Ammonium tetrathiomolybdate enhances the antitumor effect of cisplatin via the suppression of ATPase copper transporting beta in head and neck squamous cell carcinoma

Platinum‑based antitumor agents have been widely used to treat head and neck squamous cell carcinoma (HNSCC) and numerous other malignancies. Cisplatin is the most frequently used platinum‑based antitumor agent, however drug resistance and numerous undesirable side effects limit its clinical efficacy for cancer patients. Cancer cells discharge cisplatin into the extracellular space via copper transporters such as ATPase copper transporting beta (ATP7B) in order to escape from cisplatin‑induced cell death. In the present study, it was demonstrated for the first time that the copper chelator ammonium tetrathiomolybdate (TM) has several promising effects on cisplatin and HNSCC. First, TM suppressed the ATP7B expression in HNSCC cell lines in vitro, thereby enhancing the accumulation and apoptotic effect of cisplatin in the cancer cells. Next, it was revealed that TM enhanced the antitumor effect of cisplatin in HNSCC cell tumor progression in a mouse model of bone invasion, which is important since HNSCC cells frequently invade to facial bone. Finally, it was demonstrated that TM was able to overcome the cisplatin resistance of a human cancer cell line, A431, via ATP7B depression in vitro.

Caries experience and oral health-related quality of life (OHRQoL) of children and adolescents with cerebral palsy in a low-resource setting

Background

Children with complex neurodevelopmental disabilities such as cerebral palsy (CP), have a higher risk of dental disease related at least in part to greater difficulties in performing and maintaining effective oral hygiene and oral care practices. However, to date, there are very few studies that have considered the impact of dental disease on the Oral Health-Related Quality of Life (OHRQoL) of children and adolescents with cerebral palsy. This study aimed to investigate the association between dental caries experience and oral health related quality of life (OHRQoL) among children and adolescents with cerebral palsy in a low-resource setting (Bangladesh).

Methods

A total of 90 children and adolescents with CP, 2–17 years old (median age 10 years; 37.8% female and 62.2% male) were randomly selected from the Bangladesh Cerebral Palsy Register (BCPR) The decayed, missing and filled teeth (dmft/DMFT) index was used to measure caries experience. Child Perceptions Questionnaire (CPQ) and Family Impact Scale (FIS) were used to assess oral health–related quality of life (OHRQoL). Binary logistic regression was used to investigate factors that may contribute to dental caries experience.

Results

Dental caries were observed among 55.6% of the participants. After adjusting for age and gender, binary logistic regression analysis showed that dental caries experience was significantly associated with those who had teeth/mouth pain (rate ratio 7.3; P = 0.02), food caught between teeth (rate ratio: 6.4; P = 0.02), difficulty in eating and drinking (rate ratio 5.9; p = 0.02) and those who felt frequently upset (rate ratio: 54.7; P = 0.02).

Conclusion

In this study, we found that children and adolescents with CP in a low-resource setting had high dental caries experience and that dental caries had a negative impact on OHRQoL amongst these participants and their parents/caregivers. Health care professionals should be aware of the importance of dental health and oral hygiene in this population. These findings highlight the need for oral health promotion programs for children and adolescents with CP in these settings to reduce pain and to improve quality of life.

Ammonium tetrathiomolybdate enhances the antitumor effects of cetuximab via the suppression of osteoclastogenesis in head and neck squamous carcinoma

Head and neck squamous cell carcinoma (HNSCC) poses a significant challenge clinically where one of the mechanisms responsible for the invasion into facial bones occurs via the activation of osteoclasts. Copper has been demonstrated to play a key role in skeletal remodeling. However, the role of copper in cancer-associated bone destruction is thus far unknown. Lysyl oxidase (LOX) is a copper-dependent enzyme that promotes osteoclastogenesis. In the present study, we investigated the effects of copper on HNSCC with bone invasion by the copper chelator, ammonium tetrathiomolybdate (TM) in vitro and in vivo. We demonstrate that TM blocks the proliferation of HNSCC cells, inhibits LOX activation and decreases the expression of the receptor activator of nuclear factor-κB ligand (RANKL) in osteoblasts and osteocytes, subsequently suppressing bone destruction. These findings suggest that copper is a potential target for the treatment of HNSCCs associated with bone destruction.

