2'-deoxycytidine (5- m d C ) in DNA to 5-(hydroxymethyl)-2'-deoxycytidine (5- h m d C ) and further to 5-formyl-2'-deoxycytidine (5- f d C ) and 5-carboxy-2'-deoxycytidine (5- c a d C ). The estimation of the efficiency of particular TETs in particular oxidative reactions and different cell types is important but experimentally difficult. Here, we propose an approach with mathematical modeling in which methylation and known deoxycytidine modification pathways are presented by 343 possible model versions with assumed different combinations of TET1, 2, and 3 activities in different pathways. Model parameters were calculated on the basis of 5- m d C , 5- h m d C , 5- f d C , 5- c a d C , and 5- h m d U levels experimentally assessed in five human cultured cell lines and previously published. Selection of the model versions that give in simulations the best average fit to experimental data suggested that not all TET proteins participate in all modification reactions and that TET3 activity may be especially important in the reaction of 5- f d C removal. [ABSTRACT FROM AUTHOR]

Ribonucleotide reductases (RNRs) are essential enzymes that catalyze the de novo transformation of nucleoside 5- di(tri)phosphates [ND(T)Ps, where N is A, U, C, or G] to their corresponding deoxynucleotides. Despite the diversity of factors required for function and the low sequence conservation across RNRs, a unifying apparatus consolidating RNR activity is explored. We combine aspects of the protein subunit simplicity of class II RNR with a modified version of Escherichia coli class la photoRNRs that initiate radical chemistry with light to engineer a mimic of a class II enzyme. The design of this RNR involves fusing a truncated form of the active site containing α subunit with the functionally important C- terminal tail of the radical- generating β subunit to render a chimeric RNR. Inspired by a recent cryo- EM structure, a [Re] photooxidant is located adjacent to Y356[β], which is an essential component of the radical transport pathway in class I RNRs. Combination of this RNR photochimera with cytidine diphosphate (CDP), adenosine triphosphate (ATP), and light resulted in the generation of Y356• along with production of deoxycytidine diphosphate (dCDP) and cytosine. The photoproducts reflect an active site chemistry consistent with both the consensus mechanism of RNR and chemistry observed when RNR is inactivated by mechanism- based inhibitors in the active site. The enzymatic activity of the RNR photochimera in the absence of any β metallocofactor highlights the adaptability of the 10- stranded αβ barrel finger loop to support deoxynucleotide formation and accommodate the design of engineered RNRs. [ABSTRACT FROM AUTHOR]

Summary: Background: DNA polymerase gamma (POLG)-related disorders are a group of rare neurodegenerative mitochondrial diseases caused by pathogenic variants in POLG, the gene encoding POLG. Patients may experience a range of signs and symptoms, including seizures, vision loss, myopathy, neuropathy, developmental impairment or regression, and liver failure. The diseases follow a progressive, degenerative course, with most affected individuals dying within 3 months–12 years of diagnosis. At present, there are no effective treatments for POLG-related disorders. Methods: In this study we report the interim 6-month data from a long term open-label, single arm phase 2 trial, in which we assessed the safety and efficacy of combination therapy with deoxycytidine and deoxythymidine (dC/dT) in children with POLG-related disorders. dC/dT was given enterally in powder form, dissolved in water. The primary outcome measures included Newcastle Mitochondrial Disease Scale (NMDS) score, serum growth differentiation factor 15 (GDF-15; a biomarker of mitochondrial dysfunction), electroencephalography (EEG), seizure diary, and blood and urine tests to assess end organ and mitochondrial function. Secondary outcome measures included recording of all adverse events to evaluate the safety of the intervention. The trial is registered with ClinicalTrials.gov, NCT04802707 (https://clinicaltrials.gov/ct2/show/NCT04802707). Data were collected from 14 October, 2021 to 13 December, 2023. Findings: We present 6-month interim data from the first ten people with POLG-related disorders enrolled in the trial, six with Alpers-Huttenlocher syndrome, two with ataxia-neuropathy spectrum, and two who do not fit into a classical POLG-related phenotype. During the 6 months of treatment, NMDS score improved from a mean of 27.3 at baseline to 20.7 at 6 months (estimated difference 6.0; 95% CI 2.5–∞). GDF-15 values remained stable or decreased in all patients; the mean decreased from 1031 pg/ml to 729 pg/ml (estimated difference 200; 95% CI 12–∞). 8/10 patients had abnormal baseline EEG; improvement in EEG was seen in 5 of these 8. There were no significant changes in other blood and urine testing. Regarding adverse events, two patients experienced diarrhea that spontaneously resolved. Interpretation: dC/dT is a promising treatment option for people with POLG-related disorders. Further research is needed to assess the long-term safety and efficacy in POLG-related disorders, as well as safety and efficacy in other mitochondrial DNA depletion disorders. Funding: This study was primarily funded by the Liam Foundation, with additional funding from the Savoy Foundation, Grand Défi Pierre Lavoie Foundation, and Fonds de Recherche du Québec - Santé.

Host-directed therapy (HDT) is an emerging approach to overcome antimicrobial resistance in pathogenic microorganisms. Specifically, HDT targets host-encoded factors required for pathogen replication and survival without interfering with microbial growth or metabolism, thereby eliminating the risk of resistance development. By applying HDT and a drug repurposing approach, we demonstrate that (R)-DI-87, a clinical-stage anticancer drug and potent inhibitor of mammalian deoxycytidine kinase (dCK), mitigates Staphylococcus aureus abscess formation in organ tissues upon invasive bloodstream infection. Mechanistically, (R)-DI- 87 shields phagocytes from staphylococcal death-effector deoxyribonucleosides that target dCK and the mammalian purine salvage pathway-apoptosis axis. In this manner, (R)-DI- 87- mediated protection of immune cells amplifies macrophage infiltration into deep-seated abscesses, a phenomenon coupled with enhanced pathogen control, ameliorated immunopathology, and reduced disease severity. Thus, pharmaceutical blockade of dCK represents an advanced anti-infective intervention strategy against which staphylococci cannot develop resistance and may help to fight fatal infectious diseases in hospitalized patients. [ABSTRACT FROM AUTHOR]

Bladder cancer (BCa) research relying on Omics approaches has increased over the last few decades, improving the understanding of BCa pathology and contributing to a better molecular classification of BCa subtypes. To gain further insight into the molecular profile underlying the development of BCa, a systematic literature search was performed in PubMed until November 2023, following the PRISMA guidelines. This search enabled the identification of 25 experimental studies using mass spectrometry or nuclear magnetic resonance-based approaches to characterize the metabolite signature associated with BCa. A total of 1562 metabolites were identified to be altered by BCa in different types of samples. Urine samples displayed a higher likelihood of containing metabolites that are also present in bladder tumor tissue and cell line cultures. The data from these comparisons suggest that increased concentrations of L-isoleucine, L-carnitine, oleamide, palmitamide, arachidonic acid and glycoursodeoxycholic acid and decreased content of deoxycytidine, 5-aminolevulinic acid and pantothenic acid should be considered components of a BCa metabolome signature. Overall, molecular profiling of biological samples by metabolomics is a promising approach to identifying potential biomarkers for early diagnosis of different BCa subtypes. However, future studies are needed to understand its biological significance in the context of BCa and to validate its clinical application. [ABSTRACT FROM AUTHOR]

The main challenge in using gemcitabine, a nucleoside analogue anti-cancer, includes resistance of some patients to this compound due to the genetic mutations on deoxycytidine kinase (dCK) that are found in a fraction of the human population. Here, we investigated the dynamics behavior and ligand binding properties of the wild type (WT) dCK and its characterized double mutant using a combination of bioinformatics tools and molecular dynamics (MD) simulation studies. Root-mean-square deviation (RMSD) values of the WT and mutant enzyme in complex with both ligands (deoxycytidine/gemcitabine) demonstrated that the WT enzyme forms a more stable complex with gemcitabine, as compared with its natural ligand (deoxycytidine). However, the stability of the double mutant-deoxycytidine complex is greater, when compared with gemcitabine. It was also found that Arg131 as a critical residue can affect the binding pattern of the enzyme to ligands in a manner that the WT enzyme can interact with both ligands, while, the mutant enzyme cannot establish efficient interaction with gemcitabine, and shows high affinity to deoxycytidine. These data together indicate that gemcitabine can interact with the WT enzyme in a competitive manner, while double mutant can be considered as a resistant variant against gemcitabine. The interaction of anti-cancer gemcitabine with deoxycytidine kinase (dCK) was compared with its natural analogue; deoxycytidine. The dynamics behavior of the representative drug-resistant mutant of deoxycytidine kinase (dCK) was investigated in comparison with the wild type enzyme. The results of this study explain the mechanism of resistance of resistant variant against gemcitabine. [ABSTRACT FROM AUTHOR]

Rationale: Cytosine and its conjugates are prone to form protonated, triply‐bonded dimers. Therefore, the nucleic‐acid cytosine‐rich sequence forms the four‐stranded noncanonical secondary structure known as the intercalated motif (i‐motif). This process has resulted in studies on cytosine protonated dimers. This communication focuses on the protonated dimers of cytosine and its nucleoside using the survival yield (SY) method and quantum mechanics calculations. Methods: To obtain the precursor ion fragmentation curve, the plot of SY against Ecomδ, the product ion spectra of the protonated dimers were obtained using a Waters/Micromass Q‐TOF Premier mass spectrometer. Quantum mechanics calculations were performed using GAUSSIAN 16, and full geometry optimizations and energy calculations were performed within the density functional theory framework at B3LYP/6‐31G(d,p). Results: The precursor ion fragmentation curve allowed the rating of the gas‐phase stabilities of the analyzed protonated dimers. Substitution of sugar moiety at N1 cytosine atom decreased the gas‐phase stabilities of the protonated dimers. The deoxycytidine dimer was found to be more stable than the cytidine dimer and cytidine–deoxycytidine dimer. Quantum chemical calculations indicated that cytosine aminohydroxy tautomer may be involved in the formation of protonated cytosine–cytosine nucleoside dimers but not in the formation of cytosine dimers. Conclusions: The results obtained for nucleoside dimers indicated that the SY method may reflect the i‐motif stabilities observed under physiological conditions. Therefore, the analysis of other protonated dimers of variously substituted cytosine–cytosine nucleoside using the SY method may be important to study the effect of cytosine substitution on the i‐motif stabilities. Cytosine tautomer containing C2‐OH... N(2H)‐C4 moiety may be involved in the formation of protonated cytosine–cytosine nucleoside dimers. [ABSTRACT FROM AUTHOR]

