Victor Lopes

Upregulation of Eps8 in oral squamous cell carcinoma promotes cell migration and invasion through integrin-dependent Rac1 activation

Oral squamous cell carcinoma (OSCC) is a lethal disease and early death usually occurs as a result of local invasion and regional lymph node metastases. Current treatment regimens are, to a certain degree, inadequate, with a 5-year mortality rate of around 50% and novel therapeutic targets are urgently required. Using expression microarrays, we identified the eps8 gene as being overexpressed in OSCC cell lines relative to normal oral keratinocytes, and confirmed these findings using RT–PCR and western blotting. In human tissues, we found that Eps8 was upregulated in OSCC (32% of primary tumors) compared with normal oral mucosa, and that expression correlated significantly with lymph node metastasis (P=0.032), suggesting a disease-promoting effect. Using OSCC cell lines, we assessed the functional role of Eps8 in tumor cells. Although suppression of Eps8 produced no effect on cell proliferation, both cell spreading and migration were markedly inhibited. The latter cell functions may be modulated through the small GTP-ase, Rac1 and we used pull-down assays to investigate the role of Eps8 in Rac1 signaling. We found that αvβ6- and α5β1-integrin-dependent activation of Rac1 was mediated through Eps8. Knockdown of either Eps8 or Rac1, inhibited integrin-dependent cell migration similarly and transient expression of constitutively active Rac1 restored migration of cells in which Eps8 expression had been suppressed. We also showed that knockdown of Eps8 inhibited tumor cell invasion in an organotypic model of OSCC. These data suggest that Eps8 and Rac1 are part of an integrated signaling pathway modulating integrin-dependent tumour cell motility and identify Eps8 as a possible therapeutic target.

Squamous cell carcinoma of the oral cavity rarely harbours oncogenic human papillomavirus

Although it is now well established that a significant proportion of oropharyngeal squamous cell carcinomas (SCC) harbour oncogenic human papillomavirus (HPV) sequences, the frequency with which these sequences are detected in oral SCC (excluding oropharyngeal subsites) is highly variable. In an attempt to establish the true prevalence of HPV-16 and HPV-18 subtypes in oral SCC, we screened 142 consecutive cases from a UK cohort using both conventional PCR with consensus primers and type-specific quantitative PCR (Q-PCR), while at the same time employing a rigorous protocol to avoid sample contamination. Q-PCR revealed HPV sequences in five cases; two contained HPV-16 alone, two HPV-18 alone, and one sample carried both genotypes. However, only two of these cases (both HPV-16-positive) had moderate viral loads (51 and 91 viral copies per 100 cells respectively) and were positive for HPV DNA by conventional PCR. Both cases contained HPV DNA in tumour cells as shown by Q-PCR analysis of micro-dissected tissue and by in situ hybridisation. The remaining three cases had only very low viral loads (between 3 and 7 viral copies per 100 cells), were negative by conventional PCR and lacked HPV DNA in tumour cells. Our data provide strong evidence that oncogenic HPV is uncommon in oral SCC and that routine HPV testing of these tumours cannot be advocated.

Facial cutaneous sinuses of dental origin - a diagnostic challenge.

It is common for practitioners to misdiagnose the cause of facial cutaneous sinus tracts, failing to recognise that many have an odontogenic cause. Chronic infection around the apex of a dental root can drain to the mouth or less commonly to the skin via a sinus tract. Dental symptoms are not always present and this confuses the clinical picture further. Failure to identify an odontogenic cause may result in unnecessary and ineffective treatment. Elimination of dental infection via tooth extraction or root canal treatment leads to resolution of the cutaneous sinus. We present a series of cutaneous draining sinuses of dental origin that resolved rapidly following dental treatment and hope to highlight the importance of including odontogenic infection in the differential diagnosis of such a lesion in the head and neck.

Aberrant expression of the S1P regulating enzymes, SPHK1 and SGPL1, contributes to a migratory phenotype in OSCC mediated through S1PR2

Oral squamous cell carcinoma (OSCC) is a lethal disease with a 5-year mortality rate of around 50%. Molecular targeted therapies are not in routine use and novel therapeutic targets are required. Our previous microarray data indicated sphingosine 1-phosphate (S1P) metabolism and signalling was deregulated in OSCC. In this study, we have investigated the contribution of S1P signalling to the pathogenesis of OSCC. We show that the expression of the two major enzymes that regulate S1P levels were altered in OSCC: SPHK1 was significantly upregulated in OSCC tissues compared to normal oral mucosa and low levels of SGPL1 mRNA correlated with a worse overall survival. In in vitro studies, S1P enhanced the migration/invasion of OSCC cells and attenuated cisplatin-induced death. We also demonstrate that S1P receptor expression is deregulated in primary OSCCs and that S1PR2 is over-expressed in a subset of tumours, which in part mediates S1P-induced migration of OSCC cells. Lastly, we demonstrate that FTY720 induced significantly more apoptosis in OSCC cells compared to non-malignant cells and that FTY720 acted synergistically with cisplatin to induce cell death. Taken together, our data show that S1P signalling promotes tumour aggressiveness in OSCC and identify S1P signalling as a potential therapeutic target.

