Temporal and dynamic changes in gingival blood flow during progression of ligature-induced periodontitis.

OBJECTIVES: To evaluate temporal changes in gingival blood flow (GBF) during progression of periodontitis in rats using a laser Doppler flowmeter (LDF) approach and to characterize morphological and biochemical features in the periodontium associated with GBF. MATERIALS AND METHODS: Forty-two Wistar rats were divided into a ligature-induced periodontitis group and a control group. To induce periodontitis, ligatures were tied around maxillary first molars bilaterally. GBF was measured in palatal gingiva at pretreatment and following ligature placement after 30 min, 1, 3, 7, 14, 21, and 28 days using LDF with a non-contact probe. Bone loss and gene expression in gingival tissues were assessed using micro-computed tomography (µCT) and quantitative polymerase chain reaction (PCR), respectively. Immunostaining for vascular endothelial growth factor (VEGF) in the maxilla was also histologically evaluated. RESULTS: GBF in the ligature group increased significantly compared with the control group 30 min after ligation. However, on days 3 and 7, GBF decreased in the ligature group. Also, after day 10, there was no difference in GBF between groups. The levels of alveolar bone loss, gene expression (interleukin-6, cluster of differentiation-31, VEGF-A, and lymphatic vessel endothelial hyaluronan receptor-1), and immunostained VEGF-positive vessels correlated well with changes in GBF. CONCLUSION PROGRESSION OF PERIODONTITIS: In rats was associated with a triphasic pattern of GBF, consisting of a short initial increase, followed by a rapid decrease, and then a gradual plateau phase.

Upregulation of Tumor Susceptibility Gene 101 (TSG101) by mechanical stress in podocytes.

Elevated mechanical stress in glomerular hypertension is thought to damage podocytes, the loss of which leads to development of glomerulosclerosis. Applying cDNA array analysis to mechanically stressed podocytes, we have recently identified TSG101 as a stretch-induced candidate gene among others. TSG101, which is part of the ESCRT-I complex, is involved in multivesicular body (MVB) formation. Here we demonstrate that TSG101 mRNA is strongly upregulated in conditionally immortalized mouse podocytes by cyclic mechanical stress. Differentiation of podocytes does not affect TSG101 mRNA levels. TSG101 immunofluorescence is distributed in a vesicular pattern in podocytes, the staining intensity being enhanced by mechanical stress. In DOCA/salt treated rats, a model of glomerular hypertension, glomerular TSG101 mRNA levels are elevated, and an increased number of MVBs is observed by electron microscopy in podocyte processes. Our data demonstrate that mechanical stress upregulates TSG101 in podocytes, suggesting that glomerular hypertension enhances sorting of cell surface proteins and their ligands into the degradative pathway in podocytes.

Promoter motifs required for c-mpl gene expression induced by thrombopoietin in CMK cells.

Thrombopoietin (TPO) and its receptor, c-Mpl, are the central regulators of megakaryocyte development and platelet production and are also crucial to regulate megakaryocytopoiesis. TPO remarkably elevated c-mpl promoter activity, while the protein kinase C (PKC) inhibitors, GF109203, H7 and Calphostin C, clearly reduced the steady level of its promoter activity.  In the present study, motifs crucial for c-mpl promoter activity induced by TPO treatment have been analyzed using a human megakaryoblastic cell line, CMK. Destruction of the -107Sp1 and the -57Sp1 sites in the c-mpl promoter enhancer region resulted in decrease of the promoter activity by 53.1% and 64.4%, respectively, and destruction of -69Ets and -28Ets elements dramatically decreased the promoter activity by 96.4% and 87.8%, respectively, while mutation of -77GATA moderately reduced the activity by 31.4%. The result was in agreement with our previous report that showed the crucial motifs in the c-mpl promoter for the promoter activity induced by PMA-treatment. This indicates that TPO-induced activation of the c-mpl promoter activity is fully modulated by transcription through a PKC-dependent pathway and the two Sp1 and two Ets motifs are crucial for the activation of the c-mpl promoter activity rather than a GATA motif in the c-mpl promoter of CMK cells.

Anatomical study of the zygomaticofacial foramen and zygomatic canals communicating with the zygomaticofacial foramen for zygomatic implant treatment: a cadaver study with micro-computed tomography analysis.