Semaphorin 4D promotes bone invasion in head and neck squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) frequently invade the bones of the facial skeleton. Semaphorin 4D (Sema4D) is an axon guidance molecule produced by oligodendrocytes. Sema4D was also identified in the bone microenvironment and many cancer tissues including HNSCC. To date, however, the role of Sema4D in cancer-associated bone disease is still unknown. This is the first study to demonstrate the role of Sema4D in bone invasion of cancer. In the clinical tissue samples of bone lesion of HNSCC, Sema4D was detected at high levels, and its expression was correlated with insulin-like growth factor-I (IGF-I) expression. In vitro experiments showed that IGF-I regulates Sema4D expression and Sema4D increased proliferation, migration and invasion in HNSCC cells. Sema4D also regulated the expression of receptor activator of nuclear factor κβ ligand (RANKL) in osteoblasts, and this stimulated osteoclastgenesis. Furthermore, knockdown of Sema4D in HNSCC cells inhibited tumor growth and decreased the number of osteoclasts in a mouse xenograft model. Taken together, IGF-I-driven production of Sema4D in HNSCCs promotes osteoclastogenesis and bone invasion.

DKK3 Overexpression Increases the Malignant Properties of Head and Neck Squamous Cell Carcinoma Cells

DKK3, a member of the dickkopf Wnt signaling pathway inhibitor family, is believed to be a tumor suppressor because of its reduced expression in cancer cells. However, our previous studies have revealed that DKK3 expression is predominantly observed in head and neck/oral squamous cell carcinoma (HNSCC/OSCC). Interestingly, HNSCC/OSCC patients with DKK3 expression showed a high rate of metastasis and poorer survival, and siRNA-mediated knockdown of DKK3 in HNSCC-derived cancer cell lines resulted in reduced cellular migration and invasion. From these data, it was hypothesized that DKK3 might exert an oncogenic function specific to HNSCC. In the present research, the DKK3 overexpression model was established, and its influences were investigated, together with molecular mechanism studies. The DKK3 expression profile in cancer cell lines was investigated, including HNSCC/OSCC, esophageal, gastric, colorectal, pancreatic, prostatic, and lung cancers. DKK3 overexpression was performed in HNSCC-derived cells by transfection of expression plasmid. The effects of DKK3 overexpression were assessed on cellular proliferation, migration, invasion, and in vivo tumor growth. The molecular mechanism of DKK3 overexpression was investigated by Western blotting and microarray analysis. DKK3 overexpression significantly elevated cellular proliferation, migration, and invasion, as well as increased mRNA expression of cyclin D1 and c-myc. However, reporter assays did not show TCF/LEF activation, suggesting that the increased malignant property of cancer cells was not driven by the Wnt/β-catenin pathway. For the investigation of the pathways/molecules in DKK3-mediated signals, the Western blot analyses revealed that phosphorylation of Akt (S473) and c-Jun (Ser63) was elevated. The application of a PI3K kinase inhibitor, LY294002, on HSC-3 DKK3 cells significantly decreased tumor cell proliferation, migration, and invasion. From these results, we demonstrated that DKK3 might contribute to cellular proliferation, invasion, migration, and tumor cell survival in HNSCC cells through a mechanism other than the canonical Wnt signaling pathway, which might be attributed to PI3K–Akt signaling.

Risk factors for dental caries among children with cerebral palsy in a low-resource setting

AIM

To describe the oral health status and investigate factors affecting dental caries experience among children with cerebral palsy (CP) in rural Bangladesh.

METHOD

A cross-sectional study was conducted among children with CP who are part of the Bangladesh Cerebral Palsy Register (BCPR) study. Caries experience was measured by identifying decayed, missing, and filled teeth for deciduous and permanent teeth (dmft/DMFT). Clinical periodontal index, body mass index, oral hygiene behaviour, masticatory ability, and dietary habits were recorded. CP motor types and severity of functional mobility (Gross Motor Function Classification System [GMFCS]) were assessed.

