Combining 2D angiogenesis and 3D osteosarcoma microtissues to improve vascularization.

Angiogenesis is now well known for being involved in tumor progression, aggressiveness, emergence of metastases, and also resistance to cancer therapies. In this study, to better mimic tumor angiogenesis encountered in vivo, we used 3D culture of osteosarcoma cells (MG-63) that we deposited on 2D endothelial cells (HUVEC) grown in monolayer. We report that endothelial cells combined with tumor cells were able to form a well-organized network, and that tubule-like structures corresponding to new vessels infiltrate tumor spheroids. These vessels presented a lumen and expressed specific markers as CD31 and collagen IV. The combination of 2D endothelial cells and 3D microtissues of tumor cells also increased expression of angiogenic factors as VEGF, CXCR4 and ICAM1. The cell environment is the key point to develop tumor vascularization in vitro and to be closer to tumor encountered in vivo.

Endothelial microparticles released by activated protein C protect beta cells through EPCR/PAR1 and annexin A1/FPR2 pathways in islets.

Islet transplantation is associated with early ischaemia/reperfusion, localized coagulation and redox-sensitive endothelial dysfunction. In animal models, islet cytoprotection by activated protein C (aPC) restores islet vascularization and protects graft function, suggesting that aPC triggers various lineages. aPC also prompts the release of endothelial MP that bear EPCR, its specific receptor. Microparticles (MP) are plasma membrane procoagulant vesicles, surrogate markers of stress and cellular effectors. We measured the cytoprotective effects of aPC on endothelial and insulin-secreting Rin-m5f ß-cells and its role in autocrine and paracrine MP-mediated cell crosstalk under conditions of oxidative stress. MP from aPC-treated primary endothelial (EC) or ß-cells were applied to H2 O2 -treated Rin-m5f. aPC activity was measured by enzymatic assay and ROS species by dihydroethidium. The capture of PKH26-stained MP and the expression of EPCR were probed by fluorescence microscopy and apoptosis by flow cytometry. aPC treatment enhanced both annexin A1 (ANXA1) and PAR-1 expression in EC and to a lesser extent in ß-cells. MP from aPC-treated EC (eMaPC ) exhibited high EPCR and annexin A1 content, protected ß-cells, restored insulin secretion and were captured by 80% of ß cells in a phosphatidylserine and ANXA1-dependent mechanism. eMP activated EPCR/PAR-1 and ANXA1/FPR2-dependent pathways and up-regulated the expression of EPCR, and of FPR2/ALX, the ANXA1 receptor. Cytoprotection was confirmed in H2 O2 -treated rat islets with increased viability (62% versus 48% H2 O2 ), reduced apoptosis and preserved insulin secretion in response to glucose elevation (16 versus 5 ng/ml insulin per 10 islets). MP may prove a promising therapeutic tool in the protection of transplanted islets.

Erlotinib: another candidate for the therapeutic drug monitoring of targeted therapy of cancer? A pharmacokinetic and pharmacodynamic systematic review of literature.

Erlotinib is currently marketed at fixed standard dosage against pancreatic cancer and non-small-cell lung carcinoma. However, erlotinib pharmacokinetics (PK) is characterized by significant variability that may affect efficacy and tolerability. The aim of this review is to assess evidence that would justify therapeutic drug monitoring (TDM) and provide key information for the interpretation of erlotinib plasma concentrations. Literature was systematically reviewed to evaluate the standard criteria defining the potential clinical usefulness of TDM. Assessment was focused on the existence of unpredictable and wide PK variability and of consistent PK-pharmacodynamic relationships. PK parameters actually show marked variability (apparent clearance estimated to 4.85 ± 4.71 L/h, elimination half-life to 21.86 ± 28.35 hours, and apparent volume of distribution to 208 ± 133 L). Many covariates influence these parameters (CYP3A4 inducers or inhibitors, food, age, liver impairment), but most sources of variability still have to be identified. Some studies have demonstrated a relationship between exposure to erlotinib and clinical outcomes or skin toxicity. Erlotinib activity and target concentrations furthermore depend on tumor characteristics (eg, mutations on epidermal growth factor receptor and on K-ras). These results are in favor of TDM in addition to treatment adjustment for tumor biomarkers, but prospective clinical trials validating its clinical benefits are lacking. This review provides all the relevant information available to assist clinical interpretation of erlotinib plasma measurements. PK percentile curves and consideration to covariates yield information on whether a concentration measured is expected, whereas half maximal inhibitory concentration values determined in vitro provide preliminary insights on target concentration values to reach. Eventually, dosage adaptation might be considered in patients with intolerable toxicity because of excessive plasma levels or conversely nonresponse imputable to insufficient exposure.

