坂本 洋右

Ameloblastic carcinoma (AC) is an odontogenic malignant tumor which combines the histological features of ameloblastoma and cytologic atypia. The key point of the diagnosis and clinical characteristics of AC have not been well defined, as it is a rare type of tumor. Hence, in this study, we present’ for better clarity the diagnostic flowchart for AC, ameloblastoma, and metastasizing ameloblastoma.

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 β1/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.

Dermoid cysts, which are lined by ectoderm elements, typically arise in skin, testicles, and ovaries. These cysts mostly occur during the second or third decade of life and rarely present in children. We describe a rare case of a dermoid cyst in a 6-year-old Japanese girl. Examination showed a smooth, well-defined cystic swelling approximately 30 × 20 mm2 in the midline of the oral floor. The cyst was excised via the intraoral approach under general anesthesia. The histopathologic diagnosis of a dermoid cyst was made. The clinical outcome was satisfactory without postoperative complications during the 26-month follow-up period.

Unc-93 homolog B1 (UNC93B1), a transmembrane protein, is correlated with immune diseases, such as influenza, herpes simplex encephalitis, and the pathogenesis of systemic lupus erythematosus; however, the role of UNC93B1 in cancers including human oral squamous cell carcinomas (OSCCs) remains unknown. In the current study, we investigated the UNC93B1expression level in OSCCs using quantitative reverse transcription-polymerase chain reaction, immunoblot analysis, and immunohistochemistry. Our data showed that UNC93B1 mRNA and protein expressions increased markedly (p < 0.05) in OSCCs compared with normal cells and tissues and that high expression of UNC93B1 in OSCCs was related closely to tumoral size. UNC93B1 knockdown (shUNC93B1) OSCC cells showed decreased cellular proliferation by cell-cycle arrest in the G1 phase with up-regulation of p21Cip1 and down-regulation of CDK4, CDK6, cyclin D1, and cyclin E. We also found that granulocyte macrophage colony-stimulating factor (GM-CSF) was down-regulated significantly (p < 0.05) in shUNC93B1 OSCC cells. Moreover, inactivation of GM-CSF using neutralization antibody led to cell-cycle arrest at the G1 phase similar to the phenotype of the shUNC93B1 cells. The current findings indicated that UNC93B1 might play a crucial role in OSCC by controlling the secretion level of GM-CSF involved in tumoral growth and could be a potential therapeutic target for OSCCs.

Cetuximab, an inhibitor of the epidermal growth factor receptor that is used widely to treat human cancers including oral squamous cell carcinoma (OSCC), has characteristic side effects of skin rash and hypomagnesemia. However, the mechanisms of and therapeutic agents for skin rashes and hypomagnesemia are still poorly understood. Our gene expression profiling analyses showed that cetuximab activates the p38 MAPK pathways in human skin cells (human keratinocyte cell line [HaCaT]) and inhibits c-Fos-related signals in human embryonic kidney cells (HEK293). We found that while the p38 inhibitor SB203580 inhibited the expression of p38 MAPK targets in HaCaT cells, flavagline reactivated c-Fos-related factors in HEK293 cells. It is noteworthy that, in addition to not interfering with the effect of cetuximab by both compounds, flavagline has additive effect for OSCC growth inhibition in vivo. Collectively, our results indicate that combination of cetuximab and these potential therapeutic agents for cetuximab-related toxicities could be a promising therapeutic strategy for patients with OSCC.

Tripartite motif family-like 2 (TRIML2), a member of the TRIM proteins family, is closely related to Alzheimer's disease, however, no studies of TRIML2 have been published in the cancer research literature. In the current study, we investigated the expression level of TRIML2 and its molecular mechanisms in human oral squamous cell carcinoma (OSCC); reverse transcriptase-quantitative polymerase chain reaction, immunoblot analysis, and immunohistochemistry showed that TRIML2 is up-regulated significantly in OSCCs in vitro and in vivo. TRIML2 knockdown OSCC cells showed decreased cellular proliferation by cell-cycle arrest at G1 phase that resulted from down-regulation of CDK4, CDK6, and cyclin D1 and up-regulation of p21Cip1 and p27Kip1. Surprisingly, resveratrol, a polyphenol, led to not only down-regulation of TRIML2 but also cell-cycle arrest at G1 phase similar to TRIML2 knockdown experiments. Taken together, we concluded that TRIML2 might play a significant role in tumoral growth and that resveratrol may be a new drug for treating OSCC by interfering with TRIML2 function.

Centromere protein N (CENP-N), an important member of the centromere protein family, is essential for kinetochore assembly and chromosome segregation; however, the relevance of CENP-N in cancers remains unknown. The aim of this study was to investigate CENP-N expression and its functional mechanisms in oral squamous cell carcinoma (OSCC). CENP-N expression was up-regulated significantly in vitro and in vivo in OSCCs. Overexpressed CENP-N was closely (p < 0.05) correlated with tumor growth using quantitative reverse transcriptase-polymerase chain reaction, immunoblot analysis, and immunohistochemistry. CENP-N knockdown (shCENP-N) cells showed depressed cellular proliferation by cell-cycle arrest at the G1 phase with up-regulation of p21Cip1 and p27Kip1 and down-regulation of cyclin D1, CDK2, and CDK4. Interestingly, we newly discovered that calcitriol (1, 25-dihydroxyvitamin D3) controlled the CENP-N expression level, leading to inhibition of tumor growth similar to shCENP-N cells. These results suggested that CENP-N plays a critical role in determining proliferation of OSCCs and that calcitriol might be a novel therapeutic drug for OSCCs by regulating CENP-N.

