Retrospective study on the therapeutic efficacy of zinc acetate hydrate administration to patients with hypozincemia-induced dysgeusia.

BACKGROUND: Dysgeusia is a relatively early symptom of zinc deficiency, and zinc replacement is effective in treating dysgeusia. The administration of zinc acetate hydrate (ZAH) was approved in 2017 for patients with hypozincemia in Japan. This retrospective study was conducted to explore the efficacy and safety of ZAH administration in patients with hypozincemia-induced dysgeusia. METHODS: Patients with hypozincemia-induced dysgeusia who visited our hospital from May 2013 to December 2019 were included in this study. ZAH (zinc content; 50 mg/day) was administered to 42 patients for 24 weeks. The taste test was performed using the filter paper disk method, and the total cognitive thresholds of the left and right chorda tympani regions were used. Changes in taste function, serum zinc and copper levels, and copper/zinc ratio were analyzed. A total of 28 patients who received polaprezinc (PPZ, zinc content; 34 mg/day) for 24 weeks, who were prescribed until ZAH was approved, were registered as controls. RESULTS: Serum zinc levels at 12 and 24 weeks after ZAH or PPZ administration were higher than those before administration. These levels were significantly higher in the ZAH-treated group than in the PPZ-treated group. However, serum copper levels did not significantly change before and after administration. In the taste test, the taste thresholds for the acidity and salty at 12 and 24 weeks after ZAH administration were significantly decreased compared to before administration. In contrast, in the PPZ group, the taste thresholds for the acidity and salty were significantly decreased 24 weeks after administration. CONCLUSIONS: ZAH (50 mg/day) administration was effective in improving the gustatory sensitivity of patients with dysgeusia and hypozincemia 12 weeks after administration without affecting the serum copper level. ZAH was also more effective than PPZ.

Clinical significance of integrin αV and ß superfamily members and focal adhesion kinase activity in oral squamous cell carcinoma: a retrospective observational study.

Objectives: Integrins are heterodimeric transmembrane plasma membrane proteins composed of α- and ß-chains. They bind to extracellular matrix (ECM) and cytoskeletal proteins as ECM protein receptors. Upon ECM protein binding, integrins activate focal adhesion kinase (FAK) and transduce various signals. Despite their importance, integrin and FAK expression in oral squamous cell carcinoma (OSCC) tissue and the prognosis of patients with OSCC remains elusive. Methods: In a retrospective observational study, we immunohistochemically evaluated integrin αV, ß1, ß3, ß5, ß6, FAK, and phosphorylated-FAK (pFAK) expressions as prognostic predictors in 96 patients with OSCC. Patients were classified as positive or negative based on staining intensity, and clinicopathologic characteristics and survival rates of the two groups were compared. The association between above integrin-related proteins and PD-1 or PD-L1 in OSCC tissues was investigated. Results: We observed immunohistochemical integrin αV, ß1, ß6, ß8, and FAK expressions in the cell membrane and cytoplasm but not integrin ß3 and ß5 in the OSCC tissues. pFAK was expressed in the cytoplasm of OSCC cells. The overall survival rate significantly decreased in pFAK-positive OSCC patients compared to the negative group, and cervical lymph node metastasis significantly increased in integrin ß8-positive patients with OSCC (p < 0.05). No association between integrin-related proteins and PD-1 or PD-L1 in OSCC tissues was observed. Conclusion: Our results indicate that pFAK and integrin ß8 are prognostic factors for OSCC. Therefore, pFAK- and integrin ß8-targeting new oral cancer diagnostic and therapeutic methods hold a promising potential.

Interaction of Integrin αvß8 With Type I Collagen Promotes Squamous Cell Carcinoma Cell Motility via RAC1 Activation.

