Novel PRRT2 mutations in paroxysmal dyskinesia patients with variant inheritance and phenotypes

Paroxysmal dyskinesias (PDs) are a group of episodic movement disorders with marked variability in clinical manifestation and potential association with epilepsy. PRRT2 has been identified as a causative gene for PDs, but the phenotypes and inheritance patterns of PRRT2 mutations need further clarification. In this study, 10 familial and 21 sporadic cases with PDs and PDs-related phenotypes were collected. Genomic DNA was screened for PRRT2 mutations by direct sequencing. Seven PRRT2 mutations were identified in nine (90.0%) familial cases and in six (28.6%) sporadic cases. Five mutations are novel: two missense mutations (c.647C>G/p.Pro216Arg and c.872C>T/p.Ala291Val) and three truncating mutations (c.117delA/p.Val41TyrfsX49, c.510dupT/p.Leu171SerfsX3 and c.579dupA/p.Glu194ArgfsX6). Autosomal dominant inheritance with incomplete penetrance was observed in most of the familial cases. In the sporadic cases, inheritance was heterogeneous including recessive inheritance with compound heterozygous mutations, inherited mutations with incomplete parental penetrance and de novo mutation. Variant phenotypes associated with PRRT2 mutations, found in 36.0% of the affected cases, included febrile convulsions, epilepsy, infantile non-convulsive seizures (INCS) and nocturnal convulsions (NC). All patients with INCS or NC, not reported previously, displayed abnormalities on electroencephalogram (EEG). No EEG abnormalities were recorded in patients with classical infantile convulsions and paroxysmal choreoathetosis (ICCA)/paroxysmal kinesigenic dyskinesia (PKD). Our study further confirms that PRRT2 mutations are the most common cause of familial PDs, displaying both dominant and recessive inheritance. Epilepsy may occasionally occur in ICCA/PKD patients with PRRT2 mutations. Variant phenotypes INCS or NC differ from classical ICCA/PKD clinically and electroencephalographically. They have some similarities with, but not identical to epilepsy, possibly represent an overlap between ICCA/PKD and epilepsy.

Mosaic SCN1A mutations in familial partial epilepsy with antecedent febrile seizures

SCN1A is the most relevant epilepsy gene. Mutations of SCN1A generate phenotypes ranging from the extremely severe form of Dravet syndrome (DS) to a mild form of generalized epilepsy with febrile seizures plus (GEFS+). Mosaic SCN1A mutations have been identified in rare familial DS. It is suspected that mosaic mutations of SCN1A may cause other types of familial epilepsies with febrile seizures (FS), which are more common clinically. Thus, we screened SCN1A mutations in 13 families with partial epilepsy with antecedent febrile seizures (PEFS+) using denaturing high-performance liquid chromatography and sequencing. The level of mosaicism was further quantified by pyrosequencing. Two missense SCN1A mutations with mosaic origin were identified in two unrelated families, accounting for 15.4% (2/13) of the PEFS+ families tested. One of the mosaic carriers with ~25.0% mutation of c.5768A>G/p.Q1923R had experienced simple FS; another with ~12.5% mutation of c.4847T>C/p.I1616T was asymptomatic. Their heterozygous children had PEFS+. Recurrent transmission occurred in both families, as noted in most of the families with germline mosaicism reported previously. The two mosaic mutations identified in this study are less destructive missense, compared with the more destructive truncating and splice-site mutations identified in the majority of previous studies. This is the first report of mosaic SCN1A mutations in families with probands that do not exhibit DS, but manifest only a milder phenotype. Therefore, such families with mild cases should be approached with caution in genetic counseling and the possibility of mosaicism origin associated with high recurrence risk should be excluded.

Design, synthesis and antitumor activity of novel artemisinin derivatives using hybrid approach

In an attempt to develop potent and selective anti-tumor agents, two novel series of artemisinin-chalcone hybrids were designed, synthesized and screened for their antitumor activities against HT-29, A549, MDA-MB-231, HeLa and H460 cell lines in vitro. Nearly all of the tested compounds showed significantly increased anti-tumor activity compared with the corresponding dihydroartemisinin (DHA). Most of the title compounds displayed good selectivity toward HT-29 and HeLa cell lines with IC₅₀ values ranging from 0.09 to 0.85 µM. Among them, the most promising compound 9c (IC₅₀) range of 0.09-0.93 µM) was 10.5- to 70-times more active than DHA (IC₅₀ range of 5.6-15.6 µM) respectively.

Impact of luteolin on the production of alpha-toxin by Staphylococcus aureus

AIMS

To investigate the influence of subinhibitory concentrations of luteolin on the production of α-toxin in Staphylococcus aureus.