Filamin-binding LIM protein 1 (FBLIM1) is related to regulation of inflammatory responses, such as chronic recurrent multifocal osteomyelitis; however, the relevance of FBLIM1 in oral squamous cell carcinoma (OSCC) is unknown. The aim of the current study was to elucidate the possible role of FBLIM1 in the carcinogenesis of OSCC. We analyzed FBLIM1 expression using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), immunoblot analysis, and immunohistochemistry. The expression levels of FBLIM1 were up-regulated significantly (P < 0.05) in OSCC-derived cell lines and primary OSCCs specimens compared with normal counterparts. FBLIM1 expression also was correlated with the primary tumoral size (P < 0.05) and vascular invasion (P < 0.05). We then assessed tumoral progression after treatment with FBLIM1 siRNA and clopidogrel, an antiplatelet agent. Similar to the FBLIM1 knockdown effect, clopidogrel-treated cells had attenuated functions of proliferation, migration, and invasiveness. Interestingly, clopidogrel treatment led to down-regulation of epidermal growth factor receptor (EGFR) and FBLIM1. These findings identify FBLIM1 as a putative therapeutic target by using clopidogrel for inhibiting over activation of EGFR signaling to prevent OSCC malignancy.

Multiple coagulation factor deficiency protein 2 (MCFD2), a binding partner of lectin mannose binding 1 (LMAN1), causes combined deficiencies of coagulation factors V and VIII. MCFD2 function in inherited hematologic disorders is well elucidated; however, little is known about its role in human tumorigenesis. The aim of the current study was to investigate the states of MCFD2 in oral squamous cell carcinoma (OSCC). The expression of MCFD2 was up-regulated significantly in all cell lines examined. Evaluation of the cellular functions associated with tumoral metastasis showed that MCFD2 knockdown (shMCFD2) cells exhibited significantly lower cellular invasiveness and migration and higher cellular adhesion compared with shControl cells. Of note, shMCFD2 cells also showed weak immunoreactivity of LMAN1 and a lower secretion level of galactoside-binding soluble 3 binding protein (LGALS3BP). In addition to in vitro validation, clinical data on 70 patients with OSCC indicated that state of MCFD2 expression level is associated with regional lymph node metastasis. Altogether, we have demonstrated that MCFD2 promotes cancer metastasis by regulating LMAN1 and LGALS3BP expression levels. Hence, MCFD2 may represent a promising candidate for a novel therapeutic target for patients with metastatic OSCCs.

Angiopoietin-1 (Ang1) is a binding partner of endothelial cell-specific tyrosine-protein kinase receptor (Tie2), which serves important roles in vascular development and angiogenesis. Tie2 is closely associated with the metastasis of oral squamous cell carcinomas (OSCCs) however, little is known about the correlation between Tie2 and Ang1. In the present study, the functional mechanisms of the Tie2/Ang1 interaction were investigated using Tie2 overexpressed (oeTie2) OSCC cells and recombinant Ang1 protein. oeTie2 cells had increased cell-cell and cell-extracellular matrix adhesions compared with the control cells. Additionally, the adhesive activities increased following treatment with exogenous Ang1, indicating that Ang1 directly enhances Tie2 functions. In the clinical OSCC data from 10 cases positive for regional lymph node metastasis, all cases were negative for Tie2 expression and eight cases (80%) were negative for Ang1 expression. These results suggest that Tie2 and Ang1 serve important roles in cancer metastasis and may be potential biomarkers and therapeutic targets for OSCC metastasis.

症例は91歳女性で、歩行中に転倒してオトガイ部を強打し受傷した。両側下顎骨骨折の診断を受けた。パノラマX線写真およびCT写真にて右側下顎骨骨体部(第一・第二小臼歯相当部)に骨折線、左側下顎骨骨体部(中切歯から第一大臼歯相当部にかけて)に頬舌側的に骨折線を認めた。また、両側下顎骨骨折によるオトガイ棘の後方偏位およびそれに伴った舌根沈下と上気道狭窄を認めた。呼吸不全やSpO2の低下は認めなかったが、画像検査により舌根沈下および上気道狭窄を疑い、呼吸管理目的に入院とした。第10病日に全身麻酔下において両側下顎骨骨折観血的整復固定術を施行した。気道確保は経鼻挿管で行った。手術は口内法で行った。創部への感染は認めず、術後第9病日で軽快退院した。術後パノラマX線写真にて下顎骨の整復、CT写真で下顎骨整復による舌根沈下および上気道狭窄が改善していることを確認した。術後4ヵ月に下顎義歯を新製した。術後18ヵ月経過した現在、経過良好である。