Implication of hepatic transporters (MDR1 and MRP2) in inflammation-associated idiosyncratic drug-induced hepatotoxicity investigated by microvolume cytometry.

Idiosyncratic drug-induced hepatotoxicity accounts for about 13% of all cases of acute liver failure, therefore cited as the most frequent reason for post-marketing drug withdrawal. Despite this, the underlying mechanisms remain poorly understood due to lack in adequate screening assays and predictive in vitro models. Hepatic transporters play a crucial role in the absorption, distribution, and elimination of both endogenous substrates and xenobiotics. Defects in transporter function can lead to altered drug disposition, including toxicity and loss of efficacy. Inflammation is one condition for demonstrated variable drug response, attributed in part, to changes in function of drug transporters. The present study investigates the implication of two important hepatic transporters (MDR1 and MRP2) in idiosyncratic drug-induced hepatotoxicity in the presence and absence of an inflammatory context. The synergistic effect of idiosyncratic drugs (Trovafloxacin, nimesulide, telithromycin, and nefazodone) and inflammatory stimuli (TNF-α + LPS) on the efflux activity of hepatic transporters was studied using microvolume cytometry. Our results demonstrated on the one hand that both MDR1 and MRP2 are variably implicated in idiosyncratic drug-induced liver injury and on the other hand that the occurrence of an inflammatory reaction during idiosyncratic drug therapy can noticeably modulate this implication. In the absence of an inflammatory stress, none of the four tested drugs modulated the efflux activity of MRP2; nevertheless telithromycin and nefazodone inhibited the efflux activity of MDR1. Upon occurrence of an inflammatory stress, the inhibitory potential of trovafloxacin, nimesulide, and nefazodone on the efflux activity of MRP2 was noticeably revealed, while the telithromycin and nefazodone-induced inhibition of MDR1 was clearly attenuated. Knowledge of underlying mechanisms may significantly contribute to elimination of potential hepatotoxic drugs long before marketing and to prevention of drug-induced hepatotoxicity.

Adherence to recommendations for the use of antifungal agents in a tertiary care hospital.

OBJECTIVES: The aim of our study was to assess the adherence to labelling and international guidelines for antifungal prescribing. METHODS: A retrospective study was performed in intensive care units in addition to the oncology and haematology department, which covered 70% of antifungal consumption at Hautepierre Hospital, Strasbourg, France. On reviewing medical charts, the antifungal prescription was examined in relation to the recommendations of indication, dosage, risk of drug-drug interactions and, where appropriate, antifungal susceptibility testing. Treatments were considered appropriate, inappropriate or debatable. RESULTS: Between January and April 2007, 199 treatments were given for 179 different episodes in 133 adult patients. Treatments were prescribed for pre-emptive or targeted therapy (n = 90, with 60 for candidiasis, 26 for aspergillosis and 4 for other mould diseases), empirical therapy (n = 17) and primary (n = 81) or secondary (n = 11) prophylaxis. Fluconazole accounted for 67% of prescriptions, followed by voriconazole (19%), caspofungin (10%), posaconazole (2%), conventional or liposomal amphotericin B (2%), itraconazole (<1%) and terbinafine (<1%). Indication and dosage were found to be appropriate in 65% and 62% of cases, inappropriate in 22% and 21%, and debatable in 13% and 17%, respectively. The overall (by combining all assessment criteria) rate of inappropriate use was 40%. The overall survival rate at 12 weeks was highest in patients receiving appropriate therapy (81% versus 72% and 68% in the debatable and inappropriate therapy groups, respectively), with between-group differences not being significant (P = 0.49). CONCLUSIONS: Our evaluation revealed a high proportion of inappropriate or debatable use of antifungal agents, while highlighting significant issues, such as inadequate dosage or indications.

Characterization of post-surgical alterations in the bile duct-cannulated rat.

The bile duct-cannulated (BDC) rat is a standard animal model used in ADME experiments. The aim of this study was to investigate post-surgical alterations that are relevant to ADME investigations in BDC rats compared with sham- and non-operated animals. Water and food intake was reduced in the animals' post-surgery. This led to a lower body weight in operated animals. In BDC animals, aspartate aminotransferase (AST) levels in plasma were transiently elevated and total bile acid levels were reduced. Alpha(1)-acid glycoprotein (AGP) in plasma and the concentration of bile components in bile were elevated. Histopathology showed inflammation in the area of the cannulation between the liver and the small intestine. A microarray-based gene expression and RTq-PCR analysis identified altered expression for several genes involved in drug disposition including the down-regulation of cytochrome P450 enzymes. This led to reduced cytochrome P450 content in the liver and lower metabolic activity in microsomes from BDC and sham-operated rats compared with naïve animals. The results of the study suggest that the post-surgical inflammation leads to physiological changes relevant for drug absorption and disposition. These alterations should be accounted for in the interpretation of ADME studies in BDC animals.