The self-digestive solution (SDS) of the biocontrol bacterium Lysobacter enzymogenes LE16 shows strong antagonistic activities against multiple soil-borne phytopathogens but the positive evidence of this bacterium against plant foliar disease is still scanty. Thus, laboratory, greenhouse, and field experiments were carried out to estimate the efficacies of SDS, S-SDS (stored at room temperature for 12 months), and H-SDS (heated at 100°C for 30 min) against plant powdery mildew. This bacterium produced hydrolases (phosphatase, protease, lysozyme, chitinase, and β-1,3-glucanase) that degrade pathogen cell components and siderophores that compete for iron with phytopathogens. The top five antimicrobial metabolites identified in SDS were pyroglutamic acid, deoxycytidine, pyrrole-2-carboxylic acid, 13-oxo-9,11-tridecadienoic acid, and 3'-amino-3'-deoxythimidine. Among them, pyroglutamic acid may play a vital role in powdery mildew control. As a result, SDS, S-SDS, and H-SDS strongly inhibited the conidial germination of Erysiphe cichoracearum and Sphaerotheca fuliginea. The application of SDS significantly increased the activity of antioxidant enzymes in crop leaves and effectively controlled tobacco and cucumber powdery mildew in the greenhouse and the field. Therefore, L. enzymogenes LE16 can effectively control powdery mildew. The underlying mechanisms may be attributed to the induction of plant systemic resistance and the production of antifungal substances. [ABSTRACT FROM AUTHOR]

The de novo synthesis of deoxythymidine triphosphate uses several pathways: gram-negative bacteria use deoxycytidine triphosphate deaminase to convert deoxycytidine triphosphate into deoxyuridine triphosphate, whereas eukaryotes and gram-positive bacteria instead use deoxycytidine monophosphate deaminase to transform deoxycytidine monophosphate to deoxyuridine monophosphate. It is then unusual that in addition to deoxycytidine monophosphate deaminases, the eukaryote Dictyostelium discoideum has 2 deoxycytidine triphosphate deaminases (Dcd1Dicty and Dcd2Dicty). Expression of either DcdDicty can fully rescue the slow growth of an Escherichia coli dcd knockout. Both DcdDicty mitigate the hydroxyurea sensitivity of a Schizosaccharomyces pombe deoxycytidine monophosphate deaminase knockout. Phylogenies show that Dcd1Dicty homologs may have entered the common ancestor of the eukaryotic groups of Amoebozoa, Obazoa, Metamonada, and Discoba through an ancient horizontal gene transfer from a prokaryote or an ancient endosymbiotic gene transfer from a mitochondrion, followed by horizontal gene transfer from Amoebozoa to several other unrelated groups of eukaryotes. In contrast, the Dcd2Dicty homologs were a separate horizontal gene transfer from a prokaryote or a virus into either Amoebozoa or Rhizaria, followed by a horizontal gene transfer between them. ThyXDicty, the D. discoideum thymidylate synthase, another enzyme of the deoxythymidine triphosphate biosynthesis pathway, was suggested previously to be acquired from the ancestral mitochondria or by horizontal gene transfer from alpha-proteobacteria. ThyXDicty can fully rescue the E. coli thymidylate synthase knockout, and we establish that it was obtained by the common ancestor of social amoebae not from mitochondria but from a bacterium. We propose horizontal gene transfer and endosymbiotic gene transfer contributed to the enzyme diversity of the deoxythymidine triphosphate synthesis pathway in most social amoebae, many Amoebozoa, and other eukaryotes. [ABSTRACT FROM AUTHOR]

Deoxycytidine analogues (dCas) are widely used for the treatment of malignant diseases. They are commonly inactivated by cytidine deaminase (CDD), or by deoxycytidine monophosphate deaminase (dCMP deaminase). Additional metabolic pathways, such as phosphorylation, can substantially contribute to their (in)activation. Here, a new technique for the analysis of these pathways in cells is described. It is based on the use of 5-ethynyl 2′-deoxycytidine (EdC) and its conversion to 5-ethynyl 2′-deoxyuridine (EdU). Its use was tested for the estimation of the role of CDD and dCMP deaminase in five cancer and four non-cancer cell lines. The technique provides the possibility to address the aggregated impact of cytidine transporters, CDD, dCMP deaminase, and deoxycytidine kinase on EdC metabolism. Using this technique, we developed a quick and cheap method for the identification of cell lines exhibiting a lack of CDD activity. The data showed that in contrast to the cancer cells, all the non-cancer cells used in the study exhibited low, if any, CDD content and their cytidine deaminase activity can be exclusively attributed to dCMP deaminase. The technique also confirmed the importance of deoxycytidine kinase for dCas metabolism and indicated that dCMP deaminase can be fundamental in dCas deamination as well as CDD. Moreover, the described technique provides the possibility to perform the simultaneous testing of cytotoxicity and DNA replication activity. [ABSTRACT FROM AUTHOR]

We present a comprehensive multi-omic analysis of the EPISTOP prospective clinical trial of early intervention with vigabatrin for pre-symptomatic epilepsy treatment in Tuberous Sclerosis Complex (TSC), in which 93 infants with TSC were followed from birth to age 2 years, seeking biomarkers of epilepsy development. Vigabatrin had profound effects on many metabolites, increasing serum deoxycytidine monophosphate (dCMP) levels 52-fold. Most serum proteins and metabolites, and blood RNA species showed significant change with age. Thirty-nine proteins, metabolites, and genes showed significant differences between age-matched control and TSC infants. Six also showed a progressive difference in expression between control, TSC without epilepsy, and TSC with epilepsy groups. A multivariate approach using enrollment samples identified multiple 3-variable predictors of epilepsy, with the best having a positive predictive value of 0.987. This rich dataset will enable further discovery and analysis of developmental effects, and associations with seizure development in TSC. A comprehensive multi-omic analysis of the EPISTOP trial for Tuberous Sclerosis Complex (TSC). was performed. Here, authors show many differences in serum proteins and metabolites, and blood RNA species, including associations with seizure development. [ABSTRACT FROM AUTHOR]

Introduction: Since the beginning of the SARS-CoV-2 pandemic in December 2019 multiple metabolomics studies have proposed predictive biomarkers of infection severity and outcome. Whilst some trends have emerged, the findings remain intangible and uninformative when it comes to new patients. Objectives: In this study, we accurately quantitate a subset of compounds in patient serum that were found predictive of severity and outcome. Methods: A targeted LC–MS method was used in 46 control and 95 acute COVID-19 patient samples to quantitate the selected metabolites. These compounds included tryptophan and its degradation products kynurenine and kynurenic acid (reflective of immune response), butyrylcarnitine and its isomer (reflective of energy metabolism) and finally 3′,4′-didehydro-3′-deoxycytidine, a deoxycytidine analogue, (reflective of host viral defence response). We subsequently examine changes in those markers by disease severity and outcome relative to those of control patients' levels. Results & conclusion: Finally, we demonstrate the added value of the kynurenic acid/tryptophan ratio for severity and outcome prediction and highlight the viral detection potential of ddhC. [ABSTRACT FROM AUTHOR]

Approximately 20% of patients with ulcerative colitis (UC) develop acute severe UC (ASUC), for which intravenous systemic steroid therapy and possibly infliximab-based rescue therapy are generally imposed. However, there are no significant guideline recommendations on ASUC regarding vedolizumab as an alternative in this setting. A case report was presented where a patient with steroid-dependent UC developed ASUC induced by second-line chemotherapy. Treatment with intravenous methylprednisolone was imposed, but there was no reduction in bowel movements in the days following admission. Rescue therapy with infliximab was contraindicated because of the oncologic history. Surgical consultation, contraindicated colectomy, and administration of vedolizumab 300 mg were initiated. After infusion with vedolizumab, there was a significant reduction in bowel movements starting the day after infusion until normalisation of bowel movements within three days and the concomitant normalisation of inflammatory indices. The patient is currently in clinical remission, on therapy with vedolizumab 108 mg subcutaneously every two weeks, and is in oncologic follow-up for pulmonary neoplasm. This case highlights the novel potential of vedolizumab as a possible rescue therapy in ASUC, especially in special populations, where it may offer a better safety profile. Although cyclosporine and infliximab still represent the mainstays of salvage therapy for steroid-refractory ASUC, new therapeutic agents may also be effective, such as vedolizumab, ustekinumab, and anti-Janus kinase agents. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is an autoimmune disease driven by lymphocyte activation against myelin autoantigens in the central nervous system leading to demyelination and neurodegeneration. The deoxyribonucleoside salvage pathway with the rate‐limiting enzyme deoxycytidine kinase (dCK) captures extracellular deoxyribonucleosides for use in intracellular deoxyribonucleotide metabolism. Previous studies have shown that deoxyribonucleoside salvage activity is enriched in lymphocytes and required for early lymphocyte development. However, specific roles for the deoxyribonucleoside salvage pathway and dCK in autoimmune diseases such as MS are unknown. Here we demonstrate that dCK activity is necessary for the development of clinical symptoms in the MOG35–55 and MOG1–125 experimental autoimmune encephalomyelitis (EAE) mouse models of MS. During EAE disease, deoxyribonucleoside salvage activity is elevated in the spleen and lymph nodes. Targeting dCK with the small molecule dCK inhibitor TRE‐515 limits disease severity when treatments are started at disease induction or when symptoms first appear. EAE mice treated with TRE‐515 have significantly fewer infiltrating leukocytes in the spinal cord, and TRE‐515 blocks activation‐induced B and T cell proliferation and MOG35–55‐specific T cell expansion without affecting innate immune cells or naïve T and B cell populations. Our results demonstrate that targeting dCK limits symptoms in EAE mice and suggest that dCK activity is required for MOG35–55‐specific lymphocyte activation‐induced proliferation. [ABSTRACT FROM AUTHOR]

