ABSTRACT
We have previously reported that significantly higher levels of Keratin 14 (Ker-14) was observed in oral squamous cell carcinoma (OSCC) and severely dysplastic tissues, whereas this expression was reversed in hyperplasia and in mild to moderate dysplasia. In this study, the mechanism of Keratin 14 activation in oral squamous cell carcinoma (OSCC) cell lines (HSC-2, HSC-3 and Ca9-22) was investigated. Reporter analysis demonstrated that an upstream region (-1759/-1629) accounted for efficient promoter activity. Furthermore, electromobility sift and supershift assay demonstrated that interactions of the SP-1/SP-3 complex at the elements resided in -1737/-1702 and -1680/-1652 and may be essential for this activation in OSCC cells.
Subject(s)
Keratins/genetics , Regulatory Sequences, Nucleic Acid/genetics , Sp1 Transcription Factor/metabolism , Sp3 Transcription Factor/metabolism , Binding Sites/genetics , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/pathology , Cell Line, Tumor , Electrophoretic Mobility Shift Assay , Gene Expression Regulation, Neoplastic , Humans , Keratin-14 , Luciferases/genetics , Luciferases/metabolism , Molecular Sequence Data , Mouth Neoplasms/genetics , Mouth Neoplasms/pathology , Mutation , Oligonucleotide Probes/genetics , Oligonucleotide Probes/metabolism , Promoter Regions, Genetic/genetics , Protein Binding , RNA, Messenger/genetics , RNA, Messenger/metabolism , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transcription, Genetic , TransfectionABSTRACT
To identify differentially expressed genes during the development of oral malignancy, differential display, northern blotting, reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical analyses were undertaken using oral squamous cell carcinoma (OSCC) and leukoplakia tissues. Significantly higher levels of keratin (Ker)-14 and -17 mRNAs, combined with lower levels of Ker-4, Ker-13 and transglutaminase 3 (TG-3) transcripts, were observed in OSCC and severely dysplastic tissues, whereas this expression profile was reversed in hyperplasia and in mild to moderate dysplasia. The expression of Ker-4 and Ker-13 was elevated in density-arrested OSCC cell lines (Ca9-22, HSC-2, -3 and -4) but the expression of Ker-17 mRNA was elevated in these cells, regardless of the growth conditions. In addition, Ker-4 and Ker-13 proteins were predominantly expressed in moderate dysplasia and hyperplasia, whereas Ker-17 was markedly expressed in OSCC tissues. The expression patterns of these genes could therefore be an important determinant of the manifestation of oral malignancy.