The pharmacokinetics of ropivacaine after intraperitoneal administration: instillation versus nebulization.

BACKGROUND: Intraperitoneal local anesthetic administration provides perioperative analgesia during laparoscopic procedures. We compared the pharmacokinetics of intraperitoneal ropivacaine administered by instillation or nebulization. METHODS: A crossover study was performed on 5 pigs under standardized general anesthesia with a carbon dioxide pneumoperitoneum of 12 mm Hg for 1 hour. Each animal, acting as its own control, was studied twice with an 8-day interval and received, in a randomized sequence, 3 mg/kg ropivacaine either by intraperitoneal instillation at the time of pneumoperitoneum exsufflation or by continuous nebulization in the carbon dioxide insufflation tubing. Arterial blood samples were taken every 10 minutes up to 120 minutes, and then hourly up to 6 hours. Ropivacaine concentrations were measured using high-performance liquid chromatography with ultraviolet-visible detection. The plasma-free fraction was evaluated after plasma ultracentrifugation. Pharmacokinetic parameters were calculated using both noncompartmental and compartmental analysis. The mean values were compared using the Student t test, or Wilcoxon test for paired series. RESULTS: The data were described by a 1-compartment model for both ropivacaine administration techniques, with a delay of 10 minutes for the nebulization group. The maximal ropivacaine concentrations were 0.96 µg/mL for the nebulization group and 0.92 µg/mL for the instillation group (P = 0.66). The ropivacaine absorption constant was lower in the nebulization group (0.043 vs 0.083 min(-1), P = 0.02). There were no differences in the elimination half-life, elimination constant, mean total body clearance, distribution volume, mean area under the curve, and mean residence time. The free fraction of ropivacaine was also similar in the 2 groups. CONCLUSIONS: The pharmacokinetic profile of ropivacaine nebulization is similar to direct intraperitoneal instillation, but with a lower absorption rate.

Quercetin potentializes the respective cytotoxic activity of gemcitabine or doxorubicin on 3D culture of AsPC-1 or HepG2 cells, through the inhibition of HIF-1α and MDR1.

The impact of cancer on lifespan is significantly increasing worldwide. Enhanced activity of drug efflux pumps and the incidences of the tumor microenvironment such as the apparition of a hypoxic gradient inside of the bulk tumor, are the major causes of chemotherapy failure. For instance, expression of Hypoxia-inducible factor (HIF-1α) has been associated with metastasis, resistance to chemotherapy and reduced survival rate. One of the current challenges to fight against cancer is therefore to find new molecules with therapeutic potential that could overcome this chemoresistance. In the present study, we focused on the bioactive plant flavonoid quercetin, which has strong antioxidant and anti-proliferative properties. We examined the efficacy of combined treatments of quercetin and the anti-cancer drugs gemcitabine and doxorubicin, known to specifically act on human pancreatic and hepatic cancer cells, respectively. Moreover, our study aimed to investigate more in-depth the implication of the multidrug transporter MDR1 and HIF-1α n chemoresistance and if quercetin could act on the activity of the drug efflux pumps and the hypoxia-associated effects. We observed that the anti-cancer drugs, were more effective when administered in combination with quercetin, as shown by an increased percentage of dead cells up to 60% in both 2D and 3D cultures. In addition, our results indicated that the combination of anti-cancer drugs and quercetin down-regulated the expression of HIF-1α and increased the expression levels of the regulator of apoptosis p53. Moreover, we observed that quercetin could inhibit the efflux activity of MDR1. Finally, our in vitro study suggests that the efficiency of the chemotherapeutic activity of known anti-cancer drugs might be significantly increased upon combination with quercetin. This flavonoid may therefore be a promising pharmacological agent for novel combination therapy since it potentializes the cytotoxic activity of gemcitabine and doxorubicin on by targeting the chemoresistance developed by the pancreatic and liver cancer cells respectively.

Flavagline synthetic derivative induces senescence in glioblastoma cancer cells without being toxic to healthy astrocytes.