Simple Summary: Colorectal cancer is the third most common cancer worldwide. The treatment of the advanced stages is based on poly-chemotherapies, including oxaliplatin. However, the development of resistance to chemotherapy is observed in 50% of cases, leading to treatment failures. A better understanding of the resistance mechanisms is therefore crucial to improve treatment efficiency and patient survival. In our previous work, showed that ROS production and the p38 MAPK pathway were strongly involved in resistance to oxaliplatin. In this study, we tested several chemotherapies and observed that only gemcitabine efficiently treated oxaliplatin-resistant cancer cells. Indeed, gemcitabine was able to induce apoptosis by inhibiting both the Akt and p38 MAPK pathways. Taken together, our results show that gemcitabine could be an interesting therapeutic option for patients with oxaliplatin-resistant tumors. Resistance to treatments is one of the leading causes of cancer therapy failure. Oxaliplatin is a standard chemotherapy used to treat metastatic colorectal cancer. However, its efficacy is greatly reduced by the development of resistances. In a previous study, we deciphered the mechanisms leading to oxaliplatin resistance and highlighted the roles played by ROS production and the p38 MAPK pathway in this phenomenon. In this report, we studied the effects of different chemotherapy molecules on our oxaliplatin-resistant cells to identify alternative treatments. Among all the studied molecules, gemcitabine was the only one to present a major cytotoxic effect on oxaliplatin-resistant cancer cells both in vivo and in vitro. However, the combination of oxaliplatin and gemcitabine did not present any major interest. Indeed, the study of combination efficiency using Chou and Talalay's method showed no synergy between oxaliplatin and gemcitabine. Using PamGene technology to decipher gemcitabine's effects on oxaliplatin-resistant cells, we were able to show that gemcitabine counteracts chemoresistance by strongly inhibiting the Akt and src/p38 MAPK pathways, leading to apoptosis induction and cell death. In view of these results, gemcitabine could be an interesting alternative therapy for patients with colorectal cancer not responding to oxaliplatin-based protocols such as FOLFOX. [ABSTRACT FROM AUTHOR]

Background: This randomised phase II/III trial aimed to determine whether perioperative chemotherapy with gemcitabine plus docetaxel (GD) is non-inferior to the standard Adriamycin plus ifosfamide (AI) in terms of overall survival (OS) in patients with soft tissue sarcoma (STS).Methods: Patients with localised high-risk STS in the extremities or trunk were randomised to receive AI or GD. The treatments were repeated for three preoperative and two postoperative courses. The primary endpoint was OS.Results: Among 143 enrolled patients who received AI (70 patients) compared to GD (73 patients), the estimated 3-year OS was 91.4% for AI and 79.2% for GD (hazard ratio 2.55, 95% confidence interval: 0.80-8.14, P = 0.78), exceeding the prespecified non-inferiority margin in the second interim analysis. The estimated 3-year progression-free survival was 79.1% for AI and 59.1% for GD. The most common Grade 3-4 adverse events in the preoperative period were neutropenia (88.4%), anaemia (49.3%), and febrile neutropenia (36.2%) for AI and neutropenia (79.5%) and febrile neutropenia (17.8%) for GD.Conclusions: Although GD had relatively mild toxicity, the regimen-as administered in this study-should not be considered a standard treatment of perioperative chemotherapy for high-risk STS in the extremities and trunk.Clinical Trial Registration: jRCTs031180003. [ABSTRACT FROM AUTHOR]

Background: Gemcitabine and cisplatin has limited benefit as treatment for advanced biliary tract cancer (BTC). The addition of an anti-programmed death receptor (PD-1)/PD-ligand (L1) antibody to either systemic chemotherapy or anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) antibody has shown benefit in multiple solid tumors.Methods: In this phase 2 trial, patients 18 years or older with advanced BTC without prior systemic therapy and Eastern Cooperative Oncology Group Performance Status 0-1 were randomized across six academic centers. Patients in Arm A received nivolumab (360 mg) on day 1 along with gemcitabine and cisplatin on days 1 and 8 every 3 weeks for 6 months followed by nivolumab (240 mg) every 2 weeks. Patients in Arm B received nivolumab (240 mg) every 2 weeks and ipilimumab (1 mg/kg) every 6 weeks.Results: Of 75 randomized patients, 68 received therapy (Arm A = 35, Arm B = 33); 51.5% women with a median age of 62.5 years. The observed primary outcome of 6-month progression-free survival (PFS) rates in the evaluable population was 59.4% in Arm A and 21.2% in Arm B. The median PFS and overall survival (OS) in Arm A were 6.6 and 10.6 months, and in Arm B 3.9 and 8.2 months, respectively, in patients who received any treatment. The most common treatment-related grade 3 or higher hematologic adverse event was neutropenia in 34.3% (Arm A) and nonhematologic adverse events were fatigue (8.6% Arm A) and elevated transaminases (9.1% Arm B).Conclusions: The addition of nivolumab to chemotherapy or ipilimumab did not improve 6-month PFS. Although median OS was less than 12 months in both arms, the high OS rate at 2 years in Arm A suggests benefit in a small cohort of patients. [ABSTRACT FROM AUTHOR]

Altogether six tautomers of cytosine and three tautomers of cytidine and deoxycytidine are studied theoretically in the gas phase and in a microhydrated environment. Their structures are optimized at MP2/6–31 + G(d,p) level. The relative energies of the isolated and the hydrated tautomers included the correction to higher correlation energy terms evaluated at the SCS‐MP2, MP4, and CCSD(T) levels. The free energies at 298 K and higher temperatures are based on the above‐mentioned relative energies and temperature‐dependent enthalpy terms and entropies evaluated at the MP2/6–31 + G(d,p) level. Theoretical predictions for the coexistence of five species for cytosine in the gas phase (canonical, trans‐ and cis‐enol‐amino, trans‐ and cis‐imino‐oxo forms) fully agree with recent experimental results. Five‐hydrated cytosine tautomeric forms of are investigated at CPCM/SCS‐MP2/6–31 + G(d,p) level to evaluate the interconversion barriers between them and to explain the coexistence, experimentally proven, of two amino‐oxo and one imino‐oxo tautomers of cytosine in aqueous solution. The presence of coordinated water molecules acting as a catalyst make the tautomerization processes quite easier. It appeared clear from the obtained data that the influence of the hydrogen‐bonded water molecules as well as the introduction of solvent effects in reducing the height of the tautomerization barriers for these five‐hydrated systems is quite substantial. Similar results are obtained for the tri‐hydrated cytidine and the 2‐deoxycytidine tautomeric forms. In aqueous solution of cytidine, syn‐ and syn‐clinal‐conformers оf the amino‐oxo tautomer should coexist with small amounts of syn‐ and syn‐clinal conformers оf imino‐oxo tautomer. For 2‐deoxycytidine an equilibrium has been found to exist between the syn‐ and anti‐conformers of the amino‐oxo and the imino‐oxo tautomers. The water‐assisted proton transfer reactions released through asynchronous concerted mechanism and the conformation of the sugar ring in nucleosides does not change during the tautomerization. [ABSTRACT FROM AUTHOR]

Background and Objectives: Colorectal cancer (CRC) is a malignant tumor with an extremely high incidence rate worldwide. This study explores the influence of mindfulness-based stress reduction (MBSR) in the care of patients with CRC undergoing bevacizumab (BVZ) plus XELOX chemotherapy, aiming at providing reliable reference and guidance for further improving their rehabilitation and prognosis.Methods: Between January 2019 and March 2020, 88 patients with CRC admitted consecutively to Jiangsu Cancer Hospital in China were enrolled in the study. Of them, 42 patients receiving BVZ plus XELOX chemotherapy, conventional care and MBSR intervention were assigned to the intervention group, and the remaining 46 patients receiving XELOX chemotherapy and conventional care were included in the control group. Clinical efficacy, safety and improvement in functional status were compared. Patients' psychological state, treatment compliance and self-care ability were evaluated. Finally, prognostic quality of life (QoL) was recorded at 1-year follow-up.Results: The overall response rate and incidence of adverse events in the intervention group were not different in the control group, but the total control rate and improvement rate in the intervention group were higher. After treatment, Sedation-Agitation Scale (SAS) and Self-Rating Depression Scale (SDS) scores in the intervention group were decreased, compliance and self-care ability were improved, all of which were better than in the control group. Prognostic follow-up showed that the QoL in the intervention group was also higher than in the control group.Conclusions: The combined use of BVZ in XELOX-based chemotherapy can improve the clinical outcome and functional status of patients with CRC. In addition, MBSR intervention implemented during chemotherapy can effectively optimize patients' psychological state and treatment compliance, strengthen their self-care ability and improve their prognostic QoL. [ABSTRACT FROM AUTHOR]

