Matrix Gla Protein drives stemness and tumor initiation in ovarian cancer.

Ovarian cancer (OC) displays the highest mortality among gynecological tumors, mainly due to early peritoneal dissemination, the high frequency of tumor relapse following primary debulking, and the development of chemoresistance. All these events are thought to be initiated and sustained by a subpopulation of neoplastic cells, termed ovarian cancer stem cells (OCSC), that are endowed with self-renewing and tumor-initiating properties. This implies that interfering with OCSC function should offer novel therapeutic perspectives to defeat OC progression. To this aim, a better understanding of the molecular and functional makeup of OCSC in clinically relevant model systems is essential. We have profiled the transcriptome of OCSC vs. their bulk cell counterpart from a panel of patient-derived OC cell cultures. This revealed that Matrix Gla Protein (MGP), classically known as a calcification-preventing factor in cartilage and blood vessels, is markedly enriched in OCSC. Functional assays showed that MGP confers several stemness-associated traits to OC cells, including a transcriptional reprogramming. Patient-derived organotypic cultures pointed to the peritoneal microenvironment as a major inducer of MGP expression in OC cells. Furthermore, MGP was found to be necessary and sufficient for tumor initiation in OC mouse models, by shortening tumor latency and increasing dramatically the frequency of tumor-initiating cells. Mechanistically, MGP-driven OC stemness was mediated by the stimulation of Hedgehog signaling, in particular through the induction of the Hedgehog effector GLI1, thus highlighting a novel MGP/Hedgehog pathway axis in OCSC. Finally, MGP expression was found to correlate with poor prognosis in OC patients, and was increased in tumor tissue after chemotherapy, supporting the clinical relevance of our findings. Thus, MGP is a novel driver in OCSC pathophysiology, with a major role in stemness and in tumor initiation.

Prolyl-isomerase Pin1 controls Notch3 protein expression and regulates T-ALL progression.

Deregulated Notch signaling is associated with T-cell Acute Lymphoblastic Leukemia (T-ALL) development and progression. Increasing evidence reveals that Notch pathway has an important role in the invasion ability of tumor cells, including leukemia, although the underlying molecular mechanisms remain mostly unclear. Here, we show that Notch3 is a novel target protein of the prolyl-isomerase Pin1, which is able to regulate Notch3 protein processing and to stabilize the cleaved product, leading to the increased expression of the intracellular domain (N3IC), finally enhancing Notch3-dependent invasiveness properties. We demonstrate that the combined inhibition of Notch3 and Pin1 in the Notch3-overexpressing human leukemic TALL-1 cells reduces their high invasive potential, by decreasing the expression of the matrix metalloprotease MMP9. Consistently, Pin1 depletion in a mouse model of Notch3-induced T-ALL, by reducing N3IC expression and signaling, impairs the expansion/invasiveness of CD4(+)CD8(+) DP cells in peripheral lymphoid and non-lymphoid organs. Notably, in in silico gene expression analysis of human T-ALL samples we observed a significant correlation between Pin1 and Notch3 expression levels, which may further suggest a key role of the newly identified Notch3-Pin1 axis in T-ALL aggressiveness and progression. Thus, combined suppression of Pin1 and Notch3 proteins may be exploited as an additional target therapy for T-ALL.

Numb-dependent integration of pre-TCR and p53 function in T-cell precursor development.

Numb asymmetrically segregates at mitosis to control cell fate choices during development. Numb inheritance specifies progenitor over differentiated cell fates, and, paradoxically, also promotes neuronal differentiation, thus indicating that the role of Numb may change during development. Here we report that Numb nuclear localization is restricted to early thymocyte precursors, whereas timed appearance of pre-T-cell receptor (pre-TCR) and activation of protein kinase Cθ promote phosphorylation-dependent Numb nuclear exclusion. Notably, nuclear localization of Numb in early thymocyte precursors favors p53 nuclear stabilization, whereas pre-TCR-dependent Numb nuclear exclusion promotes the p53 downmodulation essential for further differentiation. Accordingly, the persistence of Numb in the nucleus impairs the differentiation and promotes precursor cell death. This study reveals a novel regulatory mechanism for Numb function based on its nucleus-cytosol shuttling, coupling the different roles of Numb with different stages of T-cell development.

Expression of internalin A and biofilm formation among Listeria monocytogenes clinical isolates.