RESULTS

Of 90 children with CP (mean age 9y 7mo, range 2-17y, 37.8% female and 62.2% male), 35% of 2 to 6 year olds, and 70% of 7 to 11 year olds (p=0.014) experienced caries (dmft+DMFT>0). The mean values (standard deviation [SD]) of dmft and DMFT were 2.46 (3.75) and 0.72 (1.79) respectively. After adjusting for age and sex, binary logistic regression analysis showed a significant relationship with dental caries for children who had quadriplegia (odds ratio [OR] 5.56, p=0.035), tooth cleaning less than one time/day (OR 0.08, p=0.016), using toothpowder or charcoal for cleaning (OR 7.63, p=0.015), and snacking between meals more than one time/day (OR 6.93, p=0.012).

INTERPRETATION

Early oral health preventive care is required for children with CP because dental caries is highly prevalent in these children.

Synthetic Terrein Inhibits Progression of Head and Neck Cancer by Suppressing Angiogenin Production

BACKGROUND/AIM

Head and neck cancers are the fifth most common cancer type worldwide, affecting more than half a million patients annually. Development of effective therapeutic drugs is, therefore, required for this type of disease. This study assessed the effects of synthetic terrein on head and neck cancer.

MATERIALS AND METHODS

Synthetic terrein was prepared by using the modified Altenhach's procedure. The effect of synthetic terrein on cell proliferation of head and neck cancer cells and HUVECs was assessed. Angiogenin secretion and ribosome biogenesis were examined by ELISA and silver staining of the nucleolar organizer region. A mouse xenograft model was prepared by inoculating mice with suspensions of cells of the human head and neck cancer cell line OSC-19 subcutaneously into the dorsal region of each mouse. Ki-67, CD31 and angiogenin expression in xenografted tumors was examined by immunohistochemistry.

RESULTS

Synthetic terrein inhibited the growth of various head and neck cancer cells. In addition, an in vivo experiment revealed that synthetic terrein inhibited a xenograft tumor growth in athymic mice. Immunohistochemical analysis revealed that expression of Ki-67, CD31 and ANG was down-regulated in synthetic terrein-treated tumors, compared to controls. Synthetic terrein suppressed the ANG secretion and ribosome biogenesis in cancer cells, and cell proliferation in vascular endothelial cells.

CONCLUSION

The mechanism underlying the anti-tumor effects of synthetic terrein against head and neck cancer consists of the inhibition of both tumor cell proliferation and angiogenesis via the suppression of ANG production.

Brm inhibits the proliferative response of keratinocytes and corneal epithelial cells to ultraviolet radiation-induced damage

Ultraviolet radiation (UV) from sunlight is the primary cause of skin and ocular neoplasia. Brahma (BRM) is part of the SWI/SNF chromatin remodeling complex. It provides energy for rearrangement of chromatin structure. Previously we have found that human skin tumours have a hotspot mutation in BRM and that protein levels are substantially reduced. Brm−/− mice have enhanced susceptibility to photocarcinogenesis. In these experiments, Brm−/− mice, with both or a single Trp53 allele were exposed to UV for 2 or 25 weeks. In wild type mice the central cornea and stroma became atrophic with increasing time of exposure while the peripheral regions became hyperplastic, presumably as a reparative process. Brm−/−, Trp53+/−, and particularly the Brm−/− Trp53+/− mice had an exaggerated hyperplastic regeneration response in the corneal epithelium and stroma so that the central epithelial atrophy or stromal loss was reduced. UV induced hyperplasia of the epidermis and corneal epithelium, with an increase in the number of dividing cells as determined by Ki-67 expression. This response was considerably greater in both the Brm−/− Trp53+/+ and Brm−/− Trp53+/− mice indicating that Brm protects from UV-induced enhancement of cell division, even with loss of one Trp53 allele. Cell division was disorganized in Brm−/− mice. Rather than being restricted to the basement membrane region, dividing cells were also present in the suprabasal regions of both tissues. Brm appears to be a tumour suppressor gene that protects from skin and ocular photocarcinogenesis. These studies indicate that Brm protects from UV-induced hyperplastic growth in both cutaneous and corneal keratinocytes, which may contribute to the ability of Brm to protect from photocarcinogenesis.

Novel HSP90 inhibitor NVP-AUY922 enhances the anti-tumor effect of temsirolimus against oral squamous cell carcinoma

BACKGROUND AND AIM

Heat shock protein 90 (HSP90) and mammalian target of rapamycin (mTOR) are involved in the molecular pathogenesis of advanced oral squamous cell carcinoma. HSP90 inhibitors are capable of effectively interfering with multiple signaling pathways, including the mTOR signaling pathway. However, the combined effects of HSP90 and mTOR inhibitors on oral squamous cell carcinoma are still unknown. In this study, we investigated the dual treatment of the novel HSP90 inhibitor NVP-AUY922 and temsirolimus against oral squamous cell carcinoma.