In the present study, anatomical assessment of zygomaticofacial foramina (ZFFs) and zygomatic canals communicating with ZFFs were performed using cadaver micro-computed tomography images. It was suggested that all ZFFs were located above the jugale (Ju)-zygomaxillare (Zm) line, which is the reference line connecting the Ju and Zm, and most were located in the zygomatic body area (ZBA). The anteroposterior position of the ZFF in the ZBA was within a middle to posterior region and was most often located slightly posteriorly in males and closer to the middle of the region in females. The mean distance from the Ju-Zm line to the ZFF in the ZBA was 12.36 mm (standard deviation [SD] 1.52 mm) in males and 11.48 mm (SD 1.61 mm) in females. In zygomatic canals communicating with ZFFs, most zygomatic canals were type I canals, communicating from the zygomaticoorbital foramen and harboring the zygomaticofacial nerve, and the others were type II canals, communicating from the zygomaticotemporal foramen and located near the posterior margin of the frontal process. These results provide useful anatomical information for preventing nerve injury during surgical procedures for zygomatic implant treatment.

Spatiotemporal expression profiles of c-Mpl mRNA in the tooth germ: Comparative expression dynamics of vascularization-related genes.

BACKGROUND: Vascularization is an essential event for both embryonic organ development and tissue repair in adults. During mouse tooth development, endothelial cells migrate into dental papilla during the cap stage, and form blood vessels through angiogenesis. Megakaryocytes and/or platelets, as other hematopoietic cells, express angiogenic molecules and can promote angiogenesis in adult tissues. However, it remains unknown which cells are responsible for attracting and leading blood vessels through the dental papilla during tooth development. METHODS: Here we analyzed the spatiotemporal expression of c-Mpl mRNA in developing molar teeth of fetal mice. Expression patterns were then compared with those of several markers of hematopoietic cells as well as of angiogenic elements including CD41, erythropoietin receptor, CD34, angiopoietin-1 (Ang-1), Tie-2, and vascular endothelial growth factor receptor2 (VEGFR2) through in situ hybridization or immunohistochemistry. RESULTS: Cells expressing c-Mpl mRNA was found in several parts of the developing tooth germ, including the peridental mesenchyme, dental papilla, enamel organ, and dental lamina. This expression occurred in a spatiotemporally controlled fashion. CD41-expressing cells were not detected during tooth development. The spatiotemporal expression pattern of c-Mpl mRNA in the dental papilla was similar to that of Ang-1, which preceded invasion of endothelial cells. Eventually, at the early bell stage, the c-Mpl mRNA signal was detected in morphologically differentiating odontoblasts that accumulated in the periphery of the dental papilla along the inner enamel epithelium layer of the future cusp region. CONCLUSION: During tooth development, several kinds of cells express c-Mpl mRNA in a spatiotemporally controlled fashion, including differentiating odontoblasts. We hypothesize that c-Mpl-expressing cells appearing in the forming dental papilla at the cap stage are odontoblast progenitor cells that migrate to the site of odontoblast differentiation. There they attract vascular endothelial cells into the forming dental papilla and lead cells toward the inner enamel epithelium layer through production of angiogenic molecules (e.g., Ang-1) during migration to the site of differentiation. C-Mpl may regulate apoptosis and/or proliferation of expressing cells in order to execute normal development of the tooth.

Nisin lantibiotic prevents NAFLD liver steatosis and mitochondrial oxidative stress following periodontal disease by abrogating oral, gut and liver dysbiosis.

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

Spatiotemporal distribution analyses of Wnt5a ligand and its receptors Ror2, Frizzled2, and Frizzled5 during tongue muscle development in prenatal mice.

