Hypofractionated radiotherapy for breast cancer is becoming increasingly important. The scientific background of this development as well as the introduction of the simultaneous integrated boost to the primary tumor region in this context are discussed here.
Breast cancer; Hypofractionation; Radiotherapy
We report on a 72-year-old male patient who developed sarcoidosis of the mediastinal lymph nodes, the liver, and the prostate 11 years ago. Seven years later, he underwent transurethral resection of the prostate by laser due to hematuria. Pathology of the resected chips showed a ‘granulomatous prostatitis with epitheloid cells’. Malignancy was histologically excluded at that time. Four years later, he was diagnosed with an undifferentiated prostate carcinoma, with a Gleason score of 5 + 4 = 9. After initiation of antihormonal therapy, he underwent radical prostatectomy and pelvic lymphadenectomy, which revealed a pT3b pN1 carcinoma with infiltrated resection margins. Three months later, the prostate-specific antigen level was 1.4 ng/ml, and a local recurrence was suspected by ultrasound; consequently, a 68Ga-prostate-specific membrane antigen (PSMA) PET/CT was performed. This examination seemed to confirm the local recurrence, a right pelvic lymph node metastasis, and a hepatic metastasis. However, ultrasound with contrast medium could not confirm the metastatic spread to the liver. In palliative intention, radiotherapy of the pelvis was done. After 50 Gy, the supposed recurrence had markedly shrunk, and an additional boost dose with 16.2 Gy was applied. Two years later, the patient is still free of disease. Due to this clinical development, we doubt the diagnosis of a fulminant progression of the prostate cancer as suspected by PSMA-PET/CT. Instead, we suspect a recurrence of the previously proven sarcoidosis leading to false-positive results. Our focus in this report is on the interaction between PSMA-PET/CT and sarcoidosis. Another report on a case of sarcoidosis of the spleen seems to confirm this possibility [Kobe et al: Clin Nucl Med 2015;40: 897–898].
Prostate cancer; Sarcoidosis; PET/CT; Prostate-specific membrane antigen; Radiotherapy
In the session on “Pharmacodynamic studies to demonstrate efficacy and safety”, presentations were made on methods of evaluating airway deposition of inhaled corticosteroids and bronchodilators, and systemic exposure indirectly using pharmacodynamic study designs. For inhaled corticosteroids, limitations of measuring exhaled nitric oxide and airway responsiveness to adenosine for anti-inflammatory effects were identified, whilst measurement of 18-h area under the cortisol concentration–time curve was recommended for determining equivalent systemic exposure. For bronchodilators, methacholine challenge was recommended as the most sensitive method of determining the relative amount of β-agonist or anti-muscarinic agent delivered to the airways. Whilst some agencies, such as the Food and Drug Administration (FDA), do not require measuring systemic effects when pharmacokinetic measurements are feasible, the European Medicines Agency requires measurement of heart rate and serum potassium, and some require serial electrocardiograms when bioequivalence is not established by pharmacokinetic (PK) studies. The Panel Discussion focused on whether PK would be the most sensitive marker of bioequivalence. Furthermore, there was much discussion about the FDA draft guidance for generic fluticasone propionate/salmeterol. The opinion was expressed that the study design is not capable of detecting a non-equivalent product and would require an unfeasibly large sample size.
inhaled bronchodilators; inhaled corticosteroids; methacholine; pharmacodynamics
Garment-like giant congenital melanocytic nevi are very rare, and those being treated are most often offered excision and split-thickness skin transplantation. Due to the risk of restricted mobility secondary to shrinkage and hypertrophic scarring of the transplant, we treated to date the largest reported giant congenital melanocytic nevus (16% total body surface area) with Integra dermal regeneration template (Integra Life Sciences, Plainsboro, N.J.), giving a more functional skin reconstruction. In addition, the dermal regeneration template had to be covered with split-thickness skin transplant including multiple smaller nevi due to lack of larger area with normal skin.
