Background:Tumour stromal cells differ from its normal counterpart. We have shown that tumour endothelial cells (TECs) isolated from tumour tissues are also abnormal. Furthermore, we found that mRNAs of vascular endothelial growth factor-A (VEGF-A) and cyclooxygenase-2 (COX-2) were upregulated in TECs. Vascular endothelial growth factor-A and COX-2 are angiogenic factors and their mRNAs contain an AU-rich element (ARE). AU-rich element-containing mRNAs are reportedly stabilised by Hu antigen R (HuR), which is exported to the cytoplasm.Methods:Normal endothelial cell (NEC) and two types of TECs were isolated. We evaluated the correlation of HuR and accumulation of VEGF-A and COX-2 mRNAs in TECs and effects of HuR on biological phenotypes of TECs.Results:The HuR protein was accumulated in the cytoplasm of TECs, but not in NECs. Vascular endothelial growth factor-A and COX-2 mRNA levels decreased due to HuR knockdown and it was shown that these ARE-mRNA were bound to HuR in TECs. Furthermore, HuR knockdown inhibited cell survival, random motility, tube formation, and Akt phosphorylation in TECs.Conclusion:Hu antigen R is associated with the upregulation of VEGF-A and COX-2 mRNA in TECs, and has an important role in keeping an angiogenic switch on, through activating angiogenic phenotype in tumour endothelium.

HuR binds to AU-rich element-containing mRNA to protect them from rapid degradation. Here, we show that knockdown of HuR changes the oncogenic properties of oral cancer cells. Oral squamous cell carcinoma cell lines, HSC-3 and Ca9.22, which express HuR protein and cytoplasmic AU-rich element mRNA more abundantly than normal cells, were subjected to HuR knockdown. In the HuR-knockdown cancer cells, the cytoplasmic expression of c-fos, c-myc, and COX-2 mRNAs was inhibited compared with those in cells that had been transfected with a control small interfering RNA, and the half-lives of these mRNAs were shorter than those of their counterparts in the control cells. HuR-knockdown cells failed to make colonies in soft agar, suggesting that the cells had lost their ability for anchorage-independent cell growth. Additionally, the motile and invasive activities of the cells decreased remarkably by HuR knockdown. Furthermore, the expression of cell cycle-related proteins, such as cyclin A, cyclin B1, cyclin D1, and cyclin-dependent kinase 1, was reduced in HuR-knockdown cancer cells, and HuR bound to cdk1 mRNA to stabilize it. These findings suggest that HuR knockdown changes the features of oral cancer cells, at least in part, by affecting their cell cycle and shows potential as an effective therapeutic approach.

HuR, a ubiquitously expressed member of the Hu protein family that binds and stabilizes an AU-rich element (ARE)-containing mRNAs, is known to shuttle between the nucleus and the cytoplasm via several export pathways. When normal cells were treated with heat shock, HuR was exported to the cytoplasm in a chromosome maintenance region 1 (CRM1)-dependent manner. However, in this study, we demonstrate that HuR is exported to the cytoplasm in oral cancer cells even if the cells were treated with the inhibitor of the CRM1-independent export pathway. Immunohistochemical and biochemical analyses showed that HuR existed in both the cytoplasm and the nucleus in oral cancer cells, such as HSC-3 and Ca9.22, but existed entirely inside the nucleus in normal cells. AU-rich element-mRNAs were also exported to the cytoplasm and stabilised in the oral cancer cells, which were inhibited by HuR knockdown. This export of HuR was not affected by at least 7 h of treatment of leptomycin B (LMB), which is an inhibitor of the CRM1-dependent export pathway. These findings suggest that HuR is exported to the cytoplasm in oral carcinoma cells in a different manner from that of normal cells, and is likely to occur through the perturbation of a normal export pathway.

The control of distant metastasis in oral squamous cell carcinoma is an important determinant of improved prognosis. The study aimed to identify risk factors for distant metastasis in patients with locoregionally controlled oral carcinoma. We identified 982 patients with oral squamous cell carcinoma treated at our hospital between January 2008 and December 2017. After excluding patients with distant metastasis at initial treatment, patients with metastasis to the oral cavity, those receiving palliative treatment, and those lacking follow-up data, 941 patients were selected. Finally, among these 941 patients, 887 with locoregionally controlled oral squamous cell carcinoma were included in the study. Among the 887 patients, 36 had confirmed distant metastasis (4.1%), and the lung was the most common site (31/36 patients, 86.1%). Multivariate analysis showed that the incidence of primary intraosseous carcinoma of the mandible, cervical lymph node metastasis at levels IV and V, and the presence of pathological extranodal extension were significant risk factors for distant metastasis. When treating patients with oral squamous cell carcinoma who are positive for the aforementioned risk factors, the possibility of developing distant metastases must be accounted for, and aggressive treatment should be planned accordingly.

Abstract.A 78-year-old male patient was referred to the Department of Oral Surgery, Hokuto Hospital (Obihiro, Japan) for painless swelling on the left neck and tongue. Histopathological examination of a biopsy specimen resulted in a diagnosis of squamous cell carcinoma of the tongue. Imaging examinations revealed cervical lymph node metastases on both sides, along with diffuse uptake of 18 F-fluorodeoxyglucose (FDG) in the bone marrow of the spine and pelvis. Hematologic tests revealed an increased white blood cell (WBC) count and serum concentrations of granulocyte colony stimulating factor (G-CSF). These findings suggested a G-CSF producing tumor, with fluctuations of WBC count, serum G-CSF concentration, and FDG uptake in the bone marrow, associated with tumor shrinkage and enlargement, an indicator of tumor status. IntroductionGranulocyte colony stimulating factor (G-CSF) is a cytokine mainly produced by macrophages, fibroblasts and endothelial cells in an inflammatory milieu. G-CSF stimulates neutrophil precursors, resulting in an increase in neutrophils, and recruits neutrophils from the bone marrow to peripheral blood. G-CSF is an important factor in infection prophylaxis, and recombinant G-CSF is universally used to treat neutropenia (1). G-CSF is also produced by non-hematologic malignancies with high leukocyte counts, consisting predominantly of neutrophils, in patients without infectious diseases. Most of these G-CSF producing tumors are present in the lungs (2), with tumors in the oral regions being rare. This report describes a patient with a tongue carcinoma producing G-CSF, as well as showing diffuse uptake of FDG in the bone marrow. Case reportIn July 2013, a 78-year-old man visited the Department of Oral Surgery, Hokuto Hospital (Obihiro, Japan) with a 2-week history of painless swelling on the left neck and tongue. The patient had no systemic complications and no significant family history. Some cervical lymph nodes on both sides were palpable (Fig. 1A). Intra-oral examination showed a tumor with induration about 40 mm in diameter on the left side of the tongue (Fig. 1B). Cytological examination of a swollen left lymph node showed atypical squamous cells, and pathological examination of a biopsy of the tongue tumor revealed a squamous cell carcinoma. A computed tomography (CT) scan with contrast demonstrated a large lateral oral tongue tumor of diameter 42 mm, without extension to the extrinsic muscles of the tongue; and some metastatic cervical lymph nodes that were enlarged, nonhomogeneously enhanced, and partially necrotic. Metastatic disease of left middle jugular lymph node was >30 mm in maximum diameter (Fig. 2). 18 F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT showed abnormally high uptake by the tongue tumor (maximum standardized uptake value [SUVmax] 22.19) and by the four large metastatic nodes, with the large left middle jugular node having an SUVmax of 14.43 (Fig. 3A). Diffuse FDG uptake was also observed in the bone marrow of the spine and pelvis (Fig. 3B). These f...