Francesca Francioso

Zirconium oxide: analysis of MG63 osteoblast-like cell response by means of a microarray technology.

Zirconium oxide ceramics have outstanding mechanical properties, a high biocompatibility and a high resistance to scratching. Expression profiling by DNA microarray is a molecular technology that allows the analysis of gene expression in a cell system. By using DNA microarrays containing 19,200 genes, we identified in osteoblast-like cells line (MG-63) cultured on zirconium oxide discs (Cercon, Degussa Dental, Hanau, Germany) several genes whose expression was significantly up or down-regulated. The differentially expressed genes cover a broad range of functional activities: (a) immunity, (b) vesicular transport and (c) cell cycle regulation. It was also possible to detect some genes whose function is unknown. The data reported are, to our knowledge, the first genetic portrait of a zirconium oxide surface. They can be relevant to better understand the molecular mechanism of biocompatibility and as a model for comparing other materials.

Analysis of osteoblast-like MG63 cells' response to a rough implant surface by means of DNA microarray.

Several features of the implant surface, such as composition, topography, roughness, and energy, play a relevant role in implant integration with bone. Little is known about the structural and chemical surface properties that may influence biological responses. Expression profiling by DNA microarray is a molecular technology that allows the analysis of gene expression in a cell system. By using DNA microarrays containing 19200 genes, we identified several genes whose expression was significantly down-regulated in osteoblast-like cell line MG63 on a new implant surface (titanium pull spray superficial [TPSS] surface, Oralplant, Cordenons, PN, Italy). The differentially expressed genes cover a broad range of functional activities: (1) signaling transduction, (2) translation, (3) cell cycle regulation, (4) structural and metabolic functions, and (5) apoptosis. It was also possible to detect some genes whose functions are unknown. The data reported can be relevant to better understand the role of the type of surface on the molecular mechanism of implant osseointegration and as a model for comparing other materials.

Linkage analysis of three candidate regions of chromosome 1 in nonsyndromic familial orofacial cleft

Linkage analysis and mouse model knockout studies indicate that loci/genes mapping in different chromosome 1 regions are good candidates for nonsyndromic orofacial cleft (OFC) malformation. On this basis, three different regions of the chromosome 1 have been analysed, by linkage analysis, in 38 families with nonsyndromic OFC. Positive scores were obtained by pairwise analysis and a non-parametric linkage approach for the 1p36 region, with markers close to the MTHFR locus. Additional results allowed us to exclude the presence of an OFC susceptibility gene in the 1q21 and 1q32-42.3 regions.

Genetic Expression Profiling of Six Odontogenic Tumors

Odontogenic tumors are rare neoplasms arising from the odontogenic apparatus. We aimed to identify molecular characteristics associated with odontogenic tumorigenesis and malignancy. To this end, we investigated the expression level of human genes by using, for the first time in odontogenic tumors, the technique of expression profiling. Gene expression alterations common to all six odontogenic tumors were identified by the use of cDNA microarrays containing 19,000 human cDNAs. Statistical analysis on a subset of 4974 cDNAs present in the biopsies identified 506 distinct genes associated with the tumors (p-value < 0.01). Gene ontology analysis of the cellular processes which were differentially regulated in odontogenic tumors was accomplished by the use of a subset of 1409 annotated genes. Finally, 43 cDNAs differentiated the three malignant odontogenic tumors (ameloblastic carcinoma, clear cell odontogenic tumor, granular cell odontogenic tumor) from the three benign ameloblastoma biopsies (p < 0.01). The identified genes might help us better classify borderline odontogenic tumors.

Genetic portrait of malignant granular cell odontogenic tumour

Odontogenic tumours are rare neoplasms whose classification is sometime controversial. Among these entities, granular cell odontogenic tumour (GCOT) is extremely rare and usually has a benign clinical behaviour. While the histogenesis of GCOT remains to be clarified, we documented the existence of a malignant counterpart of this neoplasm and proposed the name of malignant GCOT. Expression profiling by cDNA microarrays is a molecular technology that enables a global gene expression analysis. By using cDNA microarrays, we identified in malignant GCOT several genes with significantly differentially regulated genes when compared to non neoplastic tissues. These cancer specific genes include a range of functional activities: (1) transcription, (2) signaling transduction, (3) cell-cycle regulation, (4) apoptosis, (5) differentiation and (6) angiogenesis. In conclusion, we show that cDNA microarrays is a useful approach to investigate the biology of tumours. Moreover, this technology might lead to identification of gene targets for cancer therapy and to molecular classification of odontogenic tumours.