Simple Summary: We investigated the effect of combinational use of PARP inhibitors on cytotoxicity of 5-aza-dC in human cancer cell lines. The combinational treatment of 5-aza-dC and PARP inhibitor PJ-34 exhibited a stronger cytotoxicity compared with their treatment alone in blood cancer HL-60, U937, and colon cancer HCT116 and RKO cells. In microarray analysis, combinational treatment with PJ-34 and 5-aza-dC caused different broad changes in gene expression profiles compared with their single treatments in both HCT116 and RKO cells. The profiles of reactivation of silenced genes were also different in combination of PJ-34 and 5-aza-dC and their single treatments. The results suggest that a combination of 5-aza-dC and PARP inhibitor may be useful by inducing distinct transcriptional profile changes. Poly(ADP-ribose) polymerase (PARP) is involved in DNA repair and chromatin regulation. 5-Aza-2′-deoxycytidine (5-aza-dC) inhibits DNA methyltransferases, induces hypomethylation, blocks DNA replication, and causes DNA single strand breaks (SSBs). As the PARP inhibitor is expected to affect both DNA repair and transcriptional regulations, we investigated the effect of combinational use of PARP inhibitors on cytotoxicity of 5-aza-dC in human cancer cell lines. The combinational treatment of 5-aza-dC and PARP inhibitor PJ-34 exhibited a stronger cytotoxicity compared with their treatment alone in blood cancer HL-60, U937, and colon cancer HCT116 and RKO cells. Treatment with 5-aza-dC but not PJ-34 caused SSBs in HCT116 cell lines. Global genome DNA demethylation was observed after treatment with 5-aza-dC but not with PJ-34. Notably, in microarray analysis, combinational treatment with PJ-34 and 5-aza-dC caused dissimilar broad changes in gene expression profiles compared with their single treatments in both HCT116 and RKO cells. The profiles of reactivation of silenced genes were also different in combination of PJ-34 and 5-aza-dC and their single treatments. The results suggest that the combinational use of 5-aza-dC and PARP inhibitor may be useful by causing distinct transcriptional profile changes. [ABSTRACT FROM AUTHOR]

Mantled is a kind of fruit abnormality in oil palm and can cause serious yield loss of palm oil. It was reported that mantled phenotype could be resulted from the application of plant growth regulators (e.g. 2, 4-D) during tissue culture. However, the effect of 2, 4-D treatment on the development of mantled variation is still very limited. In this study, based on our present oil palm tissue culture system, the inflorescence explants were treated with different concentrations of 2,4-D at callus induction stage to induce mantled. Along with a known mantled sample as control, all 2,4-D treated samples were detected with an available DNA marker (kDEF1) for mantled identification, the expression of EgDEF1 transcripts (kDEF1 and tDEF1) and the accumulation of mantled related metabolites (deoxycytidine) were then analyzed using transcriptomics and metabolomics analysis. Detection of mantled by kDEF1 marker showed that kDEF1 was detected only in control (mantled) sample whereas none was found in 2,4-D treated samples. Furthermore, transcriptome analysis confirmed that kDEF1 transcript was not presented at all in 2,4-D treated samples. In contrast with earlier reports in mantled samples, tDEF1 was down-regulated and the accumulation of deoxycytidine was increased during callus induction. Therefore, the mantled variation was not identified at DNA, RNA and metabolite levels in 2,4-D treated samples, suggesting that high concentration of 2,4-D may not result in mantled variation during callus induction. However, similar research at embryogenesis stage could be till needed to explore more possibilities. [ABSTRACT FROM AUTHOR]

Aim: Comparison of first-line FOLFIRINOX (FFN) and nab-paclitaxel plus gemcitabine (NabGem) in patients with metastatic pancreatic ductal adenocarcinoma. Patients & methods: The authors analyzed data from 160 patients with metastatic pancreatic adenocarcinoma receiving first-line FFN (n = 43) or NabGem (n = 117). Results: FFN and NabGem were similar in median progression-free survival (24.43 vs 26.28 weeks; hazard ratio [HR]: 0.88) and medial overall survival (47.43 vs 42.86 weeks; HR: 0.90). Of the 43 patients receiving FFN, 26 (60.4%) were treated with second-line NabGem; 14/117 (12.0%) patients receiving NabGem received second-line FFN (p < 0.0001). In the FFN → NabGem and NabGem → FFN groups, median overall survival was 51.2 and 71.6 weeks (HR: 0.69; p = 0.15). In patients receiving NabGem, second-line FFN, compared with FOLFOX/CAPOX or FOLFIRI, improved median progression-free survival 2 (25.6 vs 12.1 weeks; HR: 0.47; p = 0.0067) and median overall survival 2 (39.0 vs 19.14 weeks; HR: 0.49; p = 0.032). Conclusion: First-line FFN and NabGem promote similar clinical outcomes. Second-line FFN should be considered after NabGem. [ABSTRACT FROM AUTHOR]

Aim: To compare the overall survival (OS) among patients who received first-line modified gemcitabine plus nab-paclitaxel (G/nab-P) or 5-fluorouracil, leucovorin, irinotecan and oxaliplatin (mFOLFIRINOX) for metastatic pancreatic cancer. Methods: A single-center, retrospective, real-world study was conducted. Results: The median OS was 9.4 months versus 7.5 months in the mFOLFIRINOX and modified G/Nab-P groups, respectively (p = 0.16). An exploratory subgroup analysis excluding patients who received one infusion and had an Eastern Cooperative Oncology Group performance score of 2 demonstrated similar OS of 11.3 months and 8.9 months, respectively. Median progression-free survival and time-to-treatment failure were not significantly different. Higher rates of adverse events were noted with mFOLFIRINOX. Conclusion: mFOLFIRINOX did not significantly prolong OS compared with modified G/nab-P and was associated with increased toxicities. [ABSTRACT FROM AUTHOR]

Background: Gemcitabine (Gem) alone or with Nab-paclitaxel (Gem-Nab) is used as second-line treatment for metastatic pancreatic adenocarcinoma (mPA) after FOLFIRINOX (FFX) failure; however, no comparative data exist. This study evaluates the efficacy and safety of adding Nab-paclitaxel to Gem for mPA after FFX failure.Methods: In this retrospective real-world multicenter study, from 2011 to 2019, patients with mPA receiving Gem-Nab (Gem 1000 mg/m² + Nab 125 mg/m², 3 out of 4 weeks) or Gem alone were included after progression on FFX.Results: A total of 427 patients were included. Patients receiving Gem-Nab had more metastatic sites, peritoneal disease and less PS 2 (24% vs. 35%). After median follow-up of 22 months, Gem-Nab was associated with better disease control rate (DCR) (56% vs. 32%; P < 0.001), progression-free survival (PFS) (3.5 vs. 2.3 months; 95% CI: 0.43-0.65) and overall survival (OS) (7.1 vs. 4.7 months; 95% CI: 0.53-0.86). After multivariate analysis, Gem-Nab and PS 0/1 were associated with better OS and PFS. Grade 3/4 toxicity was more frequent with Gem-Nab (44% vs. 29%).Conclusion: In this study, Gem-Nab was associated with better DCR, PFS and OS compared with Gem alone in patients with mPA after FFX failure, at the cost of higher toxicity. [ABSTRACT FROM AUTHOR]

The ergothioneine transporter ETT (formerly OCTN1; human gene symbol SLC22A4) is a powerful and highly specific transporter for the uptake of ergothioneine (ET). Recently, Sparreboom et al. reported that the ETT would transport nucleosides and nucleoside analogues such as cytarabine and gemcitabine with the highest efficiency. In our assay system, we could not detect any such transport. Subsequently, Sparreboom suggested that the intracellular metabolization of the nucleosides occurs so fast that the original compounds cannot be detected by LC–MS/MS after inward transport. Our current experiments with 293 cells disprove this hypothesis. Uptake of gemcitabine was easily detected by LC–MS/MS measurements when we expressed the Na+/nucleoside cotransporter CNT3 (SLC28A3). Inward transport was 1280 times faster than the intracellular production of gemcitabine triphosphate. The deoxycytidine kinase inhibitor 2-thio-2′-deoxycytidine markedly blocked the production of gemcitabine triphosphate. There was no concomitant surge in intracellular gemcitabine, however. This does not fit the rapid phosphorylation of gemcitabine. Uptake of cytarabine was very slow, but detection by MS was still possible. When the ETT was expressed and incubated with gemcitabine, there was no increase in intracellular gemcitabine triphosphate. We conclude that the ETT does not transport nucleosides. [ABSTRACT FROM AUTHOR]

Cytarabine (Ara-C) is the mainstay of treatment of acute myeloid leukemia (AML), but still, drug resistance and treatment-related toxicities are the main causes of treatment failure. Single nucleotide polymorphisms (SNPs) of the key genes involved in the metabolic pathway of Ara-C have been reported to affect the clinical outcome, so we aimed to investigate the potential association of SNPs of deoxycytidine kinase [DCK] 201C>T (rs2306744), DCK 360C>G (rs377182313) and cytidine deaminase (CDA) 79A>C (rs2072671) genes in adult Egyptian AML patients with the outcome. Genotyping of the studied SNPs was tested using PCR- RFLP technique in 142 adult de novo AML patients who received standard induction chemotherapy based on cytarabine and doxorubicin (3+7 protocol). The median (range) age of our patients was 38 (20-60) years. The studied SNPs genotypes had no significant influence on treatment response on day 28 of induction therapy. DCK 201 heterozygous CT genotype, DCK 201-T allele, [DCK 201(CC)/DCK 360(CC)/CDA 79(AC)] combination as well as hepatological, nephrological, neurological and hematological toxicities were independent prognostic markers on the survival of our AML patients. Nucleophosmin mutation was associated with the poor prognostic variant DCK 201-T and CDA 79-A alleles. Fms-like tyrosine3 kinase internal tandem duplication (FLT3-ITD) mutation was associated with the wild AA genotype of CDA 79A>C polymorphism, while FLT3-tyrosine kinase domain (TKD) mutation was associated with variant DCK360-G allele. These findings support the idea that the studied SNPs can be used as prognostic markers helping in tailored treatment for AML patients. [ABSTRACT FROM AUTHOR]

