Glycemic control and cancer outcomes in oncologic patients with diabetes: an Italian Association of Medical Oncology (AIOM), Italian Association of Medical Diabetologists (AMD), Italian Society of Diabetology (SID), Italian Society of Endocrinology (SIE), Italian Society of Pharmacology (SIF) multidisciplinary critical view.

BACKGROUND:  Increasing evidence suggests that diabetes increases the risk of developing different types of cancer. Hyperinsulinemia, hyperglycemia and chronic inflammation, characteristic of diabetes, could represent possible mechanisms involved in cancer development in diabetic patients. At the same time, cancer increases the risk of developing new-onset diabetes, mainly caused by the use of specific anticancer therapies. Of note, diabetes has been associated with a ∼10% increase in mortality for all cancers in comparison with subjects who did not have diabetes. Diabetes is associated with a worse prognosis in patients with cancer, and more recent findings suggest a key role for poor glycemic control in this regard. Nevertheless, the association between glycemic control and cancer outcomes in oncologic patients with diabetes remains unsettled and poorly debated. PURPOSE:  The current review seeks to summarize the available evidence on the effect of glycemic control on cancer outcomes, as well as on the possibility that timely treatment of hyperglycemia and improved glycemic control in patients with cancer and diabetes may favorably affect cancer outcomes.

MiRNA dysregulation underlying common pathways in type 2 diabetes and cancer development: an Italian Association of Medical Oncology (AIOM)/Italian Association of Medical Diabetologists (AMD)/Italian Society of Diabetology (SID)/Italian Society of Endocrinology (SIE)/Italian Society of Pharmacology (SIF) multidisciplinary critical view.

Increasing evidence suggests that patients with diabetes, particularly type 2 diabetes (T2D), are characterized by an increased risk of developing different types of cancer, so cancer could be proposed as a new T2D-related complication. On the other hand, cancer may also increase the risk of developing new-onset diabetes, mainly caused by anticancer therapies. Hyperinsulinemia, hyperglycemia, and chronic inflammation typical of T2D could represent possible mechanisms involved in cancer development in diabetic patients. MicroRNAs (miRNAs) are a subset of non-coding RNAs, ⁓22 nucleotides in length, which control the post-transcriptional regulation of gene expression through both translational repression and messenger RNA degradation. Of note, miRNAs have multiple target genes and alteration of their expression has been reported in multiple diseases, including T2D and cancer. Accordingly, specific miRNA-regulated pathways are involved in the pathogenesis of both conditions. In this review, a panel of experts from the Italian Association of Medical Oncology (AIOM), Italian Association of Medical Diabetologists (AMD), Italian Society of Diabetology (SID), Italian Society of Endocrinology (SIE), and Italian Society of Pharmacology (SIF) provide a critical view of the evidence about the involvement of miRNAs in the pathophysiology of both T2D and cancer, trying to identify the shared miRNA signature and pathways able to explain the strong correlation between the two conditions, as well as to envision new common pharmacological approaches.

Diabetes management in cancer patients. An Italian Association of Medical Oncology, Italian Association of Medical Diabetologists, Italian Society of Diabetology, Italian Society of Endocrinology and Italian Society of Pharmacology multidisciplinary consensus position paper.

Cancer management has significantly evolved in recent years, focusing on a multidisciplinary team approach to provide the best possible patient care and address the various comorbidities, toxicities, and complications that may arise during the patient's treatment journey. The co-occurrence of diabetes and cancer presents a significant challenge for health care professionals worldwide. Management of these conditions requires a holistic approach to improve patients' overall health, treatment outcomes, and quality of life, preventing diabetes complications and cancer treatment side-effects. In this article, a multidisciplinary panel of experts from different Italian scientific societies provide a critical overview of the co-management of cancer and diabetes, with an increasing focus on identifying a novel specialty field, 'diabeto-oncology', and suggest new co-management models of cancer patients with diabetes to improve their care. To better support cancer patients with diabetes and ensure high levels of coordinated care between oncologists and diabetologists, 'diabeto-oncology' could represent a new specialized field that combines specific expertise, skills, and training.

