Claas Brockschmidt

The Role of the Casein Kinase 1 (CK1) Family in Different Signaling Pathways Linked to Cancer Development

The members of the casein kinase 1 (CK1) family are highly conserved and are expressed in many eukaryotes ranging from yeast to humans. Mammalian CK1 isoforms (a, ß, ?, d, e) and their splice variants are involved in diverse cellular processes including membrane trafficking, circadian rhythm, cell cycle progression, chromosome segregation, apoptosis and cellular differentiation. Mutations and deregulation of CK1 expression and activity has been linked to various diseases including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease, sleeping disorders and proliferative diseases such as cancer. In this review, we summarize the functions of CK1 and outline the participation of CK1 in signal transduction pathways linked to cancer development.

Anti-apoptotic and growth-stimulatory functions of CK1 delta and epsilon in ductal adenocarcinoma of the pancreas are inhibited by IC261 in vitro and in vivo

Background: Pancreatic ductal adenocarcinomas (PDACs) are highly resistant to treatment due to changes in various signalling pathways. CK1 isoforms play important regulatory roles in these pathways. Aims: We analysed the expression levels of CK1 delta and epsilon (CK1δ/∊) in pancreatic tumour cells in order to validate the effects of CK1 inhibition by 3-[2,4,6-(trimethoxyphenyl)methylidenyl]-indolin-2-one (IC261) on their proliferation and sensitivity to anti-CD95 and gemcitabine. Methods: CK1δ/∊ expression levels were investigated by using western blotting and immunohistochemistry. Cell death was analysed by FACS analysis. Gene expression was assessed by real-time PCR and western blotting. The putative anti-tumoral effects of IC261 were tested in vivo in a subcutaneous mouse xenotransplantation model for pancreatic cancer. Results: We found that CK1δ/∊ are highly expressed in pancreatic tumour cell lines and in higher graded PDACs. Inhibition of CK1δ/∊ by IC261 reduced pancreatic tumour cell growth in vitro and in vivo. Moreover, IC261 decreased the expression levels of several anti-apoptotic proteins and sensitised cells to CD95-mediated apoptosis. However, IC261 did not enhance gemcitabine-mediated cell death either in vitro or in vivo. Conclusions: Targeting CK1 isoforms by IC261 influences both pancreatic tumour cell growth and apoptosis sensitivity in vitro and the growth of induced tumours in vivo, thus providing a promising new strategy for the treatment of pancreatic tumours.

Population Pharmacokinetics and Target Attainment of Meropenem in Plasma and Tissue of Morbidly Obese Patients after Laparoscopic Intraperitoneal Surgery.

ABSTRACT Meropenem serves as a clinically important, broad-spectrum antibiotic. While meropenem is commonly used in obese patients, its pharmacokinetics in this patient group is not well known. Our aim was to characterize the population pharmacokinetics and target attainment in plasma, subcutaneous tissue, and peritoneal fluid for meropenem in morbidly obese patients. Four doses of 1g meropenem were given as 15-min infusions every 8 h to five morbidly obese patients (body mass index [BMI], 47.6 to 62.3 kg/m2). After the fourth dose, serial meropenem concentrations were determined in plasma and, via microdialysis, in subcutaneous tissue and peritoneal fluid. All concentrations were analyzed simultaneously via population modeling, and target attainment probabilities predicted via Monte Carlo simulations using the target of unbound meropenem concentrations above the MIC for at least 40% of the dosing interval. For patients with 53 kg fat-free mass, total clearance was 18.7 liters/h and volume of distribution at steady state was 27.6 liters. The concentrations in subcutaneous tissue and peritoneal fluid largely paralleled those in plasma (equilibration half-life, <30 min). The area under the curve (AUC) in subcutaneous tissue divided by the plasma AUC had a mean of 0.721. For peritoneal fluid, this AUC ratio had a mean of 0.943. Target attainment probabilities were >90% after 1 g meropenem every 8 h as a 15-min infusion for MICs of up to 2 mg/liter in plasma and peritoneal fluid and 0.5 mg/liter in subcutaneous tissue. Meropenem pharmacokinetics in plasma and peritoneal fluid of obese patients was predictable, but subcutaneous tissue penetration varied greatly. (This study has been registered at ClinicalTrials.gov under registration no. NCT01407965.)

