Diacylglycerol lipase alpha promotes tumorigenesis in oral cancer by cell-cycle progression.

Diacylglycerol lipase alpha (DAGLA), which catalyzes the hydrolysis of diacylglycerol to 2-arachidonoylglycerol and free fatty acid, is required for axonal growth during the brain development and for retrograde synaptic signaling at mature synapses. So far, no information was found regarding the possible role of DAGLA in human tumorigenesis. Thus, the current study sought to clarify the contribution of DAGLA in oral squamous cell carcinomas (OSCCs) and assess the clinical possibilities for OSCC treatment. Using real-time quantitative reverse transcription-polymerase chain reaction, immunoblotting, and immunohistochemistry, we found a significant up-regulation of DAGLA in OSCCs compared with normal cells and tissues both at mRNA and protein expression levels. Knockdown models in OSCC-derived cell lines for DAGLA (siDAGLA) and treatment with a lipase inhibitor (orlistat) showed several depressed cellular functions, including cellular proliferation and migratory activities through cell-cycle arrest at G1 phase. Furthermore, we found that DAGLA-positive OSCC samples were correlated highly with the primary tumoral size. We concluded that DAGLA may be a key determinant in tumoral progression and might be a therapeutic target for OSCCs.

A case of mandibular osteomyelitis in a patient with chronic myelomonocytic leukaemia.

We report a case of chronic myelomonocytic leukaemia (CMMoL) in a 68-year-old man who developed osteomyelitis of the mandible. At the initial visit, he reported uncontrolled gingival bleeding, despite self-administered haemostasis. He complained of severe pain in the socket, despite potent opioid analgesia. After consultation with the internal medicine specialists, we undertook a surgical anti-inflammatory approach that included sequestrectomy with massive blood transfusion. His physical condition was ameliorated after the surgical procedure, and he was discharged from the hospital. However, 3 months later, he died because of cardiac arrest after haemorrhagic shock and cardiovascular failure because his CMMoL had developed to an acute blastic crisis. This experience demonstrates that the most important goal in such cases is to alleviate a patient's discomfort by applying minimally invasive actions to eliminate infection and improve the quality of life without causing deterioration in the CMMoL status.

Lipocalin-2 is associated with radioresistance in oral cancer and lung cancer cells.

The aim of the present study was to identify a target molecule that could predict the efficacy of radiotherapy in oral squamous cell carcinoma (OSCC). We used DNA microarray analysis to identify differences in gene expression after X-ray irradiation. We compared the gene expression profiles between X-ray (8 Gy)-irradiated Ca9-22 cells (an OSCC-derived cell line) and unirradiated Ca9-22 cells. A total of 167 genes with a 2-fold higher level of expression induced by X-ray irradiation were identified. Lipocalin-2 (LCN2) had the greatest increase in expression after X-ray irradiation, and it was categorized in a network that has cancer-related functions with the Ingenuity Pathway Analysis tool. Upregulated expression of LCN2 mRNA was validated by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) analysis. When the LCN2 gene was knocked down in OSCC cells (Ca9-22 and HSC-2) and lung cancer cells (A549) by using small interfering RNA, the radiosensitivity of these cells was enhanced. Our findings suggest that the overexpression of LCN2 is likely associated with radioresistance in oral cancer and lung cancer cells, and that LCN2 expression levels could be used to predict radioresistance. Thus, regulating the expression or function of LCN2 could enhance the radiation response, resulting in a favorable outcome of radiotherapy.

Epithelioid myoepithelioma of the hard palate.

BACKGROUND: Myoepithelioma, a generally benign tumor comprised of myoepithelial cells, is an uncommon salivary gland tumor. Among four morphologic variants of myoepithelioma, epithelioid type has not been reported in the oral and maxillofacial region. CASE REPORT: A 61-year-old man first noticed the mass 3 years previously. The oral examination revealed a firm, non-tender, and well-circumscribed mass in the middle of the hard palate. A magnetic resonance imaging scan showed a well-circumscribed mass with low signal intensity (T(1)-weighted image) or increased signal intensity (T(2)-weighted image). DISCUSSION: Immunohistochemically, the tumor cells in the present case reacted to the epithelial (CK HMW and CAM5.2) and the mesenchymal (vimentin) markers. However, myoepithelial markers (S-100 protein, α-smooth muscle actin, glial fibrillary acidic protein, and calponin), except p63, were not expressed in the tumor cells. These results indicated that the epithelial myoepithelioma cells differentiated into epithelial cells rather than myoepithelial cells. We believe that epithelioid myoepithelioma of the palate is a distinctive subtype of myoepithelioma that should be included in the differential diagnosis of tumors of the palate.