Druggable targets meet oncogenic drivers: opportunities and limitations of target-based classification of tumors and the role of Molecular Tumor Boards.

The therapeutic landscape of cancer is changing rapidly due to the growing number of approved drugs capable of targeting specific genetic alterations. This aspect, together with the development of noninvasive methods for the assessment of somatic mutations in the peripheral blood of patients, generated a growing interest toward a new tumor-agnostic classification system based on 'predictive' biomarkers. The current review article discusses this emerging alternative approach to the classification of cancer and its implications for the selection of treatments. It is suggested that different types of cancers sharing the same molecular profiles could benefit from the same targeted drugs. Although recent clinical trials have demonstrated that this approach cannot be generalized, there are also specific examples that demonstrate the clinical utility of this alternative vision. In this rapidly evolving scenario, a multidisciplinary approach managed by institutional Molecular Tumor Boards is fundamental to interpret the biological and clinical relevance of genetic alterations and the complexity of their relationship with treatment response.

Drug-drug interactions between palbociclib and proton pump inhibitors may significantly affect clinical outcome of metastatic breast cancer patients.

BACKGROUND: Proton-pump-inhibitors (PPIs) are frequently prescribed for the management of anticancer drug-related gastrointestinal symptoms. Palbociclib is a weak base with pH-dependent solubility and potential drug-drug interaction at the absorption level may affect clinical pharmacokinetics. The current study was aimed at investigating the effect of co-administration of PPIs and palbociclib on progression-free survival (PFS) in metastatic breast cancer (mBC) patients. PATIENTS AND METHODS: Patients affected by estrogen receptor-positive, human epidermal growth factor receptor 2-negative mBC, who were candidates for first-line treatment with palbociclib, were enrolled in this retrospective observational study. Patients were defined as 'no concomitant PPIs' if no PPIs were administered during palbociclib treatment, and as 'concomitant PPIs' if the administration of PPIs covered the entire or not less than two-thirds of treatment with palbociclib. All clinical interventions were made according to clinical practice. RESULTS: A total of 112 patients were enrolled in the study; 56 belonged to the 'no concomitant PPIs' group and 56 to the 'concomitant PPIs' group. Seventy-one patients were endocrine-sensitive and received palbociclib and letrozole, and 43 were endocrine-resistant and were treated with palbociclib and fulvestrant. The most prescribed PPI was lansoprazole. Patients taking PPIs had a shorter PFS than those taking palbociclib and endocrine therapy alone (14.0 versus 37.9 months, P < 0.0001). Multivariate analysis confirmed concomitant PPIs as the only independent predictive factor for shorter PFS (P = 0.0002). PFS was significantly longer in estrogen-sensitive mBC with no concomitant PPIs compared with patients taking PPIs or estrogen-resistant patients, with and without PPIs (P < 0.0001). No correlation with adverse events was found when considering grade >2 hematological toxicities [Common Terminology Criteria for Adverse Events (CTCAE) scale]. CONCLUSIONS: The present study demonstrates that concomitant use of PPIs in mBC patients treated with palbociclib has a detrimental effect on PFS. Therefore, it is recommended to prescribe PPIs with caution in these patients, strictly adhering to the indications in the summary of product characteristics (RCP).

Cytotoxic effects of Echinacea root hexanic extracts on human cancer cell lines.

