BackgroundCancer stem cells (CSCs) are considered the cell subpopulation responsible for breast cancer (BC) initiation, growth, and relapse. CSCs are identified as self-renewing and tumor-initiating cells, conferring resistance to chemo- and radio-therapy to several neoplasias. Nowadays, th (about 10mM)e pharmacological targeting of CSCs is considered an ineludible therapeutic goal. The antidiabetic drug metformin was reported to suppress in vitro and in vivo CSC survival in different tumors and, in particular, in BC preclinical models. However, few studies are available on primary CSC cultures derived from human postsurgical BC samples, likely because of the limited amount of tissue available after surgery. In this context, comparative oncology is acquiring a relevant role in cancer research, allowing the analysis of larger samples from spontaneous pet tumors that represent optimal models for human cancer.MethodsIsolation of primary canine mammary carcinoma (CMC) cells and enrichment in stem-like cell was carried out from fresh tumor specimens by culturing cells in stem-permissive conditions. Phenotypic and functional characterization of CMC-derived stem cells was performed in vitro, by assessment of self-renewal, long-lasting proliferation, marker expression, and drug sensitivity, and in vivo, by tumorigenicity experiments. Corresponding cultures of differentiated CMC cells were used as internal reference. Metformin efficacy on CMC stem cell viability was analyzed both in vitro and in vivo.ResultsWe identified a subpopulation of CMC cells showing human breast CSC features, including expression of specific markers (i.e. CD44, CXCR4), growth as mammospheres, and tumor-initiation in mice. These cells show resistance to doxorubicin but were highly sensitive to metformin in vitro. Finally, in vivo metformin administration significantly impaired CMC growth in NOD-SCID mice, associated with a significant depletion of CSCs.ConclusionsSimilarly to the human counterpart, CMCs contain stem-like subpopulations representing, in a comparative oncology context, a valuable translational model for human BC, and, in particular, to predict the efficacy of antitumor drugs. Moreover, metformin represents a potential CSC-selective drug for BC, as effective (neo-)adjuvant therapy to eradicate CSC in mammary carcinomas of humans and animals.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1235-8) contains supplementary material, which is available to authorized users.

Several factors may influence meropenem pharmacokinetics in ICU patients. Continuous i.v. infusions of meropenem seem to be more effective than standard regimens to achieve optimal therapeutic targets.

Pharmacokinetics and dose-finding studies on sorafenib were conducted on heterogeneous groups of patients with solid tumors. Portal hypertension, gut motility impairment and altered bile enterohepatic circulation may explain different sorafenib toxicological profile in cirrhotic patients. This study evaluated sorafenib plasma concentration in a homogeneous group of cirrhotic patients with hepatocellular carcinoma (HCC). Sorafenib concentrations were determined by liquid chromatography in 12 consecutive patients. Data have been evaluated by the generalized estimating equations method (p value statistical level was set at α = 0.05). (1) There were not significant differences between sorafenib concentrations in patients who tolerate the full dose versus patients with reduced dose due to toxicity; (2) the average sorafenib concentrations measured 3 h after the morning dosing were lower than those measured 12 h after the evening dosing (p = 0.005); (3) sorafenib concentrations decrease overtime (p < 10(-4)); (4) it has been found an association between the development of severe adverse reactions and sorafenib concentrations (p < 10(-5)). The relationship between dose and concentration of sorafenib in HCC patients is poor and not clinically predictable, confirming the variability both in the maximum tolerated dose and in plasma concentrations. Several factors may influence the pharmacokinetics in patients with liver disease. This may explain the inter-patient variability of concentrations and the lack of differences in concentration at different dosages. It could be interesting to extend the series of HCC patients to enhance information on the kinetics of the drug; furthermore, to establish a threshold of plasma sorafenib concentrations to predict severe adverse reactions would be clinically useful.