BACKGROUND: The mammalian tongue is a highly specialized muscular organ. The Wnt5a ligand regulates muscle development by mediating the activation of several noncanonical Wnt signaling pathways in a receptor context-dependent fashion. However, there is poor information on the expression and behavior of Wnt5a proteins during muscle development of the embryonic tongue. METHODS: The spatiotemporal distribution profiles of the Wnt5a ligand and its receptors, receptor tyrosine kinase-like orphan receptor 2 (Ror2), Frizzled2 (Fzd2), and Frizzled5 (Fzd5), in the developing tongue muscles of prenatal mice from embryonic day 12.5-18.5 were analyzed using immunofluorescence (IF) double staining of a target protein and desmin, a marker protein of myogenic cells. Immunolabeling images were subjected to digital detection analysis using the WinROOF 2018 version 4.19.0 image processing software when needed. RESULTS: IF signals of the Wnt5a ligand protein and its receptors Ror2 and Fzd2 were detected in developing myoblasts and myotubes of the embryonic tongue, but they were undetectable in mature myofibers equipped with sarcomere structures. Fzd2 expression was specific for desmin-positive developing muscle cells, whereas those of Ror2 and the Wnt5a ligand were widespread and nonselective for desmin-positive cells and that of Fzd5 was predominant in desmin-negative cells of the epithelium and subepithelial mesenchyme. CONCLUSION: Developing muscle cells but not mature myofibers of the mouse embryonic tongue express the Wnt5a ligand and its receptors Ror2 and Fzd2, which may mediate Wnt5a signaling in the development processes of tongue muscle fibers.

Bimodal expression of Wnt5a in the tooth germ: A comparative study using in situ hybridization and immunohistochemistry.

BACKGROUND: During tooth development, Wnt5a, a member of the noncanonical Wnt ligand, is expressed prominently in the dental mesenchyme. However, the spatiotemporal profiles of Wnt5a protein production and distribution in tooth germs are largely unknown, which impairs elucidation of the Wnt5a-mediated regulatory mechanism of tooth development. METHODS: We performed analyzes of the spatiotemporal expression of Wnt5a in embryonic tooth germs (E11.5-E18.5) by using in situ hybridization and immunohistochemistry in parallel. The developmental stages of the embryonic tooth germs were determined by HE staining. In order to compare the spatiotemporal distribution patterns of Wnt5a mRNA-expressing cells and those of Wnt5a protein-expressing cells, serial frontal sections of paraffinized mouse embryo heads were used for the analyzes. When needed, the immunohistochemistry images were subjected to digital detection analysis of Wnt5a immunostaining signal using the WinROOF 2018 Ver. 4.19.0 image processing software program. RESULTS: Throughout the developmental process, cells expressing Wnt5a mRNA were found in various tissues including the dental follicle, dental papilla, inner and outer enamel epithelium, stratum intermediate, and stellate reticulum. However, odontoblasts differentiating and polarizing at E18.5 were the only cells representing an accumulation of Wnt5a protein in the apical region of the odontoblast process. The Wnt5a protein was undetectable in undifferentiated mesenchymal cells as well as any other cells positive for Wnt5a mRNA. CONCLUSION: Differentiating odontoblasts execute Wnt5a expression, the mode of which is distinct from that executed by the other cells constituting tooth germ. Change of the mode of Wnt5a expression begins to take place in the mesenchymal cells by E18.5, starting the elongation of the cytoplasmic process.

Decrease of lysyl hydroxylase 2 activity causes abnormal collagen molecular phenotypes, defective mineralization and compromised mechanical properties of bone.

Lysyl hydroxylase 2 (LH2) is an enzyme that catalyzes the hydroxylation of lysine (Lys) residues in fibrillar collagen telopeptides, a critical post-translational modification for the stability of intermolecular cross-links. Though abnormal LH2 activities have been implicated in various diseases including Bruck syndrome, the molecular basis of the pathologies is still not well understood. Since LH2 null mice die at early embryonic stage, we generated LH2 heterozygous (LH2+/-) mice in which LH2 level is significantly diminished, and characterized collagen and bone phenotypes using femurs. Compared to the wild-type (WT), LH2+/- collagen showed a significant decrease in the ratio of hydroxylysine (Hyl)- to the Lys-aldehyde-derived collagen cross-links without affecting the total number of aldehydes involved in cross-links. Mass spectrometric analysis revealed that, in LH2+/- type I collagen, the extent of hydroxylation of all telopeptidyl Lys residues was significantly decreased. In the helical domain, Lys hydroxylation at the cross-linking sites was either unaffected or slightly lower, but other sites were significantly diminished compared to WT. In LH2+/- femurs, mineral densities of cortical and cancellous bones were significantly decreased and the mechanical properties of cortical bones evaluated by nanoindentation analysis were compromised. When cultured, LH2+/- osteoblasts poorly produced mineralized nodules compared to WT osteoblasts. These data provide insight into the functionality of LH2 in collagen molecular phenotype and its critical role in bone matrix mineralization and mechanical properties.