Echinacea is one of the most widely used alternative medicine in the world. Intake of Echinacea preparations is common among patients with advanced malignancies enrolled onto phase I chemotherapy trials; however, to our knowledge, no data are available regarding the possible direct effect of Echinacea species on human cancer cells. The purpose of the present study was to investigate potential in vitro cytotoxic and pro-apoptotic properties of hexanic root extract of the three medicinal Echinacea (Asteraceae) species (Echinacea pallida (Nutt.) Nutt., Echinacea angustifolia DC. var. angustifolia, Echinacea purpurea (L.) Moench.) on the human pancreatic cancer MIA PaCa-2 and colon cancer COLO320 cell lines. We demonstrated, for the first time, that all the three species reduced cell viability in a concentration- and time-dependent manner; Echinacea pallida was the most active species with IC(50)s of 46.41+/-0.87 and 10.55+/-0.70 microg/ml in MIA PaCa-2 and COLO320 cells, respectively. Echinacea pallida extract was able to induce apoptosis by increasing significantly caspase 3/7 activity and promoting nuclear DNA fragmentation. These results represent the starting point to establish viable scientific evidence on the possible role of Echinacea species in medical oncology.

Pharmacogenetic determinants of anti-cancer drug activity and toxicity.

Cellular responses to anti-cancer agents result from the interaction between drugs, cellular targets and mechanisms of damage repair. Despite the pharmacological advances in the treatment of cancer, the clinical efficacy of chemotherapy is unpredictable in most patients. However, new information on the genetics of cancer delineates strategies by which the genetic background of tumour cells and patients might be profiled to select anti-cancer agents with improved efficacy and tolerability. This article focuses on the application of pharmacogenetics in the characterization of differences in the pharmacokinetics and pharmacodynamics of anti-cancer agents among individuals to define the likelihood of response and reduce the incidence of adverse effects.

The gemcitabine/epirubicin/paclitaxel combination in advanced breast cancer.

The purpose of this study was to determine the response rate of the gemcitabine/epirubicin/paclitaxel combination (GET) and its feasibility as induction chemotherapy before high-dose consolidation treatment in patients with metastatic breast cancer. Patients received gemcitabine 1,000 mg/m2 on days I and 4, epirubicin 90 mg/m2 on day 1, and paclitaxel 175 mg/m2 on day I every 3 weeks for up to eight courses. After six courses of GET, responding patients or those with stable disease entered a high-dose chemotherapy program. All 36 enrolled patients were evaluated for toxicity and response. The GET combination was well tolerated, with myelosuppression the being most common toxicity; grade 4 neutropenia was reported in 56% of patients. The overall response rate was 89% (95% confidence interval, 73.4% to 96.9%), with a 28% complete response rate. The high-dose chemotherapy program resulted in a response rate of 92% and a complete response rate of 44%. As a result of the promising activity demonstrated in this phase II study with GET and following high-dose chemotherapy, three related studies are planned: an in vitro study evaluating the possible synergism of paclitaxel and gemcitabine, a phase III study comparing GET with epirubicin/paclitaxel in metastatic breast cancer, and a phase II trial evaluating GET in patients with operable breast cancer.

Design, synthesis, and characterization of the antitumor activity of novel ceramide analogues.

A deficiency in apoptosis is one of the key events in the proliferation and resistance of malignant cells to antitumor agents; for these reasons, the search for apoptosis-inducing drugs represents a valuable approach for the development of novel anticancer therapies. In this study we report the first example of conformationally restrained analogues of ceramide (compounds 1-4), where the polar portion of the molecule has been replaced by a thiouracil (1, 3) or uracil (2, 4) ring. The evaluation of their biologic activity on CCRF-CEM human leukemia cells demonstrated that the most active was compound 1 followed by compound 2 (mean 50% inhibition of cell proliferation [IC(50)] 1.7 and 7.9 microM, respectively), while compounds 3 and 4 were inactive, as were uracil, thiouracil, and 5,6-dimethyluracil, the pyrimidine moieties of compounds 1-4. For comparison, the IC(50) of the reference substance, the cell-permeable C2-ceramide, was 31.6 microM. Compounds 1 and 2 and C2-ceramide were able to trigger apoptosis, as shown by the occurrence of DNA and nuclear fragmentation, and to release cytochrome c from treated cells. The treatment of female CD-1 nu/nu athymic mice bearing a WiDr human colon xenograft with the most active compound 1 at 2, 10, 50, and 200 mg/kg ip daily for 10 days resulted in an antitumor effect that was equivalent at 50 mg/kg or superior (200 mg/kg) to that of cyclophosphamide, 20 mg/kg ip daily, delivered on the same schedule, with markedly lower systemic toxicity. In conclusion, the present study demonstrates that the new ceramide analogues 1 and 2 are characterized by in vitro and in vivo antitumor activity and low toxicity.