The authors prospectively evaluated the performance of a proprietary molecular testing platform using one-step nucleic acid amplification (OSNA) for the detection of metastatic carcinoma in sentinel lymph nodes (SLNs) in a large multicenter trial and compared the OSNA results with the results from a detailed postoperative histopathologic evaluation (reference pathology) and from intraoperative imprint cytology (IC).
In total, 1044 SLN samples from 496 patients at 11 clinical sites were analyzed. Alternate 1-mm sections were subjected to either detailed histopathologic evaluation with hematoxylin and eosin and pancytokeratin immunostaining or the OSNA Breast Cancer System, which was calibrated to detect tumor deposits >0.2 mm by measuring cytokeratin 19 messenger RNA. At 7 sites, IC was performed before permanent section. The OSNA results were classified as negative (<250 copies/μL), micrometastases (from ≥250 to <5000 copies/μL), or macrometastases (≥5000 copies/μL).
The sensitivity and specificity of the OSNA breast cancer system compared with reference pathology were 77.5% (95% confidence interval, 69.7%-84.2%) and 95.8% (95% confidence interval, 94.3%-97.0%), respectively, before discordant case analyses (DCA). Sensitivity and specificity after DCA were 82.7% and 97.7%, and final concordance was 95.8%. Performance for invasive lobular carcinoma demonstrated 88.2% sensitivity (95% confidence interval, 63.6%-98.5%) and 98.5% specificity (95% confidence interval, 92%-100%). The sensitivity of OSNA was significantly better than that of IC (80% vs 63%; P =.0229).
The OSNA breast cancer system proved to be highly accurate for the detection of metastatic breast cancer in axillary SLNs. Sensitivity was comparable to that predicted for conventional postoperative histologic examination at 2-mm intervals and was significantly more sensitive than IC. Automation, semiquantitative results enabling the differentiation of macrometastasis and micrometastasis, and rapid results render the assay suitable for intraoperative and/or permanent evaluation of SLNs.
breast; carcinoma; sentinel; lymph nodes; nucleic acid amplification; OSNA
The present study aimed to examine the enantiomer-selective pharmacokinetics (PK), relative bioavailability (Frel), and sex effects of various oral dosage forms of racemic alpha-lipoic acid (ALA). In an open-label, randomized, four-period, four-sequence crossover study, 24 healthy adult subjects (12 males and 12 females) received single doses of 600 mg of ALA in fasted state at four different occasions as follows: three 200 mg tablets (T 200); two 300 mg tablets (T 300); one 600 mg tablet (T 600); and a racemic ALA solution (OS). All tablet formulations (Thioctacid HR) were considered test treatments, while the OS (Thioctacid, 600 T) served as the reference treatment. Serial blood samples were collected over 8 hours postdose to quantify R-(+)- and S-(−)-ALA enantiomer plasma concentrations for the PK evaluation. The maximum observed plasma concentration (Cmax) and total exposure (area under the curve [AUC]0–t) were compared between treatments by analysis of variance. Weight-normalized Cmax and the AUC data of male and female study subjects were applied to examine the presence of sex effects. All treatments displayed rapid absorption of both enantiomers with median time to maximum concentration (tmax) values ranging from 0.33–0.5 hours. The Frel of all tablet formulations was comparable, with R-(+)-enantiomer Cmax test/reference ratios ranging from 36% (T 600) to 43% (T 200), and R-(+)-enantiomer AUC test/reference ratios ranging from 64% (T 600) to 79% (T 300), indicating a favorable Frel of all tablet formulations, especially in terms of the total extent of absorption (AUC). An examination of weight-normalized female/male Cmax and AUC sex ratios for both ALA enantiomers indicated the absence of a significant sex effect for Cmax, as well as 20%–26% and 25%–32% higher R-(+)- and S-(−)-ALA enantiomer AUC outcomes in females when compared to males. The observed modest sex effect was comparable for both ALA enantiomers and across all formulations, and it did not appear to require a dose adjustment in clinical practice.