Glioblastoma (GBM) is one of the most aggressive types of cancer, which begins within the brain. It is the most invasive type of glioma developed from astrocytes. Until today, Temozolomide (TMZ) is the only standard chemotherapy for patients with GBM. Even though chemotherapy extends the survival of patients, there are many undesirable side effects, and most cases show resistance to TMZ. FL3 is a synthetic flavagline which displays potent anticancer activities, and is known to inhibit cell proliferation, by provoking cell cycle arrest, and leads to apoptosis in a lot of cancer cell lines. However, the effect of FL3 in glioblastoma cancer cells has not yet been examined. Hypoxia is a major problem for patients with GBM, resulting in tumor resistance and aggressiveness. In this study, we explore the effect of FL3 in glioblastoma cells under normoxia and hypoxia conditions. Our results clearly indicate that this synthetic flavagline inhibits cell proliferation and induced senescence in glioblastoma cells cultured under both conditions. In addition, FL3 treatment had no effect on human brain astrocytes. These findings support the notion that the FL3 molecule could be used in combination with other chemotherapeutic agents or other therapies in glioblastoma treatments.

Drug-drug interactions of triazole antifungal agents in multimorbid patients and implications for patient care.

Drug interactions occur frequently with triazole antifungal agents because of their properties as inhibitors of 1 or more phase 1 (cytochrome P450) biotransformation enzymes and, possibly, as inhibitors or substrates of a phase 2 biotransformation enzyme or transporter protein. Multimorbid patients, including those with hematologic malignancies or other cancers, hematopoietic stem cell or organ transplant recipients, patients infected with the human immunodeficiency virus, and those in the intensive care unit, are at increased risk for drug interactions because they typically require several concomitant medications. They may also be extremely vulnerable to the clinical signs and symptoms of drug interactions. This review describes clinically significant drug interactions most frequently seen in multimorbid patients who receive systemic therapy with triazole antifungals for the prophylaxis or treatment of invasive fungal infections; including interactions with corticosteroids, immunosuppressants, anti-infective drugs, benzodiazepines, opioid analgesics, statins, anticoagulants, anticonvulsants, and drugs affecting gastric pH. The review also describes recommendations concerning contraindications and dose-modification strategies. The azoles differ markedly in their pharmacokinetic and antifungal properties, safety and tolerability, and drug-interaction profiles. Many drug interactions can be prevented if clinicians are thoroughly familiar with the pharmacokinetic profiles of different azoles, follow contraindications and dose-modification recommendations, and switch azoles when possible to achieve the best combination of clinical efficacy and safety. Therapeutic drug monitoring can help optimize treatment and prevent underdosing or overdosing of drugs. Education of patients and their families about signs and symptoms of possible drug interactions is also beneficial.

The enzymatic basis of drug-drug interactions with systemic triazole antifungals.

Drug-drug interactions are a recurring problem in immunocompromised patients treated with triazole antifungals. While the introduction of new antifungals has expanded opportunities for lowering drug toxicity, virtually all antifungal regimens carry the risk of pharmacokinetic and pharmacodynamic interaction. This review presents the published data on molecular determinants (enzymes, transporters, orphan nuclear receptors) of systemic triazole pharmacokinetics in humans, including itraconazole, fluconazole, voriconazole and posaconazole. Systemic triazoles are inhibitors of cytochrome P450 (CYP) isozymes, such as CYP3A4, CYP2C9 and CYP2C19, to varying degrees. In addition, some are substrates and/or inhibitors of drug transporters such as multidrug resistance-1 gene product, P-glycoprotein, or breast cancer resistance protein. The interactions of triazole antifungals can be divided into the following categories: modifications of antifungal pharmacokinetics by other drugs, modifications of other drug pharmacokinetics by antifungals, and two-way interactions. These features are the basis of most interactions that occur during triazole therapy.

A UV-Raman spectrometry method for quality control of anticancer preparations: Results after 18 months of implementation in hospital pharmacy.

In France, chemotherapy preparation units of hospital pharmacy compound cytotoxic infusion bags adapted to each patient. The narrow therapeutic index of these preparations led us to implement qualitative and quantitative control for patients' safety. To this aim, we calibrated an equipment combining UV-vis spectrometry and Raman spectroscopy (QC Prep+) and monitored 14 different molecule-solvent combinations over a 18 months period. This rapid and specific method allowed the qualitative and quantitative analysis of 1 mL sample tests in less than 2 min. On 5742 anticancer preparations, we obtained accepted results with more than 99.4% solvent identification, 99.6% drug identification and only 1.52% of preparations not matching quantitative specifications (±15% of theoretical concentration). This quantitative control enabled us to pinpoint some critical points of production for two of the most common preparations. We thus updated the procedures of reconstitution and preparation, increasing the quality of final product. UV-Raman spectrometry is thus an effective tool to control chemotherapy infusions and to improve good practices of preparation.