Background: There is paucity of investigations into immunotherapy or targeted therapy for postoperative locally recurrent pancreatic cancer. We aimed to assess the efficacy of stereotactic body radiotherapy (SBRT) plus pembrolizumab and trametinib in these patients.Methods: In this open-label, randomised, controlled, phase 2 study, participants were recruited from Changhai Hospital affiliated to the Naval Medical University, Shanghai, China. Eligible patients were aged 18 years or older with histologically confirmed pancreatic ductal adenocarcinoma characterised by mutant KRAS and positive immunohistochemical staining of PD-L1, Eastern Cooperative Oncology Group performance status of 0 or 1, and documented local recurrence after surgery followed by chemotherapy (mFOLFIRINOX [ie, 5-fluorouracil, oxaliplatin, irinotecan, and folinic acid] or 5-fluorouracil). Eligible participants were randomly assigned (1:1) using an interactive voice or web response system, without stratification, to receive SBRT with doses ranging from 35-40 Gy in five fractions, intravenous pembrolizumab 200 mg once every 3 weeks, and oral trametinib 2 mg once daily or SBRT (same regimen) and intravenous gemcitabine (1000 mg/m2) on day 1 and 8 of a 21-day cycle for eight cycles until disease progression, death, unacceptable toxicity, or consent withdrawal. The primary endpoint was overall survival in the intention-to-treat population. Safety was assessed in the as-treated population in all participants who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT02704156, and is now complete.Findings: Between Oct 10, 2016, and Oct 28, 2017, 198 patients were screened, of whom 170 patients were enrolled and randomly assigned to receive SBRT plus pembrolizumab and trametinib (n=85) or SBRT plus gemcitabine (n=85). As of the clinical cutoff date (Nov 30, 2020), median follow-up was 13·1 months (IQR 10·2-17·1). Median overall survival was 14·9 months (12·7-17·1) with SBRT plus pembrolizumab and trametinib and 12·8 months (95% CI 11·2-14·4) with SBRT plus gemcitabine (hazard ratio [HR] 0·69 [95% CI 0·51-0·95]; p=0·021). The most common grade 3 or 4 adverse effects were increased alanine aminotransferase or aspartate aminotransferase (ten [12%] of 85 in SBRT plus pembrolizumab and trametinib group vs six [7%] of 85 in SBRT plus gemcitabine group), increased blood bilirubin (four [5%] vs none), neutropenia (one [1%] vs nine [11%]), and thrombocytopenia (one [1%] vs four [5%]). Serious adverse events were reported by 19 (22%) participants in the SBRT plus pembrolizumab and trametinib group and 12 (14%) in the SBRT plus gemcitabine group. No treatment-related deaths occurred.Interpretation: The combination of SBRT plus pembrolizumab and trametinib could be a novel treatment option for patients with locally recurrent pancreatic cancer after surgery. Phase 3 trials are needed to confirm our findings.Funding: Shanghai Shenkang Center and Changhai Hospital.Translation: For the Chinese translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

Background: No reliable nomogram has been developed until date for predicting the survival in patients with unresectable pancreatic cancer undergoing treatment with gemcitabine plus nab-paclitaxel (GnP) or FOLFIRINOX.Methods: This analysis was conducted using clinical data of Japanese patients with unresectable pancreatic cancer undergoing GnP or FOLFIRINOX treatment obtained from a multicenter study (NAPOLEON study). A Cox proportional hazards model was used to identify the independent prognostic factors. A nomogram to predict 6-, 12-, and 18-month survival probabilities was generated, validated by using the concordance index (C-index), and calibrated by the bootstrapping method. And then, we attempted risk stratification for survival by classifying the patients according to the sum of the scores on the nomogram (total nomogram points).Results: A total of 318 patients were enrolled. A prognostic nomogram was generated using data on the Eastern Cooperative Oncology Group performance status, liver metastasis, serum LDH, serum CRP, and serum CA19-9. The C-indexes of the nomogram were 0.77, 0.72 and 0.70 for 6-, 12-, and 18-month survival, respectively. The calibration plot showed optimal agreement at all points. Risk stratification based on tertiles of the total nomogram points yielded clear separations of the survival curves. The median survival times in the low-, moderate-, and high-risk groups were 15.8, 12.8 and 7.8 months (P<0.05), respectively.Conclusions: Our nomogram might be a convenient and inexpensive tool to accurately predict survival in Japanese patients with unresectable pancreatic cancer undergoing treatment with GnP or FOLFIRINOX, and will help clinicians in selecting appropriate therapeutic strategies for individualized management. [ABSTRACT FROM AUTHOR]

Gemcitabine has been extensively applied in treating various solid tumors. Nonetheless, the clinical performance of gemcitabine is severely restricted by its unsatisfactory pharmacokinetic parameters and easy deactivation mainly because of its rapid deamination, deficiencies in deoxycytidine kinase (DCK), and alterations in nucleoside transporter. On this account, repeated injections with a high concentration of gemcitabine are adopted, leading to severe systemic toxicity to healthy cells. Accordingly, it is highly crucial to fabricate efficient gemcitabine delivery systems to obtain improved therapeutic efficacy of gemcitabine. A large number of gemcitabine pro-drugs were synthesized by chemical modification of gemcitabine to improve its biostability and bioavailability. Besides, gemcitabine-loaded nano-drugs were prepared to improve the delivery efficiency. In this review article, we introduced different strategies for improving the therapeutic performance of gemcitabine by the fabrication of pro-drugs and nano-drugs. We hope this review will provide new insight into the rational design of gemcitabine-based delivery strategies for enhanced cancer therapy. [ABSTRACT FROM AUTHOR]

Purpose: Drug resistance is a serious problem in leukemia therapy. A novel purine nucleoside analogue, nelarabine, is available for the treatment of children with T cell acute lymphoblastic leukemia. We investigated the mechanisms of drug resistance to nelarabine. Methods: Nelarabine-resistant cells were selected by stepwise and continuous exposure to nelarabine using the limiting dilution method in human B and T cell lymphoblastic leukemia cell lines. Expression analysis was performed using real-time polymerase chain reaction, and epigenetic analysis was performed using methylation-specific polymerase chain reaction and chromatin immunoprecipitation. Results: The RNA expression level for deoxycytidine kinase (dCK) was decreased in nelarabine-resistant leukemia cells. There were no differences between the parental and nelarabine-resistant leukemia cells in the methylation status of the promoter region of the dCK gene. In the chromatin immune precipitation assay, decreased acetylation of histones H3 and H4 bound to the dCK promoter was seen in the nelarabine-resistant cells when compared to the parental cells. Furthermore, treatment with a novel histone deacetylase inhibitor, vorinostat, promoted the cytotoxic effect of nelarabine along with increased expression of the dCK gene, and it increased acetylation of both histones H3 and H4 bound to the dCK promoter in nelarabine-resistant leukemia cells. The combination index showed that the effect of nelarabine and vorinostat was synergistic. Conclusion: This study reports that nelarabine with vorinostat can promote cytotoxicity in nelarabine-resistant leukemia cells through epigenetic mechanisms. [ABSTRACT FROM AUTHOR]

The 4S–Ag(I)–C base pair (4S, 3-((2-(methylthio)pyrimidin-4-yl)thio)propane-1,2-diol; C, deoxycytidine) represents the first metal-mediated base pair comprising an S-glycosidic nucleoside analogue. We report here the synthesis of the phosphoramidite suitable for the automated solid-phase synthesis of DNA oligonucleotides containing 4S and its silver(I)-binding ability. The DNA duplexes comprising a 4S:C mispair exhibit a large thermal stabilization upon the addition of one equivalent of silver ions, giving rise to the formation of the above-mentioned silver(I)-mediated base pair. By formally replacing the sulfur atom in the glycosidic bond by an oxygen atom, i.e., by applying 3-((2-(methylthio)pyrimidin-4-yl)oxy)propane-1,2-diol (4 O) as the artificial nucleoside analogue, the participation of this atom as a donor atom in silver(I)-mediated base pairing is shown to be neglectable. Supplemental data for this article is available online at [ABSTRACT FROM AUTHOR]

It has long been debated whether easily reducible azide groups can withstand the conditions of oligonucleotide synthesis by phosphoramidite chemistry. We have synthesized various 2′‐ and 3′‐azido modified nucleosides and immobilized them on controlled pore glass (CPG) to be used as starting material for the synthesis of oligonucleotides (ONs) with 3′‐terminal azide (attached to C2′ or C3′). In a model study, immobilized 3′‐azidoadenosine was used as a starting block for the synthesis of a series of oligodeoxynucleotides (ODNs) of increasing length. Upon synthesis, the ODNs were enzymatically digested into monomers and analyzed by RP‐HPLC. A peak corresponding to 3′‐azidoadenosine was clearly identified in all samples. Quantitative analysis showed that 3′‐azidoadenosine was present in nearly the expected ratio to deoxycytidine, which was used as an internal standard. Most importantly, the ratio remained the same for all three ODNs regardless of their length, demonstrating that a higher number of coupling cycles does not lead to higher degradation of the azide. Thus, 2′‐ or 3′‐azido nucleosides attached to a solid support are excellent starting materials for the synthesis of oligonucleotides with 3′‐terminal azide. [ABSTRACT FROM AUTHOR]