Analysis of vascular distribution and growth factors in human gingival tissue associated with periodontal probing depth.

SUMMARY: Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelium. Tissue levels of this angiogenesis marker are unknown in human gingival tissue, as is the correlation between vascular growth factors and hypoxia-inducible factor. We examined the expression of VEGF, type III tyrosine kinase receptors (VEGF-R2), platelet-endothelial cell adhesion molecule (CD31) and hypoxia-inducible factor (HIF) mRNA from human gingival tissue of the oral cavity. Tissue samples were from a small quantity of gingival sample biopsy with gingival sulcular depth (GSD) < 2 mm (Group 1), 2 to 4 mm (Group 2), and > 4 mm (Group 3). We found that the levels of VEGF-R2, CD31 and HIF mRNA were higher in the gingival tissue of Group 2 than that of Group 1, and VEGF in the Group 3 was also higher than that of Group 1. The different mRNA levels of these markers may reflect the mRNA levels reflect the vasculature state of gingival tissue based on GSD. VEGF-R2 and HIF also indicate the presence of an elongated blood vessel in the gingival tissue. In the early stage of angiogenesis, VEGF-R2 leads to expression of VEGF, and HIF-1 mediates increased VEGF expression in response to hypoxia in swollen tissues or during the expansion of periodontal tissues, which is useful in the early diagnosis of periodontal diseases.

A morphological study of the blood vessels associated with periodontal probing depth in human gingival tissue.

Gingival tissues in human cadavers were examined the blood vessel diameter in the depths of the gingival pockets such as three groups: gingiva adjacent to a sulcus of 2 mm (Group 1); gingiva adjacent to a 2-4-mm sulcus (Group 2); and gingiva adjacent to a sulcus of > 4 mm (Group 3). A meaningful significant difference was seen observed in gingival pocket side, intermediate and outer layer side regions of the gingiva. A meaningful significant difference was seen found in intermediate part and the outer layer of the gingiva in Group 3. Other gingival biopsies were performed on a human body donation specimen to examine CD-31 positive endothelial cells of blood vessels by an immnohistochemical method. Our results suggest that the periodontal probing depth reflect the blood vessel organization of human gingival tissue.

Understanding the formation of maxillary sinus in Japanese human foetuses using cone beam CT.

The formation of the maxillary sinus (MS) is tied to the maturation of the craniofacial bones during development. The MS and surrounding bone matrices in Japanese foetal specimens were inspected using cone beam computed tomography relative to the nasal cavity (NC) and the surrounding bones, including the palatine bone, maxillary process, inferior nasal concha and lacrimal bone. The human foetuses analysed were 223.2 ± 25.9 mm in crown-rump length (CRL) and ranged in estimated age from 20 to 30 weeks of gestation. The amount of bone in the maxilla surrounding the MS increased gradually between 20 and 30 weeks of gestation. Various calcified structures that formed the bone matrix were found in the cortical bone of the maxilla, and these calcified structures specifically surrounded the deciduous tooth germs. By 30 weeks of gestation, the uncinate process of the ethmoid bone formed a border with the maxilla. The distance from the midline to the maximum lateral surface border of the MS combined with the width from the midline to the maximum lateral surface border of the inferior nasal concha showed a high positive correlation with CRL in Japanese foetuses. There appears to be a complex correlation between the MS and NC formation during development in the Japanese foetus. Examination of the surrounding bone indicated that MS formation influences maturation of the maxilla and the uncinate process of the ethmoid bone during craniofacial bone development.

PKC plays a crucial roles in c-mpl gene expression in megakaryoblastic cells.