MATERIALS AND METHODS

The effect of the combination of NVP-AUY922 and temsirolimus on oral squamous cell carcinoma in vitro and in vivo was determined by MTS assay and mouse xenograft models. The effect of the combination on angiogenesis was determined by tube formation assay and angioreactor.

RESULTS

The combination treatment of NVP-AUY922 and temsirolimus significantly inhibited the proliferation of SAS oral squamous cell carcinoma cells in vitro and suppressed the growth of oral squamous cell carcinoma xenografts in vivo. We have clearly shown that the combination treatment of NVP-AUY922 and temsirolimus inhibited vascular formation both in vitro and in vivo. Moreover, the combination treatment of NVP-AUY922 and temsirolimus prolonged the survival rate in mice xenografted with oral squamous cell carcinoma.

CONCLUSIONS

Here, we showed the activity of a combination of mTOR and HSP90 inhibitors for the treatment of advanced oral squamous carcinoma.

Anti-tumor effect of a novel FAK inhibitor TAE226 against human oral squamous cell carcinoma

OBJECTIVES

Focal adhesion kinase (FAK) overexpression is frequently found in invasive and metastatic cancers, but its role in oral squamous cell carcinoma is not yet well understood. In order to seek therapies targeting oral squamous cell carcinoma, we developed the novel FAK Tyr(397) inhibitor TAE226 and investigated its anti-tumor effects and mechanisms.

MATERIALS AND METHODS

Expression of phosphorylated FAK Tyr(397) was examined by immunohistochemical and immunoblot analysis. The effect of TAE226 on in vitro and in vivo studies were confirmed by proliferation, cell cycle, apoptosis and angiogenesis analysis.

RESULTS

We found that phosphorylated FAK was highly expressed in human tongue oral squamous cell carcinoma in patients. Importantly, TAE226 greatly suppressed the proliferation, migration and invasion of human oral squamous cell carcinoma SAS cells with an apparent structural change of actin fiber and a loss of cell adhesion. In addition, TAE226 inhibited the expression of phospho-FAK Tyr(397) and phospho AKT Ser(473), resulting in caspase-mediated apoptosis. Furthermore, oral administration of TAE226 in mice suppressed the growth and angiogenesis of oral squamous cell carcinoma xenografts in vivo.

CONCLUSIONS

Our results provide compelling evidence that FAK is critically involved in oral squamous cell carcinoma and that the FAK inhibitor TAE226 can potentially be effectively used for the treatment of oral squamous cell carcinoma.

Mutant p53 R248Q but not R248W enhances in vitro invasiveness of human lung cancer NCI-H1299 cells

More than half of all human cancers are associated with mutations of the TP53 gene. In regard to the functional interaction with the remaining wild-type (WT) p53 allele, p53 mutations are classified into two types, recessive and dominant-negative (DN) mutations. The latter mutant protein has a DN activity over the remaining WT allele. We previously showed that the DN p53 mutant was useful as a predictor of poor outcome or a risk factor for metastatic recurrence in patients with some types of cancers, regardless of the presence or absence of loss of heterozygosity (LOH) of WT p53, suggesting that the DN p53 had 'gain-of-function (GOF)' activity besides the transdominance function. In this study, we investigated GOF activity of two DN p53 mutants which had a point mutation at codon 248 (R248Q and R248W), one of the hot spots, by transfecting them respectively into H1299 cells which originally expressed no p53 protein. Growth activity of the transfectants with the two mutants was not different from that of parent or Mock transfectants. Meanwhile, in vitro invasions of Matrigel and type I collagen gel by R248Q-transfectants were significantly higher than those by R248W-transfectants or the control cells. However, there were no differences in cell motile activities, expressions of extracellular matrix-degradative enzymes such as matrix metalloproteinases, urokinase-type plasminogen activator and heparanase, and their inhibitors, between R248Q- and R248W-transfectants. These findings indicate that the p53 mutants have a different quality in GOF activities even if the mutations occurred at the same codon. And detailed information of the status of p53, including transdominancy and GOF activity, is expected to be useful for diagnosis and therapeutic strategy fitting the individual patients.

