Role of phosphodiesterase 2 in growth and invasion of human malignant melanoma cells.

Cyclic nucleotide phosphodiesterases (PDEs) regulate the intracellular concentrations and effects of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP). The role of PDEs in malignant tumor cells is still uncertain. The role of PDEs, especially PDE2, in human malignant melanoma PMP cell line was examined in this study. In PMP cells, 8-bromo-cAMP, a cAMP analog, inhibited cell growth and invasion. However, 8-bromo-cGMP, a cGMP analog, had little or no effect. PDE2 and PDE4, but not PDE3, were expressed in PMP cells. Growth and invasion of PMP cells were inhibited by erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA), a specific PDE2 inhibitor, but not by rolipram, a specific PDE4 inhibitor. Moreover, cell growth and invasion were inhibited by transfection of small interfering RNAs (siRNAs) specific for PDE2A and a catalytically-dead mutant of PDE2A. After treating cells with EHNA or rolipram, intracellular cAMP concentrations were increased. Growth and invasion were stimulated by PKA14-22, a PKA inhibitor, and inhibited by N(6)-benzoyl-c AMP, a PKA specific cAMP analog, whereas 8-(4-chlorophenylthio)-2'-O-methyl-cAMP, an Epac specific cAMP analog, did not. Invasion, but not growth, was stimulated by A-kinase anchor protein (AKAP) St-Ht31 inhibitory peptide. Based on these results, PDE2 appears to play an important role in growth and invasion of the human malignant melanoma PMP cell line. Selectively suppressing PDE2 might possibly inhibit growth and invasion of other malignant tumor cell lines.

A Case of Old Calcifying Epithelioma Processed Symptomless over 40 Years.

Calcifying epithelioma, a benign tumor derived from the hair apparatus and consisted of hair matrix cells, is relatively prevalent in females. We report a case of right preauricular calcifying epithelioma that was incidentally detected at the examination of multiple facial fractures and became an old lesion without symptoms for 40 years. The patient who was a 42-year-old male visited our department for the first time in October 2011 with a chief complaint of multiple facial fractures. Radiographic imaging demonstrated fracture lines at the anterior and posterior walls of the left maxillary sinus and zygomatic arch and revealed a mass at a right preauricular area. The extraction was performed under general anaesthesia. No recurrence has been observed 15 months after surgery. We also reviewed the literature of calcifying epithelioma.

Mandibular ameloblastoma in an elderly patient: a case report.

Ameloblastomas frequently occur in relatively young people, but are rarely seen in people aged 80 years or older. We report a case of mandibular ameloblastoma in an elderly patient with a review of the literature. The patient was a 82-year-old man who noticed swelling of the gingiva approximately 2 weeks prior to his initial visit. Computed tomography showed a radiolucent area with little radiopacity. Internal uniformity was observed at the site, with thinning of cortical bone which lacked continuity in some areas. The excision and curettage were performed under general anaesthesia. No recurrence has been observed 14 months after surgery.

Characterization of phosphodiesterase 2A in human malignant melanoma PMP cells.

The prognosis for malignant melanoma is poor; therefore, new diagnostic methods and treatment strategies are urgently needed. Phosphodiesterase 2 (PDE2) is one of 21 phosphodiesterases, which are divided into 11 families (PDE1-PDE11). PDE2 hydrolyzes cyclic AMP (cAMP) and cyclic GMP (cGMP), and its binding to cGMP enhances the hydrolysis of cAMP. We previously reported the expression of PDE1, PDE3 and PDE5 in human malignant melanoma cells. However, the expression of PDE2 in these cells has not been investigated. Herein, we examined the expression of PDE2A and its role in human oral malignant melanoma PMP cells. Sequencing of RT-PCR products revealed that PDE2A2 was the only variant expressed in PMP cells. Four point mutations were detected; one missense mutation at nucleotide position 734 (from C to T) resulted in the substitution of threonine with isoleucine at amino acid position 214. The other three were silent mutations. An in vitro migration assay and a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay revealed that suppressing PDE2 activity with its specific inhibitor, erythro-9-(2-hydroxy-3-nonyl)-adenine (EHNA), had no impact on cell motility or apoptosis. Furthermore, the cytotoxicity of EHNA, assessed using a trypan blue exclusion assay, was negligible. On the other hand, assessment of cell proliferation by BrdU incorporation and cell cycle analysis by flow cytometry revealed that EHNA treatment inhibited DNA synthesis and increased the percentage of G2/M-arrested cells. Furthermore, cyclin A mRNA expression was downregulated, while cyclin E mRNA expression was upregulated in EHNA-treated cells. Our results demonstrated that the PDE2A2 variant carrying point mutations is expressed in PMP cells and may affect cell cycle progression by modulating cyclin A expression. Thus, PDE2A2 is a possible new molecular target for the treatment of malignant melanoma.

