The checkpointkinase 2 (CHK2) 1100delC germ line mutation is not associated with the development of squamous cell carcinoma of the head and neck (SCCHN)

Background  

The checkpointkinase 2 (CHK2) is part of the highly conserved ATM-CHK2 signaling pathway, which is activated in response to DNA damage, in particular after double strand breaks which can be caused by carcinogens like smoking. After induction of downstream targets, e.g. the tumor suppressor p53, its activation leads to cell cycle arrest and apoptosis. Recently, the presence of CHK2 germ line mutations, primarily the 1100delC variant, has been reported to be involved in carcinogenesis. The CHK2 1100delC variant results in a truncated protein which is instable and inactive. Carriers of this variant have been shown to have an increased risk to develop breast cancer and probably also other tumors. Our purpose was to investigate the role of CHK2 germ line mutations in patients with squamous cell carcinoma of the head and neck (SCCHN).     

Single nucleotide polymorphisms of the vascular endothelial growth factor gene associated with incidence of oral squamous cell carcinoma

J Oral Pathol Med (2010) 39 : 786–792 Background: Vascular endothelial growth factor (VEGF) plays an important role in promoting angiogenesis and is overexpressed in several malignancies. Polymorphisms of the VEGF gene can alter VEGF protein expression, which may be biologically significant and account for heterogeneity in disease risk and outcome. The aim of this case–control study was to evaluate potential associations between single nucleotide polymorphisms (SNP) of the VEGF gene with susceptibility of oral squamous cell carcinoma (OSCC). Patients and methods: Five VEGF SNP (?1154 G/A, +405 G/C, +936 C/T, ?2578 C/A and ?460 C/T) were determined in peripheral blood isolated from 80 patients with OSCC and from 40 age‐ and gender‐matched healthy volunteers (RT‐PCR). Results: The +936 T allele and the ?2578 C/A SNP were expressed significantly more often in the OSCC‐group (P = 0.002; P < 0.0001) where three associations between two SNPs (+936 and +405, ?2578 and ?1154, ?460 and ?2578) were found. Conclusion: Our findings provide support that +936 T allele and ?2578 C/A SNP of the VEGF gene alone or in combination with other SNP are associated with OSCC. The SNPs may be used as biomarker for the development of specialized anti‐VEGF drugs. Further studies must confirm the value of preoperative genetic analysis for prognosis.     

Targeting the phosphoinositide 3-kinase isoform p110delta impairs growth and survival in neuroblastoma cells.

PURPOSE: The phosphoinositide 3-kinase (PI3K)/Akt pathway is frequently activated in human cancer and plays a crucial role in neuroblastoma biology. We were interested in gaining further insight into the potential of targeting PI3K/Akt signaling as a novel antiproliferative approach in neuroblastoma. EXPERIMENTAL DESIGN: The expression pattern and functions of class I(A) PI3K isoforms were investigated in tumor samples and cell lines. Effects on cell survival and downstream signaling were analyzed following down-regulation of p110alpha or p110delta in SH-SY5Y and LA-N-1 cells by means of RNA interference. RESULTS: Overexpression of the catalytic p110delta and regulatory p85alpha isoforms was detected in a panel of primary neuroblastoma samples and cell lines, compared with normal adrenal gland tissue. Although down-regulation of either p110alpha or p110delta led to impaired cell growth, reduced expression of p110delta also had a selective effect on the survival of SH-SY5Y cells. Decreased levels of p110delta were found to induce apoptosis and lead to lower expression levels of antiapoptotic Bcl-2 family proteins. SH-SY5Y cells with decreased p110delta levels also displayed reduced activation of ribosomal protein S6 kinase in response to stimulation with epidermal growth factor and insulin-like growth factor-I. CONCLUSIONS: Together, our data reveal a novel function of p110delta in neuroblastoma growth and survival.     

