[Oral management for cancer patients]

Chemotherapy and radiotherapy administered to cancer patients can be harmful because of their effect on normal cells as well as cancer cells, and cause many adverse events. The oral cavity is one of the sites most vulnerable to the direct and indirect effects of cancer therapy. Severe adverse events of the oral cavity can not only reduce a patient's QOL, but also disrupt cancer treatment. We discuss the concept of oral management by maintenance of the oral environment.

Effect of a nitric oxide synthase inhibitor and a CXC chemokine receptor-4 antagonist on tumor growth and metastasis in a xenotransplanted mouse model of adenoid cystic carcinoma of the oral floor

Nitric oxide (NO) is related to angiogenesis and tumor progression and chemokine receptor-4 (CXCR4) plays a central role in cell migration in metastasis and dissemination of cancer. The present study evaluated the effectiveness of a NOS inhibitor and a CXCR4 antagonist, given as single agents or in combination, in a xenotransplanted mouse model of adenoid cystic carcinoma (ACC) of the oral floor. A metastatic tumor (ACCIM) derived from a cervical metastatic lesion of human ACC that was transplantable in nude mice was used. ACCIM showed a high frequency of spontaneous metastasis to the lung when transplanted subcutaneously in nude mice. Mice with subcutaneous transplants of ACCIM were subdivided into six groups and intraperitoneally received one of the following treatments daily for 5 weeks: a) PBS (control), b) AMD3100 (CXCR4 antagonist), c) L-NAME (NOS inhibitor), d) 1400W (iNOS inhibitor), e) both AMD3100 and L-NAME (AMD3100+L-NAME) and f) both AMD3100 and 1400W (AMD3100+1400W). Tumor growth was evaluated during treatment and metastasis was assessed at 28 weeks. Single-agent treatment with AMD3100, L-NAME or 1400W inhibited tumor growth by 20.8, 26.5 and 54.5%, respectively. Combined treatment with AMD3100+L-NAME and AMD3100+1400W inhibited tumor growth remarkably by 48.0 and 50.2%, respectively. Immunohistochemical analysis revealed lower expression of CXCR4, iNOS and eNOS in tumor cells treated with AMD3100+L-NAME or AMD3100+1400W compared to control tumor cells and increased numbers of apoptotic tumor cells were demonstrated using the TUNEL method. CXCR4 expression decreased in 1400W-treated tumors using western blot analysis. When the effect of each agent on tumor-induced angiogenesis in tumor stroma was examined histologically, microvessel density was significantly lower in the groups treated with 1400W, AMD3100+L-NAME or AMD3100+1400W compared to the control, AMD3100 and L-NAME groups. Moreover, treatment with AMD3100 or 1400W markedly inhibited lung metastasis. Our results indicated that single-agent treatment with 1400W and combined treatment with AMD3100+L-NAME or AMD3100+1400W induced apoptosis and significantly inhibited tumor-induced angiogenesis and proliferation of ACCIM in vivo. Blockade of CXCR4 and iNOS was suggested to inhibit lung metastases from ACCIM. CXCR4 and iNOS may, thus, be important prognostic factors for long-term survival in ACC.

[Assessment of oral health using the general oral health assessment index in patients with overactive bladder]

Patients administered anti-cholinergic agents, as first-line therapy for an overactive bladder (OAB) are often unable to continue medical treatment because of dry mouth. We assessed oral health in patients with OAB using the General Oral Health Assessment Index (GOHAI), an oral health-related quality of life questionnaire. We investigated 75 patients with OAB who were receiving continuous administration of anti-cholinergic agents. The OAB symptom score, as well as GOHAI and our original dry mouse score were determined by self-administered questionnaires. The mean age of the subjects was 70.9±10.2 years, the median period of anti-cholinergic agent use was 20 (1-116) months and the mean OAB symptom score was 6.3±3.1. The GOHAI score for all patients was 51.9±8.4 and not significantly different from the national normal value (p＝0.22). On the other hand, the score in patients with a severely dry mouth was 49.2±8.6, which was worse than the national normal value (p＝0.04). The psychosocial functioning score in patients with a severely dry mouth was significantly lower than in those with a slightly dry mouth (p＝0.02). Our results indicate that dry mouth in patients with OAB is significantly associated with worsening of oral health. GOHAI is useful as a screening test to assess the quality of life in patients with OAB.

