Etoposide pharmacokinetics and survival in patients with small cell lung cancer: A multicentre study

Dual inhibition of topoisomerase II and microtubule of podophyllotoxin derivative 5p overcomes cancer multidrug resistance

Compound 5p is a 4β-N-substituted podophyllotoxin derivative, which exhibited potent activity toward drug-resistant K562/A02 cells and decreased MDR-1 mRNA expression. Here, we further investigated its detail mechanism and tested its antitumor activity. 5p exerted catalytic inhibition of topoisomerase IIα, and didn't show the inhibitor of topoisomerase I. 5p exhibited the inhibitory effect on microtubule polymerization. 5p showed potent anti-proliferation against breast cancer, oral squamous carcinoma, and their drug-resistant cell lines, with resistance index of 0.61 and 0.86, respectively. 5p downregulated the expression levels of P-gp in KBV200 cells and BCRP in MCF7/ADR cells in dose-dependent manner. Moreover, 5p induced KB and KBV200 cells arrest at G2/M phase by up-regulating the expression of γ-H2AX, p-Histone H3 and cyclin B1. 5p induced apoptosis and pyroptosis by increased the expression levels of cleaved-PARP, cleaved-caspase3, N-GSDME as well as LDH release in KB and KBV200 cells. In addition, 5p efficiently impaired tumor growth in KB and KBV200 xenograft mice. Conclusively, this work elucidated the dual inhibitor of topoisomerase II and microtubule of 5p and its mechanism of overcoming the multidrug resistance, indicating that 5p exerts the antitumor potentiality.

Association of lactate dehydrogenase with mortality in incident hemodialysis patients

BACKGROUND

Lactate dehydrogenase (LDH) plays a role in the glucose metabolism of the human body. Higher LDH levels have been linked to mortality in various cancer types; however, the relationship between LDH and survival in incident hemodialysis (HD) patients has not yet been examined. We hypothesized that higher LDH level is associated with higher death risk in these patients.

METHODS

We examined the association of baseline and time-varying serum LDH with all-cause, cardiovascular and infection-related mortality among 109 632 adult incident HD patients receiving care from a large dialysis organization in the USA during January 2007 to December 2011. Baseline and time-varying survival models were adjusted for demographic variables and available clinical and laboratory surrogates of malnutrition-inflammation complex syndrome.

RESULTS

There was a linear association between baseline serum LDH levels and all-cause, cardiovascular and infection-related mortality in both baseline and time-varying models, except for time-varying infection-related mortality. Adjustment for markers of inflammation and malnutrition attenuated the association in all models. In fully adjusted models, baseline LDH levels ≥360 U/L were associated with the highest risk of all-cause mortality (hazard ratios = 1.19, 95% confidence interval 1.14-1.25). In time-varying models, LDH >280 U/L was associated with higher death risk in all three hierarchical models for all-cause and cardiovascular mortality.

CONCLUSIONS

Higher LDH level >280 U/L was incrementally associated with higher all-cause and cardiovascular mortality in incident dialysis patients, whereas LDH <240 U/L was associated with better survival. These findings suggest that the assessment of metabolic functions and monitoring for comorbidities may confer survival benefit to dialysis patients.

Thioredoxin-1 as a biological predictive marker for selecting diffuse large B-cell lymphoma patients for etoposide-containing treatment

OBJECTIVE

In diffuse large B-cell lymphoma (DLBCL), there is an unmet medical need to select patients who would benefit from intensified frontline treatments such as adding etoposide to an R-CHOP regimen.

METHODS

The present work included a retrospective clinical analysis of two patient cohorts and an in vitro study. Primary biopsy samples from DLBCL patients treated with an etoposide-containing high-dose regimen (n = 37) and etoposide-containing frontline treatment (n = 69, R-CHOEP) were studied using immunohistochemical thioredoxin-1 (Trx1) staining. Two DLBCL cell lines expressing Trx1 were cultured, and their expression was silenced using the small interfering RNA knockdown technique. Chemoresistance was tested with doxorubicin, etoposide, vincristine, prednisolone and carboplatin.

RESULTS

Thioredoxin-1 knockdown sensitised DLBCL cells to doxorubicin (P < .0001) but decreased etoposide-induced cell death (P < .00001). In DLBCL patients who received etoposide-containing frontline treatment, low cytoplasmic Trx1 expression was associated with inferior 5-year overall survival (46% vs 76%, P = .026) and disease-specific survival (68% vs 90%, P = .026).

