Valeria Marini

Mutation Analysis of CCM1, CCM2 and CCM3 Genes in a Cohort of Italian Patients with Cerebral Cavernous Malformation

Cerebral cavernous malformations (CCMs) are vascular lesions of the CNS characterized by abnormally enlarged capillary cavities. CCMs can occur as sporadic or familial autosomal dominant form. Familial cases are associated with mutations in CCM1[K‐Rev interaction trapped 1 (KRIT1)], CCM2 (MGC4607) and CCM3 (PDCD10) genes. In this study, a three‐gene mutation screening was performed by direct exon sequencing, in a cohort of 95 Italian patients either sporadic or familial, as well as on their at‐risk relatives. Sixteen mutations in 16 unrelated CCM patients were identified, nine mutations are novel: c.413T > C; c.601C > T; c.846 + 2T > G; c.1254delA; c.1255‐4delGTA; c.1681‐1682delTA in CCM1; c.48A > G; c.82‐83insAG in CCM2; and c.396G > A in CCM3 genes. The samples, negative to direct exon sequencing, were investigated by MLPA to search for intragenic deletions or duplications. One deletion in CCM1 exon 18 was detected in a sporadic patient. Among familial cases 67% had a mutation in CCM1, 5.5% in CCM2, and 5.5% in CCM3, whereas in the remaining 22% no mutations were detected, suggesting the existence of either undetectable mutations or other CCM genes. This study represents the first extensive research program for a comprehensive molecular screening of the three known genes in an Italian cohort of CCM patients and their at‐risk relatives.

Search for loss of heterozygosity and mutation analysis of KRIT1 gene in CCM patients

Cerebral cavernous malformation (CCM) is a vascular disorder of the brain characterized by dilated capillary-like sinusoid chambers lined by a single layer of endothelium and thin fibrous adventitia but lacking other vessel wall components and intervening neural structures [Clatterbuck et al., 2001]. Spinal, cutaneous, retinal, and vertebral cavernous angiomas have also been observed. Both sporadic and familial forms have been identified. The familial form exhibits autosomal dominant inheritance with variable clinical expression and incomplete penetrance with three known loci on chromosomes 7q21.2 (CCM1), 7p15-p13 (CCM2), and 3q25.2-q27 (CCM3). The first gene identified on CCM1 locus is KRIT1 encoding KREV-1/RAP1 interaction trapped 1 protein (KRIT1), which is responsible for 40% or more of familial cases. Recently a novel gene MGC4607 has been isolated on the CCM2 locus [Liquori et al., 2003]. The KRIT1 gene has been reported to include 16 coding exons [Sahoo et al., 2001]. KRIT1 is a protein of 736 aminoacids and a molecular mass of 81 kDa containing N-terminal ankyrin repeats, one FERM domain, one trans-membrane domain, and a region at the C-terminal interacting with RAP1A [Sahoo et al., 2001; Marini et al., 2003]. The combina-

In vitro and in vivo antiproliferative activity of metformin on stem-like cells isolated from spontaneous canine mammary carcinomas: translational implications for human tumors

BackgroundCancer stem cells (CSCs) are considered the cell subpopulation responsible for breast cancer (BC) initiation, growth, and relapse. CSCs are identified as self-renewing and tumor-initiating cells, conferring resistance to chemo- and radio-therapy to several neoplasias. Nowadays, th (about 10mM)e pharmacological targeting of CSCs is considered an ineludible therapeutic goal. The antidiabetic drug metformin was reported to suppress in vitro and in vivo CSC survival in different tumors and, in particular, in BC preclinical models. However, few studies are available on primary CSC cultures derived from human postsurgical BC samples, likely because of the limited amount of tissue available after surgery. In this context, comparative oncology is acquiring a relevant role in cancer research, allowing the analysis of larger samples from spontaneous pet tumors that represent optimal models for human cancer.MethodsIsolation of primary canine mammary carcinoma (CMC) cells and enrichment in stem-like cell was carried out from fresh tumor specimens by culturing cells in stem-permissive conditions. Phenotypic and functional characterization of CMC-derived stem cells was performed in vitro, by assessment of self-renewal, long-lasting proliferation, marker expression, and drug sensitivity, and in vivo, by tumorigenicity experiments. Corresponding cultures of differentiated CMC cells were used as internal reference. Metformin efficacy on CMC stem cell viability was analyzed both in vitro and in vivo.ResultsWe identified a subpopulation of CMC cells showing human breast CSC features, including expression of specific markers (i.e. CD44, CXCR4), growth as mammospheres, and tumor-initiation in mice. These cells show resistance to doxorubicin but were highly sensitive to metformin in vitro. Finally, in vivo metformin administration significantly impaired CMC growth in NOD-SCID mice, associated with a significant depletion of CSCs.ConclusionsSimilarly to the human counterpart, CMCs contain stem-like subpopulations representing, in a comparative oncology context, a valuable translational model for human BC, and, in particular, to predict the efficacy of antitumor drugs. Moreover, metformin represents a potential CSC-selective drug for BC, as effective (neo-)adjuvant therapy to eradicate CSC in mammary carcinomas of humans and animals.