Internalin A (InlA), a cell wall-bound protein of Listeria monocytogenes, is among the major components involved in the adhesion to and invasion of host cells expressing specific forms of E-cadherin. Some L. monocytogenes strains secrete truncated non-functional forms of InlA. The purpose of this study is to compare the biofilm-forming abilities of L. monocytogenes strains from clinical sources expressing InlA proteins in the different forms. A total of 70 L. monocytogenes strains were examined using SDS-PAGE, Western blot, DNA sequencing, and microtitre plate biofilm formation assays. We found that 8 of the 70 strains expressed truncated InlA, and that this group of strains exhibited significantly enhanced biofilm-forming ability compared to the group expressing full-length InlA. Further experiments showed that: (i) L. monocytogenes biofilms were detached by treatment with protease K; (ii) protein fragments resulting from proteolysis, rather than intact proteins, are responsible for biofilm enhancement, because biofilm formation was impaired by the protease inhibitor alpha2-macroglobulin; (iii) truncated and/or proteolytically cleaved InlA are likely involved in the biofilm enhancement, based on the effects that anti-InlA monoclonal antibodies produced on the biofilm formation of L. monocytogenes strains expressing either truncated or full-length InlA. These data provide a basis for further investigation of the molecular structure and composition of L. monocytogenes biofilms.

A case if infant botulism due to neurotoxigenic Clostridium butyricum type E associated with Clostridium difficile colitis.

Reported here is the sixth case of intestinal toxemia botulism caused by Clostridium butyricum type E in Italy since 1984. In this case, the patient was concomitantly affected with colitis due to Clostridium difficile toxin. A review of previously reported cases revealed that some of these patients may also have had intestinal toxemia botulism associated with Clostridium difficile colitis, based on the reported symptoms. Given that this association has been shown to exist not only in Italy but also in the USA, it is recommended that individuals with intestinal botulism and symptoms of colitis undergo testing for Clostridium difficile and its toxins in fecal samples.

Interactions between novel micro-organisms and intestinal flora.

Microbial strains traditionally used to ferment food have a long history of safe use and are, therefore, considered as generally recognised as safe. Many of these micro-organisms have also functional attributes and are included among probiotics. New species and strains of bacteria with desirable technological and functional properties are constantly being identified; in addition, micro-organisms can be engineered by recently developed biotechnological tools in order to accelerate strain improvement. Although the potentialities of novel micro-organisms with better probiotic and technological properties are promising, it cannot be assumed that they share the safety record of traditional micro-organisms, since they may pose unique challenges for human health. The risk assessment and safety evaluation of novel micro-organisms must focus, primarily, on their potential harmful effects, both direct and indirect, upon host resident intestinal microflora. Genetically modified micro-organisms need further assessment for the complete characterisation of the DNA rearrangement and of the final product, in order to establish the "substantial equivalence" with the parental strain.

Characterization of Listeria monocytogenes strains involved in invasive and noninvasive listeriosis outbreaks by PCR-based fingerprinting techniques.

A total of 32 Listeria monocytogenes strains (16 from a recent outbreak of invasive listeriosis and 16 from two outbreaks of noninvasive listeriosis, all three occurring in Italy) were characterized by PCR-ribotyping, arbitrarily primed PCR (AP-PCR), and the recently developed infrequent-restriction-site PCR (IRS-PCR). The discriminatory ability of the techniques, first evaluated on 29 unrelated L. monocytogenes food isolates using Simpson's index of diversity, was 0.714 for PCR-ribotyping, 0.690 for AP-PCR, and 0.919 for IRS-PCR. IRS-PCR was also more capable of distinguishing among strains from the invasive listeriosis outbreak: three different clusters were identified by IRS-PCR compared to two clusters identified by both PCR-ribotyping and AP-PCR. Within each of the two outbreaks of noninvasive listeriosis, the patterns were practically identical, as demonstrated by all three techniques. Only IRS-PCR succeeded in clearly discriminating the strains related to noninvasive listeriosis from all of the other strains included in this study, including those from the outbreak of invasive listeriosis. This finding may suggest the presence of unique differences in their DNA sequences.

An outbreak in Italy of botulism associated with a dessert made with mascarpone cream cheese.