Induction of MMP-13 expression in bone-metastasizing cancer cells by type I collagen through integrin α1β1 and α2β1-p38 MAPK signaling

BACKGROUND

Breast cancer cells frequently metastasize to the skeleton and produce and secrete proteinases, such as matrix metalloproteinase-13 (MMP-13), which promote destruction of the bone matrix. However, the mechanism of MMP-13 expression induced in areas of bone metastasis is unknown. Here, the interaction between tumors and type I collagen in bone metastasis was investigated.

MATERIALS AND METHODS

A mouse model of bone metastasis was prepared by inoculating mice with suspensions of cells of the human metastatic breast cancer cell line MDA-MB-231 via the left cardiac ventricle. MMP-13 expression was examined by immunohistochemical, Western blot, and real-time RT-PCR analyses.

RESULTS

MMP-13 expression was highly up-regulated in MDA-MB-231 cells, and attachment of these cells to type I collagen and the induction of MMP-13 were down-regulated by treatment with integrin α1, α2 or β1 neutralizing antibodies. The attachment of MDA-MB-231 cells to type I collagen induced the activation of focal adhesion kinase (FAK) and p38 mitogen-activated protein kinase (MAPK). Inhibition of FAK and p38 MAPK down-regulated type I collagen-induced MMP-13 expression.

CONCLUSION

Our study indicates that metastatic breast cancer cells in the bone microenvironment attached to type I collagen, which stimulated integrins α1β1 and α2β1, via FAK and p38 MAPK pathways, to induce MMP13 expression and further osteolysis.

Antitumor effect of novel HSP90 inhibitor NVP-AUY922 against oral squamous cell carcinoma

Heat-shock protein 90 (HSP90) is a major cellular chaperone protein. HSP90 supports the correct conformation, stabilization, activation, and localization of 'client' oncoproteins, many of which are involved in tumor progression. Therefore, the use of HSP90 inhibitors has become a new strategy in antitumor therapy. However, the effects of an HSP90 inhibitor on oral squamous cell carcinoma are still unclear. NVP-AUY922 (Novartis) is a novel 4,5-diaryloxazole adenosine triphosphate-binding site HSP90 inhibitor. In this study, we investigated the antitumor effect of novel HSP90 inhibitor NVP-AUY922 against oral squamous cell carcinoma. NVP-AUY922 inhibited the proliferation of oral squamous cell carcinoma cells in vitro. NVP-AUY922 caused degradation of client protein inducing ErbB2, p-Akt, p-S6, hypoxia-inducible factor 1-α (HIF1-α) and vascular endothelial growth factor (VEGF) and up-regulation of HSP70 in HSC-2 oral squamous cell carcinoma. NVP-AUY922 increased the expression of cleaved caspase-3 and induced apoptosis in HSC-2 cells. Treatment of NVP-AUY922 induced a robust antitumor response and suppressed p-Akt and VEGF expression in an HSC-2 xenograft model. In summary, NVP-AUY922 exhibits in vitro and in vivo efficiency against oral squamous cell carcinoma, representing a promising therapeutic approach for oral squamous cell carcinoma.

Increased expression of the PRL-3 gene in human oral squamous cell carcinoma and dysplasia tissues

Phosphatase of regenerating liver (PRL) belongs to a class of the protein tyrosine phosphatase family, which is known so far to consist of 3 members, PRL-1, PRL-2, and PRL-3. The aim of this study was to uncover the role of PRL genes in development of oral malignancy. We analyzed expression levels of the 3 PRL genes in 50 human oral squamous cell carcinomas (OSCCs), 11 dysplasia and 12 normal mucosa tissues by a real-time RT-PCR method. PRL-3 but not PRL-1 or PRL-2 expressions were significantly higher in OSCC and dysplasia than in normal mucosa tissues. Additionally, PRL-3 expressions were significantly higher in OSCC tissues harboring dominant-negative p53 or recessive p53 mutation than in those harboring wild-type p53. These results suggest that PRL-3 plays a role in oral cancer development and can be useful as a marker of pre-malignant and malignant lesion of oral mucosa.