Identification of a novel KRIT1 mutation in an Italian family with cerebral cavernous malformation by the protein truncation test

Familial cerebral cavernous malformation (CCM) exhibits autosomal dominant inheritance and is characterized by vascular disorders of the brain, which can lead to seizures, focal neurological deficits, hemorrhagic stroke, and migraine. Three CCM loci have been mapped, but the gene for only one locus--KRIT1 coding for Krev-1/rap1 interaction trapped 1 (KRIT1) protein, which is responsible for more than 40% of familial cases--has been identified. To date, a total of 72 mutations have been described, with one founder effect in the Mexican/Hispanic community. We report the case of an Italian family with CCM that has a novel KRIT1 gene mutation leading to a truncated KRIT1 protein. The protein truncation test (PTT) has been used as a rapid method of identifying germline mutations in the KRIT1 gene.

An Italian dominant FALS Leu144Phe SOD1 mutation: Genotype-phenotype correlation

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurological disease. Mutations of the Cu/Zn superoxide dismutase gene (SOD1) are responsible for 20% of autosomal dominant familial ALS (FALS). RESULTS: We examined the clinical features of the first Italian FALS with the Leu144Phe SOD1 mutation. Seven affected members were identified in a six‐generation pedigree. A slowly progressive course (20.4±14.6 years) was observed in five patients. One patient died of cardiac failure two years after the onset of the disease. The propositus is still alive. Neurological manifestations began in the legs in all patients, while bulbar signs were absent or appeared late in the course of the disease. DISCUSSION: There is evidence of a correlation between this mutation and a slowly progressive phenotype of ALS. Moreover this rare mutation might derive from a common ancestor.

Meropenem for treating KPC-producing Klebsiella pneumoniae bloodstream infections: Should we get to the PK/PD root of the paradox?

ABSTRACT The objective of this study was to assess the achievement of pharmacokinetic/pharmacodynamic (PK/PD) targets of meropenem (MEM) in critically-ill patients with bloodstream infections (BSI) due to Klebsiella pneumoniae-carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) with MEM minimum inhibitory concentrations (MICs) ≥16 mg/L. Nineteen critically-ill patients with KPC-Kp BSI were given combination therapy including MEM, tigecycline, plus colistin or gentamicin (according to susceptibility testing). MEM was administered as an extended 3-hour infusion of 2 g every 8 hours, or adjusted according to renal function. MEM plasma concentrations were determined by high-performance liquid chromatography. PK/PD targets for MEM were defined as T > 40% 1×MIC and T > 40% 4×MIC. Possible synergisms between MEM and coadministered agents were assessed by time-kill assays based on plasma levels for MEM and on fixed plasma concentrations for the other agents. In none of 19 patients MEM reached any PK/PD target. The actual MEM MICs were 256, 512, and 1024 mg/L in 1, 3, and 15 isolates, respectively. However, theoretically, the PK/PD target of T > 40% 1×MIC could have been achieved in 95%, 68%, 32% and 0% of the isolates for MIC equal to 8, 16, 32, and 64 mg/L, respectively. No synergisms were observed between MEM and coadministered agents. In conclusion, high-dose MEM failed to reach PK/PD targets in 19 patients with BSI due to KPC-Kp with very high MEM MICs. On a theoretical basis, our results suggest a possible usefulness of MEM against resistant blood isolates with MICs up to 32 mg/L.

