Hypoxia-mediated apoptosis in oral carcinoma cells occurs via two independent pathways

BACKGROUND: We are attempting to elucidate the mechanism of apoptotic cell death induced by hypoxia in oral cancer cells. Since hypoxia can render solid tumors more resistant to radiation and chemotherapy, understanding the pathways involved in hypoxia-induced apoptosis of oral cancer cells would be of significant therapeutic value. RESULTS: Here we showed that oral cancer cells from primary tumor and lymph node metastasis undergo apoptosis after 24 to 48 h of hypoxia. During hypoxic growth, an increase in caspase-3 proteolytic activity was observed, accompanied by the cleavage of PARP (poly (ADP-ribose) polymerase) indicative of caspase activity. In addition, hypoxic stress also lead to activation of caspase-8, -9, and -10 but not -1, elicited the release of cytochrome C into the cytosol, and resulted in internucleosomal DNA fragmentation. CONCLUSION: These results show that hypoxia-induced apoptosis in oral carcinoma cell lines relies on both intrinsic (mitochondrial) and extrinsic (cell death receptor mediated) pathways. This novel evidence will assist in designing more efficient combination chemotherapy approaches as promising strategy for the treatment of oral cancers

Multimodal optical imaging platform for the early diagnosis for oral neoplasia

Early diagnosis is critical to reducing the global burden of oral cancer. In the US, 65% of oral cancer patients are diagnosed after regional metastasis; these patients have a 50% five-year mortality compared to 17% for those with localized disease. A major reason for late diagnosis is that clinicians are unable to accurately distinguish neoplastic lesions, which require treatment, from benign lesions. Furthermore, clinicians are unable to accurately select to biopsy the site with the worst diagnosis within a larger lesion. Please download the file below for full content

Acquiring Metastatic Competence by Oral Squamous Cell Carcinoma Cells Is Associated with Differential Expression of α-Tubulin Isoforms

We performed comparative global proteomics analyses of patient-matched primary (686Tu) and metastatic (686Ln) OSCC cells. The metastatic OSCC 686Ln cells showed greater in vitro migratory/invasive potential and distinct cell shape from their parental primary 686Tu cells. Ettan DIGE analysis revealed 1316 proteins spots in both cell lines with >85% to be quantitatively similar (<2 folds) between the two cell lines. However, two protein spots among four serial spots were highly dominant in 686Ln cells. Mass spectrometry sequencing demonstrated all four spots to be α-tubulin isotypes. Further analysis showed no significant quantitative difference in the α-tubulin between the two cell lines either at mRNA or protein levels. Thus, two distinct isoforms of α-tubulin, probably due to posttranslational modification, were associated with metastatic 686Ln cells. Immunofluorescence demonstrated remarkable differences in the cytosolic α-tubulin distribution patterns between the two cells. In 686Tu cells, α-tubulin proteins formed a normal network composed of filaments. In contrast, α-tubulin in 686Ln cells exhibited only partial cytoskeletal distribution with the majority of the protein diffusely distributed within the cytosol. Since α-tubulin is critical for cell shape and mobility, our finding suggests a role of α-tubulin isoforms in acquisition of metastatic phenotype and represents potential target for therapeutic intervention

Myositis ossificans circumscripta of the buccinator muscle: first report of a rare complication of mandibular third molar extraction.

Myositis ossificans is a self-limiting ossifying process that most often develops following mechanical trauma to skeletal musculature. It chiefly affects the skeletal muscles of extremities of young athletically active adult males. Myositis ossificans is rare in children except for children affected by heritable disorder known as progressive myositis ossificans (fibrodysplasia ossificans progressiva). Children with this disorder develop ossification of muscles and associated soft tissue in early childhood without prior history of trauma. Traumatic form of myositis ossificans also known as myositis ossificans circumscripta (MOC) is rarely encountered in the head and neck musculature. We report a case of MOC within the buccinator which developed as a postoperative complication of mandibular third molar surgery. During extraction of a left mandibular third molar in a 16-year old male, a tooth fragment was accidently displaced into the adjacent soft tissue. Retrieval of this tooth fragment caused significant soft tissue trauma. Eighteen months after his third molar surgery, the patient continued to have pain and tenderness anterior to the left mandibular ramus. Radiographic imaging revealed a well-defined ovoid radiopaque mass within the left buccinator muscle. The lesion was surgically removed and the post-surgical course of the patient was uneventful. Histological findings of the mass were characteristic for myositis ossificans

Rollerball microendoscope for mosaicking in high-resolution oral imaging

Only 40% of oral cancers are diagnosed at an early, localized stage, when treatment is most effective [1]. Thus, implementing diagnostic imaging tools for early detection of highgrade dysplasia and cancer may help improve the survival rate of oral cancer patients [2]. The highresolution microendoscope (HRME) is a compact, portable, fiberbased imaging device that can image cell nuclei in tissue labeled with the fluorescent contrast agent proflavine [3]. The HRME allows clinicians to noninvasively image the size, shape and distribution of epithelial cell nuclei in vivo, enabling realtime evaluation of potentially neoplastic lesions [3]. The primary limitation of the HRME is the small field of view of its fiber probe (720 μm), which makes it timeconsuming to examine large areas of tissue. Mosaicking algorithms have previously been implemented to allow realtime generation of image mosaics during HRME imaging, thus interrogating a larger field of view than the fiber probe’s diameter [4]. However, this approach has had limited success in vivo due to the practical difficulty of translating the fiber probe across the tissue in a smooth, controlled manner in order for the mosaicking software to function properly. Here we report the construction and initial testing of a rollerball HRME probe that permits smooth, rolling translation across the tissue surface while maintaining image quality with subcellular resolution. The rollerball HRME consists of a standard HRME probe interfaced with a rollerball mechanism. The mechanism is composed of two 5mm sapphire ball lenses enclosed within a 3D printed penlike casing. The ball lenses serve as an optical relay, while the distal ball lens also serves as a rolling contact point with the tissue surface. Figure 1 shows the use of the rollerball HRME to generate a realtime mosaic of a calibration target (field finder slide) as it rolls across the surface of the target. Figure 2 shows the use of the rollerball HRME to generate a realtime mosaic showing cell nuclei on the lateral tongue of a healthy volunteer as it rolls across the tissue surface. The rollerball HRME will allow clinicians to more rapidly examine large areas of tissue with subcellular resolution, potentially aiding in the early detection of highgrade oral dysplasia and cance. Please click Additional Files below to see the full abstract