Parathyroid hormone-related peptide regulates matrix metalloproteinase-13 gene expression in bone metastatic breast cancer cells

BACKGROUND

Breast cancer (BC) cells often metastasize to bone where they express large amounts of parathyroid hormone-related protein (PTHrP). In this study, we investigated the possibility that PTHrP may have roles in breast cancer bone metastasis independently of, or in addition to, its roles in osteoclastic function.

MATERIALS AND METHODS

A mouse model of bone metastasis was prepared by inoculating mice with suspensions of the human BC cell line MDA-MB-231 tumor cells via the left cardiac ventricle. Matrix metalloproteinase-13 (MMP-13) expression in the bone microenvironment was examined by Western blot and Real-time RT-PCR (RT-PCR) analysis, as well as by confocal microscopy.

RESULTS

The invading MDA-MB-231 cells contained conspicuous amounts of both PTHrP and MMP-13, an important matrix-degrading enzyme; and treatment of the cells in culture with exogenous PTHrP markedly stimulated MMP13 gene expression. Analysis of signaling mechanisms showed that PTHrP treatment led to rapid increases in the levels of phosphorylated protein kinase C (PKCα) and extracellular signal-regulated kinase (ERK1/2). Pharmacologic inhibition of ERK1/2 and PKC as well as of PKA activities counteracted the PTHrP-dependent stimulation of MMP13 expression. Indeed, pharmacologic activation of PKA or PKC was sufficient for stimulation of MMP13 expression.

CONCLUSION

Consistent with these findings, the inhibition of PKC prevented PTHrP-induced activation of ERK1/2, whereas 12-O-tetradecanoylphorbol-13-acetate (TPA), a stimulator of PKC, up-regulated the PTHrP-induced activation of ERK1/2. Taken together, our data indicate that the MDA-MB-231 breast cancer cells may carry out bone destruction and favor their own metastatic behavior by producing MMP-13. Given that the cells expressed PTHrP and that this factor stimulated MMP-13 expression, metastatic bone destruction may result from a PTHrP autocrine loop involving a PKC-ERK1/2 signaling pathway.

A multiple primary carcinoma consisting of leukoplakia and SCC: a case report with p53 mutation analysis

Patients with an oral squamous cell carcinoma (OSCC) often develop multiple malignant lesions. This report examined whether individual tumours developed in a patient show the same genetic alteration, such as p53 mutations. This case study describes three SCCs and three leukoplakias which developed simultaneously in a single 67-year-old Japanese man. A p53 mutation was detected in two of the three SCCs and one of the three leukoplakias. One SCC had a missense mutation at codon 285 (GAG>AAG, Glu>Lys) and the other a nonsense mutation at codon 336, and the leukoplakia had a missense mutation at codon 273 (CGT>CAT, Arg>His). This case showed that individual oral tumours may have different genetic changes even when they develop in a single patient. Therefore, this report provided strong evidence that in cases of multiple tumours it is necessary to design tailor-made therapies for each individual tumour rather than a single standardised therapy for all multiple tumours.

Bone destruction by invading oral squamous carcinoma cells mediated by the transforming growth factor-beta signalling pathway

BACKGROUND

Gingival squamous cell carcinoma (SCC) cells frequently invade mandibular bone, and this destruction is associated with a worse prognosis. However, the relationship between bone destruction and associated factors is unclear. In this study, the role and diagnostic utility of transforming growth factor-beta (TGF-beta) type I receptor (TbetaRI) in bone destruction of the mandible was investigated.

PATIENTS AND METHODS

The expression of TbetaRI was explored by using an immunohistochemical method on paraffin-embedded tissues from 21 cases of mandibular SCC. An inhibitor of the kinase activity of the TbetaRI (TbetaRI-I) was used to assess the role of TbetaRI in bone destruction by a human oral SCC cell line (HSC-2) that highly expresses TbetaRI.

RESULTS

TbetaRI-positive signals were closely associated with destructive invasion of the mandible by oral SCC cells. Consistent with these results, TbetaRI-I greatly reduced HSC-2 cell-induced bone destruction and osteoclast formation in vivo and in vitro. TbetaRI-I treatment reduced the expression of TNF-alpha, RANKL and connective tissue growth factor (CTGF/CCN2), all of which were up-regulated by TGF-beta in HSC-2 cells.

CONCLUSION

These data demonstrated an important role for TGF-beta signalling in bone invasion by oral SCC cells, and suggest that the bone destruction is mediated by RANKL, TNF-alpha and CCN2.

