Induction of Salivary Gland-Like Cells from Dental Follicle Epithelial Cells.

The dental follicle (DF), most often associated with unerupted teeth, is a condensation of ectomesenchymal cells that surrounds the tooth germ in early stages of tooth development. In the present study, we aim to isolate epithelial stem-like cells from the human DF and explore their potential differentiation into salivary gland (SG) cells. We demonstrated the expression of stem cell-related genes in the epithelial components of human DF tissues, and these epithelial progenitor cells could be isolated and ex vivo expanded in a reproducible manner. The human DF-derived epithelial cells possessed clonogenic and sphere-forming capabilities, as well as expressed a panel of epithelial stem cell-related genes, thus conferring stem cell properties (hDF-EpiSCs). When cultured under in vitro 3-dimensional induction conditions, hDF-EpiSCs were capable to differentiate into SG acinar and duct cells. Furthermore, transplantation of hDF-EpiSC-loaded native de-cellularized rat parotid gland scaffolds into the renal capsule of nude mice led to the differentiation of transplanted hDF-EpiSCs into salivary gland-like cells. These findings suggest that hDF-EpiSCs might be a promising source of epithelial stem cells for the development of stem cell-based therapy or bioengineering SG tissues to repair/regenerate SG dysfunction.

Plumbagin suppresses tumor cell growth in oral squamous cell carcinoma cell lines.

OBJECTIVES: Plumbagin (PL), a naturally occurring quinoid, exerts antitumoral effects in diverse types of cancer cells. However, the effect of PL on tumor cell proliferation in oral squamous cell carcinoma (OSCC) remains poorly understood. In this study, we assessed the efficacy of PL, in human OSCC cells. METHODS: The effect of PL on the cell growth and apoptosis of OSCC cell lines was evaluated using MTT and Annexin V assays, respectively. The effect of PL on mitochondrial membrane potential loss and reactive oxygen species (ROS) generation was evaluated using flow cytometry analysis. RESULTS: MTT assay showed that PL dose-dependently suppressed OSCC cell growth, with IC50 values ranging from 3.87 to 14.6 µM. Flow cytometry analysis revealed that PL treatment resulted in a significant decrease in mitochondrial membrane potential and an increase in the number of apoptotic cells. Notably, ROS generation was significantly elevated after PL treatment. Furthermore, a ROS scavenger, N-acetylcysteine (NAC), clearly suppressed the decrease in mitochondrial membrane potential, increase of caspase-3/7 activity, and apoptosis after PL treatment. CONCLUSION: This study provides the considerable evidence of the tumor-suppressive effect of PL, thereby highlighting its therapeutic potential for OSCC treatment.

Mutagenicity screening of pesticides in the microbial system.

A survey on the mutation induction capacity was made in the microbial system on 166 pesticides including 57 fungicides, 63 herbicides and 46 insecticides. The screening methods consisted of the rec-assay procedure, a sensitivity test utilizing H17 Rec+ and M45 Rec- strains of Bacillus subtilis, as well as the reversion assays on plates utilizing auxotrophic strains of Escherichia coli (WP2) and Salmonella typhimurium (Ames series). Chemicals inducing reversions were detected only among those showing positive effects in the rec-assay but not among negative samples. In addition to Captafol, Captan, Dexon and NBT of which mutagenicities have been previously reported, Dichlorvos, Folpet, 2-hydrazinoethanol (HEH), 5-nitro-1-naphthonitrile (NNN) and Vamidothion were found to be mutagens in our systems.