In the late 1996, an outbreak of botulism affected eight young people (age of patients ranged from 6 to 23 years) in Italy. The onset of the illness was the same for all of these patients: gastrointestinal symptoms (nausea and vomiting) followed by neurologic symptoms. The most common neurologic symptoms were dysphagia, respiratory failure (100%), diplopia (87%), dysarthria, ptosis (75%) and mydriasis (50%). All patients required mechanical ventilation. Botulinum toxin was detected from two of respectively five sera and six stool samples analysed, while spores of Clostridium botulinum type A were recovered from all patient' faeces. The epidemiological investigation led to suspect a commercial cream cheese ('mascarpone') as a source of botulinum toxin: indeed, it had been eaten by all the patients before onset of the symptoms, either alone or as the (uncooked) ingredient of a dessert, 'tiramisù'. Botulinum toxin type A was found in the 'tiramisù' leftover consumed by two patients and in some mascarpone cheese samples collected from the same retail stores where the other patients had previously bought their cheeses. A break in the cold-chain at the retail has likely caused germination of C. botulinum spores contaminating the products, with subsequent production of the toxin. One of the patients died, while the others recovered very slowly. Prompt international alerting and recall of the mascarpone cheese prevented the spread of the outbreak due to the wide range of distribution, demonstrating the importance of a rapid surveillance system. None of the people complaining of symptoms after the public alert resulted positive for botulinum spores and toxin.

Intestinal toxemia botulism in two young people, caused by Clostridium butyricum type E.

Two unconnected cases of type E botulism involving a 19-year-old woman and a 9-year-old child are described. The hospital courses of their illness were similar and included initial acute abdominal pain accompanied by progressive neurological impairment. Both patients were suspected of having appendicitis and underwent laparotomy, during which voluminous Meckel's diverticula were resected. Unusual neurotoxigenic Clostridium butyricum strains that produced botulinum-like toxin type E were isolated from the feces of the patients. These isolates were genotypically and phenotypically identical to other neurotoxigenic C. butyricum strains discovered in Italy in 1985-1986. No cytotoxic activity of the strains that might explain the associated gastrointestinal symptoms was demonstrated. The clinical picture of the illness and the persistence of neurotoxigenic clostridia in the feces of these patients suggested a colonization of the large intestine, with in vivo toxin production. The possibility that Meckel's diverticulum may predispose to intestinal toxemia botulism may warrant further investigation.

Clostridium botulinum spores and toxin in mascarpone cheese and other milk products.

A total of 1,017 mascarpone cheese samples, collected at retail, were analyzed for Clostridium botulinum spores and toxin, aerobic mesophilic spore counts, as well as pH, a(w) (water activity), and Eh (oxidation-reduction potential). In addition 260 samples from other dairy products were also analyzed for spores and botulinum toxin. Experiments were carried out on naturally and artificially contaminated mascarpone to investigate the influence of different temperature conditions on toxin production by C. botulinum. Three hundred and thirty-one samples (32.5%) of mascarpone were positive for botulinal spores, and 7 (0.8%) of the 878 samples produced at the plant involved in an outbreak of foodborne botulism also contained toxin type A. The chemical-physical parameters (pH, a(w), Eh) of all samples were compatible with C. botulinum growth and toxinogenesis. Of the other milk products, 2.7% were positive for C. botulinum spores. Growth and toxin formation occurred in naturally and experimentally contaminated mascarpone samples after 3 and 4 days of incubation at 28 degrees C, respectively.

Classic and emergent forms of botulism: the current status in Italy.

Botulism is a rare, severe, neuroparalytic disease. Four forms of botulism are described in humans: foodborne botulism and the more recently described wound botulism, infant botulism, and infant-like botulism. The two last forms are sometimes grouped un

The detection of a deletion in the type B neurotoxin gene of Clostridium botulinum A(B) strains by a two-step PCR.

Differences between the type B neurotoxin gene sequence of Clostridium botulinum type A(B) and Cl. botulinum type B, including a six nucleotide deletion, were recently proposed as a cause of the lack of expression of this gene in the type A toxigenic strains. A polymerase chain reaction (PCR) based on two sets of primers was designed to investigate the absence of the 6-nucleotide sequence in the apparently unexpressed type B toxin gene of 42 strains of Cl. botulinum type A(B). Thirty-five strains were shown to exhibit a deletion in their type B toxin gene; two strains did not have the deletion and actually produced small amounts of type B toxin when tested by the mouse bioassay. This two-step PCR might be useful for the rapid determination of the presence of the six nucleotide deletion and consequently, whether the type B toxin is likely to be produced.

Transient tonic pupils in botulism type B.