周術期口腔機能管理は、がん治療における重要な支持療法として認識され、多くの医療機関にて実施されている。対象患者・対象疾患が、「全身麻酔下で頭頸部領域、呼吸器領域、消化器領域などの悪性腫瘍の手術を行う患者」、「全身麻酔下で臓器移植手術又は心臓血管外科手術などを行う患者」、「放射線治療や化学療法を行う患者」と、がん治療をする上で重要な役割を果たしている。そのため、限られた資源(医療費、人的資源等)を有効に活用するシステムの確立が望まれている。手術リスク評価法The Estimation of Physiologic Ability and Surgical Stress scoring system(以下-E-PASS)は、1999年に芳賀らにより提唱され、患者の生理機能、手術侵襲度から、術後合併症のリスクを把握することができ、消化器外科領域で有用性が報告されている。今回われわれは、千葉大学医学部附属病院にて施行した胃がん症例において、E-PASSによる分析を含めた術後合併症発症率と周術期口腔機能管理との関連性について検討したため報告する。対象は2014年1月から2016年8月までに当院にて手術をした胃がん患者264人を対象とした。当該期間に周術期口腔機能管理を実施した患者を周術期口腔機能管理施行群、当科未受診で周術期口腔機能管理を実施していない患者を周術期口腔機能管理非施行群とした。術後合併症は過去の当院におけるデータから、誤嚥性肺炎と創部治癒不全とした。手術リスク評価法E-PASSとは患者の生理機能を表す術前リスクスコアPreoperative risk score(以下PRS)と、手術の大きさを表す手術侵襲スコアSurgical stress score(以下SSS)、およびこの両者から規定される総合リスクスコアComprehensive risk score(以下CRS)から成る。このCRSの値によって胃がん手術患者を2群に分けて、周術期口腔機能管理施行群と非施行群の術後合併症発症率について比較検討を行った。対象群では性別は男性192名、女性72名と2.7:1で男性が多く、年齢分布では男女とも70歳代がピークで、男性では60歳代〜70歳代で全体の約70%を占めていた。女性も同様に60歳代〜70歳代で全体の約76%を占めていた。最年少は32歳、最高年齢は94歳で、平均年齢は69歳であった。周術期口腔機能管理施行群は男性74名、女性25名、周術期口腔機能管理非施行群は男性118名、女性47名であった。それぞれの群で胃がんに対する術式に差は認めなかった。CRSが0.2以上の患者において、周術期口腔機能管理施行群は、非施行群と比べて術後合併症発症率の有意な減少を認めた。CRSが0.2以上の患者は、0.2未満の患者と比べて年齢層が高く、体重あたりの出血量が多い傾向にあり、手術時間も長かった。また、内視鏡・腹腔鏡ではなく開腹・開胸手術が多かった。このことから、年齢や手術侵襲も術後合併症発症のリスク因子であり、それらを考慮した周術期口腔機能管理を行うことで、より効果的な結果を得ることができると考えられた。またこのような情報を術前に得ることができれば、周術期口腔機能管理を行う上での客観的なデータとなるため、インフォームド・コンセントを行う場合に、患者サイドに分かりやすい情報となり得ると思われた。CRSと術後合併症の関係は消化器疾患に限らず、呼吸器外科手術、心臓血管外科手術でも有用であるとの結果が得られており、今後はこれらの領域の手術と周術期口腔機能管理との関連性について、さらなる調査が必要であると考えられた。総合リスクスコアCRSの値が0.2以上において、周術期口腔機能管理施行群は非施行群に比べ、術後合併症発症率の有意な低下を認めた。このことより、総合リスクスコアCRSの値が周術期口腔機能管理を集中的に行う患者の指標になり、限られた医療資源、人材を有効活用できると考えられるが、CRSの値のみではなく、口腔の評価をスコア化し関連付けることができれば、より有益な指標になると考えられた。(著者抄録)

Translocation associated membrane protein 2 (TRAM2) has been characterized as a component of the translocon that is a gated channel at the endoplasmic reticulum (ER) membrane. TRAM2 is expressed in a wide variety of human organs. To date, no information is available regarding TRAM2 function in the genesis of human cancer. The purpose of this study was to investigate the status of the TRAM2 gene in oral squamous cell carcinoma (OSCC) cells and clinical OSCC samples. Using real-time quantitative reverse transcriptase-polymerase chain reaction, Western blotting analysis, and immunohistochemistry, we detected accelerated TRAM2 mRNA and protein expression levels both in OSCC-derived cell lines and primary tumors. Moreover, TRAM2-positive OSCC tissues were correlated closely (P<0.05) with metastasis to regional lymph nodes and vascular invasiveness. Of note, knockdown of TRAM2 inhibited metastatic phenotypes, including siTRAM2 cellular migration, invasiveness, and transendothelial migration activities with a significant (P<0.05) decrease in protein kinase RNA(PKR) - like ER kinase (PERK) and matrix metalloproteinases (MMPs) (MT1-MMP, MMP2, and MMP9). Taken together, our results suggested that TRAM2 might play a pivotal role in OSCC cellular metastasis by controlling major MMPs. This molecule might be a putative therapeutic target for OSCC.