Clinical presentation and treatment of distal anterior inferior cerebellar artery aneurysms.

Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals. Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n = 5) followed by the postmeatal (n = 3) and premeatal segment (n = 1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery. We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3 months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75 %). We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.

Primary T-cell/histiocyte-rich B-cell lymphoma arising in the trigeminal ganglion in a patient with rheumatoid arthritis.

We report a cased of a 68-year-old man with primary T-cell/histiocyte-rich B-cell lymphoma (T/HRBCL) that arose in the trigeminal ganglion. He had a 30-year history of rheumatoid arthritis and presented with progressive left facial pain that had started 3 weeks earlier. Magnetic resonance imaging (MRI) revealed an enhanced mass in the trigeminal ganglion and swelling of the distal part of the trigeminal root. The tumor, subtotally resected via the left anterior petrosal approach, was composed of proliferating CD30- and CD79-positive atypical large polygonal cells with hyperchromatic single or multiple nuclei. CD3-positive small lymphoid cells and CD68-positive histiocytic cells were intermingled with the neoplastic cells. These findings were compatible with T/HRBCL. After whole-brain radiation, his facial pain improved and he was discharged. Postoperatively, he developed transient left sixth nerve paresis. This is the first report of this rare type of B-cell lymphoma arising from the trigeminal ganglion. We posit that his prolonged immunosuppressive treatment for rheumatoid arthritis contributed to its development.

Subfrontal schwannoma mimicking neuroblastoma: case report.

Computed tomography (CT), performed in a healthy 28-year-old man after minor head injury, detected a frontal base tumor. Neurological examination revealed left hyposmia. On magnetic resonance imaging scans, there was a heterogeneously enhanced tumor located in the left paramedian frontal base with extension into the left ethmoid sinus. Angiography showed a hypervascular mass in the left anterior cranial fossa; it was mainly fed by the left ethmoidal artery. Positron emission tomography scanning showed moderate accumulation of 11-methylmethionine and low accumulation of 18-fluorodeoxyglucose (FDG) at the tumor site. Bone image CT disclosed compressive, nondestructive deformation of the left frontal base. The preoperative diagnosis was olfactory neuroblastoma or meningioma. The tumor was totally resected via bifrontal craniotomy. The tumor was histologically diagnosed as typical schwannoma; it was positive for S-100 protein. We report a rare subfrontal schwannoma with extension into the nasal cavity that mimicked neuroblastoma. Low FDG accumulation and compressive deformation of the anterior skull base may help in the differential diagnosis of these tumors.

Epithelial cell transforming sequence 2 in human oral cancer.

BACKGROUND: Epithelial cell transforming sequence 2 (ECT2) is a guanine nucleotide exchange factor for Rho family GTPase, which has been implicated in the malignant phenotype of human cancers. Little is known about the effect of a high level of ECT2 in regulating oral cancer cell behavior. In this study, we investigated the involvement of ECT2 in oral squamous cell carcinoma (OSCC). METHODOLOGY/PRINCIPAL FINDINGS: We analyzed ECT2 expression in OSCC-derived cell lines and primary OSCCs compared with matched normal tissue (n = 96) by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry. We then evaluated the correlation between the ECT2 expression status in primary OSCCs and the clinicopathological features. ECT2 expression was significantly up-regulated in OSCCs in vitro and in vivo (p<0.05). Among the clinical variables analyzed, higher ECT2 expression also was associated with the TNM stage grading (p<0.05). When we performed functional analyses of ECT2 in OSCC-derived cells using the shRNA system, the cellular proliferation of the ECT2 knockdown cells decreased significantly compared with the control cells (p<0.05). Cell cycle analysis by flow cytometry showed arrest of cell cycle progression at the G1 phase in the ECT2 knockdown cells. We also found up-regulation of the Cip/Kip family of the cyclin-dependent kinase inhibitors, p21(cip1) and p27(kip1), and down-regulation of cyclin D1, cyclin E, and CDK4. These data suggested that the elevated Cip/Kip family induced inhibition of the cyclin D1-CDK complex activity leading to cell cycle arrest at the G1 phase. CONCLUSIONS/SIGNIFICANCE: Our results proposed for the first time that ECT2 is an indicator of cellular proliferation in OSCCs and that ECT2 might be a potential therapeutic target for the development of new treatments for OSCCs.