CONCLUSIONS

Strong Trx1 expression appears to increase drug resistance to doxorubicin but sensitises cells to etoposide. This implies that Trx1 expression might be the first predictive biological marker to select the patients who might benefit from adding etoposide to R-CHOP immunochemotherapy.

Polyester-Based Dendrimer Nanoparticles Combined with Etoposide Have an Improved Cytotoxic and Pro-Oxidant Effect on Human Neuroblastoma Cells

Etoposide (ETO) is a cytotoxic drug that exerts its effect by increasing reactive oxygen species (ROS) production. Although ETO is widely used, fast metabolism, poor solubility, systemic toxicity, and multi-drug resistance induction all limit its administration dosage and its therapeutic efficiency. In order to address these issues, a biodegradable dendrimer was prepared for entrapping and protecting ETO and for enhancing its solubility and effectiveness. The achieved dendrimer complex with ETO (CPX 5) showed the typical properties of a well-functioning delivery system, i.e., nanospherical morphology (70 nm), optimal Z-potential (-45 mV), good drug loading (37%), very satisfying entrapment efficiency (53%), and a remarkably improved solubility in biocompatible solvents. In regards to its cytotoxic activity, CPX 5 was tested on neuroblastoma (NB) cells with very promising results. In fact, the dendrimer scaffold and ETO are able to exert per se a cytotoxic and pro-oxidant activity on human NB cells. When CPX 5 is combined with ETO, it shows a synergistic action, slowly releasing the drug over time and significantly improving and protracting bioactivity. On the basis of these findings, the prepared ETO reservoir represents a novel biodegradable and promising device for the delivery of ETO into NB cells.

Serum lactate dehydrogenase predicts survival in small-cell lung cancer patients with brain metastases that were treated with whole-brain radiotherapy

This study aimed to identify factors that predict prognosis after radiotherapy for brain metastases (BMs) from small-cell lung cancer (SCLC). This study retrospectively evaluated 48 consecutive patients who underwent whole-brain radiotherapy (WBRT) for BMs from SCLC between February 2008 and December 2017. WBRT was delivered at a median dose of 30 Gy (range: 30-40 Gy) in 10 fractions (range: 10-16 fractions). Clinical factors were tested for associations with overall survival after WBRT. The median survival and 1-year overall survival rate after WBRT treatment were 232 days and 34.4%, respectively. Univariate analyses revealed that longer survival was associated with Eastern Cooperative Oncology Group performance status of 0-1, asymptomatic BMs, lactate dehydrogenase (LDH) in the normal range, Radiation Therapy Oncology Group-recursive partitioning analysis class 2, and a graded prognostic assessment score of ≥1.5 (P < 0.01, P < 0.01, P < 0.01, P < 0.01 and P < 0.05, respectively). In the multivariate analyses, longer survival was independently associated with asymptomatic BMs [hazard ratio for death (HR), 0.32; 95% confidence interval (CI), 0.12-0.79; P < 0.05] and LDH in the normal range (HR, 0.42; 95% CI, 0.21-0.83; P < 0.05). The presence of symptoms due to BMs and LDH values independently predicted prognosis after WBRT for BMs from SCLC. Elevated LDH may provide valuable information for identifying patients with BMs who could have poor survival outcomes.

Pharmacokinetic interaction between mitotane and etoposide in adrenal carcinoma: a pilot study