Predicting the choice of anaesthesia for third molar surgery – guideline or the easy-line?

Objective To observe trends in choice of anaesthetic for mandibular third molar surgery in the Combined Department of Oral and Maxillofacial Surgery and Oral Medicine, based at the Edinburgh Dental Institute (EDI) and St Johns Hospital (SJH) in Livingston.Method Data were collected retrospectively from electronic patient records for 301 consecutive new referrals for mandibular third molar surgery from general dental practitioners to each of the oral and maxillofacial departments in the EDI and SJH from the 1 September 2009 onwards. Date of consultation, grade of assessing clinician, age, gender, postcode, required surgical procedure, choice of anaesthetic and predicted difficulty of procedure were analysed.Results One hundred and fifty patients were seen at the EDI and 151 at SJH. There was no statistically significant difference in the proportion of male and female patients or age of patients presenting at each site. Seventeen patients (11.3%) were listed for a general anaesthetic, 21 (14%) for conscious intravenous sedation and 112 (74.7%) for local anaesthetic at EDI. At SJH 57 patients (37.7%) were listed for a general anaesthetic, 30 (19.9%) for conscious intravenous sedation and 64 (42.4%) for local anaesthetic. There was only a small difference in the difficulty of cases at the two sites, though there was a significant difference in socioeconomic deprivation between the two populations.Conclusions Significantly more general anaesthetics are being prescribed for mandibular third molar surgery at SJH than the EDI. This finding is not related to difficulty of the cases presenting at each site but may be related to the nature of a maxillofacial clinic compared to a dedicated oral surgery centre. The difference in socioeconomic deprivation may have had an impact on patient decisions.

HOPX functions as a tumour suppressor in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is generalized term that encompasses a diverse group of cancers that includes tumours of the oral cavity (OSCC), oropharynx (OPSCC) and nasopharynx (NPC). Genetic alterations that are common to all HNSCC types are likely to be important for squamous carcinogenesis. In this study, we have investigated the role of the homeodomain-only homeobox gene, HOPX, in the pathogenesis of HNSCC. We show that HOPX mRNA levels are reduced in OSCC and NPC cell lines and tissues and there is a general reduction of HOPX protein expression in these tumours and OPSCCs. HOPX promoter methylation was observed in a subset of HNSCCs and was associated with a worse overall survival in HPV negative tumours. RNAseq analysis of OSCC cells transfected with HOPX revealed a widespread deregulation of the transcription of genes related to epithelial homeostasis and ectopic over-expression of HOPX in OSCC and NPC cells inhibited cell proliferation, plating efficiency and migration, and enhanced sensitivity to UVA-induced apoptosis. Our results demonstrate that HOPX functions as a tumour suppressor in HNSCC and suggest a central role for HOPX in suppressing epithelial carcinogenesis.

Epidemiological study of alendronate-related osteonecrosis of the jaw in the southeast of Scotland

We aimed to establish the incidence of alendronate-related osteonecrosis of the jaw (ONJ) in the southeast of Scotland, and to assess the effect of corticosteroids on it. We studied a prospective case series of patients between June 2004 and March 2012 separated into steroid and non-steroid groups. There were 34 cases of alendronate-related ONJ and 78732 drug patient years (DPY) of alendronate, making the overall occurrence 43.1 cases/100000 DPY. There were 12 patients in the steroid group (mean (range) age 68.2 (48-87) years) making 42.5 cases/100000 DPY, and 22 in the non-steroid group (mean (range) age 76.2 (63-91) years) making 119.6 cases/100000 DPY. The mean (range) age at presentation of alendronate-related ONJ was significantly lower in the steroid group (68.2 (48-87) compared with 76.2 (63-91) years, p=0.019) as was the duration of exposure to alendronate before it developed (28.9 (6-120) compared with 61.3 (13-168) months, p=0.03). The overall incidence seems to be higher in the southeast of Scotland than elsewhere. Concurrent use of corticosteroids is not associated with an increased incidence of alendronate-related ONJ, but it seems to reduce the duration of exposure before it develops. Age is likely to be a confounding factor.

Necrotising sialometaplasia in the floor of mouth

IntroductionNecrotising sialometaplasia is a benign self-limiting inflammatory process which occurs in the salivary gland tissue. The condition is a diagnostic challenge mimicking malignancy both clinically and histopathologically. Commonly, it presents in the hard palate.Case reportHere, we report an unusual case in a 56-year-old man which presented in the floor of the mouth.