Sayaka Inoue

The expression profile of filaggrin-2 in the normal and pathologic human oral mucosa

The epithelial cells of the oral cavity show a remarkable degree of regional variation with respect to their morphology and keratinization status. In the oral cavity, the tongue and palate contain keratinizing stratified epithelia, while the buccal mucosa contains non-keratinizing stratified epithelia. We herein examined the expression of filaggrin-2, a member of the S100 fused-type protein family, in the oral mucosa. Filaggrin-2 was weakly expressed in the normal epithelium of the palate, but not in the buccal mucosa or tongue, although filaggrin protein was observed in the epithelium of the buccal mucosa and the palate. We next examined the expression of filaggrin-2 in the oral mucosa of subjects with hyperkeratotic diseases. The expression of filaggrin-2 was markedly increased in the epithelium of the oral mucosa in patients with lichen planus, leukokeratosis and leukoplakia. Filaggrin-2 positivity was observed in granules, some of which were co-localized with those of filaggrin. These results indicate that filaggrin-2 was expressed in the oral mucosa under certain pathological conditions, demonstrating that an aberrant protein expression, together with filaggrin, indicates the altered differentiation program including hyperkeratosis that occurs in these diseases.

In vitro synergistic effects of zoledronic acid and calcium on viability of human epithelial cells

OBJECTIVE Bisphosphonate-related osteonecrosis of the jaw is a common complication with defective wound healing of oral mucosa and frequently occurs in patients receiving zoledronic acid (ZA). The aim of this in vitro study was to investigate whether ZA has a cytotoxic effect at clinically relevant concentrations on epithelial cells when calcium conditions are altered. METHODS HaCaT human keratinocyte cells were treated with ZA in the presence of various concentrations of calcium. The concentrations of ZA included submicromolar ones, which are comparable with those found in the plasma of patients. Cell viability and apoptosis were assessed using MTT assay and annexin V flow cytometry. RESULTS Under standard culture conditions, cell growth was inhibited at 1 μM of ZA or above, but was unaffected by lower concentrations. However, when calcium concentrations were moderately increased, cell viability was decreased and apoptosis was induced at 0.2-0.3 μM of ZA. Moreover, a 50% reduction in serum in the hypercalcemic medium resulted in a significant decrease in cell viability at a much lower concentration (0.05 μM). CONCLUSION These results suggest that clinically relevant concentrations of ZA, which alone have little effects, can be toxic to the epithelial cells depending on the conditions of extracellular calcium.

Extracellular Ca2+-dependent enhancement of cytocidal potency of zoledronic acid in human oral cancer cells

Direct antitumor effects of bisphosphonates (BPs) have been demonstrated in various cancer cells in vitro. However, the effective concentrations of BPs are typically much higher than their clinically relevant concentrations. Oral cancers frequently invade jawbone and may lead to the release of Ca(2+) in primary lesions. We investigated the effects of the combined application of zoledronic acid (ZA) and Ca(2+) on proliferation and apoptosis of oral cancer cells. Human oral cancer cells, breast cancer cells, and colon cancer cells were treated with ZA at a wide range of concentrations in different Ca(2+) concentration environments. Under a standard Ca(2+) concentration (0.6mM), micromolar concentrations of ZA were required to inhibit oral cancer cell proliferation. Increasing extracellular Ca(2+) concentrations greatly enhanced the potency of the ZA cytocidal effect. The ability of Ca(2+) to enhance the cytocidal effects of ZA was negated by the Ca(2+)-selective chelator EGTA. In contrast, the cytocidal effect of ZA was less pronounced in breast and colon cancer cells regardless of whether extracellular Ca(2+) was elevated. In oral cancer cells incubated with 1.6mM Ca(2+), ZA up-regulated mitochondrial Bax expression and increased mitochondrial Ca(2+) uptake. This was associated with decreased mitochondrial membrane potential and increased release of cytochrome c. We suggest that ZA can specifically produce potent cytocidal activity in oral cancer cells in an extracellular Ca(2+)-dependent manner, implying that BPs may be useful for treatment of oral squamous cell carcinoma with jawbone invasion leading to the hypercalcemic state.

Mucosa-associated Lymphoid Tissue Lymphoma of the Palate

Abstract This report is of a 60-year-old woman with mucosa-associated lymphoid tissue lymphoma of the palate. A moderate dose of radiotherapy and anti-CD20 monoclonal antibody chemotherapy were administered after tumour resection. There was no sign of recurrence 14 months after treatment.

Frey's Syndrome after Surgery for Fracture of the Mandibular Condyle

Abstract This report is of a 55-year-old woman presenting with Freys syndrome 6 months after surgical fixation of a fracture of the mandibular condyle. Treatment consisted of a fascia lata graft placed under the involved skin. No recurrence of gustatory sweating was observed.