Background The combination of mitotane and platinum-etoposide chemotherapy is a front-line treatment in metastatic adrenocortical carcinoma (ACC), although this regimen shows limited efficacy. Pharmacokinetic drug-drug interaction between mitotane, a strong CYP3A4 inducer, and etoposide, which is a substrate of CYP3A4, may contribute to chemoresistance. The aim of this pilot study was to assess the pharmacokinetic interaction between mitotane and etoposide in ACC patients. Methods Five consecutive ACC patients treated with platinum etoposide (120-150 mg/m2 day 1-2-3 at cycle 1), with or without concomitant mitotane, were included. In the absence of limiting toxicity, a dose escalation of etoposide was proposed since cycle 2. Plasma etoposide concentrations were measured using liquid chromatography at 0, 4 and 24 h after each infusion. Clearance and area under the curve (AUC) of etoposide were determined at each cycle. Results Patients received two to six chemotherapy cycles, in association with mitotane (N = 4) or after mitotane discontinuation (N = 1). Etoposide clearance was two-fold higher with concomitant mitotane (4.95 L/h) than after mitotane discontinuation (2.53 L/h, P = 0.014), and 2.5-fold higher than that in reference population not treated with mitotane (1.81 L/h). Etoposide dose escalation was performed in four patients under mitotane, resulting in two minor tumor responses and one severe toxicity (febrile aplasia) at dose of 300 mg/m2/day. Tumor response was associated with higher etoposide AUC (267.3 vs 188.8 mg.h/L, P = 0.04). Conclusion A drug-drug interaction between mitotane and etoposide may contribute to the low efficacy of platinum-etoposide chemotherapy. This pilot study suggests further a potential benefit of increasing etoposide dose in ACC patients receiving mitotane.

Recombinant human erythropoietin prevents etoposide- and methotrexate-induced toxicity in kidney and liver tissues via the regulation of oxidative damage and genotoxicity in Wistar rats

Etoposide (ETO) and methotrexate (MTX) are two effective chemotherapeutic drugs. However, the clinical use of these drugs is limited by its toxicity in normal tissues, especially in kidney and in liver tissues. Recombinant human erythropoietin (rhEPO), erythropoietin hormone, has also been shown to exert tissue protective effects. The purpose of this study was to explore the protective effect of rhEPO against oxidative stress and genotoxicity induced by ETO and MTX in vivo. Adult male Wistar rats were divided into 10 groups (6 animals each): control group, rhEPO alone group, ETO alone group, MTX alone group and rhEPO + ETO/MTX groups. In rhEPO + ETO/MTX groups, three doses of pretreatment with rhEPO were performed: 1000, 3000 and 6000 IU/kg. Our results showed that rhEPO pretreatment protects liver and kidney tissues against oxidative stress induced by the anticancer drugs. The glycoprotein decreased malondialdehyde (MDA) levels, reduced catalase activity and ameliorated glutathione depletion. Furthermore, we showed that rhEPO administration prevented drug-induced DNA damage accessed by comet test. Altogether, our results suggested a protective role of rhEPO, especially at 3000 IU/kg, against ETO- and MTX-induced oxidative stress and genotoxicity in vivo.

Pharmacokinetics and dose adjustment of etoposide administered in a medium-dose etoposide, cyclophosphamide and total body irradiation regimen before allogeneic hematopoietic stem cell transplantation

BACKGROUND

We investigated the pharmacokinetics of etoposide (ETP) to reduce the inter-individual variations of ETP concentrations in patients with acute leukemia who underwent allogeneic hematopoietic stem cell transplantation. We also carried out an in vivo study using rats to verify the dose adjustment.

METHODS

This study included 20 adult patients. ETP was administered intravenously at a dose of 15 mg/kg once daily for 2 days (total dose: 30 mg/kg) combined with standard conditioning of cyclophosphamide and total body irradiation. In an in vivo study using rats, ETP was administered intravenously at a dose of 15 mg/kg or an adjusted dose. The ETP plasma concentration was determined by using HPLC. The pharmacokinetic parameters were estimated by using a 1-compartment model.

RESULTS

The peak concentration (Cmax) of ETP and the area under the plasma concentration-time curve (AUC) of ETP differed greatly among patients (range of Cmax, 51.8 - 116.5 μg/mL; range of AUC, 870 - 2015 μg · h/mL). A significant relationship was found between Cmax and AUC (R = 0.85, P < 0.05). Distribution volume (Vd) was suggested to be one of the factors of inter-individual variation in plasma concentration of ETP in patients (range of Vd, 0.13 - 0.27 L/kg), and correlated with Alb and body weight (R = 0.56, P < 0.05; R = 0.40, P < 0.05 respectively). We predicted Vd of rats by body weight of rats (with normal albumin levels and renal function), and the dose of ETP was adjusted using predicted Vd. In the dose adjustment group, the target plasma ETP concentration was achieved and the variation of plasma ETP concentration was decreased.

CONCLUSION

The results suggested that inter-individual variation of plasma concentration of ETP could be reduced by predicting Vd. Prediction of Vd is effective for reducing individual variation of ETP concentration and might enable a good therapeutic effect to be achieved.