PTHrP regulates angiogenesis and bone resorption via VEGF expression

BACKGROUND

Parathyroid hormone-related protein (PTHrP) is a key regulator of osteolytic metastasis of breast cancer (BC) cells, but its targets and mechanisms of action are not fully understood. This study investigated whether/how PTHrP (1-34) signaling regulates expression of vascular endothelial growth factor (VEGF) produced by BC cells.

MATERIALS AND METHODS

A mouse model of bone metastasis was prepared by inoculating mice with tumour cell suspensions of the human BC cell line MDA-MB-231 via the left cardiac ventricle. VEGF expression was examined by Western blot and real-time RT-PCR analysis, as well as by confocal microscopy in the bone microenvironment.

RESULTS

PTHrP was expressed in cancer cells producing PTH/PTHrP receptor and VEGF that had invaded the bone marrow, and PTHrP was up-regulated VEGF in MDA-MB-231 in vitro. The culture medium conditioned by PTHrP-treated MDA-MB-231 cells stimulated angiogenesis and osteoclastogenesis compared with control medium, giving a response that was inhibited by VEGF-neutralizing antibody treatment. Inhibition of protein kinase C (PKC) prevented PTHrP-induced extracellular signal-regulated kinase (ERK1/2) and p38 activation, and PTHrP-induced VEGF expression.

CONCLUSION

PTHrP plays an important role in modulating the angiogenic and bone osteolytic actions of VEGF through PKC-dependent activation of an ERK1/2 and p38 signaling pathway during bone metastasis by breast cancer cells.

The relationship between jaw injury, third molar removal, and orthodontic treatment and TMD symptoms in university students in Japan

AIMS

To determine the association between temporomandibular disorders (TMD) and experiences of jaw injury, third molar removal, and orthodontic treatment, controlling for confounding factors such as age, sex, emotional stress, and oral parafunction.

METHODS

First-year university students (n = 2,374) were instructed to answer a questionnaire regarding symptoms of TMD, jaw injury, third molar removal, orthodontic treatment, stress, and parafunctional habits. All subjects were classified according to the level of TMD symptoms. Logistic regression was applied to assess the associations of experiences of jaw injury, third molar removal, and orthodontic treatment with presence of TMD symptoms after controlling for age, sex, stress, and parafunctional habits.

RESULTS

Of the 2,374 students, 715 students were TMD symptom-positive. They were classified into 7 groups consisting of those with only clicking (group 1), only pain in the temporomandibular joint (group 2), only difficulty in mouth opening (group 3), clicking and pain (group 4), clicking and difficulty in mouth opening (group 5), difficulty in mouth opening and pain (group 6), and all 3 symptoms (group 7). TMD symptoms were significantly associated with jaw injury. Odds ratios were 2.25, 2.47, 3.38, and 2.01 for groups 2, 3, 6, and 7, respectively. Experience of third molar removal was significantly associated with TMD (odds ratio = 1.81 for group 1). No association was found between orthodontic experience and TMD.

CONCLUSION

Experiences of jaw injury and third molar removal might be cumulative and precipitating events in TMD.

Risk indicators for tooth loss due to caries and periodontal disease in recipients of free dental treatment in an adult population in Bangladesh

PURPOSE

The aims of this study were first to identify the risk indicators for permanent tooth extraction in patients who were receiving free dental treatment, and second to determine whether or not the reasons for tooth extraction are related to socio-demographic factors.

MATERIALS AND METHODS

Bangladeshi adults who visited Dhaka Dental College Hospital participated in this study. For each extraction, the clinician recorded age, sex, educational status, type of tooth extracted, dietary habits, oral hygiene, history of smoking and betel quid chewing and reasons for tooth extraction. A series of bivariate analyses and logistic regression analyses were carried out to assess the effects of major variables.

