Tyrosine-kinase inhibition results in EGFR clustering at focal adhesions and consequent exocytosis in uPAR down-regulated cells of Head and Neck cancers

<p>Abstract</p> <p>Background</p> <p>Antisense (AS) induced down-regulation of uPAR in ACCS adenoid-cyctic carcinoma cells decreased the cellular adhesion and invasion on various extracellular matrices. Additionally, ACCS-AS cells showed an increased EGFR expression and other behavioral similarities to NA-SCC, a typical highly proliferative but less invasive squamous cell carcinoma (SCC) cell line of the head and neck. ACCS, ACCS-AS and NA-SCC cells were used to elucidate the relationships between uPAR down-regulation and EGFR inhibition.</p> <p>Results</p> <p>Tyrosine kinase inhibitor Gefitinib (IRESSA, ZD 1839) significantly reduced the chemotactic cell migration and adhesion. This was associated with reduced EGFR and ERK activation. In addition, anti-proliferative effect of gefitinib in uPAR down-regulated ACCS-AS was significantly higher than parental ACCS, to levels comparable to gefitinib-sensitive NA-SCC cells. This was evidenced by both reduced dosage and duration of treatment. Furthermore, time-lapse videography showed that treatment with gefitinib was also associated with cell rounding and loss of pseudopodia, mostly in ACCS-AS rather than parental ACCS cells. There were also evidences of formation and exocytosis of vacuole-like structures in ACCS-AS, as well as NA-SCC, but not in parental ACCS cells. Interestingly, immunocytochemistry showed that the exocytotic vacuoles actually contained de-activated EGFR.</p> <p>Conclusion</p> <p>Our results suggested that down-regulation of uPAR affected the fate of EGFR in high EGFR expressing cells. Furthermore, combining the uPAR down-regulation with EGFR inhibition showed a synergistic anti-tumor effect and might provide an alternative method to increase anti-proliferative effect of tyrosine kinase inhibitors with lower doses and duration to reduce their side effects during cancer control.</p

Two-stage Method for the Extraction of a Horizontally Impacted Lower Third Molar

AbstractA modification of the surgical technique for extracting impacted lower third molars is required to decrease the rate of complications including inferior alveolar nerve injury. In this study, a new two-stage extraction method for the horizontally impacted lower third molar was developed. During the first stage, only the crown was removed after separating the impacted tooth at the neck. Thereafter, the root(s) was pulled toward the anterior direction with an elastic band at 130–150 g over a 7-day period. Next, the root(s) was extracted. This method was firstly attempted for 20 horizontally impacted lower third molars, the roots of which had been close to the mandibular canal in panoramic radiographs and were pulled for 20.8 ± 11.5 (n = 20) days. The roots in 17 of 20 cases (85%) were loosened from the sockets and extracted easily without any complications. These outcomes suggest that this two-stage method is useful for the extraction of a horizontally impacted lower third molar in order to decrease the rate of inferior alveolar nerve injury

Primary meningioma of the mandible

SummaryWe reported a case of primary extracranial meningioma in the mandible of a 10 year-old-boy with basal cell nevus syndrome. The tumor had a well-delineated large round shaped radiolucency including an impacted canine in the mandible. Microscopic examination revealed a fibrous tumor composed of uniform spindle-shaped cells and fine collagen bundles. The spindle-shaped cells were arranged in whorls and interconnecting fascicles, and some nuclear pseudoinclusion and psammoma bodies were detected. Immunohistochemically, the tumor cells were stained for epithelial membrane antigen, vimentin and desmoplakin, but not for S-100 protein. No recurrence of the tumor was detected for 4 years

Retrospective Study of Selective Submandibular Neck Dissection versus Radical Neck Dissection for N0 or N1 Necks in Level I Patients with Oral Squamous Cell Carcinoma

Objective. To evaluate the efficacy of selective submandibular neck dissection (SMND) in patients with oral squamous cell carcinoma (OSCC) with or without nodal metastasis. Patients. From a total of 384 patients with untreated OSCC who underwent radical excision, we identified 229 with clinically N0 necks and 68 with clinically N1 necks in level I. Main Outcome Measures. The Kaplan-Meier 5-year regional control and 5-year disease specific survival (DSS) were compared for SMND, radical neck dissection (RND), and modified radical neck dissection (MRND). Results. In clinically node-negative necks, the regional control rates were 85.2% with SMND and 83.3% with MRND (P = 0.89), and 5-year DSS rates were 86.5% and 87.0%, respectively, (P = 0.94). In clinically N1 necks, the regional control rates were 81.3% with SMND and 83.0% with RND (P = 0.72), and the DSS rates were 81.3% and 80.0%, respectively, (P = 0.94). Type of neck dissection was not significantly associated with regional control or DSS on either univariate or multivariate analysis using Cox's proportional hazard model. Conclusions. SMND can be effectively applied in elective and therapeutic management to patients with OSCC that are clinically assessed as N0 or N1 to level I of the neck