Pleural LDH as a prognostic marker in adenocarcinoma lung with malignant pleural effusion

To study the performance of serum and pleural lactate dehydrogenase (LDH) level in predicting survival in patients with adenocarcinoma lung presenting with malignant pleural effusions (MPE) at initial diagnosis.Retrospective cohort study of the patient hospitalized for adenocarcinoma lung with MPE in year 2012.Univariate analyses showed lower pleural fluid LDH 667 (313-967) versus 971 (214-3800), P = 0.04, female gender 9 (100%) versus 27 (41.5%), P = 0.009, never smoking status 9 (100%) versus 36 (55.3%), P = 0.009, and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy 8 (89%) versus 26 (40%), P = 0.009 to correlate with survival of more than 1.7 year versus less than 1.7 year. In multivariate analysis, low pleural fluid LDH and female gender maintained significance. The pleural LDH level of ≤1500 and >1500 U/L discriminated significantly (P = 0.009) between survival.High pleural LDH (>1500 IU/L) predicts shorter survival (less than a year) in patients with adenocarcinoma lung presenting with MPE at the time of initial diagnosis. This marker may be clinically applied for selecting therapeutic modality directed at prevention of reaccumulation of MPE. Patients with low pleural LDH may be considered suitable for measures that provide more sustained effect on prevention of reaccumulation such as chemical pleurodesis or tunneled pleural catheter.

Transdermal Delivery of Etoposide Phosphate I: In Vitro and In Vivo Evaluation

Cancer chemotherapy frequently requires long periods of multiple intravenous infusions that often results in patients opting out of treatment. The main purpose of this study was to investigate the feasibility of delivering one of these anticancer agents: etoposide phosphate (ETP) transdermally using iontophoresis and a combination of iontophoresis/microporation. The iontophoresis conditions for ETP were first optimized in vitro then tested in vivo in a rabbit model. Both ETP and its active form etoposide (VP) were quantified in dermis (via microdialysis sampling) and in plasma, with a specially developed high-performance liquid chromatography method. In vitro, the amount of total etoposide permeated and the steady state flux increased (p < 0.05) with increase in iontophoretic current densities (100-400 μA/cm(2)). At 300 μA/cm(2), microporation/iontophoresis further improved both parameters by 2- and 2.8-fold, respectively. In vivo, exposure increased proportionally to current density in plasma, whereas dermal concentration dropped significantly at the highest current density. Microporation led to a 50% increase in Cmax and AUClast values in both skin and plasma. In conclusion, a mild current density (300 μA/cm(2)) and a small surface area (10.1 cm(2)) achieved and maintained the minimum effective concentration for the entire duration of electrical current delivery; microporation further increased the plasma concentrations at the same current density.

Identifying Malignant Pleural Effusion by A Cancer Ratio (Serum LDH: Pleural Fluid ADA Ratio)

Aim

We studied the diagnostic potential of serum lactate dehydrogenase (LDH) in malignant pleural effusion.

Methods

Retrospective analysis of patients hospitalized with exudative pleural effusion in 2013.

Results

Serum LDH and serum LDH: pleural fluid ADA ratio was significantly higher in cancer patients presenting with exudative pleural effusion. In multivariate logistic regression analysis, pleural fluid ADA was negatively correlated 0.62 (0.45–0.85, p = 0.003) with malignancy, whereas serum LDH 1.02 (1.0–1.03, p = 0.004) and serum LDH: pleural fluid ADA ratio 0.94 (0.99–1.0, p = 0.04) was correlated positively with malignant pleural effusion. For serum LDH: pleural fluid ADA ratio, a cut-off level of >20 showed sensitivity, specificity of 0.98 (95 % CI 0.92–0.99) and 0.94 (95 % CI 0.83–0.98), respectively. The positive likelihood ratio was 32.6 (95 % CI 10.7–99.6), while the negative likelihood ratio at this cut-off was 0.03 (95 % CI 0.01–0.15).

Conclusion

Higher serum LDH and serum LDH: pleural fluid ADA ratio in patients presenting with exudative pleural effusion can distinguish between malignant and non-malignant effusion on the first day of hospitalization. The cut-off level for serum LDH: pleural fluid ADA ratio of >20 is highly predictive of malignancy in patients with exudative pleural effusion (whether lymphocytic or neutrophilic) with high sensitivity and specificity.