A case of carcinoma ex pleomorphic adenoma in the buccal mucosa: review of the literature.

We present a case of carcinoma ex pleomorphic adenoma on the right buccal mucosa in a 52-year-old Japanese woman. Based on the histopathology, the excised tumor was the non-invasive type, but the majority of the tumor consisted of poorly-differentiated adenocarcinoma cells. We performed proton radiation after the surgery. The patient was well, without evidence of disease, 48 months after surgery. Carcinoma ex pleomorphic adenoma in the buccal mucosa has been reported in only four cases during the past twenty years. Therefore, our case was comparatively rare.

A case of congenital granular cell epulis in the maxillary anterior ridge: a study of cell proliferation using immunohistological staining.

Congenital granular cell epulis (CGCE) is a very rare benign tumor that preferentially develops in female infants. The histopathological characteristics of CGCE are very similar to a granular cell tumor, but the histological genesis is unknown. We report a case of a four-day-old female neonate who had a tumor mass in the region of the left maxillary anterior teeth. The rate of cell proliferation was determined by immunostaining with Ki-67 and PCNA, which showed labeling indexes of 16.7 and 15.1%, respectively.

Hyperthermia enhances the antitumor effect of photodynamic therapy with ALA hexyl ester in a squamous cell carcinoma tumor model.

BACKGROUND: Photodynamic therapy (PDT) using 5-aminolevulinic acid is considered to be ineffective in the treatment of tumors with progression to the deep layer. Therefore, for such tumors, a method is required which can enhance the effectiveness of this therapy. We examined the anti tumor effect of the combination of PDT with 5-aminolevulinic acid hexyl ester (hALA) and hyperthermia (HT) in a squamous cell carcinoma (SCC) tumor model. METHODS: A tumor model was prepared by subcutaneously implanting SCC into nude mice, and treated with HT, PDT with hALA (hALA-PDT), or hALA-PDT combined with HT (PDT+HT). The treatment was performed by remodeled near infra-red irradiator which allows the generation of two types of rays for PDT and HT. With HT, the tumor was irradiated for raising the temperature with a light dose of 437.5 J/cm(2). With hALA-PDT, the tumor treated with 250 mg/kg hALA was irradiated with a light dose of 50 J/cm(2). With PDT+HT, the tumor was treated as for hALA-PDT except that the temperature was raised during irradiation with a light dose of 437.5 J/cm(2) (including light dose of 50 J/cm(2) for PDT). RESULTS: The tumor growth rates on Day 12 were 97.10% in HT, 67.55% in hALA-PDT and 33.90% in PDT+HT, and PDT+HT showed significant inhibitory effects on tumor growth, although the anti-tumoral effects of HT and hALA-PDT were not seen. CONCLUSION: hALA-PDT combined with HT demonstrated a significant inhibitory effect on the tumor growth of squamous cell carcinoma showing a progression in the deep layer. This suggests that this therapy is useful for tumors showing progression to the deep layer, which hALA-PDT alone is generally ineffective in treating.

Phosphodiesterase 4 regulates the migration of B16-F10 melanoma cells.

Phosphodiesterases (PDEs) are important regulators of signal transduction processes. Eleven PDE gene families (PDE1-11) have been identified and several PDE isoforms are selectively expressed in various cell types. PDE4 family members specifically hydrolyze cyclic AMP (cAMP). Four genes (PDE4A-D) are known to encode PDE4 enzymes, with additional diversity generated by the use of alternative mRNA splicing and the use of different promoters. While PDE4 selective inhibitors show therapeutic potential for treating major diseases such as asthma and chronic obstructive pulmonary disease, little is known concerning the role of PDE4 in malignant melanoma. In this study, we examined the role of PDE4 in mouse B16-F10 melanoma cells. In these cells, PDE4 activity was found to be ∼60% of total PDE activity. RT-PCR detected only PDE4B and PDE4D mRNA. Cell growth was inhibited by the cAMP analog, 8-bromo-cAMP, but not by the specific PDE4 inhibitors, rolipram and denbufylline, which increased intracellular cAMP concentrations. Finally, migration of the B16-F10 cells was inhibited by the PDE4 inhibitors and 8-bromo-cAMP, while migration was increased by a protein kinase A (PKA) inhibitor, PKI(14-22), and was not affected by 8-pCPT-2'-O-Me-cAMP, which is an analog of exchange protein activated by cAMP (Epac). The inhibitory effect of rolipram on migration was reversed by PKI(14-22). Based on these results, PDE4 appears to play an important role in the migration of B16-F10 cells, and therefore may be a novel target for the treatment of malignant melanoma.

Leiomyomatous hamartoma of the tongue in an infant: a case report.

