CD44high/ESAlow squamous cell carcinoma cell-derived prostaglandin E2 confers resistance to 5-fluorouracil-induced apoptosis in CD44high/ESAhigh cells.

We previously found that CD44high/ESAlow head and neck squamous cell carcinoma (HNSCC) cells harboring high dihydropyrimidine dehydrogenase (DPD) expression exhibited potent resistance to 5-fluorouracil (5-FU)-induced apoptosis. In addition, susceptibility of HNSCC cells to 5-FU was compromised in the presence of cyclooxygenase 2 (COX2)-derived prostaglandin E2 (PGE2). In this study, we examined 5-FU-induced apoptosis in sorted cell populations (i.e., CD44high/ESAlow, CD44high/ESAhigh, and CD44low cells from the HNSCC cell line A-253) to clarify the anti-apoptotic effect of PGE2 on CD44high cells. Notably, CD44high/ESAlow cells upregulated PGE2, compared with other populations. To investigate the effect of CD44high/ESAlow cell-derived PGE2 on CD44high/ESAhigh cells, direct and indirect co-culture assays were performed. The percentage of apoptotic cells in a culture of CD44high/ESAhigh cells was significantly reduced when they were directly and indirectly co-cultured with CD44high/ESAlow cells. Furthermore, 5-FU-induced apoptosis of CD44high/ESAhigh cells was significantly increased in the presence of an inhibitor of the PGE2 receptors (EP1/EP2) when CD44high/ESAhigh cells were co-cultured with CD44high/ESAlow cells. These results suggest that CD44high/ESAlow cell-derived PGE2 may contribute to the inhibition of 5-FU-induced apoptosis in CD44high/ESAhigh cells. Additionally, NR4A2 knockdown enhances 5-FU-induced apoptosis in CD44high/ESAhigh cells, suggesting that PGE2 attenuates 5-FU-induced apoptosis in an NR4A2-dependent manner in CD44high/ESAhigh cells. In conclusion, CD44high/ESAlow cells contribute to induction of resistance to 5-FU in CD44high/ESAhigh cells through provision of PGE2. CD44high/ESAlow cell-targeted therapy may be effective in treatment of HNSCC.

Preoperative oral health care reduces postoperative inflammation and complications in oral cancer patients.

The records of 70 patients with oral cancer who were treated at a single institution between 2008 and 2014 were reviewed. The body temperature, white blood cell count, and C-reactive protein (CRP) levels were compared between those who had received preoperative oral care (oral care group) and those who had not received any (non-oral care group). When the patients were divided into those who underwent minimally invasive surgery and those who underwent severely invasive surgery, the mean CRP level in the early postoperative period was lower in the oral care group as compared with the non-oral care group in those who underwent minimally invasive surgery as well as those who underwent severely invasive surgery. However, the mean CRP level was most evidently reduced in the severely invasive group on days 1 and 3-5. However, no significant differences were observed with regard to the percentage of postoperative infectious complications (for example, surgical site infection, anastomotic leak and pneumonia) between the oral care (13.6%) and non-oral care (20.8%) groups, though a reduced prevalence of postoperative complications following preoperative oral care was noted. The results of the present study suggest that preoperative oral care can decrease inflammation during the early postoperative stage in patients with oral cancer who undergo severely invasive surgery.

CD44(high) /ALDH1(high) head and neck squamous cell carcinoma cells exhibit mesenchymal characteristics and GSK3ß-dependent cancer stem cell properties.

BACKGROUND: CD44 and aldehyde dehydrogenase 1 (ALDH1) have been shown to be useful markers for identification of cancer stem cells (CSCs). We previously reported that glycogen synthase kinase 3ß (GSK3ß) is involved in regulation of the self-renewal ability of head and neck squamous cell carcinoma (HNSCC) CSCs. The purpose of the present study was to clarify the role of GSK3ß in CD44(high) /ALDH1(high) HNSCC cells. METHODS: Cells with greater expression of CD44 and higher ALDH1 enzymatic activity were FACS sorted from the OM-1 HNSCC cell line. The self-renewal ability of CD44(high) /ALDH1(high) cells was then examined using a tumor sphere formation assay. mRNA expressions of the stem cell markers Sox2, Oct4, and Nanog, as well as GSK3ß were evaluated by real-time RT-PCR. RESULTS: CD44(high) /ALDH1(high) cells exhibited higher tumor sphere forming ability and increased expression of stem cell markers as compared with CD44(high) /ALDH1(low) cells. Interestingly, spindle-shaped cells positive for vimentin were found in the CD44(high) /ALDH1(high) but not the CD44(high) /ALDH1(low) cell population. In addition, the ALDH1 activity and sphere forming ability of CD44(high) /ALDH1(high) cells was significantly inhibited by GSK3ß knockdown. On the other hand, CD44(high) /ALDH1(low) cells exhibited high epidermal growth factor receptor (EGFR) expression and increased cell growth. CONCLUSIONS: Our results show that GSK3ß plays a major role in maintenance of stemness of CD44(high) /ALDH1(high) HNSCC cells. Additionally, they indicate a close relationship between CSC and mesenchymal characteristics in HNSCC.