alpha-lipoic acid; thioctic acid; enantiomers; sex effect; formulation effect; bioavailability
AP301 is an activator of ENaC-mediated Na+ uptake for the treatment of pulmonary permeability edema in acute respiratory distress syndrome (ARDS). The purpose of this “first-in-man” study was to examine local and systemic safety and systemic exposure of ascending single doses of AP301, when inhaled by healthy male subjects. In a double-blind, placebo-controlled study, 48 healthy male subjects were randomized to 6 ascending dose groups (single doses up to 120 mg) of 8 subjects each (3:1 randomization of AP301: placebo). Serial assessments included spirometry, exhaled nitric oxide (eNO), vital signs, ECG, safety laboratory, adverse events (AE), and blood samples for the quantification of AP301 in plasma. Descriptive statistics was applied. All 48 subjects received treatment, and completed the study as per protocol. No serious, local (e.g., hoarseness, cough, bronchospasm), or dose-limiting AEs were noted. None of the assessments indicated notable dose or time-related alterations of safety outcomes. Observed AP301 systemic exposure levels were very low, with mean Cmax values of <2.5 ng/mL in the highest dose groups. Inhaled AP301 single doses up to 120 mg were safe and well tolerated by healthy male subjects. Distribution of inhaled AP301 was largely confined to the lung, as indicated by very low AP301 systemic exposure levels.
AP301; ENaC activator; first-in-man study; ARDS
Late effects of therapy for Hodgkin's disease include secondary malignancies like leukemia, lymphoma or solid tumors developing after long periods of latency. Ionizing radiation often causes the last group. The highest risks have been described for induced breast and lung cancers. We are the first to report a malignant triton tumor (MTT) as a secondary malignancy after radiotherapy and chemotherapy for Hodgkin's lymphoma. MTT is a very rare subtype of malignant peripheral nerve sheath tumors with rhabdomyoblastic differentiation and an aggressive course of disease.
Triton tumor; Radiotherapy; Second malignancy; Hodgkin's disease
The involvement of nuclear factor kappa B (NF-κB) in several processes in the postnatal and adult brain, ranging from neuronal survival to synaptogenesis and plasticity, has been documented. In contrast, little is known about the functions of NF-κB during embryonic brain development. It is shown here that NF-κB is selectively activated in neocortical neural progenitor cells in the developing mouse telencephalon. Blockade of NF-κB activity leads to premature cortical neuronal differentiation and depletion of the progenitor cell pool. Conversely, NF-κB activation causes decreased cortical neurogenesis and expansion of the progenitor cell compartment. These effects are antagonized by the proneuronal transcription factor Hes6, which physically and functionally interacts with RelA-containing NF-κB complexes in cortical progenitor cells. In turn, NF-κB exerts an inhibitory effect on the ability of Hes6 to promote cortical neuronal differentiation. These results reveal previously uncharacterized functions and modes of regulation for NF-κB and Hes6 during cortical neurogenesis.
PointBreak (A Study of Pemetrexed, Carboplatin and Bevacizumab in Patients With Nonsquamous Non-Small Cell Lung Cancer) compared the efficacy and safety of pemetrexed (Pem) plus carboplatin (C) plus bevacizumab (Bev) followed by pemetrexed plus bevacizumab (PemCBev) with paclitaxel (Pac) plus carboplatin (C) plus bevacizumab (Bev) followed by bevacizumab (PacCBev) in patients with advanced nonsquamous non–small-cell lung cancer (NSCLC).
Patients and Methods
Patients with previously untreated stage IIIB or IV nonsquamous NSCLC and Eastern Cooperative Oncology Group performance status of 0 to 1 were randomly assigned to receive pemetrexed 500 mg/m2 or paclitaxel 200 mg/m2 combined with carboplatin area under the curve 6 and bevacizumab 15 mg/kg every 3 weeks for up to four cycles. Eligible patients received maintenance until disease progression: pemetrexed plus bevacizumab (for the PemCBev group) or bevacizumab (for the PacCBev group). The primary end point of this superiority study was overall survival (OS).