BACKGROUND/AIM: The interaction of integrin αvß8 with type I collagen was shown to promote oral squamous cell carcinoma (SCC) cell proliferation via the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. However, the role of integrin αvß8 in SCC progression remains poorly understood. In this study, the role of integrin αvß8 in oral SCC progression was therefore investigated. MATERIALS AND METHODS: Integrin αv and ß8 protein expression in oral SCC cells was examined by western blotting. Oral SCC cell motility was investigated using modified Boyden chamber assays. Behavior of oral SCC cells was examined in three-dimensional culture using type I collagen gel. Ras homolog family member A (RHOA), Ras-related C3 botulinum toxin substrate 1 (RAC1), and cell division control protein 42 homolog (CDC42) activity of oral SCC cells was analyzed by pull-down assays. RESULTS: SCC cells with high integrin αvß8 expression levels had a high ability to migrate on type I collagen and exhibited enhanced invasion into type I collagen gel. In SCC cells with high integrin αvß8 expression level, cultivation on type I collagen induced RAC1 activation. Treatment with RAC1 inhibitor reduced type I collagen-induced motility of SCC cells. Down-regulation of integrin ß8 by specific antisense oligonucleotide reduced type I collagen-induced RAC1 activation and suppressed cell motility and invasion into type I collagen gel. CONCLUSION: The interaction of integrin αvß8 with type I collagen facilitates SCC cell motility and invasion via RAC1 activation. Therefore, integrin αvß8 and RAC1 may represent new targets for inhibiting metastasis and invasion in patients with oral SCC.

VEGF-A promotes the motility of human melanoma cells through the VEGFR1-PI3K/Akt signaling pathway.

Vascular endothelial growth factor A (VEGF-A) and its receptors (VEGFR1 and R2) play important roles in the progression of malignant melanoma through tumor angiogenesis. However, it is not clear whether the VEGF-A/VEGFR1 signaling pathway is involved in the proliferation and migration of melanoma cells. Thus, the effect of VEGF-A on cell migration was investigated in human melanoma cell lines. Of several splicing variants of VEGF-A, VEGF165 is the most abundant and responsible for VEGF-A biological potency. VEGF165 facilitated the migration of melanoma cells in both a chemotactic and chemokinetic manner, but cell proliferation was not affected by VEGF165. VEGF165 also induced the phosphorylation of Akt. In addition, VEGF165-induced cell migration was inhibited significantly by VEGFR1/2 or a VEGFR1-neutralizing antibody. Furthermore, the downregulation of VEGFR1 via the transfection of VEGFR1-targeting antisense oligonucleotides suppressed VEGF165-induced cell migration. Moreover, wortmannin, an inhibitor of phosphatidylinositol-3 kinase (PI3K) in the PI3K/Akt pathway, suppressed VEGF165-induced Akt phosphorylation and VEGF165-induced cell migration. These findings suggest that the motility of melanoma cells is regulated by signals mediated through the PI3K/Akt kinase pathway with the activation of VEGFR1 tyrosine kinase by VEGF165. Thus, the downregulation of signaling via VEGF-A/VEGFR1 might be an effective therapeutic approach that could prevent the progression of malignant melanoma.

Reconstruction of an upper lip and intraoral defect following resection of an upper lip melanoma using a lower lip musculomucosal flap combined with a tongue flap.

Restoring the cosmetic and functional aspects of the lip after tumor resection is challenging. We report a case of reconstruction for a defect due to resection of a melanoma using a lower lip musculomucosal flap combined with a tongue flap. A 20-year-old man was referred to our hospital and diagnosed with malignant melanoma with metastatic right submaxillary lymph nodes. We excised the tumor with neck dissection. We excised not only the right upper lip mucosa but also the gum, including some orbicularis oris muscle and alveolar bone from the right canine tooth to the left central incisor tooth. The defect was simultaneously reconstructed using both, a lower lip musculomucosal flap and a tongue flap. Revisional operation to remove contraction of a postoperative scar and the right vermillion border collection was performed at 3 months after the initial operation. There had been no functional and cosmetic trouble of the upper lip.

Induction of alpha2-antiplasmin inhibits E-cadherin processing mediated by the plasminogen activator/plasmin system, leading to suppression of progression of oral squamous cell carcinoma via upregulation of cell-cell adhesion.

The plasminogen activator/plasmin system is one of the main protease systems involved in tumor cell invasion and metastasis. Our previous study has shown that plasmin degrades E-cadherin and promotes cell dissemination by downregulation of E-cadherin-mediated cell-cell adhesion in oral squamous cell carcinoma (SCC) cells. To examine the effect of downregulation of the plasminogen activator/plasmin system by alpha2-antiplasmin (alpha2-AP) on cell-cell adhesion mediated by E-cadherin in oral SCC cells, the oral SCC cell line SCCKN was stably transfected with alpha2-AP cDNA. Induction of alpha2-AP expression led to the inhibition of the proteolysis of E-cadherin by plasminogen activator/plasmin in SCC cells, resulting in the enhancement of the cell aggregation and the suppression of the cell motility. Moreover, alpha2-AP also reduced the ability of SCC cells to invade type I collagen gel, and suppressed tumorigenicity in vivo. These results suggested that downregulation of the plasminogen activator/ plasmin system by alpha2-AP might be a potent therapeutic approach to prevent the progression of oral SCC.