RESULTS

A total of 868 teeth were extracted from 582 patients. Among them, 586 (67.5%) of the teeth were extracted due to caries and its sequelae, 161 (18.5%) and 121 (13.9%) were extracted for periodontal and other reasons. Logistic regression analysis revealed that tooth extraction due to caries had significant associations with age (P = 0.0001), tooth type (P = 0.013), consumption of sweets, snacks and soft drinks (P = 0.0001 and P = 0.0001, respectively), frequency of teeth cleaning (P = 0.007) and dental attendance pattern (P = 0.004). For tooth extraction due to periodontal disease, associations with age (P = 0.001), educational level (P = 0.018), tooth type (P = 0.024), betel quid chewing (P = 0.0001), smoking habit (P = 0.032), method of teeth cleaning (P = 0.001) and the use of dentifrices (P = 0.024) were statistically significant.

CONCLUSIONS

In this group of patients, caries and its sequelae were the most common reasons for extraction of teeth, followed by periodontal disease. Betel quid chewing, smoking and dietary and oral hygiene habits were also significant predictors of tooth loss.

Relationship between betel quid additives and established periodontitis among Bangladeshi subjects

AIM

To determine the relationship between betel quid chewing additives and established periodontitis in Bangladeshi subjects.

MATERIAL AND METHODS

A total of 864 subjects participated in this study. Among them, 140 pairs of sex- and age-matched case subjects and control subjects were selected. A case was defined as a person who had at least two sites with a clinical attachment level (CAL)> or =6 mm and at least one site with probing depth (PD)> or =5 mm. Subjects who did not fulfill these criteria were considered as controls. Information on sociodemographic variables, psychological stress, dental health behaviour, smoking and betel quid chewing habits was obtained.

RESULTS

Multiple logistic regression analysis showed that current betel quid chewers had greater probabilities of having established periodontal disease than did non-chewers (odds ratio=3.97, p<0.05). Mean PD, mean CAL, mean percentage of bleeding on probing and number of missing teeth were significantly higher in chewers of betel quid with tobacco and masala than in chewers of betel quid without such additives adjusting for age, sex, smoking habit, body mass index, dental visit pattern, stress and plaque index. Higher frequency and longer duration of betel quid chewing showed a significant relation to an increase in periodontal parameters.

CONCLUSION

The results indicate that betel quid additives might significantly enhance periodontitis in the population studied.

Aberrant expression of HOX genes in oral dysplasia and squamous cell carcinoma tissues

Human HOX genes consist of 39 genes and encode transcription factors that function as master developmental regulators. We hypothesized that the misexpression of HOX genes was associated with carcinogenesis and malignant progression. The expression levels of 39 HOX genes in 31 human oral squamous cell carcinoma (SCC), 11 dysplasia, and 10 normal mucosa tissues were quantified by the real-time RT-PCR method. The expression levels of 18 HOX genes in the SCC tissues were significantly higher than those in the normal mucosa tissues. The dysplasia tissues showed higher expression of HOXA2, A3, B3, and D10 than normal mucosa tissues whereas they showed lower expression of HOXA1, B7, B9, and C8 than SCC. The SCC with lymph node metastasis showed high expression of HOXC6 compared to the SCC without it. These results suggest that misexpressions of particular HOX genes are implicated in the development of oral dysplasia and SCC.

Association of dietary habits with symptoms of temporomandibular disorders in Bangladeshi adolescents

The prevalences of signs and symptoms of temporomandibular disorder (TMD) in Bangladeshi adolescents and their associations with intake of various hard food items were investigated. A group of 1200 randomly selected high school students aged 12-17 years from three communities (rural, semi-urban and urban) completed a questionnaire on dietary habits and presence of TMD symptoms and were examined clinically. In bivariate analysis, no significant relationship was observed between TMD symptoms and eating of hard foods. However, in logistic regression analysis, clicking showed a significant correlation with consumption of hard vegetable and fruits more than three times per week (P < 0.05). A statistically significant correlation was also observed between consumption of all hard food items (at least one item in each of the four categories of hard food) more than 12 times per week and pain in the temporomandibular joint (TMJ) (P < 0.05). A positive association was found between pain in the TMJ and older age (15-17 years) (P < 0.001). The prevalence of pain in the TMJ was significantly higher in males (P < 0.01). Prevalences of clicking and pain in the TMJ were significantly higher in subjects living in a rural area than in subjects living in an urban area (P < 0.01 and P < 0.01, respectively). Subjects having one or more decayed, missing and filled teeth (DMFT) showed significantly higher prevalences of clicking (P < 0.01) and restricted mouth opening (P < 0.01). The results suggest that prevalence of TMD symptoms are related to prolonged consumption of hard food items.