SATB1 collaborates with loss of p16 in cellular transformation

Tumor progression is associated with invasiveness and metastatic potential. The special AT-rich binding protein 1 (SATB1) has been identified as a key factor in the progression of breast cancer cells to a malignant phenotype and is associated with progression of human tumors. In normal development, SATB1 coordinates gene expression of progenitor cells by functioning as a genome organizer. In contrast to progenitor and tumor cells, SATB1 expression in nontransformed cells is not compatible with proliferation. Here we show that SATB1 expression in mouse embryonic fibroblasts induces cell cycle arrest and senescence that is associated with elevated p16 protein levels. Deletion of p16 overcomes the SATB1-induced senescence. We further provide evidence for an interaction of SATB1 with the retinoblastoma (RB)/E2F pathway downstream of p16. A combined deletion of the RB proteins, RB, p107 and p130 (triple-mutant; TM), prevents SATB1-induced G1 arrest, which is restored upon the reintroduction of RB into SATB1-expressing TM fibroblasts. SATB1 interacts with the E2F/RB complex and regulates the cyclin E promoter in an E2F-dependent manner. These findings demonstrate that p16 and the RB/E2F pathway are critical for SATB1-induced cell cycle arrest. In the absence of p16, SATB1 causes anchorage-independent growth and invasive phenotype in fibroblasts. Our data illustrate that p16 mutations collaborate with the oncogenic activity of SATB1. Consistent with our finding, a literature survey shows that deletion of p16 is generally associated with SATB1 expressing human cell lines and tumors.

Unicystic ameloblastoma metastasizing to multiple cervical lymph nodes

Ameloblastoma is the most common odontogenic tumor, but the incidence of its metastasis is extremely low. We report a case of unicystic ameloblastoma metastasizing to the cervical lymph nodes. This patient pointed out a radiolucent cystic lesion with impacted wisdom tooth in the left mandibular region, and recieved enucleation of the cystic lesion and removal of the wisdom tooth. Histopathogical diagnosis was unicystic ameloblastoma. Three years later, this patient complained of a swelling in the left submandibular region. A CT scan showed a bilobed cystic mass measuring 30 mm in diameter compressing the submandibular gland, and we performed extirpation of the mass with the submandibular gland and associated lymph nodes. Histologically, the lesion was cystic and lymph follicles were seen in the cyst-like wall. The laminated epithelium of cyst wall was ameloblastomatous epithelium, and two lymph nodes associated with cystic lesion also included ameloblastomatous epithelium. This is the first report of metastasizing unicystic ameloblastoma.

Functional analysis of Zyxin in cell migration and invasive potential of oral squamous cell carcinoma cells

Zyxin is an evolutionarily conserved protein that has been implicated in the regulation of actin assembly and is mainly located at focal adhesions. However, the biological roles of Zyxin in cancer cells are incompletely understood. We analyzed the functions of Zyxin in cell migration and the invasive potential of OSCC. Zyxin expression was examined using eight OSCC cell lines with two different cell morphologies (6 epithelial type and 2 fibroblastic type). To knockdown Zyxin expression, OSCC cells were transfected with Zyxin siRNA and control siRNA. The cell lines were studied by western blot analysis, immunocytochemical analysis and cell migration and invasion assay. Epithelial type OSCC cells showed a high level of E-cadherin expression and a low level of Zyxin expression. N-cadherin as well as Zyxin were strongly expressed in fibroblastic type OSCC cells. Expression levels of LPP and TRIP6, members of the human Zyxin family, did not differ between epithelial type and fibroblastic type. Knockdown of Zyxin expression by siRNA in fibroblastic type OSCC cells was associated with cell morphological changes from spindle (fibroblastic) to polygonal (epithelial) shape and significantly inhibited cell growth as well as cell migration and invasion. Expression levels of Rac1 and Cdc42 were weaker in Zyxin siRNA-treated fibroblastic type OSCC cells than in control siRNA-treated cells, but the expression of RhoA did not differ significantly. Treatment of fibroblastic type OSCC cells with Rac1 inhibitor decreased the expression of Zyxin mRNA and protein. Zyxin is suggested to promote growth, migration and invasiveness of fibroblastic type OSCC cells by upregulating Rac1 and Cdc42.

Diffuse sclerosing osteomyelitis of the mandible successfully treated with pamidronate: a long-term follow-up report

Diffuse sclerosing osteomyelitis of the mandible (DSOM) is an uncommon chronic inflammatory disease of bone that is refractory to conventional treatments, such as antibiotics, nonsteroidal anti-inflammatory drugs, and decortication. We report a case of chronic DSOM of 15 years' duration in a 61-year-old woman that was successfully treated with a single infusion of pamidronate. Persistent, intractable pain resolved 3 days after infusion. Intense accumulation on (99m)Tc scintigraphy decreased 2 months after infusion, and almost disappeared after 3 years. Panoramic radiography demonstrated a clear decrease in pathologic changes, close to that of normal bone architecture, which has not been reported in DSOM treated with bisphosphonates.