Context: Previous studies have discovered a high expression rate of Mucin 1 (MUC1) in pancreatic cancer tissue, and its abnormal glycosylation causes MUC1 to expose new protein epitopes or glycoantigens.Aims: To investigate the therapeutic effect of drug-loaded gemcitabine polybutylcyanoacrylate nanoparticles coupled with anti-human MUC1 monoclonal antibody (mAb) on human pancreatic cancer cell line and xenografts.Settings and Design: Randomized controlled trial.Materials and Methods: Gemcitabine-loaded nanospheres were prepared by emulsion polymerization; then, the anti-MUC1 mAb coupled with gemcitabine polybutylcyanoacrylate nanoparticles (MUC1-GEM-PBCA-NP) was prepared by chemical cross-linking. Cell-killing rates were detected by MTT assay in in vitro study, and changes in tumor cell cycle and apoptosis after treatment were detected by flow cytometry. Furthermore, in in vivo study, MUC1-GEM-PBCA-NP was injected into nude mice through the tail vein. Gemcitabine-loaded polybutylcyanoacrylate nanoparticles (GEM-PBCA-NP), gemcitabine bulk drug and empty nanoparticles (PBCA-NP), and normal saline blank control groups were established. Finally, data obtained were compared between groups.Results: Compared with the control group, the cell-killing rate of each experimental group was significantly different (P < 0.05) in in vitro study, among which the MUC1-GEM-PBCA-NP group was significantly higher than other groups (P < 0.05). In addition, the apoptosis rate of the MUC1-GEM-PBCA-NP treatment group was significantly higher than that of other groups (P < 0.05). Furthermore, in in vivo study, the tumor inhibition rate of the MUC1-GEM-PBCA-NP treatment group was (68.14% ±1.66%), which was significantly higher than other control groups (P < 0.05). Finally, at the end of the treatment, the average tumor mass of the MUC1-GEM-PBCA-NP treatment group was (471.61 mg ± 12.16 mg), which was significantly lower than those of other control groups (P < 0.05).Conclusions: MUC1-GEM-PBCA-NP could have an excellent inhibitory effect on tumors; thus, requiring further study. [ABSTRACT FROM AUTHOR]

Background: Cyclin-dependent kinase inhibitors (CKIs) are the negative regulator of cell cycle progression, which inhibits cyclincdk complexes, resulting in cell cycle arrest. Recently, we evaluated the effect of 5-Aza-CdR on DNMT1 gene expression in the WCH-17 hepatocellular carcinoma (HCC) cell line. Objectives: The current study was designed to analyze the effects of 5-aza-2'--deoxycytidine (5-Aza-CdR, decitabine), 5-azacytidine (5-AzaC, vidaza), and 5'-fluoro-2'-deoxycytidine (FdCyd) on INK4a/ARF, CIP/KIP, and DNA methyltransferase 1 gene expression, apoptosis induction, and cell growth inhibition in colon cancer HCT-116 cell line. Methods: The colon cancer HCT-116 cell line was treated with 5-azaC, 5-Aza-CdR, and FdCyd at 24 and 48h. To determine colon cancer HCT-116 cell viability, cell apoptosis, and the relative expression level of the INK4a/ARF, CIP/KIP, and DNA methyltransferase 1 genes, MTT assay, flow cytometry, and qRT-PCR were done, respectively. Results: 5-azaC, 5-Aza-CdR, and FdCyd significantly inhibited colon cancer HCT-116 cell growth and induced apoptosis. Besides, they significantly increased CIP/KIP (p21CIP1, p27KIP1, and p57KIP2) and INK4 (p14ARF, p15INK4b, and p16INK4a) and decreased DNMT1 gene expression. Besides, minimal and maximal apoptosis were seen in the groups treated with FdCyd and 5-Aza-CdR, respectively. The IC50 for CAF for FdCyd was 1.72 - 0.23 and 1.63 - 0.21μM at 24 and 48h, respectively. The IC50 for CAF for 5-AzaC was 2.18 - 0.33 and 1.98 - 0.29 μM at 24 and 48h, respectively. The IC50 for CAF for 5-Aza-CdR was 4.08 - 0.61 and 3.18 - 0.50 μM at 24 and 48h, respectively. Conclusions: The 5-azac, 5-Aza-CdR, and FdCyd can reactivate the INK4a/ARF and CIP/KIP families through inhibition of DNMT1 activity. [ABSTRACT FROM AUTHOR]

CTP synthases (CTPS) comprise a protein family of the five members CTPS1-CTPS5 in Arabidopsis, all located in the cytosol. Specifically, downregulation of CTPS2 by amiRNA technology results in plants with defects in chlorophyll accumulation and photosynthetic performance early in development. CTP and its deoxy form dCTP are present at low levels in developing seedlings. Thus, under conditions of fast proliferation, the synthesis of CTP (dCTP) can become a limiting factor for RNA and DNA synthesis. The higher sensitivity of ami-CTPS2 lines toward the DNA-Gyrase inhibitor ciprofloxacin, together with reduced plastid DNA copy number and 16S and 23S chloroplast ribosomal RNA support this view. High expression and proposed beneficial biochemical features render CTPS2 the most important isoform for early seedling development. In addition, CTPS2 was identified as an essential enzyme in embryo development before, as knock-out mutants were embryo lethal. In line with this, ami-CTPS2 lines also exhibited reduced seed numbers per plant. [ABSTRACT FROM AUTHOR]

Decitabine (DAC), a DNA methyltransferase (DNMT) inhibitor is a novel anti-cancer drug regulating epigenetic mechanisms. Similar to conventional anti-cancer drugs, drug resistance to DAC also has been reported, resulting in tumor recurrence. Our previous study using colorectal cancer HCT116 cells found the decrease in deoxycytidine kinase (dCK) (activation enzyme of DAC) and the increase in cytidine deaminase (inactivation enzyme of DAC) in acquired DAC-resistant HCT116 (HCT116/DAC) cells. The aim of our study was to clarify the involvement of dCK and CDA in DAC resistance. In order to tackle DAC resistance, it was also examined whether other DNMT inhibitors such as azacytidine (AC) and polyphenols are effective in DAC-resistant cancer cells. When dCK siRNA was transfected into HCT116 cells, IC 50 value of DAC increased by about 74-fold and reached that of HCT116/DAC cells with attenuated dCK. dCK siRNA to HCT116 cells also abolished DNA demethylation effects of DAC. In contrast, CDA siRNA to HCT116 cells did not influence the efficacy of DAC. In addition, CDA siRNA to HCT116/DAC cells with increased CDA did not restore the compromised effects of DAC. These results suggested that attenuated dCK but not increased CDA mainly contributed to DAC resistance. Regarding dCK in HCT116/DAC cells, a point mutation with amino acid substitution was observed while the product size and expression of mRNA coding region did not change, suggesting that dCK protein was decreased by post-transcriptional regulation. AC and polyphenols showed no cross-resistance in HCT116/DAC cells. AC but not polyphenols exerted DNA demethylation effect. Among polyphenols, curcumin (Cur) showed the most synergistic cytotoxicity in combination with AC while DNA demethylation effect of AC was partly maintained. Taken together, combination of AC and Cur would be a promising alternative to tackle DAC resistance mainly due to attenuated dCK. [Display omitted] • Attenuated deoxycytidine kinase mainly contributed to acquired decitabine resistance. • Azacytidine exerted DNA demethylation effect in decitabine-resistant cells. • Azacytidine and curcumin enhanced cytotoxicity in decitabine-resistant cells. [ABSTRACT FROM AUTHOR]

Background: The prognosis of patients with advanced biliary tract cancer who have progressed on gemcitabine plus cisplatin is dismal. We aimed to investigate the efficacy and safety of second-line liposomal irinotecan plus fluorouracil and leucovorin in patients with metastatic biliary tract cancer that has progressed on gemcitabine plus cisplatin.Methods: This multicentre, open-label, randomised, phase 2b (NIFTY) study was done at five academic institutions in South Korea and included patients aged 19 years or older with histologically or cytologically confirmed metastatic biliary tract cancer that had progressed on first-line gemcitabine plus cisplatin and an Eastern Cooperative Oncology Group performance status of 0 or 1. By use of an interactive web-based response system integrated with an electronic data capture system, patients were randomly assigned (1:1) using permuted blocks (block size 4) to receive either intravenous liposomal irinotecan (70 mg/m2 for 90 min) plus intravenous leucovorin (400 mg/m2 for 30 min) and intravenous fluorouracil (2400 mg/m2 for 46 h) every 2 weeks or leucovorin and fluorouracil only every 2 weeks, and were stratified by primary tumour site, previous surgery with curative intent, and participating centre. Study treatment was continued until the patient had disease progression or unacceptable toxicities, or withdrew consent. The primary endpoint was blinded independent central review (BICR)-assessed progression-free survival. The primary endpoint and safety were assessed in the full analysis set and the safety analysis set, respectively, both of which comprised all randomly assigned patients who received at least one dose of the study treatment. This trial is registered with ClinicalTrials.gov, NCT03524508, and enrolment is complete.Findings: Between Sept 5, 2018, and Feb 18, 2020, 193 patients were screened for eligibility, of whom 174 (88 in the liposomal irinotecan plus fluorouracil and leucovorin group and 86 in the fluorouracil plus leucovorin group) were enrolled and included in the full analysis and safety analysis sets. At a median follow-up of 11·8 months (IQR 7·7-18·7), the median BICR-assessed progression-free survival was significantly longer in the liposomal irinotecan plus fluorouracil and leucovorin group (7·1 months, 95% CI 3·6-8·8) than in the fluorouracil and leucovorin group (1·4 months, 1·2-1·5; hazard ratio 0·56, 95% CI 0·39-0·81; p=0·0019). The most common grade 3-4 adverse events were neutropenia (21 [24%] of 88 in the liposomal irinotecan plus fluorouracil and leucovorin group vs one [1%] of 86 in the fluorouracil and leucovorin group) and fatigue or asthenia (11 [13%] vs three [3%]). Serious adverse events occurred in 37 (42%) patients receiving liposomal irinotecan plus fluorouracil and leucovorin and 21 (24%) patients receiving fluorouracil and leucovorin. There were no treatment-related deaths.Interpretation: Adding liposomal irinotecan to fluorouracil and leucovorin significantly improved BICR-assessed progression-free survival in patients with advanced biliary tract cancer. Liposomal irinotecan plus fluorouracil and leucovorin could be considered a standard-of-care second-line therapy for advanced biliary tract cancer.Funding: Servier and HK inno.N Translation: For the Korean translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