Plasminogen activator/plasmin system suppresses cell-cell adhesion of oral squamous cell carcinoma cells via proteolysis of E-cadherin.

The participation of plasminogen activator/plasmin system in the expression and function of E-cadherin was examined in oral squamous cell carcinoma (SCC) cells. Treatment of SCC cells with plasminogen reduced the Ca2+-dependent cell aggregation. SCC cells expressed E-cadherin at the cell membrane, and released a small amount of soluble E-cadherin at 80 kDa in the culture medium. Addition of plasminogen to SCC cells led to a decrease in the amount of E-cadherin of the cell membrane and the enhancement of the shedding of E-cadherin ectodomain. Plasmin directly cleaved E-cadherin of SCC cells and enhanced the motility of SCC cells. These results suggested that plasminogen activator/plasmin system might directly mediate the proteolytic processing of E-cadherin in oral SCC cells and that might facilitate the progression of oral SCC by downregulation of E-cadherin-mediated cell-cell adhesion.

Participation of fibroblasts in MMP-2 binding and activation on the surface of oral squamous cell carcinoma cells.

The effect of fibroblasts on the activation of matrix metalloproteinase-2 (MMP-2) in oral squamous cell carcinoma (SCC) cells was examined. The plasma membrane of SCC cells failed to bind and activate latent MMP-2. However, treatment of SCC cells with fibroblast-conditioned medium (fibroblast-CM) led to the enhancement of the binding and activation of latent MMP-2 on the cell surface. Moreover, fibroblasts induced the expression of membrane type 1 MMP (MT1-MMP) in SCC cells. MMP-2 activated on the cell surface bound to the surface of SCC cells via alphav integrins. These findings suggest that fibroblasts might facilitate the invasion of SCC cells by increasing the proteolytic activity on the surfaces of SCC cells.

Role of stromal thrombospondin-1 in motility and proteolytic activity of oral squamous cell carcinoma cells.

The immunohistochemical localization of thrombospondin-1 (TSP-1) in human normal oral mucosa and oral squamous cell carcinoma (SCC) was examined. The immunostaining of TSP-1 was mainly localized in the connective tissues adjacent to the epithelium of oral mucosa, whereas epithelial cells showed negligible immunoreactivity for TSP-1. TSP-1 expression was striking in the stroma of SCC. TSP-1 synthesis by SCC cells and fibroblasts in culture was examined by immunoprecipitation with anti-TSP-1 antibody. Fibroblasts produced a large amount of TSP-1, whereas SCC cells secreted little amount of TSP-1. Treatment of fibroblasts by the conditioned medium of SCC cells led to an increase in TSP-1 synthesis. TSP-1 induced haptotactic migration and stimulated the production of matrix metalloproteinase-9 (MMP-9) in SCC cells. These results suggest that TSP-1 in the stroma of oral SCC might be synthesized by mesenchymal cells but not by epithelial cells, and that the synthesis of TSP-1 might be regulated by interaction with SCC cells. TSP-1 accumulated in the stroma might promote the progression of oral SCC by enhancing the motility and proteolytic activity in a paracrine manner.

Expression of fibroblast growth factor receptor genes in human hepatoma-derived cell lines.

The fibroblast growth factor (FGF) function has been considered to contribute to various human tumors and malignant growth of neoplasm. Hepatocellular carcinoma (HCC) is a typical hypervascular tumor, and it is suggested that FGF may be involved in hepatocarcinogenesis. Therefore, the relationship between the progression of HCC and expression of FGFs and FGF receptors (FGFRs) was evaluated in this study. We investigated the expression of messenger ribonucleic acids (mRNAs) of FGFs and FGFRs by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis in eight human hepatoma-derived cell lines (Hep3B, HLE, HLF, HUH6, HUH7, KIM1, Li7, and PLC/PRF/5), one hepatoblastoma-derived cell line (HepG2), and human primary hepatocytes. In addition, effects of FGF-1, FGF-2, and FGF-7 on the growth of hepatoma-derived cell lines were studied in serum-free defined culture conditions. An RT-PCR analysis revealed that all cell lines except PLC/PRF/5 expressed all FGFR mRNAs: FGF-R1 (IIIc), -R2 (IIIb), -R2 (IIIc), -R3 (IIIb), -R3 (IIIc), and -R4 mRNAs. In contrast, human primary hepatocytes expressed FGF-R1 (IIIc), -R3 (IIIc), and -R4 mRNAs but not mRNAs of FGF-R2 (IIIb), -R2 (IIIc), and -R3 (IIIb). All cell lines except HUH6 and HUH7 expressed FGF-1 and FGF-2 mRNAs. Addition of exogenous FGF-1 or FGF-2 (or both) to culture stimulated cell proliferation in several cell lines, but FGF-7 exhibited no growth stimulation in all cells. Hepatoma cells may possess a proliferation mechanism regulated by an autocrine mechanism, a paracrine mechanism, or both, which are mediated by FGF-1/FGFR or FGF-2/FGFR (or both). In addition, a gain of FGF-R2 (IIIb), -R2 (IIIc), and -R3 (IIIb) may be associated with malignant transformation of liver tumor and may eventually serve as useful diagnostic and prognostic indicators.