Serum lactate dehydrogenase and survival following cancer diagnosis

BACKGROUND

There is evidence that high level of serum lactate dehydrogenase (LDH) is associated with poorer overall survival in several malignancies, but its link to cancer-specific survival is unclear.

METHODS

A total of 7895 individuals diagnosed with cancer between 1986 and 1999 were selected for this study. Multivariable Cox proportional hazards regression was used to assess overall and cancer-specific death by the z-score and clinical categories of serum LDH prospectively collected within 3 years before diagnosis. Site-specific analysis was performed for major cancers. Analysis was repeated by different lag times between LDH measurements and diagnosis.

RESULTS

At the end of follow-up, 5799 participants were deceased. Hazard ratios (HRs) and 95% confidence intervals (CIs) for overall and cancer-specific death in the multivariable model were 1.43 (1.31-1.56) and 1.46 (1.32-1.61), respectively, for high compared with low prediagnostic LDH. Site-specific analysis showed high LDH to correlate with an increased risk of death from prostate, pulmonary, colorectal, gastro-oesophageal, gynaecological and haematological cancers. Serum LDH assessed within intervals closer to diagnosis was more strongly associated with overall and cancer-specific death.

CONCLUSIONS

Our findings demonstrated an inverse association of baseline serum LDH with cancer-specific survival, corroborating its role in cancer progression.

Inorganic nanolayers: structure, preparation, and biomedical applications

Hydrotalcite-like compounds are two-dimensional inorganic nanolayers also known as clay minerals or anionic clays or layered double hydroxides/layered hydroxy salts, and have emerged as a single type of material with numerous biomedical applications, such as drug delivery, gene delivery, cosmetics, and biosensing. Inorganic nanolayers are promising materials due to their fascinating properties, such as ease of preparation, ability to intercalate different type of anions (inorganic, organic, biomolecules, and even genes), high thermal stability, delivery of intercalated anions in a sustained manner, high biocompatibility, and easy biodegradation. Inorganic nanolayers have been the focus for researchers over the last decade, resulting in widening application horizons, especially in the field of biomedical science. These nanolayers have been widely applied in drug and gene delivery. They have also been applied in biosensing technology, and most recently in bioimaging science. The suitability of inorganic nanolayers for application in drug delivery, gene delivery, biosensing technology, and bioimaging science makes them ideal materials to be applied for theranostic purposes. In this paper, we review the structure, methods of preparation, and latest advances made by inorganic nanolayers in such biomedical applications as drug delivery, gene delivery, biosensing, and bioimaging.

Which polymer is more suitable for etoposide: A comparison between two kinds of drug loaded polymeric micelles in vitro and in vivo?

In this paper, we systemly compared the two kinds of VP16 (etoposide) loaded polymers micelles, monomethyl poly (ethylene glycol)-poly (lactic acid) (MPEG-PDLLA) and monomethyl poly (ethylene glycol)-poly (ϵ-caprolactone) (MPEG-PCL) in vitro and in vivo. Molecular modeling study was used as a novel means to compare the two formulations. In vitro, the micelle samples were fully characterized by TEM, XRD, drug loading (DL), Encapsulation efficiency (EE), stability and MTT. The stability study revealed that MPEG-PDLLA-VP16 had the significant advantage of 100% drug retention within 48 h compared to MPEG-PCL-VP16 with 40%, conform to the computer simulation model results. Cellular uptake figured that MPEG-PDLLA-VP16 had a 7 times larger uptake rate in the H460 cell line. In vivo, pharmacodynamics results showed MPEG-PDLLA-VP16 perform no significant difference with VP16 clinical formulations (10, 20mg/kg). However, MPEG-PCL-VP16 had no difference between different dosages on anticancer activities. Plasma pharmacokinetics results showed that the two micelle formulations prolong the half-life of VP16 twice than that of VP16 clinical formulations. In conclusion, micelle were better choice for cancer treatment on reducing drug toxic. In this study, the results also indicated that MPEG-PDLLA was more suitable for VP16 than MPEG-PCL as a more promising formulation for clinical cancer treatment.

