Photodynamic therapy leads to complete remission of tongue tumors and inhibits metastases to regional lymph nodes.

In patients diagnosed with oral cancer, the most important prognostic indicator for patient survival after primary treatment is metastasis to the cervical lymph nodes or distal sites. Therefore, we evaluated the utility of photodynamic therapy (PDT) mediated by aluminum-chloride-phthalocyanine entrapped in liposomes for the prevention of metastasis to regional cervical lymph nodes in the Erhlich tongue cancer model. The PDT protocol led to complete remission of tongue tumours and prevented the occurrence of regional metastasis. The prevention of regional metastasis was confirmed by histopathological and immunohistochemical analyses. In addition, PDT treatment increased the overall survival and reduced weight loss relative to control tumour-bearing mice. Thus, PDT should be clinically evaluated for use in the prevention of cervical lymph node metastasis in patients with oral cancer.

DNA damage and apoptosis induced by Pteridium aquilinum aqueous extract in the oral cell lines HSG and OSCC-3.

BACKGROUND: Bracken fern (Pteridium aquilinum) has been consumed by humans and animals for centuries. However, its consumption is associated with a high incidence of cancer in the upper digestory tract of different species. Although the oral cavity is the first site of contact with ingested toxic substances, the interaction of bracken fern composites with oral cell lines has not yet been studied. METHODS: In order to study the biological responses of oral cells exposed to bracken fern, we evaluated the genotoxic and cytotoxic effects of a bracken fern aqueous extract in oral cell lines. Human submandibular gland (HSG) and human oral epithelium cells (OSCC-3) cells were treated with three different concentrations of the extract. DNA damage was determined by the comet assay, and cellular morphology was examined by light microscopy. Apoptotic changes were evaluated by transmission electron microscopy and TUNEL assay. RESULTS: The comet assay revealed that the extract was genotoxic for both cell lines but the results were not dose-dependent. The morphological and ultrastructural analyses showed that the extract caused conspicuous alterations in both cell types: uncommon chromatin condensation, nuclear picnosis, cellular volume decrease, nuclear envelope disruption, formation of numerous vacuoles of different sizes and apoptotic bodies. The TUNEL assay confirmed apoptosis induction. CONCLUSIONS: These results demonstrate that the extract was cytotoxic to HSG and OSCC-3 cells, and that cellular degeneration occurred mainly by apoptosis. We believe that oral cells could trigger apoptosis after bracken fern induced DNA damage, in order to avoid the malignant transformation.

Interaction of bracken-fern extract with vitamin C in human submandibular gland and oral epithelium cell lines.

The consumption of bracken-fern (Pteridium aquilinum) as food is associated with a high incidence of cancer in humans and animals. Thus far, the carcinogenic effects of bracken-fern consumption could be related to chromosome aberrations verified in animal and in human peripheral lymphocytes. We tested the in vitro effects of vitamin C (10 and 100 microg/ml) on the reversibility of DNA damage caused by bracken-fern on human submandibular gland (HSG) cells and on oral epithelium cells (OSCC-3) previously exposed to bracken-fern extract. DNA damage (i.e. nuclei with increased levels of DNA migration) was determined by comet assay, cell morphology was evaluated by light microscopy and cellular degeneration was assessed by the acridine orange/ethidium bromide fluorescent-dyeing test. Results showed that vitamin C alone did not reduce DNA damage caused by bracken-fern in HSG and OSSC-3 cells. However, at a higher concentration (100 microg/ml), vitamin C induced DNA damage in both cell lines. Moreover, vitamin C (10 and 100 microg/ml) together with bracken-fern extract showed synergistic effects on the frequency of DNA damage in HSG cells. In addition, cells treated with bracken-fern extract or vitamin C alone, or with their association, showed apoptosis morphological features, such as chromatin condensation, cytoplasmic volume loss, changes in membrane symmetry and the appearance of vacuoles; these alterations were observed in both cell lines. These results demonstrate that bracken-fern extract was cytotoxic to HSG and OSCC-3 cells, causing cell death by apoptosis, and that vitamin was not able to revert these effects.