Clinicopathological analysis of salivary gland carcinomas and literature review.

Malignant salivary gland tumors are rare and exhibit a broad spectrum of phenotypic heterogeneity. The objective of this study was to investigate prognostic factors in patients with salivary gland carcinomas and review the results in light of other reports. We retrospectively reviewed 40 patients with primary salivary gland carcinomas who were diagnosed and treated at our institution between 1991 and 2014. Of the 40 tumors, 19 (47.5%) were mucoepidermoid carcinomas, 11 (27.5%) were adenoid cystic carcinomas, 7 (17.5%) were acinic cell carcinomas, 2 (5.0%) were myoepithelial carcinomas and 1 (2.5%) was a squamous cell carcinoma. Clinically positive lymph nodes were present in 4 patients (10.0%). As regards clinical stage, 15 cases (37.5%) were stage I, 13 (32.5%) were stage II, 1 (2.5%) was stage III and 11 (27.5%) were stage IVA. The majority of the patients (97.5%) were treated with surgery, of whom 25 (62.5%) received surgery alone and 14 (35.0%) underwent surgery in combination with chemotherapy or chemotherapy and radiotherapy. The median follow-up time for all the patients was 48 months. The disease-specific survival rate at 5 years was 87.1%. We identified a significant correlation between poor survival rate and histological grade (intermediate/high), tumor size (T3/T4), lymph node metastasis (node-positive) and clinical stage (III/IV) using the Kaplan-Meier method (P<0.05 for each). In addition, the Cox proportional hazards regression analysis confirmed that lymph node metastasis and tumor size were independent prognostic factors for disease-specific survival (hazard ratio = 18.7 and 15.1, respectively; P=0.023 and 0.037, respectively). Furthermore, tumor size was found to be a predictive factor regarding recurrence in the multivariate logistic regression analysis (odds ratio = 8.35; P=0.025). Our results suggest that lymph node metastasis and tumor size are significant prognostic factors for patients with salivary gland carcinomas.

Elevation in 5-FU-induced apoptosis in head and neck cancer stem cells by a combination of CDHP and GSK3ß inhibitors.

BACKGROUND: Cancer stem cells (CSCs) are involved in both tumourigenesis and in tumour recurrence after therapy. In head and neck squamous cell carcinoma (HNSCC), there are two biologically different CSC phenotypes both of which express high levels of CD44 but differ in their expression levels of epithelial-specific antigen (ESA). One phenotype is CD44(high)/ESA(high) and has epithelial features (Epi-CSCs), while the other is CD44(high) /ESA(low), has undergone epithelial to mesenchymal transition (EMT-CSCs), has mesenchymal features and is migratory (Biddle et al., 2011). CSCs are resistant to therapeutically induced apoptosis but the molecular mechanisms by which they develop apoptotic resistance remains unclear. However, glycogen synthase kinase 3ß (GSK3ß) contributes to regulation of both the self-renewal and switching of these two CSC phenotypes (Shigeishi et al., 2013). METHODS: CD44(high) /ESA(low), CD44(high) /ESA(high) and CD44(low) cells were FACS sorted from the HNSCC cell line LUC4, and 5-FU-induced apoptosis was analysed by Annexin V staining followed by flow cytometry analysis. RESULTS: CD44(high) /ESA(low) cells exhibited marked resistance to 5-FU-induced apoptosis and had high expression of dihydropyrimidine dehydrogenase (DPD). The DPD inhibitor, 5-chloro-2, 4-dihydroxypyridine (CDHP) significantly enhanced 5-FU-induced apoptosis of CD44(high)/ESA(low) cells. Inhibition of GSK3ß induced CD44(high) /ESA(low) cells to undergo mesenchymal-to-epithelial transition (MET) to CD44(high)/ESA(high) cells and pre-existing CD44(high) /ESA(high) cells to differentiate. Apoptosis induced by 5-FU was thus facilitated. Combination of both CDHP and GSK3ß inhibitors markedly enhanced 5-FU-induced apoptosis of CD44(high) /ESA(low) cells. CONCLUSIONS: Our results suggest potentially new approaches for the elimination of the therapy resistant HNSCC CSC population.