A population pharmacodynamic model for lactate dehydrogenase and neuron specific enolase to predict tumor progression in small cell lung cancer patients

The development of individualized therapies poses a major challenge in oncology. Significant hurdles to overcome include better disease monitoring and early prediction of clinical outcome. Current clinical practice consists of using Response Evaluation Criteria in Solid Tumors (RECIST) to categorize response to treatment. However, the utility of RECIST is restricted due to limitations on the frequency of measurement and its categorical rather than continuous nature. We propose a population modeling framework that relates circulating biomarkers in plasma, easily obtained from patients, to tumor progression levels assessed by imaging scans (i.e., RECIST categories). We successfully applied this framework to data regarding lactate dehydrogenase (LDH) and neuron specific enolase (NSE) concentrations in patients diagnosed with small cell lung cancer (SCLC). LDH and NSE have been proposed as independent prognostic factors for SCLC. However, their prognostic and predictive value has not been demonstrated in the context of standard clinical practice. Our model incorporates an underlying latent variable ("disease level") representing (unobserved) tumor size dynamics, which is assumed to drive biomarker production and to be influenced by exposure to treatment; these assumptions are in agreement with the known physiology of SCLC and these biomarkers. Our model predictions of unobserved disease level are strongly correlated with disease progression measured by RECIST criteria. In conclusion, the proposed framework enables prediction of treatment outcome based on circulating biomarkers and therefore can be a powerful tool to help clinicians monitor disease in SCLC.

A phase I study of AT-101 with cisplatin and etoposide in patients with advanced solid tumors with an expanded cohort in extensive-stage small cell lung cancer

BACKGROUND

A phase I, dose-escalation study of AT-101 with cisplatin and etoposide was conducted to determine the maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D), safety and pharmacokinetics in patients with advanced solid tumors, with an expanded cohort in patients with extensive-stage small cell lung cancer (ES-SCLC) to assess preliminary activity.

METHODS

In the dose escalation portion, increasing doses of AT-101 were administered orally BID on days 1-3 along with cisplatin on day 1 and etoposide on days 1-3 of a 21 day cycle. At the RP2D, an additional 7 patients with untreated ES-SCLC were enrolled.

RESULTS

Twenty patients were enrolled in the dose-escalation cohort, and 7 patients with ES-SCLC were enrolled in the expanded cohort. The MTD/RP2D was established at AT-101 40 mg BID days 1-3 with cisplatin 60 mg/m2 and etoposide 120 mg/m2 on day 1 of a 21 day cycle with pegfilgrastim support. Two DLTs of neutropenic fever were seen at dose level 1. After the addition of pegfilgrastim, no additional DLTs were observed. Grade 3/4 treatment-related toxicities included: diarrhea, increased AST, neutropenia, hypophosphatemia, hyponatremia, myocardial infarction and pulmonary embolism. No apparent PK interactions were observed between the agents. Preliminary activity was observed with PRs in patients with ES-SCLC, high-grade neuroendocrine tumor, esophageal cancer and NSCLC.

CONCLUSIONS

AT-101 with cisplatin and etoposide is well tolerated with growth factor support. Anti-tumor activity was observed in a variety of cancers including ES-SCLC, supporting further investigation with BH-3 mimetics in combination with standard chemotherapy for ES-SCLC.

Development and in vitro evaluation of a novel lipid nanocapsule formulation of etoposide

Small cell lung cancer (SCLC) is the most aggressive carcinoma in thoracic oncology, unfortunately, despite chemotherapy, relapse is constant. The effect of etoposide, a major drug used against SCLC, can potentially be enhanced after its encapsulation in nanocarriers. The aim of this study was to use the technology of lipid nanocapsules (LNCs) to obtain nanocarriers with drug loadings compatible with clinical use and with an industrial process. Solubility studies with different co-solvent were first performed, then several process were developed to obtain LNCs. LNCs were then characterized (size, zeta potential, and drug loading). The best formulation called Ω-LNCs had a size of 54.1±2.0 nm and a zeta potential of -5.8±3.5 mV and a etoposide drug loading of 5.7±0.3mg/g. The characteristics of this formulation were maintained after freeze drying and after a 15× scale-up. Release studies in a media mimicking plasma composition showed that 40% of the drug was released from the LNCs after 48 h. Moreover the activity of etoposide after encapsulation was enhanced on H209 cells, IC50 was 100 μM and 2.5 μM for etoposide and etoposide LNCs respectively. Unfortunately the formulation failed to be more cytotoxic than etoposide alone on H69AR cells that are resistant to etoposide. This study showed that is was possible to obtain a new etoposide nanocarrier without the use of organic solvent, that the process is suitable for scale-up and freeze drying and finally that etoposide activity is maintained which is very promising for future treatment of SCLC.

