Bone invasion by oral squamous cell carcinoma.

BACKGROUND: With regards to the anatomical relationships in the mouth, oral squamous cell carcinoma can invade the maxilla or the mandible. According to the TNM system, tumours that invade through cortical bone are classified as T4a, stage IVA. Bone invasion by oral squamous cell carcinoma most often occurs in tumours close to the bone or in larger and more advanced tumours. It is considered an adverse prognostic factor and it is often a diagnostic and therapeutic problem. Destruction of the bone tissue is mediated by activated osteoclasts rather than directly by carcinoma. Tumor necrosis factors - receptor activator of NF-kB (RANK), receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) - play an important role in osteoclastogenesis. According to histological point of view, there are three patterns of bone invasion - erosive, mixed and infiltrative. The most commonly used imaging techniques when evaluating bone invasion by oral squamous cell carcinoma include CT and MRI. PURPOSE: This review is focused on the cellular and molecular mechanisms, histological patterns and detection methods of bone invasion caused by oral squamous cell carcinoma.

Identification of multiple substrates of the StkP Ser/Thr protein kinase in Streptococcus pneumoniae.

Monitoring the external environment and responding to its changes are essential for the survival of all living organisms. The transmission of extracellular signals in prokaryotes is mediated mainly by two-component systems. In addition, genomic analyses have revealed that many bacteria contain eukaryotic-type Ser/Thr protein kinases. The human pathogen Streptococcus pneumoniae encodes 13 two-component systems and has a single copy of a eukaryotic-like Ser/Thr protein kinase gene designated stkP. Previous studies demonstrated the pleiotropic role of the transmembrane protein kinase StkP in pneumococcal physiology. StkP regulates virulence, competence, and stress resistance and plays a role in the regulation of gene expression. To determine the intracellular signaling pathways controlled by StkP, we used a proteomic approach for identification of its substrates. We detected six proteins phosphorylated on threonine by StkP continuously during growth. We identified three new substrates of StkP: the Mn-dependent inorganic pyrophosphatase PpaC, the hypothetical protein spr0334, and the cell division protein DivIVA. Contrary to the results of a previous study, we did not confirm that the alpha-subunit of RNA polymerase is a target of StkP. We showed that StkP activation and substrate recognition depend on the presence of a peptidoglycan-binding domain comprising four extracellular penicillin-binding protein- and Ser/Thr kinase-associated domain (PASTA domain) repeats. We found that StkP is regulated in a growth-dependent manner and likely senses intracellular peptidoglycan subunits present in the cell division septa. In addition, stkP inactivation results in cell division defects. Thus, the data presented here suggest that StkP plays an important role in the regulation of cell division in pneumococcus.

Kinship and Y-chromosome analysis of 7th century human remains: novel DNA extraction and typing procedure for ancient material.

AIM: To develop novel DNA extraction and typing procedure for DNA identification of the 7th century human remains, determine the familiar relationship between the individuals, estimate the Y-chromosome haplogroup, and compare the Y-chromosome haplotype with the contemporary populations. METHODS: DNA from preserved femur samples was extracted using the modified silica-based extraction technique. Polymerase chain reaction amplification was performed using human identification kits MiniFiler, Identifiler, and Y-filer and also laboratory-developed and validated Y-chromosome short tandem repeat (STR) pentaplexes with short amplicons. RESULTS: For 244A, 244B, 244C samples, full autosomal DNA profiles (15 STR markers and Amelogenin) and for 244D, 244E, 244F samples, MiniFiler profiles were produced. Y-chromosome haplotypes consisting of up to 24 STR markers were determined and used to predict the Y-chromosome haplogroups and compare the resulting haplotypes with the current population. Samples 244A, 244B, 244C, and 244D belong to Y-chromosome haplogroup R1b and the samples 244E and 244F to haplogroup G2a. Comparison of ancient haplotypes with the current population yielded numerous close matches with genetic distance below 2. CONCLUSION: Application of forensic genetics in archaeology enables retrieving new types of information and helps in data interpretation. The number of successfully typed autosomal and Y-STR loci from ancient specimens in this study is one of the largest published so far for aged samples.

Characterization of a eukaryotic type serine/threonine protein kinase and protein phosphatase of Streptococcus pneumoniae and identification of kinase substrates.

Searching the genome sequence of Streptococcus pneumoniae revealed the presence of a single Ser/Thr protein kinase gene stkP linked to protein phosphatase phpP. Biochemical studies performed with recombinant StkP suggest that this protein is a functional eukaryotic-type Ser/Thr protein kinase. In vitro kinase assays and Western blots of S. pneumoniae subcellular fractions revealed that StkP is a membrane protein. PhpP is a soluble protein with manganese-dependent phosphatase activity in vitro against a synthetic substrate RRA(pT)VA. Mutations in the invariant aspartate residues implicated in the metal binding completely abolished PhpP activity. Autophosphorylated form of StkP was shown to be a substrate for PhpP. These results suggest that StkP and PhpP could operate as a functional pair in vivo. Analysis of phosphoproteome maps of both wild-type and stkP null mutant strains labeled in vivo and subsequent phosphoprotein identification by peptide mass fingerprinting revealed two possible substrates for StkP. The evidence is presented that StkP can phosphorylate in vitro phosphoglucosamine mutase GlmM which catalyzes the first step in the biosynthetic pathway leading to the formation of UDP-N-acetylglucosamine, an essential common precursor to cell envelope components.

A eukaryotic-type serine/threonine protein kinase StkP of Streptococcus pneumoniae acts as a dimer in vivo.

Streptococcus pneumoniae carries a single Ser/Thr protein kinase gene stkP in its genome. Biochemical studies performed with recombinant StkP have revealed that this protein is a functional membrane-linked eukaryotic-type Ser/Thr protein kinase. Here, we demonstrate that the deletion of its extracellular domain negatively affects the stability of a core kinase domain. In contrast, the membrane anchored kinase domain and the full-length form of StkP were stable and capable of autophosphorylation. Furthermore, evidence is presented that StkP forms dimers through its transmembrane and extracellular domains.

Eukaryotic-type serine/threonine protein kinase StkP is a global regulator of gene expression in Streptococcus pneumoniae.

Signal transduction pathways in both prokaryotes and eukaryotes utilize protein phosphorylation as a key regulatory mechanism. Recent studies have proven that eukaryotic-type serine/threonine protein kinases (Hank's type) are widespread in many bacteria, although little is known regarding the cellular processes they control. In this study, we have attempted to establish the role of a single eukaryotic-type protein kinase, StkP of Streptococcus pneumoniae, in bacterial survival. Our results indicate that the expression of StkP is important for the resistance of S. pneumoniae to various stress conditions. To investigate the impact of StkP on this phenotype, we compared the whole-genome expression profiles of the wild-type and DeltastkP mutant strains by microarray technology. This analysis revealed that StkP positively controls the transcription of a set of genes encoding functions involved in cell wall metabolism, pyrimidine biosynthesis, DNA repair, iron uptake, and oxidative stress response. Despite the reduced transformability of the stkP mutant, we found that the competence regulon was derepressed in the stkP mutant under conditions that normally repress natural competence development. Furthermore, the competence regulon was expressed independently of exogenous competence-stimulating peptide. In summary, our studies show that a eukaryotic-type serine/threonine protein kinase functions as a global regulator of gene expression in S. pneumoniae.