Overexpression and altered subcellular localization of autophagy-related 16-like 1 in human oral squamous-cell carcinoma: correlation with lymphovascular invasion and lymph-node metastasis.

Autophagy is a dynamic process of subcellular degradation, which has recently sparked great interest because it is involved in various developmental processes and various diseases including cancer. Autophagy-related 16-like 1 is a component of a large protein complex essential for autophagosome formation. We previously applied proteomic methods to characterize differentially expressed proteins in oral squamous cell carcinoma cells and detected significantly high expression levels of autophagy-related 16-like 1 in oral squamous cell carcinoma-derived cell lines compared to human normal oral keratinocytes. In the current study, to further determine the potential involvement of autophagy-related 16-like 1 in oral squamous cell carcinoma, we evaluated the state of autophagy-related 16-like 1 protein expression in human oral premalignant lesions and primary oral squamous cell carcinomas, and correlated the results with clinicopathologic variables. Autophagy-related 16-like 1 immunoreaction was predominant in a variety of subcellular components of oral squamous cell carcinoma tissues, including the cytoplasm and plasma membrane of malignant cells (45% and 39%, respectively) and peritumoral and intratumoral stroma (52%), whereas all of the components in normal tissues had no or faint autophagy-related 16-like 1 expression. In addition, high stromal expression of autophagy-related 16-like 1 was associated significantly with lymphovascular invasion of tumor cells (P = .037) and positive lymph node status (P = .015). Furthermore, cytoplasmic and plasma membranous autophagy-related 16-like 1 were also expressed in abundance in the oral premalignant lesion cells (74% and 32%, respectively). Our finding suggests that dysregulation of autophagy-related 16-like 1 protein expression is a frequent and early event during oral carcinogenesis and could affect the malignant behavior of oral squamous cell carcinoma cells.

Susceptible genes and molecular pathways related to heavy ion irradiation in oral squamous cell carcinoma cells.

BACKGROUND AND PURPOSE: Heavy ion beams are high linear energy transfer (LET) radiation characterized by a higher relative biologic effectiveness than low LET radiation. The aim of the current study was to determine the difference of gene expression between heavy ion beams and X-rays in oral squamous cell carcinoma (OSCC)-derived cells. MATERIALS AND METHODS: The OSCC cells were irradiated with accelerated carbon or neon ion irradiation or X-rays using three different doses. We sought to identify genes the expression of which is affected by carbon and neon ion irradiation using Affymetrix GeneChip analysis. The identified genes were analyzed using the Ingenuity Pathway Analysis Tool to investigate the functional network and gene ontology. Changes in mRNA expression in the genes were assessed by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). RESULTS: The microarray analysis identified 84 genes that were modulated by carbon and neon ion irradiation at all doses in OSCC cells. Among the genes, three genes (TGFBR2, SMURF2, and BMP7) and two genes (CCND1 and E2F3), respectively, were found to be involved in the transforming growth factor beta-signaling pathway and cell cycle:G1/S checkpoint regulation pathway. The qRT-PCR data from the five genes after heavy ion irradiation were consistent with the microarray data (P < 0.01). CONCLUSION: Our findings should serve as a basis for global characterization of radiation-regulated genes and pathways in heavy ion-irradiated OSCC.

PTEN expression and methylation status in oral squamous cell carcinoma.

PTEN is a tumor suppressor gene located on chromosome10q23.3. In addition to genetic mutations and deletions, the down-regulation of PTEN has been found in various malignant tumors. However, little is known about the profile of PTEN gene in oral carcinomas. In this study, the expression profiles and genetic alterations of PTEN were examined in 113 oral squamous cell carcinoma (OSCC) cases and 9 OSCC-derived cell lines. An immunohistochemical analysis showed statistically significant differences in the immunohistochemical (IHC) scores for PTEN protein in normal tissues and in cancerous regions (P=0.0104), suggesting that PTEN protein expression is down-regulated in OSCC. No significant correlations existed between the down-regulation of PTEN protein expression and the clinicopathological features of the tumor. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a lower PTEN mRNA expression in the 9 OSCC-derived cell lines examined, as compared to the normal oral epithelium cells. However, treatment with a demethylating reagent restored PTEN mRNA expression in 4 cell lines. No genetic mutations were detected in these cell lines by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. The results suggest that epigenetic changes may be related to the down-regulation of PTEN expression. We therefore conclude that PTEN is a crucial molecule in the tumorigenesis of OSCC.