The in vitro sustained release profile and antitumor effect of etoposide-layered double hydroxide nanohybrids

Magnesium-aluminum layered double hydroxides intercalated with antitumor drug etoposide (VP16) were prepared for the first time using a two-step procedure. The X-ray powder diffraction data suggested the intercalation of VP16 into layers with the increased basal spacing from 0.84–1.18 nm was successful. Then, it was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis, and transmission electron microscopy. The prepared nanoparticles, VP16-LDH, showed an average diameter of 62.5 nm with a zeta potential of 20.5 mV. Evaluation of the buffering effect of VP16-LDH indicated that the nanohybrids were ideal for administration of the drugs that treat human stomach irritation. The loading amount of intercalated VP16 was 21.94% and possessed a profile of sustained release. The mechanism of VP16-LDH release in the phosphate buffered saline solution at pH 7.4 is likely controlled by the diffusion of VP16 anions from inside to the surface of LDH particles. The in vitro cytotoxicity and antitumor assays indicated that VP16-LDH hybrids were less toxic to GES-1 cells while exhibiting better antitumor efficacy on MKN45 and SGC-7901 cells. These results imply that VP16-LDH is a potential antitumor drug for a broad range of gastric cancer therapeutic applications.

Oral treatment with etoposide in small cell lung cancer - dilemmas and solutions

Background

Etoposide is a chemotherapeutic agent, widely used for the treatment of various malignancies, including small cell lung cancer (SCLC), an aggressive disease with poor prognosis. Oral etoposide administration exhibits advantages for the quality of life of the patient as well as economic benefits. However, widespread use of oral etoposide is limited by incomplete and variable bioavailability. Variability in bioavailability was observed both within and between patients. This suggests that some patients may experience suboptimal tumor cytotoxicity, whereas other patients may be at risk for excess toxicity.

Conclusions

The article highlights dilemmas as well as solutions regarding oral treatment with etoposide by presenting and analyzing relevant literature data. Numerous studies have shown that bioavailability of etoposide is influenced by genetic, physiological and environmental factors. Several strategies were explored to improve bioavailability and to reduce pharmacokinetic variability of oral etoposide, including desired and undesired drug interactions (e.g. with ketoconazole), development of suitable drug delivery systems, use of more water-soluble prodrug of etoposide, and influence on gastric emptying. In addition to genotype-based dose administration, etoposide is suitable for pharmacokinetically guided dosing, which enables dose adjustments in individual patient.

Further, it is established that oral and intravenous schedules of etoposide in SCLC patients do not result in significant differences in treatment outcome, while results of toxicity are inconclusive. To conclude, the main message of the article is that better prediction of the pharmacokinetics of oral etoposide may encourage its wider use in routine clinical practice.

Therapeutic drug monitoring in cancer chemotherapy

For a select number of drugs, proper management of patients includes monitoring serum or plasma concentrations of the drugs and adjusting the doses accordingly - this practice is referred to as therapeutic drug monitoring (TDM). The need for TDM arises when pharmacokinetic variability of drugs is not easily accounted for by common clinical parameters. Many chemotherapeutic drugs have large interindividual variability, yet TDM is not commonplace in chemotherapy management. This review will discuss pharmacokinetics in the context of chemotherapeutic drugs, examine the few instances where TDM is currently used in the field of oncology and propose other drugs where TDM might be useful for dose adjustments in the management of chemotherapy.

Drug exposure: still an excellent biomarker

Relationships between plasma drug concentrations and clinical outcome have been defined for various chemotherapeutic agents, showing that drug exposure may be a marker of toxicity, mainly hematological and gastrointestinal toxicity, as well as efficacy, expressed as tumor response and survival. Biomarkers provide information for guidance in dosing and the minimization of interindividual variation in response. Drug exposure is commonly measured with parameters such as area under the plasma concentration-time curve, steady-state plasma or serum concentrations, peak concentrations and duration above a threshold concentration. In this review, we focus on drugs where pharmacokinetic/pharmacodynamic relationships as well as systemic exposure have been associated to toxicity and/or efficacy in solid and hematological tumors, these include: carboplatin, methotrexate, busulphan, 5-fluorouracil, etoposide, anthracyclines, irinotecan, vinorelbine and docetaxel.