Clinical Study Retrospective Study of Selective Submandibular Neck Dissection versus Radical Neck Dissection for N0 or N1 Necks in Level I Patients with Oral Squamous Cell Carcinoma

Objective. To evaluate the efficacy of selective submandibular neck dissection (SMND) in patients with oral squamous cell carcinoma (OSCC) with or without nodal metastasis. Patients. From a total of 384 patients with untreated OSCC who underwent radical excision, we identified 229 with clinically N0 necks and 68 with clinically N1 necks in level I. Main Outcome Measures. The Kaplan-Meier 5-year regional control and 5-year disease specific survival (DSS) were compared for SMND, radical neck dissection (RND), and modified radical neck dissection (MRND). Results. In clinically node-negative necks, the regional control rates were 85.2% with SMND and 83.3% with MRND (P = 0.89), and 5-year DSS rates were 86.5% and 87.0%, respectively, (P = 0.94). In clinically N1 necks, the regional control rates were 81.3% with SMND and 83.0% with RND (P = 0.72), and the DSS rates were 81.3% and 80.0%, respectively, (P = 0.94). Type of neck dissection was not significantly associated with regional control or DSS on either univariate or multivariate analysis using Cox&apos;s proportional hazard model. Conclusions. SMND can be effectively applied in elective and therapeutic management to patients with OSCC that are clinically assessed as N0 or N1 to level I of the neck

RT- PCR confirmed the uPAR down-regulation in ACCS-AS cells and constitutively low uPAR expression in NA-SCC cells

ACCS-AS cells showed marked increase in mRNA expression of EGFR, compared to the parental ACCS cells. Constitutive high expression of EGFR in NA-SCC cells is also shown.<p><b>Copyright information:</b></p><p>Taken from "Tyrosine-kinase inhibition results in EGFR clustering at focal adhesions and consequent exocytosis in uPAR down-regulated cells of Head and Neck cancers"</p><p>http://www.molecular-cancer.com/content/7/1/47</p><p>Molecular Cancer 2008;7():47-47.</p><p>Published online 3 Jun 2008</p><p>PMCID:PMC2464604.</p><p></p

Cells were double-stained with anti-EGFR (green) and anti-phosphorylated EGFR(red)

Immunocytochemistry showed that vacuole-like structure formed in ACCS-AS cells upon gefitinib treatment contained mostly de-activated EGFR. Attached cells were markedly reduced at 6 hours. In ACCS cells, vacuole-like formations were not detected. At 6 hours, the number of attached cells was also reduced. In ACCS cells, there were some evidences of internalization of EGFR to the cytoplasm.<p><b>Copyright information:</b></p><p>Taken from "Tyrosine-kinase inhibition results in EGFR clustering at focal adhesions and consequent exocytosis in uPAR down-regulated cells of Head and Neck cancers"</p><p>http://www.molecular-cancer.com/content/7/1/47</p><p>Molecular Cancer 2008;7():47-47.</p><p>Published online 3 Jun 2008</p><p>PMCID:PMC2464604.</p><p></p

Gefitinib led to reduced spreading and cell rounding which was more obvious in ACCS-AS cells

There was also vacuolar formation observed as early as 10 minutes in ACCS-AS cell lines which continued and affected most of cell population with time. Representative vacuole formations on ACCS-AS cells (red arrowheads) are shown. Time-lapse videography also showed that formed vacuoles were exocytosed (see supplemented data). An example of masses speculated to be already exocytosed vacuole sacs are shown (green arrowheads).<p><b>Copyright information:</b></p><p>Taken from "Tyrosine-kinase inhibition results in EGFR clustering at focal adhesions and consequent exocytosis in uPAR down-regulated cells of Head and Neck cancers"</p><p>http://www.molecular-cancer.com/content/7/1/47</p><p>Molecular Cancer 2008;7():47-47.</p><p>Published online 3 Jun 2008</p><p>PMCID:PMC2464604.</p><p></p