Thrombopoietin is the cytokine involved in megakaryopoiesis and its receptor (c-Mpl) is considered to regulate development of megakaryocyte. In this research, to elucidate the underlying mechanisms of c-mpl gene expression in megakaryoblastic cells, we investigated the effect of a protein kinase C (PKC) on c-mpl promoter activity in a time-dependent manner. PKC is a member of a family of serine/threonine protein kinases in the cytosol involved in cell growth and differentiation. Phorbol 12-myristate 13-acetate (PMA) is known as PKC activator, significantly enhanced the c-mpl promoter activity and PKC inhibitor, 2-methylpiperazine dihydrochloride (H-7) suppressed the up-regulation of PMA-induced promoter activity and this effect decreased in a time-dependent manner. These results clearly suggest that in megakaryoblastic cells, PKC plays the crucial role in the initiation of up-regulation of PMA-induced c-mpl promoter activity.

Observing the bony canal structure of the human maxillary sinus in Japanese cadavers using cone beam CT.

We observed the location of the posterior superior alveolar artery (PSAA) and nerve at the macroscopic level between the maxillary sinus (MS) and surrounding bone of the anterior region of the maxilla. This study was completed using cone beam computed tomography (CBCT) imaging of 19 human cadavers with 38 sides of Japanese origin (ranging in age from 59-94 years, mean 77.7 +/- 9.8 years) that were prepared for this study. The bony canal structure of the inner surface of the maxilla was clearly apparent in our results, and the bony canals were classified into three types according to the structure along the course of the PSAA: canal-like, ditch-shaped tunnel and fragmented, and the lest sides were undefined. Calcitonin gene-related peptide (CGRP)-positive fibers were identified along the PSAA in the bony canal of the maxilla by immunohistochemistry. The presence of the bony structure and CGRP-positive nerve fibers along the PSAA suggests that there is risk to the PSAA during surgery involving graft implant in the floor of the maxillary sinus.

Evaluation of the blood and nerve supply patterns in the molar region of the maxillary sinus in Japanese cadavers.

The maxillary sinus (MS) in the maxilla bone is located near the orbit, the nasal cavity and the oral cavity; however, the positioning of the constituent bones is complex. The posterior superior alveolar branches of the maxillary artery and nerve are distributed in the lateral wall of the MS. The courses of these blood vessels and nerves are restricted by the morphology of the craniofacial bones, and the landmarks used in dental implant treatment of these courses mainly run along the lateral wall of the MS. In this study, 19 human cadavers with 34 sides of Japanese origin (ranging in age from 59-94 years, mean 77.7 +/- 9.8 years) were prepared for measurement of the MS, the superior alveolar artery and the infraorbital artery using cone beam computed tomography (CBCT). The posterior superior alveolar artery (PSAA) of the lateral wall of the MS can be classified into one of three groups based on the supply pattern. In the greatest number of cadavers, the PSAA ran mainly to the lateral surface of the zone between the superior border of the alveolar foramen and the inferior border of the MS (53.0%, 18/34). In others, the PSAA ran to the zone between the infraorbital foramen and the superior border of the alveolar foramen (17.6%, 6/34); in a third group, the PSAA ran to the zone between the inferior border of the MS and the greater palatine foramen (23.5%, 8/34). The lest of two sides are spread out in this area (5.9%, 2/34). CBCT is the most accurate tool to evaluate important anatomical parameters, such as the distance of the blood supply, for the implant of grafts in the floor of the MS during surgical procedures.

Distribution of glutamate receptor, ionotropic, kainate 1 and neuropeptide calcitonin gene-related peptide mRNAs during formation of the embryonic and postnatal mouse molar in the maxilla.

The neuropeptide calcitonin gene-related peptide (CGRP) is a well-characterized neurotransmitter. Glutamate receptor, ionotropic, kainate 1 (Grik1) has also been demonstrated to generate high-affinity kainate receptors. However, little is known about the roles of CGRP and Grik1 during the developmental formation of teeth. In this study, we endeavoured to analyse the expression and localization of CGRP and Grik1 mRNAs using in situ hybridization on the mouse maxilla during development from the embryonic stage (E18.5) to after birth (P10, P15 and P20). We found that hybridization with an anti-sense probe for CGRP clearly localized in the maxilla at E18.5 in contrast to that of P15 and P20. Hybridization with an anti-sense probe for CGRP was not detected in the dental pulp of molars in the maxilla at P10, which is in contrast to Grik1 mRNA at the same developmental stage. Hybridization with an anti-sense probe for Grik1 mRNA was detected in the basal region of the dental pulp of molars at P10 and P15. Finally, these markers were not detected in molars in the mouse maxilla at P20. The ratio of positive cells for the hybridization signals of Grik1and CGRP in the dental pulp decreased from E18.5 (p<0.001). These features in CGRP and Grik1r mRNAs may indicate roles of function during tooth development between embryonic and postnatal stages with root formation and erupted movements.