Patients were randomly assigned to PemCBev (n = 472) or PacCBev (n = 467). For PemCBev versus PacCBev, OS hazard ratio (HR) was 1.00 (median OS, 12.6 v 13.4 months; P = .949); progression-free survival (PFS) HR was 0.83 (median PFS, 6.0 v 5.6 months; P = .012); overall response rate was 34.1% versus 33.0%; and disease control rate was 65.9% versus 69.8%. Significantly more study drug–related grade 3 or 4 anemia (14.5% v 2.7%), thrombocytopenia (23.3% v 5.6%), and fatigue (10.9% v 5.0%) occurred with PemCBev; significantly more grade 3 or 4 neutropenia (40.6% v 25.8%), febrile neutropenia (4.1% v 1.4%), sensory neuropathy (4.1% v 0%), and alopecia (grade 1 or 2; 36.8% v 6.6%) occurred with PacCBev.
OS did not improve with the PemCBev regimen compared with the PacCBev regimen, although PFS was significantly improved with PemCBev. Toxicity profiles differed; both regimens demonstrated tolerability.
To determine azelastine hydrochloride (AZE) and fluticasone propionate (FP) bioavailabilities of the novel nasal spray combination product MP 29-02, compared with MP29-02-based products containing only AZE (MP29-02-AZE-mono), FP (MP29-02-FP-mono), marketed AZE and FP single entity products (Astelin® and FP Boehringer-Ingelheim; FP-BI).
Two randomized, three period, six sequence, three treatment crossover studies were conducted in healthy subjects. Study 1 administered 200 µg FP as MP29-02, MP29-02-FP-mono or FP-BI. Study 2 administered 548 µg AZE as MP29-02, MP29-02-AZE-mono or Astelin®. Each dose consisted of two sprays/nostril. Serum FP and plasma AZE were followed over 24 (FP) and 120 h (AZE) and quantified by LC-MS/MS. Peak (Cmax) and total exposures AUC(0,tlast) were compared between the treatments by anova.
Study 1: Average FP Cmax was very low with all products (≤10 pg ml−1). FP AUC(0,tlast) point estimates (90% CIs) for MP29-02 : MP29-02-FP-mono and MP29-02 : FP-BI ratios (%) were 93.6 (83.6, 104.7) and 161.1 (137.1, 189.3). Corresponding ratios for Cmax were 91.0 (82.5, 100.4) and 157.4 (132.5, 187.1). Study 2: AZE AUC(0,tlast) point estimates (90% CIs) for MP29-02 : MP29-02-AZE-mono and MP29-02 : Astelin® ratios (%) were 98.8 (91.0, 107.4) and 105.5 (95.6, 116.4). Corresponding outcomes for Cmax were 102.7 (92.1, 114.4) and 107.3 (92.6, 124.3).
No interactions of AZE and FP were found with the MP29-02 formulation. Azelastine bioavailability was similar for MP29-02 and Astelin®. Maximum and total FP exposure was higher for MP29-02-based products compared with FP-BI. FP concentrations were generally very low with all investigational products and did not suggest clinically meaningful differences concerning systemic safety.
azelastine hydrochloride; bioavailability; drug–drug interaction; fluticasone propionate; nasal spray; pharmacokinetics
We set out to analyze the role of two major non-HLA gene polymorphisms associated with type 1 diabetes (T1D), PTPN22 1858C/T and insulin gene INS−23 A/T in progression to clinical T1D after the appearance of β-cell autoimmunity. The study population comprised 249 children with HLA-associated T1D susceptibility. All subjects were persistently positive for at least one of the T1D-associated biochemically defined autoantibodies (insulin autoantibody, GAD antibody, or IA-2 antibody), and 136 subjects presented with T1D over a median follow-up of 4.3 years (range 0.0–12.5) after the appearance of the first autoantibody. The PTPN22 1858T allele was strongly associated with progression to T1D after the appearance of the first biochemically defined β-cell autoantibody (hazard ratio 1.68 [95% CI 1.09–2.60], P = 0.02 Cox regression analysis, multivariate test), and the effect remained similar when analyzed after the appearance of the second autoantibody (P = 0.013), whereas INS−23 HphI AA genotype was not associated with progression to clinical diabetes after the appearance of the first or second autoantibody (P = 0.38 and P = 0.88, respectively). The effect of the INS risk genotype seems to be limited to the induction and early phases of β-cell autoimmunity, but the PTPN22 1858T allele instead affects the initiation and late progression phase of diabetes-associated autoimmunity.