Metformin is an antidiabetic drug which possesses antiproliferative activity in cancer cells when administered at high doses, due to its unfavorable pharmacokinetics. The aim of this work was to develop a pharmacological tool for the release of metformin in proximity of the tumor, allowing high local concentrations, and to demonstrate the in vivo antitumor efficacy after a prolonged metformin exposition. A 1.2% w/w metformin thermoresponsive parenteral formulation based on poloxamers P407 and P124, injectable at room temperature and undergoing a sol-gel transition at body temperature, has been developed and optimized for rheological, thermal and release control properties; the formulation is easily scalable, and proved to be stable during a 1-month storage at 5 °C. Using NOD/SCID mice pseudo-orthotopically grafted with MDA-MB-231/luc+ human breast cancer cells, we report that multiple administrations of 100 mg of the optimized metformin formulation close to the tumor site cause tissue accumulation of the drug at levels significantly higher than those observed in plasma, and enough to exert antiproliferative and pro-apoptotic activities. Our results demonstrate that this formulation is endowed with good stability, tolerability, thermal and rheological properties, representing a novel tool to be pursued in further investigations for adjuvant cancer treatment.

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Aim: Monitoring of blood levels of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) is necessary for optimization of administration of medical cannabis. We describe the validation of a ultra-HPLC–MS/MS method for quantifying THC and CBD from plasma and decoctions and its application for therapeutic drug monitoring.Materials & methods: Analyses were performed by using a TSQ Quantiva™ Triple Quadrupole coupled to a Ultimate 3000 UHPLC system with atmospheric pressure chemical ionization after sample preparation with a straightforward method with deuterated internal standards. Results: The method has been validated following EMA guidelines and is linear in plasma from 0.16 to 10 ng/ml for both THC and CBD and in decoctions from 4.7 to 600 ng/ml. Conclusion: Given the unpredictable pharmacokinetic behavior of THC and CBD in patients, monitoring of plasma concentrations is strongly recommended for patients under treatment with medical cannabis.

The objective of this study was to assess the achievement of pharmacokinetic/pharmacodynamic (PK/PD) targets of meropenem (MEM) in critically-ill patients with bloodstream infections (BSI) due to Klebsiella pneumoniae-carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) with MEM minimum inhibitory concentrations (MICs) ≥16 mg/L. Nineteen critically-ill patients with KPC-Kp BSI were given combination therapy including MEM, tigecycline, plus colistin or gentamicin (according to susceptibility testing). MEM was administered as an extended 3-hour infusion of 2 g every 8 hours, or adjusted according to renal function. MEM plasma concentrations were determined by high-performance liquid chromatography. PK/PD targets for MEM were defined as T > 40% 1×MIC and T > 40% 4×MIC. Possible synergisms between MEM and coadministered agents were assessed by time-kill assays based on plasma levels for MEM and on fixed plasma concentrations for the other agents. In none of 19 patients MEM reached any PK/PD target. The actual MEM MICs were 256, 512, and 1024 mg/L in 1, 3, and 15 isolates, respectively. However, theoretically, the PK/PD target of T > 40% 1×MIC could have been achieved in 95%, 68%, 32% and 0% of the isolates for MIC equal to 8, 16, 32, and 64 mg/L, respectively. No synergisms were observed between MEM and coadministered agents. In conclusion, high-dose MEM failed to reach PK/PD targets in 19 patients with BSI due to KPC-Kp with very high MEM MICs. On a theoretical basis, our results suggest a possible usefulness of MEM against resistant blood isolates with MICs up to 32 mg/L.

The results could indicate that a higher plasma DFX concentration could be associated with greater chelation efficacy. As a correlation between dose and CDFX was not demonstrated, it seems useful to monitor the concentrations to optimize and determine the most appropriate dose for each patient. Interesting results emerged from the analysis of genetic and physical characteristics of patients: LBM was a borderline significant effect modifier of the relationship between UGT1A1 polymorphisms and CDFX . Individual patient-tailored dosing of DFX should help to improve iron chelation efficacy and to reduce dose-dependent drug toxicity.