Kontroversen bei der Standardisierung der Empfindlichkeits-prüfung von Hefen gegen Azol-Antimyotika

Zusammenfassung. Die unterschiedlichen physikalisch-chemischen Eigenschaften der therapeutisch ein-gesetzten Azol-Antimykotika erfordern ein Testverfahren, welches diesen gerecht wird. Fluconazol kann innerhalb der Gruppe der Azol-Antimykotika aufgrund seiner Hydrophilie als unproblematische Testsubstanz angesehen werden. Die extreme Hydrophobizität des Itraconazols läßt eine Übertragung der Testbedingungen für Fluconazol auf die Itraconazoltestung nicht zu. Die aktuellen Empfehlungen des NCCLS werden dieser Problematik nicht gerecht. Deshalb ist es notwendig, einen einheitlichen Standard für die In-vitro-Testung der Gruppe der Azol-Antimykotika festzulegen.
Summary. Due to the different physical-chemical conditions of the therapeutical azoles it is necessary to choose an adequate testing procedure. In the group of azoles caused by its hydrophilia fluconazole susceptibility testing can be handled easily. However it is not possible to take the same test conditions for itraconazole as for fluconazole due to the extreme high hydrophobicity of itraconazole. The current recommendations of NCCLS should be considering these problems. Therefore it is necessary to standardize susceptibility testing for all azoles possible.     

Hydrolytically activated etoposide prodrugs inhibit MDR-1 function and eradicate established MDR-1 multidrug-resistant T-cell leukemia

Effective therapy of high-risk leukemia with established cytotoxic drugs may be limited by poor antitumor efficacy, systemic toxicity, and the induction of drug resistance. Here, we provide the first evidence that hydrolytically activated prodrugs may overcome these problems. For this purpose, VP16 was functionally blocked by hydrolytically cleavable carbonate linkers with unique characteristics to generate 2 novel prodrugs of VP16. First, we established a more than 3-log higher efficacy of the 2 prodrugs compared with VP16 on a panel of naturally drug-resistant tumor cell lines. Second, the prodrugs did overcome VP16-induced multidrug resistance-1 gene (MDR-1)-mediated multidrug resistance in vitro in a newly established VP16-resistant T-cell leukemia cell line MOVP-3 by functionally blocking MDR-1-mediated efflux. Third, in vivo studies showed a maximum tolerated dose of ProVP16-II (> 45mg/kg), which was at least 3-fold higher than that of VP16 (15 mg/kg). Finally, tests of ProVP16-II in a multidrug-resistant xenograft model of T-cell leukemia expressing MDR-1 indicated that only the mice treated with this prodrug revealed a complete and long-lasting regression of established, drug-resistant leukemia. In summary, the hydrolytically activated etoposide prodrugs proved effective against multidrug-resistant T-cell leukemia in vitro and in vivo and provide proof of concept for a highly promising new strategy for the treatment of MDR-1 drug-resistant malignancies.     

Mercapturate metabolism of 4-hydroxy-2-nonenal in rat and human cerebrum

4-Hydroxy-2-nonenal (HNE), a potent toxin formed in the brain from oxidation of polyunsaturated fatty acids, is increased in Alzheimer disease (AD), where it is a proposed effector of amyloid beta peptide-mediated neurotoxicity. Detoxification of HNE via the mercapturic acid pathway (MAP) is the primary means by which other organs, such as liver, limit its toxic effects. Here we examined the distribution and activity of MAP detoxification for HNE in cerebrum. Our results showed that rat cerebral cortex and especially synaptosomes were less well equipped to detoxify HNE via the MAP than liver. Glutathione transferases (GSTs) catalyze the committed step in the MAP; GST-mu and GST-pi, but not OST-alpha, were detected in neurons and astrocytes in cerebrum from AD patients and controls. MAP activity in frontal cortex of AD patients was modestly but significantly increased compared to controls. These data suggest that lipid peroxidation may present a greater toxic burden to cerebrum than to other organs, and that a component of response to injury in late stage AD is a slight increase in MAP activity.