CD73, a cell surface-localized ecto-5'-nucleotidase, is the major enzymatic source of extracellular adenosine. Canonically, it plays multiple roles in cancer-related processes via its metabolite. As a druggable target, clinical trials targeting CD73 in various malignant diseases are currently ongoing. Here, we report the ecto-5'-nucleotidase-independent functions of CD73 in pancreatic ductal adenocarcinoma (PDAC). Our findings support that the elevated expression of CD73 in PDAC cells promotes gemcitabine (GEM) resistance by activating AKT. We discovered that a large amount of intracellular CD73 are localized in the endoplasmic reticulum membrane. Intracellular CD73 physically interacts with major vault protein to activate the SRC-AKT circuit. Troglitazone (TGZ) is a peroxisome proliferator-activated receptor gamma agonist that could inhibit the expression of CD73. The administration of TGZ markedly enhances sensitivity to GEM via downregulating CD73 in PDAC. Our findings support that CD73 could be targeted to overcome chemoresistance in PDAC. [ABSTRACT FROM AUTHOR]

CTP synthases (CTPS) comprise a protein family of the five members CTPS1-CTPS5 in Arabidopsis, all located in the cytosol. Specifically, downregulation of CTPS2 by amiRNA technology results in plants with defects in chlorophyll accumulation and photosynthetic performance early in development. CTP and its deoxy form dCTP are present at low levels in developing seedlings. Thus, under conditions of fast proliferation, the synthesis of CTP (dCTP) can become a limiting factor for RNA and DNA synthesis. The higher sensitivity of ami-CTPS2 lines toward the DNA-Gyrase inhibitor ciprofloxacin, together with reduced plastid DNA copy number and 16S and 23S chloroplast ribosomal RNA support this view. High expression and proposed beneficial biochemical features render CTPS2 the most important isoform for early seedling development. In addition, CTPS2 was identified as an essential enzyme in embryo development before, as knock-out mutants were embryo lethal. In line with this, ami-CTPS2 lines also exhibited reduced seed numbers per plant.

Resistance to cytarabine is an important cause of therapy failure in persons with acute myeloid leukemia (AML). Deoxycytidine kinase, encoded by DCK, catalyzes phosphorylation of cytarabine to cytarabine monophosphate, a necessary step for eventual incorporation of cytarabine triphosphate into DNA and for clinical efficacy. Whether DCK mutations make AML cells resistant to cytarabine is controversial. We studied DCK mutations and messenger RNA (mRNA) concentrations in leukemia cells from 10 subjects with AML who received cytarabine-based therapy and relapsed and in 2 artificially induced cytarabine-resistant AML cell lines. DCK mutations were detected in 4 subjects with AML relapsing after achieving a complete remission and receiving high-dose cytarabine postremission therapy. Most mutations were in exons 4–6 and were not present before therapy. DCK was also mutated in cytarabine-resistant but not parental AML cell lines. DCK mRNA concentrations were significantly decreased in cytarabine-resistant K562 and SHI-1 cells compared with cytarabine-sensitive parental cells. Mutation frequency of DCK and mRNA concentration did not correlate with the extent of cytarabine resistance indicating other factors operate. Overexpression of wild-type DCK restored cytarabine sensitivity to previously resistant leukemia cell lines. Our data contribute to the understanding of cytarabine resistance in persons with AML. [ABSTRACT FROM AUTHOR]

Background: Berzosertib (formerly M6620, VX-970) is a highly potent and selective, first-in-class inhibitor of ataxia telangiectasia and Rad3-related protein kinase (ATR). We assessed multiple ascending doses of berzosertib + gemcitabine ± cisplatin in patients with resistant/refractory advanced solid tumours.Methods: We evaluated the safety, tolerability, pharmacokinetics (PK) and preliminary efficacy of intravenous berzosertib + gemcitabine ± cisplatin using a standard 3 + 3 dose-escalation design. The starting doses were berzosertib 18 mg/m2, gemcitabine 875 mg/m2 and cisplatin 60 mg/m2.Results: Fifty-two patients received berzosertib + gemcitabine and eight received berzosertib + gemcitabine + cisplatin. Four patients receiving berzosertib + gemcitabine had a total of seven dose-limiting toxicities (DLTs) and three receiving berzosertib + gemcitabine + cisplatin had a total of three DLTs. Berzosertib 210 mg/m2 (days 2 and 9) + gemcitabine 1000 mg/m2 (days 1 and 8) Q3W was established as the recommended Phase 2 dose (RP2D); no RP2D was determined for berzosertib + gemcitabine + cisplatin. Neither gemcitabine nor cisplatin affected berzosertib PK. Most patients in both arms achieved a best response of either partial response or stable disease.Conclusions: Berzosertib + gemcitabine was well tolerated in patients with advanced solid tumours and showed preliminary efficacy signs.Clinical Trial Identifier: NCT02157792. [ABSTRACT FROM AUTHOR]

Dodecamer duplex DNA containing anomeric (α/β‐d) and enantiomeric (β‐l/β‐d) 2'‐deoxycytidine mismatches was studied with respect to base pair stability in the absence and presence of silver ions. Stable duplexes with silver‐mediated cytosine–cytosine pairs were formed by all anomeric and enantiomeric combinations. Stability changes were observed depending on the composition of the mismatches. Most strikingly, the new silver‐mediated base pair of anomeric α‐d‐dC with enantiomeric β‐l‐dC is superior to the well‐noted β‐d/β‐d‐dC pair in terms of stability. CD spectra were used to follow global helical changes of DNA structure. [ABSTRACT FROM AUTHOR]

Background: Modified FOLFIRINOX and gemcitabine plus nab-paclitaxel (GEM-NAB) have been recommended as first-line therapies for advanced pancreatic cancer (PC). Due to the lack of evidence to directly compare them, we conducted this network meta-analysis to indirectly compare the effectiveness and toxicity of modified FOLFIRINOX and GEM-NAB.Methods: The eligible retrospective studies on treatments related to modified FOLFIRINOX and GEM-NAB up to 4 April 2020 were searched and assessed. We used the frequentist model to analyze the survival and toxicity data between different treatments. Pooled analysis for overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and events of toxicity were analyzed in this study.Results: Twenty-two studies were involved in this network meta-analysis. The comparisons on OS and PFS showed that modified FOLFIRINOX and GEM-NAB had similar treatment efficacy (OS: 1.13; 95% CI: 0.78-1.63; PFS: HR: 1.19; 95% CI: 0.85-1.67). GEM-NAB was more effective than modified FOLFIRINOX based on the result of ORR (RR: 1.43; 95% CI: 1.04-1.96). Moreover, our analysis showed a similar toxicity profile between modified FOLFIRINOX and GEM-NAB.Conclusions: The current evidence showed that modified FOLFIRINOX and GEM-NAB were similar in survival and toxicity. Many factors should be considered for in the formulation of optimal treatment, and our meta-analysis could provide some guidance to treatment selection in the first-line setting for advanced PC. [ABSTRACT FROM AUTHOR]

Background: Gemcitabine plus platinum as the first-line chemotherapy for cholangiocarcinoma (CCA) has limited efficacy. The aim of this study was to evaluate the effectiveness of modified FOLFIRINOX (mFOLFIRINOX) compared to that of gemcitabine plus oxaliplatin (Gemox) for patients with locally advanced or metastatic CCA.Methods: From January 2016 to December 2019, consecutive patients who were diagnosed with locally advanced or metastatic CCA were treated with either mFOLFIRINOX or Gemox as a first-line chemotherapy. The main endpoint was Progression free survival (PFS). The second endpoints were Overall survival (OS), Disease control rate (DCR) and incidence of severe toxicity (grade 3-4). Tumors were evaluated at baseline and thence every 4-6 weeks. The study was designed and carried out in accordance with the principles of the declaration of Helsinki, approved by the Ethics Committee of Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine (XHEC-D-2020-154) and registered with ClinicalTrials.gov , number NCT04305288 (registration date: 12/03/2020).Results: Of 49 patients in this study, 27 were in the FOLFIRINOX regimen group and 22 in the Gemox regimen group. There were no significant differences between groups in baseline characteristics. The DCR was 77.8% in the mFOLFIRINOX group and 63.5% in the Gemox group. The corresponding median PFS was 9.9 months (95% confidence interval [CI], 7.3-12.4) in the mFOLFIRINOX group versus 6.4 months (95% CI,3.6-9.2, p = 0.040) in the Gemox group. The corresponding median OS was 15.7 months (95% CI, 12.5-19.0) versus 12.0 months (95% CI, 9.3-14.8, p = 0.099). Significantly more grade 3-4 vomiting occurred in the mFOLFIRINOX than the Gemox groups (7 (25.9%) vs 1 (4.5%), p = 0.044).Conclusions: First-line mFOLFIRINOX offered more promising results in patients with advanced or metastatic CCA. [ABSTRACT FROM AUTHOR]