High-dose consolidation chemotherapy with Idarubicin and alkylating agents following induction with gemcitabine-epirubicin-paclitaxel in metastatic breast cancer: a dose finding study.

Preliminary randomized studies have failed to show a survival benefit of high-dose chemotherapy with alkylators in advanced breast cancer. Idarubicin is an active agent in breast cancer and is suitable for dose escalation. We designed a dose finding study with escalating high-dose idarubicin (HD-Ida) followed by fixed high-dose thiotepa+melphalan (HD-TM) with peripheral blood progenitor cells (PBPC) in MBC patients with stable disease or in partial response after six courses of induction chemotherapy with gemcitabine 1000 mg/m(2) days 1 and 4, epirubicin 90 mg/m(2) day 1, taxol 175 mg/m(2) day 1 (GET). Aims of the study were to identify the maximum tolerated dose (MTD) of idarubicin, to evaluate the cardiac safety and activity of HD-Ida and HD-TM after GET and to study the pharmacokinetic profile of idarubicin and idarubicinol. A total of 14 patients were treated. Idarubicin was administered as a 48 h continuous i.v. infusion at the following dose levels: 40 mg/m(2) (three patients), 50 mg/m(2) (three patients), 60 mg/m(2) (five patients) and 70 mg/m(2) (three patients). Mucositis was the dose-limiting toxicity and the MTD was 60 mg/m(2). C(max) of Idarubicin and idarubicinol were 7.7+/-2.0 and 26.3+/-9.7 ng/ml at 40 mg/m(2) and increased to 14.8+3.0 and 47.4+12.6 ng/ml at 70 mg/m(2). AUCt(0-264) of idarubicin and idarubicinol increased from 423.2+/-111.6 and 2581+/-606 hng/ml at 40 mg/m(2) to 732.8+/-140.2 and 4590+/-1258 hng/ml at 70 mg/m(2). Conversion rates after HD-Ida and HD-TM were 28.6 and 38.5%, respectively. No episodes of cardiac toxicity were observed. We conclude that HD-Ida followed by HD-TM is feasible and devoid of cardiac toxicity. Moreover, the activity of HD-Ida after a epirubicin-containing regimen suggests incomplete cross-resistance between the two drugs.

Inhibitory effect of suramin in rat models of angiogenesis in vitro and in vivo.

The aim of the present study was to test the ability of the chemotherapeutic agent suramin to inhibit angiogenesis in experimental models in vitro and in vivo. In the culture of rat aortic rings on fibronectin, suramin dose-dependently inhibited vascular cell growth, achieving the maximal effect (mean - 88% versus controls, P < 0.05) at 400 microg/ml. Image analysis showed that suramin could inhibit microvessel sprouting in fibrin from rat aortic rings as evaluated by the ratio between the cellular area and the mean gray value of the sample (sprouting index); suramin at 50 microg/ml significantly reduced the sprouting index from the control value of 0.35+/-0.04 to 0.14+/-0.02 mm2/gray level (P < 0.05). Likewise, the area occupied by cells was 19.2+/-1.8 mm2 as compared with 41.8+/-4.2 mm2 in controls (P < 0.05). In the rat model of neovascularization induced in the cornea by chemical injury, suramin at 1.6 mg/eye per day reduced the length of blood vessels (0.7+/-0.1 mm as compared with 1.5+/-0.1 mm in controls, P < 0.05). In the same model the ratio between the area of blood vessels and the total area of the cornea (area fraction score) was decreased by suramin from 0.19+/-0.02 in controls to 0.03+/-0.003 (P < 0.05). Suramin given i.p. at 30 mg/ kg per day markedly inhibited the neovascularization induced in the rat mesentery by compound 48/80 or conditioned medium from cells secreting the angiogenic protein fibroblast growth factor-3 (FGF-3). The area fraction score in control rats treated with compound 48/80 was 0.31+/-0.03, and this was reduced to 0.07+/-0.01 by suramin (P < 0.05). After i.p. administration of FGF-3 the area fraction score was reduced by suramin from 0.29+/-0.03 to 0.05+/-0.01 (P < 0.05). These results provide evidence that suramin exerts inhibitory effects on angiogenesis in both in vitro and in vivo models.