Up-regulation of neutrophil gelatinase-associated lipocalin in oral squamous cell carcinoma: relation to cell differentiation

Neutrophil gelatinase-associated lipocalin (NGAL, also known as lipocalin2, LCN2) is a secreted glycoprotein with increased expression in solid tumors. The expression and functions of NGAL in oral cancer, however, remain unclear. We investigated the expression of NGAL in oral cancer tissues and oral cancer cell lines. By immunohistochemical examinations, NGAL expression was strongly up-regulated in well-differentiated OSCC tissues and moderately to weakly up-regulated in moderately to poorly differentiated OSCC tissues. In contrast, NGAL expression was weak or very weak in normal mucosa and leukoplakia. By western blot analysis, NGAL expression levels positively correlated with cell morphology patterns and loss of E-cadherin. In addition, the enzymatic activity of the NGAL/MMP-9 complex significantly correlated with the results obtained by zymographic analysis. In conclusion, NGAL expression is high in well-differentiated cancer, suggesting that NGAL may be a useful diagnostic marker of tumor-cell differentiation.

Novel PTCH1 mutations in Japanese Nevoid basal cell carcinoma syndrome patients: two familial and three sporadic cases including the first Japanese patient with medulloblastoma

Nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is inherited in an autosomal dominant mode, and is characterized by a combination of developmental abnormalities and predisposition to form a variety of tumors. The hedgehog receptor Patched1 (PTCH1) has been identified as the gene mutated in NBCCS. We analyzed PTCH1 in two familial and three sporadic Japanese NBCCS cases, and identified five germline mutations in PTCH1. Two cases have a nonsense mutation (c.3058C>T and c.2760C>A), one a splice site mutation (c.584+2T>G), one a 1 bp insertion (c.2712_2713insA) and one a 1 bp deletion (c.980Gdel). All mutations induce truncation of the PTCH1 protein or could induce nonsense-mediated mRNA decay. The 11-year-old male patient with splice-site mutation (c.584+2T>G) had medulloblastoma (MB) at the age of 1 year. This is the first NBCCS patient with molecularly defined MB in Japan.

Promotion of hematogenous metastatic potentials in human KB carcinoma cells with overexpression of cyclooxygenase-2

To understand the role of cyclooxygenase (COX)-2 in metastatic potential of oral cancer, COX-2 overexpressing KB/COX-2 cells were inoculated orthotopically into the masseter muscle or injected into the left cardiac ventricle of nude mice. KB/COX-2 showed about 4-fold increase of COX-2 protein expression as compared to KB/Neo which was a mock transfected control. In orthotopic inoculation, metastasis to the regional lymph nodes occurred in 2 out of 15 mice, and metastasis to the lung in 3 out of 15 mice. On the other hand, in intra-cardiac injection, hematogenous metastasis to the lung and bone occurred in 8 out of 10 mice in KB/COX-2, but no metastasis occurred except for only one metastasis to the femur bone out of 10 mice in KB/Neo. Treatment of KB/COX-2 with COX-2 small interfering RNA (siRNA) inhibited the colony formation but not cell growth in vitro, and suppressed tumorigenicity and hematogenous metastasis in nude mice. When expression of adhesion molecules such as E-cadherin, alpha-catenin, beta-catenin and CD44 was examined, there was no difference in alpha- and beta-catenin between the cells. However, expression of E-cadherin was detected in KB/Neo, but not in KB/COX-2. In contrast, expression of CD44 was markedly increased in KB/COX-2 as compared to KB/Neo. Treatment with COX-2 siRNA resulted in suppression of CD44 expression and detectable expression of E-cadherin in KB/COX-2. These findings suggested that overexpression of COX-2 increased hematogenous metastasis, at least in KB cells, via down-regulating E-cadherin and up-regulating CD44 expression.

Induction of hypertrophic chondrocyte-like phenotypes by oxidized LDL in cultured bovine articular chondrocytes through increase in oxidative stress

OBJECTIVE

It has been reported that the lectin-like oxidized low-density lipoprotein (Ox-LDL) receptor 1 (LOX-1) is expressed by chondrocytes in osteoarthritis (OA) cartilage and that Ox-LDL binding to LOX-1 increases intracellular oxidative stress in cultured bovine articular chondrocytes (BACs). It was recently demonstrated that reactive oxygen species (ROS) induce hypertrophic differentiation of chondrocytes in the growth plate. It has also been shown that activated chondrocytes in OA have hypertrophic chondrocyte-like phenotypes. The purpose of this study was to determine whether Ox-LDL induces hypertrophic chondrocyte-like phenotypes in BACs.

DESIGN

Changes in type X collagen (COL10) and runt-related transcription factor 2 (Runx2) mRNA expression in BACs after Ox-LDL stimulation were investigated using real-time polymerase chain reaction (PCR). Western blotting and immunofluorescent cell staining were used to investigate changes in protein level. The antioxidant N-acetyl cysteine (NAC) was used to ascertain whether oxidative stress is involved in COL10 and Runx2 expression. We induced LOX-1 knockdown cells using small interfering RNA (siRNA) to examine the receptor specificity of Ox-LDL.

