We identify a new enzymatic activity underlying metastasis in breast cancer and describe its susceptibility to therapeutic inhibition. We show that human prune (h-prune), a phosphoesterase DHH family appertaining protein, has a hitherto unrecognized cyclic nucleotide phosphodiesterase activity effectively suppressed by dipyridamole, a phosphodiesterase inhibitor. h-prune physically interacts with nm23-H1, a metastasis suppressor gene. The h-prune PDE activity, suppressed by dipyridamole and enhanced by the interaction with nm23-H1, stimulates cellular motility and metastasis processes. Out of 59 metastatic breast cancer cases analyzed, 22 (37%) were found to overexpress h-prune, evidence that this novel enzymatic activity is involved in promoting cancer metastasis.
Cilia are specialized organelles protruding from the cell surface of almost all mammalian cells. They consist of a basal body, composed of two centrioles, and a protruding body, named the axoneme. Although the basic structure of all cilia is the same, numerous differences emerge in different cell types, suggesting diverse functions. In recent years many studies have elucidated the function of 9+0 primary cilia. The primary cilium acts as an antenna for the cell, and several important pathways such as Hedgehog, Wnt and planar cell polarity (PCP) are transduced through it. Many studies on animal models have revealed that during embryogenesis the primary cilium has an essential role in defining the correct patterning of the body. Cilia are composed of hundreds of proteins and the impairment or dysfunction of one protein alone can cause complete loss of cilia or the formation of abnormal cilia. Mutations in ciliary proteins cause ciliopathies which can affect many organs at different levels of severity and are characterized by a wide spectrum of phenotypes. Ciliary proteins can be mutated in more than one ciliopathy, suggesting an interaction between proteins. To date, little is known about the role of primary cilia in adult life and it is tempting to speculate about their role in the maintenance of adult organs. The state of the art in primary cilia studies reveals a very intricate role. Analysis of cilia-related pathways and of the different clinical phenotypes of ciliopathies helps to shed light on the function of these sophisticated organelles. The aim of this review is to evaluate the recent advances in cilia function and the molecular mechanisms at the basis of their activity. The world of ciliaCilia are dynamic organelles projecting from the cell surface. They consist of a basal body located under the cell surface and of a projecting structure called the axoneme. The basal body is composed of a pair of centrioles embedded in the pericentriolar material (PCM). The ciliary axoneme contains nine microtubule doublets surrounded by a membrane contiguous with the plasma membrane. Cilia are classified on the basis of structure and function. The basic structure of the different types of cilia is similar although their function may be tissue-specific and may change during development, tissue morphogenesis and homeostasis.The traditional classification of cilia into two main classes, motile 9+2 and non-motile 9+0, is insufficient to reflect the complexity of all cilia types. The most recent studies indicate that cilia can be divided into at least four main cilia types: motile 9+2, motile 9+0, non-motile 9+2 and non-motile 9+0. In the 9+2 configuration the axoneme contains a central microtubule pair surrounded by the nine microtubule doublets, which is missing in the 9+0
SUMMARYThe intestinal epithelium is a complex system characterized by massive and continuous cell renewal and differentiation. In this context, cell-type-specific transcription factors are thought to play a crucial role by modulating specific transcription networks and signalling pathways. Hnf1a and b are closely related atypical homeoprotein transcription factors expressed in several epithelia, including the gut. With the use of a conditional inactivation system, we generated mice in which Hnf1b is specifically inactivated in the intestinal epithelium on a wild-type or Hnf1a -/-genetic background. Whereas the inactivation of Hnf1a or Hnf1b alone did not lead to any major intestinal dysfunction, the concomitant inactivation of both genes resulted in a lethal phenotype. Double-mutant animals had defective differentiation and cell fate commitment. The expression levels of markers of all the differentiated cell types, both enterocytes and secretory cells, were affected. In addition, the number of goblet cells was increased, whereas mature Paneth cells were missing. At the molecular level, we show that Hnf1a and b act upstream of the Notch pathway controlling directly the expression of two crucial components: Jag1 and Atoh1. We demonstrate that the double-mutant mice present with a defect in intestinal water absorption and that Hnf1a and b directly control the expression of Slc26a3, a gene whose mutations are associated with chloride diarrhoea in human patients. Our study identifies new direct target genes of the Hnf1 transcription factors and shows that they play crucial roles in both defining cell fate and controlling terminal functions in the gut epithelium. KEY WORDS: Gut epithelium, Hnf1, Commitment, Differentiation, MouseHepatocyte nuclear factor 1a and b control terminal differentiation and cell fate commitment in the gut epithelium
The combination of an increase in the cAMP-phosphodiesterase activity of h-prune and its interaction with nm23-H1 have been shown to be key steps in the induction of cellular motility in breast cancer cells. Here we present the molecular mechanisms of this interaction. The region of the nm23-h-prune interaction lies between S120 and S125 of nm23, where missense mutants show impaired binding; this region has been highly conserved throughout evolution, and can undergo serine phosphorylation by casein kinase I. Thus, the casein kinase I d-e specific inhibitor IC261 impairs the formation of the nm23-hprune complex, which translates 'in vitro' into inhibition of cellular motility in a breast cancer cellular model. A competitive permeable peptide containing the region for phosphorylation by casein kinase I impairs cellular motility to the same extent as IC261. The identification of these two modes of inhibition of formation of the nm23-H1-h-prune protein complex pave the way toward new challenges, including translational studies using IC261 or this competitive peptide 'in vivo' to inhibit cellular motility induced by nm23-H1-h-prune complex formation during progression of breast cancer.