RNA expression induced by cisplatin in an organ of Corti-derived immortalized cell line

Cisplatin [cis-diamminedichloroplatinum(II)] (CDDP) is an organic compound that is widely used for the treatment of a large number of tumors. Its clinical use is limited by the presence of some undesired side effects, like as oto- and nephro toxicity, whose mechanisms of action are not understood. One of the possible CDDP toxicity mechanism seems to involve the generation of reactive oxygen species (ROS), that can impair morphology and function of hair cells (HC) in the organ of Corti. To test this hypothesis we evaluated the effect of CDDP treatment on RNA steady-state levels of 15,000 genes by microarray analysis, using, as a experimental model, the OC-k3 cell line, obtained from the organ of Corti of transgenic mice and constitutively expressing the large SV40 T antigen. We have found overexpression of several genes related to arachidonate mobilization including phospholipase A2, group IV and V, phospholipase A2 activating protein and lysophospholipase I and III, as well as lipoxygenation like arachidonate 12-lipoxygenase and arachidonate 5-lipoxygenase activating protein. In addition, we found significant transcription of genes regulating cell respiration, including cyt c oxidase, as well as genes involved in xenobiotic detoxification and lipid peroxidation such as cyt P450, and other oxidases including spermine oxidase and monoamine oxidase. As a whole, overexpression of the group of different genes seems to indicate that an oxidative burst could take place during cisplatin administration. We therefore searched for evidences of superoxide anion and hydrogen peroxide by means of electron paramagnetic resonance (EPR) spectroscopy and flow cytometry, but failed to detect them. On the other hand, we found an increase of malondialdehyde (MDA) synthesis and protein carbonylation products, indicating the occurence of lipid peroxidative degradation. When we tested the effectiveness of butylated hydroxytoluene (BHT), dithiothreitol (DTT) and N-acetylcysteine (N-Ac) as cytoprotectants, all of them reduced protein carbonylation to control levels and significantly protected OC-k3 from CDDP-induced cell death, with an higher protection when using the lipophylic antioxidant BHT. The same antioxidants prevented also the onset of protein carbonylation, which extent was decreased to basal levels. These data indicate that CDDP is able to stimulate gene expression up to 12 h after the beginning of the treatment. This increase in gene transcription involves a large number of genes potentially able to increase the level of cell ROS. Consistently, cells survival is improved by cotreatment with antioxidants, in particular lipophilics.

Genetic profile of clear cell odontogenic carcinoma.

In the head and neck region, clear cell tumors are usually derived from salivary glands, odontogenic tissues, and metastasis. The World Health Organization has classified clear cell odontogenic tumor among benign tumors, but it is now recognized as a more sinister lesion, and current opinion is that it should be designated as a carcinoma. It is characterized by aggressive growth, recurrences, and metastasis. By using complementary DNA microarrays, several genes in clear cell odontogenic tumor were identified that are differentially regulated when compared with non-tumor tissue. In conclusion, the first genetic profiling of clear odontogenic carcinoma is reported. DNA microarrays can potentially help in identifying some genes whose products could be disease-specific targets for cancer therapy as well as a tool for better classifying odontogenic tumor.

Correlation of Expression Between Different IMAGE Clones from the Same UniGene Cluster

Through the use of DNA microarray it is now possible to obtain quantitative measurements of the expression of thousands of genes present in a biological sample. DNA arrays yield a global view of gene expression and they can be used in a number of interesting ways. In this paper we are investigating an approach for studying the correlations between different clones from the same UniGene cluster. We will explore all possible couples of clones valuing the linear relations between the expression of these sequences. In this way, we can obtain several results: for example we can estimate measurement errors, or we can highlight genetic mutations. The experiments were done using a real dataset, build from 161 microarray experiments about Hepatocellular Carcinoma.