RESULTS

COL10 expression was upregulated by Ox-LDL in a time- and dose-dependent manner. Immunofluorescent staining showed that Ox-LDL increased COL10 production in the extracellular matrix. Ox-LDL-induced upregulation of COL10 was suppressed by pretreatment with NAC and siRNA. Expression of Runx2 was upregulated by Ox-LDL and H(2)O(2), and these effects were suppressed by NAC pretreatment.

CONCLUSION

Ox-LDL binding to LOX-1 induces a hypertrophic chondrocyte-like phenotype through oxidative stress, indicating that Ox-LDL plays a role in the degeneration of cartilage.

Antitumor effects of inhibitors of nitric oxide synthase or cyclooxygenase-2 on human KB carcinoma cells overexpressing COX-2

Inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 are major inflammatory mediators. Nitric oxide (NO) produced by iNOS has been shown to have an important role in carcinogenesis. Recent studies have suggested that COX-2 expression also contributes to carcinogenesis, as well as tumor growth, invasion, and metastasis. COX-2 inhibitors such as celecoxib are widely recognized to have antitumor activity, but can cause adverse effects. We investigated possible relations between COX-2 and NO with the use of a human epidermoid carcinoma cell line, designated KB, in which overexpression of COX-2 protein was induced by gene transfer. We also assessed the possibility of using NOS inhibitor as an antitumor drug. We isolated a COX-2 transfected clone (KB/COX-2) and used a neomycin-transfected clone (KB/neo) as control. NG-nitro-L-arginine-methyl ester (L-NAME) was used as a NOS inhibitor, dihydrochloride (1400W) as an iNOS inhibitor, and celecoxib as a selective COX-2 inhibitor. All agents inhibited the cell growth of both clones to similar extents in a dose-dependent manner. Prostaglandin E2 (PGE2) production and COX-2 expression in KB/COX-2 were inhibited not only by celecoxib, but also by L-NAME and 1400W. The decreases in PGE2 production and COX-2 expression were most prominent with celecoxib and L-NAME. In vivo, L-NAME and celecoxib significantly inhibited the proliferation of KB/COX-2-xenografted tumors. Tumor weight was reduced by L-NAME (60.6% decrease), 1400W (38.0% decrease), and celecoxib (74.5% decrease) as compared with the control after 21 days of treatment. Immunohistochemically, xenografted tumors expressed COX-2, iNOS, and eNOS. Such expression was suppressed by treatment with L-NAME and celecoxib. These results suggest that L-NAME and celecoxib significantly inhibit the proliferation of murine squamous cell carcinoma in vivo. L-NAME as well as celecoxib might thus be useful for the design and development of new antitumor drugs.

Inhibitory effect of sulindac on DMBA-induced hamster cheek pouch carcinogenesis and its derived cell line

In order to investigate the involvement of cyclooxygenase (COX)-2 in oral carcinogenesis and chemoprevention for it, we examined the COX-2 expression during dimethylbenzanthracene (DMBA)-induced hamster cheek pouch carcinogenesis and the inhibitory effect of sulindac, a non-steroidal anti-inflammatory drug (NSAID), on the carcinogenesis and its derived squamous carcinoma cell line HCPC-1. From the beginning of DMBA application, basal diet or diets containing sulindac 200 or 400 ppm were given to hamsters, and observation of tumor development and measurement of body weight were performed. Immunohistochemical analysis revealed that COX-2 expression was increased toward carcinogenesis from epithelial dysplasia to squamous cell carcinoma (SCC). All hamsters developed SCC, but the onset of carcinoma formation was significantly delayed up to 14.8 and 11.8 weeks in the 200 ppm, and 400 ppm sulindac group, respectively, as compared to 8.7 weeks in the control group. In addition, tumor growth was retarded in the group of sulindac treatment, and mean survival time was 23.7 weeks in the control group and 36.3 and 33.8 weeks in the 200 and 400 ppm sulindac group, respectively. Body weight loss was not observed during the experimental period. Histologically, administration of sulindac inhibited angiogenesis in the tumor stroma. Treatment with sulindac sulfide, an active metabolite of sulindac, caused inhibition of cell growth, PGE2 production and VEGF production in HCPC-1 cells in vitro. Expression of COX-2 protein in HCPC-1 cells was also decreased 2-fold by treatment with sulindac sulfide. It was thus indicated that inhibitory effects were partly due to inhibition of tumor angiogenesis by sulindac. These findings suggested the involvement of COX-2 in DMBA-induced hamster cheek pouch carcinogenesis and the chemopreventive potential of sulindac.