Metabolism of 6-mercaptopurine in the erythrocytes, liver, and kidney of rats during multiple-dose regimens.

PURPOSE: To describe the metabolism of 6-mercaptopurine (6-MP) in erythrocytes and tissues of rats after repeated administration of 6-MP at two dose levels and to provide evidence that in vivo modulation of 6-MP anabolism can be obtained by simultaneous treatment with ribavirin or hydroxyurea, two inhibitors of enzymes involved in the bioactivation of 6-MP to the active 6-thioguanine nucleotides (6-TGN). METHODS: Rats were treated i.p. with 6-MP at 12.5 and 25 mg/kg daily for 12 days and erythrocyte, liver, and kidney levels of 6-mercaptopurine nucleotides (6-MPN) and 6-TGN were investigated during the accumulation phase and for 50 days after the end of treatment. In combination studies, ribavirin at 75 and 100 mg/kg per day (for 6-MP, 25 and 12.5 mg/kg per day) or hydroxyurea at 200 mg/kg per day were given i.p. for 12 days. The measurements of thionucleotide levels in rat samples were performed by high-pressure liquid chromatography (HPLC). RESULTS: The maximal concentration (Cmax) and the area under the concentration versus time curve (AUC) of 6-MPN and 6-TGN in erythrocytes and tissues increased significantly after the administration of 6-MP at 25 mg/kg per day as compared with 12.5 mg/kg per day. In particular, the Cmax and AUC of 6-TGN in erythrocytes of rats treated with 6-MP at 25 mg/kg per day were approximately 5-fold higher than the 6-TGN values observed following treatment at 12.5 mg/kg per day. Moreover, 6-TGN levels in erythrocytes were significantly higher than those of 6-MPN (910.9+/-53.1 and 286.8+/-23.4 pmol/8 x 10(8) cells for 6-TGN and 6-MPN, respectively, P < 0.05) after treatment with 6-MP at 25 mg/kg per day. The administration of ribavirin, an inhibitor of inosine monophosphate dehydrogenase, in association with 6-MP increased the amount of 6-MPN detected in erythrocytes and tissues while reducing 6-TGN levels in samples. The production and accumulation of 6-MPN and 6-TGN were increased in erythrocytes and tissues by hydroxyurea, an inhibitor of ribonucleotide reductase. Finally, a significant correlation between thionucleotide concentrations and erythrocyte counts was observed. CONCLUSION: The overall results demonstrate that 6-MP is actively metabolized in rats and that its biotransformation can be modulated by agents acting on enzymes of the purine metabolism, resulting in significant changes in erythrocyte and tissue levels of 6-MPN and 6-TGN. These findings provide evidence that the rat is a suitable model for investigation of the metabolism of 6-MP and its possible pharmacologic modulation.

Chronic administration of suramin induces neurotoxicity in rats.