Programmable bio-nanochip-based cytologic testing of oral potentially malignant disorders in Fanconi anemia

Fanconi anemia (FA) is caused by mutations of DNA repair genes. The risk of oral squamous cell carcinoma (OSCC) among FA patients is 800-folds higher than in the general population. Early detection of OSCC, preferably at it precursor stage, is critical in FA patients to improve their survival. In an ongoing clinical trial, we are evaluating the effectiveness of the programmable bio-nanochip (p-BNC)-based oral cytology test in diagnosing oral potentially malignant disorders (OPMD) in non-FA patients. We used this test to compare cytomorphometric and molecular biomarkers in OSCC cell lines derived from FA and non-FA patients to brush biopsy samples of a FA patient with OPMD and normal mucosa of healthy volunteers. Our data showed that expression patterns of molecular biomarkers were not notably different between sporadic and FA-OSCC cell lines. The p-BNC assay revealed significant differences in cytometric parameters and biomarker MCM2 expression between cytobrush samples of the FA patient and cytobrush samples of normal oral mucosa obtained from healthy volunteers. Microscopic examination of the FA patient's OPMD confirmed the presence of dysplasia. Our pilot data suggests that the p-BNC brush biopsy test recognized dysplastic oral epithelial cells in a brush biopsy sample of a FA patient

Repression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) but not its receptors during oral cancer progression

BACKGROUND: TRAIL plays an important role in host immunosurveillance against tumor progression, as it induces apoptosis of tumor cells but not normal cells, and thus has great therapeutic potential for cancer treatment. TRAIL binds to two cell-death-inducing (DR4 and DR5) and two decoy (DcR1, and DcR2) receptors. Here, we compare the expression levels of TRAIL and its receptors in normal oral mucosa (NOM), oral premalignancies (OPM), and primary and metastatic oral squamous cell carcinomas (OSCC) in order to characterize the changes in their expression patterns during OSCC initiation and progression. METHODS: DNA microarray, immunoblotting and immunohistochemical analyses were used to examine the expression levels of TRAIL and its receptors in oral epithelial cell lines and in archival tissues of NOM, OPM, primary and metastatic OSCC. Apoptotic rates of tumor cells and tumor-infiltrating lymphocytes (TIL) in OSCC specimens were determined by cleaved caspase 3 immunohistochemistry. RESULTS: Normal oral epithelia constitutively expressed TRAIL, but expression was progressively lost in OPM and OSCC. Reduction in DcR2 expression levels was noted frequently in OPM and OSCC compared to respective patient-matched uninvolved oral mucosa. OSCC frequently expressed DR4, DR5 and DcR1 but less frequently DcR2. Expression levels of DR4, DR5 and DcR1 receptors were not significantly altered in OPM, primary OSCC and metastatic OSCC compared to patient-matched normal oral mucosa. Expression of proapoptotic TRAIL-receptors DR4 and DR5 in OSCC seemed to depend, at least in part, on whether or not these receptors were expressed in their parental oral epithelia. High DR5 expression in primary OSCC correlated significantly with larger tumor size. There was no significant association between TRAIL-R expression and OSSC histology grade, nodal status or apoptosis rates of tumor cells and TIL. CONCLUSION: Loss of TRAIL expression is an early event during oral carcinogenesis and may be involved in dysregulation of apoptosis and contribute to the molecular carcinogenesis of OSCC. Differential expressions of TRAIL receptors in OSCC do not appear to play a crucial role in their apoptotic rate or metastatic progression

Incidental detection of an occult oral malignancy with autofluorescence imaging: a case report

BACKGROUND: Autofluorescence imaging is used widely for diagnostic evaluation of various epithelial malignancies. Cancerous lesions display loss of autofluorescence due to malignant changes in epithelium and subepithelial stroma. Carcinoma of unknown primary site presents with lymph node or distant metastasis, for which the site of primary tumour is not detectable. We describe here the use of autofluorescence imaging for detecting a clinically innocuous appearing occult malignancy of the palate which upon pathological examination was consistent with a metastatic squamous cell carcinoma. CASE DESCRIPTION: A submucosal nodule was noted on the right posterior hard palate of a 59-year-old white female during clinical examination. Examination of this lesion using a multispectral oral cancer screening device revealed loss of autofluorescence at 405 nm illumination. An excisional biopsy of this nodule, confirmed the presence of a metastatic squamous cell carcinoma. Four years ago, this patient was diagnosed with metastatic squamous cell carcinoma of the right mid-jugular lymph node of unknown primary. She was treated with external beam irradiation and remained disease free until current presentation. CONCLUSION: This case illustrates the important role played by autofluorescence tissue imaging in diagnosing a metastatic palatal tumour that appeared clinically innocuous and otherwise would not have been biopsied