Expression of myosin heavy chain isoforms in the postnatal mouse masseter muscle.

We investigated the properties of the masseter muscle in mice from five to seven weeks of age. Myosin heavy chain (MyHC) isoforms were measured in the masseter muscle. The three types of muscle fibers (Type I, strong reaction; Type IIA, intermediate reaction; and Type IIB, weak reaction) were all present in the masseter muscle in five-weeks-old mice and seven-weeks-old mice, the three types could be clearly distinguished by their enzyme activity. The percentage of Type IIB fibers (above 50%) was the highest among all fiber types both 5- and 7-weeks-old mice. The mRNA levels for myosin slow and myosin IIb increased significantly between 5 and 7 weeks. These observations suggest that muscle fiber size, muscle fiber types and mRNA levels of the MyHC isoforms all contribute to the diminished functional adaptability of enzyme activity in the masseter muscle.

Modulation mechanism of c-Mpl promoter activity in megakaryoblastic cells.

Thrombopoietin receptor (c-Mpl) is considered to regulate megakaryocytopoiesis. In this study, we investigated an effect of activation of a protein kinase C (PKC) on c-mpl promoter activity to elucidate the underlying mechanisms of c-mpl gene expression in megakaryoblastic cells. PKC is a member of a family of serine/threonine protein kinases in the cytosol involved in cell growth and differentiation. Phorbol 12-myristate 13-acetate (PMA) is known as PKC activator, significantly enhanced the c-mpl promoter activity and PKC inhibitors (H7, GF109203) suppressed the up-regulation of PMA-induced promoter activity and reduced the steady level of its activity. These results strongly suggest that PKC plays the essential role in the modulation of c-mpl promoter activity of megakaryoblastic cells.

Resveratrol Targets Urokinase-Type Plasminogen Activator Receptor Expression to Overcome Cetuximab-Resistance in Oral Squamous Cell Carcinoma.

Drug resistance to anti-cancer agents is a major concern regarding the successful treatment of malignant tumors. Recent studies have suggested that acquired resistance to anti-epidermal growth factor receptor (EGFR) therapies such as cetuximab are in part caused by genetic alterations in patients with oral squamous cell carcinoma (OSCC). However, the molecular mechanisms employed by other complementary pathways that govern resistance remain unclear. In the current study, we performed gene expression profiling combined with extensive molecular validation to explore alternative mechanisms driving cetuximab-resistance in OSCC cells. Among the genes identified, we discovered that a urokinase-type plasminogen activator receptor (uPAR)/integrin ß1/Src/FAK signal circuit converges to regulate ERK1/2 phosphorylation and this pathway drives cetuximab-resistance in the absence of EGFR overexpression or acquired EGFR activating mutations. Notably, the polyphenolic phytoalexin resveratrol, inhibited uPAR expression and consequently the signaling molecules ERK1/2 downstream of EGFR thus revealing additive effects on promoting OSCC cetuximab-sensitivity in vitro and in vivo. The current findings indicate that uPAR expression plays a critical role in acquired cetuximab resistance of OSCC and that combination therapy with resveratrol may provide an attractive means for treating these patients.

Immunocytochemical localization of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 of the human deciduous molar tooth germ development in the human fetus.

Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelial development. We used immunohistochemical methods to demonstrate the localization of VEGF and its receptors, showing the specific expression pattern of VEGF and VEGF receptor in the human deciduous tooth from the cap to late bell stages in the human fetus. Immunoreactivity to VEGF and its receptor VEGF receptor-2 (VEGFR-2) was intensely positive in the inner enamel epithelium at the cap stage and ranged from negative to moderately positive in the bell stage. At the late bell stage, VEGF immunoreactivity was mainly positive but weak for VEGFR-2. The intensity of VEGF and VEGFR-2 in odontoblasts increases from cap stage to late bell stage. We postulate that the dissimilar expression of VEGF in inner enamel epithelium, ameloblast and odontoblast during each stage of human tooth development may affect tooth germ formation.