Aim: To explore the role of DNA methylation in the innate immunity of the dental pulp, this study investigated the effect of 5‐aza‐2'‐deoxycytidine (AZA) on lipoteichoic acid (LTA)‐induced cytokine production and related intracellular signalling pathways in human odontoblast‐like cells (hOBs). Methodology: hOBs were cultured and differentiated from human dental pulp tissue, and the odontoblastic phenotype of the cells was detected using immunofluorescence, qRT‐PCR and Western blotting. hOBs were pretreated with AZA and then stimulated with 10 μg mL−1 LTA. The levels of 42 cytokines related to immunity and inflammation were examined using a cytokine antibody array and verified using qRT‐PCR and ELISA. The effect of AZA on the LTA‐induced NF‐κB and MAPK signalling pathways was explored using Western blotting. The cells were treated with the specific NF‐κB inhibitor PDTC and MAPK inhibitors (the ERK inhibitor U0126, the p38 inhibitor SB203580, and the JNK inhibitor SP600125) to further confirm the role of the signalling pathways in LTA‐treated hOBs. DNA immunoprecipitation–PCR was used to examine the dynamic methylation status of the gene promoters of myeloid differentiation primary response 88 (MyD88) and tumour necrosis factor receptor‐associated factor 6 (TRAF6) in the LTA‐induced hOBs. Statistical analyses of the differences between two groups were performed using Student's t‐test. One‐way analysis of variance (anova) or repeated‐measures anova with a post hoc Dunnett's test was used to assess the differences between multiple sets of data. P < 0.05 was considered to be statistically significant. Results: The odontoblastic markers were significantly higher in hOBs than those in human dental pulp cells (hDPCs) (P < 0.05). According to the cytokine antibody array results, hOBs pretreated with AZA had significantly increased production of several inflammatory cytokines (P < 0.05), in which the expression levels of IL‐6 and IL‐8 were the most dramatically increased upon LTA stimulation (P < 0.01). Furthermore, AZA resulted in the significant upregulation of p‐IKKα/β, p‐IκBα, p‐p65, p‐p38 and p‐ERK in LTA‐stimulated hOBs (P < 0.01). Treatment with the NF‐κB pathway inhibitor suppressed both IL‐6 and IL‐8 expression (P < 0.05), whereas inhibitors of the MAPK pathway (SB203580 and SP600125) did not. In LTA‐treated hOBs, AZA significantly increased the expression levels of TRAF6 and MyD88 (P < 0.05). AZA induced MyD88 promoter hypomethylation but did not affect TRAF6 methylation. Conclusion: AZA regulated the LTA‐induced inflammatory response through the NF‐κB signal pathway in hOBs. This study highlights the important role of DNA methylation in the immunity defence of odontoblasts during the dental pulp immunity response to caries. [ABSTRACT FROM AUTHOR]

KRAS mutation is associated with the progression and growth of pancreatic cancer and contributes to chemo-resistance, which poses a significant clinical challenge in pancreatic cancer. Here, we developed a RT22-ep59 antibody (Ab) that directly targets the intracellularly activated GTP-bound form of oncogenic KRAS mutants after it is internalized into cytosol by endocytosis through tumor-associated receptor of extracellular epithelial cell adhesion molecule (EpCAM) and investigated its synergistic anticancer effects in the presence of gemcitabine in pancreatic cancer. We first observed that RT22-ep59 specifically recognized tumor-associated EpCAM and reached the cytosol by endosomal escape. In addition, the anticancer effect of RT22-ep59 was observed in the high-EpCAM-expressing pancreatic cancer cells and gemcitabine-resistant pancreatic cancer cells, but it had little effect on the low-EpCAM-expressing pancreatic cancer cells. Additionally, co-treatment with RT22-ep59 and gemcitabine synergistically inhibited cell viability, migration, and invasion in 3D-cultures and exhibited synergistic anticancer activity by inhibiting the RAF/ERK or PI3K/AKT pathways in cells with high-EpCAM expression. In an orthotopic mouse model, combined administration of RT22-ep59 and gemcitabine significantly inhibited tumor growth. Furthermore, the co-treatment suppressed cancer metastasis by blocking EMT signaling in vitro and in vivo. Our results demonstrated that RT22-ep59 synergistically increased the antitumor activity of gemcitabine by inhibiting RAS signaling by specifically targeting KRAS. This indicates that co-treatment with RT22-ep59 and gemcitabine might be considered a potential therapeutic strategy for pancreatic cancer patients harboring KRAS mutation. [ABSTRACT FROM AUTHOR]

Epigenetic gene silencing by DNA methylation and histone methylation by EZH2 play an important role in the development of acute myeloid leukemia (AML). EZH2 catalyzes the trimethylation of histone H3-lysine 27-trimethylated (H3K27me3). These epigenetic alterations silence the expression of the genes that suppress leukemogenesis. Reversal of this gene silencing by 5-aza-2'-deoxycytidine (5-Aza-CdR), an inhibitor of DNA methylation, and by 3-deazaneplanocin-A (DZNep), an inhibitor of EZH2, results in synergistic gene reactivation and antileukemic interaction. The objective of this study is to determine if the addition of another epigenetic agent could further enhance the antileukemic action of these inhibitors of DNA and histone methylation. Vitamin C (Vit C) is reported to enhance the antineoplastic action of 5-Aza-CdR on AML cells. The mechanism responsible for this action of Vit C is due to its function as a cofactor of alpha-ketoglutarate-dependent dioxyge- nases (a-KGDD). The enhancement by Vit C of the catalytic activity of a-KGDD of the ten eleven translocation (TET) pathway, as well as of the Jumonji C histone demethylases (JHDMs), is shown to result in demethylation of DNA and histones, leading to reactivation of tumor suppressor genes and an antineoplastic effect. This action of Vit C has the potential to complement the antileukemic action of 5-Aza-CdR and DZNep. We observe that Vit C remarkably increases the antineoplastic activity of 5-Aza-CdR and DZNep against myeloid leukemic cells. An important step to bring this novel epigenetic therapy to clinical trial in patients with AML is the determination of its optimal dose schedule. [ABSTRACT FROM AUTHOR]

Background: Peripheral intravenous injection of gemcitabine often causes vascular pain; however, preventive measures have not yet been established.Objectives: This study focused on identifying predictive factors for gemcitabine-induced vascular pain.Methods: We retrospectively analyzed risk factors for developing vascular pain in patients with pancreatic cancer receiving gemcitabine infusions at our institution. Infusions were divided into groups according to presence or absence of vascular pain symptoms, and variables were compared. Odds ratios for risk factors were calculated using logistic regression analyses.Results: Overall, 272 patients with pancreatic cancer were subjected to 725 gemcitabine infusions, and of these, 18.4% (n = 50) experienced vascular pain. There were significant differences in the gemcitabine dose (P = 0.025), dose of gemcitabine/body surface area (BSA; P = 0.004), concentration of gemcitabine (P = 0.025), and hot pack use (P = 0.011) between the vascular pain and no vascular pain groups. Multivariable analyses indicated that gemcitabine dose/BSA and lack of hot pack use were risk factors for developing vascular pain. Moreover, on administration of a higher dosage (>930 mg/m2), the incidence of vascular pain in patients using a hot pack (6.7%) was significantly lower than that in patients not provided a hot pack (16.2%).Conclusions and Relevance: High gemcitabine dosages and lack of hot pack use were predictive factors for gemcitabine-induced vascular pain in patients with pancreatic cancer. Patients receiving gemcitabine treatment should apply a hot pack to the injection site. Scrupulous clinical attention is required for patients presenting with these risk factors to improve pain management. [ABSTRACT FROM AUTHOR]

Background: Pancreatic ductal adenocarcinoma (PDAC) is still a highly fatal malignancy among the most common cancers. More powerful treatments are expecting to bring hope for patients. Biweekly gemcitabine/nab-paclitaxel/S-1 (GAS) was proved safe and effective for patients with locally advanced pancreatic cancer in Japan. The objective of this study is to evaluate the feasibility and toxicity of GAS (repeated every 3 weeks) in the treatment of locally advanced or advanced pancreatic cancer and determine the recommended dose of S-1 in this combination.Methods: This is an open-label, single-arm, and single-center phase I trial. Patients who have been diagnosed with locally advanced or advanced PDAC pathologically without previous systemic treatments will be enrolled and be treated with GAS chemotherapy every 3 weeks (nab-paclitaxel 125 mg/m 2, ivgtt, day1, 8; gemcitabine 1000 mg/m2, day1, 8; different doses of S-1 within a dose escalation scheme) until the presence of disease progression (PD), intolerable adverse events (AEs), or requirement of patients and researchers. The primary endpoints are maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). The secondary endpoints include safety, objective response rate (ORR), progression-free survival (PFS) and overall survival (OS).Discussion: This trial will adjust the administration of GAS to make it more effective for Chinese patients, while exploring the toxicity and feasibility of this adjustment.Trial Registration: ChiCTR, ( ChiCTR1900027833 ). Registered 30 November 2019. [ABSTRACT FROM AUTHOR]

Abstract Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor response to chemo- and (modest-dose conventionally fractionated) radio-therapy. Emerging evidence suggests that pancreatic stellate cells (PSCs) secrete deoxycytidine, which confers resistance to gemcitabine. In particular, deoxycytidine was detected by analysis of metabolites in fractionated media from different mouse PSCs, showing that it caused PDAC cells chemoresistance by reducing the capacity of deoxycytidine kinase (dCK) for gemcitabine phosphorylation. However, data on human models are missing and dCK expression was not associated with clinical efficacy of gemcitabine. We recently established co-culture models of hetero-spheroids including primary human PSCs and PDAC cells showing their importance as a platform to test the effects of cancer- and stroma-targeted drugs. Here, we discuss the limitations of previous studies and the potential use of above-mentioned models to study molecular mechanisms underlying chemo- and radio-resistance.