At the moment, positive sentinel lymph node dissection (SLND) of the axilla is followed by axillary lymph node dissection (ALND) as standard of care. Recent data proves that omitting ALND after positive SLND in clinically lymph node-negative early stage breast cancer patients is feasible with low recurrence rates. The well known effect of radiotherapy to destroy occult tumor cells highly contributes to these results as a large extent of level I and II lymph nodes are unavoidably included in standard tangential radiation treatment fields. Reviewing the up to date published data on axillary lymph node treatment with radiotherapy, we hypothesize that full dosage coverage of level I and II of the axilla in early stage breast cancer will improve outcome and should be further evaluated.
Adjuvant treatment; Breast cancer; Curative radiotherapy; Sentinel lymph node
Class II alleles define the main HLA effect on type 1 diabetes, but there is an independent effect of certain class I alleles. Class II and class I molecules are differently involved in the initiation and effector phases of the immune response, suggesting that class I alleles would be important determinants in the rate of β-cell destruction. To test this hypothesis we analyzed the role of HLA class I and class II gene polymorphisms in the progression from diabetes-associated autoimmunity to clinical disease.
RESEARCH DESIGN AND METHODS
The effect of HLA-DR-DQ haplotypes and a panel of class I HLA-A and -B alleles on the progression from autoantibody seroconversion to clinical diabetes was studied in 249 children persistently positive for at least one biochemical diabetes-associated autoantibody in addition to islet cell autoantibody.
The progression to clinical disease was separately analyzed after the appearance of the first and the second persistent biochemical autoantibody using Cox regression. Multivariate analysis demonstrated a significant protective effect of the A*03 allele (odds ratio [OR] 0.61, P = 0.042 after the first and OR 0.55, P = 0.027 after the second autoantibody), whereas the B*39 allele had a promoting effect after seroconversion for the second autoantibody (OR 2.4, P = 0.014). When children with the DR3/DR4 genotype were separately analyzed, HLA-B*39 had a strong effect (OR 6.6, P = 0.004 and OR 7.5, P = 0.007, after the appearance of the first and the second autoantibody, respectively). The protective effect of A*03 was seen only among children without the DR3/DR4 combination.
These results confirm that class I alleles affect the progression of diabetes-associated autoimmunity and demonstrate interactions between class I and class II alleles.
To evaluate the psychological burden of parents facing increasing risk of type 1 diabetes in their children.
RESEARCH DESIGN AND METHODS
In the population-based Type 1 Diabetes Prediction and Prevention (DIPP) Study, newborn infants with HLA-DQB1–conferred diabetes risk were enrolled in sequential analyses of diabetes-associated autoantibodies. Those persistently positive for at least two autoantibodies were recruited to a randomized double-blinded intervention trial. The experience of stress in parents of 664 children was measured using Parenting Stress Index self-report inventory.
While diagnosis of diabetes increased parental stress, the appearance of autoantibodies or participation in the intervention trial did not. Mothers had higher stress levels than fathers. Single parenthood and chronically ill family members increased parental stress.
Parental stress was not increased by notification of autoantibody positivity or by participation in an intervention trial. Other demanding family conditions contributed to the experience of stress.