Perspectives on tissue interactions in development and disease

From the morphogenetic movements of the three germ layers during development to the reactive stromal microenvironment in cancer, tissue interactions are vital to maintaining healthy organ morphologic architecture and function. The stromal compartment is thought to be complicit in tumor progression and, as such, represents an opportune target for disease therapies. However, recent developments in our understanding of the diversity of the stromal compartment and the lack of appropriate models to study its relevance in human disease have limited our further understanding of the role of tissue interactions in tumor progression. The failure any model to fully recapitulate the complexities of systemic biology continue to create a higher imperative for incorporating various perspectives into a broader understanding for the ultimate goal of designing interventional therapies. Understanding this potential, this review examines the biological models used to study stromal-epithelial interactions and includes an attempt to incorporate behavioral terminology to define and mathematically model ecological relationships in stromal-epithelial interactions. In addition, the current attempt to incorporate these diverse ecological perspectives into in silico mathematical models through cross-disciplinary coordination is reviewed, which will provide a fresh perspective on defining cell group behavior and tissue ecology in disease and hopefully lead to the generation of new hypotheses to be empirically validated.

MRP- and BCL-2-mediated drug resistance in human SCLC: effects of apoptotic sphingolipids in vitro

Multidrug-resistance-associated protein (MRP) and BCL-2 contribute to drug resistance expressed in SCLC. To establish whether MRP-mediated drug resistance affects sphingolipid (SL)-induced apoptosis in SCLC, we first examined the human SCLC cell line, UMCC-1, and its MRP over-expressing, drug-resistant subline, UMCC-1/VP. Despite significantly decreased sensitivity to doxorubicin (Dox) and to the etoposide, VP-16, the drug-selected line was essentially equally as sensitive to treatment with exogenous ceramide (Cer), sphingosine (Sp) or dimethyl-sphingosine (DMSP) as the parental line. Next, we observed that high BCL-2-expressing human H69 SCLC cells, that were approximately 160-fold more sensitive to Dox than their combined BCL-2 and MRP-over-expressing (H69AR) counterparts, were only approximately 5-fold more resistant to DMSP. Time-lapse fluorescence microscopy of either UMCC cell line treated with DMSP-Coumarin revealed comparable extents and kinetics of SL uptake, further ruling out MRP-mediated effects on drug uptake. DMSP potentiated the cytotoxic activity of VP-16 and Taxol, but not Dox, in drug-resistant UMCC-1/VP cells. However, this sensitization did not appear to involve DMSP-mediated effects on the function of MRP in drug export; nor did DMSP strongly shift the balance of pro-apoptotic Sps and anti-apoptotic Sp-1-Ps in these cells. We conclude that SL-induced apoptosis markedly overcomes or bypasses MRP-mediated drug resistance relevant to SCLC and may suggest a novel therapeutic approach to chemotherapy for these tumors.

JWA sensitizes P-glycoprotein-mediated drug-resistant choriocarcinoma cells to etoposide via JNK and mitochondrial-associated signal pathway

A major obstacle in cancer chemotherapy is the phenomenon of multidrug resistance (MDR), increased P-glycoprotein expression, and abnormal apoptotic processes that may contribute to MDR. Our previous studies demonstrated that JWA is a pro-apoptotic molecule and required for arsenic trioxide and all-trans-retinoic acid-induced cancer cell apoptosis. In this study, the role of JWA in mediating MDR during treatment of choriocarcinoma cells was examined. Data showed that JWA expression was reduced significantly by etoposide (VP16) in JAR MDR cells (JAR/VP16) compared to parent JAR cells. VP16-induced apoptosis in JAR cells was dependent upon the presence of JWA. Knockdown of JWA attenuated VP16-induced apoptosis, and was accompanied by significantly reduced caspase-9 activity and inhibition of JNK phosphorylation. Loss of mitochondrial transmembrane potential induced by VP16 was accompanied by higher JWA expression. JWA was also involved in downregulation of P-glycoprotein through JNK signal pathway. These results suggest that JWA may play an important role in the therapeutic responses to chemotherapeutic agents used to treat choriocarcinoma.