In the present study, the ability of suramin 18 mg/kg i.p. twice a week to induce chronic neurotoxicity in rats was investigated. After 20 weeks of suramin treatment, morphological analysis of nerve fibers demonstrated that 57.7+/-3.2% of them presented vesicular disruption of myelin sheaths; their thickness was 0.23+/-0.07 microm in suramin-treated rats with respect to 0.43+/-0.07 microm of controls (P<0.05). To investigate the interaction between suramin and nerve tissue, the binding of the drug to partially purified myelin P0 protein obtained from sciatic nerves was analysed. The percentage of suramin bound to rat myelin P0 protein was 94.0+/-9.5%; this value was decreased to 55.0+/-7.6% when heparan sulfate was added to the myelin protein suspension before suramin. The analysis of tissue drug concentrations at 5, 10 and 20 weeks of treatment showed that suramin accumulated into the sciatic nerve in a time-dependent fashion (130.8+/-18.1, 219.7+/-17.1 and 449.3+/-15.6 microg/g of tissue, respectively). In conclusion, suramin induces a chronic peripheral neurotoxicity in rats characterized by myelin damage and high tissue levels of the drug. The high affinity of suramin for partially purified myelin P0 protein suggests a possible mechanism for drug-induced toxicity.

Reed (Phragmites australis) decline in a brackish wetland in Italy.

A comparative field study was carried out at two sites (a healthy site and a declining site) in a brackish wetland in northern Italy, with the objective to investigate the symptoms and the possible causes leading to reed (Phragmites australis) decline in this area. The declining reed plants presented many of the symptoms (clumping habit, smaller size, weaker culms, abnormal rhizome and root anatomy, low starch levels in rhizomes) comprised within the so-called reed die-back syndrome, frequently observed in central European wetlands but never recorded previously in (Sub)Mediterranean regions. Soil nutrient levels did not differ much between the two sites, with nitrate concentrations in the soil being even higher at the healthy site (1.54 microg g(-1); die-back site 0.76 microg g(-1)). Hence, eutrophication did not seem to represent a major cause in determining reed decline in this area. High sulphate concentrations in saltwater associated with low soil redox potentials (-215 mV) due to waterlogging resulted in high soil sulphide concentrations. Concentrations of organic acids, especially acetic acid, did not differ remarkably between sites. High sulphide levels presumably accounted for abnormal anatomical formations (callus blocking aerenchyma channels), lower rates of net CO2 exchange and reduced reserve storage, observed at the die-back site. This was associated with a lower mechanical resistance of reed culms which accelerated reed mortality in the die-back areas. We concluded that high sulpihde levels in permanently waterlogged soils may result in die-back of reed stands in Mediterranean wetlands.

Synergistic interaction between PPAR ligands and salbutamol on human bronchial smooth muscle cell proliferation.

BACKGROUND AND PURPOSE: An important objective in asthma therapy is to prevent the accelerated growth of airway smooth muscle cells which leads to hyperplasia and bronchial hyperreactivity. We investigated the effect of combination of salbutamol and PPARγ agonists on growth factor-stimulated human bronchial smooth muscle cell (BSMC) proliferation. EXPERIMENTAL APPROACH: Synergism was quantified by the combination index-isobologram method. Assays used here included analyses of growth inhibition, cell viability, DNA fragmentation, gene transcription, cell cycle and protein expression. KEY RESULTS: The PPARγ gene was highly expressed in BSMC and the protein was identified in cell nuclei. Single-agent salbutamol or PPARγ agonists prevented growth factor-induced human BSMC proliferation within a micromolar range of concentrations through their specific receptor subtypes. Sub-micromolar levels of combined salbutamol-PPARγ agonist inhibited growth by 50% at concentrations from ∼2 to 12-fold lower than those required for each drug alone, without induction of apoptosis or necrosis. Combination treatments also promoted cell cycle arrest at the G1/S transition phase and inhibition of ERK phosphorylation. CONCLUSIONS AND IMPLICATIONS: The synergistic interaction between PPARγ agonists and ß(2) -adrenoceptor agonists on airway smooth muscle cell proliferation highlights the anti-remodelling potential of this combination in chronic lung diseases.

Gemcitabine, epirubicin and paclitaxel: pharmacokinetic and pharmacodynamic interactions in advanced breast cancer.