To evaluate the effect of co-administration of rifampicin, an inducer of cytochrome P450 (CYP)3A4, on the pharmacokinetics of roflumilast and roflumilast N-oxide. Roflumilast is an oral, once-daily phosphodiesterase 4 (PDE4) inhibitor, being developed for the treatment of chronic obstructive pulmonary disease. Roflumilast is metabolized by CYP3A4 and CYP1A2, with further involvement of CYP2C19 and extrahepatic CYP1A1. In vivo, roflumilast N-oxide contributes >90% to the total PDE4 inhibitory activity.
Sixteen healthy male subjects were enrolled in an open-label, three-period, fixed-sequence study. They received a single oral dose of roflumilast 500 µg on days 1 and 12 and repeated oral doses of rifampicin 600 mg once daily on days 5–15. Plasma concentrations of roflumilast and roflumilast N-oxide were measured for up to 96 h. Test/Reference ratios and 90% confidence intervals (CIs) of geometric means for AUC and Cmax of roflumilast and roflumilast N-oxide and for oral apparent clearance (CL/F) of roflumilast were estimated.
During the steady-state of rifampicin, the AUC0–∞ of roflumilast decreased by 80% (point estimate 0.21; 90% CI 0.16, 0.27); Cmax by 68% (0.32; CI 0.26, 0.39); for roflumilast N-oxide, the AUC0–∞ decreased by 56% (0.44; CI 0.36, 0.55); Cmax increased by 30% (1.30; 1.15, 1.48); total PDE4 inhibitory activity decreased by 58% (0.42; 0.38, 0.48).
Co-administration of rifampicin and roflumilast led to a reduction in total PDE4 inhibitory activity of roflumilast by about 58%. The use of potent cytochrome P450 inducers may reduce the therapeutic effect of roflumilast.
CYP3A induction; drug–drug interaction; PDE4 inhibitor; pharmacokinetics; rifampicin; roflumilast
Transcriptional co-repressors of the Groucho/transducin-like Enhancer of split (Gro/TLE) family regulate the expression of a variety of genes and are involved in numerous developmental processes in both invertebrate and vertebrate species. More specifically, Gro/TLE1 participates in mechanisms that inhibit/delay the differentiation of cerebral cortex neural progenitor cells into neurons during mammalian forebrain development. The anti-neurogenic function of Gro/TLE1 depends on the formation of protein complexes with specific DNA-binding transcription factors that engage Gro/TLE1 through WRP(W/Y) sequences. Interaction with those transcription partners results in Gro/TLE1 recruitment to selected DNA sites and causes increased Gro/TLE1 phosphorylation. The physiological significance of the latter event, termed “cofactor-activated phosphorylation,” had not been determined. Therefore, this study aimed at clarifying the role of cofactor-activated phosphorylation in the anti-neurogenic function of Gro/TLE1.
Methods and Principal Findings
A combination of site-directed mutagenesis, mass spectrometry, biochemistry, primary cell culture, and immunocytochemical assays was utilized to characterize point mutations of Ser-286, a residue that is phosphorylated in vivo and is located within the serine/proline-rich (SP) domain of Gro/TLE1. Mutation of Ser-286 to alanine or glutamic acid does not perturb the interaction of Gro/TLE1 with DNA-binding partners, including the basic helix-loop-helix transcription factor Hes1, a prototypical anti-neurogenic WRP(W/Y) motif protein. Ser-286 mutations do not prevent the recruitment of Gro/TLE1 to DNA, but they impair cofactor-activated phosphorylation and weaken the interaction of Gro/TLE1 with chromatin. These effects are correlated with an impairment of the anti-neurogenic activity of Gro/TLE1. Similar results were obtained when mutations of Ser-289 and Ser-298, which are also located within the SP domain of Gro/TLE1, were analyzed.
Based on the positive correlation between Gro/TLE1 cofactor-activated phosphorylation and ability to inhibit cortical neuron differentiation, we propose that hyperphosphorylation induced by cofactor binding plays a positive role in the regulation of Gro/TLE1 anti-neurogenic activity.