Hyaluronan-mediated motility: a target in oral squamous cell carcinoma.

To characterize cancer-related gene expression changes in oral squamous cell carcinomas (OSCCs), we compared the gene expression profiles in OSCC-derived cell lines with human normal oral keratinocytes (HNOKs). Microarray analysis identified 166 genes that were up-regulated in OSCC-derived cell lines. Gene ontology analysis showed that cancer-related function had the highest significance. Among the genes mapped to the cancer-related network with the highest significance, the receptor for hyaluronan-mediated motility (RHAMM) was evaluated further for mRNA and protein expression in the OSCC cell lines, primary OSCCs. Overexpression of RHAMM protein was observed in all cell lines compared to HNOKs. Immunohistochemical analysis showed highly expressed RHAMM in primary OSCCs, whereas most corresponding normal tissues had no or significant down-regulation of protein immunoreactivity. Real-time quantitative reverse transcriptase-polymerase chain reaction data agreed with the protein expression. Moreover, the RHAMM expression status was correlated with the TNM stage (P<0.001). The results suggested that RHAMM expression may be correlated with tumor aggressiveness and offer clues to the development of new treatments for human OSCCs.

Clinical significance of gelsolin-like actin-capping protein expression in oral carcinogenesis: an immunohistochemical study of premalignant and malignant lesions of the oral cavity.

BACKGROUND: Gelsolin-like actin-capping protein (CapG) is a ubiquitous gelsolin-family actin-modulating protein involved in cell signalling, receptor-mediated membrane ruffling, phagocytosis, and motility. CapG has generated great interest due to its oncogenic function in the control of cell migration or invasion in a variety of cancer cells. We previously applied proteomic methods to characterize differentially expressed proteins in oral squamous-cell carcinoma (OSCC) cells and detected significantly high expression levels of CapG in OSCC-derived cell lines compared to human normal oral keratinocytes. In the current study, to further determine the potential involvement of CapG in OSCC, we evaluated the status of CapG protein and mRNA expression in human oral premalignant lesions (OPLs) and primary OSCCs and correlated the results with clinicopathologic variables. METHODS: Matched normal and tumour tissue sections of 79 human primary OSCCs and 28 OPLs were analyzed for CapG expression by immunohistochemistry (IHC). Correlations between CapG-immunohistochemical staining scores of OSCCs and clinicopathologic features were evaluated by Fisher's exact test. Real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to estimate CapG expression at the mRNA level. RESULTS: In IHC, substantial up-regulation of CapG protein was observed in primary OSCCs (52%) and OPLs (64%), whereas corresponding normal tissues showed consistently weak or absent immunoreactivity of CapG. qRT-PCR data were consistent with the protein expression status. Moreover, CapG expression was correlated with the TNM stage grading of OSCCs. CONCLUSION: Our finding of frequent dysregulated expression of CapG in premalignant and malignant lesions together with an association with an advanced clinical disease stage suggests that CapG could contribute to cancer development and progression and that CapG may have potential as a biomarker and a therapeutic target for OSCC.

Genes and molecular pathways related to radioresistance of oral squamous cell carcinoma cells.

To identify genes associated with radioresistant oral squamous cell carcinoma (OSCC), we compared gene expression signatures between OSCC cell lines exhibiting radioresistance and cells with radiosensitivity after X-ray irradiation in a dose-dependent manner using Affymetrix GeneChip analysis with Human Genome-U133 plus 2.0 GeneChip. The microarray data identified 167 genes that were significantly overexpressed in radioresistant cells after X-ray irradiation. Among the genes identified, 40 were mapped to 3 highly significant genetic networks identified by the Ingenuity Pathway Analysis tool. Gene ontology analysis showed that cancer-related function had the highest significance. The 40 genes included 25 cancer-related genes that formed 1 network and were categorized by function into growth and proliferation, apoptosis, and adhesion. Furthermore, real-time quantitative reverse transcriptase-polymerase chain reaction showed that the mRNA expression levels of the 25 genes were higher in radioresistant cells than in radiosensitive cells in a dose-dependent manner and in a time-dependent manner. Our results suggest that the identified genes help to elucidate the molecular mechanisms of the radioresistance of OSCC and could be radiotherapeutic molecular markers for choosing the appropriate radiotherapy for this disease.