PRUNE, the human homologue of the Drosophila gene, is located in 1q21.3, a region highly ampli®ed in human sarcomas, malignant tumours of mesenchymal origin. Prune protein interacts with the metastasis suppressor nm23-H1, but shows impaired a nity towards the nm23-H1 S120G mutant associated with advanced neuroblastoma. Based on these observations, we previously suggested that prune may act as a negative regulator of nm23-H1 activity. We found ampli®cation of PRUNE in aggressive sarcoma subtypes, such as leiomyosarcomas and malignant ®brous histiocytomas (MFH) as well as in the less malignant liposarcomas. PRUNE ampli®cation was generally accompanied by high mRNA and moderate to high protein levels. The sarcoma samples expressed nm23-H1 mostly at low or moderate levels, whereas mRNA and protein levels were moderate to high in breast carcinomas. For the more aggressive sarcoma subtypes, 9/13 patients with PRUNE ampli®cation developed metastases. A similar situation was observed in all breast carcinomas with ampli®cation of PRUNE. Infection of NIH3T3 cells with a PRUNE recombinant retrovirus increased cell proliferation. Possibly, ampli®-cation and overexpression of PRUNE has the same e ect in the tumours. We suggest that ampli®cation and overexpression of PRUNE could be a mechanism for inhibition of nm23-H1 activity that a ect the development or progression of these tumours. Oncogene (2001) 20, 6881 ± 6890.
A genetic interaction between PRUNE and NM23/NDPK has been postulated in Drosophila melanogaster. Many have focused on Drosophila for the genetic combination between PRUNE "knock down" and AWD/NM23 fly mutants bearing the P97S mutation (K-pn, Killer of PRUNE mutation). We postulated a role for PRUNE-NM23 interactions in vertebrate development, demonstrating a physical interaction between the human PRUNE and NM23-H1 proteins, and partially characterizing their functional significance in cancer progression. Here, we present an initial analysis towards the functional characterization of the PRUNE-NM23 interaction during mammalian embryogenesis. Our working hypothesis is that PRUNE, NM23-H1 and their protein-protein interaction partners have important roles in mammalian brain development and adult brain function. Detailed expression analyses from early mouse brain development to adulthood show significant co-expression of these two genes during embryonic stages of brain development, especially focusing on the cortex, hippocampus, midbrain and cerebellum. We hypothesize that their abnormal expression results in an altered pathway of activation, influencing protein complex formation and its protein partner interactions in early embryogenesis. In the adult brain, their function appears concentrated towards their enzyme activities, wherein biochemical variations can result in brain dysfunction.
To develop a predictive scoring system for ultrasound-detected B3 lesions at ultrasound-guided core needle biopsy (US-CNB). A total of 2724 consecutive US-CNBs performed in our Institution (January 2011 to December 2014) were retrospectively reviewed. Inclusion criteria were as follows: (a) histopathological examination of the entire lesion or (b) availability of radiologic follow-up (FUP) ≥24 months. Patient- and lesion-related variables-patients' age, lesion consistency, lesion size, vascularization, BI-RADS category, and US-CNB result-were analyzed. Positive predictive values (PPVs) for malignancy were calculated correlating US-CNB results with excision histology or FUP. A scoring system for underlying malignancy was developed using risk factors weighting. A total of 102 B3 lesions were included: 27 atypical ductal hyperplasia (26.5%), 5 lobular intraepithelial neoplasia (4.9%), 32 radial scar (31.4%), 37 papillary lesions (36.3%), and 1 fibroepithelial lesion (0.9%). Surgery was performed on 71/102 (69.6%) lesions, and 22/71 were malignant; the remaining 31/102 lesions (30.4%) were unchanged at FUP. The overall PPV for malignancy was 21.6%. Patients' age (odds ratio [OR] = 3.63, P = 0.008), lesion consistency (OR = 5.96, P = 0.001), BI-RADS category (OR = 17.52, P < 0.001), and CNB result (OR = 3.6, P = 0.008) were associated with a higher risk of malignancy underestimation and selected as risk factors in the score definition. Two risk groups were identified: low (0-2 points) and high risk (3-5 points), with significantly different risk of malignancy underestimation (8.0% vs 59.3%, P < 0.001). The proposed score helps to predict the risk of malignancy underestimation and choose the management of B3 lesions at US-CNB.
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