BACKGROUND: The objectives of this study were to investigate the disposition of gemcitabine, epirubicin, paclitaxel, 2',2'-difluorodeoxyuridine and epirubicinol, and characterize the pharmacokinetic and pharmacodynamic profile of treatment in patients with breast cancer. PATIENTS AND METHODS: The drug dispostion in 15 patients who received gemcitabine 1000 mg/m2, epirubicin 90 mg/m2 and paclitaxel 175 mg/m2 (GEP) on day 1 of a 21-day cycle, was compared with that of patients treated with epirubicin 90 mg/m2 and paclitaxel 175 mg/m2 (EP, n = 6) and epirubicin 90 mg/m2 alone (n = 6). Drug and metabolite levels in plasma and urine were assessed by high-performance liquid chromatography and parameters of drug exposure were related to hematological toxicity by a sigmoid-maximum effect (Emax) model. RESULTS: Paclitaxel administration significantly increased the epirubicinol area under the concentration-time curve, from 357+/-146 (epirubicin) to 603+/-107 (EP) and 640+/-81 h x ng/ml (GEP), and reduced the renal clearance of epirubicin and epirubicinol by 38 and 52.2% and 34.5 and 53% in GEP- and EP-treated patients, respectively, compared with epirubicin alone. Gemcitabine had no apparent effect on paclitaxel and epirubicin pharmacokinetics, and renal clearance of epirubicin and epirubicinol. The only pharmacokinetic/pharmacodynamic relationship observed was between neutropenia and the time spent above the threshold plasma level of 0.1 micromol/l (tC0.1) of paclitaxel, with the time required to obtain a 50% decrease in neutrophil count (Et50) of GEP being 7.8 h, similar to that of EP. CONCLUSIONS: Paclitaxel and/or its vehicle, Cremophor EL, interferes with the disposition and renal excretion of epirubicin and epirubicinol; gemcitabine has no affect on epirubicin and paclitaxel plasma pharmacokinetics and renal excretion of epirubicin, while neutropenia is not enhanced by gemcitabine.

An improved HPLC method for therapeutic drug monitoring of daunorubicin, idarubicin, doxorubicin, epirubicin, and their 13-dihydro metabolites in human plasma.

A single high-performance liquid chromatography (HPLC) method, suitable for the analysis of daunorubicin, idarubicin, doxorubicin, epirubicin, and their 13-dihydro metabolites is validated in the present study. Preparation of plasma samples was performed by a first extraction of analytes with a chloroform/1-heptanol mixture (9:1) and reextraction with ortophosphoric acid 0.1 M. The chromatographic analysis was carried out by reversed-phase isocratic elution of anthracyclines with a Supelcosil LC-CN 5 mm column (25 cm x 4.6 mm internal diameter; Supelco) and detection was accomplished by spectrofluorimetry at excitation and emission wavelengths of 480 and 560 nm, respectively. All anthracyclines eluted within 15 minutes of injection and the method appeared to be specific, because the chromatographic assay did not show interferences at the retention time of analytes. The linearity, evaluated over a concentration range of 0.4-10,000 ng/mL, gave regression coefficients better than 0.999, with recoveries of doxorubicin-doxorubicinol and epirubicin-epirubicinol of 67%-109% and 61%-109% respectively, and 93%-109% for the other compounds. The limits of detection and quantification were 0.4 ng/mL in a 50-mL sample (40 pg/injection) for all anthracyclines tested. The method proved to be precise and accurate, as the within-day and between-day coefficients of variation were less than 10% and the accuracy of the assay was in the range of 91%-107%. Overall results indicate that it is feasible to analyze all the anthracyclines used in clinical practice and their major metabolites with a single optimized method, thereby simplifying their monitoring in chemotherapeutic regimens of cancer patients.

Drug distribution and pharmacokinetic/pharmacodynamic relationship of paclitaxel and gemcitabine in patients with non-small-cell lung cancer.