Pharmacokinetics of Ertapenem in Colorectal Tissue

Background: There are only limited data on tissue kinetics of ertapenem in colorectal tissue more than 3 h after administration of the drug. The purpose of this study was to assess the pharmacokinetics (PK) of ertapenem in colorectal tissue via population PK modeling. Patients and Methods: Patients ≧18 years requiring surgical intervention at the colon and/or rectum were eligible (ClinicalTrials.gov identifier: NCT 00535652). Tissue and blood samples were taken during surgery after a single dose of 1 g ertapenem. Ertapenem concentration was determined by high-performance liquid chromatography/mass spectrometry. Population PK modeling was performed in S-ADAPT. Results: Twenty-three patients were enrolled. The highest tissue concentration was 6.4 ± 2.3 mg/kg, the highest total plasma concentration 51.34 ± 9.4 mg/l, the highest unbound plasma concentration 7.05 ± 1.1 mg/l, and the unbound fraction in plasma was 14–15% for total ertapenem concentrations below approximately 22 mg/l, 19% at 100 mg/l, and 25% at 250 mg/l. The estimated geometric mean terminal half-life was 2.5 h for plasma and tissue. In the Monte Carlo simulation, a single dose of 1,000 mg ertapenem achieved robust (≧90%) probabilities of target attainment up to a minimum inhibitory concentration (MIC) of approximately 2 mg/l for the bacteriostasis target (free time above MIC, fT>MIC = 20%) and up to 0.25–0.5 mg/l for the near-maximal killing target (40% fT>MIC). Conclusion: Our data indicate an adequate penetration of ertapenem into uninfected colorectal tissue up to 8.5 h (35% of the dosing interval) after administration of 1 g intravenously.

The Minimal-Access Kidney Transplantation Technique in Living-Donor Transplantation: Results From a Retrospective Analysis

OBJECTIVES During the last 15 years, there was tremendous progress in minimally invasive surgery and minimal-access surgery. Many conventional surgical procedures were replaced by these techniques, resulting in a wide range of benefits for the patients. In kidney transplantation, many centers choose an approach to the iliac fossa through an oblique or J-shaped incision. This might have possible disadvantages due to the extent of tissue trauma. Thus, we introduced a minimal-access kidney transplantation technique (MAKT) as a transplantation method in our center. We retrospectively analyzed this technique used for 11 living-donor kidney transplants and report here our experience. PATIENTS AND METHODS From April 2008 to July 2011, 11 living-donor kidney recipients were subjected to the MAKT and were matched (age, sex) with a historical group from our center from 2000 to 2007. To analyze the assumption of noninferiority of the MAKT in comparison to the standard approach, a matched case-control study design was chosen, with creatinine level at 1 year after transplantation as the primary outcome variable. We used a Wilcoxon signed rank test; 1-sided significance level was 2.5%. RESULTS Eleven recipients were included. Both groups were almost similar regarding age and body mass index. Characteristics of the procedure were significantly different only for cold ischemic time (114 minutes MAKT vs 77 minutes historical group). In the MAKT group, there were no reinterventions necessary, no wound infections, no incisional hernia, no acute rejection episodes, no graft losses, and 2 lymphoceles occurred. Further, no urinary leakage or ureteral stenosis and no vascular complications were observed. The statistical analysis of the primary endpoint revealed a noninferiority of the MAKT technique (P = .0005). CONCLUSIONS Considering the fact that this is an initial series and a retrospective analysis, the applied MAKT technique seems to be safe in terms of both graft function after 1 year and surgical complications.

Laparoscopic intraperitoneal mesh fixation with fibrin sealant of a Spigelian hernia.

Spigelian hernia is a rare clinical entity and has a subtle clinical presentation with vague abdominal pain, which can cause an important delay in diagnosis. Given the relatively high risk of incarceration the diagnosis of Spigelian hernia is an indication for surgical repair. Laparoscopic Spigelian mesh herniorraphy has gained recognition as an effective tension-free method and is associated with lower recurrence. Appropriate fixation techniques are however required to reduce complications such as nerve irritation, hematoma, and postoperative chronic pain. In this case report we describe a novel approach in laparoscopic mesh repair of Spigelian hernia, securing a lightweight composite mesh with fibrin sealant. This fixation seems to be a reasonable, feasible alternative to the standard tissue-penetrating mesh fixation.

Laparoscopic splenectomy of a wandering spleen with coincidental enormous splenomegaly.

Ectopy of the spleen also referred to as wandering spleen is a rare condition and preferentially treated by laparoscopic splenopexy. However, in complicated cases with torsion and consecutive infarction of the spleen splenectomy is required. Performing the splenectomy of a wandering spleen laparoscopically has already been reported as a save therapeutic option. However, open splenectomy is usually preferred in case of massive splenomegaly for both, wandering and regular localized spleen. In this case report we describe a laparoscopic technique as alternative for conventional splenectomy in the case of a huge wandering spleen.

Beeinflussung der Spindeldynamik durch CK1 Inhibitoren alleine und in Kombination mit Spindelgiften: Ein Ansatzpunkt für die Entwicklung neuer Konzepte in der Tumortherapie?

Members of the CK1 family are involved in the regulation of many different biological processes. Therefore, they are attractive targets for the development of new inhibitors. CK1 specific inhibitors might provide a powerful tool in treating various diseases, including cancer.