A case of leiomyomatous hamartoma in the postmedian region of the dorsum of the tongue in a 3-year-old boy is reported. This lesion had been noticed at about 1 year of age but was left untreated. The intensity of the inner region of the mass was homogenous and similar to that of the surrounding tongue muscle on both T1- and T2-weighted images of an MRI. The mass was diagnosed as benign tumor of the tongue and resected. Histopathologically, nodular overgrowth of spindle cells containing eosinophilic cytoplasm was noted in the submucoepithelial connective tissue. In immunohistochemical staining, spindle cells were negative for S-100 protein and positive for vimentin and -SMA, suggesting that these cells were derived from smooth muscle. In the 10 months after surgery, there has been no recurrence of the lesion. To our knowledge, only 26 cases (including the present case) have been diagnosed histopathologically as leiomyomatous hamartoma in the oral cavity between 1945 and 2009. Clinical features, differential diagnosis, and treatment are discussed herein.

A case of desmoplastic ameloblastoma occupying maxillary sinus.

We report a rare case of desmoplastic ameloblastoma lesion that filled the entire maxillary sinus. The patient visited our hospital with a chief complaint of swelling around the upper left premolars. A panoramic X-ray captured an image of a mixture of ill-defined radiolucency and radiopacity from the swollen area to the maxillary sinus. Computed tomography (CT) and Magnetic resononce imaging (MRI) showed that the lesion occupied almost the entire left maxillary sinus and had entered the nasal cavity. A pathologic diagnosis of ameloblastoma was made after biopsy, and the tumor was removed and the marginal bone curetted under general anesthesia. A CT scan at 4 months postoperatively indicated the presence of residual and recurrent tumor in the area of the upper left lateral incisor, and removal and curettage were performed again. Recurrence may be detected relatively easily based on radiographic characteristics, and therefore follow-up with an X-ray examination such as a CT scan is important.

Expression and role of phosphodiesterase 5 in human malignant melanoma cell line.

BACKGROUND: Eleven phosphodiesterase (PDE) gene families (PDE1-11) have been identified, and some PDE isoforms are selectively expressed in various cell types. Previously, we reported PDE1, PDE3 and PDE4 expressions in human malignant melanoma cells. However, the expression and role of PDE5 in malignant melanoma cells is not clear. Therefore, we characterized PDE5 in human malignant melanoma MAA cells. MATERIALS AND METHODS: PDE5 activity and PDE5A mRNA expression were investigated in MAA cells. The full open reading frames for human PDE5A1 were sequenced. Effects of PDE5 inhibitors on cell growth were determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assays. RESULTS: PDE5 activity and PDE5A1 mRNA expression were detected in MAA cells. The nucleotide sequence of PDE5A1 was identical to that of human PDE5A1, previously published. Two PDE5 inhibitors inhibited the growth of cells. CONCLUSION: PDE5A1 mRNA is expressed and may play an important role in the growth of human malignant melanoma MAA cells.

A case of oral multiple primary cancer including Spindle Cell Carcinoma.

Spindle Cell Carcinoma (SPCC) is a relatively rare tumour that is classified as a subtype of squamous cell carcinoma (SCC). Histologically, SPCC is composed of a SCC region and epithelium-derived spindle cells with mesenchymal differentiation. We encountered an interesting case of multiple cancer including SPCC. A histopathologically atypical papillary lesion was found 13 years before our initial examination. Multiple verrucous leukoplakia later developed in the oral mucosa, for which an oral vitamin A derivative (a retinoid) was intermittently administered. Multiple cancer including SPCC subsequently developed in the lower gingiva. We investigated the case histologically and immunohistologically based on the concept of field cancerization.

Synergistic increase in osteosarcoma cell sensitivity to photodynamic therapy with aminolevulinic acid hexyl ester in the presence of hyperthermia.

OBJECTIVE: We observed that two osteosarcoma cell lines from the same tumor displayed marked differences in their sensitivities to photodynamic therapy (PDT) with aminolevulinic acid hexyl ester (hALA-PDT). We investigated why these two closely related lines had different hALA-PDT sensitivities and whether the PDT phototoxicity of the less sensitive cell line could be increased by a simultaneous application of hyperthermia (HT). METHODS: Flow cytometry was used to evaluate the intracellular accumulation of protoporphyrin IX (PpIX), a metabolic product of aminolevulinic acid, in two human mandibular osteosarcoma cell lines (HOSM-1 and HOSM-2) treated with HT, hALA-PDT, or hALA-PDT combined with HT (PDT + HT). With hALA-PDT, cells treated with 0.2 mM hALA were irradiated with a light dose of 10-80 J/cm(2) from a near-infrared irradiator. With PDT + HT, the cells were treated as for hALA-PDT except that the temperature was raised to 43.5 degrees C during irradiation. RESULTS: At 6 h after hALA treatment, HOSM-2 cells carried about 1.53-fold more PpIX than HOSM-1 cells. With hALA-PDT, the survival rate for HOSM-1 cells treated with 80 J/cm(2) irradiation was 35.7%, while that for HOSM-2 cells treated with 40-80 J/cm(2) was below 12%. With PDT + HT, the survival rate for HOSM-1 and HOSM-2 cells treated with 80 J/cm(2) irradiation was 14.1% and 10.7%, respectively. CONCLUSION: A combination therapy comprising hALA-PDT + HT treatment may be very useful for the treatment of tumors containing cells that are insensitive to hALA-PDT, such as the HOSM-1 cell line described in this study.