METHODS AND RESULTS

The minimal inhibitory concentrations (MICs) were determined using a broth microdilution method, and the MICs of luteolin against the tested Staph. aureus strains ranged from 16 to 64 μg ml(-1). Haemolysis, Western blot and real-time reverse transcription (RT)-PCR assays were used to evaluate the effect of luteolin on Staph. aureusα-toxin secretion and on the level of gene expression, respectively. The data indicated that subinhibitory concentrations of luteolin dose dependently decreased the production of α-toxin in both meticillin-sensitive Staph. aureus (MSSA) and meticillin-resistant Staph. aureus (MRSA). Furthermore, the transcriptional levels of agr (accessory gene regulator) in Staph. aureus were also inhibited by luteolin.

CONCLUSIONS

Luteolin decreases the production and/or secretion of α-toxin in Staph. aureus; the reduced production may be dependent, in part, upon the luteolin-induced inhibition of the agr locus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The findings indicate that luteolin may be used as a basis for the development of antimicrobial agents aimed at bacterial virulence factors.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis

BACKGROUND AND OBJECTIVE

Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear.

MATERIAL AND METHODS

The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8.

RESULTS

The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15).

CONCLUSION

These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.

Gene expression profile in the liver tissue of geese after overfeeding

Geese form a fatty liver after feeding on a carbohydrate-rich diet, possibly as an evolutionary adaptation to accumulate reserves for migration. To gain insight into the gene-regulation processes of hepatic steatosis in geese, we examined the profile of transcriptional expression in goose fatty liver and control liver by suppression subtractive hybridization and measured the levels of serum biochemical variables. We found 107 genes whose expression was different between the treatment and control groups. The main functions of these genes are metabolic processes, including the metabolism of carbohydrates, amino acids, and lipids. Twenty-four genes were classified using the Kyoto Encyclopaedia of Genes and Genomes pathways. Twelve genes that related to metabolic and cellular processes were confirmed by quantitative RT-PCR. A specific positive effect of feeding was observed on the expression of genes involved mainly in unsaturated fatty acids and triglyceride synthesis, and a negative effect was observed on genes involved in β-oxidation, cholesterol metabolism, and glycolysis. The results could serve as an important reference for the development of goose breeding for fatty liver production and human liver disease research.

Abstract P1-14-01: Phosphatidylinositol 3-Kinase (PI3K) Pathway Activation in Breast Cancer Brain Metastases

Background:

Brain metastases (BM) are a devastating consequence of advanced breast cancer (BC) for which novel, targeted therapies are urgently needed. The PI3K pathway plays a critical role in the initiation and progression of BC. Alterations in this pathway are implicated in approximately 50% of BC. The role of PI3K activation in BCBM has yet to be explored. Material and Methods:

Under IRB approval (UNC and Duke), we established a clinically-annotated tumor bank including 54 BCBM and 15 matched primary BC. Activation of the PI3K pathway including pAKT, pS6K, and PTEN was assessed via immunohistochemistry (IHC, score 0-3+). BC subtype was assigned by IHC: HR+ (hormone receptor, ER+ and/or PR+)/HER2-, triple-negative (TN; ER-/PR-/HER2-), and HR +or-/HER2+. Overall survival (OS), recurrence patterns and survival following BM was evaluated by the Kaplan-Meier method and compared by the log-rank test.

Results:

Median age was 48 years (range 26-72). Sixty-eight percent of patients (pts) were Caucasian, 30% African-American, and 2% other ethnicities. At median follow-up of 5.9 years (yrs), 70% (38/54) of pts had died. BC subtype was confirmed among 47 pts: 30% (14/47) HR+/HER2-, 45% (21/47) TN and 25% (12/47) HR +or-/HER2+. Subtype concordance between primary BC and BM was 89% (8/9). High expression (IHC score 2-3+) of pAKT and pS6K was observed in 50% (27/54) and 72% (38/54) of the BCBM, respectively. Low expression of PTEN (IHC score 0-1) was observed in 31% (17/54) of BCBM. Concordance of PI3K biomarkers between primary BC and matched BCBM was 47% (7/15), 40% (6/15) and 80% (12/15) for pAKT, pS6K and PTEN, respectively. Both gain and loss of protein expression between primary BC and BCBM was observed in each biomarker evaluated. No significant correlation between BC subtypes and activation status of the PI3K pathway (IHC score 0-1 vs. 2-3+) was observed for pAKT, pS6K or PTEN. Median OS was 7.09 yrs (3.52, 9.21), 4.27 yrs (95% CI 1.84, 5.18), and not reached (NR) for HR+/HER2-, TN and HR +or-/HER2+, respectively (p=0.009). Median OS after BCBM diagnosis was 1.54 yrs (0.27, 2.45), 0.91 yrs (0.51, 1.49) and NR for HR+/HER2-, TN and HR +or-/HER2+, respectively (p=0.0003). Expression (0-1+ vs. 2-3+) of pAKT and pS6K in BCBM was not predictive of OS, time to BCBM recurrence or survival after BCBM (all P>0.1). Although not predictive of inferior survival following BCBM (1.2 vs. 1.5 yrs, p=0.7), low expression (0-1+ vs. 2-3+) of PTEN in BCBM predicted for inferior OS from primary BC diagnosis (5.1 vs. 6.3 yrs, p=0.03) and shorter time to BCBM (2.5 vs. 3.4 yrs, p=0.008). Conclusions:

The PI3K pathway is active in most BCBM regardless of subtype. Considerable discordance exists between PI3K pathway biomarkers in the primary BC and BCBM from the same patient. Low expression of PTEN in BCBM may be prognostic. Given that small molecule inhibitors of the PI3K pathway in clinical development cross the blood brain barrier, inhibition of the PI3K pathway represents a promising therapeutic strategy for a group of patients whose prognosis is poor and for whom systemic therapies are limited.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-14-01.

Inhibition of autophagy induced by overexpression of mda-7/interleukin-24 strongly augments the antileukemia activity in vitro and in vivo

Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a novel candidate of tumor suppressor that can selectively induce apoptosis experimentally in a spectrum of human cancer cells including leukemia cells. However, a recent study suggests that mda-7/IL-24 promotes the survival of chronic lymphocytic leukemia B-cells. In this study, we showed that mda-7/IL-24 was constitutively expressed in leukemia cell lines and primary acute myeloid leukemia samples. Using a conditionally replicating adenovirus expressing mda-7/IL-24 (ZD55-IL-24), we showed that enforced expression of mda-7/IL-24 in leukemia cells induced autophagy, which was triggered by the upregulation of Beclin-1. Immunofluorescence and coimmunoprecipitation studies suggested that mda-7/IL-24 protein interacts with Beclin-1. Class III PI3K/Beclin-1 complex was shown involved in the mda-7/IL-24-induced autophagy. Moreover, autophagy inhibition by phosphatidylinositol 3-kinase inhibitor, wortmannin, resulted in a reduced Beclin-1 expression and autophagosome formation associated with significantly enhanced cell death. Importantly, the combination of ZD55-IL-24 with wortmannin elicited a strongly enhanced antileukemia efficacy in established leukemia xenografts. These results suggest that mda-7/IL-24-induced autophagy in leukemia cells may provide survival advantage and mda-7/IL-24 combined with agents that disrupt autophagy is a promising new strategy for the treatment of leukemia.

Differential expression of sphingosine-1-phosphate receptors 1-5 in the developing nervous system

Sphingosine-1-phosphate (S1P) binds to G protein-coupled receptors and can regulate a wide range of cellular functions. In a previous study, we isolated two key enzymes in the S1P pathway that were expressed in migrating neural crest cells. To determine if S1P receptors are present in neural crest cells or peripheral nervous system, we examine the expression patterns of S1P receptors (S1pr1-5) in mouse, and s1pr1 and s1pr3 in chick embryos. Here, we present a comprehensive expression analysis of these receptors using in situ hybridizations, which provide spatiotemporal information. We showed that S1pr2 was expressed in migrating cranial neural crest cells and enteric neurons. S1pr1 was prominently expressed in the neuroepithelium whereas S1pr4 and S1pr5 were in neurons at later stages. On the contrary, S1pr3 was predominantly detected in non-neuronal cells within and surrounding neural structures. We also described novel expression sites for S1P receptors in the developing nervous system.

Monophyletic origin of domestic bactrian camel (Camelus bactrianus) and its evolutionary relationship with the extant wild camel (Camelus bactrianus ferus)

The evolutionary relationship between the domestic bactrian camel and the extant wild two-humped camel and the factual origin of the domestic bactrian camel remain elusive. We determined the sequence of mitochondrial cytb gene from 21 camel samples, including 18 domestic camels (three Camelus bactrianus xinjiang, three Camelus bactrianus sunite, three Camelus bactrianus alashan, three Camelus bactrianus red, three Camelus bactrianus brown and three Camelus bactrianus normal) and three wild camels (Camelus bactrianus ferus). Our phylogenetic analyses revealed that the extant wild two-humped camel may not share a common ancestor with the domestic bactrian camel and they are not the same subspecies at least in their maternal origins. Molecular clock analysis based on complete mitochondrial genome sequences indicated that the sub-speciation of the two lineages had begun in the early Pleistocene, about 0.7 million years ago. According to the archaeological dating of the earliest known two-humped camel domestication (5000-6000 years ago), we could conclude that the extant wild camel is a separate lineage but not the direct progenitor of the domestic bactrian camel. Further phylogenetic analysis suggested that the bactrian camel appeared monophyletic in evolutionary origin and that the domestic bactrian camel could originate from a single wild population. The data presented here show how conservation strategies should be implemented to protect the critically endangered wild camel, as it is the last extant form of the wild tribe Camelina.