Rapid adherence to collagen IV enriches for tumour initiating cells in oral cancer.

BACKGROUND: Although several approaches for identification and isolation of carcinoma cells with tumour initiating properties have been established, enrichment of a population of pure and viable tumour-initiating cells (TICs) is still problematic. This study investigated possibilities to isolate a population of cancer cells with tumour initiating properties based on their adherence properties, rather than expression of defined markers or clonogenicity. METHODS: Several human cell lines derived from oral dysplasia and oral squamous cell carcinoma (OSCC), as well as primary cells derived from patients with OSCC were allowed to adhere to collagen IV-coated dishes sequentially. Rapid adherent cells (RAC), middle adherent cells (MAC) and late adherent cells (LAC) were then harvested and further investigated for their morphology, stem cell-like properties and molecular profile while grown in vitro and tongue xenotransplantation in NOD-SCID mice at serial dilutions. RESULTS: RAC showed significantly higher colony forming efficiency (p<0.05), sphere forming ability, greater migration ability (p<0.05), exhibited longer G2 phase and displayed higher expression of integrin ß1 and other stem-cell related molecules as compared to MAC and LAC. RAC induced tongue tumours in NOD-SCID mice with the highest incidence. These tumours were also bigger and metastasised more frequently in loco-regional lymph nodes than MAC and LAC. CONCLUSIONS: These findings prove for the first time that OSCC cells with tumour initiating properties can be enriched based on their rapid adhesiveness to collagen IV. This separation procedure provides a potentially useful tool for isolating TICs in OSCC for further studies on understanding their characteristics and drug-resistant behaviour.

Identification of FOXM1-induced epigenetic markers for head and neck squamous cell carcinomas.

BACKGROUND: Epigenetic reprogramming of the methylome has been implicated in all stages of cancer evolution. It is now well accepted that cancer cells exploit epigenetic reprogramming, a mechanism that regulates stem/progenitor cell renewal and differentiation, to promote cancer initiation and progression. The oncogene FOXM1 has been implicated in all major forms of human cancer. METHODS: We have recently shown that aberrant upregulation of FOXM1 orchestrated a DNA methylation signature that mimics the cancer methylome landscape, from which we have identified a number of FOXM1-induced epigenetic markers. Differential promoter methylation and gene expression in clinical specimens were measured using commercially available bisulfite conversion kits and absolute quantitative PCR, respectively. RESULTS: Here, we investigated 8 FOXM1-induced differentially methylated genes, SPCS1, FLNA, CHPF, GLT8D1, C6orf136, MGAT1, NDUFA10, and PAFAH1B3, using human head and neck tissue specimens donated by 2 geographically independent patient cohorts from Norway and the United Kingdom. Two genes (GLT8D1 and C6orf136) were found to be differentially expressed in head and neck squamous cell carcinomas (HNSCCs). Using methylation-specific quantitative PCR, we confirmed that the promoters of GLT8D1 and C6orf136 were hypo- and hypermethylated, respectively, in HNSCC tissues. CONCLUSIONS: Given that epigenetic change precedes gene expression, methylation status of candidate genes identified from this study may represent a signature of premalignancy, rendering them potentially useful predictive biomarkers for precancer screening and/or therapeutic targets for cancer prevention.

Exploiting FOXM1-orchestrated molecular network for early squamous cell carcinoma diagnosis and prognosis.

Histopathological discordance with molecular phenotype of many human cancers poses clinically challenging tasks for accurate cancer diagnosis, which impacts on treatment strategy and patient outcome. Hence, an objective, accurate and quantitative method is needed. A quantitative Malignancy Index Diagnostic System (qMIDS) was developed based on 14 FOXM1 (isoform B)-associated genes implicated in the regulation of the cell cycle, differentiation, ageing, genomic stability, epigenetic and stem cell renewal, and two reference genes. Their mRNA expression levels were translated via a prospectively designed algorithm, into a metric scoring system. Subjects from UK and Norway (n = 299) provided 359 head and neck tissue specimens. Diagnostic test performance was assessed using detection rate (DR) and false-positive rate (FPR). The median qMIDS scores were 1.3, 2.9 and 6.7 in healthy tissue, dysplasia and head and neck squamous cell carcinomas (HNSCC), respectively (UK prospective dataset, p<0.001); 1.4, 2.3 and 7.6 in unaffected, oral lichen planus, or HNSCC, respectively (Norwegian retrospective dataset with up to 19 years survival data, p<0.001). At a qMIDS cut-off of 4.0, DR was 94% and FPR was 3.2% (Norwegian dataset); and DR was 91% and FPR was 1.3% (UK dataset). We further demonstrated the transferability of qMIDS for diagnosing premalignant human vulva (n = 58) and skin (n = 21) SCCs, illustrating its potential clinical use for other cancer types. This study provided evidence that qMIDS was able to quantitatively diagnose and objectively stratify cancer aggressiveness. With further validation, qMIDS could enable early HNSCC detection and guide appropriate treatment. Early treatment intervention can lead to long-term reduction in healthcare costs and improve patient outcome.

Surgery and postoperative radiotherapy a valid treatment for advanced oropharyngeal carcinoma.

Since 1992 we have prospectively included all head and neck cancer patients in our health region in a departmental based register. Our hospital takes care of all head and neck cancer patients in our health region consisting of approximately 1 million people. In 1997, we evaluated the results of the treatment of oropharyngeal cancer in the 1992-1997 period. On the basis of this evaluation, we changed our treatment policy for tonsillar and base of tongue carcinoma. We first changed the treatment for the lesions with worst prognosis, i.e., those with T3-T4 carcinomas, from radiotherapy only, to radical surgery and postoperative radiotherapy. We have since that time increasingly also operated the smaller oropharyngeal carcinomas. The 2 years' overall survival and disease-specific survival for all patients diagnosed in the 1992-1997 period was 56 and 63%, respectively. The results from a similar group of patients in the 6 years' period from 2000 to 2005, after the change in treatment, have increased to 83 and 88%. When we looked at the subgroup of patients in the 2000-2005 period treated with surgery and postoperative radiotherapy, 45 out of 69 patients (65%) presenting with an oropharyngeal cancer were fit for operation. With radical surgery and postoperative radiation therapy, the 2 years overall survival is now 91%. The 2-year disease-specific survival is 96% and the locoregional control is 98%. This is a marked improvement as compared to radiotherapy alone and definitely competitive with modern radiochemotherapy.