Current evidence implicates aberrant microRNA expression patterns in human malignancies; measurement of microRNA expression may have diagnostic and prognostic applications. Roles for microRNAs in head and neck squamous cell carcinomas (HNSCC) are largely unknown. HNSCC, a smoking-related cancer, is one of the most common malignancies worldwide but reliable diagnostic and prognostic markers have not been discovered so far. Some studies have evaluated the potential use of microRNA as biomarkers with clinical application in HNSCC.

Head and neck squamous cell carcinoma is a complex disease with several etiologic factors and different molecular changes that may trigger certain events; it is also globally one of the most common malignancies in this topography. Extracts from Viscum album L. (VA) (mistletoe) have been used as adjuvant therapies with promising results in several types of cancer, mainly in European countries. In vitro studies have demonstrated that various types of VA may have cytotoxicity in carcinoma cells, activating the apoptotic cascade or leading cells to necrosis. This study aimed to verify the effects of three types of VA extracts (Iscador Qu Spezial, Iscador P and Iscador M) in squamous cell carcinoma of the tongue cell lines SCC9 and SCC25, not previously studied. A concentration of 0.3 mg/ml (IC50) of the drugs induced apoptosis, affecting gene expression and protein levels of AKT, PTEN and CYCLIN D1. It was concluded that VA extracts have a cytotoxic effect on SCC9 and SCC25 cell lines, but while SCC9 cell line was more resistant to the action of the drugs, Iscador Qu Spezial and Iscador M have higher cytotoxic potential in both cell lines compared to Iscador P.

Natural triterpenes exhibit a wide range of biological activities. Since this group of secondary metabolites is structurally diverse, effects may vary due to distinct biochemical interactions within biological systems. In this work, we investigated the anticancer-related activities of the quinone-methide triterpene maytenin and its derivative compound 22-β-hydroxymaytenin, obtained from Maytenus ilicifolia roots cultivated in vitro. Their antiproliferative and pro-apoptotic activities were evaluated in monolayer and three-dimensional cultures of immortalized cell lines. Additionally, we investigated the toxicity of maytenin in SCID mice harboring tumors derived from a squamous cell carcinoma cell line. Both isolated molecules presented pronounced pro-apoptotic activities in four cell lines derived from head and neck squamous cell carcinomas, including a metastasis-derived cell line. The molecules also induced reactive oxygen species (ROS) and down-regulated microRNA-27a and microRNA-20a/miR-17-5p, corroborating with the literature data for triterpenoids. Intraperitoneal administration of maytenin to tumor-bearing mice did not lead to pronounced histopathological changes in kidney tissue, suggesting low nephrotoxicity. The wide-ranging activity of maytenin and 22-β-hydroxymaytenin in head and neck cancer cells indicates that these molecules should be further explored in plant biochemistry and biotechnology for therapeutic applications.

The presence of Candida albicans in the biofilm underlying the dental prosthesis is related to denture stomatitis (DS), an inflammatory reaction of the oral mucosa. The oral epithelium, a component of the innate immune response, has the ability to react to fungal invasion. In this study, we evaluated the in vitro effect of viable C. albicans on the apoptosis, nitric oxide (NO) production, and β-defensin 2 (hBD-2) expression and production of human palate epithelial cells (HPECs). We further determined whether or not these effects were correlated with fungal invasion of epithelial cells. Interaction between HPEC primary culture and C. albicans was obtained through either direct or indirect cell–cell contact with a supernatant from a hyphal fungus. We found that the hyphae supernatants were sufficient to induce slight HPEC apoptosis, which occurred prior to the activation of the specific mechanisms of epithelial defense. The epithelial defense responses were found to occur via NO and antimicrobial peptide hBD-2 production only during direct contact between C. albicans and HPECs and coincided with the fungus’s intraepithelial invasion. However, although the hBD-2 levels remained constant in the HPEC supernatants over time, the NO release and hBD-2 gene expression were reduced at a later time (10 h), indicating that the epithelial defense capacity against the fungal invasion was not maintained in later phases. This aspect of the immune response was associated with increased epithelial invasion and apoptosis maintenance.