Phosphodiesterase 3 (PDE3): structure, localization and function.

Cyclic adenosine 3'5'-monophosphate (cAMP) and cyclic guanosine 3'5'-monophosphate (cGMP) are critical intracellular messengers involved in transduction of signals generated by a wide variety of extracellular stimuli, including growth factors, cytokines, peptide hormones, light and neurotransmitters. These messengers modulate many fundamental biological processes, including myocardial contractility, platelet aggregation, vascular smooth muscle relaxation, proliferation and apoptosis, etc. Cyclic nucleotide phosphodiesterases (PDEs) catalyze the hydrolysis of cAMP and cGMP, and are important in regulating intracellular concentrations and biological actions of these signal-transducing molecules. These enzymes contain at least 11 highly regulated and structurally related gene families (PDE1-11). In this review, we will discuss some general information of PDEs and then focus on PDE3 gene family, including the molecular biology, structure, function and potential as therapeutic targets. Furthermore, we show the possibilities of PDE3 as therapeutic targets in malignant tumor cells and salivary gland.

Characterization of phosphodiesterase 1 in human malignant melanoma cell lines.

BACKGROUND: Differentiation-inducing factor 1 [DIF-1; 1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl) hexan-1-one] from Dictyostelium discoideum exhibits antiproliferative activity in mammalian cells. We have previously shown that phosphodiesterase 1 (PDE1) is a pharmacological target of DIF-1, but there are no reports of PDE1 in human malignant melanoma cells. Therefore, we characterized PDE1 in human malignant melanoma MAA cells. MATERIALS AND METHODS: PDE1 mRNA expression was investigated in MAA cells. The full open reading frames for human PDE1C1 and PDE1C3 were cloned. Cell growth was determined by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay. RESULTS: PDE1C mRNA expression was detected in MAA cells. The nucleotide sequence of PDE1C1 was identical to that of human PDE1C1, previously published. At nucleotide 2246 in PDE1C3, A was replaced by G, but this did not change the encoded amino acid. Cell growth was inhibited by the PDE1 inhibitor vinpocetin. CONCLUSION: PDE1C mRNA is expressed and may play an important role in human malignant melanoma MAA cells.

Bax mRNA therapy using cationic liposomes for human malignant melanoma.

BACKGROUND: Bax is a pro-apoptotic molecule that functions as a tumor suppressor and Bax gene therapy has been examined for various cancers. Gene transfer by mRNA lipofection is more efficient than plasmid DNA lipofection and, in the present study, we examined the anti-tumor effects in human malignant melanoma cells (HMGs) using Bax mRNA lipofection. METHODS: Bax protein expression, cell growth inhibition, caspase-3 activity and apoptosis were examined in vitro. Liposome-Bax mRNA was applied locally once every 5 days for a total of five times to peripheral HMG tumors transplanted in nude mice. Tumor growth inhibition was evaluated by measuring the tumor volume and apoptosis was detected using a terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. RESULTS: Enhanced expression of Bax protein was observed following Bax mRNA transfer and cell survival was 59.8%. Caspase-3 activity and TUNEL-positive cells increased significantly following Bax mRNA lipofection compared to Bax plasmid transfer. In mice, tumor growth increased only slightly during liposome-Bax mRNA administration and the tumor volume on day 30 (10 days after completion of administration) was 36.7% of that in the saline control group. By contrast, Bax plasmid transfection resulted in little change in tumor growth compared to controls. CONCLUSIONS: Bax mRNA therapy using liposomes has stronger anti-tumor effects than Bax gene therapy using a plasmid, and the results suggest that Bax mRNA lipofection may be a viable treatment for malignant melanoma.

Radicular cyst in a deciduous tooth: a case report and literature review.

Radicular cyst is comparatively rare in primary teeth. The purposes of this paper were to report the case of a 6-year-old male child with a radicular cyst in a primary mandibular molar tooth, and discuss the causal factors and treatment of this lesion based on a review of the literature.

A case of submandibular gland mucocele.

Submandibular Gland Mucocele:The mucocele occuring in the submandibular region is rare, most cases originate in the sublingual gland. Here, we report a rare case of mucocele originating in the submandibular gland. In this report, we present such a case in a 7-year-old boy, who was treated by an extirpation of cyst with submandibular and sublingual gland