To evaluate toxicity of radiochemotherapy schedule using daily-low-dose-cisplatin in radiochemotherapy of locally-advanced head-and-neck-cancer (HNSCC).
Methods and patients
From October 2003 to October 2006, 50 patients with HNSCC (stage III/IVA/IVB) were treated. In 32 patients, surgery and adjuvant radiotherapy(64 Gy), in 18 patients definitive radiotherapy(70 Gy) was performed. Low-dose-cisplatin was applied concomitantly (6 mg/m2/every radiotherapy-day).
Acute toxicity ≥grade 3 was observed in 22 patients (11 patients mucositis/dysphagia, 7 hematologic toxicity, 4 mucositis/dysphagia/hematologic toxicity). 90% of our patients received >80% of the planned cumulative chemotherapy dose, 94% the intended dose of radiotherapy. After median follow-up of 24.2 months, 3-year overall survival and loco-regional control rates were 67.1 and 78%. During follow-up, chronic toxicity ≥grade 3 (xerostomia, subcutaneous fibrosis, or lymphedema) was observed in nine patients.
We found chemoradiation with daily-low-dose-cisplatin to be feasible with advantage of low acute and chronic toxicity. Therefore, use of low-dose-cisplatin should be evaluated in future clinical trials.
Low dose cisplatin; HNSCC; Radiochemotherapy; Toxicity
As the majority of prostate cancers (PC) express estrogen receptors, we evaluated the combination of radiation and estrogenic stimulation (estrogen and genistein) on the radiosensitivity of PC cells in vitro.
PC cells LNCaP (androgen-sensitive) and PC-3 (androgen-independent) were evaluated. Estrogen receptor (ER) expression was analyzed by means of immunostaining. Cells were incubated in FCS-free media with genistein 10 μM and estradiol 10 μM 24 h before irradiation and up to 24 h after irradiation. Clonogenic survival, cell cycle changes, and expression of p21 were assessed.
LNCaP expressed both ER-α and ER-β, PC-3 did not. Incubation of LNCaP and PC-3 with genistein resulted in a significant reduction of clonogenic survival. Incubation with estradiol exhibited in low concentrations (0.01 μM) stimulatory effects, while higher concentrations did not influence survival. Both genistein 10 μM and estradiol 10 μM increased low-dose hyper-radiosensitivity [HRS] in LNCaP, while hormonal incubation abolished HRS in PC-3. In LNCaP cells hormonal stimulation inhibited p21 induction after irradiation with 4 Gy. In PC-3 cells, the proportion of cells in G2/M was increased after irradiation with 4 Gy.
We found an increased HRS to low irradiation doses after incubation with estradiol or genistein in ER-α and ER-β positive LNCaP cells. This is of high clinical interest, as this tumor model reflects a locally advanced, androgen dependent PC. In contrast, in ER-α and ER-β negative PC-3 cells we observed an abolishing of the HRS to low irradiation doses by hormonal stimulation. The effects of both tested compounds on survival were ER and p53 independent. Since genistein and estradiol effects in both cell lines were comparable, neither ER- nor p53-expression seemed to play a role in the linked signalling. Nevertheless both compounds targeted the same molecular switch. To identify the underlying molecular mechanisms, further studies are needed.
What is already known about this subject
Cytochrome P450 (CYP) 3A4 plays a prominent role in the metabolism of many drugs, which in turn implies, that changes in the activity of this enzyme caused by, for example, co-administered drugs, might result in clinically significant drug interactions.Roflumilast, a targeted PDE4 inhibitor in clinical development for the treatment of COPD and asthma, is partly metabolized by CYP3A4, and thus may have the potential to inhibit its activity.
What this study adds
The results of this study show that therapeutic steady-state concentrations of roflumilast and its active metabolite roflumilast N-oxide do not alter the disposition of the CYP3A substrate midazolam.Therefore, roflumilast treatment has a low susceptibility to alter the clearance of drugs metabolized by CYP3A4.