BACKGROUND: Gemcitabine and paclitaxel are two of the most active agents in non-small-cell lung cancer (NSCLC), and pharmacologic investigation of the combination regimens including these drugs may offer a valuable opportunity in treatment optimization. The present study investigates the pharmacokinetics and pharmacodynamics of paclitaxel and gemcitabine in chemotherapy-naive patients with advanced NSCLC within a phase I study. PATIENTS AND METHODS: Patients were given i.v. paclitaxel 100 mg/m2 by one-hour infusion followed by gemcitabine 1,500, 1,750 and 2,000 mg/m2 by 30-min administration. Plasma levels of paclitaxel, gemcitabine and its metabolite 2',2'-difluorodeoxyuridine (dFdU) were determined by high-performance liquid chromatography (HPLC). Concentration-time curves were modeled by compartmental and non-compartmental methods and pharmacokinetic/pharmacodynamic (PK/PD) relationships were fitted according to a sigmoid maximum effect (Emax) model. RESULTS: Paclitaxel pharmacokinetics did not change as a result of dosage escalation of gemcitabine from 1,500 to 2,000 mg/m2. A nonproportional increase in gemcitabine peak plasma levels (Cmax, from 18.56 +/- 4.94 to 40.85 +/- 14.85 microg/ml) and area under the plasma concentration-time curve (AUC, from 9.99 +/- 2.75 to 25.01 +/- 9.87 h x microg/ml) at 1,500 and 2,000 mg/m, respectively, was observed, suggesting the occurrence of saturation kinetics at higher doses. A significant relationship between neutropenia and time of paclitaxel plasma levels > or = 0.05 micromol/l was observed, with a predicted time of 10.4 h to decrease cell count by 50%. A correlation was also observed between percentage reduction of platelet count and gemcitabine Cmax, with a predicted effective concentration to induce a 50% decrease of 14.3 microg/ml. CONCLUSION: This study demonstrates the lack of interaction between drugs, the nonproportional pharmacokinetics of gemcitabine at higher doses and the Emax relationship of paclitaxel and gemcitabine with neutrophil and platelet counts, respectively. In addition, gemcitabine 1,500 mg/m2 is the recommended dosage in combination with paclitaxel 100 mg/m2 for future phase II studies, due to its predictable kinetic behaviour and less severe thrombocytopenia than expected.

Manumycin inhibits ras signal transduction pathway and induces apoptosis in COLO320-DM human colon tumour cells.

The aim of the present study was to assess the cytotoxicity of manumycin, a specific inhibitor of farnesyl:protein transferase, as well as its effects on protein isoprenylation and kinase-dependent signal transduction in COLO320-DM human colon adenocarcinoma which harbours a wild-type K-ras gene. Immunoblot analysis of isolated cell membranes and total cellular lysates of COLO320-DM cells demonstrated that manumycin dose-dependently reduced p21 ras farnesylation with a 50% inhibitory concentration (IC50) of 2.51 +/- 0.11 microM and 2.68 +/- 0.20 microM, respectively, while the geranylgeranylation of p21 rhoA and p21rap1 was not affected. Manumycin dose-dependently inhibited (IC50 = 2.40 +/- 0.67 microM) the phosphorylation of the mitogen-activated protein kinase/extracellular-regulated kinase 2 (p42MAPK/ERK2), the main cytoplasmic effector of p21ras, as well as COLO320-DM cell growth (IC50 = 3.58 +/- 0.27 microM) without affecting the biosynthesis of cholesterol. Mevalonic acid (MVA, 100 microM), a substrate of the isoprenoid synthesis, was unable to protect COLO320-DM cells from manumycin cytotoxicity. Finally, manumycin 1-25 microM for 24-72 h induced oligonucleosomal fragmentation in a dose- and time-dependent manner and MVA did not protect COLO320-DM cells from undergoing DNA cleavage. The present findings indicate that the inhibition of p21ras processing and signal transduction by manumycin is associated with marked inhibition of cell proliferation and apoptosis in colon cancer cells and the effect on cell growth does not require the presence of a mutated ras gene for maximal expression of chemotherapeutic activity.