We report a 29-year-old woman who developed unilateral unreactive mydriasis and cycloplegia after 5 days of persistent constipation. During the next hours the patient complained of dry mouth and difficulties in swallowing food; iris and ciliary muscle palsies spread over the second eye. Ocular motility was normal and there were no clinical signs of neuromuscular involvement. Conventional electromyography and evoked muscle action potentials following repetitive nerve stimulation were normal; single-fiber electromyography showed normal jitter and absence of blocking. The diagnosis of botulism was considered as most likely, and the patient was given botulinum antitoxin. The post-treatment course was characterized by bilateral tonic pupillary reaction to near, sectoral iris contractions to light and pupillary constriction to 2 mm in 40 min following topical instillation of 0.1% pilocarpine. Ocular manifestations completely disappeared within 5 weeks. Botulism type B toxin was demonstrated in the pretreatment stool of the patient but not the serum.

Genetic typing of human and food isolates of Listeria monocytogenes from episodes of listeriosis.

Ten clinical and food Listeria monocytogenes strains isolated during the epidemiological investigations of episodes of listeriosis (one outbreak and two sporadic cases) that occurred in northern Italy during 1993-1995 have been examined by DNA macrorestriction pattern analysis obtained by PFGE and RAPD typing, in order to confirm the food vehicle of infections. The same DNA profiles within the isolates from the three episodes were obtained by both techniques. The Apal and Smal PFGE profiles and RAPD patterns with primer OPM-01 confirmed the close relationship between strains from two distinct episodes. However, RAPD analysis with primer UBC-127 distinguished between these L. monocytogenes isolates.

Recovery of a strain of Clostridium botulinum producing both neurotoxin A and neurotoxin B from canned macrobiotic food.

A rare strain of Clostridium botulinum subtype Ab was isolated from a canned macrobiotic food suspected of being linked to a fatal case of food-borne botulism. The strain was recovered and identified by conventional methods modified by the inclusion of a PCR assay (G. Franciosa, J.L. Ferreira, and C.L. Hatheway, J. Clin. Microbiol. 32:1911-1917, 1994). The titers of neurotoxins produced by the strain were evaluated by a mouse bioassay.

Effect of combined lysozyme and lipase treatment on the survival of Listeria monocytogenes.

The effectiveness of polyphosphates or lipases to increase the lytic activity of lysozyme was evaluated both on Listeria monocytogenes suspended in buffer and on growing cultures incubated at different temperatures. At 5 degrees C and 37 degrees C polyphosphates combined with lysozyme did not result in the decrease of the number of non-growing L. monocytogenes cells. At the same incubation conditions, the addition of lipase to lysozyme significantly enhanced the bactericidal activity of lysozyme to an extent determined by pH, NaCl concentration and temperature.

PCR for detection of Clostridium botulinum type C in avian and environmental samples.

A PCR was developed and applied for the detection of Clostridium botulinum type C in 18 avian and environmental samples collected during an outbreak of avian botulism, and the results were compared with those obtained by conventional methodologies based on the mouse bioassay. PCR and mouse bioassay results compared well (100%) after the enrichment of samples, but PCR results directly indicated the presence of this microorganism in six samples, while only one of these contained the type C botulinal neurotoxin before enrichment. The PCR assay was sensitive (limit of detection between 15 and 15 x 10(3) spores per PCR), specific (no amplification products were obtained with other clostridia), and rapid, since sonicated and heated samples provided enough template for amplification without any DNA purification. Eleven isolates of C. botulinum type C were recovered from mallards (Anas platyrhynchos), grey herons (Ardea cinerea), and mud during investigation of this outbreak.

Detection of type A, B, and E botulism neurotoxin genes in Clostridium botulinum and other Clostridium species by PCR: evidence of unexpressed type B toxin genes in type A toxigenic organisms.

We studied the effectiveness of the PCR in detecting the type A, B, and E botulism neurotoxin genes in 209 strains of Clostridium botulinum and 29 strains of other Clostridium spp. All 79 strains that produced type A toxin, 77 strains that produced type B toxin, and 51 organisms that produced type E toxin (46 C. botulinum and 5 C. butyricum) were PCR positive in reactions with primers targeting sequences specific for their respective toxin genes. The PCR for type A toxin was positive for one type B toxin-producing strain that produced a small amount of type A toxin in addition to a large amount of type B toxin. Surprisingly, the type B toxin gene was detected in addition to the type A toxin gene in 43 type A toxin-producing strains, only 1 of which could be shown by bioassay to produce biologically active type B toxin in culture. The type B gene was also detected in two strains of C. subterminale, which were determined to be nontoxigenic by bioassay. While the PCR was sensitive and specific in detecting the neurotoxin genes, the discovery of unexpressed toxin genes indicates that PCR results may not be adequate for establishing type B neurotoxigenicity.