Overexpression of integrin αv facilitates proliferation and invasion of oral squamous cell carcinoma cells via MEK/ERK signaling pathway that is activated by interaction of integrin αvß8 with type â collagen.

To examine the role of integrin αv subunit in the progression of squamous cell carcinoma (SCC), oral SCC cells were stably transfected with integrin αv cDNA. Integrin αv transfectants exhibited the enhancement of proliferation on type Ⅰ collagen, and seemed to have a high ability to invade type Ⅰ collagen gel. Overexpression of integrin αv led to rapid phosphorylation of focal adhesion kinase (FAK), mitogen­activated protein kinase kinase 1/2 (MEK1/2) and extracellular signal­regulated kinase 1/2 (ERK1/2) in SCC cells on type Ⅰ collagen. The downregulation of integrin ß8 in integrin αv transfectants by its specific antisense oligonucleotide led to a decrease in type Ⅰ collagen­stimulated activation of FAK and the MEK/ERK signaling pathway, and also suppressed the proliferation on type Ⅰ collagen and the invasiveness into type Ⅰ collagen gel. Moreover, the expression of integrin ß8 was induced following transfection with integrin αv cDNA. These results indicated that the overexpression of integrin αv induces integrin αvß8 heterodimer formation and the binding of integrin αvß8 to type Ⅰ collagen might enhance the proliferation and invasion of SCC cells via the activation of the MEK/ERK signaling pathway.

Ectomesenchymal chondromyxoid tumor of the tongue: insights on histogenesis.

OBJECTIVE: The objective of this study was to investigate the histogenesis of ectomesenchymal chondromyxoid tumors (ECTs) of the tongue. STUDY DESIGN: The biochemical characteristics of a rarely occurring tumor of the tongue were analyzed by immunohistochemistry and reverse-transcriptase polymerase chain reaction (RT-PCR), and its biological properties were assessed in primary culture in serum-free media. RESULTS: Immunohistochemistry showed that the tumor cells were strongly positive for vimentin, S-100, and glial fibrillary acidic protein (GFAP), but negative for cytokeratin and epithelial membrane antigen. In primary cultures, the cells derived from the ECT were morphologically similar to neuronal cells and expressed Nanog, GFAP, and MAP2. RT-PCR analysis of the surgical specimen was positive for OCT3/4, Sox2, Nanog, MAP2, and CD105 mRNAs. CONCLUSIONS: The results of the present study indicate that ECTs originate from the ectomesenchymal cells of the neural crest and are similar in their molecular and biological characteristics to undifferentiated mesenchymal stem cells.

Constitutive activating mutation of the FGFR3b in oral squamous cell carcinomas.

A G to T mutation at nucleotide position 2128 in the human FGFR3b coding region resulting in a Cys for Gly substitution (G697C) in the tyrosine kinase domain was observed in 62% (44/71) of oral squamous cell carcinomas (OSCC) examined. Immunostained FGFR3b was found in the cytoplasm of prickle cells in normal epithelia, and FGFR3b was localized in the cytoplasm and nucleus in non-FGFR3b mutant OSCC. Overexpressed FGFR3b protein on plasma membranes was noted in OSCC bearing the FGFR3b mutation. Enhanced tyrosine kinase activity of G697CFGFR3b was confirmed. Our results indicate that G697C is an activating mutation causing constitutive ligand-independent FGFR3b signaling. This mutation may be involved in the progression of OSCC and thus the FGFR3b coding sequence may have diagnostic or prognostic value for OSCC.