Exposure to asbestos: correlation between blood levels of mesothelin and frequency of micronuclei in peripheral blood lymphocytes.

Inhalation of asbestos, a mineral extensively used in a variety of applications, is strongly associated with malignant mesothelioma (MM), a fatal cancer of the pleura. Soluble mesothelin-related peptides (SMRP) are a promising biomarker suggested for the screening of MM in healthy asbestos-exposed subjects. In the present study a comparison of micronucleus (Mn) frequencies in peripheral blood lymphocytes (PBL) between 44 asbestos-exposed and 22 control individuals has been performed, and the correlation with serum SMRP has been examined. SMRP levels were found to be significantly higher in subjects exposed to asbestos and in their various subgroups than in controls. Concerning micronucleated lymphocytes, a statistically significant difference from controls was seen in the percentages of both micronucleated mononucleated lymphocytes (MnMNL) and micronucleated binucleated lymphocytes (MnBNL), but the difference was markedly higher for the percentage of micronucleated polynucleated lymphocytes (MnPNL). With respect to the correlation between the frequency of the three types of micronucleated lymphocytes and serum-SMRP values of asbestos-exposed subjects, it was statistically significant for MnMNL, but not for MnBNL and MnPNL.

Involvement of the mu-opioid receptor gene polymorphism A118G in the efficacy of detoxification of alcohol dependent patients

INTRODUCTION The A118G (rs 1799971) polymorphism in the mu-opioid receptor gene (OPRM1) has been reported to be associated with alcohol addiction. METHODS In this study 109 patients diagnosed with alcohol dependence in accordance with DMS-IV criteria and 95 healthy subjects were enrolled and everyone has been genotyped. RESULTS The percentage of alcoholic patients with higher than normal gamma-glutamyl transferase (GGT) levels significantly decreased after six months of standard detoxification treatment, both in patients with A/A genotype and in the other ones with A/G genotype. However, the percentage of alcohol dependent patients with the A/A genotype recorded a slight decrease of the GGT and the mean corpuscolar volume of erythrocytes (MCV) combination marker after six months of therapy (30% vs 12%), while subjects with the A/G genotype showed no variation. CONCLUSION This finding suggests that alcohol dependent patients with the A/A genotype could have a faster restoration of their liver function than those ones with the A/G genotype: it might be possible that the presence of G allele confers on these patients a reduced ability in abstaining from drinking alcohol.

Determination of deferasirox plasma concentrations: do gender, physical and genetic differences affect chelation efficacy?

Bioavailability of deferasirox (DFX) is significantly affected by the timing of administration relative to times and to composition of meals. Its elimination half‐life is also highly variable – in some patients as a result of gene polymorphisms. Understanding whether deferasirox plasma levels are related to specific characteristics of patients could help physicians to devise a drug regimen tailored the individual patient.

I112M SOD1 mutation causes ALS with rapid progression and reduced penetrance in four Mediterranean families

Abstract We evaluated a possible genotype-phenotype correlation and looked for a founder effect in four Mediterranean families carrying the I112M SOD1 mutation. The structural characteristics of the mutated protein were also analysed. Clinical data of FALS subjects from four families were evaluated. Mutational analysis of the SOD1 gene was carried out by direct sequencing. A haplotype study was carried out using 11 polymorphic markers flanking the SOD1 gene. Structural analysis was performed by means of homology modelling and molecular graphics methods. The clinical pattern of 17 FALS patients was characterized by prevalent spinal onset, mean age at onset of 47.1 years and mean duration of 20.7 months. Several obligate carriers were observed. These findings indicate that the I112M mutation is consistently associated with a uniform, fast-progressing phenotype with reduced penetrance of the disease. The haplotype analysis did not show a common haplotype among the Spanish families and the Italian family; however, a possible common founder could be hypothesized for Spanish families. From a structural viewpoint, mutation at codon 112 seems to confer a severe phenotype, probably related to altered protein functionality.