The aim of this study was to investigate the effects of roflumilast, an investigational PDE4 inhibitor for the treatment of COPD and asthma, on the pharmacokinetics of the CYP3A probe drug midazolam and its major metabolites.
In an open, randomized (for midazolam treatment sequence) study, 18 healthy male subjects received single doses of midazolam (2 mg oral and 1 mg i.v., 1 day apart) alone, repeated doses of roflumilast (500 µg once daily for 14 days) alone, and repeated doses of roflumilast together with single doses of midazolam (2 mg oral and 1 mg i.v., 1 day apart).
A comparison of clearance and peak and systemic exposure to midazolam following administration of roflumilast indicated no effect of roflumilast dosed to steady state on the pharmacokinetics of midazolam. Point estimates (90% CI) were 0.97 (0.84, 1.13) for the AUC of i.v. midazolam and 0.98 (0.82, 1.17) for that of oral midazolam with and without roflumilast.
Therapeutic steady state concentrations of roflumilast and its N-oxide do not alter the disposition of the CYP3A substrate midazolam in healthy subjects. This finding suggests that roflumilast is unlikely to alter the clearance of drugs that are metabolized by CYP3A4.
CYP3A substrate; drug–drug interaction; midazolam; PDE4 inhibitor; pharmakokinetics; roflumilast
Oncological results of radiotherapy for locally advanced prostate cancer (PC) are significantly improved by simultaneous application of LHRH analoga (e.g. goserelin). As 85% of PC express LHRH receptors, we investigated the interaction of goserelin incubation with radiotherapy under androgen-deprived conditions in vitro.
LNCaP and PC-3 cells were stained for LHRH receptors. Downstream the LHRH receptor, changes in protein expression of c-fos, phosphorylated p38 and phosphorylated ERK1/2 were analyzed by means of Western blotting after incubation with goserelin and irradiation with 4 Gy. Both cell lines were incubated with different concentrations of goserelin in hormone-free medium. 12 h later cells were irradiated (0 – 4 Gy) and after 12 h goserelin was withdrawn. Endpoints were clonogenic survival and cell viability (12 h, 36 h and 60 h after irradiation).
Both tested cell lines expressed LHRH-receptors. Changes in protein expression demonstrated the functional activity of goserelin in the tested cell lines. Neither in LNCaP nor in PC-3 any significant effects of additional goserelin incubation on clonogenic survival or cell viability for all tested concentrations in comparison to radiation alone were seen.
The clinically observed increase in tumor control after combination of goserelin with radiotherapy in PC cannot be attributed to an increase in radiosensitivity of PC cells by goserelin in vitro.
Miniaturized growth systems for heterogeneous culture collections are not only attractive in reducing demands for incubation space and medium but also in making the parallel handling of large numbers of strains more practicable. We report here on the optimization of oxygen transfer rates in deep-well microtiter plates and the development of a replication system allowing the simultaneous and reproducible sampling of 96 frozen glycerol stock cultures while the remaining culture volume remains frozen. Oxygen transfer rates were derived from growth curves of Pseudomonas putida and from rates of oxygen disappearance due to the cobalt-catalyzed oxidation of sulfite. Maximum oxygen transfer rates (38 mmol liter−1 h−1, corresponding to a mass transfer coefficient of 188 h−1) were measured during orbital shaking at 300 rpm at a shaking diameter of 5 cm and a culture volume of 0.5 ml. A shaking diameter of 2.5 cm resulted in threefold-lower values. These high oxygen transfer rates allowed P. putida to reach a cell density of approximately 9 g (dry weight) liter−1 during growth on a glucose mineral medium at culture volumes of up to 1 ml. The growth-and-replication system was evaluated for a culture collection consisting of aerobic strains, mainly from the genera Pseudomonas, Rhodococcus, and Alcaligenes, using mineral media and rich media. Cross-contamination and excessive evaporation during vigorous aeration were adequately prevented by the use of a sandwich cover of spongy silicone and cotton wool on top of the microtiter plates.